Chronic sleep deprivation could have more lasting effects on the brain than previously realized, according to a new study in mice.
Researchers from the University of Pennsylvania Perelman School of Medicine and Peking University found that chronic sleep loss is associated with injury and loss of locus coeruleus (LC) neurons in the brain, which are needed for alertness and optimal thinking.
The researchers looked at how different patterns of sleep -- normal rest, short-term periods of wakefulness and long-term periods of wakefulness -- affected these LC neurons in mice. They found that when they subjected the mice to short-term sleep loss, there was upregulation of a specific protein (known to play a role in energy production) by the LC neurons, which in turn protected the neurons from being injured by the sleep loss.
However, when the mice were subjected to the long-term sleep loss -- over several days -- the upregulation of this protein by the LC neurons was reduced, leading to cell death. Ultimately, 25 percent of the LC neurons were lost in the mice subjected to the long-term sleep loss.
Because the study was only conducted in mice, researchers noted more work is needed to see if something similar happens in humans. It's also possible that other factors -- such as diet, aging or conditions like diabetes -- could affect how much the LC neurons are injured in humans when subjected to sleep loss.
The new findings are published in The Journal of Neuroscience.