Movement induces suppression of interictal spikes in sensorimotor neocortical epilepsy

Epileptic activities are known to be modulated by cortical excitability, which is altered with normal brain functioning such as movement. However, the relationship between the epileptic activity and movement has not been well studied. Here, we investigated movement-induced modulation of interictal spikes to reveal the relationship between epileptic activity and the movement-induced modulation of cortical activity. Two patients (three cases) with focal cortical dysplasia (FCD) of the pre- and/or post-central gyrus performed voluntary movements of their hands or mouths. During the movement, the interictal spikes of the sensorimotor cortex, which were measured by electrocorticograms (ECoG), were significantly reduced. This reduction strongly correlated with the event-related desynchronization (ERD) of the cortical oscillatory activity at the lower frequency bands (<25 Hz) during movement. The epileptic activity was suggested to be modulated by the movement, which correlates with the ERD of the cortical oscillatory activity.