Timekeeping is part of the very fabric of life, embedded in the genes and expressed in orchestrated cycles of molecules, cells and body systems. Life processes oscillate over timescales of milliseconds to years. Understanding circadian rhythms, those repeating ~24 hours, has been a grand challenge.In this talk, Martha Gillette will describe research she and her students have been conducting on the master circadian clock of the brain. They are generating answers to the following questions.

• How does a ~24-hour clockwork emerge from biological parts?
• How does the master brain clock synchronize us to the ever-changing natural world?
• How does this brain clock orchestrate timing of brain processes?

Findings have broad applications for developing: 1) environmental or drug interventions that rapidly reset the clock during transmeridian travel (jet lag) or shift work, 2) strategies for ameliorating internal desynchronization that manifests as disordered sleep, depressive mental disorders, negative affective states, and physiological decline with aging, and 3) therapeutic treatments synchronized to times of maximal effectiveness in the daily oscillation of internal state.