Reduced neural habituation in the amygdala and social impairments inautism spectrum disorders

Kleinhans, N. M., PhD., Johnson, L. C., Richards, T., Mahurin, R., Greenson, J., Dawson,G., & Aylward, E. (2009). Reduced neural habituation in the amygdala and social impairments inautism spectrum disorders. The American Journal of Psychiatry, 166(4), 467-75. Retrieved September 15, 2011, from Proquest.

The purpose of this study was to examine whether amygdala dysfunction is distinguished by abnormalities in habituation. The researchers also wanted to examine whether or not the amygdala habituation rate has any relation to social impairment. From previous studies it has been thought to be that an important factor in social impairment in individuals with autism spectrum disorders is amygdala dysfunction. Within this study a MRI was used to measure the variations in amygdale and fusiform gyrus activation to facial stimili that was neutral in adults with the disorder. The group that was being compared had higher amygdala habituation than the group with autism spectrum disorders. However, overall, there were no major differences in fusiform habituation. Also in the autism spectrum group, the results showed that severe social impairment was associated with lower habituation levels of the amygdala. So, this suggests that in autism spectrum disorders there is hyperarousal in the amygdala as a response to stimuli that is socially significant. It is also suggested that amygdala arousal over a certain period of time may play a role in social deficits of people with autism spectrum disorders.