Search results for "Cerebellum"
showing 10 items of 202 documents
Topodiagnostic implications of hemiataxia: An MRI-based brainstem mapping analysis
2007
The topodiagnostic implications of hemiataxia following lesions of the human brainstem are only incompletely understood. We performed a voxel-based statistical analysis of lesions documented on standardised MRI in 49 prospectively recruited patients with acute hemiataxia due to isolated unilateral brainstem infarction. For statistical analysis individual MRI lesions were normalised and imported in a three-dimensional voxel-based anatomical model of the human brainstem. Statistical analysis revealed hemiataxia to be associated with lesions of three distinct brainstem areas. The strongest correlation referred to ipsilateral rostral and dorsolateral medullary infarcts affecting the inferior ce…
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…
Monosymptomatic presentation of type I Arnold-Chiari malformation: report of two cases.
1994
Two cases of type I ACM are described, one of which presented with dizziness in late childhood (case 1), the other with mild intention tremor in adulthood (case 2). Cerebellar ectopia should be considered in monosymptomatic patients even in the absence of other symptoms and signs of C.N.S. dysfunction. Magnetic resonance imaging of the craniocervical junction should be performed because it may be diagnostic for type I ACM.
Effect of focal cerebellar lesions on procedural learning in the serial reaction time task
1998
Prior studies have shown that procedural learning is severely impaired in patients with diffuse cerebellar damage (cortical degeneration) as measured by the serial reaction time task (SRTT). We hypothesize that focal cerebellar lesions can also have lateralized effects on procedural learning. Our objective was to assess the effects of focal cerebellar lesions in procedural learning as measured by the SRTT. We studied 14 patients with single, unilateral vascular lesions in the territory of the posterior-inferior or superior cerebellar artery, who were compared with ten age- and sex-matched controls in a one-handed version of the SRTT. Patients with lesions at any other level of the brain or …
Altered effective connectivity during working memory performance in schizophrenia: a study with fMRI and structural equation modeling
2003
The present study aimed to explore altered effective connectivity in schizophrenic patients while performing a 2-back working memory task. Twelve right-handed, schizophrenic patients treated with typical or atypical antipsychotics and 6 healthy control subjects were studied with fMRI while performing a "2-back" working memory task. Effective connectivity within a cortical-subcortical-cerebellar network for mnemonic information processing was assessed and compared between both groups. The path model included cortico-cortical connections comprising the parietal association cortex, ventrolateral prefrontal cortex (VLPFC), and the dorsolateral prefrontal cortex (DLPFC) as well as a cortico-cere…
Changes in Cerebello-motor Connectivity during Procedural Learning by Actual Execution and Observation
2011
Abstract The cerebellum is involved in motor learning of new procedures both during actual execution of a motor task and during observational training. These processes are thought to depend on the activity of a neural network that involves the lateral cerebellum and primary motor cortex (M1). In this study, we used a twin-coil TMS technique to investigate whether execution and observation of a visuomotor procedural learning task is related to modulation of cerebello-motor connectivity. We observed that, at rest, a magnetic conditioning pulse applied over the lateral cerebellum reduced the motor-evoked potentials obtained by stimulating the contralateral M1, indicating activation of a cerebe…
Increased functional connectivity in gambling disorder correlates with behavioural and emotional dysregulation: Evidence of a role for the cerebellum
2020
Gambling disorder (GD) is a psychiatric disease that has been recently classified as a behavioural addiction. So far, a very few studies have investigated the alteration of functional connectivity in GD patients, thus the concrete interplay between relevant function-dependent circuitries in such disease has not been comprehensively assessed. The aim of this research was to investigate resting-state functional connectivity in GD patients, searching for a correlation with GD symptoms severity. GD patients were assessed for gambling behaviour, impulsivity, cognitive distortions, anxiety and depression, in comparison with healthy controls (HC). Afterwards, they were assessed for resting-state f…
Central motor conduction time by magnetic stimulation of the cortex and peripheral nerve conduction follow-up studies in Friedreich's ataxia.
1998
A follow-up clinical study, peripheral motor and sensory nerve conduction velocities and central motor conduction by magnetic stimulation of the cortex were performed in 13 patients with classical Friedreich's ataxia (FA) phenotype, for a period of 9-12 years. Clinical worsening was unrelated to peripheral nerve abnormalities. The amplitude of the nerve action potentials and delayed conduction velocity remained unchanged for several years. Central motor conduction times were abnormal in all patients. Clinical conditions worsened significantly between successive examinations with significant increments in threshold and significant decrement of the amplitude of motor evoked potentials. The re…
Hypo-excitability of cortical areas in patients affected by Friedreich ataxia: A TMS study
2005
The aim of the study was to explore excitability of a motor and a non-motor (visual) area in patients affected by Friedreich ataxia and to correlate neurophysiological data with clinical parameters. Seven patients (3M/4F) and ten healthy controls (5M/5F) participated in the study. The hot-spot for activation of right abductor pollicis brevis was checked by means of a figure-of-eight coil and the motor threshold (MT) on this point was recorded. The phosphene threshold (PT) was measured by means of a focal coil over the occipital cortex as the lower intensity of magnetic stimulation able to induce the perception of phosphenes. The patients showed a significantly higher mean PT (p<.03) and MT …
Cerebellar Contribution to Mental Rotation: a cTBS Study
2013
A cerebellar role in spatial information processing has been advanced even in the absence of physical manipulation, as occurring in mental rotation. The present study was aimed at investigating the specific involvement of left and right cerebellar hemispheres in two tasks of mental rotation. We used continuous theta burst stimulation to downregulate cerebellar hemisphere excitability in healthy adult subjects performing two mental rotation tasks: an Embodied Mental Rotation (EMR) task, entailing an egocentric strategy, and an Abstract Mental Rotation (AMR) task entailing an allocentric strategy. Following downregulation of left cerebellar hemisphere, reaction times were slower in comparison…