Search results for "Motor Cortex"

Brain Oscillatory and Hemodynamic Activity in a Bimanual Coordination Task Following Transcranial Alternating Current Stimulation (tACS): A Combined …

2018

Motor control is associated with synchronized oscillatory activity at alpha (8–12 Hz) and beta (12–30 Hz) frequencies in a cerebello-thalamo-cortical network. Previous studies demonstrated that transcranial alternating current stimulation (tACS) is capable of entraining ongoing oscillatory activity while also modulating motor control. However, the modulatory effects of tACS on both motor control and its underlying electro- and neurophysiological mechanisms remain ambiguous. Thus, the purpose of this study was to contribute to gathering neurophysiological knowledge regarding tACS effects by investigating the after-effects of 10 Hz tACS and 20 Hz tACS at parietal brain areas on bimanual coord…

Cerebellar magnetic stimulation decreases levodopa-induced dyskinesias in Parkinson disease

2009

BACKGROUND: The neural mechanisms and the circuitry involved in levodopa-induced dyskinesia (LID) are still partially obscure. LID can be considered the consequence of an abnormal pattern or code of activity that originates and is conveyed from the basal ganglia to the thalamus and the cortical motor areas. However, not only striatothalamocortical motor circuits but also other interconnected pathways could be implicated in its pathogenesis. METHODS: In a series of experiments, we applied repetitive transcranial magnetic stimulation (rTMS) over the lateral cerebellum in a group of patients with advanced Parkinson disease, to investigate whether modulation of cerebellothalamocortical circuits…

2021

Dystonia, a debilitating neurological movement disorder, is characterized by involuntary muscle contractions and develops from a complex pathophysiology. Graph theoretical analysis approaches have been employed to investigate functional network changes in patients with different forms of dystonia. In this study, we aimed to characterize the abnormal brain connectivity underlying writer's cramp, a focal hand dystonia. To this end, we examined functional magnetic resonance scans of 20 writer's cramp patients (11 females/nine males) and 26 healthy controls (10 females/16 males) performing a sequential finger tapping task with their non-dominant (and for patients non-dystonic) hand. Functional …

Beta Rebound as an Index of Temporal Integration of Somatosensory and Motor Signals

2020

Modulation of cortical beta rhythm (15-30 Hz) is present during preparation for and execution of voluntary movements as well as during somatosensory stimulation. A rebound in beta synchronization is observed after the end of voluntary movements as well as after somatosensory stimulation and is believed to describe the return to baseline of sensorimotor networks. However, the contribution of efferent and afferent signals to the beta rebound remains poorly understood. Here, we applied electrical median nerve stimulation (MNS) to the right side followed by transcranial magnetic stimulation (TMS) on the left primary motor cortex after either 15 or 25 ms. Because the afferent volley reaches the …

Progression of adverse effects over consecutive sessions of transcranial direct current stimulation

2017

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“Accent issue”: foreign accent syndrome following ischemic stroke

2019

Background: Foreign accent syndrome (FAS) is arare syndrome associated with altered speech rhythm and prosody, which listeners perceive as foreign; cerebrovascular accidents, tumors and multiple sclerosis are reported as possible causes of FAS. The pathophysiology of FAS is not yet understood. Case presentation: A 68-year-old Italian man was admitted to the EmergencyDepartment for non-fluent aphasia and dysarthria. Computed tomography (CT) scan did not show abnormalities; the patient was treated with systemic thrombolysis. A repeated brain CT and magnetic resonance imaging (MRI) confirmed an infarct in the left primary motor cortex and mild extension to cortico-subcortical frontal regions. …

P26-S Left and right motor cortical excitability and relationship to motor functions in healthy adolescents

2019

Background The interhemispheric difference in cortical excitability and its relationship to motor functions is unclear. Aim We examined the relationship between handedness, left and right motor cortex excitability and fine and gross motor functions in adolescence. Methods 28 healthy adolescents (age 16–19 years, 19 girls) were studied. Handedness was determined by the Waterloo Handedness Questionnaire. Motor threshold (MT) of the abductor pollicis brevis was measured on both hemispheres using biphasic stimulation, and on the left hemisphere also with monophasic stimulation. Box and block test (BBT) was used for manual dexterity, line run and standing long jump for gross motor tasks. Spearma…

Anodal tDCS of the swallowing motor cortex for treatment of dysphagia in multiple sclerosis: a pilot open-label study

2017

Swallowing difficulties are a common symptom of multiple sclerosis (MS). The early detection and treatment of dysphagia is critical to prevent complications, including poor nutrition, dehydration, and lung infections. Recently, transcranial direct current stimulation (tDCS) has been proven to be effective in ameliorating swallowing problems in stroke patients. In this pilot study, we aimed to assess safety and efficacy of transcranial direct current stimulation (tDCS) in the treatment of dysphagia in MS patients. We screened 30 patients by using the 10-item DYsphagia in MUltiple Sclerosis (DYMUS) questionnaire, and patients at risk for dysphagia underwent a clinical and fiberoptic endoscopi…

Functional electrical therapy for hemiparesis alleviates disability and enhances neuroplasticity

2011

Impaired motor and sensory function is common in the upper limb in humans after cerebrovascular stroke and it often remains as a permanent disability. Functional electrical stimulation therapy is known to enhance the motor function of the paretic hand; however, the mechanism of this enhancement is not known. We studied whether neural plasticity has a role in this therapy-induced enhancement of the hand motor function in 20 hemiparetic subjects with chronic stroke (age 53 ± 6 years; 7 females and 13 males; 10 with cerebral infarction and 10 with cerebral haemorrhage; and time since incident 2.4 ± 2.0 years). These subjects were randomized to functional electrical therapy or conventional phys…

Co-registering kinematics and evoked related potentials during visually guided reach-to-grasp movements.

2013

Background:In non-human primates grasp-related sensorimotor transformations are accomplished in a circuit involving the anterior intraparietal sulcus (area AIP) and both the ventral and the dorsal sectors of the premotor cortex (vPMC and dPMC, respectively). Although a human homologue of such a circuit has been identified, the time course of activation of these cortical areas and how such activity relates to specific kinematic events has yet to be investigated.Methodology/Principal Findings:We combined kinematic and event-related potential techniques to explicitly test how activity within human grasping-related brain areas is modulated in time. Subjects were requested to reach towards and g…