Neural correlates of moral reasoning in autism spectrum disorder

In our study, we tried to clarify whether patients with autism spectrum disorder (ASD) reveal different moral decision patterns as compared to healthy subjects and whether common social interaction difficulties in ASD are reflected in altered brain activation during different aspects of moral reasoning. 28 patients with high-functioning ASD and 28 healthy subjects matched for gender, age and education took part in an event-related functional magnetic resonance imaging study. Participants were confronted with textual dilemma situations followed by proposed solutions to which they could agree or disagree. On a neural level, moral decision making was associated with activation in anterior medial prefrontal regions, the temporo-parietal junction and the precuneus for both groups. However, while patients and healthy controls did not exhibit significant behavioral differences, ASD patients showed decreased activation in limbic regions, particularly the amygdala, as well as increased activation in the anterior and the posterior cingulate gyrus during moral reasoning. Alterations of brain activation in patients might thus indicate specific impairments in empathy. However, activation increases in brain regions associated with the 'default mode network' and self-referential cognition also provide evidence for an altered way of patients' cerebral processing with regard to decision making based on social information.