Transcranial ultrasound stimulation modulates neuronal membrane potentials across broad timescales in the awake mammalian brain
Emma Bortz, Erynne San Antonio, Jack Sherman, Hua-an Tseng, Laura Raiff, Xue Han
Brain Stimulation 2025, 18, 1726-1740 · 10.1016/j.brs.2025.09.004
Abstract
Background Transcranial ultrasound stimulation (TUS) offers noninvasive neuromodulation with high spatiotemporal precision, but its cellular-level effects in the awake brain remain poorly understood. Objective We investigated how low-intensity TUS modulates membrane voltage dynamics in individual cortical neurons in awake mice. Methods Using the genetically encoded voltage indicator SomArchon, we performed high-speed kilohertz voltage imaging in awake head-fixed mice. TUS was delivered with a 0.35 MHz transducer at 10 or 40 Hz pulse repetition frequency, at intensities below the estimated threshold for auditory brainstem activation. We analyzed changes in membrane potentials (Vm), spiking, and coordination across simultaneously recorded neurons. Results TUS evoked rapid ( Conclusion By resolving single-neuron responses in the awake mammalian brain, our results demonstrate that TUS directly activates individual cortical neurons with latencies often shorter than 10 ms. TUS pulsed at physiologically relevant frequencies of 10 and 40 Hz robustly entrains neural dynamics, alters network coordination and evokes neuronal plasticity. These results highlight the therapeutic potential of designing TUS pulsing patterns to target desired neural dynamics and plasticity features.
Abstract via europepmc.
Exposures
Exposure 1: TUS to motor/visual cortex neurons via sub-chin transducer
Target: primary motor cortex, primary visual cortex — “motor cortex or visual cortex (craniotomy/imaging site)”
Device: Ultran · Ultran · GS350-D13 ✓
| Waveform | pulsed | |
|---|---|---|
| Fundamental frequency (kHz) | 350 | ✓✓✓ |
| Pulse duration (ms) | 20, 5swept | ✓✓✓ |
| Pulse repetition frequency (Hz) | 10, 40swept | ✓✓✓ |
| Duty cycle (%) | 20 | ✓✓✓ |
| Sonication duration (s) | 1 | ✓✓✓ |
| Free-field pressure (kPa) | 401 | ✓✓✓ |
|---|---|---|
| Free-field Isppa (W/cm²) | not reported | |
| Free-field Ispta (W/cm²) | not reported | |
| In-situ estimate | simulationsingle value | |
| In-situ pressure (kPa) | 110 | ✓✓✓⚑ |
| In-situ Isppa (W/cm²) | 0.129 | ✓✓✓ |
| In-situ Ispta (W/cm²) | not reported |
Each recording trial was 3 s in duration, comprising a 1-s pre-stimulation baseline with the transducer off, 1-s of ultrasound stimulation at either 10 or 40 Hz PRF with a 20% duty cycle, and a 1-s post-stimulation with the transducer off. Each neuron was typically recorded over 20 trials (range: 10-40), with an inter-trial interval of ~2-10 s.
Consistency checks: intensity pressure inconsistent in situ.
Flags from extraction
n_subjects— Study included 20 total mice; 161 neurons recorded from 15 mice received real TUS (n_subjects reported here), while a separate 5 mice contributed 60 neurons under sham (off-target abdominal) ultrasound only. The paper does not explicitly confirm whether the sham mice were a fully distinct set from the 20 total or drawn from the same pool with different sessions.exposures[0].in_situ.pressure_kpa— Body text states a simulated peak pressure of 0.11 MPa (110 kPa) at the imaging site, used to derive the reported in situ ISPPA; however, the Figure 1 caption reports a different simulated in-situ peak pressure of 209 kPa, and the text separately reports 0.18 MPa (180 kPa) at the intracranial bone. These three values are inconsistent; the imaging-site body-text value is used here.target— The sub-chin transducer is unfocused/broad relative to the mouse brain and its position was not adjusted between motor-cortex and visual-cortex recording sessions; both target regions are listed for the single exposure rather than splitting into two exposures.auditory_control— No masking sound, ramping, or deafening was used; instead the authors selected sub-auditory-threshold intensity based on a computational auditory brainstem response (ABR) prediction model (Choi et al.) and used an off-target sham to rule out auditory/systemic confounds.