Fig 9.

Increased alpha power in the ascending nociceptive pathway is associated with lower disease activity in NNP patients and with higher clinical pain in NP patients. Spearman correlation between the alpha power and disease activity (i.e., BASDAI) is shown for the left secondary somatosensory cortex (S2) of the ascending nociceptive pathway. Spearman correlation between the alpha power and trait clinical pain intensity (average pain over the last 4 weeks) is shown for the right primary somatosensory cortex (S1) of the ascending nociceptive pathway. Associations are shown in the entire ankylosing spondylitis (AS) chronic pain group (left), in the mixed inflammatory and neuropathic pain (NP) subgroup (pink, middle), and in the matched inflammatory none-neuropathic pain (NNP, right). Significant correlation is indicated by *. The lines are only meant to visually show treadlines to demonstrate the direction of the Spearman relationship and do not indicate a linear relationship. Brain images are displayed using the radiological convention. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article).