Melanopsin-mediated amplification of cone signals in the human visual cortex
Cite this dataset
Adhikari, Prakash; Uprety, Samir; Feigl, Beatrix; Zele, Andrew (2024). Melanopsin-mediated amplification of cone signals in the human visual cortex [Dataset]. Dryad. https://doi.org/10.5061/dryad.12jm63z62
Abstract
The ambient daylight variation is coded by melanopsin photoreceptors and their luxotonic activity increases towards midday when colour temperatures are cooler, and irradiances are higher. Although melanopsin and cone photoresponses can be mediated via separate pathways, the connectivity of melanopsin cells across all levels of the retina enables them to modify cone signals. The downstream effects of melanopsin-cone interactions on human vision are however, incompletely understood. Here, we determined how the change in daytime melanopsin activation affects the human cone pathway signals in the visual cortex. A 5-primary silent-substitution method was developed to evaluate the dependence of cone-mediated signals on melanopsin activation by spectrally tuning the lights and stabilising the rhodopsin activation under a constant cone photometric luminance. The retinal (white noise electroretinogram, wnERG) and cortical responses (visual evoked potential, wnVEP) were simultaneously recorded with the photoreceptor-directed lights in 10 observers. By increasing the melanopsin activation, a reverse response pattern was observed with cone signals being supressed in the retina by 27% (p=0.03) and subsequently amplified by 16% (p=0.01) as they reach the cortex. We infer that melanopsin activity can amplify cone signals at sites distal to retinal bipolar cells to cause a decrease in the psychophysical Weber fraction for cone vision.
README: Melanopsin-mediated amplification of cone signals in the human visual cortex
https://doi.org/10.5061/dryad.12jm63z62
The data are electrophysiological recordings of the human electroretinogram (ERG) and visual evoked potential (VEP) measured under conditions of 5-primary silent substitution.
Description of the data and file structure
Sheet 1: Overview
Sheet 2: Fig. 2 Data:
Column C to G: Irradiance output (Watts.cm-2) of the 5-primary lights (B, C, G, A, R) as a function of wavelength (nm) in the low melanopsin adaptation background (ilow).
Column I to M: Irradiance output (Watts.cm-2) of the 5-primary lights as a function of wavelength (nm) in the high melanopsin adaptation background (ihigh).
Column P to S: Cone-directed wnERG and wnVEP responses (µV) as a function of time (ms) measured under low (ilow) or high (ihigh) melanopsin excitation.
Sheet 3: Fig. 3 Data:
Mean and SEM of the cone-directed wnERG and wnVEP amplitudes (µV) and implicit times (ms) measured under ilow or ihigh adaptation.
Sheet 4: Fig. 4 Data:
Cone-directed wnVEP to wnERG amplitude ratio with ihigh to ilow adaptation.
Sheet 5: Fig. 5 Data:
Cone-directed wnERG and wnVEP amplitudes (µV) as a function of recording (s) time under ilow or ihigh melanopsin adaptation.
Sheet 6: Fig. 6 Data:
Column B to I: Frequency (proportion) of the cone-directed wnERG N1 amplitude (µV) under ilow or ihigh melanopsin adaptation and the best-fitting hyperbolic secant model.
Column K to R: Frequency (proportion) of the cone-directed wnERG N1P1 amplitude under ilow or ihigh adaptation and the best-fitting hyperbolic secant model.
Column T to AA: Frequency (proportion) of the cone-directed wnVEP N2P2 amplitude under ilow or ihigh adaptation and the best-fitting hyperbolic secant model.
Column AC to AJ: Frequency (proportion) of the cone-directed wnERG N1 implicit time (ms) under ilow or ihigh adaptation and the best-fitting hyperbolic secant model.
Column AL to AS: Frequency (proportion) of the cone-directed wnERG P1 implicit time under ilow or ihigh adaptation and the best-fitting hyperbolic secant model.
Column AU to BB: Frequency (proportion) of the cone-directed wnVEP P2 implicit time under ilow or ihigh adaptation and the best-fitting hyperbolic secant model.
Column BD to BH: Intra-observer coefficient of variation (CoV, %) of the cone-directed wnERG N1P1 amplitudes and wnVEP N2P2 amplitudes under ilow or ihigh melanopsin adaptation.
Funding
Australian Research Council, Award: ARC-FT180100458