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Impey, Danielle. "Assessment of Transcranial Direct Current Stimulation (tDCS) on MMN-Indexed Auditory Sensory Processing." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/35576.
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Transcranial direct current stimulation (tDCS) is a non-invasive form of brain stimulation which uses a very weak constant current to temporarily excite or inhibit activity in the brain area of interest via electrodes placed on the scalp, depending on the polarity and strength of the current. Presently, tDCS is being used as a tool to investigate frontal cognition in healthy controls and to improve symptoms in neurological and psychiatric patients. Relatively little research has been conducted with respect to tDCS and the auditory cortex (AC). The primary aim of this thesis was to elucidate the effects of tDCS on auditory sensory discrimination, assessed with the mismatch negativity (MMN) event-related potential (ERP). In the first pilot study, healthy participants were assessed in a randomized, double-blind, sham-controlled design, in which participants received anodal tDCS over the primary AC (2 mA for 20 minutes) in one session and ‘sham’ stimulation (i.e. no stimulation) in the other. Pitch MMN was found to be enhanced after receiving anodal tDCS, with the effects being evidenced in individuals with relatively low (vs. high) baseline amplitudes. No significant effects were seen with sham stimulation. A second study examined the separate and interacting effects of anodal and cathodal tDCS on MMN measures. MMN was assessed pre- and post-tDCS (2 mA, 20 minutes) in 2 separate sessions, one involving sham stimulation, followed by anodal stimulation, and one involving cathodal stimulation, followed by anodal stimulation. Only anodal tDCS over the AC increased pitch MMN in baseline-stratified groups, and while cathodal tDCS decreased MMN, subsequent anodal stimulation did not significantly alter MMNs. As evidence has shown that tDCS lasting effects may be dependent on N-methyl-D-aspartate (NMDA) receptor activity, a pharmacological study investigated the use of dextromethorphan (DMO), an NMDA antagonist, to assess possible modulation of tDCS’ effects on both MMN and working memory (WM) performance. The study involved four test sessions that compared pre- and post-anodal tDCS over the AC and sham stimulation with both DMO (50 mL) and placebo administration. MMN amplitude increases were only seen with anodal tDCS with placebo administration, not with sham stimulation, nor with DMO administration. In the sham condition, DMO decreased MMN amplitudes. Anodal tDCS improved WM performance in the active drug condition. Findings from this study contribute to the understanding of underlying neurobiological mechanisms mediating tDCS-sensory and memory improvements. As cognitive impairment has been proposed to be the core feature of schizophrenia disorder (Sz) and MMN is a putative biomarker of Sz, a pilot study was conducted to assess the effects of pre- and post-tDCS on MMN measures in 12 Sz patients, as well as WM performance. Temporal, frontal and sham tDCS were applied in separate sessions. Results demonstrated a trend for pitch MMNs to increase with anodal temporal tDCS, which was significant in a subgroup of Sz individuals with auditory hallucinations, who had low MMNs at baseline. Anodal frontal tDCS significantly increased WM performance, which was found to positively correlate with MMN-tDCS effects. The findings contribute to our understanding of tDCS effects for MMN-indexed sensory discrimination and WM performance in healthy participants and individuals with Sz disorder and may have implications for treatment of sensory processing deficits in neuropsychiatric illness.
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Besson, Pierre. "Using of transcranial direct-current stimulation during motor task for a better outcome." Thesis, Montpellier, 2017. http://www.theses.fr/2017MONT4004/document.
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De tout temps, les humains ont cherché différents moyens pour améliorer leur quotidien. Avec les avancées technologiques actuelles, cette quête s’en trouve facilitée, notamment dans la volonté d’accroître leurs capacités cognitives et/ou motrices. La neuro imagerie permet dorénavant de renseigner les aires cérébrales activées lors de différentes tâches fonctionnelles. Il est aussi possible de moduler l’activité cérébrale en stimulant localement le cerveau avec de faibles courants électriques. Une des techniques les plus répandues à cet effet est appelée tDCS pour transcranial direct current stimulation. Il s’agit en fonction de la polarité du courant induit de moduler à la hausse (stimulation anodale) ou à la baisse (stimulation cathodale) l’excitabilité cortico-spinale en dépolarisant ou en hyperpolarisant la membrane des neurones, respectivement. Malgré une démocratisation grandissante de la neuromodulation via tDCS, les résultats rapportés par la communauté scientifique sont relativement hétérogènes. Les travaux initiés au début des années 2000 sont remis en cause par des résultats actuels faisant état d’une variabilité inter et intra individuelle assez importante. Cette pierre d’achoppement nécessite de développer de nouveaux protocoles d’application de la tDCS. Dans cette thèse, nous avons étudié plusieurs modalités d’application de la tDCS afin d’accroître la persistance des effets neuroplastiques induits et d’augmenter les performances comportementales. Deux études ont été menées afin de révéler dans un premier temps les apports induits par le couplage tâche motrice-tDCS pour ensuite mettre en avant les effets cumulatifs de la répétition de sessions de tâche motrice-tDCS avec pré conditionnement sur la performance motrice. La première étude à travers l’utilisation de la spectroscopie dans le proche infrarouge a permis de rapporter des changements hémodynamiques distincts subséquents au couplage tâche motrice-tDCS par rapport à des protocoles tDCS plus conventionnels. La primauté de l’utilisation concomitante de la tDCS à la tâche motrice a été révélée par la moindre activation du cortex sensorimoteur durant la stimulation ainsi que par une activation cérébrale retardée accrue qui pourrait représenter une réorganisation neuroplastique. La seconde étude s’est intéressée aux effets de la polarité du conditionnement lors de sessions répétées avec comme objectif d’améliorer l’apprentissage et la rétention du système sensorimoteur. Le conditionnement par tDCS était plus propice lors de sessions répétées à engendrer des performances motrices supérieures contrairement à la condition sham. La polarité cathodale engendrait une persistance prolongée. Les premiers résultats de ces travaux de thèse ont permis de défendre l’usage concomitant de la tDCS avec la tâche motrice. De futures recherches sont nécessaires afin d’étudier le transfert de ces résultats dans le monde de l’entraînement ainsi que celui de la réhabilitationHistorically, humans have sought various ways to improve their daily lives. With the current technological advances, this quest is facilitated, especially in the desire to increase their cognitive and / or motor skills. Neuro imagery now makes it possible to inform the areas activated during different functional tasks. Today, it is now possible to modulate brain activity by stimulating the brain locally with weak electrical currents. One of the most common techniques for this purpose is called tDCS for transcranial direct current stimulation. The polarity of the induced current (anodal or cathodal stimulation) allows to modulate upward or downward cortico-spinal excitability by depolarizing or hyperpolarizing the membrane of the neurons, respectively. Despite a growing interest of neuromodulation techniques via tDCS, the results reported by the scientific community are relatively heterogeneous. The work initiated at the beginning of the 2000s is called into question by current results showing a rather large inter and intra variability. This stumbling block requires the development of new protocols for the application of anodal tDCS (atDCS). In this thesis, we were interested in optimizing atDCS protocols in order to increase the persistence of the induced-neuroplastic effects and to increase the behavioral performances. Two studies were carried out in order to first reveal the impact from the motor task/atDCS coupling and then to highlight the cumulative effects of multiple motor-tDCS task sessions with priming atDCS on motor performance. The first study through the use of near infrared spectroscopy allowed to report various hemodynamic changes subsequent to the motor task/atDCS coupling with respect to independent and controlled stimulation protocols. The primacy of the concomitant use of tDCS with the motor task was revealed by the slightest activation of the sensorimotor cortex during stimulation and by an increased delayed cerebral activation which could represent a neuroplastic reorganization. The second study examined the effects of repeated atDCS sessions with anoadal or cathodal tDCS priming in order to improve the learning and retention gains of the sensorimotor system. TDCS priming was more favorable for repeated atDCS sessions to generate higher motor performances contrary to sham. The cathodal polarity produced prolonged persistence. The major findings of this work allow to support the concomitant use of atDCS with the motor task. Future research is needed to study the transfer of these results into the fields of coaching and rehabilitation
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Forgione, Margherita. "Neuromodulation by transcranial direct current stimulation: investigation on reading processes." Doctoral thesis, Università degli studi di Padova, 2015. http://hdl.handle.net/11577/3424152.
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Reading is a human skill, fundamental for everyday life, in which a lot of information is given in written form. To explain this process, several theories were advanced: currently there is common agreement on the simultaneous activation of two ways of reading, the direct or lessical one for words, and the phonological one for non-words or novel words. Neuroimaging studies converge in identifying three basic systems for reading, mostly in the left hemisphere: among these, the temporoparietal cortex (TPc) seems to be involved in grapheme to phoneme conversion (phonological route). The aim of the present work is to investigate, through transcranial direct current stimulation (tDCS), the role of TPc in words and non words reading. We also want to investigate different parameters of stimulation. Results of first study suggest bilateral TPc role in reading, and a facilitatory effect of left cathodal-right anodal stimulation on reading onset times. The second study suggest that reference electrode can lead to different effects depending on its position, and that unilateral montage is not as effective as bilateral one, not involving both TPc. The third study suggest that 10 minutes of tDCS are not enough to achieve a modulation, but confirm the role of TPc. The last study with below average readers, suggest that activation state of the stimulated area and difficulty of the task have to be considered too. This work contributes to the study of neural bases of reading and on the functioning of transcranial direct current stimulation on cognitive functions.La lettura è una competenza umana, fondamentale per la vita di tutti i giorni, in cui molte informazioni sono fornite in forma scritta. Nel tentativo di spiegare questo processo, diverse teorie sono state avanzate: attualmente vi è comune accordo sull’attivazione simultanea di due vie di lettura, quella diretta o lessicale, per la lettura di parole, e quella fonologica per le parole nuove o le non parole. Gli studi di neuroimaging convergono nell'identificare tre sistemi di base per la lettura, per lo più nell'emisfero di sinistra: tra queste, la corteccia temporo-parietale (TPC) sembra essere coinvolta nella conversione da grafema a fonema (via fonologica). Lo scopo del presente lavoro è quello di indagare, attraverso la stimolazione transcranica a corrente continua (tDCS), il ruolo di TPc nella lettura di parole e non parole. Contemporaneamente vogliamo indagare il ruolo dei diversi parametri di stimolazione. I risultati del primo studio suggeriscono un ruolo di TPc bilaterale nella lettura, ed evidenziano un effetto facilitatorio di sui tempi di risposta vocale con stimolazione catodica sinistra-anodica destra. Il secondo studio suggerisce che l’elettrodo di riferimento può portare ad effetti diversi a seconda della sua posizione, e che il montaggio unilaterale non è efficace come quello bilaterale, coinvolgendo solo la TPc sinistra. Il terzo studio mostra che 10 minuti di tDCS non sono sufficienti per una modulazione efficace, ma conferma il ruolo di TPc. L'ultimo studio è sui lettori con una prestazione di lettura inferiore alla media, ed evidenzia l’importanza dello stato di attivazione dell’area stimolata e della difficoltà del compito. Questo lavoro contribuisce allo studio delle basi neurali del processo di lettura e del funzionamento della stimolazione transcranica a corrente continua sulle funzioni cognitive.
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Qin, Jing. "The effects of transcranial direct current stimulation (tDCS) on balance control in Parkinson's disease (PD)." Thesis, Queensland University of Technology, 2021. https://eprints.qut.edu.au/211438/1/Jing_Qi_Thesis.pdf.
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Wagner, Jessica. "Effects of Transcranial Direct Current Stimulation on Expression of Immediate Early Genes (IEG’s)." Wright State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=wright1407255006.
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Reidler, Jay S. "Modulation of Pain with Transcranial Direct Current Stimulation and Diffuse Noxious Inhibitory Controls." Thesis, Harvard University, 2014. http://etds.lib.harvard.edu/hms/admin/view/48.
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Background: While pain is essential for physiological functioning, chronic or pathologic pain is responsible for a major burden of disease in society. Novel approaches to treating acute and chronic pain have employed neuromodulatory tools to target the central and peripheral neural structures that mediate pain. Transcranial direct current stimulation (tDCS), for example, is a safe, non-invasive brain stimulation technique that has been shown in preliminary studies to reduce chronic pain when applied to the primary motor cortex. In contrast to this exogenous neuromodulatory approach, diffuse noxious inhibitory controls (DNIC) refers to endogenous pain regulatory mechanisms that decrease pain following introduction of heterotopic noxious stimuli. This thesis explores whether combining these exogenous and endogenous pain modulation approaches synergistically increases the threshold at which pain is perceived.
Methods: We conducted a double-blinded, randomized, placebo-controlled trial with a crossover design to investigate the effects of tDCS and DNIC on pain thresholds in 15 healthy human subjects. Pain thresholds were assessed prior to and following administration of active tDCS, sham tDCS, cold-water-induced DNIC, and combined active tDCS and DNIC. Using magnetic resonance spectroscopy, we examined whether baseline concentrations of brain metabolites such as N-acetylaspartate in pain-related regions of interest were associated with responses to the varying neuromodulatory conditions.
Results: Pain thresholds significantly increased following both active tDCS and the DNIC paradigm. These modulatory approaches appeared to have additive effects when combined. Pain threshold increases after active tDCS were positively correlated with baseline levels of N-acetylaspartate, a marker of good neural function, in the anterior cingulate cortex and negatively correlated with baseline levels of glutamine in the thalamus.
Conclusions: Combining endogenous pain regulatory mechanisms with exogenous stimulation of the motor cortex can more effectively increase pain thresholds in healthy humans. Future studies should examine whether existing pain therapies may be enhanced with noninvasive brain stimulation and activation of DNIC. They should also assess whether brain metabolite levels can be utilized to predict clinical response to therapeutic interventions.
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Floyd, John Tyler. "Lower Extremity Transcranial Direct Current Stimulation (TDCS)| The Effect of Montage and Medium on Cortical Excitability." Thesis, University of Central Arkansas, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10686422.
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The dissertation consists of three parts. The first part is a systematic review of the literature regarding transcranial direct current stimulation (tDCS) and its effects on lower extremity motor behaviors and corticospinal excitability of the lower extremity representation of the motor cortex in healthy subjects. The second part investigates how different electrode montages and electrode conductance mediums affect corticospinal excitability of the tibialis anterior (TA) representation of the motor cortex in healthy subjects. The third part studies how different electrode montage and electrode conductance medium combinations affect ankle tracking accuracy in healthy subjects regarding the dominant lower extremity.
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Schwippel, Tobias Udo [Verfasser]. "The effect of transcranial direct current stimulation (tDCS) on working memory in schizophrenia / Tobias Udo Schwippel." Tübingen : Universitätsbibliothek Tübingen, 2020. http://d-nb.info/1218073756/34.
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Fonteneau, Clara. "Impact of a single frontal transcranial direct current stimulation on the dopaminergic network in healthy subjects." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1079/document.
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La stimulation transcrânienne par courant continu (tDCS) sert à moduler l’activité neuronale. Elle consiste à appliquer un faible courant constant entre deux électrodes placées sur le cuir chevelu. Deux montages semblent efficaces pour moduler les capacités cognitives et/ou soulager des symptômes cliniques. Cependant, les effets neurobiologiques de la tDCS sont encore mal connues. Ce travail de thèse a tenté de clarifier les mécanismes cérébraux de la tDCS chez les sujets sains, en particulier en lien avec le système dopaminergique. En utilisant un design randomisée en double aveugle, nous avons combiné une session de tDCS online avec plusieurs modalités d'imagerie (PET ou PET-IRM simultanée) chez le sujet au repos. Une première étude (n=32, 2mA, 20min) a montré que la tDCS bifrontale induit une augmentation de la dopamine extracellulaire dans le striatum ventral, impliqué dans le réseau de récompense-motivation, après la stimulation. Une seconde étude (n=30, 1mA, 30min) a montré que la tDCS fronto-temporale induit une augmentation de la dopamine extracellulaire dans la partie exécutive du striatum et une diminution de la perfusion dans une région du réseau du default mode (DMN), après la stimulation. L'analyse des données de cette étude est toujours en cours. Dans l’ensemble, ce travail fournit la preuve qu'une seule session de tDCS frontale peut impacter le système dopaminergique dans des régions connectées aux zones corticales stimulées. Par conséquent, les niveaux d'activité et réactivité dopaminergique doivent être de nouveaux éléments à considérer dans l’hypothèse globale de modulation de l’activité cérébrale par la tDCS frontaleTranscranial direct current stimulation (tDCS) is used to modulate neuronal activity in the brain. It consists in applying a small constant current between two electrodes placed over the scalp. Two frontal tDCS montages have shown promises in modulating cognitive abilities and/or helping to alleviate clinical symptoms. However, the effects of tDCS on brain physiology are still poorly understood. The aim of this thesis work was to clarify brain mechanisms underlying frontal tDCS in healthy subjects, specifically in relation to the dopaminergic system. Using a double blind sham-controlled design, we combined a single session of tDCS online with several imaging techniques (PET or simultaneous PET-MRI) with the subject at rest. A first study (n=32, 2mA, 20min) showed that bifrontal tDCS induced an increase in extracellular dopamine in the ventral striatum, involved in the reward-motivation network, after the stimulation period. A second study (n=30, 1mA, 30min) showed that fronto-temporal tDCS induced an increase in extracellular dopamine in the executive part of striatum as well as a decrease in perfusion in a region part of the default mode network (DMN), after the stimulation period. The data analysis of this study is still ongoing. Overall, the present work provides evidence that a single session of frontal tDCS impacts the dopaminergic system in regions connected to the stimulated cortical areas. Therefore, levels of dopamine activity and reactivity should be new elements to consider for a general hypothesis of brain modulation by frontal tDCS
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Frick, Barbara. "Nachweis von Veränderungen nicht-fokaler Neuroplastizität bei depressiven Patienten mittels transkranieller Gleichstromstimulation (transcranial direct current stimulation, tDCS)." Diss., Ludwig-Maximilians-Universität München, 2015. http://nbn-resolving.de/urn:nbn:de:bvb:19-184027.
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Jalali, Roya. "Investigating the neurobiological changes associated with cerebellar transcranial direct current stimulation (TDCS) using magnetic resonance imaging (MRI)." Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7661/.
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Anodal cerebellar transcranial direct current stimulation (tDCS) is known to enhance motor learning and it is suggested to hold promise as a therapeutic intervention. However, the neural mechanisms underpinning the effects of cerebellar tDCS are unknown. In addition, it is unclear whether this effect is robust across varying task parameters as if cerebellar tDCS is to be used clinically it must have a consistent effect across a relatively wide range of behaviours. Therefore, I performed four studies to address these questions. In the first three studies, I investigated the neural changes associated with cerebellar tDCS using magnetic resonance spectroscopy (MRS) and resting state functional magnetic resonance imaging (fMRI). My goal was to understand how cerebellar tDCS affected the metabolites within the cerebellum and functional connectivity between the cerebellum and distant brain areas. In addition, I wanted to understand if individual differences in how cerebellar tDCS influenced visuomotor adaptation could be explained by the effect tDCS had on neurobiology. Therefore, healthy participants underwent 3 sessions in which they received concurrent anodal cerebellar tDCS during visuomotor adaptation, MRS and resting state fMRI. I found that in 21% of participants cerebellar tDCS caused enhanced visuomotor adaptation, a decrease in GABA and increase in functional connectivity between the cerebellum and parietal cortex. This work suggests an ‘all-or-nothing’ type effect of cerebellar tDCS. In my final study, I examined the consistency of the cerebellar tDCS effect on visuomotor adaptation across a wide range of task parameters which were systematically varied. Each experiment examined whether cerebellar tDCS had a positive effect on adaptation when a unique feature of the task was altered. I found cerebellar tDCS to have an inconsistent effect on visuomotor adaptation. I conclude that such inconsistencies could be dependent on the amount of participants in each group that are receptive to cerebellar tDCS and suggest that at the very least it warrants substantially large sample size in cerebellar tDCS studies.
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Hoseini, Najmeh. "The effect of motor point associative stimulation (MPAS) and transcranial direct current stimulation (tDCS) on manual dexterity and sensorimotor neurophysiology." Thesis, Indiana University, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=3712436.
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Manual dexterity, the ability to manipulate objects with the hands, and the related position sense, or proprioception, are often impaired after stroke. Associative stimulation of motor points (MPAS) in hand muscles is known to modify motor cortex excitability and improve manual dexterity (McDonnell and Ridding, 2006).
However, it is not known whether the effect of this peripheral stimulation can be increased by central stimulation of sensorimotor cortex, in terms of function, proprioception, or cortical neurophysiology. Here we compare the functional and neurophysiological consequences of MPAS with and without transcranial direct current (tDCS) in healthy adults. MPAS was applied to two right hand muscles important for manual dexterity: APB and FDI. tDCS, a non-invasive brain stimulation technique, was simultaneously applied over left sensorimotor cortex. Both techniques stimulate motor as well as somatosensory pathways. Neurophysiological measures of motor cortex, including SICI (short intra-cortical inhibition), ICF (intracortical facilitation), and input/output (I/O) curve, were assessed with transcranial magnetic stimulation (TMS). Manual dexterity and proprioceptive acuity were also measured. 14 subjects completed 3 sessions of MPAS in combination with sham, anodal (excitatory) and cathodal (inhibitory) tDCS. 13 subjects completed 2 sessions of sham MPAS with sham or anodal tDCS. In combination with MPAS, anodal tDCS significantly increased the plateau of manual dexterity, increased cortical response to TMS, and tended to improve proprioceptive acuity compared to sham tDCS. The neural basis for the observed functional improvements may thus include somatosensory as well as motor cortex. Neither MPAS nor tDCS alone had any measurable effect. These results suggest that adding tDCS as a central intervention to complement peripheral MPAS may be a promising avenue of treatment for patients with impaired manual dexterity.
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Alizad, Vida. "Effects of transcranial direct current stimulation on gait in people with and without Parkinson's disease." Thesis, Queensland University of Technology, 2019. https://eprints.qut.edu.au/129454/1/Vida_Alizad_Thesis.pdf.
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This study was conducted to examine the effects of transcranial direct current stimulation (tDCS) on gait in people with and without Parkinson's disease. tDCS is a non-invasive brain stimulation, which uses weak direct current (1–2 mA) to the brain via electrodes applied on the skin of the scalp. The findings of this study provided future direction, particularly in terms of configuration of tDCS for gait improvement in people with PD and helped move the emerging brain stimulation approach to PD closer to clinical practice.
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Bachtiar, Velicia Elizabeth. "Transcranial stimulation of the human primary motor cortices." Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:0a0f5502-e07c-4d8c-bc04-10c0a1f107f3.
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The primary aim of this thesis is to investigate the physiological effects of transcranial direct current stimulation (tDCS) as applied to the primary motor cortex (M1). This research was largely motivated by the need to understand the basic physiological changes of tDCS, in order to evaluate its use as a potential tool in recovery after stroke, as well as its more general applicability as a tool to modulate plasticity. The experiments in this thesis assess the ability of tDCS to modulate the primary motor cortex in healthy controls. The effects of tDCS on cortical GABA and motor resting state functional connectivity were measured with magnetic resonance spectroscopy (MRS) and resting functional MRI (fMRI). Anodal stimulation reduced GABA concentration and increased functional connectivity in the stimulated M1. Testing these changes within the same individuals demonstrated that the magnitude of changes do not correlate across subjects. Novel evidence on the timecourse of GABA change demonstrated that the reduction in GABA is most prominent in the 30-minute period after stimulation. To determine whether the tDCS-induced modulations in inhibition is restricted to the stimulated hemisphere or whether inhibitory changes could be observed in the nonstimulated M1, or in the interhemispheric connections between the M1s, transcranial magnetic stimulation (TMS) was used to measure intracortical inhibition in each M1 and interhemispheric inhibition and facilitation in the contralateral M1. There were no polarity-specifc effects on intracortical inhibition within either M1, and no changes in interhemispheric excitability from the stimulated to non-stimulated M1. Development of a two-voxel MRS method at ultra high field (7 Tesla) allowed for concurrent measurements of cortical neurotransmitters from both M1s with excellent spectral quality and GABA quantifcation. This method was used to demonstrate the timecourse of tDCS-induced changes in neurochemicals concurrently from both M1s. Anodal stimulation reduced GABA in both the anode-targeted and non-stimulated M1. Cathodal stimulation decreased GABA and glutamate in the non-stimulated M1, with no concurrent changes in the cathode-targeted M1. Bilateral stimulation reduced glutamate in both M1 with no change in GABA.
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Bueno-Lopez, Ana [Verfasser]. "Effects of slow oscillatory transcranial direct current stimulation (so-tDCS) on sleep-dependent memory consolidation / Ana Bueno-Lopez." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2020. http://d-nb.info/1223928128/34.
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Kan, Benjamin. "Effect of transcranial direct current stimulation (tDCS) on maximal voluntary isometric strength and endurance of the elbow flexors." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2011. https://ro.ecu.edu.au/theses/375.
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The present study investigated the effects of transcranial direct current stimulation (tDCS) on maximal voluntary contraction strength (MVC) and the time to failure (TTF) of an isometric muscle endurance test of the elbow flexors. Prior to the main study, the test-retest reliability of MVC and TTF measures was investigated using 10 men (33.2 ± 9.4 y) for the measurements separated by 60 min (within-day) and one week (between-day). Coefficient of variation (CV), Intraclass correlation (ICC, R), a paired t-test and the Bland-Altman plots revealed that TTF at 30% MVC task was reliable, and was able to detect a possible effect of tDCS on TTF, if the magnitude of effect was greater than 11%. Based on the reliability study results, it was hypothesised that tDCS would increase TTF from the first test to the second test separated by 60 min, when a tDCS treatment was administered immediately before the second test. Fifteen men (27.7 ± 8.4 y) were tested for MVC and TTF at 30%-MVC before and immediately after tDCS or sham intervention (10 min) in three separate sessions. In two sessions direct current (2 mA) was delivered through saline-soaked sponge electrodes, with the anode placed on the scalp overlying the right motor cortical representation of the left arm and the cathode secured over the right shoulder. One session was a sham intervention (current delivery for the first 30s). The order of the intervention sessions was randomised and counterbalanced amongst the subjects and subjects who were blinded to intervention type. Changes in MVC strength and TTF from pre to post intervention were compared between the interventions by a two-way repeated measures ANOVA. No significant differences were evident for the two tDCS sessions. MVC strength (baseline: 66.0 ± 11.4 Nm) decreased by 5.9 ± 4.2 % (P
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Bryant, Andrew M. "Effects of Transcranial Direct Current Stimulation on Working Memory Performance in Older Adults: Potential Moderators." Ohio University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1595952473754039.
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Schiller, Christina. "Antidepressive Wirksamkeit der transkraniellen Gleichstromstimulation (transcranial direct current stimulation, tDCS) bei Patienten mit therapieresistenter Depression - Eine randomisierte, plazebokontrollierte Pilotstudie." Diss., lmu, 2012. http://nbn-resolving.de/urn:nbn:de:bvb:19-143542.
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Ironside, Maria. "An exploration of the mechanisms of action of transcranial direct current stimulation (tDCS) in mood and anxiety disorder research." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:5d331ccf-9922-4e67-8b53-a4a426ebe53d.
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The difficulty in treating mood and anxiety disorders has brought about renewed clinical interest in alternative treatments, such as transcranial direct current stimulation (tDCS) of the dorsolateral prefrontal cortex (DLPFC). However, the optimal parameters for stimulation and underlying mechanisms of action are unclear. Psychiatric treatments have acute effects on emotional processing which predict later therapeutic action. Such effects have been proposed as cognitive biomarkers for screening novel treatments for depression and anxiety disorders. In this thesis the proposed cognitive, behavioural and neural underpinnings of mood and anxiety disorders are explored using tDCS of the DLPFC in humans. This is investigated with a series of studies which measure the acute effects of tDCS on emotional processing relevant to depression and trait anxiety or anxiety disorders. An initial investigation in healthy volunteers revealed an anxiolytic like effect (reduced threat vigilance) of a single session of tDCS on a behavioural test of proven clinical relevance. In addition, stimulation parameters were refined for future studies. The subsequent two behavioural investigations combined tDCS with an attentional bias modification (ABM) training paradigm. However, no bias modification was achieved in these studies and predictably, no subsequent effects on attentional bias, mood/ trait anxiety or worry were observed. The first of the ABM investigations included a measure of cortisol awakening response (CAR) and it was found that a single session of tDCS (regardless of ABM condition) reduced subsequent CAR in healthy volunteers, also suggesting an anxiolytic effect. The final study, in a sample of trait anxious females, used functional imaging to reveal that tDCS of the DLPFC increased frontal activation and reduced amygdala response to fearful face distractors during low cognitive effort. This provides the first causal evidence that modulating activity directly in the DLPFC inhibits amygdala response to threat in humans, and provides a potential neural mechanism for the previous reduction in vigilance to threat, and also for the efficacy of tDCS in the treatment of depression and anxiety disorders. The evidence from this thesis puts forward an anxiolytic-like effect of frontal tDCS on cognitive, neural and adrenal biomarkers relevant to clinical anxiety disorders, and indicates a potential cognitive mechanism (reduced fear vigilance) and an underlying neural mechanism (increased top-down control of amygdala response) that may partially mediate the reported clinical efficacy of prefrontal tDCS in the literature.
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Fintescu, Zoe. "Einfluss der transkraniellen Gleichstrombehandlung (transcranial direct current stimulation, tDCS) auf kognitive Leistungen und BDNF-Serumkonzentrationen bei Patienten mit therapieresistenter Depression." Diss., lmu, 2011. http://nbn-resolving.de/urn:nbn:de:bvb:19-127227.
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Faehling, Florian Felix [Verfasser], and Christiann [Akademischer Betreuer] Plewnia. "Neurophysiological Correlates of the Modulation of Cognitive Control via Transcranial Direct Current Stimulation (tDCS) / Florian Felix Faehling ; Betreuer: Christiann Plewnia." Tübingen : Universitätsbibliothek Tübingen, 2018. http://d-nb.info/1168634490/34.
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Lommen, Jonathan Lyon Jacob. "Effects of Transcranial Direct-Current Stimulation on Gait Initiation in People with Parkinson’s Disease." Thesis, Université d'Ottawa / University of Ottawa, 2019. http://hdl.handle.net/10393/39959.
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Background: Gait initiation is a major issue in Parkinson’s disease (PD). Moreover, the effect of current treatment on motor deficits vary alongside individual differences and disease severity. In some cases, postural instability has been documented as a major side-effect and refractory symptom to dopaminergic medication. Despite these shortcomings, research involving other forms of therapy including deep brain stimulation (DBS) and transcranial magnetic stimulation (TMS), has evidenced the improvement of postural deficits in PD. In this regard, there is a strong rational for the modulation of subcortical brain activity via the application of non-invasive transcranial direct current stimulation (tDCS) to interconnected cortical brain structures. Purpose: Therefore, we sought to determine the effect of tDCS applied to the supplementary motor area (SMA), on gait initiation preparation and performance in PD. Methods: A within subjects repeated measures quasi-experimental design was used to investigate the effects of a 10-minute sham-controlled tDCS intervention. Clinically diagnosed participants (n=12) with idiopathic PD were tested on medication during two sessions that bookended one week. Those who had previously undergone other forms of brain stimulation, had diabetes, severe freezing of gait, or any other neurological or functional limitations that could interfere with gait initiation were excluded from the study. Statistical Analyses/Results: Two-way repeated measures ANOVAs with Bonferroni corrections and a post-hoc analyses when appropriate, revealed a significant reduction in the magnitude of center of pressure (CoP) displacement and velocity in the mediolateral (ML) direction following tDCS. Conclusions: Findings from this study provide insights that may guide scientific research regarding the effects of tDCS on gait initiation among those with PD. Additionally, our work may highlight the importance of ML postural stability for individuals with comorbid and/or pharmacologically induced postural instabilities.
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Harvey, Marie-Philippe. "Améliorer la douleur et le sommeil chez les aînés souffrant de douleur chronique à l’aide de la stimulation transcrânienne par courant direct (tDCS)." Mémoire, Université de Sherbrooke, 2016. http://hdl.handle.net/11143/9529.
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Résumé : Introduction: La douleur chronique et les problèmes de sommeil ont un impact significatif sur la qualité de vie. La prévalence de ces deux conditions augmente substantiellement avec l’âge. L’objectif de cette étude était d’évaluer la faisabilité d’une étude randomisée, contrôlée par placebo et de recueillir des données sur l’efficacité de la stimulation transcrânienne par courant direct (tDCS) pour réduire la douleur et améliorer le sommeil chez des aînés souffrant de douleur chronique d’origines musculo-squelettique. Méthodes: Quatorze patients souffrant de douleur chronique et de problèmes de sommeil ont reçu cinq séances quotidiennes consécutives de tDCS anodique appliquée au cortex moteur primaire (2 mA, 20 minutes) ou cinq séances de tDCS simulée de manière randomisée. L’intensité de la douleur était mesurée avec une échelle visuelle analogue et les paramètres de sommeil avec l’actigraphie. Pendant toute la durée de l’étude, des journaux de bord de douleur et de sommeil étaient aussi utilisés afin de mesurer l'effet de la tDCS sur la douleur et le sommeil du quotidien des participants. Résultats: Les résultats indiquent que la tDCS réelle engendre une analgésie de 59 %, alors que la tDCS simulée ne réduit pas la douleur (p < 0,05). Par contre, aucun changement n’a été observé au niveau des paramètres de sommeil (tous les p ≥ 0,18). Conclusion: Il appert que cinq séances de tDCS anodique appliquée au niveau du cortex moteur primaire seraient efficaces pour réduire la douleur des aînés souffrant de douleur chronique, mais pas pour améliorer leur sommeil. De futures études seront nécessaires afin de déterminer si d’autres paramètres de stimulation pourraient avoir un impact sur le sommeil et si ces résultats peuvent être reproduits en utilisant un plus grand nombre de patients.Abstract : Introduction: Chronic pain and sleep problems have a significant impact on quality of life. The prevalence of these two conditions increases substantially with age. The objective of this study was to assess the feasibility of conducting a randomized sham-controlled trial and to collect preliminary data on the efficacy of transcranial direct current stimulation (tDCS) for reducing pain and improving sleep in older adults suffering from chronic musculoskeletal pain. Methods: Fourteen patients with chronic pain and sleep problems were randomized to receive five consecutive daily sessions of anodal tDCS applied to the primary motor cortex (2 mA, 20 minutes) or five sessions of sham tDCS. Pain intensity was measured with a visual analogue scale, and sleep parameters with actigraphy. Throughout the study, pain and sleep logbook were also used to measure the effect of tDCS on daily pain and sleep. Results: Our results indicate that the real tDCS causes greater pain relief than sham tDCS (59 % vs -19 %; p <0.05). By cons, no change was observed in sleep parameters (all p ≥ 0.18). Conclusion: Five sessions of anodal tDCS applied to the motor cortex seem to be effective to reduce pain in elderly individuals suffering of chronic pain, but not to improve their sleep. Future studies are needed to determine whether other stimulation parameters could have an impact on sleep and whether these results can be replicated using a larger number of patients.
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Asthana, Manish [Verfasser], and Martin J. [Akademischer Betreuer] Herrmann. "Associative learning – Genetic modulation of extinction and reconsolidation and the effects of transcranial Direct Current Stimulation (tDCS) / Manish Asthana. Betreuer: Martin J. Herrmann." Würzburg : Universitätsbibliothek der Universität Würzburg, 2013. http://d-nb.info/1045153095/34.
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Elsner, Bernhard, Gert Kwakkel, Joachim Kugler, and Jan Mehrholz. "Transcranial direct current stimulation (tDCS) for improving capacity in activities and arm function after stroke: a network meta-analysis of randomised controlled trials." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-232467.
Full textAbstract:
Background:
Transcranial Direct Current Stimulation (tDCS) is an emerging approach for improving capacity in activities of daily living (ADL) and upper limb function after stroke. However, it remains unclear what type of tDCS
stimulation is most effective. Our aim was to give an overview of the evidence network regarding the efficacy and safety of tDCS and to estimate the effectiveness of the different stimulation types.
Methods:
We performed a systematic review of randomised trials using network meta-analysis (NMA), searching the following databases until 5 July 2016: Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, CINAHL, AMED, Web of Science, and four other databases. We included studies with adult people with stroke. We compared any kind of active tDCS (anodal, cathodal, or dual, that is applying anodal and cathodal tDCS concurrently) regarding improvement of our primary outcome of ADL capacity, versus control, after stroke.
PROSPERO ID: CRD42016042055.
Results:
We included 26 studies with 754 participants. Our NMA showed evidence of an effect of cathodal tDCS in improving our primary outcome, that of ADL capacity (standardized mean difference, SMD = 0.42; 95% CI 0.14 to 0.70). tDCS did not improve our secondary outcome, that of arm function, measured by the Fugl-Meyer upperextremity assessment (FM-UE). There was no difference in safety between tDCS and its control interventions, measured by the number of dropouts and adverse events.
Conclusion:
Comparing different forms of tDCS shows that cathodal tDCS is the most promising treatment option to improve ADL capacity in people with stroke.
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Elsner, Bernhard, Gert Kwakkel, Joachim Kugler, and Jan Mehrholz. "Transcranial direct current stimulation (tDCS) for improving capacity in activities and arm function after stroke: a network meta-analysis of randomised controlled trials." BioMed Central, 2017. https://tud.qucosa.de/id/qucosa%3A30748.
Full textAbstract:
Background:
Transcranial Direct Current Stimulation (tDCS) is an emerging approach for improving capacity in activities of daily living (ADL) and upper limb function after stroke. However, it remains unclear what type of tDCS
stimulation is most effective. Our aim was to give an overview of the evidence network regarding the efficacy and safety of tDCS and to estimate the effectiveness of the different stimulation types.
Methods:
We performed a systematic review of randomised trials using network meta-analysis (NMA), searching the following databases until 5 July 2016: Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, CINAHL, AMED, Web of Science, and four other databases. We included studies with adult people with stroke. We compared any kind of active tDCS (anodal, cathodal, or dual, that is applying anodal and cathodal tDCS concurrently) regarding improvement of our primary outcome of ADL capacity, versus control, after stroke.
PROSPERO ID: CRD42016042055.
Results:
We included 26 studies with 754 participants. Our NMA showed evidence of an effect of cathodal tDCS in improving our primary outcome, that of ADL capacity (standardized mean difference, SMD = 0.42; 95% CI 0.14 to 0.70). tDCS did not improve our secondary outcome, that of arm function, measured by the Fugl-Meyer upperextremity assessment (FM-UE). There was no difference in safety between tDCS and its control interventions, measured by the number of dropouts and adverse events.
Conclusion:
Comparing different forms of tDCS shows that cathodal tDCS is the most promising treatment option to improve ADL capacity in people with stroke.
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Schneider, Caroline [Verfasser], Martin J. [Gutachter] Herrmann, Marcel [Gutachter] Romanos, and Philip [Gutachter] Tovote. "Modulation der Extinktion einer konditionierten Furchtreaktion durch Stimulation des präfrontalen Kortex mittels tDCS (transcranial direct current stimulation) / Caroline Schneider ; Gutachter: Martin J. Herrmann, Marcel Romanos, Philip Tovote." Würzburg : Universität Würzburg, 2020. http://d-nb.info/1215033885/34.
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Kennerly, Richard C. "Changes in Quantitative EEG and Low Resolution Tomography Following Cranial Electrotherapy Stimulation." Thesis, University of North Texas, 2006. https://digital.library.unt.edu/ark:/67531/metadc5364/.
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The effects of cranial electrotherapy stimulation (CES) on human EEG and brain current density were evaluated by quantitative electroencephalography (qEEG) and low resolution brain electromagnetic tomography (LORETA). A total of 72 research subjects were provided with a single session of CES, 38 were provided with 0.5 Hz CES while 34 were provided with 100 Hz CES. The qEEG paired t-tests revealed that in both frequencies of CES there was a significant (.05) increase in alpha relative power with concomitant decreases in delta and beta relative power. The 0.5 Hz CES decreased a wider frequency range of delta activity, while the 100 Hz CES decreased a wider frequency range of beta activity; suggesting some difference may exist in the EEG response to different frequencies of CES. The changes found in qEEG relative power were consistent with the affective and cognitive effects of CES reported in the literature, such as increased relaxation and decreased anxiety. Statistically significant changes for qEEG values other than relative power, such as coherence, amplitude asymmetry, phase lag and power ratios were also found. The LORETA paired t-tests found statistically significant (.05) increases in cortical and subcortical theta and alpha frequency current density with concomitant decreases in delta and beta current density. The effects of CES on current density varied by frequency, but did not show a differential in response based on proximity to the contacts, or structures within the brain. Statistically significant changes in current density were found in all 2394 gray matter voxels represented by LORETA, indicating a whole brain response to the CES stimulus. The qEEG and LORETA findings revealed that a single 20-minute session of CES does have a significant effect on the cortical and subcortical activity of the human brain resulting in activity consistent with decreased anxiety and increased relaxation.
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Schiller, Christina [Verfasser], and Frank [Akademischer Betreuer] Padberg. "Antidepressive Wirksamkeit der transkraniellen Gleichstromstimulation (transcranial direct current stimulation, tDCS) bei Patienten mit therapieresistenter Depression : eine randomisierte, plazebokontrollierte Pilotstudie / Christina Schiller. Betreuer: Frank Padberg." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2012. http://d-nb.info/102320598X/34.
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Frick, Barbara [Verfasser], and Frank [Akademischer Betreuer] Padberg. "Nachweis von Veränderungen nicht-fokaler Neuroplastizität bei depressiven Patienten mittels transkranieller Gleichstromstimulation (transcranial direct current stimulation, tDCS) : eine Pilotstudie / Barbara Frick. Betreuer: Frank Padberg." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2015. http://d-nb.info/1074825446/34.
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Rabipour, Sheida. "Effects of Expectations on Cognitive Enhancement Interventions in Young and Older Adults." Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/38157.
Full textAbstract:
With increasing life expectancy and global population of older adults, preserving cog- nitive function throughout life represents a growing priority. Numerous approaches to cognitive enhancement exist, but few have scientific merit. Among the most preva- lent – and commercialized – approaches are cognitive training (“brain training”) and non-invasive brain stimulation through electric currents applied at the surface of the scalp. The present dissertation describes a collection of work contextualizing the appeal of these cognitive enhancement methods and addressing some of the most pervasive limitations of research in this field thus far.
One largely ignored issue in cognitive intervention research pertains to people’s expectations of programs and their relationship with intervention outcomes. In a series of initial studies, we developed and validated the Expectation Assessment Scale (EAS), a tool created to measure as well as prime expectations of outcomes in the context of cognitive enhancement interventions. In our first two studies, we probed expectations of cognitive training or non-invasive brain stimulation in over 1,000 young, middle-aged, and older adults. Ratings on the EAS suggested that older adults may have particularly high expectations of cognitive training, but that expectations can be primed to increase or decrease – at least in hypothetical scenarios. We used these data to assess the psychometric properties of the EAS with item-response theory, and confirmed its internal consistency.
Next, we incorporated the EAS into two cognitive enhancement trials, one in- vestigating a computerized cognitive training intervention in nearly 100 older adults and another examining non-invasive brain stimulation in nearly 100 young adults. Both trials had a double-blind balanced-placebo design in which participants were assigned to the intervention or control condition, and then subdivided to receive ei- ther high or low expectation priming (i.e., primed to have high or low expectations of the program’s effectiveness). Although expectation ratings replicated our previous findings, results from these trials suggest little, if any, effect of either expectations or the intervention on performance outcomes. We nevertheless found that participants enjoyed their assigned program and that those who received high expectation prim- ing tended to report a more positive experience. Our findings put into question the effectiveness of such interventions and support the need for more rigorous trials of cognitive enhancement.
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Huang, Austin. "Cortical Stimulation Mapping of Heschl’s Gyrus in the Auditory Cortex for Tinnitus Treatment." Scholarship @ Claremont, 2019. https://scholarship.claremont.edu/cmc_theses/2073.
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Tinnitus is the perception of sound in the absence of an actual sound stimulus. Recent developments have shifted the focus to the central nervous system and the neural correlate of tinnitus. Broadly, tinnitus involves cortical map rearrangement, pathological neural synchrony, and increased spontaneous firing rates. Various cortical regions, such as Heschl’s gyrus in the auditory cortex, have been found to be associated with different aspects of tinnitus, such as perception and loudness. I propose a cortical stimulation mapping study of Heschl’s gyrus using a depth and subdural electrode montage to conduct electrocorticography. This study would provide high-resolution data on abnormal frequency band oscillations characteristic of tinnitus and pinpoint regions where they occur. The validity of the neural synchrony model would also be tested in this study.
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Caytak, Herschel Binyomin. "Bioimpedance Spectroscopy Methods for Analysis and Control of Neurostimulation Dose." Thesis, Université d'Ottawa / University of Ottawa, 2019. http://hdl.handle.net/10393/38629.
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TDCS is a form of non-invasive neurostimulation that is comprised of injection of current via strategically placed scalp electrodes into targeted areas of the brain. TDCS has shown therapeutic benefit for numerous clinical applications. This technique has not however been widely adopted due to high variability of response to the stimulation. Current state of the art methods for optimizing tDCS are based on FEM models that generally model tissue as isotropic and homogeneous and do not take into account inter subject variability of head tissue electrical properties. We therefore develop an in-vivo method of measuring and analyzing bioimpedance spectroscopy measurements of the head to estimate change to tDCS dose in neural tissues for different subjects.
Finite element simulations are implemented on a realistic MRI derived head model. 5\% random Gaussian noise is added. Experimental bioimpedance measurements are taken of the heads of 8 subjects.
We simulate sensitivity distribution and impedance for a variety of 2 and 4 electrode configurations over a wide frequency range. We also extract Cole parameters and implement PCA on simulated and experimental impedance.
We demonstrate that the Cole model of the head can be accurately
approximated by the sum in series of Cole systems of each tissue. Comparison of Cole parameters from various simulated electrode configurations show statistical differences (paired t test $p<.05$). PCA shows that close to 100\% of the variance between two impedance spectra is described along a single principal component. Variation described by the second principal component increases as a function of increasing inter electrode gap which may be related to changes in dose. FEM and experimentally derived Cole parameters show different trends for various electrode configurations, good agreement is however shown for the PCA results.
The outcome of this research may lead to a higher tDCS efficacy by improving standardization and control of stimulation by relation of dose and bioimpedance spectra characteristics.
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Chalah, Moussa. "Physiopathologie et traitement de la fatigue dans la sclérose en plaques Fatigue in multiple sclerosis - Insights into evaluation and management Effects of left DLPFC versus right PPC tDCS on multiple sclerosis fatigue Long-term effects of tDCS on fatigue, mood and cognition in multiple sclerosis Long term effects of prefrontal tDCS on multiple sclerosis fatigue: A case study Transcranial direct current stimulation: A glimmer of hope for multiple sclerosis fatigue? Neurophysiological, radiological and neuropsychological evaluation of fatigue in multiple sclerosis Corticospinal inhibition and alexithymia in multiple sclerosis patients–An exploratory study." Thesis, Paris Est, 2019. http://www.theses.fr/2019PESC0066.
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La fatigue est un symptôme fréquent chez les patients atteints de sclérose en plaques (SEP). Malgré la gravité de ce symptôme, sa physiopathologie demeure vague et ses traitements sont insatisfaisants dans la majorité des cas. L’objectif de ce travail était de comprendre les mécanismes sous-jacents de la fatigue liée à la SEP, et tester les effets de la stimulation électrique transcrânienne (tDCS) sur ce symptôme. Dans une première étude (revue de littérature), on a analysé les données disponibles sur la physiopathologie de la fatigue dans la SEP, et on a identifié une boucle cortico-striato-thalamo-corticale associée à ce symptôme. On a trouvé que, sur le plan neuropsychologique, les symptômes affectifs sont les corrélats les plus pertinents. Cependant, les corrélats neurophysiologiques de ce symptôme sont peu étudiés et une discordance existe dans la littérature quant aux résultats rapportés par les divers travaux. Ensuite, dans une deuxième étude, on a effectué une évaluation physiopathologique de la fatigue chez 38 patients atteints de SEP. Les patients fatigués avaient, par rapport à ceux non fatigués, une symptomatologie affective plus prononcée, une inhibition intracorticale plus élevée et des anomalies cortico-sous-corticales touchant les noyaux caudés et le cortex pariétal. Les résultats neuropsychologiques de ce travail suggèrent des mécanismes sous-jacents communs ainsi que des relations bidirectionnelles entre la fatigue et les symptômes affectifs. Les résultats neurophysiologiques reflètent des processus de plasticité mal adaptative à l’origine de la fatigue. Les résultats radiologiques soutiennent la présence d’une boucle cortico-sous-corticale à la base de la perception de la fatigue dans la SEP. Dans une troisième étude, on s’est intéressé à étudier, chez 27 patients, la neurophysiologie des symptômes affectifs associés à la fatigue dans la SEP. Une association significative a été observée entre l'alexithymie et la période de silence corticale. Les résultats mettent en évidence la relation entre l'alexithymie et une transmission gabaergique défectueuse, et concordent avec des travaux antérieurs réalisés chez des sujets sains et des patients souffrant de troubles de la personnalité. Dans une quatrième étude, on a effectué une revue de la littérature sur la place de la tDCS dans le traitement de la fatigue de la SEP, et on a identifié quelques travaux qui ont rapporté des résultats prometteurs obtenus en réponse à une stimulation anodique des régions sensorimotrices. Ensuite, dans une cinquième étude, on a évalué la place de la tDCS anodique préfrontale gauche ou pariétale droite dans le traitement de la fatigue liée à la SEP. 10 patients fatigués atteints de SEP ont été inclus dans une étude croisée randomisée contrôlée en double aveugle (stimulation anodique réelle ou placebo ciblant le cortex préfrontal gauche ou pariétal droit). Seule la stimulation active préfrontale gauche s’est avérée efficace sur la fatigue. Enfin, du fait de la possibilité de prolonger et de potentialiser les effets en multipliant les séances de stimulation, on a appliqué dans une dernière étude, 14-19 séances de tDCS anodique préfrontale gauche chez deux patients ; cette intervention a permis de maintenir, sur plusieurs semaines, les effets bénéfiques de la tDCS sur la fatigue et améliorer d’autres mesures cognitives et affectives. Compte tenu du caractère handicapant de la SEP, des projets futurs pourraient tester l’application de la tDCS à domicile, avec un outil de stimulation bien sécurisé et un contrôle technique supervisé à distance afin de s’assurer du bon déroulement des séances et maximiser les bénéfices. Aussi, un couplage de la tDCS à des techniques de psychothérapie, notamment la thérapie cognitivo-comportementale, semble avoir une place dans l’arsenal thérapeutique de ce symptôme et mérite d’être évalué dans l’avenir procheFatigue is a common symptom that dramatically affects the quality of life of patients with multiple sclerosis (MS). Despite the severity of this symptom, its pathophysiology remains vague and diverse, and its available treatments are unsatisfactory in the majority of cases. The aim of this work was to understand the underlying mechanisms of fatigue in MS, and then to conduct a therapeutic study to assess the effects of transcranial direct current stimulation (tDCS) on fatigue in MS patients.In a first study (literature review), the available data on the pathophysiology of fatigue in MS were analyzed, and a cortico-striato-thalamo-cortical loop associated with this symptom was identified. Affective symptoms constitute the most pertinent neuropsychological correlates. Neurophysiological data are scarce and inconsistent across the studies. Then, in a second study, a multidisciplinary assessment of fatigue was performed in 38 MS patients. Compared to non-fatigued patients, fatigued ones had higher scores of affective symptoms; higher intracortical inhibition; and cortico-subcortical abnormalities (caudate nuclei and parietal cortex). The neuropsychological findings suggest common underlying mechanisms as well as bidirectional relationships between fatigue and affective symptoms. The neurophysiological findings may reflect maladaptive plasticity processes behind the generation of fatigue. The radiological findings support the existence of a cortico-subcortical loop at the basis of MS fatigue. In a third study, the neurophysiology of affective symptoms associated with MS fatigue was assessed in 27 patients. A significant association was found between alexithymia and the cortical silent period. These results highlight the relationship between alexithymia and defective GABAergic transmission and are consistent with previous work in healthy subjects and patients with personality disorders.In a fourth study, a literature review was conducted on the use of tDCS to treat MS fatigue, and a few studies targeting the sensorimotor regions, and yielding promising antifatigue effects were identified. In a fifth study, the place of anodal prefrontal or parietal tDCS in the treatment of fatigue was assessed in 10 fatigued MS patients in a crossover randomized controlled double-blind study (active or sham anodal tDCS over the left prefrontal or right parietal cortex). Only active left prefrontal stimulation improved fatigue. This work proposes tDCS as a potential therapeutic tool for treating MS fatigue. Finally, based on recent literature supporting the idea of a cumulative effect following the repetition of stimulation sessions, several sessions of left prefrontal anodal tDCS (14-19 sessions) were performed in two patients; this intervention led to a long-term improvement of fatigue as well as an amelioration of other cognitive and affective manifestations.Since MS is a debilitating disease, future projects could test the application of home-based tDCS using a well-secured stimulation setting and a remotely supervised technical control in order to ensure a successful session performance and maximize the clinical benefits. In addition, coupling tDCS with some psychotherapeutic approaches, notably the cognitive-behavioral therapy, could have a place in the therapeutic armamentarium of MS fatigue and merits in-depth assessment in the near future
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Bation, Rémy. "Stimulation électrique par courant continu (tDCS) dans les Troubles Obsessionnels et Compulsifs résistants : effets cliniques et électrophysiologiques." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1344/document.
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Les Troubles Obsessionnels et Compulsifs (TOC) sont un trouble mental sévère et fréquemment résistant. La physiopathologie du trouble se caractérise par des anomalies au sein des boucle cortico-striato-thalamo-cortical entrainant une hyper-activité du cortex orbito-frontal, du cortex cingulaire antérieur, du putamen. Au cours des dernières années, des anomalies structurales et fonctionnelles du cervelet ont de plus été mise en évidence dans les TOC venant compléter le modèle existant.Nous avons mise au point un protocole de traitement par tDCS ciblant le cortex orbito-frontal gauche et le cervelet droit pour les TOC résistants. Dans une première étude, nous avons étudié la faisabilité de ce protocole de traitement dans une étude ouverte. Cette étude a mis en évidence une réduction significative des symptômes dans une population de patient à haut niveau de résistance. Dans une deuxième étude, nous avons évaluer l’effet de ce traitement dans un protocole randomisé, contrôlé et parallèle contre placebo. Cette étude n’a pas confirmé l’efficacité de ce protocole de traitement. Dans cette même population, nous avons au cours du protocole mesuré les paramètres d’excitabilité corticale au niveau du cortex moteur par stimulation magnétique transrânienne. Nous avons ainsi mis en évidence que la tDCS provoquait une augmentation significative des processus d’inhibition (Short Interval Cortical Inhibition : SICI ) et une diminution non significative des processus de facilitation (Intra Cortical Facilitation : ICF). L’étude des effets cliniques et électro-physiologiques de cette approche thérapeutique novatrice dans les TOC résistants n’a pas permis de confirmer son intérêt clinique malgré un impact de ce protocole sur les modifications de l’excitabilité corticale inhérentes aux troubles. Ces données ont été mise en relation avec la littérature afin de proposer des perspectives d’évolution dans l’utilisation de la tDCS dans les TOC résistantsObsessive-compulsive disorder (OCD) is a severe mental illness. OCD symptoms are often resistant to available treatments. Neurobiological models of OCD are based on an imbalance between the direct (excitatory) and indirect (inhibitory) pathway within this cortico-striato-thalamo-cortical loops, which causes hyperactivation in the orbito-frontal cortex, the cingular anterior cortex, the putamen. More recently, the role of cerebellum in the OCD physiopathology has been brought to light by studies showing structural and functional abnormalities. We proposed to use tDCS as a therapeutic tool for resistant OCD by targeting the hyperactive left orbito-frontal cortex with cathodal tDCS (assumed to decrease cortical excitability) coupled with anodal cerebellar tDCS. In a first study, we studied the feasibility of this treatment protocol in an open-trial. This study found a significant reduction in symptoms in a population with a high level of resistance. In a second study, we evaluated the effect of this treatment in a randomized-controlled trial. This study did not confirm the effectiveness of this intervention. We have assessed motor cortex cortical excitability parameters by transcranial magnetic stimulation. We thus demonstrated that the tDCS caused a significant increase of inhibition processes (Short Interval Cortical Inhibition: SICI) and a nonsignificant decrease in the facilitation processes (Intra Cortical Facilitation (ICF)). In addition, clinical improvement assessed by Clinical Global Impression at the end of the follow-up period (3 months) was positively correlated with SICI at baseline.tDCS with the cathode placed over the left OFC combined with the anode placed over the right cerebellum decreased hyper-excitability in the motor cortex but was not significantly effective in SSRI- resistant OCD patients. These works were discussed in light of the available literature to create future prospect in the field of tDCS treatment for OCD resistant patients
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Soares, Foerster Aguida [Verfasser], Michael [Akademischer Betreuer] Nitsche, André [Gutachter] Niklas, and Siegmar [Gutachter] Blumentritt. "Optimization of transcranial direct current stimulation (tDCS) to modulate lower limb motor network in healthy humans / Aguida Soares Foerster ; Gutachter: André Niklas, Siegmar Blumentritt ; Betreuer: Michael Nitsche." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2018. http://d-nb.info/1166670805/34.
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Duarte, Natália de Almeida Carvalho. "Efeito da estimulação transcraniana por corrente contínua associada ao treino de marcha sobre o equilíbrio e o desempenho funcional de crianças com paralisia cerebral: ensaio clínico controlado aleatorizado e duplo cego." Universidade Nove de Julho, 2015. http://bibliotecadigital.uninove.br/handle/tede/1342.
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The goal of this study was to Investigate the effects of transcranial direct current stimulation in the primary motor cortex, associated with gait training on balance and functional performance of children with cerebral palsy (CP). The sample population that was part of this project consisted of 24 children with CP between five and ten years old. Children were be randomly allocated into two groups (Group 1: gait training on the treadmill with transcranial stimulation activates, Group 2: gait training on the treadmill with transcranial stimulation placebo) and evaluated at three different times (pre-intervention, immediately after and one month after the proposed training). The evaluation consisted of the quantification of static balance, functional balance (Pediatric Balance Scale) and functional performance (Inventory assessment of pediatric disorders). The trainings was done for two consecutive weeks, with five training sessions per week, for 20 minutes per session. The transcranial stimulation and treadmill training was realized simultaneously, in each session during twenty minutes, with an intensity of 1 mA. The results were statistically analyzed assuming a significance level of 0.05 (p < 0.05). The experimental group exhibited better results in comparison to the control group with regard to anteroposterior sway (eyes open and closed; p,0.05), mediolateral sway (eyes closed; p,0.05) and the Pediatric Balance Scale both one week and one month after the completion of the protocol. Gait training on a treadmill combined with anodal stimulation of the primary motor cortex led to improvements in static balance and functional performance in children with cerebral palsy.
O objetivo do estudo foi verificar os efeitos da estimulação transcraniana por corrente contínua no córtex motor primário, associada ao treino de marcha sobre o equilíbrio e desempenho funcional de crianças com paralisia cerebral (PC). A amostra populacional que fez parte deste projeto foi composta de 24 crianças com PC entre cinco a dez anos de idade. As crianças foram alocadas randomicamente em dois grupos (Grupo 1: treino de marcha na esteira com estimulação transcraniana ativa; Grupo 2: treino de marcha na esteira com estimulação transcraniana placebo) e avaliadas em três momentos distintos (pré intervenção, logo após e um mês após o treino proposto). A avaliação foi constituída da quantificação do equilíbrio estático, do equilíbrio funcional (Escala de equilíbrio pediátrica) e do desempenho funcional (Inventário de avaliação pediátrica de disfunções). Os treinos foram realizados durante duas semanas consecutivas, com cinco sessões de treino por semana com duração de 20 minutos por sessão. A estimulação transcraniana foi realizada simultâneamente ao treino de marcha em esteira, em cada sessão durante vinte minutos, com uma intensidade de 1 mA. Os resultados foram analisados estatisticamente assumindo um nível de significância de 0,05 (p<0,05). O grupo experimental apresentou melhores resultados quando comparado ao grupo controle em relação ao balanço anteroposterior (olhos abertos e olhos fechados), ao balanço mediolateral (olhos fechados) e na escala de equilíbrio pediátrica, uma semana e um mês após o término do protocolo. O treino de marcha em esteira associado com a estimulação anódica sobre o córtex motor primário causou melhoras no equilíbrio estático e funcional de crianças com paralisia cerebral.
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Ladeira, Andrea. "Investigaçăo sobre o impacto da estimulaçăo transcraniana por corrente contínua em tarefa de resoluçăo temporal por meio da prova RGDT - Random Gap Detection Test." Universidade Presbiteriana Mackenzie, 2009. http://tede.mackenzie.br/jspui/handle/tede/1712.
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Previous issue date: 2009-01-22Fundo Mackenzie de Pesquisa
The Central Auditory Processing Disorders are the deficiency of one or more hearing processes and mechanisms or the deficiency of major dysfunctions. Considering that new therapeutic and/or diagnostic approaches should be investigated, recent studies have shown that non invasive cerebral stimulation tools are efficient in the modulation of brain activity in a safe and painless way. One of these techniques is the Transcranial Direct Current Stimulation (TDCs). TDCs studies have shown that this technique is able to modulate cortical excitability on visual and motor areas and it is also capable to interfere in task performance involving cognitive functions on pre-frontal cortex such as operational memory and decision making. The aim of this study was the investigation of the possible effects of TDCs on primary auditory cortex, on temporal resolution tasks, using RGDT (Random Gap Detection Test). Eleven healthy volunteers received anodal, cathodal bilateral or sham ETCC in alternate days (i=2mA) and RGDT test was carried out before and during stimulation. It has been observed a significant effect for the frequencies of 4000Hz, Averages of Frequencies and Clicks, with an increase in the capacity of temporal discrimination in anodal stimulation and reduction in cathodal stimulation conditions. This is the first study showing that the ETCC of low intensity is capable of modulating the activity of primary auditory cortex resulting in positive or negative impact in the performance in task of temporal resolution according to the applied polarity (anodal or cathodal, respectively). Not only is the impact of these results in the demonstration of the TDCs as an important tool of investigation in cognitive neuroscience, but also in its use as an intervention tool. New studies will be necessary to investigate the impact of the TDCs in patients with alterations of the central auditory processing.
Os transtornos do Processamento Auditivo Central são caracterizados pela deficiência de um ou mais processos e mecanismos da audição ou são deficiências originadas de disfunções maiores. Considerando que novas abordagens terapêuticas e/ou diagnósticas devem ser investigadas, estudos recentes têm demonstrado que ferramentas de estimulação cerebral não invasivas são eficazes em modular a atividade cerebral de forma indolor e segura. Uma dessas técnicas é a Estimulação Transcraniana por Corrente Contínua (ETCC). Estudos realizados com ETCC têm demonstrado que esta técnica modula a excitabilidade cortical de áreas motoras e visuais e, além disso, é capaz de interferir no desempenho de tarefas que envolvam funções cognitivas como memória operacional e tomada de decisão quando aplicada em córtex pré-frontal. Este estudo teve como objetivo investigar os possíveis efeitos da ETCC em área cortical auditiva primária, em avaliação de tarefas de resolução temporal auditiva, utilizando o teste Random Gap Detection Test (RGDT). 11(onze) voluntários saudáveis receberam em dias alternados ETCC bilateral anódica, catódica ou placebo (i=2mA) e realizaram o teste RGDT antes e durante a estimulação. Observou-se um efeito significativo para as freqüências de 4000Hz, Médias de Freqüências e Clicks, com aumento na capacidade de discriminação temporal em condição de estimulação anódica e redução em estimulação catódica. Este é o primeiro estudo mostrando que a ETCC de baixa intensidade é capaz de modular a atividade do córtex auditivo primário resultando em impacto positivo ou negativo no desempenho em tarefa de resolução temporal em função da polaridade aplicada (ânodo ou cátodo, respectivamente). O impacto desses resultados reside na demonstração de que a ETCC é uma importante ferramenta de investigação em neurociência cognitiva, mas que também pode ter desdobramentos como ferramenta de intervenção. Novos estudos serão necessários para investigar o impacto da ETCC em pacientes com alterações de processamento auditivo central.
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Williams, Petra S. "Neural Mechanisms of Task Failure During Sustained Submaximal Contractions." Ohio University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1367330801.
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Frangou, Polytimi. "Inhibitory mechanisms for visual learning in the human brain." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/280767.
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Identifying targets in cluttered scenes is critical for our interactions in complex environments. Our visual system is challenged to both detect elusive targets that we may want to avoid or chase and discriminate between targets that are highly similar. These tasks require our visual system to become an expert at detecting distinctive features that help us differentiate between indistinguishable targets. As the human brain is trained on this type of visual tasks, we observe changes in its function that correspond to improved performance. We use functional brain imaging, to measure learning-dependent modulations of brain activation and investigate the processes that mediate functional brain plasticity. I propose that dissociable brain mechanisms are engaged when detecting targets in clutter vs. discriminating between highly similar targets: for the former, background clutter needs to be suppressed for the target to be recognised, whereas for the latter, neurons are tuned to respond to fine differences. Although GABAergic inhibition is known to suppress redundant neuronal populations and tune neuronal representations, its role in visual learning remains largely unexplored. Here, I propose that GABAergic inhibition plays an important role in visual plasticity through training on these tasks. The purpose of my PhD is to investigate the inhibitory mechanisms that mediate visual perceptual learning; in particular, learning to detect patterns in visual clutter and discriminate between highly similar patterns. I show that BOLD signals as measured by functional Magnetic Resonance Imaging (fMRI) do not differentiate between the two proposed mechanisms. In contrast, Magnetic Resonance Spectroscopy (MRS) provides strong evidence for the distinct involvement of GABAergic inhibition in visual plasticity. Further, my findings show GABA changes during the time-course of learning providing evidence for a distinct role of GABA in learning-dependent plasticity across different brain regions involved in visual learning. Finally, I test the causal link between inhibitory contributions and visual plasticity using a brain stimulation intervention that perturbs the excitation-inhibition balance in the visual cortex and facilitates learning.
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Araujo, Ricardo Rafael de. "Modulação da orientação temporal e espacial da atenção por meio de estimulação transcraniana por corrente contínua." Universidade Presbiteriana Mackenzie, 2011. http://tede.mackenzie.br/jspui/handle/tede/1548.
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Previous issue date: 2011-02-25Fundo Mackenzie de Pesquisa
Attention can be understood as a set of neural mechanisms that enhance the processing of relevant information, thoughts or actions while ignoring irrelevant or scattered stimuli. Thus, attention allows the organism to interact in a proper way with the environment. Among the brain structures associated with the control of attention, the Dorsolateral Prefrontal Cortex (DLPFC) has a remarkable role in current literature as a region associated with behavioral control. Transcranial Direct Current Stimulation (TDCS) is based on the application of a low intensity electric current through electrodes placed in the scalp, aimed at modulating the activity of different brain areas. This technique has been used to study brain functions. This study has the objective of verifying how attention can be modulated through the application of bilateral tDCS on DLPFC using measures of reaction time (RT) in tasks of temporal and spatial orientation. To accomplish that, two experiments were planned and executed. In the first one, which focused on the voluntary orienting of spatial attention, each participant had to orient attention to the position indicated by an arrow; in the second, on voluntary orienting of temporal attention, each participant had to orient attention to the most frequent time interval of visual targets. In both cases, participants had to respond as fast as possible when the target was displayed by pressing a joystick key. RTs were registered. The sample was composed of 18 undergraduate students, age range 19-25 years old (12 for the first experiment and 6 more for the second). In each experiment, subjects were submitted to three tDCS conditions (anodal, cathodal and sham) on the DLPFC during the undertaking of tests. Analyses of variance were made, in order to compare the involved factors. For the experiment of spatial orientation, the anodal condition produced lower RTs, when compared to sham. For the temporal orienting experiment it was observed that, in the anodal modulation, RTs were increased for the less frequent interval (500 ms), indicating that the anodal tDCS can have influenced in a more effective way attentional orienting to the most frequent intervals. Therefore it is possible to postulate the existence of a facilitating effect of anodal tDCS in the modulation of DLPFC, which generated an impact in attentional orienting, lowering RTs to the valid condition (spatial) when compared to sham tDCS.
A atenção pode ser compreendida como um conjunto de mecanismos neurais que facilitam o processamento de informações, pensamentos ou ações relevantes enquanto ignoram outros irrelevantes ou dispersos. Deste modo a atenção permite que o organismo interaja de maneira adequada com o ambiente. Dentre as estruturas cerebrais associados ao controle da atenção, o Córtex Prefrontal Dorsolateral (CPFDL) tem tomado papel de destaque na literatura atual como uma região associada ao controle comportamental. A Estimulação Transcraniana por Corrente Contínua (ETCC) se baseia na aplicação de corrente elétrica de baixa intensidade por meio de eletrodos posicionados no escalpe com o objetivo de modular a atividade de diferentes regiões cerebrais e tem sido utilizada como modo de estudo da função cerebral. Esse trabalho tem como objetivo verificar como a atenção pode ser modulada a partir da aplicação ETCC bilateral sobre o CPFDL, utilizando medidas de tempo de reação (TR) em tarefas de orientação temporal e espacial. Para Tanto foram planejados e executados dois experimentos. No primeiro experimento, relativo à orientação voluntária da atenção espacial, cada participante deveria orientar a atenção para a posição do espaço indicada por uma seta. O segundo experimento, relativo à orientação voluntária da atenção temporal, cada participante deveria orientar a atenção para o intervalo temporal de maior recorrência. Em ambos os casos os participantes deveriam responder o mais rapidamente possível ao aparecimento do alvo pressionado uma tecla de joystick registrando-se assim o seu TR. Participaram desse estudo 18 alunos de graduação (12 no primeiro desenho experimental, e para o segundo desenho experimental foram adicionados mais 6 colaboradores) na faixa etária de 19 à 25 anos. A cada sessão os colaboradores deveriam responder a ambos os experimento enquanto eram submetidos a diferentes polaridades de ETCC (anódica, catódica e placebo) sobre o CPFDL. Foram feitas análises de variância para comparar os fatores estudados. No experimento de orientação espacial a condição anódica produziu TR menores em comparação à condição placebo. No caso do experimento de orientação temporal foi observado que na modulação anódica houve um aumento nos TR no intervalo menos recorrente de 500 ms, indicando que a ETCC anódica pode ter influenciado de modo mais efetivo o direcionamento atencional aos intervalos mais freqüentes. Neste sentido é possível sugerir a existência de um efeito facilitatório da ETCC anódica na moducalçao do CPFDL, o que gerou um impacto no direcionamento atencional, diminuindo os TR para a condição valida (orientação espacial) quando comparados a ETCC placebo.
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Marques, Filho Paulo Ricardo. "Impacto da estimulação transcraniana por corrente contínua (ETCC) na resposta comportamental e neuroquímica de ratos submetidos a um modelo de dor neuropática." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2014. http://hdl.handle.net/10183/110202.
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A Associação Internacional para Estudos da Dor (IASP) define a dor neuropática como a dor que surge diretamente de uma lesão ou doença que afeta o sistema somatossensorial. Os sintomas mais característicos são a hiperalgesia e a alodinia. Além disso, alterações comportamentais como transtornos de ansiedade são comorbidades comuns associadas à dor crônica com características neuropáticas. Os métodos de neuromodulação transcraniana como a ETCC tem se mostrado promissores no tratamento da dor e de alguns transtornos neuropsiquiátricos, uma vez que parecem promover alterações neuroplásticas em nível central. Sendo assim, neste estudo avaliamos o efeito da ETCC na atividade locomotora e exploratória, no comportamento do tipo ansioso e na plasticidade medular e cortical em ratos submetidos a um modelo de dor neuropática. Foram utilizados 144 ratos machos Wistar com 55-65 dias de idade, divididos em 6 grupos: Sham Cirurgia (Sc), Sham Cirurgia+Sham ETCC (SsSE), Sham Cirurgia+ETCC (ScE), Dor Neuropática (Dn), Dor Neuropática+Sham ETCC (DnSE) e Dor Neuropática+ETCC (DnE). O modelo de dor neuropática foi realizado a partir da compressão parcial do nervo isquiático e no 14º dia após a cirurgia iniciou-se o tratamento. A ETCC foi aplicada durante 8 dias com sessões de 20 minutos e foi utilizada uma corrente de 0,5 mA de intensidade. O aparato de Campo Aberto e o Labirinto de Cruz Elevado foram avaliados em dois momentos 24h (Fase I) e sete dias (Fase II) após o tratamento. Os níveis de BDNF foram quantificados em dois momentos 48h (Fase I) e sete dias (Fase II) após a última sessão de tratamento. Nossos resultados demonstram que a dor neuropática induz a uma menor atividade locomotora e exploratória associado a um aumento do comportamento do tipo ansioso em ratos. Por outro lado, o tratamento com ETCC provoca aumento na locomoção e na atividade exploratoria associados à diminuição do comportamento do tipo ansioso. A ETCC mostrou ser capaz de induzir mudanças neuroplásticas alterando níveis de BDNF periférico e central. Concluindo, a ETCC foi capaz de alterar parâmetros comportamentais e neuroplásticos. Podendo ser uma técnica promissora para o tratamento de comorbidades associadas à dor neuropática.The IASP defines neuropathic pain as pain that arises directly from an injury or disease affecting the somatosensory system. The most characteristic symptoms are hyperalgesia and allodynia. Furthermore, behavior changes such as anxiety disorders are common comorbidities associated with chronic pain with characteristics neuropathic. Methods for Neuromodulation transcranial as tDCS are promising in the treatment of pain and some neuropsychiatric disorders, since they seem to further neuroplastic changes in the central level. In this study we evaluate the effect of tDCS on locomotor and exploratory activities, anxiety-like behavior and medullary and cortical plasticity in rats submitted to a neuropathic pain model. A total of 144 male Wistar rats (55-65 days-old; weighing 200–250 g) were divided into 6 groups: Sham Surgery (Ss), Sham Surgery+Sham tDCS (SsS), Sham Surgery+tDCS (SsT), Neuropathic Pain (Np), Neuropathic Pain+Sham tDCS (NpS) and Neuropathic Pain+tDCS (NpT). The model of neuropathic pain was performed by partial sciatic nerve compression and on the 14th day after surgery began tDCS treatment. The tDCS was applied for 8 days with 20-minute sessions and a current intensity of 0.5 mA was used. Open Field and the Plus Maze tests were evaluated at two times 24 (Phase I) and seven days (Phase II) after end of treatment. BDNF levels were quantified in two at 48h (Phase I) and seven days (Phase II) after the last treatment session. Our results demonstrate that neuropathic pain induced a decreased in the locomotor activity and exploratory activity associated with an increase in anxiety-like behavior in rats. On the other hand, treatment with tDCS causes an increase in locomotion and exploratory activity associated with a reduction in anxiety-like behavior. The tDCS proved able to induce neuroplastic changes in BDNF levels by altering the peripheral and central. In conclusion, tDCS changes behavior and neuroplastic parameters; thus it can be a promising technique for the treatment of comorbid conditions associated with neuropathic pain.
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Cachoeira, Carolina Tosetto. "Efeitos da estimulação elétrica transcraniana em adultos com transtorno de déficit de atenção/hiperatividade." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/148126.
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O transtorno do déficit de atenção e hiperatividade (TDAH) é um transtorno do neurodesenvolvimento e sua prevalência na vida adulta é em torno de 2,5%. O tratamento farmacológico, apesar de efetivo, possui importantes limitações, justificando a busca por outras estratégias terapêuticas. A estimulação elétrica transcraniana (EETC) é uma técnica não invasiva de neuroestimulação que tem apresentado resultados promissores em melhorar o desempenho cognitivo em vários distúrbios neuropsiquiátricos, no entanto, poucos estudos avaliaram a sua eficácia e tolerabilidade no TDAH. Foi realizado um ensaio clínico randomizado, duplo-cego e controlado, com estimulação falsa para avaliar a eficácia da EETC nos sintomas de TDAH. Dezessete adultos com TDAH foram randomizados em dois grupos, nove receberam EETC verdadeira e oito, falsa. No grupo da EETC verdadeira foi aplicada estimulação com intensidade de corrente de 2 mA, durante 20 minutos, em cinco dias consecutivos. O ânodo foi posicionado sobre o córtex pré-frontal dorsolateral (CPFDL) direito e o cátodo sobre o CPFDL esquerdo. O grupo controle recebeu estimulação falsa durante o mesmo período. Os sintomas do TDAH foram mensurados por meio da escala Adult ADHD Self-Report Scale (ASRS) e a incapacidade com a escala Sheehan Disability Scale (SDS). As duas escalas foram aplicadas nos seguintes momentos: antes de iniciar (t0) as estimulações, ao final do protocolo (t1) e uma (t2), duas (t3) e quatro semanas (t4) após a intervenção. Observamos redução, estatisticamente significativa, na pontuação das escalas ASRS desatenção (p = 0,02) e SDS (p = 0,04) entre t0 e t1 após a intervenção em comparação ao grupo controle. Na ASRS total também observamos essa tendência, mas não se mostrou estatisticamente significativa (p = 0,07). Ampliando a análise dos dados observamos interação positiva entre tempo e tratamento na pontuação da ASRS total (p = 0,003), ASRS desatenção (p = 0,0001) e SDS (p = 0,001). Os dados deste estudo apontam que a EETC é eficaz para melhorar a atenção em adultos com TDAH. Contudo, mais pesquisas são necessárias para avaliar a eficácia clínica da ETCC nessa população.Attention Deficit Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder with 2,5% prevalence in adulthood. Pharmacological treatment, although effective, has important limitations, justifying the search for other therapeutic strategies. Transcranial direct-current stimulation (tDCS) is a non-invasive neurostimulation technique which has show promising results to improve cognitive performance in several neuropsychiatric disorders, nonetheless few studies have evaluated their efficacy and tolerability in ADHD. A randomized, double-blind, sham-controlled trial was conducted to examine the efficacy of tDCS on ADHD symptoms. in adults with ADHD. Seventeen adults with ADHD were randomized into two groups, nine received active EETC eight, false. In the active group was applied EETC with 2mA current intensity, for 20 minutes, in five consecutive days. Anode was positioned on the right dorsolateral prefrontal cortex (DLPFC) and cathode over the left DLPFC. Control group received false stimulation during the same period. ADHD symptoms were measured using the scale Adult ADHD Self-Report Scale (ASRS) and the disability with Sheehan Disability Scale Scale (SDS). Both scales were applied at the following times: before starting the stimulation, the end of the protocol, and one, two and four weeks after the intervention. Subjects in the active group achieved significant reduction in ASRS inattention (p = 0,02) and SDS (p = 0,04) scores after intervention compared to control group. At ASRS total score was also observed this trend, without statistical significance (p = 0.07). Extending data analysis shows there are positive interaction between time and treatment on ASRS total score (p = 0,003), ASRS inattention (p = 0,0001) and SDS (p = 0,001). These data indicate that tDCS is effective to improving attention in adults with ADHD. However, further research is needed to assess the clinical efficacy of tDCS in this population.
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Brietzke, Aline Patrícia. "Eficácia da estimulação transcraniana com corrente contínua de longo prazo em nível domiciliar sobre o córtex pré-frontal dorsolateral esquerdo na fibromialgia : um ensaio clínico randomizado." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2018. http://hdl.handle.net/10183/179794.
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Introdução: Estimulação transcraniana com corrente contínua (ETCC) é um método não invasivo de estimulação cerebral que modifica o potencial de repouso da membrana neuronal através de uma corrente elétrica de baixa intensidade. Trata-se de uma técnica neuromodulatória aplicável ao contexto terapêutico de disfunções do sistema nervoso implicados na fisiopatologia da dor e transtornos neuropsiquiátricos, com baixo custo, mínimos efeitos adversos e fácil aplicação. A ETCC tem se mostrado eficaz no tratamento de dores crônicas incluindo a fibromialgia (FM) em curto prazo. Seu uso se sustenta na melhor compreensão dos mecanismos fisiopatológicos dessa síndrome, os quais incluem processos de desinibição em nível cortical e infracortical, demonstrado por medidas neurofisiológicas como facilitação e desinibição, assim como redução da potência dos sistemas modulatórios descendentes da dor, além de alterações nas vias nociceptivas periféricas, como as fibras nervosas finas. No entanto, essa alteração isolada não foi previamente associada à disfunção no sistema de modulação descendente da dor (SMDD), observado na FM. As áreas de aplicação da ETCC dependem do objetivo terapêutico. O córtex motor primário (M1) é o alvo mais estudado e com maior contingente de evidências para o tratamento da dor e reabilitação motora, enquanto o córtex pré-frontal dorsolateral esquerdo (DLPFC) tem sido eficaz na depressão e melhora dos componentes psicoafetivos dos pacientes com dor crônica. Seu principal limitador prático é a necessidade de ir ao centro de atendimento durante dias consecutivos, pois o efeito terapêutico sustentado da ETCC necessita repetição das sessões Objetivos: Esta tese está constituída por dois estudos. O primeiro objetiva examinar se a disfunção de fibras finas que ocorre em pacientes com FM está ligada a um mau funcionamento do sistema modulador descendente da dor. No segundo, o objetivo é avaliar a eficácia do uso em longo prazo da ETCC em nível domiciliar na FM, com o objetivo de facilitar o uso e permitir a disponibilização desta técnica a pacientes do Sistema Único de Saúde. Estudo I: No primeiro estudo avaliamos se a disfunção de fibras nervosas finas periféricas está ligada a um mau funcionamento do sistema modulador descendente da dor (SMD) na FM. Métodos: Foi realizado um estudo exploratório no qual 41 mulheres com FM e 28 voluntárias saudáveis foram submetidas a testes psicofísicos que avaliaram a função de fibras sensitivas envolvidas na nocicepção. O teste quantitativo sensorial (QST) foi utilizado para medir o limiar perceptivo térmico (HTT), o limiar de dor térmica (HPT) e o limiar de tolerância à dor térmica (HPTo), bem como avaliar a mudança na Escala Numérica de Dor (NPS0-10) durante uma tarefa de modulação da dor condicionada (CPM-task). A algometria foi utilizada para determinar o limiar de pressão de dor (PPT). Escalas para avaliação de catastrofização, ansiedade, depressão e distúrbios do sono também foram aplicadas. O fator neurotrófico derivado do cérebro (BDNF) foi medido como um marcador de neuroplasticidade. Realizamos modelos de regressão linear multivariada por grupo (saudáveis e FM) para estudar a relação entre a função do SMD e sua relação com as medidas psicofísicas. Resultados: As amostras diferiram em seu perfil psicológico, e nas medidas psicofísicas, o grupo e pacientes com FM apresentou menor sensibilidade e limiares de dor. Na FM, mas não nos saudáveis, os modelos de regressão revelaram que o HTT estava relacionado ao BDNF e ao CPM-Task (Hotelling's Trace = 1,80, P<0,001, poder=0,94, R2=0,64). HTT foi correlacionado positivamente com a CPM-task (B = 0,98, P= 0,004, Partial-ƞ2=0,25), e ao HPT (B=1,61, P=0,008, parcial -ƞ2= 0,21). No entanto PPT não foi correlacionado com o HTT. Na FM a relação do BDNF com CPM-Task teve uma relação negativa (B=-0,04, P=0,043, parcial-ƞ2=0,12) e a HPT foi diretamente proporcional (B= - 0,08, P=0,03, parcial-ƞ2 = 0,14). O BDNF não influenciou no modelo. E os efeitos adversos relatados foram maiores no grupo ativo (17,8%) em comparação com o grupo sham (6,6%). Conclusão: A disfunção sensorial periférica está associada positivamente à disfunção do sistema modulatório descendente da dor e aos níveis séricos de BDNF na FM, o que não ocorre em indivíduos saudáveis. Estudo II: O segundo estudo teve como objetivo avaliar a eficácia do uso domiciliar de 60 sessões da ETCC-ativa e ETCC-simulada aplicadas sobre a área DLPFC esquerda, nas pacientes com diagnóstico de FM. Métodos: Foi realizado um ensaio clínico randomizado, duplo cego, em paralelo, controlado com ETCC-simulada em 20 mulheres com diagnóstico de fibromialgia. A estimulação foi realizada durante cinco dias consecutivos na semana, durante 30 min, com a intensidade de 2 mA, por 12 semanas, totalizando 60 sessões. As pacientes receberam treinamento para uso do equipamento especialmente desenvolvido para uso domiciliar e mantinham contato com o pesquisador responsável por meio de mensagem de texto diariamente. Os efeitos foram medidos por meio da escala visual de dor (EAV) durante o curso de 12 semanas de tratamento, bem como o uso de analgésicos e possíveis eventos adversos, diariamente. Foram avaliados os níveis de depressão, catastrofismo e capacidade funcional para tarefas diárias, QST para verificar limiar de dor e tolerância ao calor, PPT e dosagem dos níveis séricos de BDNF no início, após 30 sessões e no final do tratamento. Um modelo linear misto com efeitos fixos foi usado para comparar mudanças nos escores de dor na EAV ao longo do tratamento. Resultados: A ETCC ativa domiciliar reduziu os escores de dor pela EAV (p<0.001) quando comparado ao sham, com uma redução média de dor de 64% (p<0.001). Além disso, ETCC ativa reduziu significativamente a incapacidade relacionada a dor [B-PCP:S escore total (p=0.023);-ƞ2=0.61]. Também reduziu os escores nas medidas clínicas de depressão, catastrofismo e qualidade do sono [BDI-II, PCS e PSQI (p<0.05)]. No entanto, ETCC ativa aumentou os escores na algometria (PPT) e tolerância térmica (HPTo) (p<0.01). O BDNF não influenciou no modelo. Os efeitos adversos relatados foram maiores no grupo ativo (17,8%) em comparação com o grupo sham (6,6%). Conclusão: A ETCC para uso domiciliar mostrou-se segura e eficaz na redução da dor, incapacidade relacionada a dor, sintomas depressivos e catastróficos e redução do uso de analgésicos. O conjunto de dados desta tese sugere que em pacientes fibromiálgicas, o nível de disfunção do sistema modulador descendente da dor está relacionado ao nível de disfunção de fibras nervosas finas periféricas envolvidas na nocicepção. Além disso, a ETCC de longo prazo em fibromiálgicas foi eficaz na melhora dos sintomas disfuncionais relacionados à dor crônica e se mostrou adequada para uso domiciliar.Introduction: Transcranial direct current stimulation (tDCS) is a noninvasive method of brain stimulation that modifies the resting potential of the neuronal membrane through a low intensity electrical current. It is a neuromodulatory technique to the therapeutic context of dysfunctions of the nervous system implicit in physiotherapy and neuropsychological disorders, with low cost, adverse effects and easy application. tDCS has been effective without a chronic fight process, including fibromyalgia (FM), in which the processes of disinhibition are cortical and infracortical, demonstrated by neurophysiological as intracortical facilitation and desinhibition, as well as reduction of the power of the systems descending pain modulators. In addition, studies have shown a severity of inhibition of central positive correlation with BDNF (Brain Derived Neurotrophic Factor) levels and seems to have some relation to the peripheral nociceptive pathways, as the areas of application of the stimulation depend on the primary motor cortex (M1) is the most studied target and the largest contingent of selection for the treatment of pain and motor reaction, while the dorsolateral prefrontal cortex (DLPFC) was effective in the treatment of depression and psychoaffective components in cases of patients with the chronic condition. Although tDCS has been successful in treating FM, its main limiter is a need for the service center for consecutive days as it has cumulative effect. In fact, the erasure of the sessions guaranteed the therapeutic effect of the ETCC. The application of measures on consecutive days motivated the study of its value when applied at the household level, in order to allow the large-scale treatment technique to be adopted in the Unified Health System. This is proved by two studies. The first objective is to examine whether a fine-fiber dysfunction that occurs in patients with FM is linked to an operation of the pain-modulating system. Neuropathy of long nerve fibers has been implicated by a descriptor of pain, neurophysiological and psychophysiological neurophysiology, as well as skin biopsy studies. However, this comparison was not associated with dysfunction in the descending pain system (DPMS) not on FM. Objective did the study explore the association of dysfunction of small fibers with the DPMS and other substitutes for nociceptive changes in FM. In the second, the term is a measure of long-term use of ETCC at household level in FM Study I: In this first study evaluating the presence of nerve and peripheral fiber failure, it is linked to the functioning of the descending pain modulator system (DPMS) in FM Methods: It was performed an exploratory study with 41 FM women and 28 healthy volunteers whose were evaluated in psychophysical tests that evaluated a function of sensory fibers involved in nociception. The quantitative sensory test (QST) was used to measure the Heat thermal threshold (HTT), the heat pain threshold (HPT) and the thermal pain tolerance (HPTo), as well as the numerical scale of pain (NPS0 -10 ) over a task of modulation of conditioned pain (CPM-task). Algometry was used to determine the pain pressure threshold (PPT). Scales for evaluation of catastrophic, anxiety, depression and sleep disorders were also applied. Brain-derived neurotrophic factor (BDNF) was measured as a marker of neuroplasticity. Multivariate linear regression models by group (health and FM) for a relationship between a descending modulatory system function and its relationship with psychophysical measures. Results: The samples differed in their psychological profile, and in the psychophysical measures, the group and the patients with FM had lower sensitivity and pain thresholds. At FM, regression models revealed that HTT was related to BDNF and CPM-Task (Hotelling's Trace = 1.80, P <0.001, power = 0.94, R2 = 0.64). HTT was positively correlated with a CPM task (B = 0.98, P = 0.004, partial-ƞ2 = 0.25), and HPT (B = 1.61, P = 0.008, partial -ƞ2 = 0.21) . However PPT was not correlated with HTT. In FM, the relationship of BDNF with CPM, a negative relation was found (B = -0.04, P = 0.043, partial- = 2 = 0.12) and HPT was proportionally (B = -0.08, P = 0.03, partial-ƞ2 = 0.14). BDNF did not influence the model. And the adverse effects reported were higher in the active group (17.8%) compared to the sham group (6.6%). Conclusion: Peripheral sensory dysfunction is positively associated with the modulating dysfunction of BDNF levels in FM, which does not occur in isolated individuals. Study II: The second study had the purpose of evaluating the home use of 60 sessions of atDCS and s-tDCS on a left DLPFC area in patients with FM. Methods: A randomized, double-blind, parallel-sham controlled study in 20 women with FM. Stimulation was performed for five consecutive days in the week for 30 min at the intensity of 2 mA for 12 weeks, totaling 60 sessions. Patients were trained to use equipment specially designed for home use and maintained contact with the researcher responsible through daily text message. The effects were measured through visual pain scale (VAS) daily during the course of 12 weeks of treatment, as well as the use of analgesics and possible adverse events daily. The levels of depression, catastrophism and disability for daily tasks were assessed. The QST was used to check pain threshold and tolerance to heat, an algometry was used to check pressure pain threshold (PPT) and blood collection was performed to evaluate serum BDNF levels at baseline, after 30 sessions and at the end of treatment. A Mixed Linear Model with fixed effects was used to compare changes in pain scores in VAS throughout the treatment. Results: Home-based tDCS reduced dairy pain VAS scores (p<0.001), with cumulative mean pain drop of 64% (p<0.001). Furthermore, active home-based tDCS reduced significantly disability due to pain [B-PCP:S total scores (p=0.023; partial-ƞ2=0.61]. And also reduced scores in clinical measures like depression scores, catastrophizing pain scores and sleep quality scores [BDI-II and PCS (p<0.05), PSQI (p<0.05)]. However, active homebased tDCS enhance scores in algometry (PPT) and heat pain tolerance (HPTo) (p<0.01). Conclusion: Home-based anodal tDCS applied over the DLPFC in FM had a baseline neuroplasticity-dependent reduction effect on pain. In addition, it improved the disability due to pain, depressive symptoms and pain catastrophizing. It reduced the analgesic use and increased pressure and heat pain tolerance.
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Laste, Gabriela. "Avaliação pré-clínica da utilização de potenciais terapêuticos no tratamento de dor inflamatória crônica." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2013. http://hdl.handle.net/10183/87161.
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Introdução: Os quadros de dores crônicas são prevalentes, relacionados a alterações físicas e psicológicas, que induzem prejuízos na qualidade de vida. Mais especificamente, a dor inflamatória crônica caracteriza-se por desencadear sustentada hiperexcitabilidade de neurônios no corno dorsal da medula espinhal. O processo nociceptivo da dor crônica inflamatória reduz a atividade do sistema melatonérgico que pode estar associada com dessincronização dos ritmos biológicos. Objetivo: Avaliar o uso pré-clínico de novas opções terapêuticas (melatonina e ETCC) para o tratamento de dor inflamatória crônica. Métodos: A inflamação crônica foi induzida por uma injeção de Adjuvante completo de Freund (ACF). No primeiro experimento, os ratos receberam 60 mg/kg de melatonina ou de veículo (1% de álcool em soro fisiológico), por via intraperitoneal, por três dias consecutivos. No segundo experimento, quinze dias após a injeção os animais foram tratados com injeção intraperitoneal (ip) de dexametasona (0,25 mg/kg) ou seu veículo (solução salina) por 8 dias. No terceiro experimento, os animais foram tratados com dexametasona (0,25 mg/kg) ou seu veículo, melatonina (50 mg/kg) ou seu veículo (8% de etanol em solução salina), e melatonina mais dexametasona ou seus veículos, por 8 dias. No quarto experimento, todos os ratos apresentavam inflamação crônica e foram divididos em dois grupos: estimulação transcraniana por corrente contínua (ETCC) e estimulação sham. Resultados: No primeiro experimento, a administração de melatonina durante 3 dias consecutivos, mostrou um efeito analgésico significativo sobre a dor inflamatória. No segundo experimento, a dexametasona produziu um aumento significativo na latência no teste da placa quente (ANOVA de uma via, P<0,05) e no limiar de retirada no teste de von Frey eletrônico (P <0,005). O grupo dexametasona apresentou aumento dos níveis de BDNF em medula espinhal comparado aos outros grupos (ANOVA de uma via P<0,05). No terceiro experimento, os animais inflamados apresentaram uma desregulação do ritmo de atividade repouso que foi reestabelecido apos o tratamento farmacológico com melatonina que demonstrou ritmo atividade repouso sincronizado. Adicionalmente os animais tratados com dexametasona isolada ou associada a melatonina mostraram inibição acentuada de parâmetros inflamatórios nos achados histológicos, enquanto a melatonina mostrou uma discreta inibição nos mesmos. Ao final do tratamento foi observado um aumento significativo no limiar de retirada da pata no teste de von Frey em grupos tratados (ANOVA de uma via, P<0,05 para todos). No quarto experimento, após oito sessões de 20 minutos de 500 mA de ETCC anódica foi observado efeito antinociceptivo avaliado pelo teste da placa quente imediatamente (P= 0,04) e 24 horas após a última sessão de ETCC (P=0,006). Foi observado também, um aumento de latência de retirada no teste de Von Frey, 24 horas após a última sessão (P= 0,01). Conclusão: Nossos achados confirmam as propriedades antinociceptiva e antiinflamatórias da dexametasona; e podemos sugerir uma relação entre a analgesia e o aumento nos níveis de BDNF em espinhal medula observados apos o tratamento. Por outro lado, a melatonina demonstrou fortes efeitos cronobiótico e antinociceptivo, associados a discreto efeito anti-inflamatório. A associação dexametasona+melatonina não potencializou seus efeitos. Já, a ETCC mostrou-se eficaz induzindo efeito analgésico de longa duração no modelo em estudo. Sendo assim, as propostas de novas terapêuticas abordadas nesta tese parecem ser interessantes opções como adjuvante no tratamento da dor crônica.Background: Chronic pain is related to physical and psychological changes that induce losses in quality of life. More specifically, chronic pain is characterized by trigger sustained hyperexcitability of neurons in the dorsal horn of the spinal cord. The nociceptive process of chronic inflammatory pain reduces the activity of melatonergic system that can be associated with desynchronization of biological rhythms. Objective: Evaluate the pre-clinical use of new therapeutic options (melatonin and tDCS) for the treatment of chronic inflammatory pain. Methods: Chronic inflammation was induced by injection of complete Freund's adjuvant (CFA). In the first experiment, rats received 60 mg/kg of melatonin or vehicle (1% ethanol in saline) intraperitoneally for three consecutive days.In the second experiment, fifteendays after the injection the animals were treated with intraperitoneal (ip) injection of dexamethasone (0.25 mg/kg) or its vehicle (saline) for 8 days. In the third experiment, animals were treated with dexamethasone (0.25 mg/kg) or its vehicle, melatonin (50 mg/kg) or its vehicle (8% ethanol in saline), and melatonin plus dexamethasone or its vehicle for 8 days. In the fourth experiment, all rats had chronic inflammation and were divided into two groups: transcranial direct current stimulation (tDCS) and sham stimulation. Results: In the first experiment, administration of melatonin for 3 consecutive days showed a significant analgesic effect on inflammatory pain. In the second experiment, dexamethasone produced a significant increase in latency in hot plate test (one-way ANOVA, P<0.05) and in withdrawal threshold in the electronic von Frey test (P<0.005). The dexamethasone group had increased levels of BDNF in the spinal cord when compared to the other groups (one-way ANOVA P<0.05). In the third experiment, the inflamed animals showed a dysregulation of the rest-activity rhythm that was restored after pharmacological treatment with melatonin. Additionally, the animals treated with dexamethasone alone or associated with melatonin showed marked inhibition of inflammatory parameters in histological findings, while melatonin showed a slight inhibition in them. At the end of treatment there was a significant increase in paw withdrawal threshold to von Frey test in treated groups (one-way ANOVA, P<0.05 for all). In the fourth experiment, after eight 20-minute sessions of 500 mA of anodal tDCS, it was observed an antinociceptive effect assessed by the hot plate test immediately (P = 0.04) and 24 hours after the last session of tDCS (P = 0.006). It was also observed an increase in withdrawal latency in the von Frey test, 24 hours after the last session (P= 0.01). Conclusion: Our findings confirm the antinociceptive and anti-inflammatory properties of dexamethasone, and we can suggest a relationship between analgesia and increased levels of BDNF in spinal cord observed after treatment. Furthermore, melatonin has demonstrated strong chronobiotic and antinociceptive effects associated with mild anti- inflammatory effect. Dexametasone plus melatonin didn’t potentiate its effects. The tDCS was an effective analgesic inducing long-lasting effect. Therefore, proposals for new therapies discussed in this thesis seem to be interesting choices as an adjunct in the treatment of chronic pain.
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Aze, Oscar. "Performance de marche de patients hémiplégiques après AVC : Déterminants, Réentrainement et Neuromodulation." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSES038.
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Les AVC constituent une urgence hospitalière. Il faut agir au plus tôt pour sauver la vie du malade, limiter les atteintes neurologiques et réduire les dysfonctionnements ultérieurs. Les survivants d’AVC ont des limitations fonctionnelles et en récupèrent incomplètement dans la grande majorité des cas. La plupart d’entre eux marchent avec des séquelles persistantes, à cause de l’hémiparésie. Les résultats modestes obtenus après la rééducation/réadaptation renforcent le besoin de s’interroger sur la part des déterminants de la marche dans la faible capacité de déambulation des hémiparétiques. La problématique de cette thèse est fondée sur la capacité de marche post-AVC. Son but était de rechercher d’une part, les liens possibles entre les atteintes périphériques du muscle, sa neurophysiologie et les limitations de performances motrices observées chez l’hémiparétique ; et d’autre part, les possibilités d’amélioration des processus de commandes centrales de la marche en rapport avec la plasticité cérébrale grâce à l’utilisation d’une technique innovante, la stimulation transcrânienne à courant directe (tDCS) et par un ré-entrainement.Les résultats obtenus à l’issue des quatre études menées apportent de meilleures connaissances sur l’état fonctionnelle du muscle après l’AVC et sur la possibilité d’améliorer la marche de l’hémiparétique. Un état des lieux de la capacité de marche en prenant pour repère l’environnement socio-économique de la prise comme un des déterminants de l’amélioration de la récupération motrice a permis non seulement de comprendre l’importance de cette donnée (souvent négligée par la littérature), dans la capacité de déambulation et donc d’intégration des hémiparétiques. Les autres études ont ressorti, la part des limitations induites par les modifications musculaires après l’AVC et ont favorisé la conception et la mise en place des stratégies de prise en charge de la marche. L’ensemble des altérations structurelle, biochimique et neurophysiologique du muscle suite à l’AVC participe à l’expression des diverses déficiences motrices observées chez le patient hémiplégique, par un amoindrissement de sa force, sa puissance et son endurance. Dans le cas de la réadaptation de la marche chez l’hémiparétique, deux études ont été conduites en utilisant la tDCS. Elles ont permis de montrer que la tDCS peut améliorer la plasticité cérébrale, observation faite à travers le gain global sur les performances de marche avec une stimulation unique ; mais aussi qu’elle peut être utilisée en stimulation itératives combiné à un programme au ré-entrainement à l’effort.La tDCS à cause de sa portabilité, son utilisation relativement facile et surtout son coût moins élevé reste un outil qui peut facilement s’intégrer au contexte de la prise en charge dans les pays à revenus limités. Les résultats obtenus à travers cette Thèse sont porteurs d’espoir quant à l’amélioration de la performance de marche chez l’hémiplégique vasculaireStroke is a hospital emergency. Action must be taken as soon as possible to save the patient's life, limit neurological damage and reduce subsequent dysfunctions. Stroke survivors have functional limitations. Most of them walk with persistent sequelae because of the persistence of hemiparesis. The objective of this thesis was to improve the qualitative and quantitative walking ability of hemiplegic patients of vascular origin by direct current transcranial stimulation and exercise re-training. The results of the four studies provide a better understanding of the functional status of the muscle after stroke and the potential for improving hemiparetic function. The hemiparetic muscle has a performance limitation, because 12 months after ictus, there is: a loss of muscle mass (from 20 to 25%), a gain in fat mass (from 17 to 30.6%), a decrease in the size and proportion of muscle fibers (43% type I fiber) and capillary density (38%), a reduction in the ability to recruit muscle fibers with an increase in the activation time of the motor units and the persistence of rest motor activity. All these structural, biochemical and neurophysiological alterations contribute to the expression of the various motor deficiencies observed in the hemiplegic patient. The other results are related to post-stroke walking. The qualitative and quantitative improvement of walking depends on the quality of care and the socio-economic means used for rehabilitation care. With a single anodic tDCS, gains of 15% during stimulation (p = 0.360) and 25% one hour after stimulation (p = 0.038) were obtained. By combining an anodic tDCS with a 6-week exercise re-training, gains of 5% and 5.7% (p > 0.05) were reported in endurance (6MWT) and speed (10mWT) respectively.It is therefore possible to combine tDCS with the exercise re-training program with good tolerance. The results obtained give hope for improving walking performance in vascular hemiplegic patients
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Stramaccia, Davide Francesco. "An investigation into memory control: neuromodulatory approaches and potential clinical target populations." Doctoral thesis, Università degli studi di Padova, 2016. http://hdl.handle.net/11577/3424912.
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The present doctoral dissertation is composed of six studies investigating
various aspects of cognitive control, with a focus on selective memory retrieval: The brain areas that support this ability, the possibility of modulating its behavioural manifestations with transcranial Direct Current Stimulation (tDCS), its relationship with motor stopping, and its integrity in two clinical populations. Results provided by these experiments highlight four major achievements of this line of research: Firstly, we provided causal evidence for the involvement of right PFC in supporting the cognitive processes underlying memory control, because interfering with the activity of this region was sufficient to disrupt the RIF effect. Secondly, we demonstrated the effectiveness and viability of tDCS as a tool to modulate this peculiar effect. Thirdly, we provided compelling evidence for the advantages of analysing RPP data with a statistical approach that is more consistent with the nature of the data, as well as informative in respect of the different dimensions of the data that contribute to the results. Last, but not least, we contributed to the characterization of the cognitive profile of patients affected by substance-related and addictive disorders and EDs, paving the way to future research that could further investigate the extents and specificity of the previously unexplored memory control deficits that we unveiled in these patients.La presente tesi di Dottorato si compone di sei studi che hanno indagato vari aspetti del controllo cognitivo, con un´attenzione specifica al suo ruolo nell´ambito del recupero mnestico selettivo. Tali studi hanno fornito importanti risultati in merito alle aree cerebrali che supportano questa specifica istanza di controllo cognitivo, alla possibilita´ di manipolarne le manifestazioni comportamentali tramite l’impiego di stimolazione transcranica a corrente continua, alla sua relazione con l´abilita´ di interrompere atti motori, nonche´ alla sua integrita´ in due diverse popolazioni cliniche. In particolare, il presente lavoro ha permesso di stabilire un nesso causale tra la corteccia prefrontale dorsolaterale destra e la capacita´ di esercitare con successo il controllo cognitivo verso memorie interferenti durante il recupero mnestico selettivo. Sono stati inoltre individuati deficit in questa abilita´ in popolazioni cliniche caratterizzate rispettivamente da dipendenza da sostanze come alcol e oppioidi e da disturbi del comportamento alimentare quali l´anoressia nervosa, in cui l´aspetto del controllo cognitivo nel dominio mnestico non era mai stato indagato nella letteratura scientifica.
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Chesters, Jennifer. "Enhancing speech fluency using transcranial direct current stimulation." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:79459ff6-975f-4bd9-8679-1290b20da8b8.
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Producing speech is a highly complex task, involving the integration of sensory and linguistic information, with the precise, high-speed, co-ordination of muscles controlling breathing and the movement of the vocal folds and articulators. In spite of this complexity, producing fluent speech - moving smoothly from one speech sound to the next - can appear effortless. Speech fluency is highly socially valued, and the personal and societal costs of living with a disorder of fluency, such as developmental stuttering, are considerable. The outcomes of behavioural therapies to increase fluency are limited, however, especially for those seeking treatment in adulthood. The overarching aim of this thesis was to investigate how anodal transcranial direct current stimulation (A-TDCS) can be used to increase speech fluency, with a particular focus on the potential application to developmental stuttering. A-TDCS is a noninvasive brain stimulation technique that can enhance the effects of motor, speech, and language training. First, in a series of single-session experiments in typically fluent speakers, I demonstrated that applying A-TDCS over the left IFC increased speech motor learning relative to a sham control, but did not improve consolidation of this learning (chapter 2). Furthermore, I found that neither increasing stimulation intensity from 1 mA to 2 mA, nor changing from a unihemispheric to a bihemispheric configuration, had an additional effect on learning. Next, in single-session study with adults who stutter, I assessed the feasibility of using A-TDCS to improve fluency (chapter 3). Fluency was temporarily induced, by speaking in unison with another person, but the concurrent application of 1-mA unihemispheric A-TDCS over left inferior frontal cortex did not significantly prolong this fluency. Nevertheless, a trend towards stuttering reduction gave some indication that fluency might be increased using a multiple-session approach. Furthermore, I gained a number of important insights from these single-session studies, which I used to inform the design of the final multiple-session trial. In this final study, I completed a randomised controlled trial in 30 adult males with moderate to severe stuttering. Participants were randomized to receive either 1-mA A-TDCS or sham stimulation over left inferior frontal cortex combined with temporary fluency inducing behavioural techniques, for 20 minutes a day over 5 days (chapter 4). A-TDCS significantly reduced disfluency for at least 5 weeks following this intervention. The effect was specific to the speech impairment of development stuttering, as measures of the psycho-social consequences of stuttering were not modulated by A-TDCS. The findings of these studies offer significant promise for the future application of non-invasive stimulation as an adjunctive therapy for adults who stutter. In the concluding chapter, I discuss the important implications of my findings for the future use of this technique.
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Bridges, Nathaniel Reese. "Predicting Vigilance Performance Under Transcranial Direct Current Stimulation." Wright State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=wright1309616451.
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Picinini, Rita dos Santos de Carvalho. "Estudo preliminar sobre o impacto da estimulação transcraniana por corrente contínua em tarefa de multiplicação." Universidade Presbiteriana Mackenzie, 2009. http://tede.mackenzie.br/jspui/handle/tede/1725.
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Previous issue date: 2009-01-27Fundo Mackenzie de Pesquisa
Different mathematical skills have been investigated over time and, with the advance of neuroimaging techniques, such as PET (Positron Emission Tomography) and fMRI (functional Magnetic Resonance), central components of arithmetical processing have been identified in the parietal and the pre-frontal cortices. Besides the advances of the neuroimaging techniques, other techniques such as non-invasive brain modulation have also been studied such as the transcranial magnetic stimulation (TMS) and the transcranial direct current stimulation (TDCS) in the involvement of cognitive functions in the area of calculation. This study aimed at investigating the impact of anodal TDCS applied over the left dorsolateral pre-frontal cortex (LDLPFC), right parietal cortex (RPC), left parietal cortex (LPC) while the subject was performing multiplication operations. Fifteen healthy volunteers, students of psychology, aged between 18 and 30 years old, have held subtests of the WAIS III and the multiplication task. The results showed that the anodal TDCS over the RPC improved the performance of men regarding the number of rightness. The influence of TDCS on volunteers who had worse performance took place not on complex tasks, but simple arithmetical ones. Besides, the influence of TDCS on volunteers who had better performance was in complex tasks, not simple ones. These results show that the effects of the TDCS on a certain function depend on the baseline values of each volunteer. The other stimulation conditions over the LDLPFC and LPC did not show any significant results. The TDCS can bring a beneficial effect in calculation tasks, depending on the intensity, polarity, time and location of stimulation, resulting in the increased or diminished cortex excitability.
Diferentes habilidades matemáticas vêm sendo investigadas ao longo dos tempos e, com o avanço das técnicas de neuroimagem, como PET (Tomografia por emissão de Pósitrons) e fMRI (ressonância magnética funcional) componentes centrais no processamento aritmético vêm sendo identificados em córtex parietal e pré-frontal. Além do avanço das técnicas de neuroimagem, outras técnicas como de modulação cerebral não-invasiva também vêm sendo estudadas, como Estimulação Magnética Transcraniana (EMT) e a Estimulação Transcraniana por Corrente Contínua (ETCC) no envolvimento das funções cognitivas com a área de cálculo. Este estudo teve como objetivo investigar o impacto da ETCC anódica quando aplicada no Córtex Pré-Frontal Dorsolateral (CPFDLE), Córtex Parietal Direito (CPD), Córtex Parietal Esquerdo (CPE) no desempenho em operações de multiplicação. Quinze voluntários saudáveis, estudantes de psicologia, com faixa etária entre 18 e 30 anos, realizaram subtestes do WAIS III e a tarefa de multiplicação. Os resultados desse estudo mostraram que a ETCC anódica aplicada no CPD melhorou o desempenho dos homens em relação ao número de acertos. A influência da ETCC em participantes com pior desempenho em Aritmética se deu em tarefa simples de multiplicação, mas não complexa, ao passo que a influência da ETCC em participantes com melhor desempenho em Aritmética se deu em tarefa complexa de multiplicação, mas não em simples. Tais resultados sinalizam que os efeitos da estimulação em uma determinada função dependem dos valores de linha de base de cada participante As outras condições de estimulações, CPFDLE e CPE não resultaram em efeitos significativos. A ETCC pode produzir um efeito benéfico em tarefas de cálculo, dependendo da intensidade, polaridade, tempo e localização da estimulação, podendo resultar em aumento ou diminuição na excitabilidade do córtex.