Figure 1.

Experimental design chart outlining the steps in a single experimental block comprising four cold-pressor test (CPT) submersions. Each block consisted of three stages: pre-conditioning, with an initial CPT submersion (CPT1); conditioning, induced by application of placebo cream prior to a second CPT submersion (CPT2 where temperature was raised surreptitiously by 5 °C); and post-conditioning, with two final CPT conditions (CPT3 and CPT4 without and with prior application of placebo cream, respectively). Note that each CPT submersion was preceded by resting state eyes open (EO) and eyes closed (EO) conditions for baseline EEG recordings and followed by submersion of the hand in warm water - hand warming (HW) time.