Action Perception In Children with and without Autism Specturm Disorders

Background:

Individuals with autism spectrum disorders (ASD) exhibit deficits in using gaze spontaneously to understand and predict other people’s mental states and behaviors. Neuroscientists have begun to identify key brain regions involved in this aspect of social perception in typically developing adults (i.e., “the social brain”), and work has commenced on identifying dysfunction in ASD.

Objectives:

We tested the hypothesis that the brain circuitry involved in perceiving the intentions underlying other people’s actions develops abnormally in children with autism. We conducted a cross-sectional study of children with and without autism using a joint attention paradigm, while measuring activity using fMRI and concurrently tracking eye gaze inside and outside the scanner.

Methods:

Adapting a previously used joint-attention paradigm, participants viewed videos of an actress expressing either a positive or negative emotion towards one of two cups and subsequently grasping one of them. If the actress grasped the cup that has either received positive regard or had not received negative regard, the action was Congruent (i.e. the action would be expected based upon the previous expression); otherwise, the action was Incongruent. The experiment used an event-related design with participants viewing 16 trials of each condition (Positive/Congruent, Positive/Incongruent, Negative/Congruent, and Negative/Incongruent). Eye gaze was monitored using a custom-built eye tracking system inside the scanner and outside the magnet using a Tobii-T60. In both cases, visual stimuli are being partitioned into areas of interest (AOIs) corresponding the actress’s face and the targets of reach.

Results:

We plan to compare activation within regions of the posterior superior temporal sulcus (STS) to the Incongruent and Congruent trials. For the neuroimaging component of this study, we expect that the STS region and other brain regions previously shown to be engaged by joint attention paradigms will respond more strongly and exhibit greater functional connectivity for incongruent compared to congruent reaching conditions in typically developing children. In contrast, we predict that children with ASD will not exhibit this increased activity and functional connectivity. Since sensitivity to emotional expression is a skill that develops over childhood and supports social competence, we predict that both age and skill will correlate with the magnitude of this effect. Preliminary fMRI evidence from typically developing children (n= 32) and children with an ASD (n=5) is consistent with these hypotheses.

Conclusions:

Increased activation in regions processing joint attention is hypothesized to reflect the need to update representations based on the observation of actions that are inconsistent with expectations, a basic constituent of higher order social cognition. The lack of such activation in ASD may reflect a failure to link the actress’ actions to the expectations set up by the actress’ direction of gaze and positive or negative affectation. Higher-level social cognition deficits often noted in ASD, such as theory of mind, might actually result from disruption of a more basic ability, such as responses to bids for joint attention or responses to mutual versus averted gaze. Thus, these complex deficits might be culminations rather than starting points.