Obsessions with Time in the Body and Time in the World

Remarkably, the manifestation of celestial and temporal mechanics are mirrored in the molecular biology of the cell. Even after spending decades exploring this truth, it remains remarkable that today neuroscientists can actually see cells of the body beating with a circadian (about a day) rhythm, and can watch as the clocks in our brains bow every day to the orders of the celestial world.

This lecture will show that there is a clock in the brain. This clock consists of about 20,000 neurons, and lies in the suprachiasmatic nuclei (SCN) of the hypothalamus. The time of this brain clock is driven by the cycles of light and darkness in our local environment. The brain clock lies at the top of a hierarchically organized system that controls virtually every normal and abnormal function of our body, from the timing of sleep and wake, to our ability to respond to the growth of cancer cells.

Cells in the brain clock are privileged to receive light information from sun rise and sunset allowing the interpretation of celestrial time. This information is communicated to the rest of the brain and the body by nervous and humoral signals. Time is thereby se in peripheral tissues, which themselves contain independent clocks. In summary, the body clock shop shows how time and season are represented in the space of our bodies.

Biographical Note

Prof. Rae Silver is Professor of Natural and Physical Sciences at Columbia University, New York. She is an expert in medical and biological aspects of the internal body clock.