Chapter 7 – Pharmacological fMRI 227 phases, the activation of sham electrical stimulation was paired to covertly increased pain stimulation during nocebo trials. Pharmacological manipulation A single dose of DCS was administered at 80mg for all participants in the DCS group. The LUMC pharmacy prepared DCS (powder form) into capsules, as well as placebo capsules of identical appearance containing the inert agent microcrystalline cellulose. Because plasma concentrations were expected to peak between 1 and 3 hours after DCS administration 39,40, participants ingested the capsule 2 hours before entering the MRI scanner to undergo the main learning paradigm. Measures Pain Throughout the experiment, participants were provided with a 6-second window to rate their pain on a sliding scale representing the pain NRS, following each pain stimulation. A message, presented on the computer monitor 2 seconds after the pain stimulus returned to skin temperature, prompted the pain rating to be given by use of a keyboard in the screening part and button boxes in the MRI session. Learning To assess learning rates before and after the administration of DCS, participants completed the Wechsler Memory Scale–Fourth Edition
RkJQdWJsaXNoZXIy MTk4NDMw