Modulation of cerebellar activities by acupuncture stimulation: evidence from fMRI study

The salient characteristics of the central effects of acupuncture needling: limbic-paralimbic-neocortical network modulation

Human and animal studies suggest that acupuncture produces many beneficial effects through the central nervous system. However, the neural substrates of acupuncture actions are not completely clear to date. fMRI studies at Hegu (LI4) and Zusanli (ST36) indicated that the limbic system may play an important role for acupuncture effects. To test if this finding applies to other major classical acupoints, fMRI was performed on 10 healthy adults during manual acupuncture at Taichong (LV3), Xingjian (LV2), Neiting (ST44), and a sham point on the dorsum of the left foot. Although certain differences could be observed between real and sham points, the hemodynamic response (BOLD signal changes) and psychophysical response (sensory experience) to acupuncture were generally similar for all four points. Acupuncture produced extensive deactivation of the limbic-paralimbic-neocortical system. Clusters of deactivated regions were seen in the medial prefrontal cortex (frontal pole, pregenual cingulate), the temporal lobe (amygdala, hippocampus, and parahippocampus) and the posterior medial cortex (precuneus, posterior cingulate). The sensorimotor cortices (somatosensory cortices, supplementary motor cortex), thalamus and occasional paralimbic structures such as the insula and anterior middle cingulate cortex showed activation. Our results provide additional evidence in support of previous reports that acupuncture modulates the limbic-paralimbic-neocortical network. We hypothesize that acupuncture may mediate its antipain, antianxiety, and other therapeutic effects via this intrinsic neural circuit that plays a central role in the affective and cognitive dimensions of pain as well as in the regulation and integration of emotion, memory processing, autonomic, endocrine, immunological, and sensorimotor functions.

Brain areas involved in acupuncture treatment on functional dyspepsia patients: a PET-CT study

Neuroimaging studies on brain responses to acupuncture stimulations have received considerable attention recently. The majority of these studies are centered on healthy controls (HC) and neuropathy, while little work has addressed other disorders. This study aimed to investigate the influence of acupuncture stimulations on brain activities in functional dyspepsia (FD) patients. Eight FD patients and eight healthy controls (HC) were involved in this study. Each HC received an 18F-FDG PET-CT scan at baseline, while each patient received scans at baseline and after acupuncture stimulations. Manual acupuncture stimulations were performed at ST34 (Liangqiu), ST36 (Zusanli), ST40 (Fenglong) and ST42 (Chongyang) in FD patients. The images were analyzed with the Statistical Parametric Mapping software 2.0. Compared to HC, the FD patients showed a lower glycometabolism in the right orbital gyrus, the left caudate tail and the cingulate gyrus, and a higher glycometabolism in the left inferior temporal gyrus (p<0.005). After acupuncture stimulations, the FD patients showed a glycometabolism decrease in the postcentral gyrus and the cerebella, and an increase in the visual-related cortices(p<0.005). The results suggest that the anterior cingulate cortex, the prefrontal cortices and the caudate tail involve in processing gastric perceptions in FD patients and that the deactivation of the primary somatosensory area and the cerebella is contributable to acupuncture stimulation, while activation of the visual-related cortex is a response to pain or acupoint actions.

Minimal acupuncture is not a valid placebo control in randomised controlled trials of acupuncture: a physiologist's perspective

Placebo-control of acupuncture is used to evaluate and distinguish between the specific effects and the non-specific ones. During 'true' acupuncture treatment in general, the needles are inserted into acupoints and stimulated until deqi is evoked. In contrast, during placebo acupuncture, the needles are inserted into non-acupoints and/or superficially (so-called minimal acupuncture). A sham acupuncture needle with a blunt tip may be used in placebo acupuncture. Both minimal acupuncture and the placebo acupuncture with the sham acupuncture needle touching the skin would evoke activity in cutaneous afferent nerves. This afferent nerve activity has pronounced effects on the functional connectivity in the brain resulting in a 'limbic touch response'. Clinical studies showed that both acupuncture and minimal acupuncture procedures induced significant alleviation of migraine and that both procedures were equally effective. In other conditions such as low back pain and knee osteoarthritis, acupuncture was found to be more potent than minimal acupuncture and conventional non-acupuncture treatment. It is probable that the responses to 'true' acupuncture and minimal acupuncture are dependent on the aetiology of the pain. Furthermore, patients and healthy individuals may have different responses. In this paper, we argue that minimal acupuncture is not valid as an inert placebo-control despite its conceptual brilliance.

Functional neuroanatomical investigation of vision-related acupuncture point specificity--a multisession fMRI study

The concept that specific acupuncture points have salubrious effects on distant target organ systems is a salient feature of Traditional Chinese Medicine (TCM). In this study, we used a multiple-session experiment to test whether electroacupuncture stimulation at two TCM vision-related acupoints, UB 60 and GB 37, located on the leg, could produce fMRI signal changes in the occipital regions of the brain, and the specificity of this effect when compared with stimulation at an adjacent non-acupoint (NAP). Six normal, acupuncture naive subjects completed the study. Each subject participated in six identical scanning sessions. Voxelwise group analysis showed that electroacupuncture stimulation at both vision-related acupoints and the NAP produced modest, comparable fMRI signal decreases in the occipital cortex, including the bilateral cuneus, calcarine fissure and surrounding areas, lingual gyrus, and lateral occipital gyrus. Further analysis of fMRI signal changes in occipital cortex showed no significant difference among the three points, UB 60, GB 37, and NAP. Our results thus do not support the view that acupuncture stimulation at vision-related acupoints induces specific fMRI blood oxygen level dependent (BOLD) signal changes in the occipital cortex. We speculate that cross modal inhibition, produced by needling-evoked somatosensory stimulation, may account for our finding of BOLD signal decreases in the occipital cortex. Given the complexity of acupuncture systems and brain activity, additional work is required to determine whether functional neuroanatomical correlates of acupoint specificity can be validated by means of brain imaging tools.

Expectancy and treatment interactions: a dissociation between acupuncture analgesia and expectancy evoked placebo analgesia

Recent advances in placebo research have demonstrated the mind's power to alter physiology. In this study, we combined an expectancy manipulation model with both verum and sham acupuncture treatments to address: 1) how and to what extent treatment and expectancy effects - including both subjective pain intensity levels (pain sensory ratings) and objective physiological activations (fMRI) - interact; and 2) if the underlying mechanism of expectancy remains the same whether placebo treatment is given alone or in conjunction with active treatment. The results indicate that although verum acupuncture+high expectation and sham acupuncture+high expectation induced subjective reports of analgesia of equal magnitude, fMRI analysis showed that verum acupuncture produced greater fMRI signal decrease in pain related brain regions during application of calibrated heat pain stimuli on the right arm. We believe our study provides brain imaging evidence for the existence of different mechanisms underlying acupuncture analgesia and expectancy evoked placebo analgesia. Our results also suggest that the brain network involved in expectancy may vary under different treatment situations (verum and sham acupuncture treatment).

FMRI connectivity analysis of acupuncture effects on an amygdala-associated brain network

Background

Recently, increasing evidence has indicated that the primary acupuncture effects are mediated by the central nervous system. However, specific brain networks underpinning these effects remain unclear.

Results

In the present study using fMRI, we employed a within-condition interregional covariance analysis method to investigate functional connectivity of brain networks involved in acupuncture. The fMRI experiment was performed before, during and after acupuncture manipulations on healthy volunteers at an acupuncture point, which was previously implicated in a neural pathway for pain modulation. We first identified significant fMRI signal changes during acupuncture stimulation in the left amygdala, which was subsequently selected as a functional reference for connectivity analyses. Our results have demonstrated that there is a brain network associated with the amygdala during a resting condition. This network encompasses the brain structures that are implicated in both pain sensation and pain modulation. We also found that such a pain-related network could be modulated by both verum acupuncture and sham acupuncture. Furthermore, compared with a sham acupuncture, the verum acupuncture induced a higher level of correlations among the amygdala-associated network.

Conclusion

Our findings indicate that acupuncture may change this amygdala-specific brain network into a functional state that underlies pain perception and pain modulation.

A combined [11C]diprenorphine PET study and fMRI study of acupuncture analgesia

Functional neuroimaging studies suggest that a lateral network in the brain is associated with the sensory aspects of pain perception while a medial network is associated with affective aspects. The highest concentration of opioid receptors is in the medial network. There is significant evidence that endogenous opioids are central to the experience of pain and analgesia. We applied an integrative multimodal imaging approach during acupuncture. We found functional magnetic resonance imaging signal changes in the orbitofrontal cortex, insula, and pons and [11C]diprenorphine positron emission tomography signal changes in the orbitofrontal cortex, medial prefrontal cortex, insula, thalamus, and anterior cingulate cortex. These findings include brain regions within both the lateral and medial pain networks.

Brain imaging of acupuncture: comparing superficial with deep needling

The difference between superficial and deep needling at acupuncture points has yet to be mapped with functional magnetic resonance imaging (fMRI). Using a 3T MRI, echo planar imaging data were acquired for 17 right-handed healthy volunteer participants. Two fMRI scans of acupuncture needling were taken in random order in a block design, one for superficial and one for deep needling on the right hand at the acupuncture point LI-4 (Hegu), with the participant blind to the order. For both scans needle stimulation was used. Brain image analysis tools were used to explore within-group and between-group differences in the blood oxygen level dependent (BOLD) responses. The study demonstrated marked similarities in BOLD signal responses between superficial and deep needling, with no significant differences in either activations (increases in BOLD signal) or deactivations (decreases in BOLD signal) above the voxel Z score of 2.3 with corrected cluster significance of P=0.05. For both types of needling, deactivations predominated over activations. These fMRI data suggest that acupuncture needle stimulation at two different depths of needling, superficial and deep, do not elicit significantly different BOLD responses. This data is consistent with the equivalent therapeutic outcomes that are claimed by proponents of Japanese and Chinese styles of acupuncture that utilise superficial and deep needling, respectively.

Neuroimaging acupuncture effects in the human brain

Acupuncture is an ancient East Asian healing modality that has been in use for more than 2000 years. Unfortunately, its mechanisms of action are not well understood, and controversy regarding its clinical efficacy remains. Importantly, acupuncture needling often evokes complex somatosensory sensations and may modulate the cognitive/affective perception of pain, suggesting that many effects are supported by the brain and extending central nervous system (CNS) networks. Modern neuroimaging techniques such as functional magnetic resonance imaging, positron emission tomography, electroencephalography, and magnetoencephalography provide a means to safely monitor brain activity in humans and may be used to help map the neurophysiological correlates of acupuncture. In this review, we will summarize data from acupuncture neuroimaging research and discuss how these findings contribute to current hypotheses of acupuncture action.

Point Injection as An Alternative Acupuncture Technique – An Exploratory Study of Responses in Healthy Subjects

Introduction

Point injection as a therapeutic technique is well documented, but its physiological effects have not been formally compared with traditional acupuncture. One aim of this study was to compare the effects of the two techniques at one acupuncture point, as a step towards understanding the mode of action of point injection and validating its clinical use. A second aim was to explore whether repeated point injection at the same site might provide a way of increasing the dose of stimulation, in the hope of identifying a dose response curve which could be an alternative strategy to placebo control in demonstrating the biological effects of acupuncture.

Methods

Sixty nine healthy subjects (age range 18–56 years, mean 29.9; 48 females) completed the study, which employed a counterbalanced experimental design with two stimulation sessions of LI4 approximately one week apart. One half of the participants received point injection first, and the other half received traditional acupuncture first. Baseline physiological data were recorded, then measurements were made before, during and after stimulation; each subject also reported needle sensation ( de qi). The measures were heart rate, derived pressure rate product and mean arterial pressure.

Results

Although stronger sensations of de qi were reported with point injection, no significant differences were found for mean heart rate (HR), pressure rate product (PRP) and mean arterial pressure (MAP) before and after stimulation by the two techniques. No subject gender or age bias was encountered and previous exposure to acupuncture had no effect on outcome. Power spectral analysis of heart rate variability (HRV) made on data from a small subset (n=10) of this cohort also showed no significant differences in autonomic response.

Conclusion

Point injection and traditional acupuncture seem to provoke similar physiological responses, although the greater needle sensation seen with point injection might indicate it could have more powerful clinical effects. Further studies of repeated point injection are necessary to indicate whether this technique may provide a method of increased strength of point stimulation, as an alternative to traditional needling in acupuncture research.

Holistic Acupuncture approach to idiopathic refractory nausea, abdominal pain and bloating

AIM: To evaluate the effectiveness of a holistic acupuncture approach on nausea, pain, bloating and electrogastrogram (EGG) parameters in patients with intractable symptoms.

METHODS: Twelve patients with no or mild nausea (those without nausea had bloating or pain) and 10 with a history of moderate to severe nausea were referred for acupuncture. All underwent an EGG and were treated at acupuncture points PC6, SP4 and DU20. Visual analog scales (VAS) assessing severity of nausea, pain and bloating were obtained before and after acupuncture treatment. Nineteen patients received three and three patients received two treatments.

RESULTS: VAS scores for nausea reflected the clinical assessment and differed significantly between mild and moderate/severe nausea groups. Acupuncture significantly improved severity of nausea in both groups with improved pre-treatment nausea between the first and third treatments in the moderate/severe nausea group. Pain scores improved with acupuncture in the mild nausea group only and bloating improved only with the first treatment in this group. Patients with bloating with VAS scores greater than 35 pre-treatment improved with acupuncture and over all VAS scores for pain improved with treatment. Acupuncture increased the power in the 2.7 to 3.5 cpm range in the EGG.

CONCLUSION: In this uncontrolled clinical study, a holistic acupuncture approach significantly improved nausea in patients with refractory symptoms and increased the power in the 2.7-3.5 cpm component of the electrogastrogram. Bloating and pain VAS scores improved acutely with treatment. This study suggests that acupuncture may be effective in this refractory group of patients and further study using appropriate controls is warranted.

fMRI review on brain responses to acupuncture: the limitations and possibilities in traditional Korean acupuncture

BACKGROUND

Since the late 1990s, imaging studies have allowed the visualization of brain response to acupuncture stimulation with alteration in blood flow. In 1998, the first functional magnetic resonance imaging (fMRI) study for the Korean acupuncture was published and thereafter, many subsequent neuroimaging studies with acupuncture have been published and revealed that acupuncture modulates central nervous system in human being. The purpose of this review is to summarize and evaluate the acupuncture studies using fMRI.

METHODS

A survey of computerized literature searches for experimental studies of acupuncture studies using fMRI revealed that a total of 19 studies were published from 1998 to 2005.

RESULTS

These studies have mainly focused on the correlation between acupoints and corresponding brain cortices, acupoint-specific patterns of brain activity. The analgesic effect of acupuncture implied that the pain network, including the hypothalamus and limbic system, was induced by different kinds of acupuncture stimulation. There are still several limitations in these experimental designs.

CONCLUSION

We reviewed studies that contributed to an understanding of the neurophysiologic mechanisms of acupuncture with the hope that this review will be of benefit to the future traditional Korean acupunctural fMRI studies.

Neural activities in human somatosensory cortical areas evoked by acupuncture stimulation

OBJECTIVES

To investigate neural representation evoked by acupuncture from human somatosensory cortices, especially from primary (SI) and secondary (SII) somatosensory areas.

DESIGN AND SETTING

Neuroimaging study - Blood-oxygenation-level-dependent (BOLD) functional MRI was performed during acupuncture on LI4 (n=12 healthy participants). Sham acupuncture and innocuous tactile stimulation were also applied on the same acupuncture site as control comparisons.

OUTCOME MEASURES

Responsive neural substrates were visualized and identified based on both individual and group-level surface activation maps.

RESULTS

Discrete regions within the precentral gyrus (area 4) and the fundus of the central sulcus (area 3a) were selectively activated during the real acupuncture stimulation. In SII, the activation was extended in a postero-inferior direction to the fundus of the lateral sulcus.

CONCLUSION

This specific pattern of acupuncture-related activation indicates that deep tissue stimulation (as seen in area 3a activation) and concurrent processing of sensory stimulation (as seen in activation in SII) may mediate neural responses to manual acupuncture.

Changes in FMRI in the human brain related to different durations of manual acupuncture needling

OBJECTIVES

The present study is aimed at evaluating the effects of manual acupuncture with different durations on the human brain using functional magnetic resonance imaging.

MATERIALS AND METHODS

Eighteen healthy right-handed volunteers were divided into three groups randomly. Each group received only one kind of acupuncture on the right LI4 (Hegu) point, which lasted 30 sec, 60 sec, or 180 sec, respectively. Fix-effect and conjunction analysis were used to compare the effects of the three kinds of acupunctures.

RESULTS

The results indicated that the stimulation of manual acupuncture with different durations could induce different effects in the central nervous system on the human brain. The longer duration of manual acupuncture might induce more significant areas.

CONCLUSIONS

The present study provided not only neuroimaging evidence for manual acupuncture, but also a useful guide for clinical applications of acupuncture. In addition, the results might be helpful to understand the relationship between the central nervous system responses and the durations of acupuncture.

Crossover clinical trial to determine the effect of manual acupuncture at Siguan points (bilateral LI4 and LR3) on intestinal motility in healthy subjects

This study examined whether manual acupuncture at the Siguan points (bilateral points LI4 and LR3) affects intestinal motility in healthy human subjects. Twenty healthy male subjects were randomly assigned either to real acupuncture (RA) at Siguan points or sham acupuncture (SA) groups in a crossover manner. All subjects underwent two experimental sessions; the RA group in the first session was treated with SA in the second session after a 2-week washout period, and vice versa. Each subject took 20 radio-markers and was treated with acupuncture 0, 12, 24, and 36 hours after radio-marker intake. Radiographs were taken at 6, 12.5, 24.5, and 48 hours, and the effect of acupuncture on intestinal motility was evaluated based on the distribution of the radio-markers in the ileum, ascending colon, transverse colon, descending colon, sigmoid/ rectum, and outside the body. Defecating habit was monitored during the trial, and complete blood counts were checked before and after the two acupuncture sessions. The RA and SA results showed extremely similar distributions of the radio-markers in these five regions of the alimentary canal and outside the body in radiographs taken at four different times, verifying that there was no effect of manual acupuncture at the Siguan points on intestinal motility, at least in healthy human subjects.

Test-retest study of fMRI signal change evoked by electroacupuncture stimulation

Recent efforts to use fMRI to investigate the effects of acupuncture needle manipulation on the brain have yielded discrepant results. This study was designed to test the reliability of fMRI signal changes evoked by acupuncture stimulation. Six subjects participated in six identical scanning sessions consisting of four functional scans, one for each of the four conditions: electroacupuncture stimulation (2 Hz) at GB 37, UB 60, non-acupoint (NP), and a control task of the finger tapping. In the group analysis across all subjects and sessions, both the average ratings on a Subjective Acupuncture Sensation Scale and the average fMRI signal changes (increases and decreases) were similar for GB37, UB 60, and NP. Visual inspection of the activation maps from individual sessions and ICC analysis revealed that fMRI signal changes evoked by electroacupuncture stimulation were significantly more variable than those from the control finger-tapping task. The relatively large variability across different sessions within the same subject suggests multiple sessions should be used to accurately capture the activation patterns evoked by acupuncture stimulation at a particular point for a specific subject.

Developing a research strategy for acupuncture

This strategic overview revisits some of the basic assumptions that relate to the clinical evaluation of acupuncture. We look at the evidence available to estimate both the specific and nonspecific effect size of acupuncture (efficacy and effectiveness) and consider the placebo within acupuncture trials, as well as the value of both placebo controlled trials and pragmatic acupuncture studies. We argue for an augmented, mixed methodology that integrates basic mechanism studies, including modern imaging techniques such as functional magnetic resonance, quantitative and qualitative research, as well as safety and health economic data to obtain a more rigorous understanding of acupuncture. We hope that by taking a broad, patient-centered, and rigorous approach we may arrive at a realistic and thoughtful evaluation of its relative value in comparison to placebo treatment, conventional medicine, and its potential for integration into conventional clinical care.

Acupuncture for nausea and vomiting: An update of clinical and experimental studies

The objective of this overview is to summarize existing knowledge about the effects of acupuncture-point stimulation on nausea and vomiting. Systematic reviews on postoperative nausea and vomiting, chemotherapy-induced nausea and vomiting, and pregnancy-related nausea and vomiting exist. Several randomised trials, but no reviews, exist for motion sickness. For postoperative nausea and vomiting, results from 26 trials showed acupuncture-point stimulation was effective for both nausea and vomiting. For chemotherapy-induced nausea and vomiting, results of 11 trials differed according to modality with acupressure appearing effective for first-day nausea, electroacupuncture appearing effective for first-day vomiting, and noninvasive electrostimulation appearing no more effective than placebo for any outcome. For pregnancy-related nausea and vomiting, results were mixed. Experimental studies showed effects of P6-stimulation on gastric myoelectrical activity, vagal modulation and cerebellar vestibular activities in functional magnetic resonance imaging. There is good clinical evidence from more than 40 randomised controlled trials that acupuncture has some effect in preventing or attenuating nausea and vomiting. A growing number of experimental studies suggest mechanisms of action.

Short- and long-term modulation of upper limb motor-evoked potentials induced by acupuncture

The aim of this study was to investigate in humans the effects of acupuncture upon upper-limb motor-evoked potentials (MEPs), elicited by transcranial magnetic stimulation of the primary motor cortex. It is known that peripheral sensory stimulation can be used to induce short- and long-term changes in motor cortex excitability. Data show that the simple insertion of the needle is an adequate somatosensory stimulus to induce a significant modulation of MEP amplitude, the sign of which (facilitation or inhibition) is specific to the investigated muscle and to the point of needle insertion. Moreover, MEP changes in upper-limb muscles are also observed following needling of lower-limb sites, revealing the presence of long-distance effects of acupuncture. Finally, the modulation in muscle excitability considerably outlasts the time period of needle application, demonstrating the induction of long-term plastic changes in the central nervous system. In addition, results have shown that the effects on muscle excitability are not restricted to the stimulation of well-coded acupoints, as described in traditional Chinese medicine, but they can also be induced by needling of nonacupoints, normally not used for therapeutic purposes. The possible neuronal mechanisms underlying the observed effects of acupuncture are discussed in relation to the available neurophysiological data regarding the interlimb reflexes and the changes in the representational cortical maps induced in humans by a prolonged somatosensory stimulation.

Acupuncture for functional gastrointestinal disorders

Functional gastrointestinal (GI) symptoms are common in the general population. Especially, motor dysfunction of the GI tract and visceral hypersensitivity are important. Acupuncture has been used to treat GI symptoms in China for thousands of years. It is conceivable that acupuncture may be effective in patients with functional GI disorders because it has been shown to alter acid secretion, GI motility, and visceral pain. Acupuncture at the lower limbs (ST-36) causes muscle contractions via the somatoparasympathetic pathway, while at the upper abdomen (CV-12) it causes muscle relaxation via the somatosympathetic pathway. In some patients with gastroesophageal reflux disease (GERD) and functional dyspepsia (FD), peristalsis and gastric motility are impaired. The stimulatory effects of acupuncture at ST-36 on GI motility may be beneficial to patients with GERD or FD, as well as to those with constipation-predominant irritable bowel syndrome (IBS), who show delayed colonic transit. In contrast, the inhibitory effects of acupuncture at CV-12 on GI motility may be beneficial to patients with diarrhea-predominant IBS, because enhanced colonic motility and accelerated colonic transit are reported in such patients. Acupuncture at CV-12 may inhibit gastric acid secretion via the somatosympathetic pathway. Thus, acupuncture may be beneficial to GERD patients. The antiemetic effects of acupuncture at PC-6 (wrist) may be beneficial to patients with FD, whereas the antinociceptive effects of acupuncture at PC-6 and ST-36 may be beneficial to patients with visceral hypersensitivity. In the future, it is expected that acupuncture will be used in the treatment of patients with functional GI disorders.

The integrated response of the human cerebro-cerebellar and limbic systems to acupuncture stimulation at ST 36 as evidenced by fMRI

Clinical and experimental data indicate that most acupuncture clinical results are mediated by the central nervous system, but the specific effects of acupuncture on the human brain remain unclear. Even less is known about its effects on the cerebellum. This fMRI study demonstrated that manual acupuncture at ST 36 (Stomach 36, Zusanli), a main acupoint on the leg, modulated neural activity at multiple levels of the cerebro-cerebellar and limbic systems. The pattern of hemodynamic response depended on the psychophysical response to needle manipulation. Acupuncture stimulation typically elicited a composite of sensations termed deqi that is related to clinical efficacy according to traditional Chinese medicine. The limbic and paralimbic structures of cortical and subcortical regions in the telencephalon, diencephalon, brainstem and cerebellum demonstrated a concerted attenuation of signal intensity when the subjects experienced deqi. When deqi was mixed with sharp pain, the hemodynamic response was mixed, showing a predominance of signal increases instead. Tactile stimulation as control also elicited a predominance of signal increase in a subset of these regions. The study provides preliminary evidence for an integrated response of the human cerebro-cerebellar and limbic systems to acupuncture stimulation at ST 36 that correlates with the psychophysical response.

Investigating acupuncture using brain imaging techniques: the current state of play

We have systematically researched and reviewed the literature looking at the effect of acupuncture on brain activation as measured by functional magnetic resonance imaging and positron emission tomography. These studies show that specific and largely predictable areas of brain activation and deactivation occur when considering the traditional Chinese functions attributable to certain specific acupuncture points. For example, points associated with hearing and vision stimulates the visual and auditory cerebral areas respectively. Pain, however, is a complex matrix that is intimately intertwined with expectation. Acupuncture clearly affects this matrix in both specific and non-specific manner that is consistent with its specific clinical effects, as well as the effects of expectation on pain relief. This article summarizes the current imaging literature.

Acupoint-specific fMRI patterns in human brain

Specific central nervous system (CNS) responses to acupuncture have recently attracted attention. It is important to understand the differences in fMRI images of the brain evoked by acupuncture at an acupoint and at a nearby "sham" point. Here, we report analyses of fMRI images of the brains of 37 healthy volunteers in response to acupuncture at Liv3 (Taichong) and LI4 (Hegu) versus their sham points. We found common activation areas in response to Liv3 or LI4 acupuncture in the middle temporal gyrus and cerebellum, along with deactivation areas in the middle frontal gyrus and inferior parietal lobule, compared with the effects of acupuncture at sham points. Acupuncture at Liv3 evoked specific activation at the postcentral gyrus, posterior cingulate, parahippocampal gyrus, BA 7, 19 and 41, but deactivation at the inferior frontal gyrus, anterior cingulate, BA 17 and 18, compared with acupuncture at its sham point. Acupuncture at LI4 evoked specific activation at the temporal pole, but deactivation at the precentral gyrus, superior temporal gyrus, pulvinar and BA 8, 9 and 45, compared with acupuncture at its sham point. These observations reveal that acupuncture at acupoints induces specific patterns of brain activity, and these patterns may relate to the therapeutic effects of acupuncture.