Almost everybody has had the experience, of not being able to get a good night’s sleep the first night you spend in a hotel or a vacation destination.  Most think it is just in your mind, because you seem to sleep better from the second night on.

New research is saying that it is in your mind, well, actually your brain, after all.  Researchers at Brown University measured brain activity on 35 participants over two nights, spaced a week apart, in a sleep lab, and found the first night showed an interesting pattern of brain activity.

According to usnews.com, a particular network in the left hemisphere of the subjects brains indicated greater activity than the right hemisphere, while the participants were experiencing a phase of deep sleep, known as slow-wave sleep.

As the researchers played sounds into the right ear of the sleepers to stimulate the left hemisphere of the brain, the subjects were more likely to be awakened and were more alert after waking, than when sounds were played in the opposite ear.

When the experiment was repeated on the second night, the differences in brain activity were not significantly different, not even in the network that indicated activity the night before.  The researchers say that particular network, called the default-mode network, has a tendency to keep running when the rest of the brain is mostly idle.

The experiment only involved the first slow-wave sleep phase, so the authors of the study aren’t sure if the left hemisphere network continues to function in the same way all through the sleep cycle, or if the networks in each hemisphere work in tandem to achieve the same results.

Yuka Sasaki, on of the study’s corresponding authors and a research associate professor of cognitive linguistic and psychological sciences at Brown, said in a release from the university, “In Japan they say, ‘if you change your pillow, you can’t sleep.’  You don’t sleep very well in a new place. We all know about it.”

The researchers believe a part of the brain remains on alert to protect you from dangers or potential threats in your new surroundings, and that may help explain the inability to get that first good night’s rest.

Findings from the work were published in the journal Current Biology.