Abnormalities in sensorimotor brain function are related to chronicity of low back pain

Maladaptive plasticity in the brain may contribute to chronic low back pain (LBP) and underlie the altered postural control of the lumbopelvic musculature that is evident in some individuals with LBP. We recently described an MRI-compatible leg-raise paradigm to measure brain activity associated with lumbopelvic postural control. The objective of this study was to compare brain function in young adults with and without a history of LBP and to determine relationships between brain function, pain, and postural control characteristics. We recruited 55 participants with a history of LBP, who were asymptomatic when studied, and 30 healthy controls. Postural control during leg-raise tasks were quantified using electromyography and ground reaction forces. Group differences in movement-related brain activation during the leg-raise tasks were assessed with fMRI and associations among brain activation, postural control, and pain characteristics were examined. Compared with controls, participants with LBP had greater activation in the angular gyri, posterior cingulate cortices; and greater peak signal change in the right angular gyrus, right pre-central gyrus, and left globus pallidus. Abnormal postural control was associated with greater activation in right pre-central gyrus and left posterior cingulate cortex. Worse pain characteristics associated with less activation in left posterior cingulate cortex and more activation in right angular gyrus. Pathological changes in movement-related brain function are evident early in the time-course of LBP, persist between symptomatic episodes, and associate with clinical characteristics. These findings suggest biomarkers of dysfunction in pain-related circuits associated with LBP and have implications for pathophysiology of this condition.