The spatial distribution of ERGs reflecting luminance and L-/M-cone-opponent signals

Author(s)

Vidal, Kallene Summer ^{[1, 2]} ; Aher, Avinash J. ^[1] ; Ventura, Dora Fix ^[2] ; Kremers, Jan ^{[3, 1, 4]}

Affiliation

^[1] Univ Hosp Erlangen, Dept Ophthalmol, Schwabachanlage 6, D-91054 Erlangen - Germany

^[2] Univ Sao Paulo, Lab Vis, Inst Psychol, Sao Paulo - Brazil

^[3] Univ Bradford, Sch Optometry & Vis Sci, Bradford, W Yorkshire - England

^[4] FAU Erlangen Nurnberg, Deparment Anat 2, Erlangen - Germany

• Document type: Journal article
• Source: DOCUMENTA OPHTHALMOLOGICA; v. 142, n. 3 JAN 2021.
• Web of Science Citations: 1

Abstract

Purpose To study the spatial retinal distribution of electroretinographic (ERG) responses that reflect signals in the L-/M-cone-opponent and luminance post-receptoral pathways. Methods ERG recordings to heterochromatic stimuli (sinusoidal counter-phase modulation of red and green LED light sources) were performed, while varying fractions of red and green modulation. Two temporal frequencies of the stimuli were employed: 12 Hz to record ERGs that reflect L-/M-cone-opponent signal and 36 Hz for recording ERG signals sensitive to stimulus luminance. Stimuli were about 20 degrees in diameter and projected on various retinal locations: the fovea and four eccentricities (10 degrees, 19 degrees, 28 degrees and 35 degrees), each presented nasally, temporally, inferiorly and superiorly from the fovea. Results The 36 Hz stimuli elicited responses that strongly varied with red fraction and were minimal at iso-luminance. Moreover, response phases changed abruptly at the minimum by 180 degrees. In contrast, the responses to the 12 Hz stimuli had amplitudes and phases that changed more gradually with red fraction. The 36 Hz response amplitudes were maximal close to the fovea and sharply decreased with increasing distance from the fovea. The responses to 12 Hz stimuli were more broadly distributed across the retina. Conclusions In the present study, it was found that retinal eccentricity and direction from the fovea have distinct effects on ERGs reflecting different post-receptoral mechanisms. The results are in accord with previous findings that ERGs to 12 Hz stimuli are predominantly determined by the red-green chromatic content of the stimuli, thus reflecting activation in the L-/M-cone-opponent pathway, while responses to 36 Hz stimuli manifest post-receptoral luminance-dependent activation. We found that the response in the cone-opponent pathway is broadly comparable across the retina; in comparison, response amplitude of the luminance pathway strongly depends on retinal stimulus position. (AU)

• FAPESP's process: 14/26818-2 - Development and implementation of visual evaluation methods: clinical applications and animal models
• Grantee: Dora Selma Fix Ventura
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 17/01367-6 - Functional images of the retina: using electroretinography to investigate the pathophysiology of glaucoma
• Grantee: KALLENE SUMMER MOREIRA VIDAL
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor