Immune cells repair brains during sleepDate: 24 October 2019 Tags: Miscellaneous
Researchers have found that immune cells play an important role in reorganising the connections between nerve cells, fighting infections, and repairing damage, primarily while we sleep.
The immune cells called Microglia serve as the brain’s first responders, patrolling the brain and spinal cord and springing into action to stamp out infections or gobble up debris from dead cell tissue.
The research shows that the signals in our brain that modulate the sleep and awake state also act as a switch that turns the immune system off and on.
The microglia help maintain the health and function of the synapses and prune connections between nerve cells when they are no longer necessary for brain function.
The current study points to the role of norepinephrine, a neurotransmitter that signals arousal and stress in the central nervous system.
This chemical is present in low levels in the brain while we sleep, but when production ramps up it arouses our nerve cells, causing us to wake up and become alert.
The study showed that norepinephrine also acts on a specific receptor, the beta2 adrenergic receptor, which is expressed at high levels in microglia.
The study, which employed an advanced imaging technology that allows researchers to observe activity in the living brain. When exposed to high levels of norepinephrine, the microglia became inactive and were unable to respond to local injuries and pulled back from their role in rewiring brain networks.
This research also shows that microglia are exquisitely sensitive to signals that modulate brain function and that microglial dynamics and functions are modulated by the behavioural state of the animal.