Safety, Parameterization, and Mechanism of Transcranial Focused Ultrasound

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.

Inclusion criteria

• Male or female
• Age 18-55
• Endorse good health with no history of mental or physical illness or implanted metal
• English as a primary language
• Capacity to consent
• Negative urine pregnancy test if a female of childbearing potential
• Willingness to adhere to the tFUS and MRI study schedule

Exclusion criteria

• Any psychotropic medication is taken within 5 half-lives of procedure time
• Any head trauma resulting in loss of consciousness
• Personal or family history of neurological illness or injury
• Alcohol or substance abuse or dependence (other than tobacco) in the past week
• Diagnosis or current treatment (pharmacological or otherwise) of any psychiatric condition
• Pregnancy
• Personal or family history of seizures or epilepsy
• Claustrophobia or inability to stay still in the MR scanner environment
• Any metal in the body
• Other contraindications to electrical or electromagnetic stimulation
• Hair in dreadlocks, braids, or weave
• Diagnosis of COVID-19 in the past 14 days
• Inability to adhere to the treatment schedule.