KINDLING IN THE PERIRHINAL CORTEX

In vitro experiments have indicated that the perirhinal cortex is high ly excitable and its relationship to the basolateral amygdala and piri form cortex is altered by previous amygdala or dorsal hippocampal kind ling17,18. As a result, we felt it was important to assess the excitab ility of the perirhinal cortex in vivo by comparing its kindling profi le to that of the basal amygdala, piriform cortex or dorsal hippocampu s. We observed that the after-discharge (AD) threshold of the perirhin al cortex was higher than the other 3 structures but the AD duration w as not different. Subsequently, the perirhinal cortex kindled more rap idly than the other 3 structures, and with extremely short latencies t o onset of forelimb clonus. With the view that synchronized discharge in the perirhinal-piriform area provides the critical trigger for limb ic kindled convulsions, the relationship of kindling rate and convulsi on latencies and durations between the 4 structures was discussed.