Diminished Superior Temporal Sulcus Response to Communicative Intent in Children with ASD

Background: Processing others’ goals and intentions is critical for engaging in and understanding communicative interactions. The neural mechanisms for processing communicative intent are not well known, and may be disrupted in children with autism spectrum disorder (ASD) who show deficits in social and communicative abilities. The posterior superior temporal sulcus (pSTS) is one brain region that has been implicated in intention understanding. Specifically, Vander Wyk and colleagues (2009) reported that the pSTS responds to unexpected or incongruent actions (i.e., when an actor reacts negatively to an object and then reaches for it). The pSTS seems to be involved in encoding goals or intentions rather than simply responding to unexpected events, since it responds more to failed actions than successful actions (Shultz et al., 2010). Researchers have reported pSTS dysfunction in ASD using a variety of tasks including biological motion perception (Kaiser et al., 2010).

Objectives: We adapted a paradigm from infant research to examine the neural mechanisms supporting the assessment of communicative intent and evaluation of communicative interaction outcomes in typically developing (TD) adults, and children with and without ASD.

Methods: During a functional magnetic resonance imaging scan, groups of TD adults, TD children, and children with ASD viewed a series of 10-second videos. In each video, an actor reached for one of two unfamiliar objects to show a preference for that object (Target object). In the next scene, the actor’s arms were blocked from reaching the objects and a new actor was present who had full access to the objects. The first actor looked at the second and said a nonsense word, and the second actor picked up the Target or Non-target object and extended it toward the first actor.

Infants who saw similar events looked longer (suggesting surprise) when the second actor handed over the Non-target rather than the Target object (Martin, Onishi, & Vouloumanos, under review). We hypothesized that TD participants, but not those with ASD, would exhibit a differential pSTS response to successful (Target) and unsuccessful (Non-target) communicative interactions.

Results: Since we were interested in whether the pSTS responds to a mismatch between communicative intentions and outcomes in the same way as it responds to a mismatch between an individual’s intentions and subsequent behavior, we used a pSTS region of interest in our analysis (Vander Wyk et al., 2009). Preliminary results suggest that TD adults and children exhibit a greater pSTS response to Non-target than Target outcomes, while children with ASD do not.

Conclusions: Children with ASD seem to exhibit disruptions in brain mechanisms for processing intentions and outcomes in communicative interactions. In particular, the current findings highlight dysfunction in the pSTS in autism, which may contribute to or reflect some of the core social deficits of the disorder. Here we have focused on a pSTS ROI approach but whole brain contrasts will be implemented with larger samples. In addition, further work will investigate the behavioral responses (e.g. eyetracking) of children with ASD to communicative scenarios to further illuminate the nature of the processing differences.