Depolarization block of interneurons

Abstract

In this paper we study the behavior of an hippocampal interneuron model. The mathematical model is the usual Hodgkin-Huxley model modied to reproduce the electrophysiology of these fast-spiking neurons. The synaptic input current is modeled in two ways, one is deterministic the other one is a stochastic process depending on random events. Our results proved that, in presence of large depolarizing input currents, the system undergoes a depolarization block, a phenomenon that has been observed in other kind of neurons. This is an important mechanism which stops sustained neural activity when a neuron receives a strong excitation. However, numerical simulations showed that an inhibitory synaptic current can reactivate neural activity when synaptic current and depolarizing current are a in given interval. We argue that including such mechanism in mathematical models of interneurons can have a signicant impact in the study of epilepsy and other uncontrolled activity of the neurons.