For people living with chronic back pain, even a simple, ordinary movement can trigger a sudden, debilitating surge of agony. Now, in a discovery that upends long-held assumptions about how the brain handles persistent distress, scientists have found that these painful episodes activate a surprising part of the brain—one that is closely connected to human identity, personal history, and how individuals think about themselves.
Researchers at the UC San Diego School of Medicine have discovered that movement-triggered pain in people suffering from chronic low back pain activates a specific brain network that normally becomes less active during ordinary, acute pain. This groundbreaking finding suggests that persistent back pain becomes deeply intertwined with a person’s sense of self, which could fundamentally explain why conventional pain treatments so frequently provide limited or temporary relief.
According to data from the World Health Organization, low back pain stands as the leading cause of disability worldwide. When physical pain persists for more than 12 weeks, medical professionals classify it as chronic. For millions of patients globally, everyday movements—such as bending down to tie a shoe, reaching for an item on a shelf, or simply getting out of a chair—can provoke sudden, severe flare-ups that make an already challenging condition exceptionally difficult to manage in professional and personal life.
Although medical science has long understood that the brain plays a central and commanding role in how pain is perceived and experienced, researchers have historically struggled to identify the precise neural circuits responsible for the sudden pain triggered specifically by movement in chronic sufferers.
Chronic Back Pain Activates the Brain’s Sense of Self
The new study, published in the British Journal of Anaesthesia, identified an unexpected and telling neural response involving the brain’s Default Mode Network, commonly referred to as the DMN.
Sometimes called the "self network," the DMN consists of a complex, interconnected web of regions spanning the frontal, parietal, and temporal lobes of the brain. These specific areas are exceptionally active when a person’s attention turns inward, such as during moments of self-reflection, when considering personal identity, or when processing one’s inner thoughts and emotions. In stark contrast, this same network generally dampens down and becomes less active when individuals direct their attention outward toward something happening in their external environment.
The researchers at UC San Diego discovered that sudden back pain caused by routine movement surprisingly switched this network on rather than off. This unusual physiological response strongly suggests that chronic pain encompasses far more than the mere mechanical processing of physical sensory signals. Instead, it actively engages the brain systems responsible for shaping how people experience themselves as individuals.
These findings could significantly help researchers and clinicians understand why therapeutic interventions that focus primarily on suppressing basic pain symptoms do not always work effectively for patients with chronic low back pain. Furthermore, the discovery raises the compelling possibility that directly targeting the Default Mode Network could offer an entirely different, more holistic approach to treatment in the future.
Brain Scans Reveal a Surprising Difference Between Chronic and Acute Pain
To investigate what precisely happens inside the brain during a spontaneous pain flare, the research team recruited 114 patients diagnosed with chronic low back pain.
Each study participant completed a standard clinical assessment known as a "leg raise test," which is routinely used in medical settings to safely provoke back pain. During this procedure, researchers carefully monitored changes in the patients’ brain blood flow using a specialized, advanced functional MRI method called arterial spin labeling. This sophisticated technique allows scientists to accurately track dynamic patterns of brain activity by measuring blood flow in real time without the need to rely on an injected contrast agent.
To provide a point of comparison, the research team also examined how the participants responded to a separate, controlled painful stimulus. They applied a harmless but genuinely uncomfortable heat sensation to the participant’s calf, mimicking the brief, sharp pain someone might experience if they accidentally brushed against a hot stove.
When the scientists compared these two distinct situations, a striking and definitive difference emerged.
When movement triggered a flare of chronic back pain, the brain’s Default Mode Network significantly increased its activity. However, when those exact same participants experienced the acute painful heat stimulus, that very same network decreased its activity, behaving in strict accordance with the brain’s typical, expected response to acute physical pain.
These collective findings provide robust new evidence that chronic pain flares involve complex brain processes associated deeply with personal identity and self-referential thought, rather than being limited to the straightforward physical sensation of tissue damage or nociception.
Why the Brain Reacts Differently to Chronic Pain
During ordinary acute pain, a healthy human brain generally reduces activity within the Default Mode Network so that it can concentrate all available cognitive resources on the immediate source of physical danger. This evolutionary response helps shift attention swiftly away from internal daydreams or thoughts and toward an external threat demanding immediate action.
However, the UC San Diego researchers found that movement-triggered chronic back pain produced the exact opposite neurological effect.
"In every pain study, when you’re experiencing pain, the DMN deactivates," explained corresponding author Fadel Zeidan, PhD, a professor in the Department of Anesthesiology, endowed professor at the Sanford Institute for Empathy and Compassion, and director of the Pain Health and Mindfulness Laboratory at the UC San Diego School of Medicine. "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."
The findings strongly suggest that chronic back pain can become intimately connected with the brain’s internal neural representation of the self. Rather than processing pain solely as a localized physical warning signal originating from the spine or back muscles, the brain may also link the sensation directly to personal memories, long-term expectations, and past emotional experiences.
For someone living with chronic, day-to-day pain, this neurological reality means that the experience extends far beyond the brief moments when the pain is physically present in the body. Persistent worry about when the next flare might strike, vivid memories of previous debilitating episodes, and a learned fear of routine movements that might provoke agony can all become deeply embedded elements of everyday existence.
"The moment-to-moment experience is contaminated not only by the feeling of pain, but by the anticipation of it and recovery from it," Zeidan noted. "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."
This profound connection between physical pain and personal identity helps explain why chronic back pain is notoriously difficult to resolve through standard medical avenues.
A New Direction for Chronic Back Pain Treatment
Because movement-triggered chronic back pain engages distinctly different brain networks compared to ordinary acute pain, researchers believe that traditional treatments often fail to address the underlying neural processes that sustain the condition over months and years.
Conventional pharmacological treatments, such as opioid medications, primarily target basic pain signaling pathways in the nervous system. Yet, they may fail to adequately address the higher-level brain networks involved in the emotional, cognitive, and personal dimensions of persistent suffering.
"Current pain medicine is fixated on ridding patients of their pain symptoms, but that’s not the source of chronic pain," Zeidan said. "These data suggest that a chronic pain flare also encompasses one’s identity."
This vital discovery points directly toward innovative treatment strategies that address not only the raw sensation of physical pain, but also the brain’s complex psychological and neural relationship with that sensation.
Recent investigative work conducted by Zeidan and his academic colleagues has explored two potential mind-body approaches: mindfulness meditation and the administration of the psychedelic compound psilocybin.
Both of these therapeutic avenues are currently being rigorously investigated for their unique ability to help individuals experience physical discomfort without allowing it to become so inextricably bound to their personal identity. Early findings from these lines of research suggest that altering this cognitive and neurological relationship may successfully reduce perceived pain intensity, though additional clinical research remains necessary to confirm these results and establish broad efficacy.
"These types of mind-body and psychedelic medicine approaches target the whole person," Zeidan explained. "Mindfulness is a meditation technique that’s about cultivating non-judgmental awareness of the present moment that dramatically reduces pain in a very unique way. Psilocybin seemingly resets the pain system that integrates trauma, past experiences and future worries to facilitate a restart, if you will. 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."
Rather than attempting to eliminate every physiological pain signal entirely, these advanced therapeutic approaches aim to fundamentally change how the brain interprets, evaluates, and responds to the overall experience. Mindfulness meditation encourages individuals to observe their thoughts, emotional states, and physical sensations without immediately reacting or assigning harsh judgments. Simultaneously, psilocybin is being explored for its potential to temporarily disrupt rigid neural patterns that connect current pain with earlier life trauma, emotional distress, and pessimistic expectations about the future.
The ultimate objective of these novel interventions is not necessarily to remove physical pain from the body altogether, but rather to diminish the heavy toll it takes on a person’s thoughts, emotions, and daily functioning.
The Zeidan laboratory at UC San Diego is currently conducting several ongoing clinical trials utilizing advanced neuroimaging to investigate whether mindfulness-based interventions and psychedelic therapies can successfully modify the specific neural processes involved in self-reflection. Researchers hope these trials will definitively determine whether such approaches can reshape aberrant brain activity and substantially improve how chronic pain patients experience their condition on a subjective level.
Although this line of scientific inquiry remains at a relatively early stage, the findings offer a radically different framework for understanding persistent back pain. By uncovering why the brain links chronic physical pain with an individual’s core sense of self, scientists are laying the essential groundwork for future treatments capable of addressing the complex dimensions of pain that conventional medical therapies so often overlook.
Additional study authors contributing to the research at the UC San Diego School of Medicine include Morgan Gianola, Jon Dean, Conan Chen, Daniel Barrows, Gabriel Reigner, and Thomas Liu.
Financial support for the study was provided in part by the National Institutes of Health’s National Center for Complementary and Integrative Health under grant number R01AT009693, alongside backing from the UC San Diego Sanford Institute for Empathy and Compassion. The study authors reported no conflicts of interest related to the research.
