Fig. 1
From: Regulation of mouse exploratory behaviour by irradiance and cone-opponent signals
Irradiance-dependent light avoidance requires melanopsin and cone photoreception. A Schematic of the apparatus for assessing light:dark preference, comprising two interconnected and independently illuminated chambers. B Spectral composition of initial test stimuli, which recreated a wildtype mouse’s experience of natural daylight over a 2-order of magnitude range. C Mean ± SEM preference index ([TBright − TDim]/[TBright + TDim]) for Opn1mwR mice (n = 6) given a choice between the brightest vs dimmest test stimuli, double plotted as a function of time of testing (stimuli randomised across left and right sides of the chamber within and between animals). Data analysed by comparison of sinusoidal fit vs. null hypothesis of zero slopes first order polynomial fit (F-test—F1,34 = 4.43; P = 0.043). D–F Mean ± SEM preference index (testing at ZT 4.5–7.5) for Opn1mwR (D; n = 16), Opn1mwR; Opn4−/− (E; n = 11) and Cnga3−/− mice (F, n = 12), when comparing varying ‘bright’ irradiance against the dimmest test stimulus. Data analysed by one-way RM ANOVA (D: F2.852, 42.78 = 3.11, P = 0.039; E: F2.651, 26.51 = 1.08, P = 0.37; F: F2.262, 24.89 = 0.109, P = 0.92) with one-sample t-tests vs. a hull hypothesis of 0 preference, as appropriate. Shaded region in E and F represents mean ± SEM ‘bright’ preference across tested irradiances, with one sample t-tests vs. a hull hypothesis of 0 preference. * and ** represent P < 0.05 and P < 0.01, respectively