Neural Mechanism May Explain Variability of Social Ability in Autism

Vignesh Subramanian ’24

Figure 1: Development of the theory of mind begins at a young age. 

Autism spectrum disorder (ASD) is a neurodevelopmental disorder involving significant challenges with communication, behavior, and social skills. The range of conditions encompassed by the term is most often characterized by limited but intense interests, repetitive patterns of behavior, difficulty maintaining or regulating interactions with other people, and difficulty synchronizing facial expressions or motor movements with speech. It has long been believed that individuals with ASD struggle with impairments in theory of mind (ToM), their capacity to correctly perceive and attribute mental states, including emotions, desires, and beliefs to themselves and others. However, more recent studies have suggested that ToM impairments for individuals with ASD vary in severity, leading to uncertainty about the neural mechanism that underlies such deficits in their ability to take and understand perspectives. A study led by Dr. Libsack of Stony Brook University thus aimed to better characterize the relationship between ASD symptoms and ToM performance to understand the variability in the latter.

Researchers instructed 78 adolescents, including 48 with ASD, to view a series of ToM-focused vignettes simulating social scenes and then make a set of inferences about the involved characters’ mental states. The researchers concurrently took the subjects’ electroencephalographic (EEG) recordings to correlate conditional measures of brain activity known as event-related potentials (ERPs) with ToM accuracy. Researchers successfully elicited two ERPs: the late positive complex (LPC), which indexes the attention, recognition, and memory paradigm, and the late slow wave (LSW), which indexes the later reasoning behind attributions of mental states made. The subsequent ERP analysis revealed that verbal IQ correlated with overall behavioral task performance but not with ASD symptom severity between both measures, that older age correlated with smaller LPC, greater LSW, and greater ASD symptom severity, but not behavioral task performance, and that increased ASD symptoms correlated with poorer ToM performance. The ERP topographic maps further revealed that one of the two ERPs, LPC, demonstrated a significantly positive relationship with ToM performance and a negative association with ASD symptom severity.

Taken together, the findings provide the first known evidence that discrete neural indices can predict specific stages of ToM processing in ASD. Furthermore, the relative size of the LPC elicited in response to correct and incorrect ToM conditions substantiates this ERP’s ability to accurately represent cognitive metarepresentation. Such a finding suggests deficits in ToM reasoning occur in response to fading recollection of no longer visible image stimuli, and thus, during the relatively early, recognition-memory phase of the perception process. Future studies may parse more complex aspects of ToM reasoning and thus more firmly conceptualize the diagnostic boundaries of ASD. 

Works Cited:

[1] E. Libsack, et al., An Electrocortical Measure Associated With Metarepresentation Mediates the Relationship Between Autism Symptoms and Theory of Mind. Clinical Psychological Science 9, 1-16 (2021). doi: 10.1177/21677026211021975

[2] Image retrieved from: https://commons.wikimedia.org/wiki/File:Boy_with_Autism.jpg

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