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Spatiotemporal summation of perimetric stimuli in healthy observers

Montesano, G; Mulholland, PJ; Garway-Heath, DF; Evans, J; Ometto, G; Crabb, DP; (2023) Spatiotemporal summation of perimetric stimuli in healthy observers. Journal of Vision , 23 (4) , Article 2. 10.1167/jov.23.4.2. Green open access

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Abstract

Spatial summation of perimetric stimuli has been used to derive conclusions about the spatial extent of retinal-cortical convergence, mostly from the size of the critical area of summation (Ricco's area, RA) and critical number of retinal ganglion cells (RGCs). However, spatial summation is known to change dynamically with stimulus duration. Conversely, temporal summation and critical duration also vary with stimulus size. Such an important and often neglected spatiotemporal interaction has important implications for modeling perimetric sensitivity in healthy observers and for formulating hypotheses for changes measured in disease. In this work, we performed experiments on visually heathy observers confirming the interaction of stimulus size and duration in determining summation responses in photopic conditions. We then propose a simplified computational model that captures these aspects of perimetric sensitivity by modelling the total retinal input, the combined effect of stimulus size, duration, and retinal cones-to-RGC ratio. We additionally show that, in the macula, the enlargement of RA with eccentricity might not correspond to a constant critical number of RGCs, as often reported, but to a constant critical total retinal input. We finally compare our results with previous literature and show possible implications for modeling disease, especially glaucoma.

Type: Article
Title: Spatiotemporal summation of perimetric stimuli in healthy observers
Location: United States
Open access status: An open access version is available from UCL Discovery
DOI: 10.1167/jov.23.4.2
Publisher version: https://doi.org/10.1167/jov.23.4.2
Language: English
Additional information: Copyright © 2023 The Authors. This work is licensed under a Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0).
UCL classification: UCL
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > Institute of Ophthalmology
URI: https://discovery.ucl.ac.uk/id/eprint/10168552
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