Neurostimulation plays a critical role in the understanding of neural circuits and treating disease. Brain stimulation therapies now treat Parkinson’s disease, depression, dystonia, and epilepsy and hold promise for Alzheimer’s, anxiety, schizophrenia, and stroke. Neurostimulation methods that generate electrical currents, such as transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS), have strong effects on neural activity. Yet a fundamental barrier exists to noninvasive stimulation of structures deep in the brain in that electromagnetic waves cannot be focused at such a depth through neural tissue. Consequently, TMS and tDCS can only reach shallow brain structures or larger target volumes. As an alternative approach, ultrasonic neurostimulation is a promising technology that can reach deep into the brain, but current in vivo results in humans have shown effects that are much weaker than those from TMS.
This proposal aims to develop a new modality of noninvasive neural stimulation, sonomagnetic stimulation (SMS), that can generate an electrical current focused in a small volume deep in neural tissue, a goal not possible with any existing method of neurostimulation. Our proposed method combines ultrasonic and magnetic field interactions to enable remote neural activation. If successful, this approach will introduce a fundamentally new tool for the basic study of neural function and treatment of neural disease.