Thresholds for activation of rabbit retinal ganglion cells with an ultrafine, extracellular microelectrode.

Purpose: To determine electrical thresholds required for extracellular activation of retinal ganglion cells as part of a project to develop an epiretinal prosthesis.

Methods: Retinal ganglion cells were recorded extracellularly in retinas isolated from adult New Zealand White rabbits. Electrical current pulses of 100- micro s duration were delivered to the inner surface of the retina from a 5- micro m long electrode.