Ultrasonic modulation of neural circuit activity

•Low-intensity ultrasound can non-invasively modulate neuronal activity.•Ultrasound can modulate brain circuits at high spatial resolutions.•Neuromodulation with ultrasound can provide a means of functional brain mapping.•Acoustic forces can act on channels to modulate neuronal activity.•Ultrasound is poised for integration in next generation neural interfaces. Ultrasound (US) is recognized for its use in medical imaging as a diagnostic tool. As an acoustic energy source, US has become increasingly appreciated over the past decade for its ability to non-invasively modulate cellular activity including neuronal activity. Data obtained from a host of experimental models has shown that low-intensity US can reversibly modulate the physiological activity of neurons in peripheral nerves, spinal cord, and intact brain circuits. Experimental evidence indicates that acoustic pressures exerted by US act, in part, on mechanosensitive ion channels to modulate activity. While the precise mechanisms of action enabling US to both stimulate and suppress neuronal activity remain to be clarified, there are several advantages conferred by the physics of US that make it an appealing option for neuromodulation. For example, it can be focused with millimeter spatial resolutions through skull bone to deep-brain regions. By increasing our engineering capability to leverage such physical advantages while growing our understanding of how US affects neuronal function, the development of a new generation of non-invasive neurotechnology can be developed using ultrasonic methods.