A polydimethylsiloxane-based axicon lens for focused ultrasonic brain stimulation techniques
Fabin Acquaticci, Juan F. Guarracino, Sergio N. Gwirc, Sergio E. Lew
Acoustical Science and Technology 2019 · 10.1250/ast.40.116
rodenthealthybehaviour
Speciesmouse (CF-1)
Subjects3 animals
Sessions per subjectnot reported
Randomisednot reported
Blindingnot reported
Sham / controlnone
Auditory controlnot reported
Readout timingonline
Anaesthesiaanaesthetised
Readoutsbehaviour — Visually observed evoked muscle movements (tail, hindlimb, forelimb)
Direction of effectexcitatoryAxicon-lens tFUS of the mouse motor cortex evoked movement in a specific body segment (tail at the mapped site); US intensity was raised until a movement threshold was seen.
Adverse eventsnone observedNormal behaviour observed in all animals after sonication; intensity stated to be below FDA imaging limits.
Exposures
Exposure 1: Axicon-lens tFUS of mouse motor cortex
Target: motor cortex — “motor cortex (area related to the control of tail motility)”
Device: custom-built · Prototype built in-house with a Steminc piezo-disc element · tFUS-axicon transducer, 445 kHz, epoxy/PDMS axicon lens ✓
| Waveform | pulsed | |
|---|---|---|
| Fundamental frequency (kHz) | 445 | ✓✓✓ |
| Pulse duration (ms) | 0.36 | ✓✓✓ |
| Pulse repetition frequency (Hz) | 1,000 | ✓✓✓ |
| Duty cycle (%) | not reportedpulse duration × PRF gives 36% | |
| Sonication duration (s) | not reported | ⚑ |
| Free-field pressure (kPa) | not reported | |
|---|---|---|
| Free-field Isppa (W/cm²) | not reported | |
| Free-field Ispta (W/cm²) | 0.036 | ✓✓✓ |
| 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) | 100 | ✓✓✓⚑ |
Protocol, in the paper’s words
Motor cortex stimulated every 3 s with a train of low-intensity tFUS pulses (PD 0.36 ms, PRF 1 kHz); intensity was gradually increased at each site until movement was detected. Number of pulses per train (stimulus duration) not stated.
Flags from extraction
exposures[0].unspecified_domain.ispta_w_cm2— 36 mW/cm2 converted to 0.036 W/cm2; domain not stated (radiant-force power meter; skull effect ignored); also used for mapping at threshold, so may not apply to all conditions.exposures[0].unspecified_domain.pressure_kpa— 0.1 MPa given as 'small peak pressure amplitude' in the discussion; domain not stated and not obviously consistent with 36 mW/cm2 Ispta.exposures[0].timing.sonication_duration_s— Stimulus duration and number of pulses are not given.exposures[0].device.manufacturer— Transducer built in-house; manufacturer field describes the build, piezo element from Steminc.