Revision 1

Accepted · first revision · record

Title: How focused ultrasound changes neural activity
Plain: Low-intensity sound aimed at the brain changes how neurons fire, and the reason is disputed. Part of the measured effect may come from the subject simply hearing the pulse.
Precise: Identify the mechanism by which focused ultrasound at $0.2\ \text{to}\ 1.5\ \mathrm{MHz}$, spatial-peak pulse-average intensity below about $10^8\ \mathrm{erg}/(\mathrm{s}\ \mathrm{cm}^{2})$ and mechanical index below 1, modulates neuronal firing. Candidates: radiation force and membrane strain, intramembrane cavitation, mechanosensitive ion channel activation, local heating of order $0.1\ \mathrm{K}$, and indirect auditory activation. An answer is a mechanism predicting the sign and magnitude of the effect versus frequency, pulse length and duty cycle.
Settled by: Experiments with auditory confound removed, varying frequency and pulse parameters independently, with simultaneous measurement of displacement, temperature and neural response.
Kind: phenomenon
Answer type: mechanism
References: (empty)
Literature status: contested
Status note: Auditory confounding demonstrated in rodents in 2018 forced reinterpretation of earlier results; no consensus mechanism as of 2025.
Posed since: 2008