200 augmented pain to establish whether they are characterized by divergent EEG biomarker values. Finally, we explored the correlation between pain-related psychological questionnaires and measures of EEG. Nocebo manipulation check The magnitude of reported nocebo hyperalgesia was measured withinsubjects, and was defined as the difference in pain ratings for the first nocebo trial compared to the first control trial, during evocation. The first evocation trials were selected to answer the manipulation-check question of whether significant nocebo hyperalgesia was induced, as previous studies indicate the effect to be clearest in those trials 31,32. Behavioral data handling Behavioral data were analyzed by use of SPSS 23.0 (IBM Corp., Armonk, NY, USA). The threshold for significance was set at P < 0.05 and partial eta-squared (ηp 2) was computed as a measure of effect size, with ηp 2 of 0.01 considered small, 0.06 considered medium, and 0.14 considered a large effect size 33,34. To conduct repeated measures analysis of variance (ANOVA), the assumptions of normality and homogeneity of variances were checked. Computation of EEG biomarkers Spectral and temporal biomarkers were computed for all EEG recordings within three canonical frequency bands: alpha (8–13 Hz),
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