Immune Cells Do Brain Maintenance During Sleep You’ve probably heard that research has shown that the brain clears up waste and updates memories during sleep. But a new study has found that specialized immune cells are hard at work in the brain during sleep too. The findings, which were published in Nature Neuroscience, show that the signals in our brain that modulate sleep turn the immune system on and off. Even during sleep, the microglia (immune cells) work to fight damage or infection in the brain and address “wear and tear” in the brain—even during sleep. You can read more about the research here: https://www.medicalnewstoday.com/articles/326776.php#2