Fig. 6: Impedance of the electrodes in treated rats increased steadily in vivo, but this rise was unrelated to the delivery of treatment and reduced upon tissue removal in recovered implants.

a Impedance magnitude and b phase for active electrodes used for stimulation are shown over 12 weeks, indicated by the color scale, with the dashed red line representing the open circuit level. See Supplementary Fig. 9 for reserve electrodes. c Impedance at 1 kHz illustrates a steady increase throughout the 12 weeks for both stimulation and reserve electrodes, remaining below the open circuit level expected for a broken channel or electrode. d, e In vivo and in vitro measurements from two explants that were removed intact at 4 and 3 weeks, respectively. Both explants showed impedance approaching pre-implementation levels after mechanical removal of encapsulating tissue.