Localization of Ultrasound-Induced In Vivo Neurostimulation in the Mouse Model
Randy L. King, Julian R. Brown, Kim Butts Pauly
Ultrasound in Medicine & Biology 2014 · 10.1016/j.ultrasmedbio.2014.01.020
Abstract
Developments in the use of ultrasound to stimulate and modulate neural activity have raised the possibility of using ultrasound as a new investigative and therapeutic tool in brain research. Although the phenomenon of ultrasound-induced neurostimulation has a long history dating back many decades, until now there has been little evidence of a clearly localized effect in the brain, a necessary requirement for the technique to become genuinely useful. Here we report clearly distinguishable effects in sonicating rostral and caudal regions of the mouse motor cortex. Motor responses measured by normalized electromyography in the neck and tail regions changed significantly when sonicating the two different areas of motor cortex. Response latencies varied significantly according to sonication location, suggesting that different neural circuits are activated depending on the precise focus of the ultrasound beam. Taken together, our findings present good evidence of the ability to target selective parts of the motor cortex with ultrasound neurostimulation in the mouse, an advance that should help to set the stage for developing new applications in larger animal models, including humans.
Abstract via europepmc.
Exposures
Exposure 1: Rostral and caudal mouse motor cortex, 80 ms CW at 500 kHz
Target: motor cortex — “rostral and caudal regions of the mouse motor cortex”
Device: Olympus / Panametrics · Olympus · V301 ✓
| Waveform | continuous | |
|---|---|---|
| Fundamental frequency (kHz) | 500 | ✓✓✓ |
| Pulse duration (ms) | not applicable | |
| Pulse repetition frequency (Hz) | not applicable | |
| Duty cycle (%) | not applicable | |
| Sonication duration (s) | 0.08 | ✓✓✓ |
| Free-field pressure (kPa) | 200 | ✓✓✓⚑ |
|---|---|---|
| Free-field Isppa (W/cm²) | 3 | ✓✓✓⚑ |
| 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 |
All experiments were conducted using 80-ms continuous wave ultrasound sonications. Sonications were delivered in pseudo-random sequence with a minimum interval of 5 s, only during quiescence in muscle activity; sham sonications at 0 W/cm2 were interleaved in 4 of 10 mice.
Consistency checks: intensity pressure inconsistent free field.
Flags from extraction
exposures[0].free_field.isppa_w_cm2— Paper says only 'intensity of 3 W/cm2' and does not name the metric; placed under isppa by assumption. Calculated from hydrophone scans in a scanning tank, skull ignored, so recorded as free field.species— Paper writes 'CBL-7 mice'; probably C57BL/6 but recorded as written.exposures[0].free_field.pressure_kpa— 0.2 MPa stated in parentheses beside the intensity; converted to 200 kPa.sham_type— Sham was 0 W/cm2 sonications; mechanism not described beyond zero intensity.exposures[0].timing.protocol_description— Intensity varied 0.7 to 3 W/cm2 only during site-finding; main experiment at 3 W/cm2.