Search results for "Cerebellar cortex"
showing 10 items of 28 documents
The Impacts of Tumor and Tumor Associated Epilepsy on Subcortical Brain Structures and Long Distance Connectivity in Patients With Low Grade Glioma
2018
Low grade gliomas in cerebral cortex often cause symptoms related to higher cerebral functions such as attention, memory and executive function before treatment is initiated. Interestingly, focal tumors residing in one cortical region can lead to a diverse range of symptoms, indicating that the impact of a tumor is extended to multiple brain regions. We hypothesize that the presence of focal glioma in the cerebral cortex leads to alterations of distant subcortical areas and essential white matter tracts. In this study, we analyzed diffusion tensor imaging scans in glioma patients to study the effect of glioma on subcortical gray matter nuclei and long-distance connectivity. We found that th…
Structure, chromosomal localization, and brain expression of human Cx36 gene
1999
Rat connexin-36 (Cx36) is the first gap junction protein shown to be expressed predominantly in neuronal cells of the mammalian central nervous system. As a prerequisite for studies devoted to the investigation of the possible role of this connexin in human neurological diseases, we report the cloning and sequencing of the human Cx36 gene, its chromosomal localization, and its pattern of expression in the human brain analyzed by radioactive in situ hybridization. The determination of the human gene sequence revealed that the coding sequence of Cx36 is highly conserved (98% identity at the protein level with the mouse and rat Cx36 and 80% with the ortholog perch and skate Cx35), and that the…
Hemispheric cerebellar rTMS to treat drug-resistant epilepsy: case reports.
2005
Electrical stimulation of the cerebellar cortex by implanted electrodes has been shown to ameliorate refractory epilepsy. We investigated the potential therapeutic role of high-frequency cerebellar rTMS in patients affected by refractory epilepsy due to single or multiple foci. Six patients, three with single and three with multiple epileptic foci, underwent 20 rTMS sessions. Each session was given daily, excluding weekends, and consisted of two trains of 50 stimuli (5 Hz frequency and 90% motor threshold intensity), separated by 50s interval. rTMS was delivered through a focal coil (2 cm below and lateral to the inion) bilaterally in patients with multiple foci (two trains for hemisphere: …
Changes in cerebellar activation pattern during two successive sequences of saccades
2002
The changes in the cerebellar activation pattern of two successive fMRI scanning runs were determined for visually guided to‐and‐fro saccades in 12 healthy volunteers familiar with the study paradigm. Group and single subject‐analyses revealed a constant activation of the paramedian cerebellar vermis (uvula, tonsils, tuber, folium/declive), which reflects constant ocular motor activity in both runs. A significant decrease in activation of the cerebellar hemispheres found in the second run is best explained by either a decrease in attention or the effects of motor optimization and learning. The significant, systematic changes of the cerebellar activation pattern in two successive runs were n…
Alzheimer's disease: amyloid plaques in the cerebellum
1989
Two specific silver-staining methods demonstrating either extracellular amyloid and/or precursors of amyloid or intraneuronal neurofibrillary changes were used to examine cerebellar pathology in cases of presenile and senile dementia of the Alzheimer type, cases of Down's syndrome, and non-demented controls. The sensitivity of the techniques permitted visualization of large numbers of amyloid deposits in the cerebellar cortex of demented individuals. Similarly large numbers of amyloid deposits were not found in the cerebella of non-demented individuals. Neurofibrillary changes were absent. The majority of amyloid plaques occurred in the molecular layer. Quite a number of these displayed lar…
Increased facilitation of the primary motor cortex following 1 Hz repetitive transcranial magnetic stimulation of the contralateral cerebellum in nor…
2005
Connections between the cerebellum and the contralateral motor cortex are dense and important, but their physiological significance is difficult to measure in humans. We have studied a group of 10 healthy subjects to test whether a modulation of the excitability of the left cerebellum can affect the excitability of the contralateral motor cortex. We used repetitive transcranial magnetic stimulation (rTMS) at 1 Hz frequency to transiently depress the excitability of the left cerebellar cortex and paired-pulse TMS testing of intracortical inhibition (ICI) and intracortical facilitation (ICF) to probe the excitability of cortico-cortical connections in the right motor cortex. The cortical sile…
Modulatory effects of 1 Hz rTMS over the cerebellum on motor cortex excitability
2005
Clinical observations and data from animal experiments point to a physiological facilitatory influence of the deep cerebellar structures on the motor system through the cerebello-thalamo-cortical pathways. The aim of the present study was to explore the long-term effects of low-frequency (1 Hz) repetitive transcranial magnetic stimulation (rTMS) over the cerebellum on short intracortical inhibition (SICI) and facilitation (ICF) of the motor cortex in normal subjects. Eight healthy subjects (mean age 26.9 +/- 3.1) underwent 1 Hz frequency rTMS delivered on the right cerebellar hemisphere. Before and after cerebellar rTMS, SICI and ICF were assessed in the motor cortex contralateral to the st…
Cerebellar parcellation in schizophrenia and bipolar disorder
2019
International audience; Objective: The cerebellum is involved in cognitive processing and emotion control. Cerebellar alterations could explain symptoms of schizophrenia spectrum disorder (SZ) and bipolar disorder (BD). In addition, literature suggests that lithium might influence cerebellar anatomy. Our aim was to study cerebellar anatomy in SZ and BD, and investigate the effect of lithium.Methods: Participants from 7 centers worldwide underwent a 3T MRI. We included 182 patients with SZ, 144 patients with BD, and 322 controls. We automatically segmented the cerebellum using the CERES pipeline. All outputs were visually inspected.Results: Patients with SZ showed a smaller global cerebellar…
The human brain processes visual changes that are not cued by attended auditory stimulation.
2004
Event-related potentials (ERPs) to visual stimuli were recorded from the scalp of eight adult humans performing a task in which they counted vowels from a heard story. In the oddball condition, a repeated (standard) light bar of 50 ms in duration was rarely (P = 0.1) replaced by a (deviant) one differing in orientation from the standard. In the control condition, standards were simply omitted from the series and only (alone-) deviants retained. In both conditions, visual stimuli were asynchronous with auditory-task-relevant stimuli. ERPs to deviants significantly differed in amplitude from those to standards in the midline electrodes centrally, parietally and occipitally at 160-200 ms from …
Amplitude envelope correlation detects coupling among incoherent brain signals.
2000
Event-related potentials (ERPs) to changes in the visual environment were recorded in rabbits. In the oddball condition, infrequently presented (deviant) stimuli occurred in a series of frequently presented (standard) stimuli. In the deviant-alone condition, standards were omitted. ERPs to oddball-deviants differed from those to standards in all recording sites (cerebellar cortex, visual cortex, dentate gyrus). No corresponding differences were found between ERPs to deviants in the oddball condition and those in the deviant-alone condition. However, because ERPs to deviants in the deviant-alone condition and those to standards did not differ either, ERPs to stimulus changes in the oddball c…