Here's why you have trouble sleeping somewhere new

If you have ever had a hard time sleeping on the first night in a new place, you may want to blame your brain's guarding system.

According to a new study, when people sleep in an unfamiliar place for the first time, one hemisphere of the brain stays more awake to keep watch.

Researcher Yuka Sasaki of Brown University said that it is known that marine animals and some birds show unihemispheric sleep, one awake and the other asleep. While the human brain doesn't show the same degree of asymmetry that the brains of marine animals do, the new findings suggest that our brains may have a miniature system of what whales and dolphins have.

Sasaki and her colleagues, including Masako Tamaki, Ji Won Bang, and Takeo Watanabe, wanted to know the reason behind the phenomenon known as the first-night effect and so they used advanced neuroimaging techniques to analyze the sleeping brain.

Sasaki says people might be able to reduce this effect by bringing their own pillow or staying in hotels with similar accommodations. It's also possible that people who have to sleep in new places often learn to turn this night surveillance off.

"Human's brains are very flexible," she says. "Thus, people who often are in new places may not necessarily have poor sleep on a regular basis."

She says their lab is now trying to temporarily knock out the "awake" part of the brain by transcranial magnetic stimulation to see whether sleep improves.

The study appears in the Cell Press journal Current Biology.