Fully implantable neural recording and stimulation interfaces: Peripheral nerve interface applications.

Background: Peripheral nerve interfacing has many applications ranging from investigation of neural signals to therapeutic intervention for varied diseases. This need has driven technological advancements in the field of electrode arrays and wireless systems for in-vivo electrophysiological experiments. Hence we present our fully implantable, programmable miniaturized wireless stimulation and recording devices.

New Method: The method consists of technological advancements enabling implantable wireless recording up to 128 channels with a sampling rate of 50Khz and stimulation up to ±4 mA from 15 independent channels. The novelty of the technique consists of induction charging cages which enables freely moving small animals to undergo continuous electrophysiological and behavioral studies without any impediments. The biocompatible hermetic packaging technology for implantable capsules ensures stability for long-term chronic studies.

Results: Electromyographs wirelessly recorded from leg muscles of a macaque and a rat using implantable technology are presented during different behavioral task studies. The device's simultaneous stimulation and recording capabilities are reported when interfaced with the vagus and pelvic nerves.

Comparison With Existing Method(s): The wireless interfacing technology has a large number of recording and stimulating channels without compromising on the signal quality due to sampling rates or stimulating current output capabilities. The induction charging technology along with transceiver and software interface allows experiments on multiple animals to be carried out simultaneously.

Conclusions: This customizable technology using wireless power transmission, reduced battery size, and miniaturized electronics has paved way for a robust, fully implantable, hermetic neural interface system enabling the study of bioelectronic medical therapies.