Analysis of Neural Activation in Time-dependent Membrane Capacitance Models

TL;DR

This paper investigates how time-dependent membrane capacitance influences neuron excitability, revealing that abrupt and significant capacitance changes can trigger action potentials, impacting neuromodulation techniques.

Contribution

It introduces a modified neuron model with dynamic capacitance and demonstrates conditions under which action potentials are generated due to capacitance variations.

Findings

Significant and abrupt capacitance variations are needed to generate action potentials.

Explicit simple capacitance profiles with strong variations can elicit action potentials.

Frequent abrupt changes in capacitance may suppress action potential generation.

Abstract

Most models of neurons incorporate a capacitor to account for the marked capacitive behavior exhibited by the cell membrane. However, such capacitance is widely considered constant, thereby neglecting the possible effects of time-dependent membrane capacitance on neural excitability. This study presents a modified formulation of a neuron model with time-dependent membrane capacitance and shows that action potentials can be elicited for certain capacitance dynamics. Our main results can be summarized as: (a) it is necessary to have significant and abrupt variations in the capacitance to generate action potentials; (b) certain simple and explicitly constructed capacitance profiles with strong variations do generate action potentials; (c) forcing abrupt changes in the capacitance too frequently may result in no action potentials. These findings can have great implications for the design of ultrasound-based or other neuromodulation strategies acting through transiently altering the membrane capacitance of neurons.