Brain sensory network activity underlies reduced nociceptive initiated and nociplastic pain via acupuncture in fibromyalgia
Sridhar et al. · Communications Medicine · 2026
Evidence Level
STRONGOBJECTIVE
To investigate how electroacupuncture influences nociceptive and nociplastic pain through changes in brain activation and functional connectivity
WHO
Adult women with fibromyalgia (n=44)
DURATION
4 weeks of treatment with pre- and post-treatment assessments
POINTS
LI-11 to LI-4, GB-34 to SP-6, and bilateral ST-36
🔬 Study Design
Electroacupuncture
n=19
8 sessions of electroacupuncture at specific points
Sham Laser
n=25
8 sessions of inactive laser (sham control)
📊 Results in numbers
Correlation widespread pain vs. pressure tolerance (EA)
Correlation widespread pain vs. pressure tolerance (control)
Significant between-group difference
Primary somatosensory cortex activation
📊 Outcome Comparison
S1-anterior insula functional connectivity
This study shows that electroacupuncture can help people with fibromyalgia through a specific mechanism in the brain. The treatment increases pain tolerance and reduces widespread pain by activating brain regions responsible for sensory processing, providing a scientific basis for its therapeutic use.
Article summary
Plain-language narrative summary
This randomized controlled trial investigated the brain mechanisms by which electroacupuncture modulates different types of pain in women with fibromyalgia. Fibromyalgia is a complex condition characterized by widespread pain that involves both nociceptive (peripherally initiated) and nociplastic (centrally maintained) components. Understanding how specific treatments affect these different pain mechanisms is crucial for developing more effective and personalized therapies. The study included 44 women with fibromyalgia who were randomized to receive electroacupuncture (n=19) or sham laser control treatment (n=25) for four weeks.
The electroacupuncture protocol involved eight sessions applied at specific points: LI-11 to LI-4, GB-34 to SP-6, and bilaterally at ST-36. These points were selected based on their clinical relevance for common fibromyalgia symptoms. Participants underwent behavioral assessments and functional neuroimaging before and after treatment, including pressure pain tolerance tests and functional MRI during painful stimulation. The results revealed important differences between the groups.
In the electroacupuncture group, the increase in pressure pain tolerance (a marker of nociceptive pain) correlated significantly with the reduction in widespread pain (a marker of nociplastic pain), with a correlation of -0.48 (p=0.036). This relationship was not observed in the control group (rho=0.14, p=0.501). Neuroimaging analyses showed that electroacupuncture activates specific brain circuits, including greater activation of the primary somatosensory cortex (S1) and stronger functional connectivity between S1 and the anterior insula during painful stimulation. Mediation analyses confirmed that these brain changes explain the relationship between improved pain tolerance and reduced widespread pain.
In contrast, the control group demonstrated a different mechanism, involving reduced activity in the precuneus and lower precuneus-insula connectivity, suggesting a top-down process mediated by expectations. The study proposes that electroacupuncture works through a bottom-up mechanism: peripheral somatosensory stimulation from the needles activates the primary somatosensory cortex, which then strengthens its connectivity with the anterior insula, a region crucial for sensory-emotional integration of pain. This sequential process results in reduced widespread pain. The clinical implications are significant, suggesting that electroacupuncture may be particularly beneficial for patients with mixed pain profiles involving both nociceptive and nociplastic components.
The study also highlights the importance of distinguishing between different pain mechanisms to personalize treatments. Limitations include the modest sample size, inclusion of women only, and the inherent difficulty in completely separating nociceptive from nociplastic pain. Additionally, although the mediation analyses suggest directional relationships, they do not establish definitive causality. Future studies may explore more specific techniques to differentiate pain mechanisms and investigate how baseline patient characteristics may predict treatment response.
Strengths
- 1Randomized controlled design with neuroimaging
- 2Sophisticated mediation analyses
- 3Clear theoretical framework distinguishing nociceptive and nociplastic pain
- 4Multiple complementary outcome measures
Limitations
- 1Small sample size (n=44)
- 2Female participants only
- 3Overlap between markers of nociceptive and nociplastic pain
- 4Temporal separation between behavioral assessments and neuroimaging
Expert Commentary
Dr. Marcus Yu Bin Pai
MD, PhD · Pain Medicine · Physical Medicine and Rehabilitation · Medical Acupuncture
▸ Clinical Relevance
Fibromyalgia represents one of the greatest diagnostic and therapeutic challenges in chronic pain services, precisely because it combines nociceptive and nociplastic components that rarely respond uniformly to pharmacologic approaches alone. What this work brings substantively to practice is the demonstration that electroacupuncture operates through a bottom-up mechanism distinct from placebo effect: peripheral somatic stimulation activates the primary somatosensory cortex and strengthens its connectivity with the anterior insula, resulting in measurable increases in pressure tolerance and reduction in widespread pain. The negative correlation of -0.48 between these two markers in the active group, with p=0.036, contrasts clearly with the absence of correlation in the control group. This has direct implications for therapeutic selection: fibromyalgia patients who present with reduced pressure pain threshold — indicative of associated peripheral sensitization — fit the profile that benefits most from electroacupuncture as a component of the multimodal rehabilitation program.
▸ Notable Findings
The most robust and conceptually rich finding of the study is the dissociation between the mechanisms of action of electroacupuncture and sham control. While the active group recruited greater activation of the primary somatosensory cortex with amplified S1-anterior insula connectivity during painful stimulation, the inactive laser control group presented reduced activity in the precuneus and lower precuneus-insula connectivity — a pattern consistent with top-down modulation mediated by expectation and attention. The mediation analysis confirming that the neuroimaging changes explain the relationship between pressure tolerance and widespread pain is particularly relevant: it inserts electroacupuncture into a coherent neurophysiologic framework, moving the field away from purely subjective explanations. The activation of S1 with p<0.001 during post-treatment painful stimulation suggests functional reorganization of somatosensory processing — data consistent with models of neuroplasticity induced by repeated stimulation.
▸ From My Experience
In my practice at the musculoskeletal pain clinic, I have seen that fibromyalgia patients require careful stratification before any therapeutic decision. Those with predominantly pure central sensitization — without correlate of reduced pressure pain threshold at tender points — tend to respond less predictably to electroacupuncture alone. On the other hand, when there is a peripheral-nociceptive component coexisting with nociplastic pain, I usually observe favorable response by the third to fifth session, with perceptible improvement in sleep quality and exercise tolerance. The usual protocol I use includes 8 to 12 sessions in the acute phase, followed by monthly maintenance, always combined with gradual aerobic exercise and, when necessary, duloxetine or pregabalin. The combination with aquatic physical therapy has shown consistent clinical synergy over the years. The patient profile that responds best, in my experience, is the one with fibromyalgia onset less than five years ago, documentedly low pressure pain threshold, and absence of untreated major depressive disorder.
Full original article
Read the full scientific study
Communications Medicine · 2026
DOI: 10.1038/s43856-025-01280-0
Access original articleScientific Review
Marcus Yu Bin Pai, MD, PhD
CRM-SP: 158074 | RQE: 65523 · 65524 · 655241
PhD in Health Sciences, University of São Paulo. Board-certified in Pain Medicine, Physical Medicine and Rehabilitation, and Medical Acupuncture. Scientific review and curation of every entry in this library.
Learn more about the author →Medical disclaimer: This content is for educational purposes only and does not replace consultation, diagnosis, or treatment by a qualified professional. Some information may be assisted by artificial intelligence and is subject to inaccuracies. Always consult a physician.
Content reviewed by the medical team at CEIMEC — Integrated Centre for Chinese Medicine Studies, a reference in Medical Acupuncture for over 30 years.
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