"The neural mechanism of learned fear has an enormous survival value for animals, who must predict danger from seemingly neutral contexts," Cho said. This process is dysregulated, however, in PTSD, where overgeneralized and exaggerated fear responses cause symptoms including nightmares or unwanted memories of the trauma, avoidance of situations that trigger memories of the trauma, heightened reactions, anxiety, and depressed mood. A psychiatric disorder that can occur in people who have experienced or witnessed a traumatic event, such as war, assault, or disaster, PTSD can cause problems in daily life for months, and even years, in affected persons.Ĭho explained the capability of our brains to form a fear memory associated with a situation that predicts danger is highly adaptive since it enables us to learn from our past traumatic experiences and avoid those dangerous situations in the future. Post-traumatic stress disorder, or PTSD, affects 7% of the U.S. "Our study, therefore, also provides insights into developing therapeutic strategies to suppress maladaptive fear memories in post-traumatic stress disorder patients," he said. Our study now demonstrates for the first time that the formation of fear memory associated with a context indeed involves the strengthening of the connections between the hippocampus and amygdala."Īccording to Cho, weakening these connections could erase the fear memory. "Experimental evidence, however, has been weak.
"It has been hypothesized that fear memory is formed by strengthening the connections between the hippocampus and amygdala," said Jun-Hyeong Cho, an assistant professor in the Department of Molecular, Cell and Systems Biology and the study's lead author. Study results appear today in Nature Communications. Using a mouse model, the researchers demonstrated the formation of fear memory involves the strengthening of neural pathways between two brain areas: the hippocampus, which responds to a particular context and encodes it, and the amygdala, which triggers defensive behavior, including fear responses.
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