Distributed implantable microchips as wireless networks for neural sensing and stimulation

We examine ongoing research for implantable sensors and stimulators for future brain-computer applications and give a review on the concept where grain-of-sand size silicon microchips form the individual nodes in a multichannel wireless implant. In such an approach, each chip can perform the function of a stand-alone independent sensor if equipped with active microelectronic circuits designed to detect or stimulate target populations of neurons and capability for wireless communication. Delivering power to individual as well as spatially distributed ensembles of microchips requires a method for efficient transcutaneous/transcranial wireless energy transfer approach. Here we offer examples from authors' experience and comparisons to contemporary approaches as well as the challenges ahead in developing clinically viable wireless cortical chip-in-the-brain interfaces.