Design of a minimally invasive low-frequency microtransducer for ultrasonic neuromodulation

Abstract

Studies with low intensity focused ultrasound (LIFU) and other related techniques have recently demonstrated the potential for ultrasound to reversibly modulate neural circuits in a number of different in vivo models. However, accurate acoustic targeting can be complicated by the attenuation and distortion of the acoustic beam during transcranial passage through the cranium. This can potentially complicate basic studies of the effects of targeted ultrasonic neurostimulation. An alternative intervention strategy is to develop ultrasonic neurostimulator probes small enough to be minimally-invasively implanted directly adjacent to target neural structures. Two different configurations of PZT-based low frequency microtransducers were designed, fabricated, and evaluated for such a strategy. Acoustic testing demonstrated evenly collimated acoustic radiation profiles, and a pilot study in a small animal model demonstrated the overall feasibility of this approach.