Wilson S A, Thickbroom G W, Mastaglia F L
Australian Neuromuscular Research Institute, Perth, Australia.
Electroencephalogr Clin Neurophysiol. 1995 Oct;97(5):246-50. doi: 10.1016/0013-4694(95)00052-z.
This study has compared the topography of the corticomotor representation of an intrinsic hand muscle in the relaxed state and during a low-level voluntary contraction using transcranial magnetic stimulation. It was found that the optimum cortical stimulus site and the surrounding area of excitable cortex were shifted approximately 6 mm medially as a result of performing a voluntary contraction. This difference may be due to a combination of factors involving the spatial distribution of excitable intracortical fibres, the effects of muscle afferent activity on motor cortex excitability, and task-dependent modifications of corticomotor output.
