Don't worry, it won't be fine. Contributions of anxious apprehension and anxious arousal to startle responses and event-related potentials in threat anticipation

A widely shared framework suggests that anxiety maps onto two dimensions: Anxious apprehension and anxious arousal. Previous research linked individual differences in these dimensions to differential neural response patterns in neuropsychological, imaging, and physiological studies. Differential effects of the anxiety dimensions might contribute to inconsistencies in clinical and non-clinical studies that examine neural processes underlying anxiety such as hypersensitivity to unpredictable threat. The present study investigated associations between the anxiety dimensions and the neural processing of anticipated threat. From a large online sample (N = 1,603), we invited 136 non-clinical participants with converging and diverging anxious apprehension and anxious arousal profiles into the laboratory. The participants underwent the NPU-threat test with alternating phases of unpredictable threat, predictable threat, and safety, while physiological responses (startle reflex and startle probe locked event-related potential components N1 and P3) were recorded. Anxious apprehension predicted increased startle responses to unpredictable threat and increased attentional allocation (P3) to startle probes in predictable threat anticipation. Initial evidence emerged for anxious arousal predicting increased startle and N1 in unpredictable threat anticipation. These results suggest that trait variations in the anxiety dimensions likely shape the dynamics of neural processing of threat stimuli. Specifically, anxious apprehension seems to simultaneously increase automatic defensive preparation during unpredictable threat and increase attentional responding to threat-irrelevant stimuli during predictable threat anticipation. Individual differences in the anxiety dimensions might be reflected in altered physiological response patterns such that more pronounced symptom profiles in one dimension might be associated with hypersensitivity to unpredictable aversive contexts.