A new study on mice published May 24 in the Journal of Neuroscience shows that missing out on sleep may cause parts of our brains to start eating other parts. And the Telegraph reports that's not necessarily something you want to be happening. The study revolves around two types of glial cells: astrocytes and microglial cells, according to New Scientist. Astrocytes get rid of worn-out and unnecessary synapses, while microglial cells do the same to damaged cells and debris. Science Alert reports both types of glial cells are active during sleep and play an important role in repairing the brain at the end of the day.
So it's somewhat unexpected that astrocytes stepped up their activity—more than doubling it—in the brains of chronically sleep-deprived mice. "We show for the first time that portions of synapses are literally eaten by astrocytes because of sleep loss,” researcher Michele Bellesi says. That may not be a bad thing, as the astrocytes were still going to work on the largest, most-used synapses. As Bellesi puts it, "They are like old pieces of furniture, and so probably need more attention and cleaning." What is more likely to be a problem is the increase in microglial activity caused by lack of sleep. Increased microglial activity has been linked to Alzheimer's in the past. It's unclear if the same thing happens in the brains of humans or if catching up on sleep can reverse it. (Not sleeping well? People may avoid you.)