By studying brain activity in mouse models, scientists have identified specific signals that trigger the process of rewriting traumatic memories after the danger has passed, Nature reports . Until now, scientists did not know what mechanism activates neurons during the process of fear extinction.
The mechanism involved the neurotransmitter dopamine. The ventral tegmental area sends dopamine signals to the amygdala, where fear-triggering and fear-suppressing neurons could respond to these signals. In further experiments, the scientists increased the amount of dopamine sending signals to fear-suppressing neurons and achieved a reduction in PTSD symptoms in mice.
“This stimulation produced a relaxed state more quickly, reducing fear symptoms,” the authors commented. According to them, the discovery points to new targets for the treatment of PTSD and other mental disorders. Further experiments should confirm the potential of the new approach for humans.
Previously, other scientists explained why some people develop clinical depression and post-traumatic stress disorder, while others do not. It turned out that the reason lies in differences in the prefrontal cortex of the brain.