Chapter 5 – Experimental fear 173 Figure 6. Pain ratings for the nocebo and control trials in the extinction phase, across all three groups. Numeric Rating Scale (NRS) pain ratings during nocebo and control trials illustrate the evocation of nocebo responses and time-course of extinction, for the Control-nocebo, High-pain, and High-threat groups. The dotted vertical line indicates the thermode moving point, after which pain ratings suddenly peak due to placing the thermode on a new location on the arm. During the entire extinction phase all pain stimuli were administered at the same intensity. It is visible that the High-pain group (red lines) consistently rated nocebo trials (thick lines) higher than control trials (thin lines), as compared to the other groups (green and orange lines). Nocebo responses mediated by fear To test whether the larger nocebo magnitude in the High-pain group compared to the Control group was mediated by fear, a mediation analysis was conducted using the causal steps approach suggested by Baron and Kenny 47 implemented in PROCESS 43,44. This method uses regression analyses to determine the relationship between the predictor
RkJQdWJsaXNoZXIy MTk4NDMw