Kriegsfeld: What many people think is that these cycles are controlled by some sort of external cue in the environment like the rising and setting of the sun or daily temperature cycles, but there's a clock in your brain that's located in an area of the brain called the suprachiasmatic nucleus, or SCN, that controls all these cycles. If you eliminate that clock or if you have a tumor that eliminates that clock, then you will no longer have cycles in your physiology and behavior.
Narrator: Lance Kriegsfeld, a professor of psychology and neuroscience at the University of California, Berkeley is studying how the body's internal clock affects hormone cycles in the body, including ovulation, and how disruptions contribute to the fatigue and insomnia of jet lag.
Kriegsfeld: If we can get a handle on how to control the timing of these hormones, we could begin to get a handle on how to help reduce the effects of these jet lags or temporal disruptions.
Narrator: For Science Today, I'm Larissa Branin.