About: Dual circadian oscillator model

In the field of chronobiology (the study of circadian rhythms), the dual circadian oscillator model refers to a model of entrainment (where rhythmic events in an organism match oscillation in the environment) initially proposed by Colin Pittendrigh and Serge Daan. The dual oscillator model suggests the presence of two coupled circadian oscillators: E (evening) and M (morning). The E oscillator is responsible for entraining the organism’s evening activity (activity offset) to dusk cues when the daylight fades, while the M oscillator is responsible for entraining the organism’s morning activity (activity onset) to dawn cues, when daylight increases. The E and M oscillators operate in an antiphase relationship. As the timing of the sun's position fluctuates over the course of the year, the os