Nat Neurosci: "garden at night" -- immune cells repair the brain during sleep

October 22, 2019 / BIOON / -- previous studies have shown that many "good" things happen in the brain during sleep: for example, learning and memory are consolidated, and metabolic waste is eliminated However, recent studies show for the first time that immune cells in the brain called microglia are also very active when we sleep The related research is based on mice, and the results are published in the recent journal Nature Neuroscience The findings have important implications for brain plasticity, autism spectrum disorders, schizophrenia and dementia The author is Ania, a professor at the Del Monte Institute, University of Rochester Medical Center "It is generally believed that the dynamic process of microglia does not depend on the behavior of the body," the Majewska said "This study raises the opposite view that signals in the brain that regulate sleep and wakefulness can also serve as a switch to turn off and turn on the immune system." (image source: www Pixabay Com) microglia usually "patrol" in the brain and spinal cord When abnormal conditions are found, they will quickly take action to eliminate the fragments in the infected or phagocytized dead cell tissues Until recently, Majewska et al showed that these cells also play an important role in brain plasticity The so-called brain plasticity refers to the continuous process of connecting and reconnecting complex networks and connections between nerve cells in the development process, which has an important impact on learning, memory, cognitive and motor functions In previous studies, Majewska's laboratory has demonstrated the mechanism of synaptic interaction between microglia and neurons Microglia help to maintain the normal state and function of synaptic connections between nerve cells The role of noradrenaline in this process has also been pointed out in the current study Noradrenaline is a neurotransmitter that produces pressure signals in the central nervous system When we sleep, the chemical content in our brain is very low, but when it increases, it will wake up our nerve cells, make us wake up and become sensitive to the surrounding environment Studies have shown that noradrenaline acts on specific molecules called β 2-adrenoceptors, which are highly expressed in microglia When the chemical is present in the brain, microglia are affected and enter a "hibernating" state This study uses advanced imaging technology to enable researchers to observe the brain activity of living mice The study shows that when mice are exposed to high levels of noradrenaline, the activity of microglia decreases, unable to respond to local damage, and the role of microglia in reconnecting the brain network is also affected Dr rianne Stowell, the first author of the paper, said: "this work suggests that the remodeling and repair of neural circuits during sleep may be partially mediated by the dynamic interaction between microglia and the brain In general, this study also shows that microglia are very sensitive to signals regulating brain function, and the dynamic characteristics and functions of microglia are regulated by animal behavior " This study reinforces our understanding of the important relationship between sleep and brain health, and can help explain the established relationship between sleep disorders and the onset of neurodegenerative diseases such as Alzheimer's and Parkinson's Information source: the night Gardeners: immune cells rewire, repair brain while we sleep original source: rianne D Stowell, Grayson O side, Ryan P Dawes, Hanna n Batchelor, Kathryn a Lordy, Brendan s Whitelaw, mark B Stoessel, Jean M bidback, Edward brown, Mriganka Sur & Ania K Majewska Noradrenergic signaling in the wakeful state inhibits microglial surveillance and synaptic plasticity in the mouse visual cortex Nature Neuroscience , 2019 DOI: 10.1038/s41593-019-0514-0