Efficacy of Aperiodic Electrical Stimulation in Retina to Enhance Visual Cortical Responses.

Visual prosthesis exhibits the capabilities in restoring partial vision function for patients afflicted with retinal degenerative diseases. Natural stimuli consist of aperiodic events spanning over a short temporal duration. However, periodic stimulation is generally used in most studies. In this study, in vivo experiments on both retinal degenerated S334ter-line-3 (F1) rats and Sprague Dawley (SD) rats were performed to explore the impact of aperiodic retinal stimulation on the electrically evoked response in the primary visual cortex (V1) in comparison to periodic stimulation. It was noticed that the periodic retinal stimulation elicited a pronouncedly lower spike rate compared with the aperiodic pattern at frequencies of 10 and 20 Hz in SD rats. F1 rats showed similar but weaker trend. The time precision of responses was also explored. The aperiodic stimulation with 50% noise increased the temporal precision of the cortical response in comparison to periodic stimulation at 20 Hz in both SD and F1 rats. These findings implied a prospective way to improve the performance of the retinal implants from the aspect of temporal precision by using aperiodic stimulation.