Chronic Back Pain Flare-Ups Activate the Brain’s Sense-of-Self Network

Movement-triggered back pain appears to engage brain systems tied to self-reflection, not just the circuits that register a physical threat. That distinction, seen in brain scans of 114 people with chronic low back pain, may help explain why a flare can affect someone’s thoughts and expectations long after the movement that set it off.

The study, led by researchers at UC San Diego School of Medicine and published October 5, 2026, in the British Journal of Anaesthesia, focused on the brain’s Default Mode Network (DMN). Often called the “self network,” the DMN includes connected regions in the frontal, parietal, and temporal lobes. It tends to be active during inward-focused thought, including reflection on personal memories, identity, and emotions.

In the researchers’ experiment, the DMN became more active during a movement-triggered chronic back pain flare. When participants felt a separate, brief heat pain, the network became less active, following the pattern typically associated with acute pain. The contrast suggests that the brain processes these two pain experiences differently.

A movement test revealed a different brain response

To provoke back pain, participants completed a leg raise test, a standard clinical procedure. While they did so, the researchers used arterial spin labeling, a functional MRI method that tracks brain blood flow without an injected contrast agent.

The team also exposed participants to a harmless but uncomfortable heat sensation on the calf. The researchers compared brain activity during that stimulus with activity during the movement test, which could trigger a flare of the participants’ chronic pain.

The difference centered on the DMN. During the heat stimulus, the network quieted, as it generally does when attention shifts toward an immediate external sensation. During a movement-triggered flare, it became more active. The finding points to a distinction between the brain’s response to a short-lived painful stimulus and its response to a flare of an ongoing condition.

Low back pain is the leading cause of disability worldwide, according to the World Health Organization. Pain is considered chronic when it persists for more than 12 weeks. For people living with the condition, ordinary actions can provoke sudden episodes, making movement itself a source of concern.

The brain’s role in pain has long been clear, but the circuits involved in pain triggered by movement have been harder to pin down. The UC San Diego study offers evidence that such flares recruit a network associated with internal thought, where physical sensation may become bound up with personal experience.

Why a flare can reach beyond the painful moment

Corresponding author Fadel Zeidan, a professor in UC San Diego’s Department of Anesthesiology and director of its Pain Health and Mindfulness Laboratory, described the result as a reversal of the usual DMN response to pain.

“In every pain study, when you're experiencing pain, the DMN deactivates,” Zeidan said. “What we show for the first time ever is that when you have a pain flare, it turns on instead. You start to identify the experience with who you are.”

That interpretation suggests a flare may involve more than the brain registering a painful sensation. Memories of previous episodes, worries about when pain might return, and expectations about movement could also shape the experience. A person’s day may be affected by anticipating a flare or recovering from one, even when the sharpest pain has passed.

Zeidan described that broader burden this way: “The moment-to-moment experience is contaminated not only by the feeling of pain, but by the anticipation of it and recovery from it. It's contaminated by past experiences like embarrassment about not being able to participate in normal activities and fear of movement when trying to avoid the pain.”

The study does not establish that the DMN causes chronic pain or that its activity explains every patient’s experience. It does, however, identify a brain response that differs between movement-triggered flares and the heat stimulus used for comparison. That may help researchers investigate why pain can become intertwined with a person’s expectations, emotions, and sense of self.

Rethinking what treatment needs to address

Many pain treatments are designed to reduce the sensation or dampen pain signaling. Zeidan argued that this focus may leave some of the personal and emotional dimensions of persistent pain untouched. “Current pain medicine is fixated on ridding patients of their pain symptoms, but that's not the source of chronic pain,” he said. “These data suggest that a chronic pain flare also encompasses one's identity.”

The findings could therefore influence how scientists frame future treatment research. If a flare engages networks involved in inward-focused thought, therapies might aim to change how people relate to pain as well as how strongly they feel it. That would not necessarily mean eliminating the pain; it could mean reducing how much it shapes daily decisions and emotional life.

Zeidan and colleagues are examining mindfulness meditation and psilocybin as possible approaches. Previous work from the group has explored mindfulness meditation and the psychedelic compound psilocybin. Both are being studied for their potential to affect how pain relates to identity, past experience, and anticipation.

Mindfulness practice encourages people to notice sensations, thoughts, and emotions without immediately judging or reacting to them. Psilocybin is being investigated for its possible effects on brain processes that integrate pain with earlier experiences and future worries. The researchers’ proposal is that these approaches may alter the relationship a person has with pain, rather than simply erasing the sensation.

Zeidan cautioned against treating either approach as a guaranteed fix. “They're not a silver bullet -- you're not necessarily getting rid of the pain, but you're changing the relationship you have with that pain so it doesn't contaminate your everyday life.”

His laboratory is conducting clinical trials that use brain imaging to study whether mindfulness and psychedelic treatments can change neural processes involved in self-reflection. The current study provides a reason to examine those processes, but it does not show that either intervention changes DMN activity or improves outcomes for people with chronic back pain. More research will be needed to establish whether these approaches help and for whom.

What the study adds

The practical contribution is a clearer target for research: movement-triggered chronic pain may have a brain signature that differs from an acute painful stimulus. For clinicians and researchers, that distinction offers a way to ask whether treatment should account for anticipation, memory, and a patient’s interpretation of pain alongside its physical intensity.

Study coauthors from UC San Diego School of Medicine include Morgan Gianola, Jon Dean, Conan Chen, Daniel Barrows, Gabriel Reigner, and Thomas Liu. Funding came in part from the National Institutes of Health’s National Center for Complementary and Integrative Health (Grant #R01AT009693) and the UC San Diego Sanford Institute for Empathy and Compassion. The researchers reported no conflicts of interest.

For now, the study’s strongest message is that a chronic pain flare may recruit brain activity associated with the inner life of the person experiencing it. Mapping that connection could help researchers build treatments around the full experience of persistent pain, while further trials determine whether changing that connection makes everyday life easier.