Neural Correlates of Social Perception in Children with Autism: Local versus Global Preferences.

The Weak Central Coherence account of autism spectrum disorders posits that individuals with ASD utilize a detail-oriented information processing bias. While this local bias is helpful in visual search tasks, ASD individuals falter in social cognition tasks where coherence is advantageous. The present study examined the neural correlates of Weak Central Coherence in ASD during visual and social processing. Fifteen ASD and sixteen typically developing children/adolescents completed a social/visual information processing task in an fMRI scanner. The stimuli consisted of human characters, composed of geometrical shapes, displaying different emotions. In the locally oriented Shape condition, participants indicated whether a given shape was present in a figure. In the Emotion condition, participants identified the emotion conveyed by the character in the figure at the global level. Whole-brain within- and between-group activation and seed-to-voxel functional connectivity analyses were conducted in SPM12 and the CONN toolbox. The ASD group was significantly faster in shape identification, but less accurate in emotion identification. The TD group showed significantly increased areas of activity over the ASD group in the Shape task in regions associated with executive control, such as the medial prefrontal cortex and middle frontal gyrus, suggesting increased interference from the global/social information. During the Emotion condition, the ASD group showed decreased connectivity between frontal and posterior regions and between body perception and motor networks, suggesting a possible difference in mirroring. The findings suggest that social cognitive factors, not visual processing biases, underlie the observed behavioral differences.

The impact of atypical sensory processing on social impairments in autism spectrum disorder.

Altered sensory processing has been an important feature of the clinical descriptions of autism spectrum disorder (ASD). There is evidence that sensory dysregulation arises early in the progression of ASD and impacts social functioning. This paper reviews behavioral and neurobiological evidence that describes how sensory deficits across multiple modalities (vision, hearing, touch, olfaction, gustation, and multisensory integration) could impact social functions in ASD. Theoretical models of ASD and their implications for the relationship between sensory and social functioning are discussed. Furthermore, neural differences in anatomy, function, and connectivity of different regions underlying sensory and social processing are also discussed. We conclude that there are multiple mechanisms through which early sensory dysregulation in ASD could cascade into social deficits across development. Future research is needed to clarify these mechanisms, and specific focus should be given to distinguish between deficits in primary sensory processing and altered top-down attentional and cognitive processes.

Hemispheric differences in language processing in autism spectrum disorders: A meta-analysis of neuroimaging studies.

Language impairments, a hallmark feature of autism spectrum disorders (ASD), have been related to neuroanatomical and functional abnormalities. Abnormal lateralization of the functional language network, increased reliance on visual processing areas, and increased posterior brain activation have all been reported in ASD and proposed as explanatory models of language difficulties. Nevertheless, inconsistent findings across studies have prevented a comprehensive characterization of the functional language network in ASD. The aim of this study was to quantify common and consistent patterns of brain activation during language processing in ASD and typically developing control (TD) participants using a meta-analytic approach. Activation likelihood estimation (ALE) meta-analysis was used to examine 22 previously published functional Magnetic Resonance Imaging (fMRI)/positron emission tomography studies of language processing (ASD: N = 328; TD: N = 324). Tasks included in this study addressed semantic processing, sentence comprehension, processing figurative language, and speech production. Within-group analysis showed largely overlapping patterns of language-related activation in ASD and TD groups. However, the ASD participants, relative to TD participants, showed: (1) more right hemisphere activity in core language areas (i.e., superior temporal gyrus and inferior frontal gyrus), particularly in tasks where they had poorer performance accuracy; (2) bilateral MTG hypo-activation across many different paradigms; and (3) increased activation of the left lingual gyrus in tasks where they had intact performance. These findings show that the hypotheses reviewed here address the neural and cognitive aspects of language difficulties in ASD across all tasks only in a limited way. Instead, our findings suggest the nuances of language and brain in ASD in terms of its context-dependency. Autism Res 2016, 9: 1046-1057. © 2016 International Society for Autism Research, Wiley Periodicals, Inc.

Language and motor cortex response to comprehending accidental and intentional action sentences.

Understanding the meaning of others' actions involves mentally simulating those actions by oneself. Embodied theories of language espouse a prominent role for motor simulation in reading comprehension, especially when words, sentences, or narratives portray everyday actions. Inherent in these actions is the level of agency of the actor. Motor cortex activity in response to processing action verbs has been relatively well-established. What has been less explored, however, are: (1) the neural bases of determining whether an action is intentional or accidental (agency); and (2) whether agency influences level of motor simulation. This functional MRI study investigated how language and motor areas of the brain respond to sentences depicting intentional versus accidental action. 25 healthy adults read a series of sentences in the MRI scanner and determined whether the actions described were accidental or intentional. The main results include: (1) left hemisphere language areas (left inferior frontal gyrus, LIFG; left superior temporal gyrus, LSTG), premotor cortex (PM), and presupplementary motor area (pSMA) were strongly activated by both sentence types; (2) processing accidental action, relative to intentional action, elicited greater activity in LIFG, medial prefrontal cortex (MPFC), and left amygdala; no statistically significant activity was found in the opposite contrast; and (3) greater percent signal change was observed in LIFG while processing accidental action and in right precentral gyrus for intentional action. The results of this study support language and motor region involvement in action sentence comprehension in accordance with embodiment theories. Additionally, it provides new insight into the linguistic, integrative, and emotional demands of comprehending accidental action, its underlying neural circuitry, and its relationship to intentionality bias: the predisposition to ascribe purpose to action.