Intraoperative unmasking of brain redundant motor sites during resection of a precentral angioma: evidence using direct cortical stimulation.

We report the first observation of real-time intraoperative evidence of a retrocentral redistribution of motor areas with an unmasking of precentral redundant motor sites, before and after, respectively, surgical removal of a precentral arteriovenous malformation using direct electrical stimulation. This study shows large-scale plasticity of the motor function behind the central sulcus as the result of an arteriovenous malformation, the brain's ability to effect short-term unmasking of precentral motor sites after arteriovenous malformation resection, and the existence of redundant precentral and postcentral motor areas for the same movement, suggesting that the central sulcus does not simply divide motor and sensory functions.