Fig. 4

Signals from both cone types and melanopsin combine in an additive manner to drive pupil constriction. a Representative images of mouse consensual pupil responses evoked by stimuli modulating just L- and S-opsin (in unison or antiphase) or all photoreceptors at 75% contrast. b Mean ± SEM percent change in pupil diameter across 10 mice for cone-isolating and all photoreceptor stimuli applied as square-wave modulations at two different polarities (two to four trials/mouse). Mean pupil size between ‘bright’ and ‘dim’ stimulus phases were compared by paired t tests. c Mean ± SEM change in pupil diameter between ‘bright’ and ‘dim’ stimulus phases (averaged across both stimulus polarities and normalised according to eye size) from animals contributing to panel b. Data were analysed by one-way RM ANOVA with Holm-Sidak’s multiple comparisons test. Shaded area represents mean ± SEM change in pupil size predicted from a linear sum of responses to L and S-opsin-isolating stimuli. d Mean ± SEM difference in pupil diameter between ‘bright’ and ‘dim’ stimulus phases (processed as in c) at various timepoints following the stimulus transition. Data were analysed by two-way RM ANOVA with Sidak’s post-test. For b–d, ***, **, * and n.s. indicate P < 0.001, P < 0.01, P < 0.05 and P > 0.05 respectively