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 had not known what mechanism activates neurons during fear extinction.
The neurotransmitter dopamine was found to be involved in this mechanism. The ventral tegmental area sends dopamine signals to the amygdala, where neurons that initiate and suppress fear could respond to these signals. In further experiments, the scientists increased the amount of dopamine used to send 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. They say the discovery points to new targets for treating PTSD and other mental disorders. Further experiments should confirm the potential of this 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.
