Fruit fly 'brain in a jar' helps discover biology of jet lag

The first real-time imaging of intact circadian neural networks, courtesy of a fruit fly's "brain in a jar," has revealed the inner mechanisms of jet lag.

To do this, UC Irvine researchers used imaging technology to make movies of fruit fly brains kept alive for six days in a petri dish. They captured the activity of individual circadian clocks at single-cell resolution with an extremely sensitive low-light camera in order to determine 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 and suggest that treatments accelerating this desynchronization before travel may speed recovery afterward.

Todd C. Holmes said that remarkably, their work indicates that the way you feel while jet-lagged exactly reflects what your nervous system is experiencing: a profound loss of synchrony.

He 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 two days) by enabling phase retuning to a new time zone's cues.

These results literally and figuratively bring the inner workings of biological clocks into the light, said first author Logan Roberts.

Study results appear online in Current Biology.