Dynamic interneuron-principal cell interplay leads to a specific pattern of in vitro ictogenesis.

Dynamic interneuron-principal cell interplay leads to a specific pattern of in vitro ictogenesis.
Neurobiol Dis. 2018 Apr 07;:
Authors: Lévesque M, Chen LY, Hamidi S, Avoli M
Abstract
Ictal discharges induced by 4-aminopyridine in the in vitro rodent entorhinal cortex present with either low-voltage fast or sudden onset patterns. The role of interneurons in initiating low-voltage fast onset ictal discharges is well established but the processes leading to sudden onset ictal discharges remain unclear. We analysed here the participation of interneurons (n = 75) and principal cells (n = 13) in the sudden onset pattern by employing in vitro tetrode wire recordings in the entorhinal cortex of brain slices from Sprague-Dawley rats. Ictal discharges emerged from a background of frequently occurring interictal spikes that were associated to a specific interneuron/principal cell interplay. High rates of interneuron firing occurred 12 ms before interictal spike onset while principal cells fired later during low interneuron firing. In contrast, the onset of sudden ictal discharges was characterized by increased firing from principal cells 627 ms before ictal onset whereas interneurons increased their firing rates 161 ms before ictal onset. Our data show that sudden onset ictogenesis is associated with frequently occurring interictal spikes resting on the interplay between interneurons and principal cells while ictal discharges st...

Source: Neurobiology of Disease - April 7, 2018 Category: Neurology Authors: Lévesque M, Chen LY, Hamidi S, Avoli M Tags: Neurobiol Dis Source Type: research