Diversity of Intrinsic Frequency Encoding Patterns in Rat Cortical Neurons -Mechanisms and Possible Functions

TL;DR

This study investigates diverse intrinsic firing patterns in rat cortical neurons, proposing a simple model to explain their mechanisms and suggesting that network connections enhance encoding gain, which may improve signal detection.

Contribution

The paper introduces a leaky integrate-and-fire model with sinusoidal input to explain diverse neuronal firing patterns and highlights the role of network connections in enhancing encoding.

Findings

Neurons exhibit increasing, decreasing, or constant firing patterns in response to oscillatory input.

A simple leaky integrate-and-fire model can replicate these diverse responses.

Network connections among neurons can enhance encoding gain.

Abstract

Extracellular recordings of single neurons in primary and secondary somatosensory cortices of monkeys in vivo have shown that their firing rate can increase, decrease, or remain constant in different cells, as the external stimulus frequency increases. We observed similar intrinsic firing patterns (increasing, decreasing or constant) in rat somatosensory cortex in vitro, when stimulated with oscillatory input using conductance injection (dynamic clamp). The underlying mechanism of this observation is not obvious, and presents a challenge for mathematical modelling. We propose a simple principle for describing this phenomenon using a leaky integrate-and-fire model with sinusoidal input, an intrinsic oscillation and Poisson noise. Additional enhancement of the gain of encoding could be achieved by local network connections amongst diverse intrinsic response patterns. Our work sheds light on the possible cellular and network mechanisms underlying these opposing neuronal responses, which serve to enhance signal detection.