STIMULATION AND RECORDING FROM REGENERATED PERIPHERAL-NERVES THROUGH POLYIMIDE SIEVE ELECTRODES

This paper describes the use of a new polyimide sieve electrode as a c hronic neural interface to stimulate and record signals from regenerat ed peripheral nerves. Flexible thin polyimide electrodes were placed i n silicone chambers and implanted between the severed ends of the scia tic nerve in rats. The sieve part of the interface has 281 round via h oles of 40 mu m diameter, with seven integrated recording-stimulating electrodes arranged around via holes. Axonal regeneration through the via holes was demonstrated by histological and physiological methods o ver a two to six month post-implantation period in all the rats. The r egenerated nerves were organized in fascicles corresponding to the gri d pattern of the via holes. Longitudinal sections showed myelinated fi bers, with normal appearance and well developed myelin sheath, crossin g the via holes. Stimulation of the regenerated nerve through the poly imide electrode evoked distal muscle and nerve responses similar in am plitude to those evoked by nerve stimulation with hook metal electrode s. The polyimide electrodes were useful for recording nerve action pot entials in response to electrical stimulation of the distal regenerate d nerve, and in response to functional sensory stimulation of several modalities.