{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"015081aa3c0bd83a21e1c9060deac2e525e1d855630ab07c9bdc573f6bed9f6d","created":"2026-10-03T07:18:06Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"9c22eeb9561319a41f5552b1af4050a8b68faa8c7b5791378ea879c13c75dc47","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"mechanism","assisted_by":[],"external_id":"med.focused-ultrasound.neuromodulation-mechanism","kind":"phenomenon","literature_status":"contested","n":"1","parents":[],"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.","posed_since":"2008","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.","problem_ref":null,"references":"","settled_by":"Experiments with auditory confound removed, varying frequency and pulse parameters independently, with simultaneous measurement of displacement, temperature and neural response.","status_note":"Auditory confounding demonstrated in rodents in 2018 forced reinterpretation of earlier results; no consensus mechanism as of 2025.","title":"How focused ultrasound changes neural activity","topic_ref":"8f240ebd4ecd5f8e303bb3f92d02a60c846c51e2ff4c97cf08dac7930e62b3b4"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"72838bb0075f9ed93fbb7e246fff6c4cd303702b700d2e7cd552e4afbebe1e7f","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"5b146673ea729f0257b02717a42b99a07ec239c91d11f216a5840af5a09126ef","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"VPjP3Q9egNZCFb58JNwwBgim3wYnetgQ_Hc5Qs0NCdwJvJv1InJw5HGX6pVVauPtmZmXlR7lcafrIFd8yJVnCA"},"schema":"pubphys.envelope/1"},"record_hash":"72838bb0075f9ed93fbb7e246fff6c4cd303702b700d2e7cd552e4afbebe1e7f","leaf_index":1687}