Relevant bibliographies by topics / R-fMRI

Contents

  1. Journal articles
  2. Dissertations / Theses
  3. Books
  4. Book chapters
  5. Conference papers

Academic literature on the topic 'R-fMRI'

Author: Grafiati
Published: 4 June 2021
Last updated: 1 February 2022

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Journal articles on the topic "R-fMRI"

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Siegel, Joshua S., Gordon L. Shulman, and Maurizio Corbetta. "Measuring functional connectivity in stroke: Approaches and considerations." Journal of Cerebral Blood Flow & Metabolism 37, no. 8 (May 25, 2017): 2665–78. http://dx.doi.org/10.1177/0271678x17709198.

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Recent research has demonstrated the importance of global changes to the functional organization of brain network following stroke. Resting functional magnetic resonance imaging (R-fMRI) is a non-invasive tool that enables the measurement of functional connectivity (FC) across the entire brain while placing minimal demands on the subject. For these reasons, it is a uniquely appealing tool for studying the distant effects of stroke. However, R-fMRI studies rely on a number of premises that cannot be assumed without careful validation in the context of stroke. Here, we describe strategies to identify and mitigate confounds specific to R-fMRI research in cerebrovascular disease. Five main topics are discussed: (a) achieving adequate co-registration of lesioned brains, (b) identifying and removing hemodynamic lags in resting BOLD, (c) identifying other vascular disruptions that affect the resting BOLD signal, (d) selecting an appropriate control cohort, and (e) acquiring sufficient fMRI data to reliably identify FC changes. For each topic, we provide guidelines for steps to improve the interpretability and reproducibility of FC-stroke research. We include a table of confounds and approaches to identify and mitigate each. Our recommendations extend to any research using R-fMRI to study diseases that might alter cerebrovascular flow and dynamics or brain anatomy.
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Yan, Chao-gan, Qingyang Li, and Lei Gao. "PRN: a preprint service for catalyzing R-fMRI and neuroscience related studies." F1000Research 3 (December 22, 2014): 313. http://dx.doi.org/10.12688/f1000research.5951.1.

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Sharing drafts of scientific manuscripts on preprint hosting services for early exposure and pre-publication feedback is a well-accepted practice in fields such as physics, astronomy, or mathematics. The field of neuroscience, however, has yet to adopt the preprint model. A reason for this reluctance might partly be the lack of central preprint services for the field of neuroscience. To address this issue, we announce the launch of Preprints of the R-fMRI Network (PRN), a community funded preprint hosting service. PRN provides free-submission and free hosting of manuscripts for resting state functional magnetic resonance imaging (R-fMRI) and neuroscience related studies. Submissions will be peer viewed and receive feedback from readers and a panel of invited consultants of the R-fMRI Network. All manuscripts and feedback will be freely available online with citable permanent URL for open-access. The goal of PRN is to supplement the “peer reviewed” journal publication system – by more rapidly communicating the latest research achievements throughout the world. We hope PRN will help the field to embrace the preprint model and thus further accelerate R-fMRI and neuroscience related studies, eventually enhancing human mental health.
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Yan, Chao-gan, Qingyang Li, and Lei Gao. "PRN: a preprint service for catalyzing R-fMRI and neuroscience related studies." F1000Research 3 (August 19, 2015): 313. http://dx.doi.org/10.12688/f1000research.5951.2.

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Sharing drafts of scientific manuscripts on preprint hosting services for early exposure and pre-publication feedback is a well-accepted practice in fields such as physics, astronomy, or mathematics. The field of neuroscience, however, has yet to adopt the preprint model. A reason for this reluctance might partly be the lack of central preprint services for the field of neuroscience. To address this issue, we announce the launch of Preprints of the R-fMRI Network (PRN), a community funded preprint hosting service. PRN provides free-submission and free hosting of manuscripts for resting state functional magnetic resonance imaging (R-fMRI) and neuroscience related studies. Submitted articles are openly discussed and receive feedback from readers and a panel of invited consultants from the R-fMRI Network. All manuscripts and feedback are freely accessible online with citable permanent URL for open-access. The goal of PRN is to supplement the peer reviewed journal publication system – by more rapidly communicating the latest research achievements throughout the world. We hope PRN would help the field to embrace the preprint model and thus further accelerate R-fMRI and neuroscience related studies, eventually enhancing human mental health.
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Mousavi, S., A. Massot Tarrus, F. Bihari, S. Hayman Abello, B. Hayman Abello, and S. Mirsattari. "fMRI for language: how can it replace the Wada test?" Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques 42, S1 (May 2015): S27. http://dx.doi.org/10.1017/cjn.2015.133.

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Background: The goal of our project is to assess the feasibility of replacing the invasive Wada test considered as the gold standard with non-invasive fMRI test for assessment of language dominance preoperatively. Methods: fMRI test with three language paradigm tasks (verb generation, sentence completion and naming) were conducted on our cohort of patients. fMRI laterality indices (LI) were then defined as a ratio (L-R)/(L+R) between the number of activated voxels in the left and right ROIs for Anterior Language Area (ALA) and Posterior Language Area (PLA). fMRI results were divided into the right (LI < -0.2), left (LI > 0.2) or bilateral (-0.2 < LI <0.2) hemispheric language dominance and compared to the results of the Wada test. Results: 28 patients were studied. The concordance rate between Wada and fMRI tests for the ALA and PLA was 68.2% and 52.2% for sentence completion; 56% and 52% for verb generation and 25% and 35% for naming paradigm, respectively. Conclusions: Sentence completion and verb generation fMRI paradigms showed higher concordance with Wada test than naming paradigm. The higher discordance between the Wada test and fMRI was related to bilateral results suggestive of less stringent thresholds used for either test.
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Mousavi, S., A. Massot Tarrus, F. Bihari, S. Hayman Abello, B. Hayman Abello, and S. Mirsattari. "Concordance rate between Wada and fMRI tests for visual memory assessment of patients with medically intractable temporal lobe epilepsy." Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques 42, S1 (May 2015): S10. http://dx.doi.org/10.1017/cjn.2015.74.

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Background: There is not enough evidence to prove either invasive Wada or non-invasive fMRI test predicts postoperative memory changes more accurately in patients with refractory temporal lobe epilepsy (TLE). In this study, concordance between fMRI and Wada test for postoperative assessment of visual memory is investigated. Methods: fMRI test with a novel scene-encoding task were conducted on our cohort of patients. fMRI laterality indices (LI) were then defined as a ratio (L-R)/(L+R) between the number of activated voxels in the left and right of two regions: hippocampus+parahippocampus (Region A) and temporal lobe - (hippocampus+parahippocampus) (Region B). fMRI results were divided into the right (LI < -0.2), left (LI > 0.2) or bilateral (-0.2 < LI <0.2) hemispheric memory dominance and compared to the results of the Wada test. Results: 19 patients were studied (14 left TLE, 3 right TLE and 2 bilateral TLE). The concordance rate between Wada and fMRI tests was 36.8% and 42.1% for regions A and B. Conclusions: Based on the results, the concordance rate between the Wada test and the fMRI test is not high. As a future work, we will investigate the correlation of each test to postoperative memory outcome.
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Yan, Chao-Gan, Xiao Chen, Le Li, Francisco Xavier Castellanos, Tong-Jian Bai, Qi-Jing Bo, Jun Cao, et al. "Reduced default mode network functional connectivity in patients with recurrent major depressive disorder." Proceedings of the National Academy of Sciences 116, no. 18 (April 12, 2019): 9078–83. http://dx.doi.org/10.1073/pnas.1900390116.

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Major depressive disorder (MDD) is common and disabling, but its neuropathophysiology remains unclear. Most studies of functional brain networks in MDD have had limited statistical power and data analysis approaches have varied widely. The REST-meta-MDD Project of resting-state fMRI (R-fMRI) addresses these issues. Twenty-five research groups in China established the REST-meta-MDD Consortium by contributing R-fMRI data from 1,300 patients with MDD and 1,128 normal controls (NCs). Data were preprocessed locally with a standardized protocol before aggregated group analyses. We focused on functional connectivity (FC) within the default mode network (DMN), frequently reported to be increased in MDD. Instead, we found decreased DMN FC when we compared 848 patients with MDD to 794 NCs from 17 sites after data exclusion. We found FC reduction only in recurrent MDD, not in first-episode drug-naïve MDD. Decreased DMN FC was associated with medication usage but not with MDD duration. DMN FC was also positively related to symptom severity but only in recurrent MDD. Exploratory analyses also revealed alterations in FC of visual, sensory-motor, and dorsal attention networks in MDD. We confirmed the key role of DMN in MDD but found reduced rather than increased FC within the DMN. Future studies should test whether decreased DMN FC mediates response to treatment. All R-fMRI indices of data contributed by the REST-meta-MDD consortium are being shared publicly via the R-fMRI Maps Project.
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Stocco, Andrea. "Coordinate-Based Meta-Analysis of fMRI Studies with R." R Journal 6, no. 2 (2014): 5. http://dx.doi.org/10.32614/rj-2014-020.

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Liebel, Spencer W., Uraina S. Clark, Xiaomeng Xu, Hannah H. Riskin-Jones, Brittany E. Hawkshead, Nicolette F. Schwarz, Donald Labbe, Beth A. Jerskey, and Lawrence H. Sweet. "An FMRI-Compatible Symbol Search Task." Journal of the International Neuropsychological Society 21, no. 3 (March 2015): 231–38. http://dx.doi.org/10.1017/s1355617715000144.

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AbstractOur objective was to determine whether a Symbol Search paradigm developed for functional magnetic resonance imaging (FMRI) is a reliable and valid measure of cognitive processing speed (CPS) in healthy older adults. As all older adults are expected to experience cognitive declines due to aging, and CPS is one of the domains most affected by age, establishing a reliable and valid measure of CPS that can be administered inside an MR scanner may prove invaluable in future clinical and research settings. We evaluated the reliability and construct validity of a newly developed FMRI Symbol Search task by comparing participants’ performance in and outside of the scanner and to the widely used and standardized Symbol Search subtest of the Wechsler Adult Intelligence Scale (WAIS). A brief battery of neuropsychological measures was also administered to assess the convergent and discriminant validity of the FMRI Symbol Search task. The FMRI Symbol Search task demonstrated high test–retest reliability when compared to performance on the same task administered out of the scanner (r=.791; p<.001). The criterion validity of the new task was supported, as it exhibited a strong positive correlation with the WAIS Symbol Search (r=.717; p<.001). Predicted convergent and discriminant validity patterns of the FMRI Symbol Search task were also observed. The FMRI Symbol Search task is a reliable and valid measure of CPS in healthy older adults and exhibits expected sensitivity to the effects of age on CPS performance. (JINS, 2015, 22, 1–8)
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Fontoura, Denise Ren da, Daniel de Moraes Branco, Mauricio Anés, Jaderson Costa da Costa, and Mirna Wetters Portuguez. "Language brain dominance in patients with refractory temporal lobe epilepsy: a comparative study between functional magnetic resonance imaging and dichotic listening test." Arquivos de Neuro-Psiquiatria 66, no. 1 (March 2008): 34–39. http://dx.doi.org/10.1590/s0004-282x2008000100009.

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PURPOSE: To identify brain dominance for language functions with DLT and correlate these results with those obtained from fMRI in patients suffering from intractable temporal lobe epilepsy. METHOD: This study reports on 13 patients who underwent pre-surgical epileptic evaluation between April and October 2004 at the Epilepsy Surgery Program, Hospital Sao Lucas, PUCRS. In DLT, dominance was assessed through a consonant-vowel task, whereas in fMRI patients performed a verb generation task. RESULTS: Our results identified a correlation between the fMRI lateralization index and the DLT ear predominance index and reply difference index (r=0.6, p=0.02; Pearson Correlation Coefficient), showing positive correlation between results obtained from fMRI and DLT. CONCLUSION: DLT was found to significantly correlate with fMRI. These findings indicate that DLT (a non-invasive procedure) could be a useful tool to evaluate language brain dominance in pre-surgical epileptic patients as it is cheaper to perform than fMRI.
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Roder, Constantin, Edyta Charyasz-Leks, Martin Breitkopf, Karlheinz Decker, Ulrike Ernemann, Uwe Klose, Marcos Tatagiba, and Sotirios Bisdas. "Resting-state functional MRI in an intraoperative MRI setting: proof of feasibility and correlation to clinical outcome of patients." Journal of Neurosurgery 125, no. 2 (August 2016): 401–9. http://dx.doi.org/10.3171/2015.7.jns15617.

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OBJECTIVE The authors' aim in this paper is to prove the feasibility of resting-state (RS) functional MRI (fMRI) in an intraoperative setting (iRS-fMRI) and to correlate findings with the clinical condition of patients pre- and postoperatively. METHODS Twelve patients underwent intraoperative MRI-guided resection of lesions in or directly adjacent to the central region and/or pyramidal tract. Intraoperative RS (iRS)–fMRI was performed pre- and intraoperatively and was correlated with patients' postoperative clinical condition, as well as with intraoperative monitoring results. Independent component analysis (ICA) was used to postprocess the RS-fMRI data concerning the sensorimotor networks, and the mean z-scores were statistically analyzed. RESULTS iRS-fMRI in anesthetized patients proved to be feasible and analysis revealed no significant differences in preoperative z-scores between the sensorimotor areas ipsi- and contralateral to the tumor. A significant decrease in z-score (p < 0.01) was seen in patients with new neurological deficits postoperatively. The intraoperative z-score in the hemisphere ipsilateral to the tumor had a significant negative correlation with the degree of paresis immediately after the operation (r = −0.67, p < 0.001) and on the day of discharge from the hospital (r = −0.65, p < 0.001). Receiver operating characteristic curve analysis demonstrated moderate prognostic value of the intraoperative z-score (area under the curve 0.84) for the paresis score at patient discharge. CONCLUSIONS The use of iRS-fMRI with ICA-based postprocessing and functional activity mapping is feasible and the results may correlate with clinical parameters, demonstrating a significant negative correlation between the intensity of the iRS-fMRI signal and the postoperative neurological changes.
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Dissertations / Theses on the topic "R-fMRI"

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Hollinger, Avrum. "Design of fMRI-compatible electronic musical interfaces." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=116045.

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The designs of two functional magnetic resonance imaging-compatible electronic interfaces for use in neuropsychological studies involving musical tasks are presented. The devices, a two-button response box in the form of a computer mouse and a piano keyboard, were designed for rhythmic tapping and piano performance tasks, respectively. In order to correlate changes in neural activation acquired through magnetic resonance imaging (MRI) with task performance, the electronic collection of behavioural data, such as the timing of button or key presses was required. These behavioural measures were captured electronically and communicated to a host computer for synchronization with feedback, stimuli, and the MRI scanner itself. As well, data was logged for offline analysis. Due to the intense and volatile electromagnetic fields, most commercially-available electronic interfaces do not function properly and can even pose a serious safety hazard within the MRI scanner environment. Therefore these custom-designed interfaces were free of ferromagnetic parts and all electronic components were relegated to the control room outside of the scanner environment. Acquisition of button and key presses was accomplished using fibre optic sensors, which are immune to electromagnetic interference. The devices performed successfully within the scanner, and MRI scans showed no image artifacts caused by the prototypes. Sensing of key and button transition velocity was sufficient after extensive calibration. Next generation prototypes are planned and will implement more robust and tighter tolerance manufacturing, improved sensing techniques, the acquisition of isometric forces, and an auto-calibration scheme.
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Achtman, Rebecca L. "Investigation of shape processing using psychophysics and fMRI." Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82811.

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In the early stages of visual processing (primary visual cortex) shapes are sampled by discrete, localized, visual filters. The integration of the outputs of these local filters allows us to detect global shape information. Although this integration process is critical for visual processing beyond the primary visual cortex, it remains poorly understood. This thesis investigates what limits the performance of the mechanisms used to detect global structure. In particular, we asked four questions: (1) What information is important for detecting global form? (2) How well can we detect shape defined by changes in contrast? (3) Do the spatial properties of detectors that process global shape change across the visual field? (4) What cortical areas are involved in global shape processing?
We used psychophysical methods and functional magnetic resonance imaging (fMRI) to study the integration of local filters for global shape processing in normal adult observers. All our stimuli were spatially bandpass and contained global circular structure.
Overall, our findings suggest that the visual system combines the outputs of local detectors both across the visual field and over different stimulus attributes (e.g. contrast, spatial frequency, spatial position, polarity, contrast-defined information). Our excellent sensitivity to these globally structured patterns suggests the involvement of higher-order mechanisms optimized for global processing. However, these higher-order mechanisms are not localized in an individual retinotopic area nor is there a systematic hierarchical increase in activity throughout the ventral processing pathway in response to globally structured stimuli. In conclusion, significant processing of shapes occurs at both the local and the global level.
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Liao, Chuanhong 1964. "Estimating the delay of the hemodynamic response in fMRI data." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=31260.

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The technique of functional magnetic resonance imaging (fMRI) is rapidly developing from one of technical interest to wide clinical application. fMRI exploits the fact that brain neural activity produces a change in blood oxygenation level dependent (BOLD) response which is recorded at each point in the brain. In a typical experiment, a subject is given a stimulus or cognitive task, and the statistical question is to relate it to the BOLD response, usually via a linear model. The BOLD response is not instantaneous; it is delayed and smoothed by about 6 seconds. In this thesis we propose a rapid method of estimating and making inference about this delay. Our method is compared to other alternatives, and validated on an fMRI data set from an experiment in pain perception.
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Dumoulin, Serge O. "Motion mechanisms and cortical areas in human vision : psychophysics and fMRI." Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82860.

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Our visual world contains both luminance- (first-order) and contrast-defined (second-order) information. Distinct mechanisms underlying the perception of first-order and second-order motion have been proposed from electrophysiological, psychophysical and neurological studies. In this thesis psychophysical and human brain imaging (fMRI) experiments are described that support the notion of distinct mechanisms, but extend the previous studies by providing evidence for a functional dissociation and a relative cortical specialization for first- and second-order motion.
Using psychophysical methods, a directional anisotropy was found for second-order but not first-order motion in peripheral vision. This anisotropy is interpreted as a functional dissociation implicating the second-order mechanism in optic flow processing.
Identification of early visual cortical areas is a prerequisite to any functional assessment of these visual areas. To this aim a novel human brain mapping method has been developed which automatically segments early human retinotopic visual areas. Unlike previous methods this procedure does not depend on a cortical surface reconstruction and thereby greatly simplifies the analysis.
In a combined psychophysical and fMRI study, distinct cortical regions, in occipital and parietal lobes, were preferentially activated by either first- or second-order motion. These results provide evidence for the idea that first-order motion is computed in V1 and second-order motion in later occipital visual areas. In addition the results suggest a functional dissociation of the two kinds of motion beyond the occipital lobe consistent with a role for the second-order mechanism in optic flow analysis.
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Wieckowska, Marguerite. "Cerebral blood flow measurement using fMRI and pet : a validation study." Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=79271.

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Functional magnetic resonance imaging (fMRI) is a technique allowing the study of hemodynamic changes in the brain. Having a number of advantages over positron emission tomography (PET), the current gold standard, fMRI appears like an attractive alternative to study brain function. However, the measurements obtained with fMRI have not been rigorously validated.
This thesis describes a study comparing cerebral blood flow (CBF) changes measured using a flow-sensitive alternating inversion recovery (FAIR) fMRI perfusion method, to the ones obtained using PET. We scanned 10 healthy normal volunteers under identical experimental conditions during presentation of 4 levels of visual stimulation and one level of hypercapnia. The CBF changes were compared in 4 regions-of-interest.
Good correspondence was found in the locations of the CBF changes. FAIR CBF changes had a higher signal-to-noise ratio and presented a monotonic increase with stimulation intensity, absent in PET measurements. FAIR measurements were correlated to PET but slightly lower. Statistical analysis of the data did not show that FAIR measurements were significantly different from PET ones.
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Crane, David. "Neural correlates of spatial and temporal context memory, an fMRI investigation." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=32582.

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Recent neuroimaging studies have found greater left and right prefrontal cortex (PFC) activity during spatial source and temporal recency tasks, respectively. It is unclear whether these findings result from inherent differences in PFC contributions to spatial vs. temporal memory retrieval or to differences in task difficulty and/or structure. To address this issue, I used event-related functional magnetic resonance imaging to assess healthy adults while they performed spatial and temporal memory tasks for faces, matched for structure and difficulty. Findings show greater left-lateralized activity during both spatial and temporal context retrieval tasks, with a greater degree of recruitment during spatial tasks. A response number manipulation, designed to identify regions related to selection, activated the left-inferior PFC. After controlling for task structure, such that both spatial and temporal retrieval tasks required more categorical versus continuous processing, we only observed left-lateralized PFC activations; rather than previously reported laterality effects in PFC during spatial vs. temporal context retrieval. We interpret these activations as reflecting left PFC involvement in domain-general cognitive control processes that are important for categorically based memory retrieval; such as, response selection and covert verbalization of stimuli.
Des études récentes de neuro-imagerie ont trouvé une plus grande activité du cortex préfrontal (CPF) gauche et droit lors de tâche de mémoire spatiale et de récence temporelle, respectivement. Il n'est pas clair si ces résultats sont dus à une différence inhérente de la contribution du CPF aux tâches de remémoration spatiale et temporelle, ou s'il s'agit de différences dans la difficulté et/ou la structure des tâches. Pour répondre à cette question, j'ai utilisé l'imagerie par résonance magnétique fonctionnelle pour évaluer la performance d'adultes en santé lors de tâches de mémoire spatiale et temporelle pour les visages, en appariant les tâches au niveau de leur structure et de leur difficulté. Les résultats démontrent une plus grande activité latéralisée à gauche durant toutes les tâches, en plus de démontrer un plus grand degré de recrutement lors des tâches spatiales, qui sont de nature catégorique. De plus, une manipulation du nombre de réponse, conçue pour déterminer quelles régions se rapportent à la sélection des réponses et à la mémoire de travail verbal, activa le CPF inférieur gauche. Ces résultats suggèrent une contribution latéralisée à gauche du CPF pour les réseaux favorisant les tâches de mémoire catégorique ainsi que les tâches de traitement exécutif général, plutôt que spécifiquement pour l'information spatiale ou temporelle.
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Mortin, Catherine Leanne. "fMRI responses to first- and second-order modulations of visual textures." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82621.

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The world around us contains a variety of visual information, both first-order (luminance-defined) and second-order (defined by characteristics other than luminance). Previous studies suggest that the human visual cortex employs distinct mechanisms for segregating regions whose borders are defined by modulations of first- and second-order properties. This study uses a new approach of human psychophysics and fMRI experiments to explore the brain responses to both first-order and second-order (orientation, spatial frequency and contrast) texture borders. The results reveal differential activation among these modulations both in known retinotopic areas and in higher occipital/parietal regions. Orientation modulated textures elicit significantly different responses compared to modulations of other properties; whereas spatial frequency and contrast modulated textures produce similar responses. These findings suggest that higher visual cortical areas are heavily involved in texture processing, with a functional dissociation between segregating textures with modulations of (a) orientation, (b) spatial frequency or contrast and (c) luminance.
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Malik, Saima. "Neural substrates of feeding behavior : insights from fMRI studies in humans." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=115850.

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Feeding behavior is a complex phenomenon involving homeostatic signals, and non-homeostatic inputs such as visual cues. In primates, exposure to food-related sensory cues has been shown to elicit cephalic phase responses as well as trigger central appetitive processing, in a motivationally-dependent manner. Neural structures consistently implicated in such responses and/or in the regulation of ingestive behavior in general, in both monkeys and in humans, include the amygdala, insula, striatum, hypothalamus, and frontal and occipital cortices. In humans however, the cerebral response to visual food stimulation remains minimally explored.
Functional Magnetic Resonance Imaging (fMRI) provides information about state-dependent changes in local neuronal activity in vivo. Using fMRI, the present dissertation examined changes in human brain activity to food and nonfood pictures following the pharmacological induction of hunger with the orexigenic hormone ghrelin (Study 1), and following manipulation of the cognitive state of food expectation (Study 2).
Our data reinforce the involvement of a distributed frontal-limbic-paralimbic circuit in the central processing of food imagery, under both experimental conditions. The first study revealed that intravenous ghrelin administration potently modulated food-associated neural responses III areas involved in reward, motivation, memory, and attention (amygdala, insula, orbitofrontal cortex, striatum, hippocampus, midbrain, visual areas). This suggests that metabolic signals such as ghrelin may promote food consumption by enhancing the appetitive response to food cues via engagement of the hedonic network.
The second study revealed that brain regions activated in the 'expectant' state (i.e. when subjects were anticipating food reward) were at least partially dissociable from those in the 'not expectant' state. In particular, recruitment of the dorsolateral prefrontal cortex, a principal component in the cognitive control network, exclusively in the 'not expectant' condition, may signal an attempt to suppress appetite in the absence of food expectation. Areas of convergence were observed in the amygdala and insula.
Obesity is rapidly becoming the major cause of excess mortality worldwide; therefore, understanding how the central nervous system controls appetite and nutrient consumption is of considerable interest. The projects in this thesis offer significant insights regarding the effects two select factors (one intrinsic and the other extrinsic) on the neural reaction to visual food stimuli, in healthy male participants.
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Albanese, Marie-Claire. "FMRI evidence of memory representations of somatosensory stimuli in the human brain." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=102949.

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Distinct brain regions process innocuous vibration and cutaneous heat pain. The role of these areas in the perception of pain is still a matter of debate; and the role of these areas in the mediation of memory of somatosensory stimuli is uncertain and has not been studied with brain imaging in healthy human volunteers. All experiments described here, involved an experimental design, which included a delayed-discrimination paradigm and functional magnetic resonance imaging (fMRI). In manuscript #1, we aimed at unraveling the cerebral correlates of attention and spatial localization of innocuous vibrotactile stimuli applied to the right volar surface of the forearm. In this study, we report that increased degrees of attention to the vibrotactile stimuli were associated with heightened levels of activation in several brain areas. In manuscript #2, we investigated the short-term memory for sensory aspects (intensity and location) of cutaneous heat pain delivered to two areas (thenar and hypothenar eminences) of the palm of the right hand. In this experiment, the memory and control trials were presented in blocks, whereby the subjects could predict what trials were going to follow. This study revealed that the presentation of painful stimuli evoked activation in different brain regions than those activated during the online maintenance (interstimulus interval or ISI) of the intensity and spatial features of those stimuli; a process, which I will refer to short-term memory. In manuscript #3, we investigated again short-term memory for sensory aspects of heat pain (as in manuscript #2), but in this case, the memory and control trials were presented in a randomized order. In this study, we found that the perception and short-term memory of pain were processed by a comparable network of areas. The predictability of the memory and control trials may have contributed to these findings.
La vibration inoffensive ainsi que la chaleur douloureuse cutanée sont traitées pardifférentes régions du cerveau. Le rôle de ces régions dans la perception de la douleurest controversé; et le rôle de ces régions dans la mémoire des stimuli somatosensorielsest incertain et n'a jamais encore été étudié en imagerie cérébrale chez des sujetshumains sains. Le design expérimental de toutes les études décrites ici comprenait unparadigme de 'delayed-discrimination' et l'imagerie par résonance magnétiquefonctionnelle (IRMf). L'étude #1 visait à élucider les corrélats cérébraux de l'attention etde la localisation spatiale des stimuli vibrotactiles inoffensifs présentés à la faceantérieure de l'avant-bras droit. Dans cette étude, nous avons trouvé que des degrésélevés d'attention portée aux stimuli vibrotactiles étaient associés à des niveaux accrusd'activation dans plusieurs zones du cerveau. Dans l'étude #2, nous avons enquêté surla mémoire à court-terme des caractéristiques sensorielles (intensité et emplacement)de la chaleur douloureuse cutanée présentée à deux endroits (éminences thénar ethypothénar) de la paume de la main droite. Dans cette étude, les essais mémoire etcontrôle étaient présentés en bloc, ou de sorte que les participants pouvaient prévoir dequel type serait le prochain essai. Cette étude a révélé que la présentation des stimulidouloureux a évoqué une activation de différentes régions cérébrales que celles quiétaient activées lors de la rétention de l'intensité et de l'emplacement des stimulationsdurant l'intervalle inter-stimuli (liS); un processus que je qualifierai de mémoire à courtterme.Dans l'étude #3, nous avons également enquêté sur la 'mémoire à court-termedes aspects sensoriels de la chaleur douloureuse (tout comme dans l'étude #2), maisdans ce cas, les essais mémoire et contrôle étaient présentés de façon aléatoire. Danscette étude, nous avons trouvé que la perception de la douleur ainsi que la mémoire àcourt-terme de la douleur étaient traitées par un réseau de régions semblable. Laprévisibilité des essais mémoire et contrôle peut avoir contribué à ce résultat.
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Copeland, Laura. "Audiovisual processing of affective and linguistic prosody : an event-related fMRI study." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=111605.

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This study was designed to clarify some of the issues surrounding the nature of hemispheric contributions to the processing of emotional and linguistic prosody, as well as to examine the relative contribution of different sensory modalities in processing prosodic structures. Ten healthy young participants were presented with semantically neutral sentences expressing affective or linguistic prosody solely through the use of non-verbal cues (intonation, facial expressions) while undergoing tMRI. The sentences were presented under auditory, visual, as well as audio-visual conditions. The emotional prosody task required participants to identify the emotion of the utterance (happy or angry) and the linguistic prosody task required participants to identify the type of utterance (question or statement). Core peri-sylvian, frontal and occipital areas were activated bilaterally in all conditions suggesting that processing of affective and linguistic prosodic structures is supported by overlapping networks. The strength of these activations may, in part, be modulated by task and modality of presentation.
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Books on the topic "R-fMRI"

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Konrad, Kerstin, Adriana Di Martino, and Yuta Aoki. Brain volumes and intrinsic brain connectivity in ADHD. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780198739258.003.0006.

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Neuroimaging studies have increased our understanding of the neurobiological underpinnings of ADHD. Structural brain imaging studies demonstrate widespread changes in brain volumes, in particular in frontal-striatal-cerebellar networks. Based on the widespread nature of structural and functional brain abnormalities, approaches able to capture the organizing principles of large-scale neural systems have been used in ADHD. These include diffusion magnetic resonance imaging (MRI) and resting state functional MRI (R-fMRI). Complementary to findings of volumetric studies, diffusion investigations have reported structural connectivity abnormalities in frontal-striatal-cerebellar networks. In parallel, R-fMRI studies point towards abnormalities in the interaction of multiple networks, extending the functional territory of explorations beyond cognitive and motor control. In the future, a deep phenotypic characterization beyond diagnostic categories combined with longitudinal study designs and novel analytical approaches will accelerate the pace towards clinical translations of neuroimaging to improve the detection and prediction of neural trajectories and treatment response in ADHD.
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Book chapters on the topic "R-fMRI"

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Borst, Jelmer P., and John R. Anderson. "Using the ACT-R Cognitive Architecture in Combination With fMRI Data." In An Introduction to Model-Based Cognitive Neuroscience, 339–52. New York, NY: Springer New York, 2015. http://dx.doi.org/10.1007/978-1-4939-2236-9_17.

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Elaiyaraja, K., M. Senthil Kumar, and B. Chidambararajan. "Intelligent Big Data Domain for R-fMRI Big Data Preprocessing—An Optimized Approach." In Intelligence in Big Data Technologies—Beyond the Hype, 433–41. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-5285-4_43.

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Wang, Rifeng, Jie Xiang, Haiyan Zhou, Yulin Qin, and Ning Zhong. "Simulating Human Heuristic Problem Solving: A Study by Combining ACT-R and fMRI Brain Image." In Brain Informatics, 53–62. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-04954-5_16.

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Mair, Patrick. "Analysis of fMRI Data." In Use R!, 409–50. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-93177-7_14.

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Pereira-Sanchez, Victor, and Pilar de Castro-Manglano. "Resting-state functional magnetic resonance imaging (R-FMRI) as a potential tool for early diagnosis and outcome prediction in attention deficit hyperactivity disorder (ADHD)." In Neurological Disorders and Imaging Physics, Volume 4. IOP Publishing, 2020. http://dx.doi.org/10.1088/978-0-7503-1822-8ch5.

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Conference papers on the topic "R-fMRI"

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Seshamani, S., A. Blazejewska, C. Gatenby, S. Mckown, J. Caucutt, M. Dighe, and C. Studholme. "Robust R∗2 map estimation from motion scattered slices for fetal fMRI." In 2015 IEEE 12th International Symposium on Biomedical Imaging (ISBI 2015). IEEE, 2015. http://dx.doi.org/10.1109/isbi.2015.7164003.

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Wang, Nan, and Xiaojing Yang. "Study on Different Strategies to Solve the Problem of Addition and Subtraction: FMRI Combined with ACT-R." In 2021 IEEE 5th Advanced Information Technology, Electronic and Automation Control Conference (IAEAC). IEEE, 2021. http://dx.doi.org/10.1109/iaeac50856.2021.9390696.

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Kulkarni, Prachi H., Kratika Gupta, S. N. Merchant, and Suyash P. Awate. "R-FMRI Reconstruction from K-T Undersampled Simultaneous-Multislice (SMS) MRI with Controlled Aliasing: Towards Higher Spatial Resolution." In 2020 IEEE 17th International Symposium on Biomedical Imaging (ISBI). IEEE, 2020. http://dx.doi.org/10.1109/isbi45749.2020.9098450.

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Kulkarni, Prachi H., S. N. Merchant, and Suyash P. Awate. "Bayesian reconstruction of R-fMRI from K-T undersampled data using a robust, subject-invariant, spatially-regularized dictionary prior." In 2018 IEEE 15th International Symposium on Biomedical Imaging (ISBI 2018). IEEE, 2018. http://dx.doi.org/10.1109/isbi.2018.8363579.

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Aradhya, Abhay M. S., Vigneshwaran Subbaraju, Suresh Sundaram, and Narasimhan Sundararajan. "Regularized Spatial Filtering Method (R-SFM) for detection of Attention Deficit Hyperactivity Disorder (ADHD) from resting-state functional Magnetic Resonance Imaging (rs-fMRI)." In 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC). IEEE, 2018. http://dx.doi.org/10.1109/embc.2018.8513522.

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Петров, V. Petrov, Гаценко, and A. Gatsenko. "Ferrite resonators for mm-wave range devices." In XXIV International Conference. Москва: Infra-m, 2016. http://dx.doi.org/10.12737/23263.

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Currently on the way are R&amp;D works targeted to expand operational frequencies of microwave devices, including frequency selective ones. The expansion occurs both at low and at high end of the frequency range. Due to the microwave communication systems trend of increasing transmitted data flow rate and volume, as well as for precise object resolution by the vision systems, one needs to shift microwave device operational frequencies to the mm-wave range. Operational frequencies of mm-wave range microwave devices are defined by crystallographic magnetic anisotropy field and magnetic activity of the ferrite material (4πМS/ΔH), related with saturation magnetization and ferromagnetic resonance (FMR) line width. For creation of mm-wave range frequency selective devices are needed the ferrite resonators made of materials with high crystallographic magnetic anisotropy field values, as well as high saturation magnetization and narrow FMR line width. R&amp;D works undertaken in the institute show that such materials can be created on the basis of ferrites with hexagonal structure. As a starting point for the development of the material was taken barium hexaferrite with M-type structure (BaFe12O19). Single crystals with composition BaFe12-xAlxO19 and BaFe12-xScxO19 were received from a solution in melt. By this way one may create materials with anisotropy field values from 5 to 50 kÖe, saturation magnetization from 3900 to 4700 Gauss, narrow FMR line width, and Curie temperature from 370° to 445° С. The dependencies of crystallographic magnetic anisotropy field and saturation magnetization vs diamagnetic dilution and temperature are investigated, as well as FMR line width vs temperature, density and orientation of the growing grains.
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