Cortical response after chronic electrical stimulation of canine retina

Electrical stimulation of the canine retina (in normal and RCD1) is carried out. An electronic retinal prosthetic chip is implanted which contain an implantable stimulator and 16 platinum electrodes disks of 460μ diameter placed on the retina. Three dogs were chronically stimulated at 0.05 mC/cm² and 0.1 mC/cm² for 120 days (8-10 hours per day). Bright flash electroretinograms (ERG´s) were recorded on the three dogs and found no recordable ERG from a blind dog. After completion of the stimulation protocol cortical subdural electrodes were implanted to record the cortical response for the electrical stimulation of the retina. The aim of this study is to evaluate the electrical evoked cortical responses in normal and blind dogs implanted with subdural electrodes.