Abstract: Improved acoustic neurostimulation is provided by having two or more acoustic transducers generate an acoustic interference pattern in a region of a patient being treated. The apparatus has at least two operating modes it can switch between. A first operating mode has the transducers driven at the same frequency. A second operating mode has the transducers driven at different frequencies. Full control of the acoustic transducers allows the acoustic interference pattern to be varied electronically at will.

Abstract: Focused ultrasound is a promising technology for neural stimulation that is non-invasive, and capable of passing through the skull. Here we use the isolated retina to characterize the effect of ultrasound on an intact neural circuit and compared these effects to those of visual stimulation of the same retinal ganglion cells. Ultrasound stimuli evoked precise, stable responses that looked qualitatively similar to strong visual responses but with shorter latency. We found that ultrasonic stimulation activates cells presynaptic to ganglion cells, which may include photoreceptors and interneurons. Ultrasonic stimulation is an effective and spatial-temporally precise method to activate the retina. Ultrasonic stimulation may have diagnostic potential to probe remaining retinal function in cases of photoreceptor degeneration, and therapeutic potential for use in a retinal prosthesis. In addition, ultrasound promises to be a useful tool to understand the dynamic activity in the interneuron population of the retina.