Safety, Parameterization, and Mechanism of Transcranial Focused Ultrasound (fUS) Over the Motor Cortex

tFUS is an emerging neuromodulatory tool that uses pulses of low-intensity acoustic waves to stimulate deep brain structures such as the thalamus. tFUS has recently been used to probe deep brain structures in unresponsive wakefulness, pain, anxiety, and other neuropsychiatric conditions. However, tFUS is restricted mainly by use in the MR scanner environment, thus limiting session numbers by scan cost and participant comfort. Furthermore, with few human studies to date, the parameter space and mechanisms of action warrant further elucidation. Using novel focused ultrasound methods, investigators can stimulate at a minimum penetration distance of 20mm, uniquely enabling the study of the neuromodulatory effects of tFUS on cortical tissue. Specifically, investigators propose to study the effects of motor tFUS on motor-evoked potentials (MEPs) and GABA concentration. The proposed research is critical for understanding tFUS and advancing its therapeutic potential for future clinical trials.