Integrated ultrasound stimulation and optical imaging of awake mice brain using a transparent ultrasound transducer cranial window
Shubham Mirg, Krishnendu Samanta, Haoyang Chen, Jin Jiang, Kevin L. Turner, Fatemeh Salehi, Kathiravan M. Ramiah, Patrick J. Drew, Sri-Rajasekhar Kothapalli
npj Acoustics 2026 · 10.1038/s44384-025-00037-2
rodenthealthycerebral haemodynamics
Speciesmouse (C57BL/6J)
Subjects3 animals
Sessions per subjectnot reported
Randomisednot reported
Blindingnot reported
Sham / controlactive control site
Auditory controlcontrol experiment
Readout timingonline
Anaesthesiaboth
Readoutscerebral haemodynamics — Laser speckle contrast imaging (% change in CBF) and intrinsic optical signal imaging (change in OD, total haemoglobin)
Direction of effectnot assessedUltrasound increased CBF and total haemoglobin in somatosensory cortex, scaling with pulse train duration and pressure; no consistent dependence on pulse duration or PRF. Neural activity was not recorded.
Adverse eventsnot reportedThermal effects assessed by calculation (maximum tissue rise 0.03 C; transducer surface rise 1.3 C).
Exposures
Exposure 1: Transparent ultrasound transducer cranial window over somatosensory cortex, 12 MHz
Target: somatosensory cortex — “somatosensory cortex”
Device: custom-built · In-house lithium niobate transparent ultrasound transducer (TUT), 3 x 3 mm
| Waveform | pulsed | |
|---|---|---|
| Fundamental frequency (kHz) | 12,000 | ✓✓✓ |
| Pulse duration (ms) | 0.1, 0.5swept | ✓✓✓⚑ |
| Pulse repetition frequency (Hz) | 100, 1,000swept | ✓✓✓ |
| Duty cycle (%) | not reported | ⚑ |
| Sonication duration (s) | 0.025, 0.25swept | ✓✓✓⚑ |
| 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) | 230.8, 486.2swept | ✓✓✓ |
| In-situ Isppa (W/cm²) | 4.9 | ✓✓✓ |
| In-situ Ispta (W/cm²) | not reported |
Protocol, in the paper’s words
Seven trials per recording, 30 s apart; main protocol PRF 1000 Hz, pulse duration 500 us, PNP 486.2 kPa, pulse train duration 250 ms. Pulse train duration varied 25-250 ms, PNP 230.8-486.2 kPa, pulse duration 100-500 us and PRF 100-1000 Hz one at a time.
Flags from extraction
exposures[0].unspecified_domain.pressure_kpa— Peak negative pressure measured by hydrophone in water through a thinned skull and derated 30% for cyanoacrylate glue; domain not clearly stated, so placed in unspecified. Text also gives 496.1 kPa in the PRF sweep, probably a typo for 486.2.exposures[0].unspecified_domain.isppa_w_cm2— Maximum ISPPA only, calculated for mouse brain tissue properties.exposures[0].timing.pulse_duration_ms— Sweep range converted from 100-500 us; values read from text, full parameter table is supplementary.exposures[0].timing.duty_cycle_pct— Duty cycle not stated in the main text.exposures[0].timing.sonication_duration_s— Pulse train duration swept 25-250 ms, converted to s.n_subjects— Three mice for the parameter study; Fig. 2 shows one mouse (n=7 trials).anaesthesia— Main experiments in awake head-fixed mice; an isoflurane comparison is in supplementary material.sham_type— Sham ultrasound with the same parameters delivered over the frontal bone, plus a 1 kHz auditory stimulus; shown in supplementary figure.