Physiological studies of the corticomotor projection to the hand after subcortical stroke

Byrnes, M. L. and Thickbroom, G W. and Phillips, B. A. and Wilson, S. A. and Mastaglia, F. L. (1999) Physiological studies of the corticomotor projection to the hand after subcortical stroke. Clinical Neurophysiology, 110 (3). pp. 487-498. ISSN 1388-2457


Objective: The mechanisms which lead to recovery of motor function after a stroke are poorly understood. Functional reorganization of cortical motor centres is thought to be one of the factors which may contribute to recovery. We have investigated the extent of reorganization which occurs at the level of the primary motor cortex after a lesion of the corticospinal pathway. Methods: Transcranial magnetic stimulation was used to map the topography of the primary corticomotor projection to the abductor pollicis brevis muscle and study changes in cortical motor thresholds and corticospinal conduction in a group of 20 subjects with subcortical infarcts of varying duration (1 week to 15 years) and varying degrees of motor deficit. Results: There was a broad correlation between motor evoked potential (MEP) amplitude and motor thresholds on the one hand and the severity of motor deficit and site and extent of the lesion on the other. Shifts in the cortical motor maps were found in both early and late cases, irrespective of the site of the lesion, but were more frequent in the longer standing cases. Shifts were usually along the mediolateral axis but anteroposterior shifts were found in some late cases. Conclusion: Our findings indicate that there is functional reorganization of the corticomotor projection in subjects who regain a degree of motor control following a subcortical lesion sparing the motor cortex.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Faculty/School / Institute/Centre: Historic - Faculty of Sciences - Department of Biological and Physical Sciences
Date Deposited: 30 Nov 2007 11:47
Last Modified: 03 Jul 2013 00:19
Uncontrolled Keywords: magnetic stimulation; brain mapping; recovery; stroke
Fields of Research : 11 Medical and Health Sciences > 1109 Neurosciences > 110906 Sensory Systems
11 Medical and Health Sciences > 1102 Cardiovascular Medicine and Haematology > 110299 Cardiovascular Medicine and Haematology not elsewhere classified
11 Medical and Health Sciences > 1116 Medical Physiology > 111699 Medical Physiology not elsewhere classified
Socio-Economic Objective: C Society > 92 Health > 9201 Clinical Health (Organs, Diseases and Abnormal Conditions) > 920111 Nervous System and Disorders
Identification Number or DOI: 10.1016/S1388-2457(98)00044-3

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