Abstracts

RATIONALE:_ Functional mapping of cortex is necessary before a surgical treatment of epilepsy. Actually, this mapping depends essentially on intracerebral stimulations. We used the method of quantification of event-related desynchronization (ERD) and synchronization to analyze the reactivity of intracerebral rhythms recorded from depth electrodes during the preparation and execution of a simple self-paced movement of the contralateral hand. METHODS:_We recorded 3 patients presenting with a refractory frontal lobe epilepsy which were explored by stereoelectroencephalography before a surgical treatment. The electrodes explored the precentral gyrus, the postcentral gyrus, the frontomesial and frontolateral cortex which were spared by the lesion. RESULTS:_We observed a mu and beta desynchronization beginning before the movement onset in the posterior bank of the precentral gyrus. At the movement onset, this desynchronization spread to the postcentral gyrus and to the frontomesial cortex. The involvement of the premotor frontolateral cortex was inconstant and occurred later than that of the motor and sensory areas. CONCLUSIONS:_Our data suggest that the temporal evolution of rhythms reactivity varies with the functional areas. So it seems possible to use the method of ERD to localize the electrodes and to perform a functional mapping of sensorimotor cortex.