The neural basis of risk ratings: evidence from a functional magnetic resonance imaging (fMRI) study.

Research investigating risk perception suggests that not only the quantitative parameters used in technical risk assessment (i.e., frequency and severity of harm) but also 'qualitative' aspects such as the dread a hazard provokes or its controllability influence risk judgments. It remains to be elucidated, however, which neural mechanism underlie risk ratings in healthy subjects. Using fMRI to detect changes in neural activity we compared the neural activations elicited by risk ratings with those elicited by a letter detection task performed on the same stimuli. The latter task served to control for basic stimulus processing, response selection and button-pressing during task performance. Risk ratings differentially activated the medial prefrontal cortex, the inferior frontal gyrus, the cerebellum (P<0.05, FWE corrected, whole brain approach), and in an additional ROI analysis the amygdala (P<0.05, FWE corrected). Of these structures, particularly the amygdala and the prefrontal cortex have been previously associated with decisions about affective interference. Furthermore our data suggest both, similarities and differences between the neural correlates of risk ratings and risk taking as involved, for e.g., in gambling tasks.