Mia Thomaidou

Chapter 7 – Pharmacological fMRI 229 were used to measure psychological characteristics: a short version of the State-Trait Anxiety Inventory, State version (STAI-S-s) 43,44, the State-Trait Anxiety Inventory, Trait version (STAI-T) 44, the Pain Catastrophizing Scale (PCS) 45 which assesses catastrophizing thoughts or worrying relating to pain 46, and the Body Vigilance Scale (BVS) 47 measuring vigilance about bodily sensations. Total scores were used. Participants also completed an exit questionnaire at the end of the experiment, containing manipulation checks and questions about their participation and side effects. The questions were: “did you believe the information you received in this study”, “how much did you worry about what the experimenter thought of you or changing your responses to please them”, “were you focused on the pain stimulations during the study”, and “did you notice the association between the electrical stimuli and pain aggravation”. Questions were rated on a 0-10 NRS from “not at all” to “very much”. All questionnaires were displayed on a computer monitor via web-based survey software (Qualtrics, Provo, Utah, USA). Study procedures During the screening part (see Figure 1), participants signed an informed consent form and completed the health, psychiatric, and MRI screening for inclusion in the study. Sensory and pain threshold levels were then tested, and pain stimuli were calibrated for each participant. The electrodes were then attached to the hand and arm and the short mock calibration of the sham electrical stimulation took place. Preconditioning was then completed. During the MRI part, participants first completed the WMS–IV and then received the oral pharmacological administration. During a 2-hour waiting time for DCS to take effect, participants had a small, standardized meal, completed the psychological questionnaires, and prepared to enter the MRI scanner. Then, participants entered the scanner, completed a structural scan, and

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