Transcranial Focused Ultrasound Stimulation of the Primary Somatosensory Cortex Evokes Hand Tactile Perception: The Effect of Sonication Duration
Xu-Xu CHEN, Huan-Jun XI, Zhen LIANG, Bo WANG, Xu-Dong ZHAO
Progress in Biochemistry and Biophysics 2026 · 10.3724/j.pibb.2025.0503
human healthyhealthybehaviour
Specieshuman
Subjects48 participants
Sessions per subjectnot reported
Randomisedyes
Blindingnot reported
Sham / controlinactive transducer, undescribed
Auditory controlnot reported
Readout timingonline
Anaesthesianot applicable
Readoutsbehaviour — tactile localization accuracy (perceptual consistency rate); self-reported sensation types
Direction of effectexcitatoryActive S1 stimulation evoked contralateral hand tactile sensations localised above chance (0.613 vs 0.5); in Experiment 2 consistency exceeded chance at 400 and 1000 ms sonication durations but not at 200, 600 or 800 ms.
Adverse eventsnot reportedExperimenter asked about scalp sensations at the midpoint and end of the session; temperature measurements reported to confirm heating within safe limits.
Exposures
Exposure 1: Bilateral S1 tFUS, five sonication durations
Target: primary somatosensory cortex — “left and right S1, with MNI coordinates of (-60, -31, 52) and (60, -31, 52)”
Device: not reported · transducer CO.5MD-1R50-048; stimulator GCBT-1-A001 (Zhongke Lvgu Inc.) ✓
| Waveform | pulsed | |
|---|---|---|
| Fundamental frequency (kHz) | 500 | ✓✓✓ |
| Pulse duration (ms) | 0.2 | ✓✓✓⚑ |
| Pulse repetition frequency (Hz) | 1,000 | ✓✓✓ |
| Duty cycle (%) | 50pulse duration × PRF gives 20%, which disagrees with the stated value | ✓✓✓⚑ |
| Sonication duration (s) | 0.2, 0.4, 0.6, 0.8, 1swept | ✓✓✓⚑ |
| 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 | |
| Pressure, domain unspecified (kPa) | 892 | ✓✓✓⚑ |
| Isppa, domain unspecified (W/cm²) | 6.63 | ✓✓✓ |
Protocol, in the paper’s words
Pulse width 0.2 ms, pulse repetition period 1 ms (PRF 1 kHz); Experiment 2 states DC 50% and PD 10 ms with five sonication durations (200-1000 ms), 10 trials per duration per side, 6 s inter-stimulus interval.
Consistency checks: intensity pressure inconsistent unspecified domain.
Flags from extraction
exposures[0].timing.pulse_duration_ms— Text states pulse width 0.2 ms with 1 kHz PRF, but also DC 50% (which would imply 0.5 ms) and 'pulse duration (PD) 10 ms' in the ultrasound setup; values are mutually inconsistent, recorded as stated (0.2 ms).exposures[0].timing.duty_cycle_pct— 50% duty cycle conflicts with 0.2 ms pulse width at 1 kHz PRF.exposures[0].unspecified_domain.pressure_kpa— Peak rarefactional pressure 0.892 MPa and Isppa 6.63 W/cm2 given without stating water or in situ.exposures[0].timing.sonication_duration_s— Durations given in ms (200-1000) converted to s; five-level sweep.randomised— Stimulation order randomised in Experiment 1a; Experiment 2 used predefined counterbalanced order; participant allocation not randomised.exposures[0].device.family— Transducer maker not named; only stimulator maker (Zhongke Lvgu Inc.) given.sham_type— Experiment 2 sham probe emitted no ultrasound; Experiment 1b sham stimulation not described.