The Salient Characteristics of the Central Effects of Acupuncture Needling: Limbic-Paralimbic- Neocortical Network Modulation

Transcription

1 Human Bain Mapping 30: (2009) The Salient Chaacteistics of the Cental Effects of Acupunctue Needling: Limbic-Paalimbic- Neocotical Netwok Modulation Jiliang Fang, 1,2 * Zhen Jin, 3 Yin Wang, 4 Ke Li, 3 Jian Kong, 2 Eika E. Nixon, 2 Yawei Zeng, 3 Yanshuang Ren, 1 Haibin Tong, 1 Yinghui Wang, 4 Ping Wang, 1 and Kathleen Kin-Sang Hui 2 1 Depatment of Radiology, Guang An Men Hospital, China Academy of Chinese Medical Sciences, Beijing, China 2 Depatment of Radiology, Athinoula A. Matinos Cente fo Biomedical Imaging, Massachusetts Geneal Hospital and Havad Medical School, Chalestown, Massachusetts 3 MRI Division, Depatment of Radiology, Beijing 306 Hospital, Beijing, China 4 Depatment of Acupunctue, Guang An Men Hospital, China Academy of Chinese Medical Sciences, Beijing, China Abstact: Human and animal studies suggest that acupunctue poduces many beneficial effects though the cental nevous system. Howeve, the neual substates of acupunctue actions ae not completely clea to date. fmri studies at Hegu (LI4) and Zusanli (ST36) indicated that the limbic system may play an impotant ole fo acupunctue effects. To test if this finding applies to othe majo classical acupoints, fmri was pefomed on 10 healthy adults duing manual acupunctue at Taichong (LV3), Xingjian (LV2), Neiting (ST44), and a sham point on the dosum of the left foot. Although cetain diffeences could be obseved between eal and sham points, the hemodynamic esponse (BOLD signal changes) and psychophysical esponse (sensoy expeience) to acupunctue wee geneally simila fo all fou points. Acupunctue poduced extensive deactivation of the limbic-paalimbic-neocotical system. Clustes of deactivated egions wee seen in the medial pefontal cotex (fontal pole, pegenual cingulate), the tempoal lobe (amygdala, hippocampus, and paahippocampus) and the posteio medial cotex (pecuneus, posteio cingulate). The sensoimoto cotices (somatosensoy cotices, supplementay moto cotex), thalamus and occasional paalimbic stuctues such as the insula and anteio middle cingulate cotex showed activation. Ou esults povide additional evidence in suppot of pevious epots that acupunctue modulates the limbic-paalimbic-neocotical netwok. We hypothesize that acupunctue may mediate its antipain, antianxiety, and othe theapeutic effects via this intinsic neual cicuit that plays a cental ole in the affective and cognitive dimensions of pain as well as in the egulation and integation of emotion, memoy pocessing, autonomic, endocine, immunological, and sensoimoto functions. Hum Bain Mapp 30: , VC 2008 Wiley-Liss, Inc. Key wods: acupunctue; fmri; limbic-paalimbic-neocotical netwok; acupoint specificity; needling; deqi This study was pesented in pat at the Society fo Neuoscience Annual Confeence, Oct 2006, Atlanta, GA, USA. Contact gant sponso: State Administation of Taditional Chinese Medicine, China; Contact gant numbe: CNTCM2003LHR5; Contact gant sponsos: National Cente fo Complementay and Altenative Medicine, National Institutes of Health (NCCAM NIH); Contact gant numbe: 5F05 AT , 02. *Coespondence to: Jiliang Fang, 5 Bei Xian Ge Steet, Xuan Wu Qu, Beijing , China. fang@nm.mgh.havad.edu Received fo publication 8 Septembe 2007; Revised 20 Febuay 2008; Accepted 11 Mach 2008 DOI: /hbm Published online 20 June 2008 in Wiley InteScience (www. intescience.wiley.com). VC 2008 Wiley-Liss, Inc.

2 Acupunctue Modulates the Limbic System INTRODUCTION Acupunctue is becoming one of the most widely used teatments in altenative medicine [NIH, 1998]. Clinical and expeimental studies indicate that most of the antipain, antianxiety, and othe modulatoy effects of acupunctue ae mediated via the cental nevous system [Han, et al., 1982; Pomeanz, 1995; Zhu, 1997]. Howeve, the pathways of acupunctue actions on the bain have not been well chaacteized to date. Recently, fmri has been used successfully to monito the dynamic esponse of the bain to acupunctue in human subjects [Cho et al., 1998, 2000, 2006b; Fang et al., 2004, 2006, 2007; Gaeus et al., 2002; Hui et al., 1997a,b, 1998, 2000, 2005; Kong et al., 2002, 2007a,b; Li et al., 2003a,b; Liu et al., 2004; Napadow et al., 2005, 2007; Paish et al., 2005; Sun et al., 2006; Wang et al., 2007; Wu et al., 1999, 2002; Yan et al., 2005; Yoo et al., 2004; Zhang et al., 2003, 2004]. These studies show that acupunctue stimulation poduces extensive hemodynamic esponse within the subcotical and cotical egions. Many acupunctue fmri studies have focused on acupoints that ae most widely used in clinical pactice, such as LI4, ST36, and GB34. The oveall esponse patten showed significant ovelap between them in eithe manual o electical acupunctue. Besides activation of the somatosensoy and association cotices that is to be expected of somatosensoy stimulation, widespead deactivation occus in the limbic system [Fang et al., 2006; Hui et al., 2000, 2005; Kong et al., 2002; Napadow et al., 2005; Wang et al., 2007; Wu et al., 1999, 2002]. A majo subset of these bain aeas is closely associated with the pain matix, such as: the cingulate cotex, amygdala, hippocampus, thalamus, insula, and peiaqueductal gay. Othe acupoints have also been investigated, including BL57, BL60, BL67, K3, LV3, GB40, SP6, SJ8, DU15, PC6, GB37 [Cho et al., 1998, 2000; Fang et al., 2004, 2007; Kong et al., 2007a,b; Li et al., 2003a,b; Paish et al., 2005; Yan et al., 2005; Yoo et al., 2004; Zhang et al., 2004]. Many of the authos intepet the diffeences between acupoints o the diffeences between acupoints and sham points as acupoint specificity in suppot of the taditional Chinese medicine (TCM) theoy. Howeve, the evidence is as yet unconvincing. Consideable discepancy exists in the liteatue. Cho et al. wee the fist to epot that highly specific effects wee associated with diffeent acupoints, that acupunctue at vision-elated Kunlun (BL60), Zhiyin (BL67) activated the visual cotex while acupunctue at auditoy-elated Taixi (K3) activated the auditoy cotex [Cho et al., 1998, 2000; Li et al., 2003a; Paish et al., 2005]. Howeve, the esults could not be eplicated [Gaeus et al., 2002]. It has been shown by multiple studies that acupunctue at many nonvision o nonauditoy elated acupoints also elicited BOLD signal esponse in the visual o auditoy cotex [Fang et al., 2006, 2007; Hui et al., 2005; Kong et al., 2007a,b; Li et al., 2003b; Napadow et al., 2005, 2007; Sun et al., 2006; Wang et al., 2007; Wu et al., 2002; Yan et al., 2005; Yoo et al., 2004]. Cho has ecently eplaced his acupoint-bain-ogan" specific pathway theoy with the boad sense hypothalamus-pituitay-adenal axis" hypothesis [Cho et al., 2006a,b]. On the othe hand, Hui hypothesizes that acupunctue ecuits intinsic bain netwoks involved in the egulation and integation of multiple bain functions to mediate its effects, and that the limbic system may play a majo ole. Functional MRI studies of acupunctue at Hegu (LI4), Zusanli (ST36) and Taichong (LV3) have povided evidence in suppot of the hypothesis [Fang et al., 2007; Hui et al., 1997b, 1998, 2000, 2005; Sun et al., 2006]. The pesent study compaes the fmri esponse of the bain to acupunctue at multiple acupoints of diffeent meidian oigins on the same individuals in ode to exploe the effects that may be specific o common to the diffeent acupoints. Acupunctue was pefomed at Taichong (LV3) and Xingjian (LV2) of the live meidian, Neiting (ST44) of the stomach meidian and a sham point located between the III and IV metatasals on the foot. These acupoints of meidian oigin ae commonly used fo teating pain, hypetension, gastointestinal, and othe physiological dysfunctions [Chen, 1995; Cheng, 2000]. The esults of the study povided additional evidence fo the modulation of the limbic system by acupunctue. MATERIALS AND METHODS Subject Recuitment and Evaluation Thity healthy adult voluntees wee ecuited by advetisements appoved by the Institutional Review Boad at Guang An Men Hospital, China Academy of Chinese Medical Sciences. A qualified staff membe in the study goup explained the pupose of the investigation, its pocedue, its potential discomfots and isks, and obtained a signed infomed consent fom the candidate pio to commencement of the study pocedues. The subjects wee enolled and petested fo esponse to acupunctue analgesia with themal stimulation on the fist toe. Subjects whose pain theshold was elevated 10% o moe by acupunctue wee enolled into the imaging test. The successful candidates included 5 male and 5 female, 22 to 28 yeas old, ight handed and no histoy of mental and psychological disodes. All of them had expeience of acupunctue befoe ou study and had a positive view about acupunctue. Acupunctue Potocol Manual acupunctue was administeed by the same licensed acupunctuist thoughout the study. Thee classical acupoints (LV3, LV2, and ST44) and a sham point between metatasal III and IV on the dosum of the left foot wee tested in andomized ode, using disposable steile stainless steel needles, diamete 0.25 mm, length 30 mm (Huatuo, Suzhou Medical Appliance Company). Each expeimental un lasted 6 min [Fig. 1]. The needle was inseted pependicula to the skin suface to a depth of 1197

3 Fang et al. Figue 1. Acupunctue: LV2, LV3 of live meidian, ST44 of stomach meidian, sham point between metatasals III and IV. Needle inseted and petested fo sensations pio to scanning. Total scan time 6 min. Thee stimulation peiods (S1,2,3) wee inteleaved with est peiods (R1) without needle and (R2, 3) with needle in place, each lasting 1 min. 2 4 mm depending on the acupoint. It was otated backwad and fowad with even motion at a ate of 160/min with an amplitude aound Epochs of needle manipulation wee inteleaved with epochs of needle at est, each lasting 1 min. The diffeent deqi sensations expeienced by the subject duing needle manipulation including aching, soeness, numbness, and distension wee scoed by the subject on a scale of 0 5 afte evey pocedue. It was the acupunctuist s aim to geneate deqi o acupunctue sensations without povoking undue discomfot o shap pain [Hui et al., 2000, 2005]. Imaging All MRI expeiments wee pefomed at a 1.9 T whole body scanne (Pestige, GE/Elscint, Haifa, Isael) equipped with a volumetic head coil. Fo the fmri images, a gadient echo plana imaging (EPI) T2*-weighted sequencebased on blood oxygenation level dependent (BOLD) effect was employed [Kwong et al., 1992], using TR/TE at 3,000 ms/45 ms, flip angle 908, field of view (FOV) mm 2, matix , in-plane esolution mm 2. Nineteen continuous axial sections, each 6.0 mm thick, wee collected to encompass the whole bain. Anothe set of 19 contiguous axial spin-echo T1-weighted images (TR/ TE 750/12 ms, FOV mm 2, 6.0 mm thick esolution 1 3 1mm 2 ) was acquied fo image egistation. fmri Data Analysis Individual and goup analysis of functional imaging data wee pefomed using SPM99. The data acquied in the fist minute wee excluded fom the analysis to discad the unstable BOLD signals. Functional images wee ealigned fo head motion (none of the subjects had head movements exceeding 2 mm). All functional images wee nomalized to MNI (Monteal Neuological Institute) steeotactic space and spatially smoothed by an 8 mm fullwidth half-maximum Gaussian kenel. The fixed effects analysis was used fo the individual data of each acupoint o the sham point fom evey subject, based on the geneal linea model with box ca function as the efeence wavefom convolved with Poisson HRF (Haemodynamic Response Function). Regional activation and deactivation of bain egions duing acupunctue was thesholded at P (uncoected) with a minimum cluste size of 10 contiguous voxels. The analysis of andom effects (one-sample t test on a voxel-by-voxel basis) was pefomed fo goup data of each acupoint o the sham point fom 10 subjects, thesholded at the same P value and cluste size as the individual analysis. Futhemoe, one-way ANOVA (analysis of vaiance) was used to exploe the diffeences among the classical points and sham point (P 0.005, uncoected, minimal cluste size 10 voxels, the degees of feedom 9). Thei time-couses wee checked to ensue coelation with the expeimental paadigm. The locations of the egions of inteest ae pesented in MNI coodinates. Acupunctue Sensations Analysis The sum of the scoes fo the sensations epoted by the subject povided a total acupunctue sensations scoe. The deqi esponse was thesholded at a minimal total scoe of 5. The Fishe s exact test and the student s t test wee used to compae the fequency and intensity of sensations between points espectively. RESULTS Psychophysical Response Most of the subjects epoted deqi duing acupunctue at all fou points, 8 of 9 subjects fo LV2, 8 of 10 fo the sham point, 7 of 10 fo ST44 and 6 of 9 fo LV3 espectively (P > 0.05). One subject with acupunctue at LV3 and LV2 did not have sensations ecoded. Aching was significantly moe intense at LV3 compaed with LV2 (P < 0.05). 1198

4 Acupunctue Modulates the Limbic System Figue 2. Activation netwok: bilateal insula, thalamus, anteio middle cingulate cotex (amcc), somatosensoy cotex (SII: BA40, 43). (n 5 10), P 0.001, minimal cluste size of 10 voxels, uncoected. No significant diffeence was obseved in the intensity and fequency of othe sensations between the points. No subjects expeienced shap pain. Hemodynamic Response Oveall, the goup data of the hemodynamic esponse to acupunctue at the thee acupoints and the sham point shaed many common featues in the pattens of bain activation o deactivation, even though thee wee diffeences in pefeential locations and in the magnitude of signal change between the points [Figs. 2 and 3, Tables I and II]. Activation Netwok [Fig. 2, Table I] The spatial distibution and the intensity of the signal inceases showed significant similaity acoss the points. The seconday somatosensoy cotex (SII_BA40/43), supplementay moto cotex (SMC_BA6), insula, thalamus, and anteio middle cingulate cotex (amcc_ba24/32) showed stong bilateal activation fo all the points. Signal inceases in the thalamus and SMC_BA6 wee moe pominent on the ight (contalateial) hemisphee. Vaiation between acupoints was obseved in the pimay somatosensoy cotex (BA3/1/2), supeio tempoal gyus (BA22), supeio fontal gyus (BA46) and posteio cingulate cotex (BA23_dosal). Deactivation in the Limbic-Paalimbic-Neocotical Netwok [Fig. 3, Table II] The decease in signal intensity was concentated in thee bain egions: the medial pefontal cotex (fontal pole, pegenual cingulate), the tempoal lobe (amygdala, hippocampus, paahippocampus, and tempoal pole) and the posteio medial cotex (PMC) (pecuneus, posteio cingulate). Most of the stuctues eithe belonged to o wee intimately elated to the limbic system. The esponse was geneally bilateal. The fontal pole (BA10_medial) was deactivated fo all the points. Howeve, deactivation of the pegenual cingulate (BA32) was seen only with LV2 and the sham point. Inteestingly, the esponse at the sham point was simila to LV3, but moe intensive and extensive than LV2 and ST44. In the tempoal lobe, signal deceases wee detected in the hippocampus and paahip- 1199

5 Figue 3. Deactivation netwok: fontal pole (BA10_medial), pegenual cingulate cotex (BA32), hippocampus, paahippocampus, posteio cingulate cotex (BA23,31), pecuneus (BA7_ medial). (n 5 10), P 0.001, minimal cluste size of 10 voxels, uncoected. TABLE I. Regions of fmri signal Incease duing acupunctue (n 510) LV3 LV2 ST40 Sham Stuctue Hemis-phee a Peak T-value Peak T-value Peak T-value Peak T-value amcc(ba24/32) L 23,7, ,23, ,30, ,27, R 3,9, ,6, ,24, ,33, SMC(BA6) L 23,21, ,12, ,12, ,6, R 3,12, ,12, ,12, ,6, Thalamus L 29,212, ,214, ,215, ,212, (Dosomedial) R 12,215, ,214, ,214, ,212, Insula L 242,18, ,15, ,24, ,18, R 36,12, ,21, ,24, ,21,29 5 SII(BA43) L 259,214, ,214, ,212, ,29, R 60,215, ,212, ,212, ,29, SII(BA40) L 263,224, ,218, ,218, ,218, R 53,225, ,227, ,224, ,224, SI(BA3,1,2) L 254,218, ,221, BA, Bodmann aea; amcc, anteio middle cingulate cotex; SMC, supplementay moto cotex; SII, seconday somatosensoy cotex; SI, pimay somatosensoy cotex. P T 3.11 uncoected. The activations of somatosensoy cotices, thalamus and Insula duing acupunctue wee simila in the geneal patten fo the fou points, Activation of SI was not obseved with ST40 and the Sham point. The MNI coodinates and the peak T value wee taken fom the voxel with maximal signal change fo each stuctue. a Left: Ipsilateal.

6 Acupunctue Modulates the Limbic System TABLE II. Regions of fmri signal decease duing acupunctue (n 5 10) LV3 LV2 ST40 Sham Stuctue Hemisphee a Peak T value Peak T value Peak T value Peak T value FP(BA10) L 23,60,0 25,03 26,54, ,54, ,45, R 6,57, ,51, ,54, ,57, pegenual CC(BA32) L 26,36, ,39, R 9,36, ,36, Amygdala L 224,29, ,26, ,23, R Hippocampus L 227,236, ,233, ,221, ,212, R 30,239, ,239, ,233, Paahyppocampus L 224,242, ,245, ,236, R 30,245, ,245, ,236, TP(BA38) L 245,12, ,12, R 48,6, ,9, ,9, PCN(BA7) L 23,245, ,260, ,236, R 6,239, ,236, PCC(BA31) L 29,260, ,258, ,57, ,233, R 6,254, ,248, ,242, ,254, RCS(BA29/30) L 26,251, ,250, ,248, R 12,251, ,245, ,248, CN(BA18/19) L 29,284, ,284, ,275, R 6,278, ,278, ,284, ,272, BA Bodmann aea; FP, fontal pole; Pegenual CC, anteio cingulate cotex; TP, tempoal pole; PCN, Pecuneus; PCC, posteio cingulate cotex; RCS, etosplenial cotex; CN, cuneus. P T 3.11 uncoected. The deactivations in the limbic-paalimbic-neuocotical system fo fou points wee simila in the geneal patten. The MNI coodinates and the peak T values wee taken fom the voxel with maximal signal change fo each stuctue. a Left: ipsilateal. pocampus fo LV2, LV3, and the sham point. In contast, no signal changes wee found in paahippocampus and ight hippocampus fo ST44. The ight amygdala was deactivated with LV2, ST44, and the sham point but not with LV3. The tempoal pole showed signal decease with LV3, ST44, and the sham point. The PMC demonstated widespead bilateal deactivation in the pecuneus (BA7_medial), posteio cingulate (BA31, BA23_vental) and etosplenial cotex (BA29/30) fo most of the points, with the exception of BA29/30 fo ST44, and BA7_medial fo LV2. The extastiate visual cotex (BA18/19) showed deactivation fo all points. The esults of ANOVA showed that diffeences in fmri signal esponse between the eal acupoints (LV2, ST44) and the sham point wee limited to a small numbe of spatial distibutions with small changes in signal intensity (thesholded at P 0.005) [Table III]. The left tempoal pole was activated fo LV2 but deactivated fo the sham point. The posteio cingulate cotex (BA31) evealed deactivation with the sham point but not with LV2 and ST44. The ight supa- TABLE III. fmri Signal changes acupoint vs sham point (one-way ANOVA) Stuctue Hemisphee Peak T-value T (LV2) T (sham) T (ST44) LV2 vs Sham TP(BA38) L 239,6, PCC(BA31) L 29,30, PCC(BA31) R 9,236, SMG(BA40) R 51,233, ST44 vs Sham PCC(BA31) L 29,230, RSC(BA30) L 29,233, LV3 vs Sham No voxel above the theshold BA, Boadmann aea; TP, tempoal pole; PCC, posteio cingulate cotex; RSC, etosplenial cotex; SMG, supamaginal gyus. P 0.005/T Diffeences in BOLD fmri signal esponse wee detected: In the TP, PCC, SMG between LV2 and sham; and In the PCC, RSC between ST44 and sham point. No significant diffeence was noted between LV3 and the sham point. The MNI co-odinates and the peak T value wee taken fom the voxel with maximal signal change fo each stuctue. 1201

7 Fang et al. maginal gyus (BA40) showed activation fo LV2, and the left etosplenial cotex (BA30) deactivation fo ST44; these changes wee not obseved fo the sham point. No diffeence was detected between LV3 and the sham point. DISCUSSION In ou study we compaed the cental effects of manual acupunctue at thee classical acupoints on two meidians and a non-meidian point in the vicinity. All fou sites ae located in muscle/connective tissue layes supplied with simila segmental innevations (peoneal neve, L4-S1). The oveall hemodynamic esponse demonstated many common featues in the activation and deactivation netwoks, though vaiations in pefeential spatial distibutions and magnitude of esponse wee obseved. Deactivation in the Limbic-Paalimbic- Neocotical Netwok Pominent fmri signal deceases wee distibuted in the fontal pole, medial pefontal cotex, anteio cingulate cotex; amygdala, hippocampus, paahippocampus, tempoal pole; pecuneus, posteio cingulate, and etosplenial cotex to fom a geneal patten of LPNN deactivation fo all the points. The esults wee consistent with pevious epots of fmri signal esponse of acupunctue at diffeent acupoints. Manual acupunctue at LI4, ST36, and LV3 showed signal deceases in diffeent limbic, paalimbic and neocotical egions such as the amygdala, hippocampus, paahippocampus, anteio cingulate cotex, pecuneus, medial pefontal cotex, and tempoal pole [Fang et al., 2006, 2007; Hui et al., 1997b, 2000, 2005; Hui, 2007; Kong et al., 2002; Napadow et al., 2005; Sun et al., 2006; Wu et al.,1999; Yan et al., 2005]. Electoacupunctue at LI4, ST36, SP6, GB34, GB37, and UB60 demonstated simila signal deceases in the amygdala, hippocampus, paahippocampus, anteio cingulated cotex, medial obital pefontal cotex, hypothalamus, and pecuneus [Kong et al., 2002, 2007a; Napadow et al., 2005; Wang et al., 2007; Wu et al., 2002]. Tanscutaneous electical neve stimulation at ST36 and SP6, o GB34 and BL57 also evealed deactivation in hippocampus and amygdale. Moeove, deactivation of the amygdala and hippocampus was found to coelate with the elevation of pain theshold in the subjects [Zhang et al., 2003]. Thus, the in vivo evidence of acupunctue action on humans as evealed by moden neuoimaging stongly suggests that the deactivation of the LPNN is chaacteistic of acupunctue needling. Howeve, consideable contovesy is found in the acupunctue neuoimaging liteatue [Dhond et al., 2007]. Like most fmri/pet studies in othe fields most investigatos have focused on the activation effects of acupunctue stimulation. Until ecently, epots of activation fa outnumbe those of deactivation. Signal inceases have been epoted in the visual cotex, auditoy cotex, pimay, and seconday somatosensoy cotices, supplementay moto cotex, cingulate cotex, thalamus, insula, hypothalamus, peiaqueductal gay, and ceebellum [Biella et al., 2001; Cho et al., 1998, 2000; Fang et al., 2004; Hsieh et al., 1998; Li et al., 2003a,b; Liu et al., 2004; Paish et al., 2005; Yan et al., 2005; Yoo et al., 2004]. While the finding of activation in most of these egions is valid, the intepetation that the esponse was specific to the acupoints employed is unconvincing. Contay to the high specificity epoted fo the visual and auditoy acupoints as mentioned above, acupunctue at many nonvision o nonauditoy elated acupoints also elicited BOLD signal esponse in the visual o auditoy cotices. While the diffeent esults in the liteatue may be attibuted to the acupoints employed, it is likely that the intensity of stimulation, needling techniques, data acquisition, and the confounding effect of shap pain may be impotant factos. We have shown in epeated studies that the hemodynamic esponse was makedly influenced by the sensoy expeience. With gentle needling that induced deqi absent shap pain, extensive deactivation was obseved in the limbic-paalimbic-neocotical netwok as descibed ealie. In the concomitant pesence of inadvetent shap pain, the signal deceases in a lage subset of these egions wee attenuated o eveted to signal inceases [Fang et al., 2007; Hui et al., 2000, 2005, 2007; Napadow et al., 2005; Sun et al., 2006]. Inadvetent noxious stimulation could occu when the intensity of stimulation exceeds the subject s pain theshold. The pain that esults will obscue the effect of deqi on the LPNN, the salient featue of acupunctue needling. It is, theefoe, highly ecommended to sepaate the datasets accoding to the psychophysical esponse in the data analysis, a pactice that is as yet uncommon in the acupunctue imaging liteatue. The Neuoanatomical and Functional Connectivities in the Limbic-Paalimbic-Neocotical Netwok The limbic-paalimbic-neocotical cicuit plays a majo ole in modulating the cognitive and affective dimensions of pain pocessing, and is cental to the egulation and integation of emotion, cognition, conciousness, sensoimoto, autonomic, endocine, and immunological functions. Extensive and dense inteconnections in the limbic-paalimbic-neocotical system ae demonstated by neual tace s technique in monkeys. Fo example, all PMC aeas ae inteconnected with the anteio cingulate, the medial pefontal cotex, amygdale, and hippocampus; while the obital and medial pefontal cotex (OMPFC) ae extensively linked with the medial tempoal lobe and cingulate limbic stuctues [Camichael and Pice, 1995; Pavizi et al., 2006; Vogt et al., 2006]. Such intimate anatomical connections suppot a close functional elationship among limbic-paalimbic-neocotical stuctues. It is widely ecognized that the amygdala, hippocampus, paahipocampus, and anteio cingulate cotex play a cental ole in the egulation of 1202

8 Acupunctue Modulates the Limbic System emotions, motivation, memoy, and affective dimension of pain [LeDoux, 2000; Rainville et al., 1997; Zubieta et al., 2001]. The PMC is citical in a wide spectum of highly integated tasks such as visuo-spatial imagey, episodic memoy etieval and self-pocessing opeations [Cavanna and Timble, 2006; Vincent et al., 2006]; the OMPFC may be involved in sensoy integation, decision making and expectation [Gusnad et al., 2001; Mill and Wallis, 2002]. The lage subset of the deactivation egions involved such as the medial pefontal cotex, anteio cingulate cotex, amygdala, hippocampus, paahippocampus, and PMC is known to be activated by pain, anxiety, and psychostimulants [Becea et al., 1999; Bingel et al., 2002; Kufahl et al., 2007; Simpson et al., 2001]. This phenomenon was also obseved in acupunctue that povoked shap pain [Fang et al., 2007; Hui et al., 2000, 2005; Sun et al., 2006]. Moeove, it was epoted that the deactivation of the amygdala and hippocampus coelated with the elevation of pain theshold in the subjects [Zhang et al., 2003]. The intepetation of deceases in BOLD signals is not completely clea, but inceasing evidence indicates that it is a make of neuonal deactivation [Shmuel et al., 2006; Stefanovic et al., 2004]. Acupunctue may mediate its antipain, antianxiety, and othe divese modulatoy effects via deactivation of this limbic-paalimbic-neocotical cicuit. Defaut Mode Netwok and the Limbic-Paalimbic-Neocotical Netwok Inteestingly, the so-called default mode netwok (DMN) of the bain ovelaps with the LPNN deactivated by acupunctue [Fang et al., 2007; Hui et al., 2000, 2005, 2007]. These egions demonstate highest metabolic ate when a subject is at est, but become deactivated duing goal-diected tasks [Buckne et al., 2008; Fansson, 2006; Raichle et al., 2001; Shulman et al., 1997]. It is suggested that the impotant function of this netwok is to ente a mode of pepaedness and aletness fo possible changes in the intenal o extenal milieu. We postulate that this intinsic oganization may paticipate as a coe of the LPNN netwok that esponse to acupunctue stimulation. Activation Netwok in Acupunctue Studies The activation in somatosensoy cotex togethe with its associated cotices and thalamus is to be expected fom somatosensoy stimulation at somatic points [Davis et al., 1998]. Howeve, a couple of paalimbic egions ae also involved. The anteio middle cingulate cotex is elated to cognitive attention, opioidegic pain modulation as well as placebo analgesia [Benedetti et al., 1999; Han et al., 1982; Schnitzle and Plone, 2000; Zubieta et al., 2001]. The insula pocesses convegent infomation to poduce an emotionally elevant context fo sensoy expeience, including olfactoy, gustatoy, and viscea s stimulations [Caia et al., 2007; Davis et al., 1998]. Oveall, this study showed moe pominent activation in intensity and in extent compaed to some ealie studies in manual acupunctue [Fang et al., 2004, 2006, 2007; Hui et al., 2000, 2005; Wu et al., 1999]. This could contibute to the stonge stimulation of the somatosensoy netwok: the speed of needle manipulation of 160/min was faste than othe fmri studies (60 120/min) in the liteatue. fmri BOLD Signal Change Pattens: Acupoints vesus Sham Point The main pupose of compaing a meidian point (acupoint) and a nonmeidian point (sham point) is to examine if the cental effects elicited at the acupoint ae simila to those elicited at the sham point. This may help claify whethe acupoint specificity exists [Lao et al., 2001]. Howeve, to find a eal sham point on the human body is difficult. The designation of a eal acupoint is empiical: the 354 acupoints employed in the ninth centuy have gown to ove 2,000 today [Pomeanz, 1995; Shanghai College of Taditional Chinese Medicine, 1974; Zhu, 1997]. Many of the acupoints in use today wee unknown in ealie days. The potential effect of acupunctue at any somatic point is unknown until it is tested. Theefoe, what is selected as a nonpoint o sham point cannot be assumed to be inet o inactive just because it is not known to be active today. Moeove, clinical data showed acupunctue analgesia at sham points was effective in about 33 50% of patients with chonic pain, while tue points woked in about 55 85% [Richadson and Vincent, 1986; Vincent and Richadson, 1989]. Sham points can be used fo compaison with the eal points to detect possible similaities and/o diffeences, but they should not be consideed to be inet contol [Lund and Lundebeg, 2006]. This may at least patly explain the emakable ovelap of bain esponse among the sham point and the classical acupoints in ou study. The ovelap phenomenon was also obseved in pevious acupunctue studies [Fang et al., 2004; Kong et al., 2007a; Wu et al., 2002]. Cental Effects of Acupoint, Segmental Innevations, Tissue Type, and Meidian Oigin In ou study the thee acupoints ae located on two diffeent meidians and the sham point on a nonmeidian site. All of them ae supplied by simila segmental innevations (peoneal neve, L4 S1) [Chen, 1995; Cheng, 2000; Williams, 1995]. Hence, the similaity in segmental innevations could contibute to the similaities of cental effects on the bain in ou findings. Howeve, significant ovelap was also demonstated between LI4 on the hand and ST36 on the leg that have vey diffeent segmental innevations. It is poposed that the tissue type of the acupoint site may be an impotant facto on the cental effects of acupunctue [Fang et al., 2007; Hui et al., 2000, 2005]. The fou points in this study ae located in muscle/fibous connective tissue layes, with diffeences in popotions of the components. It is plausible that the geneal similaity in tissue type might contibute to simila cental effects with 1203

9 Fang et al. mino vaiations, an inteesting facto that deseves exploation. As fo the meidian oigin, thee was no enough evidence of a significant ole. The issue of acupoint specificity of cental effects equies futhe investigation. Limitations This study failed to povide definitive answes on the subject of acupoint specificity. Although poweful fo monitoing dynamic changes in the bain, ou fmri study only tested fo the acute hemodynamic esponse duing the shot peiod of acupunctue needling, not fo any delayed esponse that could occu with polonged o epeated stimulations. We did not assess physiological esponses, such as autonomic, endocine, and immunological functions that may diffe between acupoints. Moeove, bain imaging does not addess the changes that may be involved at the local level o at the spinal segmental level in acupunctue action [Gollub et al., 1999; Langevin et al., 2006; Li et al., 2004]. Impotantly, the effects of acupunctue on patients may diffe fom that on healthy subjects [Napadow et al., 2007]. The subjects in this study wee peselected to be espondes to acupunctue with an elevation of >10% in thei pain thesholds in a pesession acupunctue intevention. Thei hype-sensitivity to needle manipulation could be a facto fo the failue to show significant diffeences of the BOLD esponse between eal acupoint and sham point. The study design is exploatoy and the sample size is limited. Lage sample studies with geate statistical powe, on acupoints belonging to moe meidians, located in diffeent types of tissues and with diffeent innevations as well as a boade spectum of subjects in health and in disease ae equied fo the claification of acupoint specificity, given its impotance in TCM. CONCLUSIONS We found that the pattens of hemodynamic and psychophysical esponses to acupunctue stimulation at thee classical acupoints and a sham point wee geneally simila, with vaiations in the pefeential spatial distibutions at the global level. The chaacteistic patten of the hemodynamic esponse is extensive deactivation of a limbicpaalimbic-neocotical netwok that shows functional and stuctual connectivity. The antipain, antianxiety, and othe modulatoy effects of acupunctue may be mediated by this intinsic neual system. The specificity of acupoint effects equies futhe investigation. ACKNOWLEDGMENTS The authos would like to thank Vitaly Napadow Ph.D. fo his constuctive comments on the manuscipt. REFERENCES Becea LR, Beite HC, Stojanovic M, Fishman S, Edwads A, Comite AR, Gonzalez RG, Bosook D (1999): Human bain activation unde contolled themal stimulation and habituation to noxious heat: An fmri study. Magn Reson Med 41: Benedetti F, Aduino C, Amanzio M (1999): Somatotopic activation of opioid systems by taget-diected expectations of analgesia. J Neuosci 19: Biella G, Sotgiu ML, Pellegata G, Paulesu E, Castiglioni I, Fazio F (2001): Acupunctue poduces cental activations in pain egions. Neuoimage 14: Bingel U, Quante M, Knab R, Bomm B, Weille C, Buchel C (2002): Subcotical stuctues involved in pain pocessing: Evidence fom single-tial fmri. Pain 99: Buckne RL, Andews-Hanna JR, Schacte DL (2008): The bain s default netwok, anatomy, function and elevance to disease. Ann N Y Acad Sci 1124:1 38. Caia A, Veit R, Sitaam R, Lotze M, Weiskopf N, Godd W, Bibaume N (2007): Regulation of anteio insula cotex activity using eal-time fmri. Neuoimage 35: Camichael ST, Pice JL (1995): Limbic connections of the obital and medial pefontal cotex in macaque monkeys. J Comp Neuol 363: Cavanna AE, Timble MR (2006): The pecuneus: A eview of its functional anatomy and behavioual coelates. Bain 129: Chen E (1995): Coss-sectional anatomy of acupoints. Edinbugh: Chuchill Lvingstone. p Cheng XN (2000): Chinese Acupunctue and Moxibustion. Beijing: People s Medical Publishing House. Cho ZH, Chung SC, Jones JP, Pak JB, Pak HJ, Lee HJ, Wong EK, Min BI (1998): New findings of the coelation between acupoints and coesponding bain cotices using functional MRI. Poc Natl Acad Sci USA 95: Cho ZH, Na C, Wong EK, Lee S, Hong I (2000): Investigation of acupunctue using bain fmri. In: Litsche G, Cho Z, editos. Compute Contolled Acupunctue. Belin: Pabst Science Publishes. p Cho ZH, Chung SC, Lee HJ, Wong EK, Min BI (2006a): Retaction. New findings of the coelation between acupoints and coesponding bain cotices using functional MRI. Poc Natl Acad Sci USA 103: Cho ZH, Hwang SC, Wong EK, Son YD, Kang CK, Pak TS, Bai SJ, Kim YB, Lee YB, Sung KK, Lee BH, Shepp LA, Min KT (2006b): Neual substates, expeimental evidences and functional hypothesis of acupunctue mechanisms. Acta Neuol Scand 113: Davis KD, Kwan CL, Cawley AP, Mikulis DJ (1998): Functional MRI study of thalamic and cotical activations evoked by cutaneous heat, cold, and tactile stimuli. J Neuophysiol 80: Dhond RP, Kettne N, Napadow V (2007): Neuoimaging acupunctue effects in the human bain. J Alt Complem Med 13: Fang JL, Kings T, Weidemann J, Meiste IG, Thon A (2004): Functional MRI in healthy subjects duing acupunctue: Diffeent effects of needle otation in eal and false acupoints. Neuoadiology 46: Fang JL, Nixon E, Liu J, Hui KKS (2007): The limbic-cotical system and pain neuomatix: Deactivation by acupunctue, activation by pain - an fmri study at LV3. Abstact. Society fo Neuoscience 2007 Annual meeting in San Diego. Fang SH, Zhang SZ, Liu H, Shou YQ, Zhang QW, Cui HW, Hu XY (2006): Study on bain esponse to acupunctue by functional magnetic esounce imaging - Obsevation on 14 healthy subjects. Chin J Integ Med 26:

10 Acupunctue Modulates the Limbic System Fansson P (2006): How default is the default mode of bain function? Futhe evidence fom intinsic BOLD signal fluctuations. Neuopsychologia 44: Gaeus IK, Lacou M, Schulte AC, Hennig J (2002): Is thee a BOLD esponse of the visual cotex on stimulation of the vision-elated acupoint GB 37 J Magn Reson Imaging 15: Gollub R, Hui KKS, Stefano G (1999): Acupunctue: Pain management coupled to immune stimulation. Acta Phamacol. Sin 20: Gusnad DA, Akbudak E, Shulman GL, Raichle ME (2001): Medial pefontal cotex and self-efeential mental activity: Relation to a default mode of bain function. Poc Natl Acad Sci USA 98: Han JS, Teenius L (1982): Neuochemical basis of acupunctue analgesia. Ann Rev Phamacol Toxicol 22: Hsieh JC, Cheng FP, Tu CH, Tsai JS, Huang DF, Lee TY, Liu RS (1998): Bain activation by acupunctue with de-qi : a PET study. J Nuc Med 39:205. Hui KKS, Liu J, Kwong KK (1997a): Functional mapping of the human bain duing acupunctue with magnetic esonance imaging somatosensoy cotex activation. Wold J Acupunctue-Moxibustion 7: Hui KKS, Liu J, Chen AJ, Wu MT, Rosen BR, Kwong KK (1997b): Effects of acupunctue on human limbic system and basal ganglia measued by fmri. Neuoimage 5:S226. Hui KKS, Liu J, Chen AJ, Makis N, Gollub RL, Kennedy DN, Mooe CI, Rosen BR, Kwong KK (1998): Acupunctue modulates the limbic system and subcotical gay stuctues of the human bain-diect evidence by fmri. Neuoimage 7:S441. Hui KKS, Liu J, Makis N, Gollub RL, Chen AJ, Mooe CI, Kennedy DN, Rosen BR, Kwong KK (2000): Acupunctue modulates the limbic system and subcotical gay stuctues of the human bain: Evidence fom fmri studies in nomal subjects. Hum Bain Mapp 9: Hui KKS, Liu J, Maina O, Napadow V, Haselgove C, Kwong KK, Kennedy DN, Makis N (2005): The integated esponse of the human ceebo-ceebella and limbic systems to acupunctue stimulation at ST36 as evidenced by fmri. Neuoimage 27: Hui KKS (2007): Integated esponse of the human limbic system to acupunctue as evidenced by fmri. Poceedings 3d Intl Congess on Acupunctue, ICMART, Bacelona. Kong J, Ma L, Gollub RL, Wei J, Yang X, Li D, Weng X, Jia F, Wang C, Li F, Li R, Zhuang D (2002): A pilot study of functional magnetic esonance imaging of the bain duing manual and electoacupunctue stimulation of acupunctue point (LI-4 Hegu) in nomal subjects eveals diffeential bain activation between methods. J Alten Complement Med 8: Kong J, Gollub RL, Webb JM, Kong JT, Vangel MG, Kwong KK (2007a): Test-etest study of fmri signal change evoked by electoacupunctue stimulation. Neuoimage 34: Kong J, Kaptchuk T, Webb JM, Kong JT, Sasaki Y, Polich G, Vangel M, Kwong KK, Rosen B, Gollub RL (2007b): Functional neuoanatomical investigation of vision-elated acupunctue point specificity - a multi-session fmri study. Hum Bain Mapp: [Epub head of pint]. Kufahl P, Li Z, Risinge R, Rainey C, Piacentine L, Wu G, Bloom A, Yang Z, Li SJ (2007): Expectation modulates human bain esponses to acute cocaine: A functional magnetic esonance imaging study. Biol Psychiaty: [Epub ahead of pint]. Kwong KK, BelLVeau JW, Chesle DA, Goldbeg IE, Weisskoff RM, Poncelet BP, Kennedy DN, Hoppel BE, Cohen MS, Tune R, Cheng H, Bady TJ, Rosen BR (1992): Dynamic magnetic esonance imaging of human bain activity duing sensoy stimulation. Poc Natl Acad Med Sci USA 89: Langevin HM, Bouffad NA, Badge GJ, Chuchill DL, Howe AK (2006): Subcutaneous tissue fiboblast cytoskeletal emodeling induced by acupunctue: Evidence fo a mechanotansductionbased mechanism. J Cell Physiol 207: Lao LX, Ezzo J, Beman BMHR (2001): Assessing clinical efficacy of acupunctue: Consideations fo designing futue acupunctue tials. In: Stux G, Hammeschlag R, editos. Clinical acupunctue-scientific Basis. Belin: Spinge-Velag. p LeDoux JE (2000): Emotion cicuits in the bain. Annu Rev Neuosci 23: Li AH, Zhang JM, Xie YK (2004) Human acupunctue points mapped in ats ae associated with excitable muscle/skinneve complexes with eniched neve endings Bain Res 1012: Li G, Cheung RT, Ma QY, Yang ES (2003a): Visual cotical activations on fmri upon stimulation of the vision-implicated acupoints. Neuoepot 14: Li G, Liu HL, Cheung RT, Hung YC, Wong KK, Shen GG, Ma QY, Yang ES (2003b): An fmri study compaing bain activation between wod geneation and electical stimulation of language-implicated acupoints. Hum Bain Mapp 18: Liu WC, Feldman SC, Cook DB, Hung DL, Xu T, Kalnin AJ, Komisauk BR (2004): MRI study of acupunctue-induced peiaqueductal gay activity in humans. Neuoepot 15: Lund I, Lundebeg T (2006): Ae minimal, supeficial o sham acupunctue pocedues acceptable as inet placebo contols? Acupunct Med 24: Han JS (1999). Pinciples in neuoscience. Beijing: Publishing House of Beijing Medical Univesity. p Mill EK, Wallis JD (2002): The pefontal cotex and executive bain functions. In: Squie LR, Bloom FE, McConnell SK, Robets JL, Spitze NC, Zigmond MJ, editos. Fundamental Neuoscience. San Diego: Academic Pess. p Napadow V, Makis N, Liu J, Kettne NW, Kwong KK, Hui KKS (2005): Effects of electoacupunctue vesus manual acupunctue on the human bain as measued by fmri. Hum Bain Mapp 24: Napadow V, Kettne N, Liu J, Li M, Kwong KK, Vangel M, Makis N, Audette J, Hui KKS (2007): Hypothalamus and amygdala esponse to acupunctue stimuli in Capal Tunnel Syndome. Pain 130: NIH (1998): NIH Consensus Confeence. JAMA 280: Paish TB, Schaeffe A, Catanese M, Rogel MJ (2005): Functional magnetic esonance imaging of eal and sham acupunctue: Noninvasively measuing cotical activation fom acupunctue. IEEE Eng Med Biol Mag 24: Pavizi J, Van Hoesen GW, Buckwalte J, Damasio A (2006): Neual connections of the posteomedial cotex in the macaque. Poc Natl Acad Sci USA 103: Pomeanz B (1995): Scientific Basis of Acupunctue. New Yok: Spinge-Velag. Raichle ME, MacLeod AM, Snyde AZ, Powes WJ, Gusnad DA, Shulman GL (2001): A default mode of bain function. Poc Natl Acad Sci USA 98: Rainville P, Duncan GH, Pice DD, Caie B, Bushnell C (1997): Pain affect encoded in human anteio cingulate but not somatosensoy cotex. Science 277: Richadson PH, Vincent CA (1986): Acupunctue fo the teatment of pain: A eview of evaluative eseach. Pain 24:

11 Fang et al. Shanghai College of Taditional Chinese Medicine (1974). Acupunctue and Moxibustion. Beijing: People s Medical Publishing House. p Schnitzle A, Plone M (2000): Neuophysiology and functional neuoanatomy of pain peception. J Clin Neuophysiol 17: Shmuel A, Augath M, Oeltemann A, Logothetis NK (2006): Negative functional MRI esponse coelates with deceases in neuonal activity in monkey visual aea V1. Nat Neuosci 9: Shulman GL, Fiecz JA, Cobetta MC, Buckne RL, Miczin FM, Raichle M, Peteson S (1997): Common blood flow changes acoss visual tasks II, Deceases in ceebal cotex. J Cogn Neuosci 9: Simpson JR J., Devets WC, Snyde AZ, Gusnad DA, Raichle ME (2001): Emotion-induced changes in human medial pefontal cotex. II. Duing anticipatoy anxiety. Poc Natl Acad Sci USA 98: Stefanovic B, Wanking JM, Pike GB (2004): Hemodynamic and metabolic esponses to neuonal inhibition. Neuoimage 22: Sun YP, Fang JL, Nixon E, Liu J, Papadimitiou G, Maina O, Cavanagh G, Napadow V, Kwong KK, Vangel M, Kennedy DN, Makis N, Rosen BR, Hui KKS (2006): Dynamic esponse of the human bain to acupunctue at LV3 as monitoed by fmri: Evidence of limbic system modulation. Neuoimage 31:S161. Vincent JL, Snyde AZ, Fox MD, Shannon BJ, Andews JR, Raichle ME (2006): Coheent spontaneous activity identifies a hippocampal-paietal memoy netwok. J Neuophysiol 96: Vincent PA, Richadson PH (1989): The significance of needle placement site in acupunctue. J Psychosom Res 33: Vogt BA, Vogt L, Laueys S (2006): Cytology and functionally coelated cicuits of human posteio cingulate aeas. Neuoimage 29: Wang W, Liu L, Zhi X, Huang JB, Liu DX, Wang H, Kong XQ, Xu HB (2007): Study on the egulatoy effect of electo-acupunctue on hegu point (LI4) in ceebal esponse with functional magnetic esonance imaging. Chin J Integ Med 13: Williams PL (1995): Gacy s Anatomy. Edinbugh: Chuchill LVingstone. p Wu MT, Hsieh JC, Xiong J, Yang CF, Pan HB, Chen YC, Tsai G, Rosen BR, Kwong KK (1999): Cental nevous pathway fo acupunctue stimulation: Localization of pocessing with functional m imaging of the bain-peliminay expeience. Radiology 212: Wu MT, Sheen JM, Chuang KH, Yang P, Chin SL, Tsai CY, Chen CJ, Liao JR, Lai PH, Chu KA, Pan HB, Yang CF (2002): Neuonal specificity of acupunctue esponse: A fmri study with electoacupunctue. Neuoimage 16: Yan B, Li K, Xu J, Wang W, Li K, Liu H, Shan B, Tang X (2005): Acupoint-specific fmri pattens in human bain. Neuosci Lett 383: Yoo SS, Teh EK, Blinde RA, Jolesz FA (2004): Modulation of ceebella activities by acupunctue stimulation: Evidence fom fmri study. Neuoimage 22: Zhang WT, Jin Z, Cui GH, Zhang KL, Zhang L, Zeng YW, Luo F, Chen AC, Han JS (2003): Relations between bain netwok activation and analgesic effect induced by low vs. high fequency electical acupoint stimulation in diffeent subjects: A functional magnetic esonance imaging study. Bain Res 982: Zhang WT, Jin Z, Luo F, Zhang L, Zeng YW, Han JS (2004): Evidence fom bain imaging with fmri suppoting functional specificity of acupoints in humans. Neuosci Lett 354: Zubieta JK, Smith YR, Buelle JA, Xu Y, Kilboun MR, Jewett DM, Meye CR, Koeppe RA, Stohle CS (2001): Regional mu opioid ecepto egulation of sensoy and affective dimensions of pain. Science 293: Zhu B (1997): Scientific Foundations Of Acupunctue & Moxibustion. Qingdao: Qinadao Publishing House. 1206