Seo, D. et al. Neuron 91, 529–539 (2016).

Implanted devices that record neural activity in model organisms such as rats ideally should be as small as possible, remotely powered and able to transduce information wirelessly. Seo et al. aim for all of these features by using neural dust to record from peripheral neurons in the mouse. Neural dust is a tiny recording system that consists mainly of electrodes and a piezoelectric crystal. The crystal reflects ultrasonic energy (sent from an external transducer) after neural activity picked up with the electrodes modulates the ultrasonic signal. Electrical activity can thus be inferred from the difference in emitted and received ultrasound signal. The researchers applied their technology in vivo to obtain electroneurographic and electromyographic recordings from rat sciatic nerve and skeletal muscles, respectively.