Objectives: To characterize reward circuitry function in autism with fMRI.
Methods: In a series of fMRI studies we examined fMRI responses to social rewards (smiling faces), non-social rewards (money) and individual-specific rewards based on each subject’s special interest. We also examined the extent to which subjects learned implicit but deterministic associations with reward mediation. FMRI scanning was conducted on a Siemens 3Tesla Trio system, using an implicit learning paradigm based on Knowlton’s Probabilistic Classification task. Subjects were shown a series of fractal-like images and pressed a button to indicate whether each item belonged to “1” or “2”. In Exp. 1 (16 ASD, 16 TD; VanZeeland et al, 2010), subjects received information only feedback (correct or incorrect), feedback with a social reward (smiling face vs. pouting face), or monetary feedback (money cure or crossed-out money icon). In Exp 2 (D. Shirinyan, IMFAR 2011), subjects (19TD, 17ASD) were first questioned about their specific interests; a picture of their desired reward (or a crossed out picture of it) and a control picture from another subject’s reward were used to provide feedback
Results: In comparison to typically developing children, those with ASD showed reduced responses in the VS to social rewards, and a non-significant reduction for monetary rewards. In contrast, children with ASD showed enhanced VS responses to rewards associated with their specific interest compared to TD children.
Conclusions: These results present a more complex picture of reward circuitry dysfunction in autism, suggesting a model of restricted, item-specific reward responsiveness that may be excessive, while responses to other rewards, including primary reinforcers, is reduced. This pattern is consistent with a more general deficit in information processing in autism characterized by increased local processing and decreased implicit/extraneous of background processing, affecting reward as well as other systems.