Poor sleep in a new environment is a typical annoyance for many, and now the old problem has a new set of initials—FNE or first-night effect—thanks to a team of scientists at Brown University. According to a recent article titled “Night Watch in One Brain Hemisphere during Sleep Associated with the First-Night Effect in Humans” published in Current Biology and a summary article in My Modern Met, the FNE phenomenon has a physiological root.
“Led by Masako Tamaki, the study discovered that one of the hemispheres of the brain remains alert and vigilant for strange stimuli,” writes Madeleine Muzdakis. “On the first night in a new environment, the researchers found the subjects’ brains showed ‘regional interhemispheric asymmetry of sleep depth’ in their first sleep cycle. This means that one hemisphere of the brain (usually the left) showed more activity that was mostly focused in the default mode network (DMN).”
The researchers also tested the reaction times of both the slumbering and alert hemispheres. Muzdakis reports: “They found that the less-sleeping hemisphere responded to stimuli—such as a dog barking or door slamming—more quickly than the half of the brain in deeper sleep. For this reason, the researchers not only postulate that the semi-alert hemisphere is the reason for FNE, but that FNE itself is a manifestation of the human brain keeping a ‘night watch’ in a new environment.”
Source: Current Biology