Neural encoding of acupuncture needling sensations: evidence from a FMRI study

Objectivization study of acupuncture Deqi and brain modulation mechanisms: a review

Deqi is an important prerequisite for acupuncture to achieve optimal efficacy. Chinese medicine has long been concerned with the relationship between Deqi and the clinical efficacy of acupuncture. However, the underlying mechanisms of Deqi are complex and there is a lack of systematic summaries of objective quantitative studies of Deqi. Acupuncture Deqi can achieve the purpose of treating diseases by regulating the interaction of local and neighboring acupoints, brain centers, and target organs. At local and neighboring acupoints, Deqi can change their tissue structure, temperature, blood perfusion, energy metabolism, and electrophysiological indicators. At the central brain level, Deqi can activate the brain regions of the thalamus, parahippocampal gyrus, postcentral gyrus, insular, middle temporal gyrus, cingulate gyrus, etc. It also has extensive effects on the limbic-paralimbic-neocortical-network and default mode network. The brain mechanisms of Deqi vary depending on the acupuncture techniques and points chosen. In addition, Deqi 's mechanism of action involves correcting abnormalities in target organs. The mechanisms of acupuncture Deqi are multi-targeted and multi-layered. The biological mechanisms of Deqi are closely related to brain centers. This study will help to explore the mechanism of Deqi from a local-central-target-organ perspective and provide information for future clinical decision-making.

A systematic review and coordinate-based meta-analysis of fMRI studies on acupuncture at LR 3

Objectives

The acupoint LR3 (Taichong) is frequently utilized in clinical acupuncture. However, its underlying neural mechanisms remain not fully elucidated, with speculations suggesting its close association with specific brain activity patterns.

Methods

A comprehensive literature search was undertaken across several online databases, such as PubMed, Web of Science, Embase, Cochrane Library, CNKI (China National Knowledge Infrastructure), Wanfang Database, VIP Database, and the Chinese Biomedical Database. Two independent researchers handled the study selection, quality assessment, and data extraction processes. Using the seed-based d-mapping meta-analysis approach, we evaluated the brain regions activated by LR3 acupuncture in healthy subjects. Subsequent subgroup analysis was stratified by fMRI types, and regression analyses were performed considering the duration of acupuncture, depth of needle insertion, and needle diameter. The identified active brain regions were then intricately projected onto large-scale functional networks.

Results

A total of 10 studies met the criteria for inclusion, encompassing 319 healthy right-handed participants. The meta-analysis indicates that acupuncture at the LR3 activates regions such as the right postcentral gyrus, left thalamus, left middle frontal gyrus, and right superior frontal gyrus. Additionally, meta-regression analysis highlights that increased acupuncture duration correlates with progressively intensified activation of the right superior frontal gyrus. Subgroup analysis posits that variations in the type of fMRI employed might account for heterogeneity in the pooled results. Concurrently, functional network analysis identifies the primary activated regions as aligning with the Basal ganglia network, Auditory network, Left executive control network, Posterior salience network, Right executive control network, and Sensorimotor networks.

Conclusion

Acupuncture at the LR3 in healthy subjects selectively activates brain regions linked to pain perception, emotional processing, and linguistic functions. Extending the needle retention duration intensifies the activation of the right superior frontal gyrus. These findings enrich our comprehension of the neurobiological underpinnings of acupuncture's role in pain mitigation and emotional regulation.

Frequency-Specific Blood Oxygen Level Dependent Oscillations Associated With Pain Relief From Ankle Acupuncture in Patients With Chronic Low Back Pain

Objective: Recent advances in brain imaging have deepened our knowledge of the neural activity in distinct brain areas associated with acupuncture analgesia. However, there has not been conclusive research into the frequency-specific resting-state functional changes associated with acupuncture analgesia in patients with chronic pain. Here, we aimed to characterize changes across multiple frequencies of resting-state cortical activity associated with ankle acupuncture stimulation (AAS) in patients with chronic low back pain (CLBP) and healthy controls.

Methods: Twenty seven patients with CLBP and Twenty five age- and gender-matched healthy volunteers were enrolled in the study. Participants received tactile sham acupuncture (TSA) and AAS, respectively. The whole-brain amplitude of low-frequency fluctuation (ALFF) in the range 0.01–0.25 Hz was assessed for changes associated with each intervention. Further, a visual analog scale (VAS) was used to collect subjective measures of pain intensity in patients. Linear mixed-effect modeling (LME) was used to examine the mean ALFF values of AAS and TSA between patients and healthy controls.

Results: The ALFF was modulated in the default mode network (an increase in the medial prefrontal cortex, and a decrease in the cerebellum/posterior ingulate/parahippocampus, P < 0.01, corrected) in both patients and controls. Decreased ALFF in the bilateral insular was frequency-dependent. Modulations in the cerebellum and right insular were significantly correlated with VAS pain score after AAS (P < 0.01).

Conclusion: Hence, frequency-specific resting-state activity in the cerebellum and insular was correlated to AAS analgesia. Our frequency-specific analysis of ALFF may provide novel insights related to pain relief from acupuncture.

Fascia Mobility, Proprioception, and Myofascial Pain

The network of fasciae is an important part of the musculoskeletal system that is often overlooked. Fascia mobility, especially along shear planes separating muscles, is critical for musculoskeletal function and may play an important, but little studied, role in proprioception. Fasciae, especially the deep epimysium and aponeuroses, have recently been recognized as highly innervated with small diameter fibers that can transmit nociceptive signals, especially in the presence of inflammation. Patients with connective tissue hyper- and hypo-mobility disorders suffer in large number from musculoskeletal pain, and many have abnormal proprioception. The relationships among fascia mobility, proprioception, and myofascial pain are largely unstudied, but a better understanding of these areas could result in improved care for many patients with musculoskeletal pain.

The Japanese Version of the Massachusetts General Hospital Acupuncture Sensation Scale: A Validation Study

Acupuncture sensations are considered essential in producing the treatment effect of acupuncture. The Massachusetts General Hospital Acupuncture Sensation Scale (MASS) is a frequently used scale in acupuncture research to measure acupuncture sensations. We translated the MASS into Japanese (Japanese MASS) based on Beaton's guidelines. 30 acupuncturists evaluated the relevancy and meaning of the 12 descriptors included in the Japanese MASS. The content validity ratios for 10 of the 12 descriptors were 0.33 or greater. 42 healthy subjects then evaluated acupuncture sensations evoked by manual acupuncture at LI4 using the Japanese MASS. Cronbach's alpha was 0.86. The correlation coefficient of total MASS scores and total Short Form McGill Pain Questionnaire scores and MASS indices and sensory visual analogue scores were 0.78 and 0.80, respectively. Factor analysis loaded the 12 descriptors onto two meaningful factors. This study demonstrated that the Japanese MASS has good reliability, content validity, criterion-related validity, and construct validity. Therefore, the Japanese MASS is a valid and reliable instrument for use with Japanese populations.

Ipsilateral Putamen and Insula Activation by Both Left and Right GB34 Acupuncture Stimulation: An fMRI Study on Healthy Participants

The modulatory effects on the brain during right versus left side acupuncture stimulation of the same acupuncture point have been a subject of controversy. For clarification of this important methodological issue, the present study was designed to compare the blood oxygen level-dependent responses of acupuncture stimulation on the right versus left Yanglingquan (GB34). Twenty-two healthy subjects received right or left GB34 acupuncture. Our results show that acupuncture on the left GB34 induced neural responses in the left putamen, caudate body, insula, postcentral gyrus, claustrum, right and left thalamus, right middle frontal gyrus, hypothalamus, and subthalamic nucleus. Acupuncture on the right GB34 induced neural responses in the right middle frontal gyrus, inferior parietal lobule, thalamus, putamen, lateral globus pallidus, medial globus pallidus, and insula. Interestingly, the putamen and insula were ipsilaterally activated by acupuncture on either the left or right GB34; therefore, they seem to be the main target areas affected by GB34 acupuncture. This is the first reported functional magnetic resonance imaging study directly comparing needling on the right and left GB34. Although more replication studies are needed, our preliminary results prove that acupuncture has different modulatory effects on the brain when performed on the right versus left side.

More than DeQi: Spatial Patterns of Acupuncture-Induced Bodily Sensations

Acupuncture uses needles to stimulate certain parts of the body, inducing a specific sensation, termed DeQi, which regard as essential for acupuncture's therapeutic effect. Here, we used the newly developed tool, bodily sensation mapping, to investigate the spatial configuration of acupuncture-induced sensations throughout the body. Twenty-five participants randomly received acupuncture stimulation or tactile stimulation using a von Frey filament at four different acupoints (HT7, PC6, ST36, and SP10) on the left side of the body. Subjects evaluated the characteristics of DeQi sensations and marked the areas of induced sensations on a body outline. We compared the psychophysical responses of DeQi sensations and visualized the spatial patterns of these sensations using statistical parametric mapping. We found greater intensity of DeQi sensations following acupuncture stimulation compared with tactile stimulation, with relatively small differences among the four acupoints. The sensation maps exhibited similar spatial patterns for acupuncture and tactile stimulation in the areas close to the stimulated sites. However, acupuncture was associated with additional sensations in areas remote from the stimulated sites. This study demonstrates that acupuncture stimulation produces greater DeQi sensations than tactile stimulation and results in the spreading of sensations to areas remote from the stimulus sites. Investigating the spatial patterns of acupuncture-induced sensations may be crucial for understanding the underlying mechanisms of acupuncture.

Sustained Effects of Acupuncture Stimulation Investigated with Centrality Mapping Analysis

Acupuncture can have instant and sustained effects, however, its mechanisms of action are still unclear. Here, we investigated the sustained effect of acupuncture by evaluating centrality changes in resting-state functional magnetic resonance imaging after manually stimulating the acupuncture point ST36 at the lower leg or two control point locations (CP1 same dermatome, CP2 different dermatome). Data from a previously published experiment evaluating instant BOLD effects and S2-seed-based resting state connectivity was re-analyzed using eigenvector centrality mapping and degree centrality mapping. These data-driven methods might add new insights into sustained acupuncture effects on both global and local inter-region connectivity (centrality) by evaluating the summary of connections of every voxel. We found higher centrality in parahippocampal gyrus and middle temporal gyrus after ST36 stimulation in comparison to the two control points. These regions are positively correlated to major hubs of the default mode network, which might be the primary network affected by chronic pain. The stronger integration of both regions within the whole-brain connectome after stimulation of ST36 might be a potential contributor to pain modulation by acupuncture. These findings highlight centrality mapping as a valuable analysis for future imaging studies investigating clinically relevant outcomes associated with physiological response to acupuncture stimulation.

CLINICAL TRIAL REGISTRATION

NCT01079689, ClinicalTrials.gov.

The Status of the Quality Control in Acupuncture-Neuroimaging Studies

Using neuroimaging techniques to explore the central mechanism of acupuncture gains increasing attention, but the quality control of acupuncture-neuroimaging study remains to be improved. We searched the PubMed Database during 1995 to 2014. The original English articles with neuroimaging scan performed on human beings were included. The data involved quality control including the author, sample size, characteristics of the participant, neuroimaging technology, and acupuncture intervention were extracted and analyzed. The rigorous inclusion and exclusion criteria are important guaranty for the participants' homogeneity. The standard operation process of acupuncture and the stricter requirement for acupuncturist play significant role in quality control. More attention should be paid to the quality control in future studies to improve the reproducibility and reliability of the acupuncture-neuroimaging studies.

Exploring Neural Correlates of Different Dimensions in Drug Craving Self-Reports among Heroin Dependents

INTRODUCTION

Drug craving could be described as a motivational state which drives drug dependents towards drug seeking and use. Different types of self-reports such as craving feeling, desire and intention, wanting and need, imagery of use, and negative affect have been attributed to this motivational state. By using subjective self-reports for different correlates of drug craving along with functional neuroimaging with cue exposure paradigm, we investigated the brain regions that could correspond to different dimensions of subjective reports for heroin craving.

METHODS

A total of 25 crystalline-heroin smokers underwent functional magnetic resonance imaging (fMRI), while viewing heroin-related and neutral cues presented in a block-design task. During trial intervals, subjects verbally reported their subjective feeling of cue induced craving (CIC). After fMRI procedure, participants reported the intensity of their "need for drug use" and "drug use imagination" on a 0-100 visual analog scale (VAS). Afterwards, they completed positive and negative affect scale (PANAS) and desire for drug questionnaire (DDQ) with 3 components of "desire and intention to drug use," "negative reinforcement," and "loss of control."

RESULTS

The study showed significant correlation between "subjective feeling of craving" and activation of the left and right anterior cingulate cortex, as well as right medial frontal gyrus. Furthermore, the "desire and intention to drug use" was correlated with activation of the left precentral gyrus, left superior frontal gyrus, and left middle frontal gyrus. Subjects also exhibited significant correlation between the "need for drug use" and activation of the right inferior temporal gyrus, right middle temporal gyrus, and right parahippocampal gyrus. Correlation between subjective report of "heroin use imagination" and activation of the cerebellar vermis was also observed. Another significant correlation was between the "negative affect" and activation of the left precuneus, right putamen, and right middle temporal gyrus.

DISCUSSION

This preliminary study proposes different neural correlates for various dimensions of subjective craving self-reports. It could reflect multidimensionality of cognitive functions corresponding with drug craving. These cognitive functions could represent their motivational and affective outcomes in a single item "subjective craving feeling" or in self-reports with multiple dissociable items, such as intention, need, imagination, or negative feeling. The new psychological models of drug craving for covering various dimensions of subjective craving self-reports based on their neurocognitive correspondence could potentially modify craving assessments in addiction medicine.

Does functional MRI detect activation in white matter? A review of emerging evidence, issues, and future directions

Functional magnetic resonance imaging (fMRI) is a non-invasive technique that allows for visualization of activated brain regions. Until recently, fMRI studies have focused on gray matter. There are two main reasons white matter fMRI remains controversial: (1) the blood oxygen level dependent (BOLD) fMRI signal depends on cerebral blood flow and volume, which are lower in white matter than gray matter and (2) fMRI signal has been associated with post-synaptic potentials (mainly localized in gray matter) as opposed to action potentials (the primary type of neural activity in white matter). Despite these observations, there is no direct evidence against measuring fMRI activation in white matter and reports of fMRI activation in white matter continue to increase. The questions underlying white matter fMRI activation are important. White matter fMRI activation has the potential to greatly expand the breadth of brain connectivity research, as well as improve the assessment and diagnosis of white matter and connectivity disorders. The current review provides an overview of the motivation to investigate white matter fMRI activation, as well as the published evidence of this phenomenon. We speculate on possible neurophysiologic bases of white matter fMRI signals, and discuss potential explanations for why reports of white matter fMRI activation are relatively scarce. We end with a discussion of future basic and clinical research directions in the study of white matter fMRI.

Local Anesthesia at ST36 to Reveal Responding Brain Areas to deqi

Background. Development of non-deqi control is still a challenge. This study aims to set up a potential approach to non-deqi control by using lidocaine anesthesia at ST36. Methods. Forty healthy volunteers were recruited and they received two fMRI scans. One was accompanied with manual acupuncture at ST36 (DQ group), and another was associated with both local anesthesia and manual acupuncture at the same acupoint (LA group). Results. Comparing to DQ group, more than 90 percent deqi sensations were reduced by local anesthesia in LA group. The mainly activated regions in DQ group were bilateral IFG, S1, primary motor cortex, IPL, thalamus, insula, claustrum, cingulate gyrus, putamen, superior temporal gyrus, and cerebellum. Surprisingly only cerebellum showed significant activation in LA group. Compared to the two groups, bilateral S1, insula, ipsilateral IFG, IPL, claustrum, and contralateral ACC were remarkably activated. Conclusions. Local anesthesia at ST36 is able to block most of the deqi feelings and inhibit brain responses to deqi, which would be developed into a potential approach for non-deqi control. Bilateral S1, insula, ipsilateral IFG, IPL, claustrum, and contralateral ACC might be the key brain regions responding to deqi.

The holistic effects of acupuncture treatment

Traditional Chinese Medicine (TCM), as a complex medical science which reflects philosophical principles and embodies large dialectical thought, is used to place the human body into a large system for observation. Acupuncture as a vital part of TCM, has been practiced to treat various diseases and symptoms. However, acupuncture is also facing severe challenges resulted from insufficient modern scientific research. Nowadays, the holistic effects of acupuncture can be researched by some modern approaches, such as the systems biology and fMRI technique. It is believed that having a better understand will greatly promote acupuncture research and be beneficial to scientization and modernization of acupuncture.