Resting-State fMRI in Studies of Acupuncture
Li et al. · Evidence-Based Complementary and Alternative Medicine · 2021
Evidence Level
MODERATEOBJECTIVE
To review the application of resting-state fMRI in studying the neural mechanisms of acupuncture
WHO
Multiple studies with different populations and health conditions
DURATION
Review of studies from the past 10 years (2010-2020)
POINTS
LR-3, ST-36, GB-34, LI-4, among other classical points
🔬 Study Design
Narrative review
n=0
Analysis of multiple fMRI studies in acupuncture
📊 Results in numbers
Number of applications identified
Brain networks modulated
Point specificity
Differences between real vs. sham acupuncture
📊 Outcome Comparison
Regional brain activity
This review shows that acupuncture produces specific and measurable changes in brain activity, which can be observed through magnetic resonance imaging examinations. The results help to scientifically explain how acupuncture works in the brain.
Article summary
Plain-language narrative summary
This comprehensive review examines how resting-state functional magnetic resonance imaging (rs-fMRI) has been used to understand the neural mechanisms of acupuncture over the past 10 years. The authors systematically analyzed studies that investigated different aspects: comparison between acupuncture points, needling methods, stimulation intensities, and specific clinical applications. The review reveals five main applications of rs-fMRI in acupuncture research: investigation of therapeutic mechanisms of action, visual evidence for disease diagnosis and treatment, evaluation of efficacy, understanding of the physiologic mechanisms of acupoint stimulation, and specific visualization of point effects. The results demonstrate that different acupoints produce distinct patterns of brain connectivity and local activity.
Individual points such as LR-3, ST-36, and GB-34 have shown specific effects on networks related to cognition, emotion, and pain processing. Point combinations produced broader activation than single points. The limbic system and subcortical areas emerged as important centers following acupuncture. Comparisons between real and sham acupuncture revealed that real acupuncture significantly increases connectivity in networks such as the default mode network (DMN), periaqueductal gray matter (PAG), posterior cingulate cortex (PCC), and the pain matrix, while sham acupuncture influences fewer functional areas.
Differences were found between contralateral and ipsilateral acupuncture, and significant individual effects were observed. Different methods (manual acupuncture vs. electroacupuncture) and stimulation intensities produced varying degrees of changes in brain functional connectivity. In clinical application, rs-fMRI demonstrated utility in the study of various conditions: neurologic diseases such as Alzheimer disease and depression showed modulation of limbic systems and cognitive networks; chronic pain conditions revealed regulation of the default mode, salience, central executive, and sensorimotor networks; other conditions such as hypertension, premenstrual syndrome, and substance dependence showed specific patterns of brain modulation.
Rs-fMRI technology offers a valuable technical platform for establishing specific biomarkers for diseases and evaluating the therapeutic effects of acupuncture. The ability to observe spontaneous neural activities at multiple scales contributes to mapping brain organization and mechanisms. This robust scientific evidence helps to validate the effects of acupuncture and provides a neuroscientific basis for its clinical application.
Strengths
- 1Comprehensive review of 10 years of literature
- 2Systematic analysis of multiple applications of rs-fMRI
- 3Robust evidence of point specificity in acupuncture
- 4Clear demonstration of differences between real and sham acupuncture
Limitations
- 1Relatively small sample sizes in the included studies
- 2Methodologic heterogeneity between studies
- 3Need for more standardized studies
- 4Technical limitations of rs-fMRI technology itself
Expert Commentary
Prof. Dr. Hong Jin Pai
PhD in Sciences, University of São Paulo
▸ Clinical Relevance
Resting-state functional neuroimaging represents a qualitative advance in understanding the mechanisms by which acupuncture produces sustained therapeutic effects—those that persist well beyond the needling session. What this ten-year literature review consolidates is particularly relevant for the clinician who needs to engage with skeptical patients or with colleagues in other specialties: acupuncture measurably and specifically modifies brain networks involved in pain processing, emotional regulation, and cognitive control. Points such as LR-3, ST-36, and GB-34, canonically associated with distinct indications in traditional Chinese medicine, demonstrate different patterns of functional connectivity—which lends neuroscientific support to the rationale of point-selection protocols. For the physician treating chronic pain, depression, or neurologic diseases, this evidence underpins the therapeutic choice beyond clinical empiricism.
▸ Notable Findings
Among the most noteworthy findings is the confirmation that real and sham acupuncture produce distinct neural patterns detectable by rs-fMRI—a robust argument against the hypothesis that the effects of acupuncture are reducible to expectation or a nonspecific response. Real acupuncture significantly increases connectivity in networks such as the default mode network, periaqueductal gray matter, and the pain matrix, structures directly implicated in descending mechanisms of pain modulation. The emergence of the limbic system and subcortical areas as response centers after acupuncture is consistent with the clinical effects observed in conditions such as depression, premenstrual syndrome, and chemical dependence. Equally relevant is the finding that point combinations produce broader activation than isolated points, which has direct implications for the construction of therapeutic protocols.
▸ From My Experience
In my practice at the Pain Center of HC-FMUSP, I have long perceived that the response to acupuncture in patients with chronic pain is not limited to the session—something persists, accumulates, and it is exactly this cumulative effect that rs-fMRI is beginning to map. I usually observe the first consistent clinical responses between the third and fifth sessions, with consolidation around eight to twelve sessions for conditions such as chronic low back pain and fibromyalgia. The profile of patient that responds best, in my experience, is one without extreme chronification of pain behavior and with some functional reserve of the central nervous system—which makes sense in light of what neuroimaging reveals about network plasticity. I routinely combine acupuncture with motor physical therapy and, when indicated, with centrally acting antidepressants, because the modulated networks overlap. Patients with severe cognitive impairment or on multiple psychotropic drugs at high doses tend to respond less predictably—something that now finds a correlate in the documented patterns of connectivity.
Full original article
Read the full scientific study
Evidence-Based Complementary and Alternative Medicine · 2021
DOI: 10.1155/2021/6616060
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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