Cerebral correlates of anticipated fear: a PET study of specific phobia.

Cerebral correlates of anticipatory anxiety was studied in 14 women with specific snake or spider phobia, and in 6 nonphobic controls. Videofilms with neutral scenes were shown during positron emission tomographic measurements of regional cerebral blood flow (rCBF). The phobics, but not the controls, anticipated scenes with spiders or snakes to appear in the videofilms. This was reflected in higher anxiety ratings in the phobics. The primary visual cortex rCBF was lower in phobics than controls, while no rCBF differences were found in the other brain regions investigated. The results are suggested to indicate inhibition of corticogeniculate pathways, in turn representing a neurophysiological correlate of avoidant anticipatory coping.