Probing the functional impact of sub- retinal prosthesis

Sébastien Roux (1) , Frédéric Matonti (2, 1) , Florent Dupont (3) , Louis Hoffart (2, 1) , Sylvain Takerkart (1) , Serge Picaud (4) , Pascale Pham (3) , Frédéric Chavane (1)

1 INT - Institut de Neurosciences de la Timone
2 Ophtalmologie [Hôpital de la Timone - APMH]
3 CEA-LETI - Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information
4 Institut de la Vision

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.

Domaines: Neurobiologie; Ingénierie biomédicale

Sébastien Roux, Frédéric Matonti, Florent Dupont, Louis Hoffart, Sylvain Takerkart, et al.. Probing the functional impact of sub- retinal prosthesis. eLife, 2016, 5, pp.e12687. ⟨10.7554/eLife.12687⟩. ⟨hal-01460757⟩