In a scanner at UC San Diego, people living with chronic low back pain were asked to lift a leg, a simple movement that reliably brought their pain back. What the brain did in those moments ran against expectation: the network associated with inner reflection and personal identity grew more active rather than quieting, as it does when pain is sudden and brief. It suggests that persistent pain may be less a message from the body alone than a story the self begins to tell about itself, and that this is part of why familiar remedies so often fall short.
Chronic Back Pain Flares May Switch On the Brain's 'Self Network,' UC San Diego Study Finds
Chronic low back pain, the leading cause of disability worldwide, can be provoked by everyday movement and often resists conventional treatment, affecting patients' daily lives and identity.
When you have a pain flare, it turns on instead.
Mark
Why is it such a big deal that this network turns on rather than off?
Mimi
Because in every earlier pain study it shut down. Here, during a back pain flare, it switched on, and Zeidan says that's the first time it's been shown.
Mark
And the same people showed both responses?
Mimi
Yes. The heat on the calf quieted the network in these same participants, while the leg raise flare activated it.
Luke
Let me slow down. The scans show the network becoming active. Calling that 'identity' is the researchers' interpretation, not something the imaging measured directly.
Mimi
That's fair. The link to memory and self comes from what the network is known to do, plus the pattern with severity in the somatosensory connections.
Mark
What about the treatment angle?
Mimi
Opiates target pain signaling. Zeidan argues that misses the identity piece. Mindfulness and psilocybin are being studied to loosen that tie.
Luke
But the source says early findings need confirmation, and the new study didn't test either treatment. So the claim that medications fall short for this reason is a hypothesis.
Mark
Anything solid to hold onto?
Mimi
Heart rate tracked flare intensity reliably, and the trials now underway use imaging to test whether the self-network actually changes.
Luke
Which is the right test. We'll know more when those results arrive.
O Pulso
- A simple leg raise, a standard clinical test, becomes the trigger that reveals a surprising shift in how the brain handles pain.
- While acute heat pain quiets the brain's self network, movement-triggered back pain switches it on, pulling identity into the experience.
- Stronger links between the self network and sensory regions track with greater pain severity, tying chronic pain to memory and selfhood.
- Medications aimed mainly at pain signals may miss these deeper circuits, leaving patients with limited relief from a condition that is the world's leading cause of disability.
- Researchers are now testing mindfulness and psilocybin in clinical trials to see whether changing the pain-self connection can ease pain's grip on daily life, though results remain early.
In a scanner at UC San Diego, people living with chronic low back pain were asked to lift a leg, a simple movement that reliably brought their pain back. What the brain did in those moments ran against expectation: the network associated with inner reflection and personal identity grew more active rather than quieting, as it does when pain is sudden and brief. It suggests that persistent pain may be less a message from the body alone than a story the self begins to tell about itself, and that this is part of why familiar remedies so often fall short.
In a brain scanner at UC San Diego, 114 people with chronic low back pain were asked to lift a leg, a movement that clinicians use to provoke their pain. For these patients, it did exactly that. The researchers were watching the brain's Default Mode Network, the set of regions that becomes active when attention turns inward toward memory, identity and one's own thoughts.
In ordinary acute pain, this network goes quiet, as the mind turns outward toward the threat. The team confirmed this by applying a brief, harmless heat to the calf. But during the back pain flare, the network became more active instead. Patients with more severe pain also showed stronger links between this self network and the region that processes physical sensation.
Fadel Zeidan, the study's lead author, described the shift simply: when a flare arrives, people begin to identify the experience with who they are. Each flare is colored by fear of movement, by embarrassment at missing ordinary life, and by worry about what comes next. This may help explain why medications aimed mainly at pain signals so often disappoint.
His group is now testing mindfulness and psilocybin, not as cures, but as ways to change a person's relationship with pain. The early results are encouraging, though they still need confirmation.
In a scanner at UC San Diego, 114 people with chronic low back pain were each asked to do something simple: lift a leg. The movement is a standard clinical test for provoking back pain, and for these patients it did what it was meant to do. What the researchers saw in the brain while the pain flared was not what pain research would have predicted.
The study, published October 5, 2026, in the British Journal of Anaesthesia, centers on the Default Mode Network, often called the brain's "self network." It is a set of connected regions across the frontal, parietal and temporal lobes that becomes busy when attention turns inward: reflecting on personal experience, thinking about identity, considering one's own thoughts and emotions. It generally quiets when attention is directed at something happening in the outside world.
In ordinary acute pain, the network quiets too. The brain appears to pull attention away from inner thought and toward the immediate threat. The team confirmed this in the same participants by applying a harmless but uncomfortable heat stimulus to the calf, the kind of brief sting you might feel touching a hot stove. During the heat, the Default Mode Network became less active, as expected.
During the movement-triggered back pain flare, it did the opposite. Activity in the network rose. To track this, the researchers used arterial spin labeling, a functional MRI method that follows brain activity through blood flow and needs no injected contrast agent.
Other patterns emerged. Patients with more severe chronic back pain showed stronger connections between the Default Mode Network and the primary somatosensory cortex, the region that processes physical sensation, including signals from the back. Higher pain intensity during the leg raise was linked to more activity in regions involved in sensation and movement. And heart rate increases during the test reliably tracked how intense the flare was.
"In every pain study, when you're experiencing pain, the DMN deactivates," said corresponding author Fadel Zeidan, a professor of anesthesiology and director of the Pain Health and Mindfulness Laboratory at 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." He described the moment-to-moment experience as contaminated by anticipation of pain and recovery from it, and by past experiences such as embarrassment over being unable to join normal activities and fear of movement.
The scale of the problem is large. The World Health Organization names low back pain the leading cause of disability worldwide, and pain lasting beyond 12 weeks is considered chronic. For many patients, everyday movement can set off sudden flares. Researchers have long struggled to pin down the specific brain circuits behind movement-triggered pain.
The findings may bear on why treatment so often disappoints. Medications such as opiates mainly target pain signaling, and may not reach networks involved in the emotional and personal dimensions of persistent pain. "Current pain medicine is fixated on ridding patients of their pain symptoms," Zeidan said, but that is not the source of chronic pain; the data suggest a flare also encompasses identity.
Zeidan's group has examined two alternatives: mindfulness meditation and the psychedelic compound psilocybin. Mindfulness cultivates non-judgmental awareness of the present moment. Psilocybin, Zeidan said, seemingly resets the pain system that integrates trauma, past experiences and future worries. Neither is a silver bullet, he cautioned; the aim is to change a person's relationship with pain so it does not contaminate daily life. Early findings suggest this may reduce pain intensity, though more research is needed.
The lab is now running several clinical trials that use brain imaging to test whether these treatments change the neural processes of self-reflection. Co-authors include Morgan Gianola, Jon Dean, Conan Chen, Daniel Barrows, Gabriel Reigner and Thomas Liu. Funding came in part from the National Center for Complementary and Integrative Health (Grant R01AT009693) and the Sanford Institute for Empathy and Compassion, with no conflicts of interest reported.
Citações Notáveis
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.— Fadel Zeidan, UC San Diego School of Medicine
They're not a silver bullet; you're changing the relationship you have with that pain so it doesn't contaminate your everyday life.— Fadel Zeidan, on mindfulness and psilocybin
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