Neural mechanisms of acupuncture as revealed by fMRI studies
He et al. · Autonomic Neuroscience: Basic and Clinical · 2015
Evidence Level
MODERATEOBJECTIVE
To review fMRI studies on acupuncture to understand the underlying neural mechanisms
WHO
2,263 participants across 82 studies (61 with healthy volunteers)
DURATION
Review of studies published between January 2008 and 2015
POINTS
ST-36 most studied, along with PC-6, GB-37, LI-4, LR-3, among others
🔬 Study Design
Healthy volunteers
n=1875
Manual acupuncture, electroacupuncture, or laser
Patients
n=388
Therapeutic acupuncture
📊 Results in numbers
Studies included in the review
Total participants
Studies with block design
Median subjects per study
Percentage highlights
📊 Outcome Comparison
Type of Experimental Design
This study analyzed how acupuncture affects the brain using MRI. The researchers found that acupuncture activates several brain networks important for pain processing, emotions, and cognition. This helps scientifically explain how acupuncture works in the body.
Article summary
Plain-language narrative summary
This comprehensive review analyzed 82 functional magnetic resonance imaging (fMRI) studies on acupuncture published between 2008 and 2015, involving 2,263 participants. The objective was to understand the neural mechanisms by which acupuncture produces its therapeutic effects. The studies primarily included healthy volunteers (75%), with a median of 28 participants per study. The researchers investigated different acupuncture modalities, including manual acupuncture, electroacupuncture, transcutaneous electrical acupoint stimulation (TEAS), and laser acupuncture.
The most frequently studied points were ST-36 (Zusanli), PC-6 (Neiguan), GB-37 (Guangming), and LI-4 (Hegu). The review revealed that acupuncture induces hemodynamic changes in a broad cortico-subcortical network, with activation of somatosensory areas and deactivation of the limbic-paralimbic-neocortical network. Studies on acupoint specificity showed controversial results. Some demonstrated that specific points activate brain regions related to their traditional therapeutic indications, such as GB-37 activating the visual cortex and PC-6 modulating the insula and cerebellum for nausea.
Other studies found no significant differences between true acupoints and controls. The deqi sensation was associated with sensorimotor activation and deactivation of the default mode network (DMN). Different acupuncture modalities produced distinct patterns of brain activation, with manual acupuncture predominantly affecting the DMN and electroacupuncture modulating more extensive sensorimotor networks. Studies in patients showed that acupuncture can modulate dysfunctional brain networks, as in Parkinson's disease (activation of the basal ganglia-thalamic-cortical circuit), stroke (modulation of motor networks and DMN), and Alzheimer's disease (improved connectivity in memory regions).
The limitations identified include heterogeneity in experimental methods, small sample sizes, variability in acupuncture administration, and difficulties in establishing appropriate controls. Many studies used single stimulation at isolated points, differing from traditional clinical practice. The authors highlighted the need to standardize methodologies, increase sample sizes, and develop experimental designs that better reflect the actual clinical use of acupuncture. The findings suggest that acupuncture works through the modulation of multiple brain networks involved in pain, emotion, and cognition processing, providing a neuroscientific basis for its therapeutic effects.
Strengths
- 1Comprehensive review with a large number of studies and participants
- 2Detailed analysis of different modalities and experimental designs
- 3Clear identification of controversies and methodological limitations
- 4Solid scientific basis for the neural mechanisms of acupuncture
Limitations
- 1Significant heterogeneity among reviewed studies
- 2Majority of studies in healthy volunteers vs. real patients
- 3Small sample sizes in individual studies
- 4Lack of standardization in acupuncture protocols and controls
Expert Commentary
Prof. Dr. Hong Jin Pai
PhD in Sciences, University of São Paulo
▸ Clinical Relevance
Understanding the neural mechanisms of acupuncture has shifted from academic curiosity to becoming a central argument for justifying its integration into the contemporary medical therapeutic arsenal. This review, by consolidating 82 fMRI studies involving more than 2,200 participants, offers the clinician a functional map of the brain effects of acupuncture that supports concrete therapeutic decisions. Patients with chronic pain, stroke sequelae, Parkinson's disease, and conditions with cognitive dysfunction are among those who benefit most from this mechanistic perspective. By demonstrating that acupuncture modulates cortico-subcortical networks, including the default mode network and limbic circuits, the work provides a neurophysiological foundation for its use in conditions where pain centralization and the emotional component are decisive — such as fibromyalgia, chronic low back pain, and tension-type headache — favoring its rational combination with drugs that act on the central nervous system.
▸ Notable Findings
The most striking finding of this review is the functional dissociation observed in the brain during acupuncture: while somatosensory areas are activated, the limbic-paralimbic-neocortical network is systematically deactivated. This pattern — practically the inverse of what is observed in chronic pain, where this same network is hyperactive — suggests a mechanism of functional rebalancing with biological coherence. The deqi sensation emerges as a relevant mediating variable, associated with sensorimotor activation and suppression of the default mode network, giving neural substrate to the clinical perception that sessions with adequate deqi produce better responses. Also noteworthy is the functional specificity of points such as GB-37 and PC-6, whose activations in the visual cortex and insula, respectively, are consistent with their traditional indications — an alignment between classical paradigm and neuroimaging that rarely articulates so clearly in the literature.
▸ From My Experience
In my practice at the Pain Center of HC-FMUSP, these neuroimaging findings resonate with what we have observed empirically for decades. Patients with centralized chronic pain — those in whom the limbic component dominates the picture — respond particularly consistently to acupuncture, and the explanation through modulation of the default mode network offers the resident a conceptual framework to identify this responder profile. I typically see the first signs of response between the third and fifth sessions, with clinical stabilization around eight to twelve sessions in cases of moderate chronic pain. In neurological patients, such as post-stroke patients with spasticity or parkinsonians with rigidity and slowness, we combine electroacupuncture with motor physical therapy, precisely because fMRI data suggest that this modality more broadly modulates the sensorimotor networks. The deqi sensation as a response marker is something I emphasize in the training of acupuncturist physicians: it is not ritual, it is physiology.
Full original article
Read the full scientific study
Autonomic Neuroscience: Basic and Clinical · 2015
DOI: 10.1016/j.autneu.2015.03.006
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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