Figure 2:

Study procedures: Session 1: After attaining informed consent, participants were trained to use pain intensity and unpleasantness visual analog scale (VAS) in response to noxious heat stimulation (psychophysical training). The experimental Heat series included ten, 10 second plateaus of 49°C interleaved with 14 seconds 35°C stimulation applied to the back of the right calf. Participants were instructed to keep their eyes closed and rest in response to, two heat series. VAS ratings were collected after each respective heat series. After two heat series, participants were instructed to “sit quietly for 10 minutes” to control for the time spent initiating meditation in Session 6. After this 10-minute period, participants were administered two more heat series and VAS ratings were collected afterward. Participants were then randomized to a four-session (20 minutes/session) mindfulness meditation or a control group that listened to the Natural History of Selborne across four, 20 minutes sessions. After successful completion of their respective regimens (Session 2–5), participants reported to the MRI center for post-intervention functional MRI sessions. Session 6: After being positioned in the scanner, we administered two Heat series while participants rested with their eyes closed during fMRI acquisition. VAS ratings were collected after each respective heat series. Before anatomical acquisition, we instructed the members of the mindfulness group to “begin meditating and to continue until the end of the experiment.” The control group was instructed to “keep eyes closed”. After 10 minutes elapsed, we administered two more Heat series during functional acquisition and collected pain ratings after each respective series.