2023-04-18 07:48:41
The work of a team led by Clément Léna and Daniela Popa, Inserm research directors at the ENS Institute of Biology, published in Nature Communications reveal the importance of the cerebellum in emotions. This region of the brain, best known for its role in motor control, also acts on an area of the prefrontal cortex involved in emotions, and through this regulates the extinction of aversive memories. This work opens the way to a better understanding of the regulation of emotions in mood disorders, but also in various pathological conditions such as perinatal anoxia, brain tumors or the effects of alcohol.
To survive or simply optimize one’s existence, it is better to be able to recognize the risks and adjust one’s behavior accordingly. Through associative mechanisms, the brain learns to identify warning signs of danger. These associations must be continually updated, in particular to recognize the harmlessness of signs previously perceived as threatening but no longer proving to be associated with danger.
A defect in the processes of neutralizing such cues would expose the accumulation of only negative associations, leading, for example, to indefinitely maintaining intense emotional responses to past trauma. However, rather than forgetting these clues, which have become negligible, one of the methods employed by the brain is to entrust the prefrontal cortex with the task of repressing their aversive meaning, thanks to a real learning of harmlessness, also called extinction.
By studying the brains of mice, the team made up of researchers from ENS-PSL and Inserm showed that the area of the prefrontal cortex in charge of this function receives information from the cerebellum (via a relay in the thalamus, see figure). The researchers succeeded in carrying out a targeted inactivation of this projection by introducing artificial inhibitory receptors into it. They observed that when this circuit is inactivated, the fear response to a stimulus that no longer represents a danger is abnormally prolonged, indicating a learning deficit.
Recordings of activity in this brain circuit then revealed that the cerebellum participates in learning to repress negative memories by stopping rhythmic brain activities associated with the state of fear.
These works complete a previous study from the same team, which had demonstrated that the intensity of the “clues – dangers” association was also under the control of the cerebellum, by projections to a region of the brain other than the prefrontal cortex.
While the cerebellum is well known for its role in the motor system (the motor effects of alcohol, for example, are almost entirely due to an effect on the cerebellum), these demonstrations of cerebellar regulation of formation and the extinction of emotional memory are important. They show that this structure acts on the key processes of emotion regulation generated by our past experiences. This work opens the way to a better understanding of the regulation of emotions in mood disorders, but also in various pathological conditions, linked for example to the sensitivity of the cerebellum to perinatal anoxia, to brain tumors or to the effects alcohol.
Press release, Inserm, April 14, 2023
1681870071
#Mastering #fear #cerebellum #unexpected #partner #mood #disorders