Self-Other Differentiation In Cortical Midline Structures Is Atypical In Children and Adolescents with High-Functioning ASD

Background: Autism Spectrum Disorder (ASD) is being increasingly characterized not only by aberrant patterns of interaction with others, but atypical development of the self. Research suggests children with ASD show impairments in autobiographical memory and significantly less rich social self-concepts that incorporate less social-comparative or interpersonal contextual information. Recent social neuroscience studies have documented differences in brain functioning that may underlie these atypical self-appraisals in ASD. Self-evaluative processing is commonly associated with activity in cortical midline structures (CMS), including medial prefrontal cortex (mPFC) and medial posterior parietal cortex (mPPC), in neurotypical (NT) children, adolescents, and adults. However, in adults with ASD there appears to be a lack of differentiation between self and other in mPFC (Lombardo et al., 2010). It is as yet unknown how the neural foundations of self-evaluative processing differ between NT and ASD groups earlier in development, but such information is critical to understanding and ultimately intervening to ameliorate the consequences of atypical self-development in ASD.  

Objectives: Explore self-other differentiation in CMS displayed by children and adolescents (NT vs. ASD) across two domains (social vs. academic competence).

Methods: Participants were 18 youth with high-functioning ASD aged 8.8-17.8 (1 female, diagnoses confirmed via ADI-R/ADOS-G) and 18 age-, gender-, and IQ-matched NT controls. During fMRI, participants reported whether phrases describing social or academic attributes and abilities described themselves or a familiar, fictional young character (i.e., Harry Potter), in counterbalanced order. Data were preprocessed and analyzed using FSL, SPM, and MarsBaR, including: i) brain extraction, realignment, coregistration, normalization, and spatial smoothing, ii) constructing first-level (fixed effects) and second-level (random-effects) models, and iii) interrogating regions of interest.

Results: Replicating previous fMRI studies, NT youth demonstrated greater engagement of CMS when making self-evalutions vs. other-evaluations. However, youth with ASD did not show a comparable effect. Direct comparisons between groups showed that, relative to youth with ASD, NT youth exhibited significantly more anterior rostral and ventral mPFC activity, as well as more activity in dorsal anterior cingulate cortex  (during self>other). Meanwhile, relative to NT youth, youth with ASD demonstrated significantly more activity in dorsal PFC (both medial and lateral aspects) during the opposite contrast (other>self), as well as more activity in bilateral anterior insula. However, when comparing self-evaluations in the social and academic domain directly, both NT youth and youth with ASD engaged mPFC relatively more during the former than the latter.

Conclusions: The results of this initial study exploring the neural correlates of self/other appraisals in youth with ASD suggest that similar to adults with ASD, they do not engage mPFC more during self-evaluations than other-evaluations. Failure to preferentially engage mPFC during self-evaluations in youth with ASD may indicate a lack of self-other differentiation, already hypothesized to be one factor contributing to atypical self-development. However, youth with ASD may show a more normative response when the task encourages them to make self-evaluations in the social than academic domain. This identifies potential targets for interventions to enrich self/other perception in youth with ASD.