Fig. 2
From: Effects of chiropractic spinal manipulation on laser-evoked pain and brain activity
Experimental paradigm. Participants received four blocks of 20 laser stimuli for a total of 80 stimuli. After each block, participants were instructed to rate pain verbally. Between block 2 and 3, participants received either no intervention, the placebo intervention, spinal manipulation at T4 (SM-T4) or spinal manipulation at T8 (SM-T8). Laser-evoked pain and brain activity were averaged over 40 stimuli and were compared before and after the intervention (PRE vs POST conditions)