brain complexity: glial cells have functions II (Introduction)

by David Turell , Tuesday, September 08, 2020, 22:33 (1535 days ago) @ David Turell

Astrocytes are glial cells with many functions:

https://medicalxpress.com/news/2020-09-highlights-role-astrocytes-formation-remote.html

"Astrocytes are star-shaped cells that are known to have several functions, including the regulation of the metabolism, detoxification, tissue repair and providing nutrients to neurons. Recent studies have found that these cells can also change synaptic activity in the brain, thus impacting neuronal circuits at multiple levels.

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"The new findings represent a significant step forward in the understanding of astrocytes and their unique functions. Overall, they provide further evidence that astrocytes can shape neuronal networks in intricate ways and affect many cognitive functions, including the acquisition of remote memories.

"More specifically, the researchers observed that when a mouse was acquiring a new memory, ACC-projecting CA1 neurons were recruited in large numbers and neurons in the anterior cingulate cortex (ACC) were simultaneously activated. When they activated Gi pathways in astrocytes using chemogenetic techniques, however, the communication between CA3 and CA1 neurons was disturbed, which prevented activation in the ACC.

"As a result of their intervention on astrocytes, the projection typically observed between CA1 and ACC neurons in a mouse brain as the animal is learning something was repressed. This, in turn, appeared to impair the mice's ability to acquire remote memories.

"The findings suggest that astrocytes play an important role in the formation of remote memories in mice and potentially humans, via their ability to regulate the projection of neurons onto other areas of the brain. In this particular instance, they may control the communication between CA1 neurons and the ACC, which seems to be essential for remote memory formation.

"'We revealed another capacity of astrocytes: They affect their neighboring neurons based on their projection target," the researchers concluded in their paper. "This finding further expands the repertoire of sophisticated ways by which astrocytes shape neuronal networks and consequently high cognitive function.'"

Comment: It is not just the number of neurons or how complex the circuitry, it is also the helper cells. Astrocytes are the most numerous type of four different glial cell populations and the largest, and therefore the most important. We are still learning the full design of the brain.