Sleep Twitches 'Light Up' The Brain During Sleep

Recent findings published in the journal Current Biology show that twitches made during sleep actually activate the brains differently than when the body's awake.

"Every time we move while awake, there is a mechanism in our brain that allows us to understand that it is we who made the movement," said Alexandre Tiriac, a fifth-year graduate student in psychology at the UI and first author of the study, in a news release. "But twitches seem to be different in that the brain is unaware that they are self-generated. And this difference between sleep and wake movements may be critical for how twitches, which are most frequent in early infancy, contribute to brain development."

The study found that during rapid eye movement (REM) sleep, many experience twitches that activate circuits throughout the developing brain.

Furthermore, the findings imply that twitches teach newborns about their limbs and what they can do with them.

For the study, researchers examined the brain activity of unesthetized rats between eight and 10 days brain activity. Next, they measured the brain activity wanesthetized while the animals were awake and moving and again while the rats were in REM sleep and twitching.

"We noticed there was a lot of brain activity during sleep movements but not when these animals were awake and moving," Tiriac added

Researchers said that they believe that these sensations may be caused from twitching limbs made during REM sleep being processed differently in the brain from awake movements as they lacked what is known as "corollary discharge."

Mark Blumberg, a psychology professor at the UI and senior author of the study, added that this latest discovery is further evidence that sleep twitches- whether in dogs, cats or humans-are connected to brain development, not dreams.

"Because twitches are so different from wake movements," he concluded, "these data put another nail in the coffin of the 'chasing rabbits' interpretation of twitches."