title: Probing the functional impact of sub-retinal prosthesis.
abstract: Retinal prostheses are promising tools for recovering visual functions in blind patients but, unfortunately, with still poor gains in visual acuity. Improving their resolution is thus a key challenge that warrants understanding its origin through appropriate animal models. Here, we provide a systematic comparison between visual and prosthetic activations of the rat primary visual cortex (V1). We established a precise V1 mapping as a functional benchmark to demonstrate that sub-retinal implants activate V1 at the appropriate position, scalable to a wide range of visual luminance, but with an aspect-ratio and an extent much larger than expected. Such distorted activation profile can be accounted for by the existence of two sources of diffusion, passive diffusion and activation of ganglion cells' axons en passant. Reverse-engineered electrical pulses based on impedance spectroscopy is the only solution we tested that decreases the extent and aspect-ratio, providing a promising solution for clinical applications.
authors.affiliation: Institut de Neurosciences de la Timone, CNRS, Aix-Marseille Université, Marseille, France.
authors.forename: Sébastien
authors.identifier: 0000-0003-2366-6430
authors.initials: S
authors.lastname: Roux
authors.affiliation: Institut de Neurosciences de la Timone, CNRS, Aix-Marseille Université, Marseille, France.|Ophthalmology Department, Aix Marseille Université, Hôpital Nord,Hôpital de la Timone, Marseille, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Matonti
authors.affiliation: CEA-LETI, Grenoble, France.|Université Grenoble Alpes, Grenoble, France.
authors.forename: Florent
authors.initials: F
authors.lastname: Dupont
authors.affiliation: Institut de Neurosciences de la Timone, CNRS, Aix-Marseille Université, Marseille, France.|Ophthalmology Department, Aix Marseille Université, Hôpital Nord,Hôpital de la Timone, Marseille, France.
authors.forename: Louis
authors.initials: L
authors.lastname: Hoffart
authors.affiliation: Institut de Neurosciences de la Timone, CNRS, Aix-Marseille Université, Marseille, France.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Takerkart
authors.affiliation: Inserm, UMRS-986, Institut de la vision, Paris, France.
authors.forename: Serge
authors.initials: S
authors.lastname: Picaud
authors.affiliation: CEA-LETI, Grenoble, France.|Université Grenoble Alpes, Grenoble, France.
authors.forename: Pascale
authors.initials: P
authors.lastname: Pham
authors.affiliation: Institut de Neurosciences de la Timone, CNRS, Aix-Marseille Université, Marseille, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Chavane
mesh_terms: D000818:Animals; D023421:Models, Animal; D051381:Rats; D014793:Visual Cortex / Q000502:physiology*; D057488:Visual Prosthesis
keywords: artificial visual acuity; human biology; impedance spectroscopy; medicine; neuroscience; optical imaging; primary visual cortex; rat; retinal implants