Academic literature on the topic 'Gyrus du cingulum'

Introduction. The limbic system primarily responsible for our emotional life and memories is known to undergo degradation with aging and diffusion tensor imaging (DTI) is capable of revealing the white matter integrity. The aim of this study is to investigate age-related changes of quantitative diffusivity parameters and fiber characteristics on limbic system in healthy volunteers.Methods. 31 healthy subjects aged 25–70 years were examined at 1,5 TMR. Quantitative fiber tracking was performed of fornix, cingulum, and the parahippocampal gyrus. The fractional anisotropy (FA) and apparent diffusion coefficient (ADC) measurements of bilateral hippocampus, amygdala, fornix, cingulum, and parahippocampal gyrus were obtained as related components.Results. The FA values of left hippocampus, bilateral parahippocampal gyrus, and fornix showed negative correlations with aging. The ADC values of right amygdala and left cingulum interestingly showed negative relation and the left hippocampus represented positive relation with age. The cingulum showed no correlation. The significant relative changes per decade of age were found in the cingulum and parahippocampal gyrus FA measurements.Conclusion. Our approach shows that aging affects hippocampus, parahippocampus, and fornix significantly but not cingulum. These findings reveal age-related changes of limbic system in normal population that may contribute to future DTI studies.

IntroductionIrony is a form of speech used to convey feelings in an indirect way. Schizophrenic patients usually demonstrate impaired irony processing, associated with poor theory of mind.AimsWe used fMRI to examine neural circuitry underlying deficits in understanding irony in schizophrenia.Methods21 schizophrenic patients and 24 healthy subjects were studied. Short scenarios and three conditions were used: irony condition (IC), irony with linguistic help condition (IHC), and control condition (CC). We used event-related design. Scenarios started with a contextual part, followed by a 2–4s ISI. The ironic sentence appeared next, and a question followed. Between trials an ITI of 5–7s were used.ResultsPatients performed significantly worse in the conditions (IC:p = 0.0003;IHC:p = 0.0034;CC:p = 0.0036). In the IC: patients activated the left insula, left anterior cingulum, right and left superior frontal gyrus (SFG), right middle frontal gyrus (MFG) during the contextual part, and activated the left inferior frontal gyrus (IFG), left middle temporal gyrus (MTG) and right superior temporal gyrus during the statement. In the IHC: patients activated the left precuneus, left IFG, left SFG, left and right MFG, right cuneus and left MTG during the context, and activated right SFG and left posterior cingulum during the statement.ConclusionsPatients probably have an abnormal contextual processing and a missing activation of the theory of mind network during the interpretation of ironic statements. The given linguistic help proved to be efficient help for many patients in processing the context correctly, and in understanding ironic situations more successfully.

Abstract Lower neighborhood socioeconomic status (nSES) is associated with poorer cognitive function; underlying neural correlates are unknown. Cross-sectional associations of nSES (six census-derived measures of income, education, and occupation) and gray matter volume (GMV) of eight memory-related regions (hippocampus, middle frontal gyrus, amygdala, insula, parahippocampal gyrus, anterior, middle, and posterior cingulum) were examined in 264 community-dwelling older adults (mean age=83, 56.82% female, 39.02% black). In linear mixed effects models adjusted for total brain atrophy and accounting for geographic clustering, higher nSES was associated with greater GMV of the left hippocampus, left posterior cingulum, and bilateral insula, middle frontal, and parahippocampal gyri. nSES remained associated with GMV of the right insula (β= -32.26, p=0.026, 95%CI: -60.66, -3.86) after adjusting for individual level age, gender, race, income, and education. The nSES and cognitive function association may not be due to gray matter volume differences; other behavioral and biological mediators should be explored.

Abstract BACKGROUND Childhood intracranial germ cell tumour (iGCT) survivors are prone to radiotherapy-related neurotoxicity which can lead to neurocognitive dysfunction. Diffusion kurtosis imaging (DKI) is a MRI technique that quantifies microstructural changes in the grey and white matter of the brain. This study aims to investigate the associations between MR-DKI metrics, the cognitive and functional outcomes of childhood iGCT survivors. METHOD 20 childhood iGCT survivors who had received cranial radiotherapy were recruited. DKI parameters were determined for iGCT survivors and 18 control subjects. Neurocognitive assessment using the Hong Kong Wechsler Intelligence Scales for Children (HKWISC)/ Wechsler Adult Intelligence Scale – Revised (WAIS-R) and functional assessment using the Lansky/ Karnofsky performance scales were performed for GCT survivors. RESULTS There were significant negative correlation between the IQ scores and the mean diffusivity (MD) in multiple white matter regions of iGCT survivors including: anterior limb of internal capsule, superior fronto-occipital fasciculus, anterior corona radiata, uncinate fasciculus, cingulum and hippocampus. Mean kurtosis (MK) values of the superior fronto-occipital fasciculus were positively correlated with IQ scores. For grey matter, the MD of the olfactory, insula, caudate, heschl gyrus, parahippocampal gyrus, hippocampus, anterior cingulum, frontal inferior operculum, middle and superior temporal gyrus, middle and superior frontal orbital gyri, cuneus and precentral gyrus were negatively correlated with IQ scores. Most of the microstructural changes with associated functional impairment were white matter regions. CONCLUSION Our study identified vulnerable brain regions with significant white and grey matter microstructural changes that were associated with impaired cognitive function or deficits in physical functioning.

OBJECTIVEGliomas invading the anterior corpus callosum are commonly deemed unresectable due to an unacceptable risk/benefit ratio, including the risk of abulia. In this study, the authors investigated the anatomy of the cingulum and its connectivity within the default mode network (DMN). A technique is described involving awake subcortical mapping with higher attention tasks to preserve the cingulum and reduce the incidence of postoperative abulia for patients with so-called butterfly gliomas.METHODSThe authors reviewed clinical data on all patients undergoing glioma surgery performed by the senior author during a 4-year period at the University of Oklahoma Health Sciences Center. Forty patients were identified who underwent surgery for butterfly gliomas. Each patient was designated as having undergone surgery either with or without the use of awake subcortical mapping and preservation of the cingulum. Data recorded on these patients included the incidence of abulia/akinetic mutism. In the context of the study findings, the authors conducted a detailed anatomical study of the cingulum and its role within the DMN using postmortem fiber tract dissections of 10 cerebral hemispheres and in vivo diffusion tractography of 10 healthy subjects.RESULTSForty patients with butterfly gliomas were treated, 25 (62%) with standard surgical methods and 15 (38%) with awake subcortical mapping and preservation of the cingulum. One patient (1/15, 7%) experienced postoperative abulia following surgery with the cingulum-sparing technique. Greater than 90% resection was achieved in 13/15 (87%) of these patients.CONCLUSIONSThis study presents evidence that anterior butterfly gliomas can be safely removed using a novel, attention-task based, awake brain surgery technique that focuses on preserving the anatomical connectivity of the cingulum and relevant aspects of the cingulate gyrus.

AbstractLimbic white matter pathways link emotion, cognition, and behavior and are potentially malleable to the influences of traumatic events throughout development. However, the impact of interactions between childhood and later life trauma on limbic white matter pathways has yet to be examined. Here, we examined whether childhood maltreatment moderated the effect of combat exposure on diffusion tensor imaging measures within a sample of military veterans (N = 28). We examined five limbic tracts of interest: two components of the cingulum (cingulum, cingulate gyrus, and cingulum hippocampus [CGH]), the uncinate fasciculus, the fornix/stria terminalis, and the anterior limb of the internal capsule. Using effect sizes, clinically meaningful moderator effects were found only within the CGH. Greater combat exposure was associated with decreased CGH fractional anisotropy (overall structural integrity) and increased CGH radial diffusivity (perpendicular water diffusivity) among individuals with more severe childhood maltreatment. Our findings provide preliminary evidence of the moderating effect of childhood maltreatment on the relationship between combat exposure and CGH structural integrity. These differences in CGH structural integrity could have maladaptive implications for emotion and memory, as well as provide a potential mechanism by which childhood maltreatment induces vulnerability to later life trauma exposure.

ObjectivesOne third of patients with drug resistant focal mesial temporal lobe epilepsy (MTLE) fail to achieve long-term seizure freedom following temporal lobe resections. Reasons for failure may include ictal onset outside the temporal lobe (TL), termed ‘pseudotemporal lobe epilepsy’ (pTLE), with propagation from strongly connected neighboring areas or temporal plus (TL+) epilepsy, when the epileptogenic zone primarily involves the temporal lobe and also extends to neighboring regions. In such cases the perisylvian and orbito-frontal (OF) cortices, cingulum and temporo-parieto-occipital junction may be implicated. Stereoelectroencephalography (SEEG) is a procedure in which electrodes are stereotactically placed within predefined brain regions to delineate the SOZ and allows evaluation of deep anatomical structures adjacent to the TL. SEEG electrode contacts sample from a core radius of 3–5 mm. It is unclear which sub-regions of target structures should be preferentially implanted to optimally detect the network involved in seizure onset and rapid propagation. Using normalized average group templates of structural connectivity from patients with hippocampal sclerosis (HS), we determine the greatest connectivity to critical sub-regions and based upon this propose optimal locations for SEEG targeting.DesignObservational cross-sectional study.SubjectsTwelve patients with HS (6 right) that had undergone SEEG and pre-operative diffusion imaging were identified from a prospectively maintained database.MethodsWhole brain connectomes with 10 million tracts were generated using cortical seed regions derived from whole brain GIF parcellations. Normalized group templates were generated separately for right and left HS patients. Orbitofrontal cortex (OF), insula (INS), cingulum (Cing) and temporo-parietal-occipital junction (supramarginal gyrus, angular gyrus, precuneus, fusiform gyrus and lingual gyrus) were segmented into surgically targetable subregions. All subregions had similar volumes. Connectivity of the amygdalohippocampal complex (AHC) was defined based on the number of streamlines terminating in the subregions of interest.ResultsLeft HS showed preferential connections to the ipsilateral: posterior part of lateral OF cortex, posterior short gyrus of anterior INS, posterior part of the posterior Cing, middle part of lingual gyrus, posterior part of precuneus and middle part of fusiform gyrus. Right HS showed preferential connections to the ipsilateral: posterior part of the lateral OF cortex, anterior long gyrus of posterior INS, posterior part of posterior Cing, anterior part of lingual gyrus and posterior part of precuneus.ConclusionsUsing whole brain connectomes we determine surgically feasible targets in sub-regions based on greatest connectivity to the AHC. We propose that SEEG targeting utilizing computer-assisted planning may improve the understanding of the overall network connectivity in order to enhance the diagnostic utility of the SEEG implantation. SEEG electrode placement within structures associated with pTLE and TL +may aid in delineating the SOZ if the correct sub-regions are targeted. This should be evaluated prospectively.

Background and Purpose. Spasticity is a positive sign of upper motor neuron syndrome that usually develops weeks after a stroke. The mechanisms that lead to its appearance are not completely understood, namely, the cortical regions whose lesion may induce spasticity.Summary of Cases. We report two patients with an ischaemic stroke entailing the anterior cingulate gyrus (pericallosal artery territory), who presented with acute hemiplegia and spasticity since symptom onset. Spasticity resolved within days after onset.Conclusions. The acute destruction of the anterior cingulate region, interrupting inhibitory projections towards lower motor centres, probably explains the acute onset of spasticity that occurred in these two patients. Further studies addressing the role of this region in acute and chronic disturbances of muscular tone are necessary.

Background:There is a high comorbidity of posttraumatic stress (PTS) and mild traumatic brain injury (mTBI), with largely overlapping symptomatology, in military service members.Objective:To examine white matter integrity associated with PTS and mTBI as assessed using diffusion tensor imaging (DTI).Method:Seventy-four active-duty U.S. soldiers with PTS (n = 16) and PTS with co-morbid history of mTBI (PTS/mTBI; n = 28) were compared to a military control group (n = 30). Participants received a battery of neurocognitive and clinical symptom measures. The number of abnormal DTI values was determined (>2 SDs from the mean of the control group) for fractional anisotropy (FA) and mean diffusivity (MD), and then compared between groups. In addition, mean DTI values from white matter tracts falling into three categories were compared between groups: (i) projection tracts: superior, middle, and inferior cerebellar peduncles, pontine crossing tract, and corticospinal tract; (ii) association tracts: superior longitudinal fasciculus; and (iii) commissure tracts: cingulum bundle (cingulum-cingulate gyrus and cingulum-hippocampus), and corpus callosum.Results:The comorbid PTS/mTBI group had significantly greater traumatic stress, depression, anxiety, and post-concussive symptoms, and they performed worse on neurocognitive testing than those with PTS alone and controls. The groups differed greatly on several clinical variables, but contrary to what we hypothesized, they did not differ greatly on primary and exploratory analytic approaches of hetero-spatial whole brain DTI analyses.Conclusion:The findings suggest that psychological health conditions rather than pathoanatomical changes may be contributing to symptom presentation in this population.

Objective: Application of diffusion tensor imaging (DTI) to explore the changes of FA value in patients with Parkinson's disease (PD) with mild cognitive impairment. Methods: 27 patients with PD were divided into PD with mild cognitive impairment (PD-MCI) group (n = 7) and PD group (n = 20). The original images were processed using voxel-based analysis (VBA) and tract-based spatial statistics (TBSS). Results: The average age of pd-mci group was longer than that of PD group, and the course of disease was longer than that of PD group. Compared with PD group, the voxel based analysis-fractional anisotropy (VBA-FA) values of PD-MCI group decreased in the following areas: bilateral frontal lobe, bilateral temporal lobe, bilateral parietal lobe, bilateral subthalamic nucleus, corpus callosum, and gyrus cingula. Tract-based spatial statistics-fractional anisotropy (TBSS-FA) values in PD-MCI group decreased in bilateral corticospinal tract, anterior cingulum, posterior cingulum, fornix tract, bilateral superior thalamic radiation, corpus callosum(genu, body and splenium), bilateral uncinate fasciculus, bilateral inferior longitudinal fasciculus, bilateral superior longitudinal fasciculus, bilateral superior fronto-occipital fasciculus, bilateral inferior fronto-occipital fasciculus, and bilateral parietal-occipital tracts. The mean age of onset in the PD-MCI group was greater than that in the PD group, and the disease course was longer than that in the PD group. Conclusion: DTI-based VBA and TBSS post-processing methods can detect abnormalities in multiple brain areas and white matter fiber tracts in PD-MCI patients. Impairment of multiple cerebral cortex and white matter fiber pathways may be an important causes of cognitive dysfunction in PD-MCI.

Outre le stress chronique, la douleur chronique représente une cause majeure de dépression. En effet, environ 50% des patients qui souffrent d’une douleur chronique développent des troubles de l’humeur. Les perturbations des structures cérébrales impliquées dans la perception de la douleur pourraient contribuer à cette comorbidité, dont les mécanismes restent pourtant mal compris. Nous avons étudié l’implication du cortex cingulaire antérieur (CCA) dans les conséquences sensorielles et émotionnelles de la douleur neuropathique dans un modèle murin. Nous avons montré qu’une lésion du CCA ou une inhibition des neurones pyramidaux du CCA préviennent l’émergence des désordres émotionnels dans notre modèle. De plus, nos résultats indiquent que ces conséquences émotionnelles coïncident avec une hyperactivité neuronale dans le CCA. En conclusion, nous montrons que le CCA est une structure clé pour la dépression induite par la douleur neuropathique
Besides chronic stress, chronic pain is one of the prevalent determinants for depression. Indeed, around 50% of chronic pain patients develop mood disorders. Alterations in brain regions implicated in pain processing may also be involved in affective processing, thus potentially be responsible of mood disorders. However, the underlying mechanisms of this comorbidity are not yet elucidated. Here, we studied the role of the anterior cingulate cortex (ACC) in the somatosensory, aversive and anxiodepressive consequences of neuropathic pain. We showed that a permanent lesion or temporal inhibition of ACC pyramidal neurons blocked the development or suppressed the expression of an anxiodepressive phenotype in neuropathic mice. In addition, anxiodepressive-like behavior coincided with ACC hyperactivity. In conclusion we show that the ACC is a critical hub for neuropathic pain-induced depression

La Maladie de Parkinson (MP) est une maladie neuro-dégénérative fréquente, caractérisée par une déplétion dopaminergique striatale. Elle s'accompagne précocement de troubles cognitifs, notamment attentionnels, dont l’origine reste imprécise. Deux hypothèses sont évoquées : un déficit du contrôle volontaire de l'attention vers la tâche en cours (processus de type « top-down » (TD)) ou un défaut d’inhibition des informations non pertinentes pour la tâche (par défaillance de processus de type « bottom-up » (BU)). Les processus attentionnels, souvent explorés par la mesure de variables comportementales, peuvent également bénéficier de l'enregistrement des composantes N200 et P300 des potentiels évoqués cognitifs (PEC). La P300 comprend deux sous-composantes : (1) la P3a, survenant préférentiellement après un distracteur, reflétant un traitement BU ; (2) la P3b, associée à la détection de cibles et reflétant un traitement TD. La N200 se décompose en une « no-go-N2 » antérieure, impliquée dans la détection de la déviance et les mécanismes d’inhibition et une « go-N2 » postérieure, engagée dans les processus de catégorisation des cibles. Dans la MP, ces composantes ont le plus souvent une latence allongée et une amplitude réduite. La modification des générateurs des PEC dans la MP n’a, à notre connaissance, jamais été explorée. L’objectif de cette thèse est de préciser les mécanismes sous-jacents aux troubles attentionnels dans la MP. En cas de dysfonctionnement TD, les réseaux impliqués dans la genèse de la P3b et/ou de la N200 postérieure pourraient être altérés. Si une dysfonction BU en est à l’origine, les générateurs de la P3a et/ou de la N200 antérieure devraient être modifiés. Nous avons enregistré en haute résolution les PEC de 15 sujets sains jeunes, au cours d’un paradigme « oddball » visuel à trois stimulus afin d’étudier les générateurs des PEC chez le sujet sain. Le même enregistrement a ensuite été effectué chez 15 sujets atteints d’une MP comparés à 15 sujets appariés. Les latences et amplitudes des composantes des PEC ont été comparées au moyen d’analyses de variance. L’exploration des générateurs des PEC a été effectuée pour chaque sujet et dans chaque condition au moyen d’une méthode distribuée d’analyse de source, swLORETA (standardized weighted low resolution tomography). Les analyses statistiques de groupes des générateurs de la P300 ont été effectuées au moyen du logiciel SPM, celles de la N200 au moyen de méthodes de permutations. Chez les sujets jeunes, le réseau fronto-pariétal dorsal (FPD) apparaît impliqué dans la genèse des deux composantes de la P300, le réseau fronto-pariétal ventral étant spécifique du traitement de la cible. L’étude des générateurs de la N200 a mis en évidence le rôle prépondérant du cortex cingulaire antérieur (CCA) en interaction avec les réseaux fronto-pariétaux, le precuneus et le cortex cingulaire postérieur. Dans la MP, il existait une réduction des sources de la P300 générée par le distracteur au niveau du cortex dorsolatéral préfrontal (DLPF) appartenant au réseau FPD, en lien avec une augmentation des fausses alarmes aux distracteurs chez les patients, en faveur d'une défaillance des processus BU dans la MP. Une diminution des sources de la N200 a également été constatée au niveau du cortex DLPF et du CCA, dans toutes les conditions. Ceci suggère un dysfonctionnement de ces deux régions dès le stade précoce des processus attentionnels, seul le fonctionnement du cortex DLPF restant altéré spécifiquement dans le traitement des distracteurs lors des étapes ultérieures de traitement de l’information. Ces anomalies résultent probablement du dérèglement des boucles baso-corticales reliant le striatum associatif au cortex DLPF et CCA. Ceci entrainerait une altération du contrôle cognitif et des processus BU responsable d’anomalies de détection de la déviance et d'inhibition des stimulus non pertinents, sous-jacentes aux troubles de l’attention sélective dans la MP
Parkinson’s disease (PD) is a frequent neurodegenerative disease which is responsible for striatal dopaminergic depletion. PD patients present an early cognitive impairment, particularly attentional disorders. The origin of this impairment is still debated. It could result from a reduced allocation of attentional resources to the ongoing task (“top-down” process (TD)) or a defective inhibition of irrelevant events (failure of “bottom-up” filtering process (BU). Investigation of attentional processes mostly rely on behavioral analysis, but the study of the N200 and P300 components of the cognitive event-related potentials (ERPs) may be of interest. P300 can be divided into two subcomponents: (1) P3a, which occurs preferentially after distracter stimuli and is associated with BU processes; (2) P3b, related to target detection and associated with TD mechanisms. The N200 also comprises two main components: an anterior “no-go-N2", involved in mismatch detection and inhibition mechanisms, and a posterior “go-N2”, related to target categorization processes. Most of previous studies in PD have shown a longer latency and reduced amplitude of N200 and P300. To the best of our knowledge, modulation of their generators in PD has never been investigated. The main aim of this work was to improve our knowledge of the mechanisms of attention disorders in PD. If the attentional impairment in PD results from a failure of TD processes, this would result in modifications of the networks underlying the P3b and/or the posterior N2 during target detection. Alternatively, if this disorder is consecutive to a failure of BU processes, this would lead to difficulty in resisting interference from distracter stimuli and would change the characteristics of the P3a and/or anterior N200. ERPs were recorded in 15 young healthy subjects with high resolution electroencephalography during a three stimuli oddball paradigm in order to localize N200 and P300 generators in healthy subjects. Then, they were recorded with the same procedure in 15 patients with PD and 15 matched healthy controls. Group comparisons of the ERPs latency and amplitude were performed with analyses of variance. Generators of the ERPs components were identified for each subject and in each condition with a distributed source localization method, swLORETA (standardized weighted low resolution tomography). Group analyses of swLORETA solutions were performed with SPM® for the P300 subcomponents and with a permutation method for the N200. In young healthy controls, we showed an involvement of the dorsal frontoparietal (DFP) network in both P3a and P3b generation, while the ventral frontoparietal network was specific to target processing. The anterior cingulate cortex (ACC) that interacts with the frontoparietal networks, had a preponderant role in N200 generation. Other areas, namely the precuneus and the posterior cingulate cortex, which are connected to the ACC, are specific generators of some of the N200 subcomponents. In PD, a reduction of distracter-elicited P300 generators was found in the dorsolateral prefrontal cortex (DLPF), which is part of the DFP network, accordingly with an increased commission rate for distracter stimuli. These results suggest a failure of BU processes in PD. A reduced number of N200 generators was also displayed in both DLPF and ACC whatever the stimulus. This suggests a dysfunction of both the DLPF and the ACC at an early stage of attentional processes in PD, while only distracter processing was later impaired, in relation with a DLPF dysfunction. These abnormalities probably result from disturbances of the basocortical loops that link the associative striatum to the DLPF and ACC. This would then produce a sustainable alteration of cognitive control and BU processes, responsible for abnormal mismatch detection and inhibition of irrelevant stimuli, which would underlie the selective attention impairment in PD

Le cortex cingulaire antérieur (CCA) est une région préfrontale située au centre d’un réseau permettant l’échange d’informations cognitives, motrices, limbiques et viscérales, la plaçant ainsi comme un sujet incontournable dans l’étude de pathologies complexes telles que les troubles anxio-dépressifs. Afin de pouvoir aborder ces pathologies chez la souris, nous avons établi par traçage neuronal le connectome complet des différentes aires composant le CCA. Nous avons ainsi montré qu’une grande majorité des structures de ce connectome communique de manière réciproque avec cette région et que, selon les aires cingulaires, des spécificités de densité d'innervation et de topographie peuvent exister. Ceci suggère des fonctions partagées mais également des rôles plus spécifiques à chaque aire. A partir de ce connectome, nous avons ensuite montré, par une approche optogénétique associée à des tests comportementaux, que l'activation répétée de la projection de l’amygdale au CCA est susceptible d'induire des comportements de type anxio-dépressif chez des souris naïves. Ce travail met donc en évidence le rôle d'une partie du connectome du CCA dans l'établissement des troubles de l'humeur
The anterior cingulate cortex (ACC) is a prefrontal region located at the center of a network allowing the sharing of cognitive, motor, limbic and visceral information, placing it as an interesting target for the study of complex pathologies like mood disorders. To investigate these diseases in mice, we provided the complete connectome of each ACC areas by a tract-tracing approach. We demonstrated that the majority of structures constituting this connectome are reciprocally connected with the ACC and that some density and topographical connection specificities were observed among cingulate areas. These results potentially suggest some shared functions between cingulate areas, also completed by specific roles inherent to each area. Using this connectome, we demonstrated that the repeated activation of the amygdala projection to the ACC was able to induce anxiodepressive-like behaviors in naïve mice, by using optogenetics combined with behavioral tests. This study highlights for the first time the implication of a portion of the ACC connectome in the establishment of mood disorders