Separated interface nerve electrode prevents direct current induced nerve damage

Abstract

Direct current, DC, can be used to quickly and reversibly block activity in excitable tissue, or to quickly and reversibly increase or decrease the natural excitability of a neuronal population. However, the practical use of DC to control neuronal activity has been extremely limited due to the rapid tissue damage caused by its use. We show that a separated interface nerve electrode, SINE, is a much safer method to deliver DC to excitable tissue and may be valuable as a laboratory research tool or potentially for clinical treatment of disease.

Figure 1

Experimental setup. Three electrodes were placed on the sciatic nerve: a proximal stimulation electrode, a DC electrode and a distal stimulation electrode. DC was delivered using a traditional platinum cuff-style electrode in one leg, and using a SINE in the other. Acute nerve health was monitored by assessing the ability of the nerve to conduct impulses through the region of the DC electrode (comparing proximally to distally elicited gastrocnemius muscle force).

Figure 2

Experimental results showing that a SINE allows for safe delivery of DC to nerve. a) Typical results comparing DC delivery using a traditional platinum cuff electrode and a SINE. Abscissa is experiment time, and ordinate is proximally elicited muscle force normalized to distally elicited muscle force. Long-term (2–4 hour) recovery for the platinum electrode experiments is overlaid on the plot. (b-c) Data suggesting that DC-induced suppression using the SINE is a reversible phenomenon. b) The amount of DC required to induce prolonged suppression decreases asymptotically with cumulative DC, and rebounds after a 30 minute rest period. c) The time for recovery of conduction after DC-induced prolonged suppression increases asymptotically with cumulative DC delivery and rebounds after a 30 minute rest period.