The old adage about sleeping with one eye open in an unfamiliar place may not be too far off the mark. A new study suggests that one half of the brain remains on high alert during the first night of sleep in a new space.
Over the course of three experiments on 35 young, healthy volunteers, researchers measured brain activity during two consecutive nights of slumber. They consistently found that part of the left side of the brain remained more active than the right side only on the first night, specifically during a deep sleep phase known as slow-wave . . .