MELANOPSIN CONTRIBUTION TO PATTERNS DISCIRMINATION IN DIURNAL AND NOCTURNAL RODENTS

Descrizione del progetto

Migliore comprensione del sistema visivo attraverso la melanopsina

La melanopsina è un tipo di fotopigmento appartenente a una famiglia più ampia di proteine retiniche sensibili alla luce. Dati recenti provenienti da studi sui topi mostrano che la melanopsina può fornire al cervello informazioni sui modelli spaziali durante il giorno, integrando così l’attività dei coni nella rappresentazione di ampiezze maggiori e pattern più grossolani in condizioni di luminosità. Il progetto MEL-ROD, finanziato dall’UE, si propone di determinare in che modo il ruolo della melanopsina a sostegno della visione differisce tra topi notturni e un muride diurno con una forte visione diurna basata sui coni. Il progetto prevede di utilizzare una tecnologia all’avanguardia che permetterà, per la prima volta, di generare pattern visibili solo alla melanopsina.

Obiettivo

Three types of retinal photoreceptors are responsible for light detection: rods, cones and intrinsically photosensitive retinal ganglion cells (ipRGCs) containing melanopsin. Until recently, it was universally assumed that daytime vision originates with cones, dim light vision with rods, leaving ipRGCs to drive sub-conscious reflex responses to changes in ambient light (e.g. circadian photoentraiment). However, very recent data from mice has revolutionized vision science by showing that melanopsin can also provide the brain with information about the spatial patterns during the day, complementing the activity of cones in the representation of larger amplitude and coarser patterns in brightness. The proposed project is aimed to determine how melanopsin and cones work together to create images in nocturnal mice and in a diurnal murid (Rhabdomys) with strong cone-based daytime vision, respectively. We will take advantage of technological edge in multi-primary visual display (mVDU) design that allows, for the first time, patterns visible only to melanopsin to be generated. We will apply the mVDU technology to in vivo multi-unit electrophysiological recordings from the visual thalamus (the dorsal lateral geniculate nucleus) and behavioural experiments on melanopsin sufficient and deficient mice created by optogenetical manipulation of ipRGCs. We hypothesize that there will be significant differences in the melanopsin contribution to pattern discrimination between chosen night and day active animals due to the difference in their retinal structure (rod-cone ratio). We believe that the proposed research will contribute to better understanding of the visual system and lead to a step change in performance of image capture and display technologies by adjusting their design to take account of melanopsin. The applicant will benefit from the project with new skills, knowledge and the experience to launch her own research group in the future.