In 114 patients, movement-triggered back pain activated the default mode network, which normally quiets during acute pain. Researchers say the finding may help explain why pain drugs often fall short.
Researchers at the UC San Diego School of Medicine report that flares of chronic low back pain triggered by movement activate the brain's Default Mode Network, a set of frontal, parietal and temporal regions linked to self-reflection, memory and a person's sense of identity. In most pain studies this network becomes less active, because the brain shifts its attention toward an immediate external threat. The work, published on 5 October 2026 in the British Journal of Anaesthesia, suggests that persistent back pain may be woven into how patients experience themselves, not only into how the body signals damage.
The team recruited 114 people with chronic low back pain, defined as pain lasting more than 12 weeks. Each completed a standard leg raise test to provoke a flare while brain blood flow was measured with arterial spin labelling, a type of functional MRI that needs no injected contrast agent. The researchers also applied a harmless but uncomfortable heat stimulus to the calf. Heat reduced activity in the Default Mode Network, as expected for acute pain, while the movement-triggered back pain increased it. Corresponding author Fadel Zeidan said that during a flare 'you start to identify the experience with who you are.'
The authors argue the result could help explain why treatments that mainly dampen pain signalling, such as opioids, often give limited relief in chronic back pain, which the World Health Organization names as the leading cause of disability worldwide. Zeidan's group has previously studied mindfulness meditation and the psychedelic compound psilocybin as ways of changing a person's relationship with pain. The researchers stress these approaches are not a cure and need further research. This account is based on a university-supported report of a single study, and the findings describe brain activity during pain flares rather than proof of a new treatment.
