Acupuncture Induces Divergent Alterations of Functional Connectivity within Conventional Frequency Bands: Evidence from MEG Recordings

Abstract

As an ancient Chinese healing modality which has gained increasing popularity in modern society, acupuncture involves stimulation with fine needles inserted into acupoints. Both traditional literature and clinical data indicated that modulation effects largely depend on specific designated acupoints. However, scientific representations of acupoint specificity remain controversial. In the present study, considering the new findings on the sustained effects of acupuncture and its time-varied temporal characteristics, we employed an electrophysiological imaging modality namely magnetoencephalography with a temporal resolution on the order of milliseconds. Taken into account the differential band-limited signal modulations induced by acupuncture, we sought to explore whether or not stimulation at Stomach Meridian 36 (ST36) and a nearby non-meridian point (NAP) would evoke divergent functional connectivity alterations within delta, theta, alpha, beta and gamma bands. Whole-head scanning was performed on 28 healthy participants during an eyes-closed no-task condition both preceding and following acupuncture. Data analysis involved calculation of band-limited power (BLP) followed by pair-wise BLP correlations. Further averaging was conducted to obtain local and remote connectivity. Statistical analyses revealed the increased connection degree of the left temporal cortex within delta (0.5–4 Hz), beta (13–30 Hz) and gamma (30–48 Hz) bands following verum acupuncture. Moreover, we not only validated the closer linkage of the left temporal cortex with the prefrontal and frontal cortices, but further pinpointed that such patterns were more extensively distributed in the ST36 group in the delta and beta bands compared to the restriction only to the delta band for NAP. Psychophysical results for significant pain threshold elevation further confirmed the analgesic effect of acupuncture at ST36. In conclusion, our findings may provide a new perspective to lend support for the specificity of neural expression underlying acupuncture.

Hypothalamus-Related Resting Brain Network Underlying Short-Term Acupuncture Treatment in Primary Hypertension

“…The eligibility criteria included (1) clinical diagnosis in line with WHO diagnostic criteria of essential hypertension: systolic blood pressure (SBP) ≥140 mmHg and diastolic blood pressure (DBP) ≥90 mmHg without antihypertensive drugs, two or more repeated measurements, normal BP now with the use of antihypertensive drugs but with a clear history of hypertension, and species and dose of antihypertensive medicine not changed or suspended or not taking antihypertensive drugs during the study period [8, 9]; (2) 30–75 years old; (3) without cerebral infarction history and without cerebral infarction by MRI preliminary screening; (4) without nervous system disease, mental disease, diabetes, or other serious illness; (5) no drug addiction history; (6) no MRI contraindication and acupuncture contraindication; (7) no acupuncture experience over the past year; (8) right-handed by Edinburgh handedness questionnaire [19]; (9) provision of informed consent. The exclusion criteria included (1) could not receive acupuncture; (2) any unsuitable situation in the study.…”

“…In the past two decades, converging evidence from fMRI studies has demonstrated that acupuncture stimulation can modulate neural activities in a wide cortical-subcortical network, particularly the limbic system [11–19]. In practice, the well-identified physical effects of acupuncture and its purported clinical efficacy also suggest that it helps maintain a homeostatic balance of the internal state within and across multiple brain systems.…”

Neurobiological Foundations of Acupuncture: The Relevance and Future Prospect Based on Neuroimaging Evidence

“…To further test our hypothesis, we also adopted an electrophysiological imaging modality, namely, magnetoencephalography with a more sensitive temporal resolution on the order of milliseconds. Our findings showed that verum acupuncture can increase the connection degree between the temporal cortex (amygdala and hippocampus) and prefrontal cortex within delta (0.5–4 Hz) and beta (13–30 Hz) bands, while such effect occurred only in the delta band for sham control [34]. …”

What is the Acupoint? A preliminary review of Acupoints

“…Acupuncture at specific acupoints of the stomach meridian was found to be superior to nonspecific acupoints and sham acupoint for FD patients . Furthermore, neuroimaging studies provided similar evidence for this theory .…”