The mechanism of jet lag
Schematic representation of the dissociation and slow resynchronization of endogenous oscillators within the rat SCN after an LD cycle shift.
A rapid shift of light: dark cycle dissociates the suprachiasmatic nucleus (SCN), the mammalian circadian center. Light-responsive clocks in the ventrolateral region of the SCN shifts rapidly while the light-unresponsive ones in the dorsomedial region shift very slowly. During the desynchrony, the locomotor activity of animals shows increased nighttime rest, showing the jet lag of animals. It takes 5 to 10 days for rats to obtain steady circadian rhythm of locomotor activity and resynchronization of the SCN. OC, Optic chiasm; III, the third ventricle.