Chronic low back pain was associated with increased connectivity between the primary somatosensory cortex and both the salience and default mode networks compared with healthy adults.
Observational (n=181)
Do physical maneuvers that exacerbate pain alter brain connectivity between S1, salience network, and DMN in patients with chronic low back pain?
In patients with chronic low back pain, pain exacerbation shifts somatotopically specific brain connectivity from the default mode network to the salience network, a process moderated by pain catastrophizing.
Although several studies have found that chronic pain is characterized by increased cross-network connectivity between salience network, sensorimotor network, and default mode network (DMN), a large sample-size investigation allowing for a more reliable evaluation of somatotopic specificity and subgroup analyses with linkage to clinical pain intensity has been lacking. We enrolled healthy adults and a large cohort of patients (N = 181) suffering from chronic low back pain (cLBP). To specifically link brain connectivity with clinical pain intensity, patients were scanned at baseline and after performing physical maneuvers that exacerbated pain. Compared with healthy adults, patients with cLBP demonstrated increased connectivity between the functionally localized back representation in the primary somatosensory cortex (S1back) and both salience network and DMN. Pain exacerbation maneuvers increased S1back connectivity to salience network regions, but decreased connectivity to DMN, with greater pain intensity increase associated with greater shifts in these connectivity patterns. Furthermore, only in patients with cLBP reporting high pain catastrophizing, DMN connectivity was increased to a cardinal node of the salience network, anterior insula cortex, which was correlated with increased postmaneuver pain in this cLBP subgroup. Hence, increased information transfer between salience processing regions, particularly anterior insula, and DMN may be strongly influenced by pain catastrophizing. Increased information transfer between the salience network and S1 likely plays an important role in shifting nociceptive afference away from self-referential processing, reallocating attentional focus, and affective coding of nociceptive afference from specific body areas. These results demonstrate S1 somatotopic specificity for cross-network connectivity in encoding clinical back pain and moderating influence of catastrophizing for DMN/insula connectivity.
Kim et al. (2019) conducted an observational in Chronic low back pain (n=181). Chronic low back pain and pain exacerbation maneuvers vs. Healthy adults and baseline state was evaluated on Brain connectivity between the primary somatosensory cortex (S1back), salience network, and default mode network (DMN). Chronic low back pain was associated with increased connectivity between the primary somatosensory cortex and both the salience and default mode networks compared with healthy adults.