This study uses magnetoencephalography (MEG) to examine whether cortical regions that constitute a default mode network are involved during generalized spike-wave discharges (GSWs) in patients with juvenile absence epilepsy (JAE). We studied five JAE patients for whom MEG was recorded using a 204-channel, whole-head gradiometer system. Dynamic statistical parametric mapping (dSPM) was done to estimate the cortical source distribution of GSW. The dSPM results showed strong medial prefrontal activation in all patients, with activation in the posterior cingulate and precuneus in three of five patients simultaneously or slightly after medial prefrontal activation. Furthermore, dSPM showed that the initial activation of a GSW appears in the focal cortical regions. Cortical regions that constitute a default mode network are strongly involved in the GSW process in some patients with JAE. Results also show that focal cortical activation appears at the onset of a GSW.
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