Melanopsin photoreception and its interaction with cone and rod signals in the human visual pathways

This thesis evaluated interactions between different photoreceptor types (melanopsin cells, cones, and rods) in the human visual system. Methods for generating photoreceptor-specific lights were optimised to mitigate the effects of individual differences in vision. Implementing these methods, it was shown that melanopsin signals can suppress or enhance cone- and rod-mediated vision depending on viewing conditions. Electrophysiological recordings conducted using photoreceptor-specific lights revealed that cone photoreceptor signals suppressed by melanopsin in the outer retina are amplified in the post-receptoral pathways. The thesis provided new insights into how human visual sensitivity is set by the combined activity of all three photoreceptor types.