Role of ipRGCs and wide-field amacrine cells in light adaptation
Another branch of our research program focuses on dissecting retinal circuits encoding intensity vs. contrast and their roles in light adaptation. While ipRGCs transmit intensity-encoding signals, all other RGCs are optimized for the transmission of contrast-encoding signals and support detection and recognition of objects, color and motion. Though contrast and intensity signals are carried through these distinct sets of retinal outputs, they also appear to interact in the context of light adaptation. Light adaptation allows the retina to encode contrast over a huge range of light intensities, from starlight to midday sunlight. To date, the role of ipRGC networks in light adaptation as well as the route by which they modulate the responses of retinal neurons has only been implied, but never confirmed. We will explore how intensity signals propagate in the retina, affect the physiology of inner retinal neurons, and possibly mediate light adaptation. This work will contribute not only to our understanding of light adaptation, which is an important and intensive field of research, but also to our understanding of neural adaptation in general, in other sensory systems.