Localization of ultrasound induced in-vivo neurostimulation in the mouse model

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. The phenomenon of ultrasound induced neurostimulation has a long history dating back many decades, but until now there has been little evidence demonstrating 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 EMG 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 for being able 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.