Spike Onset Dynamics and Response Speed in Neuronal Populations

TL;DR

This paper introduces a neuron model with dynamic spike initiation, revealing that faster initiation times can significantly increase the frequency range of neuronal response, aligning with experimental observations.

Contribution

The study provides an analytical framework for understanding how spike onset dynamics influence neuronal response speed and cutoff frequency.

Findings

Cutoff frequencies can reach very high values with rapid spike initiation.

The model explains high-frequency encoding observed in cortical neurons.

Analytical response calculations match experimental data.

Abstract

Recent studies of cortical neurons driven by fluctuating currents revealed cutoff frequencies for action potential encoding of several hundred Hz. Theoretical studies of biophysical neuron models have predicted a much lower cutoff frequency of the order of average firing rate or the inverse membrane time constant. The biophysical origin of the observed high cutoff frequencies is thus not well understood. Here we introduce a neuron model with dynamical action potential generation, in which the linear response can be analytically calculated for uncorrelated synaptic noise. We find that the cutoff frequencies increase to very large values when the time scale of action potential initiation becomes short.