Ever wondered why some people can sleep right through an earthquake, while others wake up for the slightest reasons? Here's an answer.
"We found that by measuring brain waves during sleep, we could learn a lot about how well a person's brain can block the negative effects of sounds; the more sleep spindles your brain produces, the more likely you'll stay asleep, even when confronted with noise," said Jeffrey Ellenbogen of Harvard Medical School.
Sleep spindles refer to brief bursts of faster-frequency waves, generated by a portion of the brain called the thalamus.
"The thalamus is likely preventing sensory information from getting to areas of the brain that perceive and react to sound," said Ellenbogen.
Ellenbogen and his colleagues observed brain patterns of study participants as they slept in the lab for three nights.
The first night was quiet and the second and third nights were noisy, as the researchers introduced a variety of sounds-a telephone ringing, people talking, hospital-based mechanical sounds, and so on.
"The effect of sleep spindles was so pronounced that we could see it even after just a single night," he said.
"Our goal is to find brain-based solutions that integrate a sleeping person into their modern environment, such that sleep is maintained even in the face of noises. This finding gets us one important step closer to realizing that goal," he added.
"In the meantime, it still doesn't hurt to put up a sign that says 'Shhh!'" he said.
The study is detailed in the August 10th issue of Current Biology.