European journal of pain : EJP
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Chronic pain involves communication between neural and immune systems. Recent data suggest localization of glial (brain immune cells) activation to the sensorimotor regions of the brain cortex (S1/M1) in chronic low back pain (LBP). As glia perform diverse functions that impact neural function, activation might contribute to sensorimotor changes, particularly in LBP maintained by increased nervous system sensitivity (i.e., nociplastic pain). This preliminary proof-of-concept study aimed to: (i) compare evidence of neuroinflammatory activation in S1/M1 between individuals with and without LBP (and between nociceptive and nociplastic LBP phenotypes), and (ii) evaluate relationships between neuroinflammatory activation and sensorimotor function. ⋯ Neuroinflammatory activation localized to sensorimotor areas of the brain in individuals with nociplastic pain might contribute to changes in sensory and motor function and aspects of central sensitization. If cause-effect relationships are established in longitudinal studies, this may direct development of therapies that target neuroinflammatory activation.
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Vagal activity has analgesic effects that are attributed to exercise-induced hypoalgesia (EIH). High vagal tone and low pain sensitivity are reported in individuals who routinely exercise yet, their association is unclear. Furthermore, it is unknown if the heightened vagal tone following high physical activity predicts and intensifies EIH. ⋯ Highly physically active individuals exhibit greater vagal tone and reduced sensitivity to experimental pain, yet they do not benefit more from exercise-induced hypoalgesia (EIH) compared to low-moderately active individuals. Moreover, low-moderately active individuals with greater vagal tone exhibited more efficient endogenous pain inhibition and greater EIH, suggestive of the moderation effect of physical activity level on vagal-pain associations.
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Low back pain (LBP) is increasingly understood as a long-lasting condition with a variable course. Avoidance and persistence behaviour have been described to mediate pain persistence by potentially linking psychosocial factors and biomechanics. The resulting maladaptive changes in musculoskeletal structures can result in movement control impairment (MCI). This investigation aimed to observe avoidance and persistence behaviour and MCI in participants with acute LBP over 1 year and explore their association with pain persistence. ⋯ In acute low back pain (LBP), maintaining usual activities despite pain and distress can contribute to the continuation of LBP. Alongside a multidimensional approach that considers physical and psychological factors, attitudes toward daily activities are also important. Screening for both maladaptive and adaptive activity patterns in individuals with acute LBP is essential for effective LBP management, improving patient outcomes, and preventing persistent pain.