Firing regulation of fast-spiking interneurons by autaptic inhibition

TL;DR

This study uses computational models to explore how autaptic inhibition influences the firing behavior of fast-spiking interneurons, revealing its role in regulating firing thresholds, gain, and response to noise.

Contribution

It provides new insights into the functional impact of autaptic inhibition on FS interneuron firing dynamics through computational analysis.

Findings

Autaptic inhibition increases the current threshold for firing.

Autaptic delay controls firing patterns and multistability.

Noise influences firing regularity and extends dynamic range.

Abstract

Fast-spiking (FS) interneurons in the brain are self-innervated by powerful inhibitory GABAergic autaptic connections. By computational modelling, we investigate how autaptic inhibition regulates the firing response of such interneurons. Our results indicate that autaptic inhibition both boosts the current threshold for action potential generation as well as modulates the input-output gain of FS interneurons. The autaptic transmission delay is identified as a key parameter that controls the firing patterns and determines multistability regions of FS interneurons. Furthermore, we observe that neuronal noise influences the firing regulation of FS interneurons by autaptic inhibition and extends their dynamic range for encoding inputs. Importantly, autaptic inhibition modulates noise-induced irregular firing of FS interneurons, such that coherent firing appears at an optimal autaptic inhibition level. Our result reveal the functional roles of autaptic inhibition in taming the firing dynamics of FS interneurons.