The mirror neuron system compensates for amygdala dysfunction- associated social deficits in individuals with higher autistic traits

The amygdala is a core node in the social brain which exhibits structural and functional abnormalities in Autism spectrum disorder and there is evidence that the mirror neuron system (MNS) can functionally compensate for impaired emotion processing following amygdala lesions. In the current study, we employed an fMRI paradigm in 241 subjects investigating MNS and amygdala responses to observation, imagination and imitation of dynamic facial expressions and whether these differed in individuals with higher ( n = 77) as opposed to lower ( n = 79) autistic traits. Results indicated that individuals with higher compared to lower autistic traits showed worse recognition memory for fearful faces, smaller real-life social networks, and decreased left basolateral amygdala (BLA) responses to imitation. Additionally, functional connectivity between the left BLA and the left inferior frontal gyrus (IFG) as well as some other MNS regions was increased in individuals with higher autistic traits, es-pecially during imitation of fearful expressions. The left BLA-IFG connectivity significantly moderated the autistic group differences on recognition memory for fearful faces, indicating that increased amygdala-MNS connectivity could diminish the social behavioral differences between higher and lower autistic trait groups. Overall, find-ings demonstrate decreased imitation-related amygdala activity in individuals with higher autistic traits in the context of increased amygdala-MNS connectivity which may functionally compensate for amygdala dysfunction and social deficits. Training targeting the MNS may capitalize on this compensatory mechanism for therapeutic benefits in Autism spectrum disorder.

Automated summary

The amygdala, a core node in the social brain, shows structural and functional abnormalities in Autism spectrum disorder. The mirror neuron system (MNS) can compensate for impaired emotion processing in individuals with amygdala lesions. This study found that individuals with higher autistic traits had worse recognition memory for fearful faces, smaller social networks, and decreased amygdala responses to imitation. Increased connectivity between the amygdala and the inferior frontal gyrus was also observed in individuals with higher autistic traits. This increased connectivity may help diminish social behavioral differences between individuals with higher and lower autistic traits.