Emotion-induced changes in human medial prefrontal cortex: II. During anticipatory anxiety

Regional cerebral blood flow (BF) was examined in the human medial prefront al cortex (MPFC) with positron emission tomography during anticipatory anxi ety. Transient anxiety was induced in normal subjects by having them antici pate a painful shock to the fingers of one hand. BF was decreased during an ticipatory anxiety, relative to an eyes-closed resting condition, in two re gions of the MPFC (Brodmann Areas 10/32 and 24/25). BF decreases in these a reas were inversely correlated with anxiety self rating, such that the leas t anxious subjects exhibited the largest BF reductions, whereas the most an xious subjects showed no significant BF reduction or a slight increase. BF changes in MPFC and in the midbrain were correlated with each other and wit h anxiety self rating. These results are consistent with the hypothesis tha t BF reductions in MPFC, previously observed in cognitive tasks, reflect a dynamic balance between focused attention and subject anxiety and may occur from a functionally active baseline or default state. The characterization of such relationships within the human brain enables new insights into the integration of cognition and emotion.