A sustained state of vigilance will generate a different type of memory than a momentary startle, and these differences are linked to distinct signaling molecules in the brains of mice.
Researchers at the RIKEN Center for Brain Science (CBS) have visualized these dynamics in the living mouse brain for the first time, observing fast and slow molecular pathways that support memory function.
These processes take place in brain cells called astrocytes, revealing another important way in which these cells help neurons.
Norepinephrine, also called noradrenaline, is a dual hormone and neurotransmitter that prepares the body for action.
Previous research has shown that norepinephrine release is important for modifying synapses, the connections between neurons that form and consolidate memories. Astrocytes are the crucial mediators of these changes, and the researchers were interested in observing, in real time, what happens in these cells when mice are learning.
Their study was published in Nature Communications on January 24.
First, the team artificially stimulated brain cells with light, a method called optogenetics, to induce norepinephrine release. They focused on noradrenergic neurons originating in a part of the brain called the locus coeruleus.
Norepinephrine release launched two distinct chains of molecular events, the first involving calcium activity and the second cAMP, an important signaling molecule. Calcium levels in astrocytes were quick to become elevated following norepinephrine release, while cAMP levels had a slower but more sustained increase.
We think these fast and slow dynamics are significant because calcium elevation in astrocytes promotes synaptic plasticity, or the ability of cells to form new memory connections, while cAMP elevation mobilizes energy metabolism for memory consolidation." Hajime Hirase, senior author and team leader, RIKEN CBS Related Stories
Also in Industry News
How to decide whether or not to start treatment for prostate cancer?
Analysis of the SARS-CoV-2 proteome via visual tools
$65m investment increases British Patient Capital’s exposure to life sciences and health technology