Short summary

Autism spectrum disorder (ASD) is pervasive developmental disorder involving various symptoms, including difficulties with social interaction. However the cognitive and neural mechanisms underlying these impairments are poorly understood. In this project, we aim to investigate the neural correlates of social interaction (operationalised by a social game) in ASD using fMRI in order to further the understanding of social difficulties in ASD.

Rationale

Autism Spectrum Disorder (ASD) comprises a spectrum of heterogeneous pervasive neurodevelopmental disorders characterised by problems in social interaction, communication, and repetitive or stereotypic behaviour and interests (Stigler et al., 2011; APA, 2013). More specifically, ASD patients show impairments in social behaviours such as lack of interest in social interactions and the emotional states of others, impairments in mentalisation and difficulties with social reciprocity (Barak and Feng, 2016; Bauminger et al., 2003; Baron-Cohen, 2000).

Social cognition has been the subject of numerous studies in ASD research (Baron- Cohen et al., 2001; Baron-Cohen and Belmonte, 2005), but a deep understanding of the neural mechanisms underlying difficulties with reading intentions of others and responding gestures during a social exchange in ASD is lacking. Hence, in order to identify new targets for effective interventions in ASD, a better understanding of the mechanisms underlying difficulties in these aspects of social cognition is required.

In this study, we will use the fMRI to study social decision-making in young boys (aged 12-17) with ASD and controls. For this purpose we will use a fairness game, which describes a range of paradigms based on game theory used to study reciprocity mechanisms (e.g. King-Casas et al., 2005; Rilling et al., 2002; Kirk et al., 2011; Montague et al., 2011). In one version of this game, called the multi-round Trust game, two players participate in a social exchange in which their decisions are based on what the players consider is fair. Performance on these fairness games has been proposed as a computational phenotype in ASD (Montague et al., 2012) and used as an experimental paradigm to assess social interaction in ASD and other psychiatric disorders (e.g. Gradin et al., 2015; Kishida et al., 2010; King-Casas and Chiu, 2012).

Using the above paradigm in combination with fMRI, the overall aims of the current study are:

1) To characterise abnormal behavioural and neural responses to social signals with ASD

2) To estimate individualised features of brain structure and function and investigate these structural and functional patterns as a function of age in order to identify the developmental trajectory of anomalous brain correlates of behaviour.

In terms of these aims, our hypotheses are:

a)  Individuals with ASD will exhibit anomalous cingulate cortex neural responses
that correlate with behavioural difficulties in inferring social agency

c)  Individuals with ASD will exhibit decreased striatal activation to positive social signals, a possibility consistent with the lack of 'reward' content of social interactions for these ASD subjects and deviating from prior
observations in normal subjects

d)  The hypothesized brain patterns described above will vary in strength as a function of age and thus provide heterogeneity of symptoms and subtypes of
the ASD cohort 

Description of the cohort

Boys diagnosed with autism spectrum disorder (or controls with no psychiatric diagnosis) aged 12-17 years

Data and biological material

fMRI data, behavioural data, clinical/neuropsychological data, questionnaires.

Publications associated with the project

Center for Neuroimage Analysis, University of Utah

• Tom Fletcher.