Cerebral blood flow during anxiety provocation

Abstract

It has been suggested that traumatic reactions result from the failure to integrate the trauma with existing cognitive schemata, whereas phobias represent biologically influenced adaptation patterns. This implies that central nervous system (CNS) organization of traumatic reactions may differ from that of phobic reactions. In this article, we review our previously published work on anxiety and regional cerebral blood flow (rCBF). By using positron emission tomography and [(15)O]-butanol, relative rCBF was determined in 14 subjects with simple animal phobias exposed to visual phobogenic stimuli and in 6 bank officials exposed to a video showing an armed bank robbery that they recently witnessed. Subjective and physiologic indices of fear and anxiety were elevated by the activation condition in both groups. Phobic stimulation elevated rCBF bilaterally in the secondary visual cortex compared with neutral stimulation but reduced rCBF in the hippocampus and in the prefrontal, orbitofrontal, temporopolar, and posterior cingulate cortex. Compared with neutral stimulation, video of a robbery increased rCBF bilaterally in the primary and secondary visual cortex, the posterior cingulate, and the left orbitofrontal cortex. Decreased rCBF was evident in Broca's area, the left angular gyrus, the left operculum, and the secondary somatosensory cortex. Hence, visually induced fear and anxiety are associated with alterations in limbic, paralimbic, and cortical brain regions that are of relevance for cognition and affect.