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Theory of Mind in Autism Spectrum Conditions: a task-based neuroimaging approach

Poster A48 in Poster Session A, Thursday, October 6, 10:15 am - 12:00 pm EDT, Millennium Hall

Margot Mangnus¹, Saskia B.J. Koch¹, Miriam Greidanus Romaneli¹, Kexin Cai¹, Franziska Goltz¹, Peter Hagoort¹, Ivan Toni¹, Arjen Stolk^1,2, Jana Bašnáková¹; ¹Radboud University, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, ²Dartmouth College, Hanover, NH, United States

One of the leading hypotheses about the communicative difficulties in autism attributes these difficulties to an impairment in theory of mind (ToM), the ability to understand emotions, beliefs and desires of others (Baron-Cohen et al., 1985). The hypothesis is that impaired ToM abilities might hinder pragmatic interpretation, which requires taking the intentions of a speaker into account (Sperber & Wilson, 2002). However, this assumption has been recently questioned, as autistic people have been shown to perform above chance on pragmatic tasks that theoretically require understanding other people’s mental states, such as irony comprehension (e.g. Chevalier et al., 2011). We test the possibility that autistic individuals process mental states differently than neurotypical individuals by measuring fMRI activity and pupil dilation evoked by an animated movie. This movie was designed to induce mental state inferences, and is known to engage the ToM network in neurotypical individuals (Jacoby et al., 2016; Schurz et al., 2014; Paunov et al., 2019). 41 neurotypical adults and 46 adults diagnosed with Autism Spectrum Disorder matched on verbal IQ watched the six-minute movie in the MRI-scanner. They received instructions to simply watch the movie without any additional objective. Afterwards, we administered a questionnaire assessing their understanding of the plot and key emotional and mental state events. The fMRI analysis contrasted movie sequences previously linked to mental state inferences, emotional processing, and physical events (Jacoby et al., 2016; Paunov et al., 2019). Correlation between time-courses of participants’ pupil diameter during the entire movie (Nastase et al., 2019) was used to identify epochs with between-group differences in similarity of pupil responses. We considered epochs with a duration of 1 second and shorter to represent discrete events, in which primarily single actions of characters take place, and epochs of 5 seconds or longer to represent higher-level events, in which scenes and narrative-building take place. Preliminary results show that movie sequences linked to mental state inferences, as compared to physical events, activate core ToM brain regions (bilateral precuneus, angular gyrus and dmPFC) across both groups to a similar extent. In addition, neurotypical and autistic participants show similar understanding in their verbal descriptions of the movie plot and key events. Moreover, exploratory analyses of pupil size show that movie epochs of the short timescale in which discrete events happen to the characters on screen evoked weaker inter-participant correlation in pupil diameter in the autistic than in the neurotypical group. No such between-group differences were found in epochs at the longer, higher-level time scale. Neurotypical and autistic participants do not show differences on average in ToM processing in a nonverbal movie localizer. This finding corresponds with a large-scale study using a comparable ToM task in the same populations (Moessnang et al., 2020). We plan to use Bayesian inference to affirm this lack of between-group difference in brain activation. Lastly, the difference in synchronicity of processing in pupil size between the two groups might be a sign that autistic people’s processing of emotional expressions or physical actions could be distinctive in more subtle ways.

Topic Areas: Meaning: Discourse and Pragmatics, Disorders: Developmental