Neuroscientists have identified a new target in the brain that supports the “freeze response” (a normal response to frightening or extremely painful situations) associated with triggering anxious and fearful behaviors.

Bristol University scientists say the discovery of a key pathway in the brain provides a potential new target for drugs to treat anxiety and mental disorders, which affect an estimated 264 million people worldwide.

It is pointed out that current medications that relieve anxiety are not always effective for all patients and often have undesirable side effects.

Understanding the brain networks and mechanisms that underlie fear and anxiety may provide a new way to develop better treatments for anxiety disorders.

Neuroscientists from the Bristol School of Physiology, Pharmacology and Neuroscience sought to investigate how the cerebellum, which is linked to many brain regions connected to survival networks, affects activity in another brain region called the pericentral gray area (PAG).

This PAG is at the center of central networks that coordinate survival mechanisms including fear-provoking coping responses such as “freezing”.

To investigate, the team fitted animal models with electrodes to record activity within the PAG region of the brain and applied a conditioning task, in which an auditory tone is paired with a small foot shock, leading to the formation of “fear memory” and “freezing,” a behavioral indicator of fear. . The team showed that within the PAG region of the brain, a subset of brain cells increased their response to the conditioned tone, consistent with fear memory encoding.

However, when cerebellar output was altered during conditioning, the subsequent timing of fear-related neural activity in the PAG became less accurate and the duration of fear-related freezing behavior was increased, confirming that gray matter interactions around the cerebellum contribute to fear conditioning processes.

The team showed that manipulation of the direct cerebellar pathway also caused impairments in conditioned fear freezing and ultrasound articulation.

“Until now, little has been understood about how the cerebellum modulates neuronal activity in other brain regions, particularly those related to fear and anxiety,” explain the study’s lead authors, Dr. Charlotte Lawrenson and Dr. Elena Pacey. Importantly, our results show that the cerebellum is part of the brain survival network that regulates fear memory processes over multiple time scales and in multiple ways, raising the possibility that dysfunctional interactions in the cerebellar survival network may underlie fear-related disorders and comorbidities.”

The study findings provide new insights into the way the PAG encodes fear memory, and also provide evidence that the cerebellum is an additional key structure in the list of brain regions that contribute to the fear/anxiety network and offer a new target for the treatment of psychiatric conditions including PTSD.