It sounds like an action potential: unification of electrical, chemical and mechanical aspects of acoustic pulses in lipids

TL;DR

This paper proposes a unified physical model of action potentials as acoustic pulses in lipid interfaces, integrating electrical, chemical, and mechanical aspects, challenging traditional electrical-only views.

Contribution

It introduces a parameter-free physical model that unifies electrical, chemical, and mechanical features of action potentials as acoustic pulses in lipids.

Findings

Model reproduces shape, scale, and velocity of action potentials.

Demonstrates amplitude saturation and pulse collision annihilation.

Shows electrical and pH changes emerge from mechanical acoustic pulses.

Abstract

In an ongoing debate on the physical nature of the action potential, one group adheres to the electrical model of Hodgkin and Huxley, while the other describes the action potential as a non-linear acoustic pulse propagating within an interface near a transition. However, despite remarkable similarities, acoustics remains a non-intuitive mechanism for action potentials for the following reason. While acoustic pulses are typically associated with the propagation of density, pressure and temperature variation, action potentials are most commonly measured electrically. Here, we show that this discrepancy is lifted upon considering the electrical and chemical aspects of the interface, in addition to its mechanical properties. Specifically, we demonstrate how electrical and pH aspects of acoustic pulses emerge from an idealized description of the lipid interface, which is based on classical physical principles and contains no fit parameters. The pulses that emerge from the model show striking similarities to action potentials not only in qualitative shape and scales (time, velocity and voltage), but also demonstrate saturation of amplitude and annihilation upon collision.