A study conducted by University of California, Irvine, reveals the inner mechanisms of jet lag with the help of first real-time imaging of intact circadian neural networks, courtesy of a fruit fly's 'brain in a jar'.
Researchers used imaging technology to make movies of fruit fly brains kept alive for 6-days in a petri dish. It captured the activity of individual circadian clocks at single-cell resolution with an extremely sensitive low-light camera. This showed how the circadian clock circuit is 'reset' by light.
The scientists found that desynchronization of circadian neurons is a key feature of light-induced jet lag. They suggest that treatments accelerating this desynchronization before travel may speed recovery afterward. Todd C. Holmes said, "Remarkably, our work indicates that the way you feel while jet-lagged exactly reflects what your nervous system is experiencing- a profound loss of synchrony."
Holmes explained that a single light pulse cues the biological clock of the fruit fly brain to shift two hours ahead of its original schedule through a process the researchers call 'phase retuning', which is characterized by a circadian circuit-wide pattern of brief desynchrony followed by the gradual emergence of a new state of network synchrony. The scientists propose that temporarily weakening synchronization among neurons governed by circadian patterns allows for more rapid adaptation, an estimated 2-days, by enabling phase retuning to a new time zone's cues.
The study appears online in Current Biology