Figure 3.

Maps of BOLD responses to pain in 9 fibromyalgia (FM) patients and nine pain-free controls (CO). (A) BOLD response by group and condition (EX = exercise; QR = quiet rest); (B) significant group by condition interaction in BOLD responses in the left dorsolateral prefrontal cortex (DLPFC). Color represents the β coefficient (% signal change ranging from −1% to 1%) and opacity represents t-statistic, with full opacity at a voxelwise t corresponding to p < 0.01. The significant cluster at α<0.05 (corresponding to a cluster size threshold of 17 voxels) is outlined in white. Analyses were performed at 4 mm × 4 mm × 4 mm resolution using a mask of regions determined a priori from the hypotheses, which is highlighted in the background of image B; (C) Violin plot illustrating the simple main effects underlying the interaction in the DLPFC. Each point represents the average %∆BOLD in the indicated cluster during one run, such that each subject is represented by three connected points. Shadows connecting points between violin plots indicate data from the same individual during each condition (EX & QR). Note that the region from which these points are drawn was chosen because there is a significant interaction between group and condition; the plot is intended to further clarify the interaction.