The rhythmic daily patterning of activity and rest is a fundamental feature of virtually all forms of vertebrate life, including our own, and is heavily influenced by light. Light has very different effects on day-active and night-active species, with the former responding to darkness by increasing sleep and the latter responding with a decrease. Very little is known about the brain mechanisms mediating these effects of light on rest/sleep, and essentially nothing is known about how these mechanisms differ among day-and night-active species. The research to be undertaken in this project will begin to fill this gap in our fundamental understanding of these issues suing multiple approaches. First the behavioral responses to light will be directly compared in nocturnal and diurnal rodents, then the neural mechanisms mediating those responses will be characterized. The work will determine how specific populations of cells in the brain are affected by the changes in lighting conditions that affect rest and activity, and the role that these structures play in the process will then evaluated experimentally. The project outcomes could yield fundamental new insights into processes that have a profound impact on the lives of day-active animals including humans. A better basic understanding of these issues will lead to improved strategies to help the millions of Americans with sleep problems cope with them more effectively. Strategies that could be informed by the outcomes of this project include appropriately patterned administration of light, as well as, ultimately, new, safer and more effective pharmacological treatments. The project will also engage many undergraduate and graduate students in the research enterprise in ways that will provide them an inside view of how science is done.
