Mark is fascinated by the physiology of sleep and circadian rhythms. Circadian rhythms are environmentally influenced and endogenously maintained daily body cycles that regulate sleeping and feeding patterns. The primary goal of his current project is to describe the connections between neurons in the mammalian master circadian pacemaker (suprachiasmatic nucleus, or SCN). The project is a collaboration between Professor Jeff Lichtman's Lab at Harvard and Professor Joseph Takahashi's Lab at the University of Texas Southwestern Medical Center. The results from this project will help to elucidate the mechanism by which circadian rhythms are produced and maintained in the mammalian brain.