Origins and Transformations of Signals for Circadian Regulation

PROJECT SUMMARY The earth’s rotation drives profound changes in our environment. Practically every tissue of the body is synchronized to this rhythm by an internal timekeeping mechanism, the circadian clock. Desynchronization impairs mood, cognition, and physiology—commonly experienced in shift work and jet lag. Proper exposure to

light realigns the clock with the solar day and can reverse these impairments. We have developed a new method to access the pathway that joins the eye with the master clock in the brain. We propose to define how information is generated within the retina and subsequently transformed as it enters clock circuitry. We expect

to provide knowledge of how physiology is tuned to environmental cycles, and of the division of labor between retina and brain.