A functional anatomy of anticipatory anxiety

Anticipatory anxiety is a complex combination of a future-oriented cognitiv e state, negative affect, and autonomic arousal. A dual-task paradigm of an ticipation of electric shocks and a motor-learning task was used to examine the changes in neural patterns of activation associated with modulation of the cognitive state in anxiety by a distracting motor task. We used positr on emission tomography (PET) and O-15-water to measure regional cerebral bl ood how (rcbf) in 10 healthy male volunteers. A 2 x 2 factorial design(shoc k vs no shock) x (low vs high distraction) was used with three scans per co ndition. Twelve PET scans were performed on each subject, In six of these s cans, subjects were given electric shocks. In all scans, subjects also simu ltaneously performed a motor repetition (low distraction) or learning (high distraction) task. Galvanic skin conductance (GSR), Spielberger State and Trait Anxiety Inventory (STAI), and self-report data were also collected. I n comparisons between the shock and no-shock conditions, the main finding w as of increased rcbf in the left insula (-38,8,8) (z = 4.85, P < 0.05 corre cted) and a homologous area in the right insula at a lower threshold(z = 3. 20, P = 0.001 uncorrected). Other areas activated were the right superior t emporal sulcus, left fusiform, and left anterior cingulate. Using the STAI- state scores as a covariate of interest, significant correlations with rCBF were seen in the left orbitofrontal cortex, left insula, and left anterior cingulate cortex. There was no significant distraction effect as measured by the STAI, self-report, GSR response or interactional analysis of the PET data. These findings support the role of paralimbic structures as neural s ubstrates of anticipatory anxiety. The failure to demonstrate behavioral an d neurophysiological changes with the distracter task may reflect the modes t increases in anxiety with the shock, the relatively simple distracter tas k, and small sample size. (C),1999 Academic Press.