The Institute for Basic Science on Sept. 18 said anxiety and fear do not easily fade in people with autism because of lower activity of specific neurons in the brain, adding that activating such neurons can erase memories of fear. (iClickArt) (Unauthorized reproduction and redistribution of this image is prohibited under copyright law.)

By Lee Dasom

The Institute for Basic Science (IBS) on Sept. 18 said it found a clue toward alleviating post-traumatic stress disorder (PTSD) in experiments with autistic mice.

Using a genetic mutation discovered in autistic patients, a research team led by Kim Eunjoon, director of the IBS' Center for Synaptic Brain Dysfunctions, found that inactivity of the basolateral amygdala, a structure in the brain crucial to the development and expression of anxiety-related behavior, is a key cause of disorders that prevent the extinction of memories of fear and long-term responses to anxiety.

In its experiments, the team focused on mutations of the GRIN2B gene, which are known to be associated with brain and mental disorders such as autism, intellectual disability and developmental delay.

Mice with such mutations were found to struggle to forget memories of fear after undergoing a threatening situation and showed symptoms of PTSD over time.

Additional studies also confirmed that the basolateral amygdala of autistic mice were insufficiently activated after trauma and that excitatory neurons in that region remained inhibited for a long time.

Through chemogenetic techniques, the team artificially activated excitatory neurons in the basolateral amygdala to normalize previously suppressed neural transmission and excitability. The restoration of the function to erase memories of fear to normal levels led to the alleviation of long-term anxiety responses.

"This is the first result to identify the cause of PTSD-like symptoms in autistic patients as long-term inhibition of excitatory neurons in the basolateral amygdala," Kim said. "Basolateral amygdala activity could provide important clues for developing PTSD treatment strategies for autistic patients."

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