Comparison Of Cell-Type Specific Optogenetic Cortical Stimulation Targeting Distinct Neural Populations For The Restoration Of Vision

Stimulation of the visual cortex is a promising method for the restoration of vision, covering a broad range of patients with visual impairments. Optogenetic stimulation has the potential to advance visual restoration. To design better optogenetic implants, an appropriate combination of specific cell types and optogenetic proteins should be identified. Here, we developed a photo-stimulator system and characterized two combinations in the primary visual cortex: targeting excitatory neurons with the red-light-sensitive opto-stimulator chrimsonR and targeting parvalbumin-positive inhibitory neurons with the red-light-sensitive opto-silencer eNpHR-3.0. A custom-developed system consisting of a mini-LED device emitting redshift light and two convex lenses was installed above the V1 for light focus. We recorded and compared the electrophysiological responses to both visual stimuli and photostimulation. The optogenetic stimulations resulted in a slightly larger number of silence-evoked neurons than excitation-evoked neurons, with a similar number of neurons that responded to visual stimuli.