Neuromodulation Effects of Ultrasound Stimulation Under Different Parameters on Mouse Motor Cortex
Xingran Wang, Jiaqing Yan, Zhijie Wang, Xiaoli Li, Yi Yuan
IEEE Transactions on Biomedical Engineering 2020, 67, 291-297 · 10.1109/tbme.2019.2912840
Abstract
Objective Although low-intensity transcranial ultrasound stimulation (TUS) enhances/suppresses neural oscillations and causes electroencephalography changes in the motor cortex, researchers have not clearly determined the manner in which the relative power and entropy of neural oscillations in the motor cortex vary with ultrasonic parameters, such as ultrasound intensity, stimulation duration (SD), and duty cycle. Methods In this paper, we use the transcranial ultrasound of different parameters to stimulate the mouse motor cortex, cause tail muscle contraction and movement, and simultaneously record local field potentials (LFPs) in the mouse motor cortex. The relative power and entropy of the LFPs under different ultrasonic parameters are analyzed. Results The relative power of the theta [4-8 Hz] frequency bands decreases with an increase in spatial-peak and pulse-average intensity (I sppa ) at 0-0.5 s and 0.5-1 s; the relative power of the gamma [30-45 Hz] frequency bands increases with an increase in I sppa at 0-0.5 s and 0.5-1 s; the relative power each of the gamma [30-45 Hz] and high gamma [55-100 Hz] frequency bands increases with an increase in the SD at 0-0.5 s and 0.5-1 s; the entropy values decrease with increases in I sppa and SD at 0-0.5 s. Conclusion The relative power and entropy of neural oscillations in the motor cortex can be modulated by TUS with different parameters, namely, ultrasound intensity and stimulation duration.
Abstract via europepmc.
Exposures
Exposure 1: TUS of mouse motor cortex, sweep of intensity/duration/duty cycle
Target: motor cortex — “motor cortex”
Device: Olympus / Panametrics · Olympus, USA · V301-SU ✓
| Waveform | pulsed | |
|---|---|---|
| Fundamental frequency (kHz) | 500 | ✓✓✓ |
| Pulse duration (ms) | not reported | |
| Pulse repetition frequency (Hz) | 1,000 | ✓✓✓ |
| Duty cycle (%) | 10, 20, 30, 40swept | ✓✓✓ |
| Sonication duration (s) | 0.1, 0.2, 0.3, 0.4swept | ✓✓✓ |
| 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 | |
| Isppa, domain unspecified (W/cm²) | 0.2, 0.4, 0.8, 1.1swept | ✓?⚑ |
The FF and PRF of the ultrasound were 500 and 1 kHz, respectively. Other combinations of the ultrasound parameters Isppa, SD, and DC are displayed in Table I. The other ultrasonic parameters remained unchanged so that we could quantitatively analyze the changes in parameters of LFP with a single ultrasonic parameter. TUS group (19 mice): The mice in the TUS group were used to analyze the effects of TUS of different parameters on neural oscillations.
Flags from extraction
n_subjects— 33 mice were used in total (19 TUS, 5 sham, 9 dead-animal control for electrode-vibration noise); n_subjects reports only the active TUS group since sham/control did not receive brain-penetrating stimulation intended to modulate neural activity.exposures[0].sham_type— Sham group received real ultrasound output but with the collimator oriented parallel to the skull so the wave would not penetrate into brain tissue; classified as inactive_transducer (aimed away) but mechanism differs from a powered-off transducer.exposures[0].unspecified_domain.isppa_w_cm2— Field distribution (kPa) was measured 'under the skull' by hydrophone (ex vivo skull), but the paper does not explicitly state whether the reported Isppa sweep values are free-field or in-situ/through-skull; domain left unspecified.