Neuroimaging Decodes How Acupuncture Modulates Brain Networks

An integrative review published in Frontiers in Human Neurosciencesynthesizes the neuroimaging literature on the brain mechanisms of acupuncture, integrating data from functional magnetic resonance imaging (fMRI), electroencephalography (EEG), and positron emission tomography (PET). The work, conducted by researchers from Heilongjiang University of Traditional Chinese Medicine, proposes a unified framework that connects the peripheral stimulation of the needle to measurable changes in brain networks — explaining how medical acupuncture produces clinical effects that go beyond the application site.

Brain networks that respond to acupuncture

The fMRI studies reviewed identify consistent patterns of cerebral activation and deactivation after acupuncture. The limbic system — including amygdala and hippocampus — responds significantly to acupuncture stimulation, which underpins the effects on anxiety, memory, and emotional processing of pain. The default mode network (DMN), which is pathologically hyperactivated in chronic pain conditions such as fibromyalgia and chronic low back pain, has been associated, in neuroimaging studies, with specific modulation by acupuncture — with connectivity alterations that correlate with clinical improvement in some studies. Spinal and supraspinal nociceptive pathways — including thalamus, somatosensory córtex, and insula — also exhibit characteristic responses that explain the analgesia.

The methodologic challenge: what the sham reveals

One of the most provocative findings of the review is that sham procedures — retractable needles or inactive laser applied at real acupoints or at non-acupuncture points — elicit cerebral activations similar to those of active acupuncture, although of attenuated magnitude. The authors interpret this phenomenon as evidence of two superimposed components: a specific effect of the acupoints and the manipulation of the needle (greater in the active group), and a non-specific effect of expectation and general sensory response (present in both groups). The clinical implication is that part of the benefit of acupuncture derives from specific point mechanisms, justifying specialized medical training in the precise selection and manipulation of acupoints.

The convergence of fMRI, EEG, and PET data presented in this review strengthens the understanding of acupuncture as a neuromodulatory intervention with identifiable and measurable mechanisms. The capacity to alter the connectivity of networks such as the DMN — hyperactivated in chronic pain — suggests that medical acupuncture may interact with these brain networks, although the extent and durability of this reorganization are still subject of active investigation, complementary to pharmacologic and psychological approaches in the management of chronic pain conditions.