A provoked flare-up of chronic back pain raised default mode network activity in 114 adults
A study with UC San Diego co-authors scanned 114 adults with chronic back pain after a provoked flare and saw default mode network activity rise. An outside neuroscientist praised the design but said lingering pain or anxiety could also explain the signal.
The Scientist · Science desk
Key figures: the leg-movement test increased participants' reported pain intensity by 23% on average; each leg was held in position for 10 seconds; the study recruited 114 adults with chronic lower back pain.
| Figure | Value | Note | Claim |
|---|---|---|---|
| Average rise in reported pain intensity after leg test | 23% | 4 | |
| Leg held in painful position | 10 seconds | 3 | |
| Chronic lower back pain | 114 adults | 1 |
What happened
- Studies show acute pain, such as a burn or a knock to the knee, lowers default mode network activity, so a rise during a flare-up was unexpected.
- A researcher lifted each participant's leg until the back hurt more, held it for 10 seconds and lowered it; scans taken immediately afterward were compared with earlier ones.
- The leg raise increased participants' reported pain intensity by 23% on average.
Why it matters
- contradiction Heat and a provoked back flare moved the same network in opposite directions in the same participants, so any account of chronic pain has to explain both.
- constraint The trigger was a 10-second laboratory hold, so the result speaks to a brief provoked flare; flares from bending to tie a shoe remain untested.
- decision Anyone building on this must choose how to separate self-reference from mind wandering and from post-movement anxiety before the self-related label can be used.
Scanners and flare-ups do not mix well. Researchers typically avoid movement during brain scans because it can interfere with scan clarity, according to Katherine Martucci, a Duke neuroscientist who was not involved in the study [17]. This design "nicely gets around" the problem, she told Live Science in an email, by scanning before and after the painful motion [17].
The workaround has a cost. Each scan came immediately after the leg was lowered and was compared with the participant's own earlier scan [3]. fMRI tracks blood flow, an indirect measure of brain activity [2]. Martucci noted that what the scanner saw could also reflect lingering pain or anxiety following the painful leg raise [18].
The heat condition is the useful comparison. The same participants had painful heat applied to their calves, and part of their default mode network quieted [8]. Acute-pain studies predict exactly that [6]. We think this makes it unlikely that the rise after the leg raise is a generic response to pain in these people. But heat on the calf and a leg raise that aggravates the back differ in several ways at once, including body site and whether the pain is one the person already lives with. The thing this doesn't tell you is which of those differences produced the opposite result.
The paper, published Oct. 5 in the British Journal of Anaesthesia [7], surprised its own authors. Fadel Zeidan, a co-author and neuroscientist at UC San Diego, said the team had not expected the default mode network to be involved at all [10]. Co-author Morgan Gianola, a postdoctoral scholar at the same university, told Live Science: "When we saw just the first round of analysis, we're like, 'Did we do it right?'" [12]
The authors' reading is that chronic pain may become intertwined with how people perceive themselves and their bodies [13]. The support is a correlation: participants with more severe chronic back pain had stronger connectivity between the default mode network and regions that process sensations from the back [9]. "This pain flare has almost become a part of who they are from an egocentric perspective," Zeidan said [11].
A correlation across people gives no direction. Severe pain might pull the network in, or a more self-focused state might amplify the pain. The network also lights up during mind wandering as well as self-reflection [16], so a rise fits either function. In our view, the direction of the effect is the finding to take from the paper, and the self-related interpretation is a hypothesis that this design cannot test.
What to watch
- A follow-up that scans during the movement or at several delays afterward, which would separate lingering pain or anxiety from the flare response.
- Whether the link between pain severity and default mode connectivity holds in a separate group of patients or within one person over time.
- Whether other pain triggers or other pain sites produce the same default mode rise that the leg raise did.
Clarity's read
What the record supports and how the coverage leans. The claims behind it follow.
Reality
- Evidence55
- Adoption
- Insufficient
- Hype gap+15
- Incentives
- Insufficient
- Confidence50
Claim ledger
Ranked by verification strength, evidence, and original report placement.
- [1]
Researchers recruited 114 adults with chronic lower back pain and used functional magnetic resonance imaging (fMRI) to examine their brain activity.
- [2]
fMRI measures changes in blood flow, which acts as an indirect measure of brain activity.
- [3]
After an initial scan, a researcher helped lift each participant's leg until their back pain increased, held it in position for 10 seconds, and then lowered it; researchers scanned participants' brains immediately after the movement and compared the results with scans collected beforehand.
- [4]
On average, the leg-movement test increased the participants' reported pain intensity by 23%.
- [5]
Movement-induced chronic back pain was tied to increased activity in the brain's default mode network.
- [6]
Acute pain lowers activity in the default mode network, studies show, presumably because it induces an awareness of something separate from yourself; the network typically becomes less active during acute pain such as touching a hot stove or banging a knee.
- [7]
The study was published Oct. 5 in the British Journal of Anaesthesia.
- [8]
Researchers also exposed participants' calves to painful heat; unlike the movement-induced back pain, the heat was associated with reduced activity in part of the default mode network.
- [9]
Participants who reported more severe chronic back pain had stronger connectivity between the default mode network and brain regions that process sensations from the back.
- [10]
"We did not expect [the default mode network] to be involved at all," said study co-author Fadel Zeidan, a neuroscientist at UC San Diego.
- [11]
"This pain flare has almost become a part of who they are from an egocentric perspective," Zeidan said.
- [12]
"When we saw just the first round of analysis, we're like, 'Did we do it right?'" said study co-author Morgan Gianola, a postdoctoral scholar at the University of California, San Diego.
- [13]
The study authors concluded that chronic pain may become intertwined with how people perceive themselves and their bodies.
- [14]
Everyday movements like bending down to tie shoes or picking up a grocery bag can trigger painful flare-ups in people with chronic back pain.
- [15]
Study co-authors Morgan Gianola and Fadel Zeidan are at the University of California, San Diego.
- [16]
The default mode network is a group of connected brain regions that lights up during self-reflection and mind wandering.
- [17]
Katherine Martucci, a neuroscientist at Duke University who was not involved in the study, said researchers typically avoid movement during brain scans because it can interfere with the clarity of the scan, and that the study 'nicely gets around' that problem by taking scans before and after the painful motion.
- [18]
Martucci noted that the observed brain activity could also reflect lingering pain or anxiety following the painful leg raise.
Get this ledger inside ChatGPT. Ask about any of our stories and the answer brings its figure, each claim’s verdict and the sources. Free, no account.
Sources
1 independent publisher whose own reporting we read for this story.
- livescience.comChronic back pain may activate an unexpected brain network, study finds
1 article · October 14, 2026
Topics and entities
Follow any of these and your For You feed starts watching them — no settings page required.
Topics
- Default mode networkFollow
- NeuroimagingFollow
- Chronic painFollow
Entities
- Live ScienceFollow
- British Journal of AnaesthesiaFollow
- Fadel ZeidanFollow
- Katherine MartucciFollow
- University of California San DiegoFollow