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

Abstract

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 prior studies that examined neural processes underlying anxiety, such as hypersensitivity to unpredictable threat. We investigated the association between trait worry (as a key component of anxious apprehension), anxious arousal, and the neural processing of anticipated threat. From a large online community sample (N = 1,603), we invited 136 participants with converging and diverging worry and anxious arousal profiles into the laboratory. 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. Worry was associated with increased startle responses to unpredictable threat and increased attentional allocation (P3) to startle probes in predictable threat anticipation. Anxious arousal was associated with increased startle and N1 in unpredictable threat anticipation. These results suggest that trait variations in the anxiety dimensions shape the dynamics of neural processing of threat. Specifically, trait worry seems to simultaneously increase automatic defensive preparation during unpredictable threat and increase attentional responding to threat-irrelevant stimuli during predictable threat anticipation. The current study highlights the utility of anxiety dimensions to understand how physiological responses during threat anticipation are altered in anxiety and supports that worry is associated with hypersensitivity to unpredictable, aversive contexts.

Keywords: Anxiety dimensions; Anxious apprehension; Event-related potentials; NPU-threat test; Startle reflex; Threat anticipation; Uncertainty; Unpredictability.

Fig. 1

Scatter plots and density distribution of PSWQ and MASQ-AA scores. Note. From an online screening sample (N = 1,603), we invited N = 136 participants to the laboratory to perform the NPU-threat test while we collected psychophysiological data. The recruitment was based on the median of the questionnaires operationalizing the anxiety dimensions, i.e., Penn State Worry Questionnaire (PSWQ, Mdn = 47, dashed vertical line) and the anxious arousal subscale of the Mood and Anxiety Symptom Questionnaire (MASQ-AA, Mdn = 24, dashed horizontal line). To obtain equal sample sizes in each group of the median based 2 (PSWQ: high vs. low) × 2 (MASQ-AA: high vs. low) design, we oversampled participants in whom one dimension was more pronounced than the other

Fig. 2

NPU-threat test. Note. In the neutral condition, the countdown was never followed by the aversive stimulus (100 dB, auditory scream paired with the picture of a fearful face, image 01F from NimStim Tottenham et al. (2009)). In the predictable condition, the aversive stimulus occurred every time the countdown reached “1”. In the unpredictable condition, the aversive stimulus could occur at any time during the countdown or the interstimulus interval

Fig. 3

Participant’s mean startle responses across the conditions and cues. Note. Raw startle amplitudes were range corrected within participants to control for individual differences in absolute blink magnitude. Each amplitude was divided by the maximal amplitude of the participant, so that all amplitudes lie between 0 and 1

Fig. 4

Startle slopes of the Penn-State Worry Questionnaire (PSWQ) and the anxious arousal subscale of the Mood and Anxiety Symptom Questionnaire (MASQ-AA) across the experimental conditions of the NPU-threat test. Note. Data are collapsed across cues (interstimulus interval, countdown), because no modulation by cue was observed. The shaded area indicates a 95% confidence interval of the estimated slope. Raw startle amplitudes were range corrected within participants to control for individual differences in absolute blink magnitude. Each amplitude was divided by the maximal amplitude of the participants, so that all amplitudes lie between 0 and 1

Fig. 5

Grand averages across experimental conditions (left) and head maps (right) of the event related potentials N1 (top) and P3 (bottom). Note. The signal is locked to startle probes and is collapsed for the grand averages (left) for illustration across cues of the NPU-threat test. The time windows for quantification of N1 (±25 ms area around the individual peak at FCz; white dot; ca. 120-170 ms) and P3 (mean activity 300–370 ms at Pz; white dot) are indicated by shaded grey bars. The shaded area around the mean signal depicts ± standard error of the distribution at each ms. The head maps (right) show the grand average signal collapsed across the conditions and cues of the NPU-Threat test

Fig. 6

Jitter plot, box plot and density plots of the N1 (top) and P3 (bottom) across the conditions of the NPU-threat test. Note. Data are collapsed across the cues (countdown and interstimulus interval)

Fig. 7

Averages (A) and slopes (B) per condition of the NPU-threat test by PSWQ. Note. A. Averages of P3 across the conditions of the NPU-threat test for participants below and above the median split (47, color-coded) of the Penn-State Worry Questionnaire (PSWQ). Shaded areas around the signal depict the standard error at each ms; the shaded grey areas show the time window for quantification of the P3 (mean activity 300–370 ms). The dashed line indicates the onset of the startle probe. B. Slopes of the PSWQ and P3 across the experimental conditions of the NPU-threat test. The shaded area around the slope depicts the 95% confidence interval of the slope estimate. Data are collapsed across cues (countdown, interstimulus interval)