Clockwork Blue – The clock in our head

Prof. Dr. Jörg Stehle, Dr. Senckenbergische Anatomie, Universitätsklinikum Frankfurt

Life on earth is decisively determined by the recurring 24-hour rhythm of brightness and darkness. A decisive evolutionary advantage was therefore the forecasting of repeating events with a 24-hour cycle duration. In humans, too, an internal clock has therefore developed that ticks with amazing precision in a circadian rhythm. However, this inner clock has to be readjusted a little every day in order to correspond to the physically exact 24-hour day-night change, which is usually caused by light. Chronobiology deals with phenomena concerning the mechanism and function of the internal clock and its influence, but also with the effects of disturbances. The circadian clock is located in a small core area in our diencephalon and is based on a rather simple molecular control loop. Adjustments, but also disturbances of this clockwork in our brain influence our daily life and lead to partly considerable, also health-related consequences. Understanding the functioning of chronobiological processes in our body reveals their fundamental importance for our daily life and recognises possibilities, but also dangers, which arise from influencing the circadian clock.