Abstract

Excitatory Pyramidal Neurons (PN) are the main output source of the Neocortex. These cells are affected by the activity of Interneurons, which display a striking variety of morphologies, neuropeptides, and spiking patterns. The Irregular Spiking (IS) interneuron is of particular interest, displaying a dispersed spiking time when stimulated in vitro, even when synapses are blocked. It could be said that IS interneurons add randomness to the cortical network. The relevance of this irregularity is still unclear. This work aims to address the mechanism and function of this irregularity. We first recorded a population of rat cortical neurons and showed that IS cells only display abnormal interspike intervals (ISI) at frequencies below 15hz. Voltage clamp recordings of IS cells presented a prominent fast transient outward current that may be involved in this intrinsic irregularity. We are next addressing whether this irregularity is influenced by cell morphology via cell dissociation. Future prospects include morphological reconstruction and double whole-cell patch clamp to better understand how IS cells synchronise with each other.