In addition, we conducted an exploratory regression analysis to examine whether endogenous pain intensity was related to intrinsic striatum functional connectivity, when considering the cLBP participants alone. We define the scanning period during which patients’ low back pain ratings are lower as the low pain (LP) condition and the scanning period during which patients’ low back pain ratings are higher as the high pain (HP) condition. Endogenous pain intensity was defined as the average self-reported pain rating immediately before and after resting state fMRI scanning. We further extracted the peak z value from the significant cluster resulting of each participant’s rsFC z score map. Within the LP and HP group, correlation analyses were computed
