Jet Lag: Activating Neurons in the Brain Might Be Key to Shifting Internal Clock, New Research Shows

Summer trips across time zones may get a bit easier thanks to a new finding from scientists in St. Louis.

New research from scientists at the city’s Washington University discovered a possible way to fight jet lag. In a study published in Neuron on Thursday, the scientists detailed how activating neurons in the brain could shift your internal clock.

Jet lag occurs when someone travels across different time zones. A person’s circadian rhythm—the physical, behavioral and mental changes that occur throughout the day—is set to his or her original time zone. When traveling to a new one, the circadian rhythm takes time to reset, causing fatigue, difficulty focusing or even stomach problems. Now there might be a way to skip that exhausting first day of traveling.

Circadian rhythms are controlled by your internal “clock,” a cluster of 20,000 nerve cells, or neurons, in the part of the brain called the hypothalamus. These cells form the suprachiasmatic nucleus (SCN).

Erik Herzog, a professor at Washington University, whose lab conducted the study, said in a statement, “Just like your watch is good at keeping time but is useless unless you can set it to local time, we wondered how the body clock adjusts to its local time.”

His team hypothesized that about 2,000 of the cells in the SCN controlled the others, and appropriately called these the “grandmother” neurons. These special neurons produce vasoactive intestinal polypeptide, or VIP. They use VIP to communicate with the other neurons to sync their rhythms, possibly each time someone enters a new time zone. 

To test if activating the grandmother neurons would help reset someone’s internal rhythm, the scientists kept mice in total darkness during the day and night, giving them no clues about the time. At the same time every day, the scientists activated the mice’s grandmother cells to use VIP with optogenetics, a tool that uses light to control cells. This mimicked what a normal schedule would be like in the brain. When the scientists activated the grandmother cells at irregular times, the cells also released VIP to reset the clock.

“VIP, we think, is the juice that is capable of shifting the clock faster,” Herzog said.

Now the scientists hope to find a way to use this discovery to help humans fight jet lag. Thanks to these grandmother neurons, scientists may be able to find a way to encourage VIP cells in humans to release VIP to reset the circadian rhythm—and travel across time zones may get easier.


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