Search Here

It is no surprise that a good night's rest promotes an overall healthier mindset. Not only does sleep rejuvenate the brain and prepare it for the new day's tasks, it also restores the body. When people lose sleep, their behaviors and moods can be greatly affected. Due to several variables, such as stress from work and excitement from games, the natural process of falling asleep can be disrupted. In a new study, researchers found that the quality of the time spent during wakefulness affects how long it takes for someone to fall asleep.

"This study supports the idea that subjective sleepiness is influenced by the quality of experiences right before bedtime. Are you reluctantly awake or excited to be awake?" said Dr. Masashi Yanagisawa, professor of molecular genetics and a Howard Hughes Medical Institute investigator at UT Southwestern. Yanagisawa is the principal author of this study and he worked with co-author Dr. Robert Greene, UT Southwestern professor of psychiatry and a physician at the Dallas VA Medical Center and Dr. Ayako Suzuki, a postdoctoral researcher.

The researchers studied the role of wakefulness and its influence on how the body falls asleep. They experimented on three groups of mice that were bred to be genetically identical. The first group of mice acted as the control group and was able to sleep and wake up whenever they liked. The second group of mice was kept awake for six hours after their bedtime. The researchers utilized an exciting method of keeping them alert, which involved changing their cages every hour. Once mice are introduced to a new cage, they naturally start to explore the area. The last group of mice also was sleep deprived for six hours. In this group, the researchers kept them awake by gently tapping or waving a hand in front of the sleepy mice.

"The need to sleep is as high in the cage-changing group as in the gentle-handling group, but the cage-changers didn't feel sleepy at all. Their time to fall asleep was nearly the same as the free-sleeping, well-rested control group," Yanagisawa said.

The researchers found that the last group of mice was able to fall asleep a lot faster than the group of mice that experienced cage changes. The researchers also identified two different proteins responsible for the time it took to fall asleep and for sleep deprivation. Phosphorylated dynamin 1 levels appeared to be responsible for the time it took to fall asleep and phosphorylated N-myc appeared to regulate sleep deprivation.

"These proteins are completely new to sleep research and have never before been linked to sleep need and wakefulness," Yanagisawa said. The researchers hope that more studies looking into these proteins could help create new methods of treating people with sleep disorders.

The findings were published in the Proceedings of the National Academy of Sciences.