Circadian Rhythms

We've all been there: staring at the ceiling at 2:43 a.m., unable to fall asleep while the world slumbers around us. How do our internal clocks stay synced to our environment? What exactly do they control? Might future research provide relief for late-night workers or the jet-lagged when the natural rhythms of the body are disturbed? Erik Herzog, professor of biology at Washington University in St. Louis, explains how the brain's "master clock" works and how genetic mutations and natural toxins can influence our daily biological rhythms.