Combined effects of 40 Hz ultrasound and light stimulation on neural oscillations and cognition
Minghui Gao, Shixiong Zhang, Shasha Yi, Yiyue Zhu, Wen Meng, Hairong Zheng, Zhengrong Lin, Lili Niu
Ultrasonics 2026, 160, 107923 · 10.1016/j.ultras.2025.107923
Abstract
Single-modality 40 Hz ultrasound stimulation or 40 Hz light stimulation have demonstrated the efficacy in improving cognitive function in Alzheimer's disease (AD) mice. However, the therapeutic effect of combined 40 Hz ultrasound-light stimulation on AD-related cognitive deficits remain unexplored. To address this gap, we developed a 40 Hz dual-modality stimulation system comprising a dual-targeted holographic ultrasound transducer that enables precise, safe stimulation of the bilateral hippocampal CA1 regions, and a 40 Hz visual stimulation. In wild-type mice, acute 40 Hz ultrasound-light stimulation significantly increased gamma (30-100 Hz) power and cross-regional phase synchronization, revealing a stronger synergistic effect compared to unimodal (ultrasound or light alone) stimulation. In 5XFAD AD model mice, chronic 40 Hz ultrasound-light stimulation robustly improved spatial memory, enhanced gamma phase synchronization and reduced amyloid-β deposition. Our findings demonstrate that this dual-modality strategy serves as a powerful, noninvasive tool to effectively enhance gamma oscillations and mitigate Aβ accumulation, underscoring its promising potential for AD intervention.
Abstract via europepmc.
Exposures
Exposure 1: 40 Hz ultrasound (alone or combined with 40 Hz light) to bilateral hippocampal CA1
Target: CA1 — “bilateral dorsal hippocampal CA1 region”
Device: custom-built · custom-made dual-target holographic ultrasound transducer
| Waveform | pulsed | |
|---|---|---|
| Fundamental frequency (kHz) | 3,300 | ✓✓✓ |
| Pulse duration (ms) | 0.625 | ✓✓✓ |
| Pulse repetition frequency (Hz) | 40 | ✓✓✓ |
| Duty cycle (%) | 2.5pulse duration × PRF gives 2.5% | ✓✓✓⚑ |
| Sonication duration (s) | 1 | ✓✓✓ |
| Free-field pressure (kPa) | not reported | |
|---|---|---|
| Free-field Isppa (W/cm²) | not reported | |
| Free-field Ispta (W/cm²) | not reported | |
| In-situ estimate | not reported | |
| In-situ pressure (kPa) | not reported | |
| In-situ Isppa (W/cm²) | not reported | |
| In-situ Ispta (W/cm²) | not reported |
Ultrasound stimulation parameters: fundamental frequency 3.3 MHz, PRF 40 Hz, duty cycle 2.5%, tone-burst duration 0.625 ms, sonication duration (SD) 1 s, interstimulus interval (ISI) 10 s. Stimulation duration was 30 min/day for 14 days total, synchronised with 40 Hz light stimulation of the same duration/cycle. A prior short-term optimisation experiment tested total daily stimulation durations of 15, 30, and 60 min (US1-3); 30 min (US2) was identified as the optimal condition and used in subsequent long-term/behavioural experiments.
Flags from extraction
n_subjects— The paper reports many different group sizes across sub-experiments only in figure legends (e.g. c-Fos Sham n=5, US n=6; short-term Sham n=19, US1 n=7, US2 n=9, US3 n=6; long-term Sham n=8-10, US2 n=9-13, etc.); no single total number of ultrasound-exposed animals is stated in the main text, so n_subjects is recorded as not_reported.n_sessions_per_subject— The 14-day/30-min-per-day protocol applies to the chronic AD-model behavioural/imaging experiments; separate single-session sub-experiments (c-Fos validation, short-term LFP parameter optimisation) used only one ultrasound session per animal.anaesthesia— Mice underwent surgery under anaesthesia to implant an ultrasound collimator/electrodes, but the paper does not explicitly state whether animals were awake or anaesthetised during the daily ultrasound-light stimulation sessions themselves.exposures[0]— No numeric pressure or intensity (kPa or W/cm2) value is given anywhere in the main text for the ultrasound exposure; only relative/simulated pressure distributions and a qualitative ~40% transcranial attenuation are reported.exposures[0].timing.duty_cycle_pct— Duty cycle (2.5%) and PRF (40 Hz) imply a pulse duration of 0.625 ms, which matches the independently stated tone-burst duration (TBD: 0.625 ms); no discrepancy found.