Neurocognitive Mechanisms Underlying Social Atypicalities in Autism: Weak Amygdala's Emotional Modulation Hypothesis.

Wataru Sato,Takanori Kochiyama,Shota Uono

doi:10.3389/fpsyt.2020.00864

Abstract

Autism spectrum disorder (ASD) is a neurodevelopmental condition associated with atypicalities in social interaction. Although psychological and neuroimaging studies have revealed divergent impairments in psychological processes (e.g., emotion and perception) and neural activity (e.g., amygdala, superior temporal sulcus, and inferior frontal gyrus) related to the processing of social stimuli, it remains difficult to integrate these findings. In an effort to resolve this issue, we review our psychological and functional magnetic resonance imaging (fMRI) findings and present a hypothetical neurocognitive model. Our psychological study showed that emotional modulation of reflexive joint attention is impaired in individuals with ASD. Our fMRI study showed that modulation from the amygdala to the neocortex during observation of dynamic facial expressions is reduced in the ASD group. Based on these findings and other evidence, we hypothesize that weak modulation from the amygdala to the neocortex—through which emotion rapidly modulates various types of perceptual, cognitive, and motor processing functions—underlies the social atypicalities in individuals with ASD.

Highlights

Autism spectrum disorder (ASD) is a neurodevelopmental condition associated with atypicalities in reciprocal social interaction [1]
region of interest (ROI) analyses revealed that activities in the predefined brain regions during observing dynamic facial expressions were significantly lower in the ASD than the typically developing (TD) group
We used dynamic causal modeling (DCM) to compare three models of the modulatory influences of dynamic facial expressions between the amygdala and neocortical network (Figure 2). This revealed that modulation of dynamic facial expressions from the amygdala to the neocortical network best explained the differences between the ASD and TD groups (Figure 2)

Summary

Introduction

Autism spectrum disorder (ASD) is a neurodevelopmental condition associated with atypicalities in reciprocal social interaction [1]. The neurocognitive mechanisms underlying the social atypicalities of ASD remain elusive. Psychological studies have shown that various types of social cognitive processes are atypical in individuals with ASD compared with those of typically developing (TD) individuals; these atypicalities include emotional, perceptual, cognitive, and motor processing [14]. In ASD groups, functional neuroimaging studies revealed atypical brain activity associated with processing of social stimuli in multiple brain regions, including the amygdala, fusiform gyrus, superior temporal sulcus, and Neurocognitive Mechanisms of Autism inferior frontal gyrus [15,16,17].

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