The brain cells around a mouse’s neurons play a bigger role than merely filling space, a Johns Hopkins University study shows. Once activated by the fight-or-flight chemical norepinephrine these cells called astrocytes can monitor and respond to nearby neural activity. However, since the astrocytes can alter the activity of neurons, it is likely that they may help control the brain’s ability to focus as well.
Using advanced microscopy researchers observed the brain cells of genetically engineered mice over long periods of time to learn how these abundant astrocyte cells are controlled. They found that exposure to light does not necessarily activate the vision processing area of the brain, but at times they were active, even in the dark. The team discovered that this is because the astrocytes needed a “wake up” signal before they could respond to nearby neurons. They further found that norepinephrine primes the astrocytes in both locations to “listen in” on nearby neuronal activity.
For example, as lead researcher Dr Bergles says, “It is known that astrocytes can regulate local blood flow, provide energy to neurons and release signalling molecules that alter neuronal activity. They could be doing all or any of this in response to activation. Also, there is a possibility of their acting as a sort of megaphone to broadcast local norepinephrine signals to neurons all over the brain.” Be this as it may, we now know that astrocytes are not idle loiterers.