PERIRHINAL CORTEX INVOLVEMENT IN LIMBIC KINDLED SEIZURES

Investigations into the anatomical substrate of temporal lobe epilepsy have yielded a number of important observations regarding the involve ment of the piriform and perirhinal cortical areas in temporal lobe se izure propagation. Although early reports indirectly suggested that th e circuits of the piriform cortex might act as a critical conduit for Limbic seizure discharges to access motor systems, recent reports more strongly implicate the perirhinal cortex in this process. In the foll owing report, we provide a brief summary of the earlier work involving the piriform cortex and its potential involvement in kindled limbic s eizures. This is followed then by the results of several recent in viv o and in vitro electrophysiological studies that ascribe a critical im portance for the perirhinal cortex in convulsive limbic seizures. Fina lly, since our anatomical studies indicated that the perirhinal cortex densely innervates the frontal motor cortex, we examined the involvem ent of this latter region in amygdala kindled seizures using the rever sible functional lesion of cortical spreading depression. Based on the se findings we suggest that the circuits of the perirhinal cortex may be important in the amplification and distribution of temporal lobe se izure discharges, providing access to structures that are capable of d riving a convulsive response.