Neurocognitive mechanisms underlying identification of environmental risks.

Environmental risks threaten a large population and are more dreadful than personal risks that bring physical or health problems to individuals. To assess the neurocognitive processes involved in environmental risk identification, we recorded brain activities, using event-related potential (ERP) and functional magnetic resonance imaging (fMRI), from human adults while they identified risky and safe environmental and personal events depicted in words. We found that, relative to safe environmental events, the identification of risky environmental events induced larger amplitudes of an early positive ERP component at 180-260ms over the frontal area (P200) and of a late positive wave at 420-660ms over the central-parietal area (LPP). fMRI results showed that the identification of environmental risks was associated with increased activations in the ventral anterior cingulate cortex (vACC) and posterior cingulate cortex (PCC). The amplitudes of the LPP/P200 and the PCC activity positively correlated with subjective ratings of risk degree of and emotional responses to the risky environmental events. However, the identification of personal risks induced positive shift of ERPs at 280-320ms over the frontal and parietal areas and increased activity in the left inferior and medial prefrontal cortex. Our findings suggest that identification of dreadful environmental risks is subserved by an early detection in vACC and a late retrieval of emotional experiences in PCC.