Scientists talked about the role of astrocytes in the formation of fear memory

Scientists at the University of Arizona, together with researchers from the US National Institutes of Health (NIH), have found that astrocytes, brain cells that were previously considered auxiliary, are directly involved in the formation, reproduction and extinction of fear memories. Changes in their activity affected the intensity of fear reactions in mice. This was reported on April 4 in the journal Science Daily.

"For the first time, we have been able to show that astrocytes encode and support the neural transmission of fear signals," said Lindsay Halladay, one of the lead authors of the work, an assistant professor in the Department of Neuroscience at the University of Arizona.

Astrocytes, star—shaped cells that permeate brain tissue with long appendages and surrounding neurons, have been perceived for decades solely as structural and metabolic support for nerve cells. A new study refutes these ideas: it turned out that astrocytes are just as important for processing threat information as the neurons themselves.

The work was carried out on a mouse model using fluorescent sensors that made it possible to monitor the activity of astrocytes in real time. The experiments focused on the amygdala, a brain structure responsible for processing fear. The activity of astrocytes increased at the time of the formation of the fear memory and during its subsequent reproduction, and decreased as the fear faded.

The researchers intentionally amplified and weakened the signals that astrocytes send to neighboring neurons. Strengthening made fearful memories more intense, weakening reduced the severity of the reaction. This proves that astrocytes do not passively accompany neural processes, but actively form them.

Disruption of astrocyte function made it difficult for neurons to form patterns of activity associated with fear and prevented the transmission of signals about defensive reactions to other parts of the brain. The influence of these cells extended to the prefrontal cortex, the area responsible for decision—making: astrocytes, apparently, help the brain not only to remember threats, but also to choose appropriate responses.

According to Halladay, understanding the role of astrocytes in the entire fear chain can answer a key question: why do people with anxiety disorders and post-traumatic stress disorder (PTSD) react with fear to obviously safe situations.

Medical Xpress magazine reported on February 25 that scientists from the University of Bochum have proven that the process of getting rid of fear can be significantly accelerated by activating certain neurons in the brain. This discovery could be an important step in the development of new treatments for anxiety disorders such as post-traumatic stress disorder (PTSD).

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