Transcranial ultrasound stimulation of the human motor cortex

Summary It has been 40 years since the report of long-term synaptic plasticity on the rodent brain. Transcranial ultrasound stimulation (TUS) shows advantages in spatial resolution and penetration depth when compared to electrical or magnetic stimulation. The repetitive TUS (rTUS) can induce cortical excitability alteration on animals and persistent after-effects were observed. However, the effects of rTUS on synaptic plasticity in humans remain unelucidated. In the current study, we applied a 15-min rTUS protocol to stimulate left-M1 in 24 male healthy participants. The single-pulsed TMS evoked MEP and Stop-signal task was applied to measure the rTUS after-effects. Here, we report that conditioning the human motor cortex using rTUS may produce long-lasting and statistically significant effects on motor cortex excitability as well as motor behavior, without harmful side effects observed. These findings suggest a considerable potential of rTUS in cortical plasticity modulation and clinical intervention for impulsivity-related disorders.