Sympathetic responding to unconditioned stimuli predicts subsequent threat expectancy, orienting, and visuocortical bias in human aversive Pavlovian conditioning.

Threat expectancy is the ability to predict an aversive outcome. What is not known is the influence of initial threat responding on the acquisition of verbal, attentional and perceptual biases towards conditioned threat cues. This study evaluated the extent to which initial unconditioned stimulus (UCS) responding was related to trial-by-trial self-reported expectancy, sensory processing (visuocortical EEG) and orienting (heart rate deceleration) to threat cues during extinction learning. Participants (n = 38) viewed oriented Gabor gratings, associated with the presence (CS+) or absence (CS-) of a 96 dB white noise (UCS), flickering at 12 Hz to elicit steady state visually evoked potentials (ssVEPs). Multivariate multiple regression revealed greater initial UCS skin conductance responding to predict extinction responding: enhanced visuocortical discrimination, greater heart rate deceleration to CS+, and greater threat expectancy endorsements. These results suggest that the motivational intensity of initial threat reactivity (sympathetic UCS responding) drives learning-induced defensive dispositions across multiple response systems.