An imaging study of Theory of Mind: How is the ‘network' affected in ASD?

Background: Theory of Mind (ToM) is a complex cognitive function underlying social interaction and reasoning. Several distinct brain regions have been implicated in ToM, including the medial prefrontal cortex, superior temporal regions and the temporoparietal junction. The interaction between these regions is likely to be critical for intact ToM, effectively forming a network of interconnected regions similar to the ‘social brain’ (Brothers, 1990). Impaired ToM is a core deficit in autism spectrum disorder (ASD), a neurodevelopmental disorder associated with aberrant connectivity. Furthermore, reduced functional and structural connectivity has been reported in individuals with ASD between regions typically associated with ToM (Barnea-Goraly et al., 2004; Castelli et al., 2002).

Objectives: To establish whether there is a ToM ‘network’ in typically developing (TD) individuals, and to determine how the purported network is affected in ASD.

Methods: Data from five males with ASD and five TD males will be reported. ToM will be assessed using a comic strip paradigm based on the task devised by Sarfati et al. (1997). DTI data will be acquired and tract-based spatial statistics conducted to assess white matter (WM) integrity. Finally, probabilistic tractography will be initiated from seed masks placed within WM tracts running between cortical regions associated with ToM in controls.

Results: The behavioural, functional imaging and diffusion data from 5 adult males with ASD and 5 TD adult males will be presented.

Conclusions: It is anticipated that individuals with ASD will exhibit different patterns of ToM-related activity compared with TD controls. Furthermore, it is predicted that individuals with ASD will exhibit decreased WM integrity over the whole brain, and regionally in WM regions connections areas associated with ToM in TD individuals. Such findings would support the theory that aberrant connectivity may partially underlie the cognitive profile of ASD.