title: Investigation of acupoint specificity by multivariate granger causality analysis from functional MRI data.
abstract: OBJECTIVE
  To investigate the acupoint specificity by exploring the effective connectivity patterns of the poststimulus resting brain networks modulated by acupuncture at the PC6, with the same meridian acupoint PC7 and different meridian acupoint GB37.
  
  
  METHODS
  The functional MRI (fMRI) study was performed in 36 healthy right-handed subjects receiving acupuncture at three acupoints, respectively. Due to the sustained effects of acupuncture, a novel experimental paradigm using the nonrepeated event-related (NRER) design was adopted. Psychophysical responses (deqi sensations) were also assessed. Finally, a newly multivariate Granger causality analysis (mGCA) was used to analyze effective connectivity patterns of the resting fMRI data taken following acupuncture at three acupoints.
  
  
  RESULTS
  Following acupuncture at PC6, the red nucleus and substantia nigra emerged as central hubs, in comparison with the fusiform gyrus following acupuncture at GB37. Red nucleus was also a target following acupuncture at PC7, but with fewer inputs than those of PC6. In addition, the most important target following acupuncture at PC7 was located at the parahippocampus.
  
  
  CONCLUSIONS
  Our findings demonstrated that acupuncture at different acupoints may exert heterogeneous modulatory effects on the causal interactions of brain areas during the poststimulus resting state. These preliminary findings provided a clue to elucidate the relatively function-oriented specificity of acupuncture effects.
authors.affiliation: Key Laboratory of Complex Systems and Intelligence Science, Institute of Automation, Chinese Academy of Sciences, Beijing, China.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Feng
authors.forename: Lijun
authors.initials: L
authors.lastname: Bai
authors.forename: Wensheng
authors.initials: W
authors.lastname: Zhang
authors.forename: Ting
authors.initials: T
authors.lastname: Xue
authors.forename: Yanshuang
authors.initials: Y
authors.lastname: Ren
authors.forename: Chongguang
authors.initials: C
authors.lastname: Zhong
authors.forename: Hu
authors.initials: H
authors.lastname: Wang
authors.forename: Youbo
authors.initials: Y
authors.lastname: You
authors.forename: Zhenyu
authors.initials: Z
authors.lastname: Liu
authors.forename: Jianping
authors.initials: J
authors.lastname: Dai
authors.forename: Yijun
authors.initials: Y
authors.lastname: Liu
authors.forename: Jie
authors.initials: J
authors.lastname: Tian
mesh_terms: D015669:Acupuncture Points; D015670:Acupuncture Therapy / Q000379:methods*; D000328:Adult; D001921:Brain / Q000473:pathology*; D001931:Brain Mapping / Q000379:methods*; D005260:Female; D006624:Hippocampus / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D015233:Models, Statistical; D015999:Multivariate Analysis; D012012:Red Nucleus / Q000502:physiology; D015203:Reproducibility of Results