Generators of rolandic discharges in a patient with a typical benign rolandic epilepsy

We investigated the rolandic discharges (RDs) in a patient with a typical benign rolandic epilepsy using a 37-channel magnetoencephalography (MEG). In the present patient, we pointed out a similarity between the RD and somatosensory evoked potentials (SEP) deflections in terms of a wave form, topography, and time relationship. We also showed that the current source of the RD and giant middle-latency components (MLCs), N2m and P2m, in somatosensory evoked magnetic fields (SEF) are almost consistently localized in the primary sensory cortex (SI). The second deflection in SEE P1m was also enhanced, while in the first deflection N1m was not. Thus the RDs in our patient are thought to be triggered by the enhanced P1m, which is followed by the giant MLCs, N2m and P2m. Our data suggest that RDs generator mechanism may be related to hyperexcitability of SI and it may share a common neuronal pathway, at least in part with the giant MLCs in SEF and SEP.