New research suggests that a lack of sleep hampers communication between brain cells, causing temporary mental errors that affect memory and visual perception.
That can lead to problems ranging from minor ones such as forgetting your keys when you leave the house, to more serious consequences such as lack of awareness while driving.
“We discovered that starving the body of sleep also robs neurons of the ability to function properly. This leads to (mental) lapses in how we perceive and react to the world around us,” said study senior author Dr. Itzhak Fried, a professor of neurosurgery at the University of California, Los Angeles and Tel Aviv University in Israel.
Fried added that severe fatigue “exerts a similar influence on the brain to drinking too much. Yet no legal or medical standards exist for identifying overtired drivers on the road the same way we target drunk drivers.”
The study included 12 epilepsy patients who had electrodes placed in their brains prior to surgery to pinpoint the origin of their seizures. They were kept awake all night to provoke seizures.
The patients were asked to categorize a number of images as quickly as possible while the electrodes recorded the activity of brain cells that control memory and visual perception. As the patients grew more sleepy, these brain cells slowed down and the task grew more difficult.
“We were fascinated to observe how sleep deprivation dampened brain cell activity,” study lead author Yuval Nir said in a UCLA news release. He is a researcher at Tel Aviv University’s Department of Physiology and Pharmacology.
“Unlike the usual rapid reaction,” Nir added, “the neurons responded slowly and fired more weakly, and their transmissions dragged on longer than usual.”
The reduced brain cell activity was accompanied by slower brain waves.
“Slow, sleep-like waves disrupted the patients’ brain activity and performance of tasks,” Fried said. “This phenomenon suggests that select regions of the patients’ brains were dozing, causing mental lapses, while the rest of the brain was awake and running as usual.”
The study, published online Nov. 6 in the journal Nature Medicine, underscores how dangerous a lack of sleep can be, according to the researchers.
Previous research has linked sleep deprivation to increased risk of depression, obesity, diabetes, heart attack and stroke.
Fried and Nir plan to continue studying the benefits of sleep and the mechanism behind the cellular glitches that precede the mental lapses.
The research was supported by the U.S. National Institute of Neurological Disorders and Stroke, the U.S. National Institute of Mental Health and the Israel Science Foundation, among others.