Low-intensity transcranial ultrasound stimulation modulates neural activities in mice under propofol anaesthesia.

Authors: Liu M, Yuan Y, Wang X, Wang T, Bian N, Zhao L, Cui G, Liu W, Ma Z, Yang X, Liang S, Liu Z

Previous studies have reported that transcranial focused ultrasound stimulation can significantly decrease the time to emergence from intraperitoneal ketamine-xylazine anaesthesia in rats. However, how transcranial focused ultrasound stimulation modulates neural activity in anaesthetized rats is unclear. In this study, to answer this question, we used low-intensity transcranial ultrasound stimulation (TUS) to stimulate the brain tissue of propofol-anaesthetized mice, recorded local field potentials (LFPs) in the mouse motor cortex and electromyography (EMG) signals from the mouse neck, and analysed the emergence and recovery time, mean absolute power, relative power and entropy of local field potentials. We found that the time to emergence from anaesthesia in the TUS group (20.3 ± 1.7 min) was significantly less than that in the Sham group (32 ± 2.6 min). We also found that compared with the Sham group, 20 min after low-intensity TUS during recovery from anaesthesia, (1) the absolute power of local field potentials in mice was significantly reduced in the [1-4 Hz] and [13-30 Hz] frequency bands and significantly increased in the [55-100 Hz], [100-140 Hz] and [140-200 Hz] frequency bands; (2) the relative power of local field potentials in mice was enhanced at [30-45 Hz], [100-140 Hz] and [140-200 Hz] frequency bands; (3) the entropy of local field potentials ([1-200 Hz]) was increased. These results demonstrate that low-intensity TUS can effectively modulate neural activities in both awake and anaesthetized mice and has a positive effect on recovery from propofol anaesthesia in mice.

Introduction

Purpose Transcranial ultrasound stimulation

Study Objective To determine how low-intensity transcranial ultrasound stimulation (TUS) modulates neural activity and influences emergence and recovery from propofol anesthesia in mice.

Animal model / Human subject Mice (species: mouse; strain: None; age: None; sex: None)

Disease model Healthy

Targeted brain region(s) Mouse Motor Cortex

Cargo name and characteristics Propofol — small-molecule intravenous/general anesthetic used to induce and maintain anaesthesia in mice; Low-intensity transcranial ultrasound stimulation (TUS) — physical neuromodulation stimulus (non-molecular, no cargo)

Outcomes and Safety

Summary of Outcomes Low‑intensity transcranial ultrasound stimulation (single stimulation parameter) significantly shortened time-to-emergence from propofol anesthesia in mice (20.3 ± 1.7 min vs 32 ± 2.6 min) and altered motor-cortex neural activity: it decreased absolute LFP power in 1–4 Hz and 13–30 Hz bands and increased absolute power in 55–100 Hz, 100–140 Hz and 140–200 Hz bands, increased relative power in 30–45 Hz, 100–140 Hz and 140–200 Hz bands, and increased LFP entropy (1–200 Hz).

Duration of biological effect 20 min

Safety-related matter No adverse effects or safety issues were reported in the study; the authors did not mention tissue damage or other harms from low-intensity TUS, though they note human studies are still at an early stage.

Brain Region

Ultrasound Parameters

Focal Characteristics Focal depth: None; Focal length: None; Aperture size: None

Treatment frequency Single

We are open to feedback. If you see a mistake or have a suggestion, please contact us.