Fibromyalgia represents one of the greatest therapeutic challenges of contemporary medicine: a condition of chronic generalized pain, without an established biological marker, mediated by alterations in central pain processing — the so-called central sensitization. Available pharmacologic options offer partial relief in only a fraction of patients and carry significant adverse effects. A new randomized clinical trial, published in Communications Medicine (Nature Portfolio), used functional magnetic resonance imaging (fMRI) to investigate how electroacupuncture modifies brain activity and connectivity in women with fibromyalgia — and identified the somatosensory-insular circuit as the neural mediator of generalized nociplastic pain reduction.
CLINICAL TRIAL DATA
Study design and control
In the trial (NCT02064296), women with fibromyalgia were randomized to active electroacupuncture (n = 19) or sham stimulation with inactive laser (n = 25) applied at the same points, over four weeks. The use of inactive laser as a control — instead of sham acupuncture with needles — ensures that any difference observed between groups is not attributable to physical needle insertion per se, but specifically to the electrical stimulus transmitted by the acupoints. All participants underwent fMRI examinations before and after treatment, with assessment of pressure pain (algometry) and standardized scales of generalized pain.
The brain circuit of analgesia by electroacupuncture
The fMRI analysis revealed a consistent and specific pattern in the active electroacupuncture group: reductions in generalized pain were associated with increases in pressure pain tolerance, and this relationship was mediated by two objective neurologic findings. First, greater activation of the primary somatosensory cortex (S1) during painful pressure stimulation. Second, significantly stronger functional connectivity between S1 and the anterior insula — a critical region for the integration of the sensory and affective dimensions of pain.
NEUROIMAGING FINDINGS (ELECTROACUPUNCTURE GROUP)
The “bottom-up” mechanism: from periphery to brain
The authors propose that electroacupuncture acts through a bottom-upmechanism — that is, from below upward: peripheral electrical stimulation at the acupoints activates somatosensory afferents that reach S1, amplify discriminative sensory processing, and strengthen functional connectivity with the insula. This S1-insula circuit, when modulated, creates a sensory “grounding” that counterbalances the central pain amplification characteristic of fibromyalgia — central sensitization. The implication is that electroacupuncture does not suppress pain in a nonspecific central manner, but reorganizes the way the brain processes and integrates peripheral nociceptive signals.
Implications for the treatment of fibromyalgia
Fibromyalgia is one of the most debated indications for medical acupuncture, precisely because of patient heterogeneity and the absence of objective biomarkers of response. This study offers, for the first time, a neuroimaging marker of response to electroacupuncture: the increase in S1-insula connectivity. Although the sample is small (n = 44) and the results require replication in larger and multicenter trials, the identified mechanism is specific, measurable, and biologically plausible — attributes that confer translational solidity to the evidence generated.
Frequently Asked Questions
Electroacupuncture applies electrical microcurrents between pairs of needles inserted at acupoints, allowing precise control of the frequency (Hz) and intensity of the stimulus. In fibromyalgia, low frequencies (2-4 Hz) stimulate the release of beta-endorphins, while high frequencies (80-100 Hz) favor dynorphins — both with central analgesic effect. Electroacupuncture also allows maintaining the stimulus for prolonged periods without technical fatigue, which may be relevant for the modulation of brain networks as demonstrated in this study.
No. Fibromyalgia is a syndrome of chronic central sensitization with no known cure to date. What electroacupuncture can offer — as demonstrated by this and other studies — is significant reduction of pain intensity, improvement of pressure pain tolerance, and possibly modulation of central amplification mechanisms. The realistic therapeutic objective is to improve the patient’s quality of life and functionality, reducing the painful burden and dependence on long-standing pharmacotherapy.
Yes, especially those who have not responded adequately to conventional pharmacotherapy (duloxetine, pregabalin, milnacipran) or who present medication intolerance. Patients with comorbid anxiety and sleep disorder components also tend to benefit, given that medical acupuncture has demonstrated efficacy in these associated conditions. Assessment should be individualized by the physician, considering the sensitization profile, comorbidities, and patient expectations.
Founded in 1989 by physicians trained at the University of São Paulo (USP) and specialized in China, CEIMEC is a Brazilian national reference in the teaching and practice of medical acupuncture. With more than 3,000 physicians trained over 35 years, it collaborates with HC-FMUSP and is recognized by the Brazilian Medical College of Acupuncture (CMBA/AMB).
Learn More about this Topic
Related educational articles
Fibromyalgia: Why It Hurts Everywhere — and What Works
Understand fibromyalgia — a syndrome of chronic widespread pain, its central mechanisms, diagnosis, and multidisciplinary therapeutic approaches.
Central Sensitization: When the Nervous System Amplifies Pain
How the central nervous system 'learns' to feel more pain — wind-up, allodynia, and the role of neuroplasticity
How Acupuncture Works: Neurophysiologic Mechanisms
The science behind acupuncture: nociceptors, endogenous opioids, DPMS, inflammation, and neuroplasticity