In humans, changes in day length, shift-work or trans-meridian travel lead to deficits in mood and cognitive functions. Previously, these deficits were thought to arise exclusively from sleep deprivation and/or disruptions in circadian rhythms. Work from Dr. Samer Hattar’s laboratory has recently shown that light can directly affect mood and learning, even in the context of normal sleep and functional circadian activity. The goal of our project is to determine the retinal and brain circuits that underlie the effects of an aberrant light schedule on mood and cognitive functions, by employing a combination of anatomical, functional, and behavioral approaches. We will evaluate the effects of social and sensory stimulations as possible therapies to prevent the mood and learning deficits induced in mice exposed to aberrant light schedules. Results obtained from this work will uncover the connectivity and functions of new retinal-brain circuits that are required for regulating mood and cognitive functions, independent of image formation. Understanding the interaction between light and complex behaviors could lead to more effective treatments for mood disorders, and more generally, better designs for lighting environments that could enhance learning abilities.