A tiny population of neurons can unlock the body’s clock
From the WashU Newsroom…
Travel by airplane has opened the door to experiencing different cultures and exploring natural wonders. That is, if you can get past the jet lag.
But what if you could take control of the brain’s daily timing system? Biologists at Washington University in St. Louis unlocked a cure for jet lag in mice by activating a small subset of the neurons involved in setting daily rhythms, as reported in a July 12 advance online publication of Neuron.
All essential body functions are highly synchronized with local time by the body’s daily, or circadian, clock. A small spot at the very bottom of the brain, close to the roof of the mouth, reminds us to wake up and go to sleep at a regular time each day. This master clock is referred to as the suprachiasmatic nucleus, or SCN.
When this system is disturbed — by shift work or crossing time zones, for example — the 20,000 neurons in the SCN struggle to adjust the body to the new schedule. Stimulating just 10 percent of these neurons to fire with the right pattern of electrical activity caused mice to rapidly shift to the new daily schedule, the researchers found.
“Just like your watch is good at keeping time but is useless unless you can set it to local time,” said Erik Herzog, professor of biology in Arts & Sciences, “we wondered how the body clock adjusts to its local time.”
“We hypothesized that VIP neurons are like the grandmothers who are in charge of telling everyone what to do,” Herzog said. There are only about 2,000 VIP neurons in the SCN of people and mice.Herzog and his lab suspected a small subset of SCN neurons are involved because it produces vasoactive intestinal polypeptide or VIP, an essential compound that neurons use to communicate and synchronize their daily rhythms with one another.