DOI: 10.5061/dryad.12jm63z62
title: Melanopsin-mediated amplification of cone signals in the human visual cortex

description: 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.
description: # Melanopsin-mediated amplification of cone signals in the human visual
 cortex
 [https://doi.org/10.5061/dryad.12jm63z62](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.