Sleepless nights lead to sluggish brain activity

By Dr. Ananya Mandal, MDNov 6 2017

A new study has shown that some brain cells actually slow down if a person has not got adequate sleep at night. This leads to periods of mental lapses. Researchers of University of California, Los Angeles (UCLA) and Tel Aviv University have proven this in their published study that appeared in the journal Nature Medicine online this Monday (6th of November 2017).

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The team of researchers measured activities from certain nerves directly in 12 persons. They found that sleep deprivation leads to slower and weaker bursts of electrical activity in the nerves. Dr. Itzhak Fried, professor of neurosurgery at the David Geffen School of Medicine, UCLA and author of this study said that this was the explanation of why sleep deprivation leads to impairment of several mental functions. Fried explained that for example if a person is driving a car and another person jumps in front of it, a sleep deprived person would have a different response than one who has had adequate sleep.

The patients enrolled in this study were actually being evaluated before surgery because they had severe epilepsy and needed surgery. These findings were found incidentally during the evaluation. The team had placed wires in the brain to detect the origin of the electrical bursts in the brain that was leading to the seizures or convulsions in the epileptics. Now the researchers could actually monitor several hundreds of nerves in the brain cells for days. Some epilepsy patients develop seizures on sleep deprivation. To trigger seizures so as to know the seizure origins in the brain the researchers had sleep deprived the patients for evaluation under controlled situations. Now they also found what happens to the brain if it is sleep deprived.

After sleep deprivation, the patients were asked to categorize certain pictures of faces, places and animals as quickly as possible to check for their mental abilities. As they were faced with an image, regions in their brains lit up as they processed the image. Fried explained that this is a reflection of how the brain reacts to different things and situations around us. Four of the patients stayed up all night and then were asked to look at the pictures. Now the researchers noted that the neurons had become sluggish and slower to respond to the images.

Lead author Yuval Nir of Tel Aviv University said that it was fascinating to note how lack of sleep “dampened brain cell activity”. “Unlike the usual rapid reaction, the neurons responded slowly and fired more weakly, and their transmissions dragged on longer than usual,” he explained. Fried said, “The responses are diminished, and they are smeared over longer periods of time.” The ability of the neurons or the nerve cells to communicate between each other is slowed leading to the mental lapses. He said this affects the perception as well as memory. In addition, the study also found that some areas of the brain are more affected with sleep deprivation than others.

Fried warned that driving especially is dangerous when a person is sleep deprived and that is evident from this study. The Centers for Disease Control and Prevention (CDC) estimates from the information provided by the National Highway Traffic Safety Administration that drowsiness during driving is responsible for over 70,000 crashes and accidents annually in the United States. Fried also said that too many doctors are sleep deprived working for long hours and that too impairs judgment and efficacy. He cited his own example as a neurosurgeon.

The research received support from the National Institute of Neurological Disorders and Stroke, the National Institute of Mental Health and other organizations.