Differences in cortical response to acupressure and electroacupuncture stimuli

Harvard Medical School, Martinos Center for Biomedical Imaging, Charlestown, MA 02129, USA.
BMC Neuroscience (Impact Factor: 2.67). 07/2011; 12(1):73. DOI: 10.1186/1471-2202-12-73
Source: PubMed


FMRI studies focus on sub-cortical effects of acupuncture stimuli. The purpose of this study was to assess changes in primary somatosensory (S1) activity over the course of different types of acupuncture stimulation. We used whole head magnetoencephalography (MEG) to map S1 brain response during 15 minutes of electroacupuncture (EA) and acupressure (AP). We further assessed how brain response changed during the course of stimulation.
Evoked brain response to EA differed from AP in its temporal dynamics by showing clear contralateral M20/M30 peaks while the latter demonstrated temporal dispersion. Both EA and AP demonstrated significantly decreased response amplitudes following five minutes of stimulation. However, the latency of these decreases were earlier in EA (~30 ms post-stimulus) than AP (> 100 ms). Time-frequency responses demonstrated early onset, event related synchronization (ERS), within the gamma band at ~70-130 ms and the theta band at ~50-200 ms post-stimulus. A prolonged event related desynchronization (ERD) of alpha and beta power occurred at ~100-300 ms post-stimulus. There was decreased beta ERD at ~100-300 ms over the course of EA, but not AP.
Both EA and AP demonstrated conditioning of SI response. In conjunction with their subcortical effects on endogenous pain regulation, these therapies show potential for affecting S1 processing and possibly altering maladaptive neuroplasticity. Thus, further investigation in neuropathic populations is needed.

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    • "Such a methodological and analysis approach has been taken advantage of in MEG studies of acupuncture using electroacupuncture or acupressure where the stimulus onset times are able to be measured since these stimuli are initiated electronically. The results of such investigations have revealed mappings onto the primary somatosensory cortex (Dhond et al., 2008; Witzel et al., 2011) with alterations in event related synchronizations/desynchronizations in various frequency bands (Witzel et al., 2011). In contrast to electroacupuncture or acupressure, when administrating manual insertive acupuncture the onset time for each needling stimulus is not discernible due to the inherent complex nature of the applied stimulus. "
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    ABSTRACT: Magnetoencephalography (MEG) enables non-invasive recording of neuronal activity, with reconstruction methods providing estimates of underlying brain source locations and oscillatory dynamics from externally recorded neuromagnetic fields. The aim of our study was to use MEG to determine the effect of manual acupuncture on neuronal oscillatory dynamics. A major problem in MEG investigations of manual acupuncture is the absence of onset times for each needle manipulation. Given that beamforming (spatial filtering) analysis is not dependent upon stimulus-driven responses being phase-locked to stimulus onset, we postulated that beamforming could reveal source locations and induced changes in neuronal activity during manual acupuncture. In a beamformer analysis, a two-minute period of manual acupuncture needle manipulation delivered to the ipsilateral right LI-4 (Hegu) acupoint was contrasted with a two-minute baseline period. We considered oscillatory power changes in the theta (4-8 Hz), alpha (8-13 Hz), beta (13-30 Hz), and gamma (30-100 Hz) frequency bands. We found significant decreases in beta band power in the contralateral primary somatosensory cortex and superior frontal gyrus (SFG). In the ipsilateral cerebral hemisphere, we found significant power decreases in beta and gamma frequency bands in only the SFG. No significant power modulations were found in theta and alpha bands. Our results indicate that beamforming is a useful analytical tool to reconstruct underlying neuronal activity associated with manual acupuncture. Our main finding was of beta power decreases in primary somatosensory cortex and SFG, which opens up a line of future investigation regarding whether this contributes toward an underlying mechanism of acupuncture.
    Frontiers in Human Neuroscience 11/2012; 6:303. DOI:10.3389/fnhum.2012.00303 · 3.63 Impact Factor
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    • "Test for overall effect: Z = 2.15 (p = 0.03) Fig. 2. Comparison of acupressure versus sham acupressure in posttreatment sleep questionnaire score. did at the limbic system, such as the parahippocampal gyrus and the anterior cingulate cortex [59] [60]. "
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    ABSTRACT: Previous randomized controlled trials (RCTs) have shown that acupuncture may be efficacious for insomnia. Instead of needling, acupressure, reflexology, and auricular acupressure are procedures involving physical pressure on acupoints or reflex areas. These variants of acupuncture are gaining popularity, perhaps due to their non-invasive nature. A systematic review has therefore been conducted to examine their efficacy and safety for insomnia. Two independent researchers searched five English and 10 Chinese databases from inception to May 2010. Forty RCTs were identified for analysis. Only 10 studies used sham controls, four used double-blind design, nine studies scored three or more by the Jadad scale, and all had at least one domain with high risk of bias. Meta-analyses of the moderate-quality RCTs found that acupressure as monotherapy fared marginally better than sham control. Studies that compared auricular acupressure and sham control showed equivocal results. It was also found that acupressure, reflexology, or auricular acupressure as monotherapy or combined with routine care was significantly more efficacious than routine care or no treatment. Owing to the methodological limitations of the studies and equivocal results, the current evidence does not allow a clear conclusion on the benefits of acupressure, reflexology, and auricular acupressure for insomnia.
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    ABSTRACT: The theory of acupoint specificity is the basis for elucidating the actions of acupoints as employed in clinical practice. Acupoint specificity has become a focus of attention in international research efforts by scholars in the areas of acupuncture and moxibustion. In 2006, the Chinese Ministry of Science approved and initiated the National Basic Research Program (973 Program), one area of which was entitled Basic Research on Acupoint Specificity Based on Clinical Efficacy. Using such approaches as data mining, evidence-based medicine, clinical epidemiology, neuroimaging, molecular biology, neurophysiology, and metabolomics, fruitful research has been conducted in the form of literature research, clinical assessments, and biological studies. Acupoint specificity has been proved to exist, and it features meridian-propagated, relative, persistent, and conditional effects. Preliminarily investigations have been made into the biological basis for acupoint specificity.
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