Abnormal activation of the social brain network in children with autism spectrum disorder: an FMRI study

Abstract

Objective: The aim of this study is to investigate abnormal findings of social brain network in Korean children with autism spectrum disorder (ASD) compared with typically developing children (TDC).

Methods: Functional magnetic resonance imaging (fMRI) was performed to examine brain activations during the processing of emotional faces (happy, fearful, and neutral) in 17 children with ASD, 24 TDC.

Results: When emotional face stimuli were given to children with ASD, various areas of the social brain relevant to social cognition showed reduced activation. Specifically, ASD children exhibited less activation in the right amygdala (AMY), right superior temporal sulcus (STS) and right inferior frontal gyrus (IFG) than TDC group when fearful faces were shown. Activation of left insular cortex and right IFG in response to happy faces was less in the ASD group. Similar findings were also found in left superior insular gyrus and right insula in case of neutral stimulation.

Conclusion: These findings suggest that children with ASD have different processing of social and emotional experience at the neural level. In other words, the deficit of social cognition in ASD could be explained by the deterioration of the capacity for visual analysis of emotional faces, the subsequent inner imitation through mirror neuron system (MNS), and the ability to transmit it to the limbic system and to process the transmitted emotion.

Keywords: Autism spectrum disorder; Social brain network; Social cognition; fMRI.

Figure 1

Paradigm design and examples of the stimuli used in the emotional face perception task. The emotional face stimuli for each category (happy, fear, and neutral) were presented as a block unit. In a block, each emotional face picture was shown for 2 seconds (a blank screen was shown for 1 second immediately after the picture), and six emotional face pictures were shown per block.

Figure 2

Main effect of emotional face perception (A and B: fearful stimuli, C and D: happy stimuli, E and F: neutral stimuli). Reduced activities were observed in several parts of the social brain network in the ASD group compared with the TDC group while pictures of emotional faces were shown (uncorrected, p<0.01). Brain regions indicated are right superior temporal sulcus (STS) (A), right inferior frontal gyrus (IFG) (B); left insular cortex (C); right inferior frontal gyrus (IFG) (D); left superior insular sulcus (E); left superior insular sulcus (F). ASD: autism spectrum disorder, TDC: typically developing children, A: anterior, P: posterior, R: right, L: left.