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. Author manuscript; available in PMC: 2016 Aug 1.
Published in final edited form as: Pain Med. 2015 Jun 25;16(8):1580–1588. doi: 10.1111/pme.12798

Figure 1.

Figure 1

Diagram of experimental protocol. The two testing blocks were separated by a 90-minute rest interval. The polarity of tDCS received during Block 1 was randomized and counterbalanced; the opposite polarity of tDCS was delivered during Block 2. Within each testing block, there was a seven-minute acclimation period to tDCS (see text) followed by the three experimental tasks: cold pressor, pressure algometer, and breath holding. The order in which the tasks were presented was randomized and counterbalanced. The “DVPRS” labels indicate when DVPRS pain ratings were obtained over the course of the experiment.