A type of cell often ignored in the brain plays a dynamic and surprisingly complex role in our ability to process information, according to a new research from the Oregon Health & Science University.
The study, published today in the magazine ScienceIt provides direct evidence of the real -time action of a star glial cell type, known as astrocytes, in the live brains of fruit flies. The abundant cell type, approximately 35% of all cells in the human brain, seems to be a key part of orchestrating a complex network that governs brain function.
“We hope that this begins to change fundamentally how the field thinks about astrocytes and its role in the mediation of neurophysiology and behavior,” said principal author Marc Freeman, Ph.D., director of the OHSU Vollum Institute. “In the long run, I should change the way people think about developing therapies for the regulation of attention, anxiety and mood.”
The discovery was replicated in rodent astrocytes, suggesting that it is an ancient feature of evolution that will probably be preserved in other mammals, including people.
“I think it is evolutionarily relevant to survival,” said principal author Kevin Guttenplan, Ph.D., postdoctoral scientist in Freeman’s laboratory. “If a tiger is behind you, you must quickly change how the entire brain regions are thinking: it is time to exclude everything else in your mind and focus completely on the brain to escape. It is not time to think about anything else.”
Construction of discoveries
At one point, it was thought that astrocytes played only a support role in providing food and eliminating neurons waste, cells that form the “wiring” of the brain by transmitting signals that allow us to think, act and feel sensations.
In 2016, Freeman and the collaborators documented for the first time that astrocytes also transmit signals between neurons.
Based on that discovery, researchers show some of the specific mechanisms that reveal as Those cells transmit signals. It turns out to be a highly complex interaction in which astrocytes can turn on and turn off their ability to respond to chemical neurotransmitters in the brain, such as dopamine and glutamate.
“Astrocytes are really large, and a single cell can have 100,000 synapses capable of sending signals to other cells,” Guttenplan said. “This mechanism allows them to choose which neurons listen. Being able to turn off some of these circuits allows astrocytes to make sense of the activity cacophony that occurs in the brain from one moment to another.”
The researchers found that manipulating this activation route within astrocytes could interrupt the behavior of fruit flies, highlighting the fact that these small changes can have a powerful impact.
‘Astrocytes can be the key’
Neuroscientists have previously assumed that astrocytes are a much more passive player in brain physiology.
“This study shows the importance of astrocytes in activity and neuronal behavior,” said Miriam Leenders, Ph.D., director of the National Institute of Neurological Disorders and stroke, part of the National Health Institutes, which financed the study. “It also demonstrates how fundamental neuroscience studies such as fruit fly can provide new fundamental ideas on brain physiology.”
New research reveals that astrocytes can respond directly to messages from all kinds of neurons. In this way, they play a role in the complex neuronal signaling network that drives cognition and controls physical behavior. In addition, they found that these responses dynamically change with the brain state, which allows astrocytes to orchestrate the complex network of neurons that allows the brain to attend the tasks in question.
“These cells do Actively control the neuronal activity, very powerfully, “said Guttenplan.
However, scientists warn that discovery complicates scientific understanding of how the brain works. Imagine a single astrocyte with thousands of synapses whose activation mechanisms can be activated or silenced alternately by innumerable signals that turn around. And then multiply it by millions of astrocytes throughout the human brain.
“It’s overwhelmingly complicated,” said Guttenplan.
At the same time, researchers find more and more evidence that glial cells play a role in brain lesions and neurodegenerative diseases such as Alzheimer’s and Parkinson diseases. Improving scientific understanding about how these cells work could help prevent diseases or develop treatments.
“In some of these conditions, things such as approach and attention are interrupted,” GutTeplan said. “Astrocytes can be the key.”
In addition to Freeman and Guttenplan, co -authors include Isa Maxwell, Ba, Erin Santos, Ba, Luke A. Borchardt, BS, Ernesto Manzo, Ph.D. and Leire Abalde-Atristain, Ph.D., from OHSU; and Rachel D. Kim, Ph.D., of the Faculty of Medicine of the University of New York.