Characteristic Of Sustained Neural Responses Following Acupuncture

Acupuncture, as a treasure of the splendid traditional culture of Chinese nations, possesses massive health resources with characters and advantages in Chinese medical and health care undertakings. Because of the globally increasing medical expenditure and the iatrogenic and drug-induced diseases caused by modern medication in conquering hazardous diseases, the medical community and patients are becoming very interested in the economic, low toxic and side-effect acupuncture subsectioned in Traditional Chinese Medicine good at regulation. The traditional Chinese Medicine of acupuncture theories, growing out of practices and deeply processed by Chinese classical philosophy, make it hard to reconcile with modern medicines in many aspects, which sets up shackles for the development of acupuncture theories. With the advanced development of the modern neuroimaging techniques, particularly the functional magnetic resonance imaging (fMRI), the exploration of the relations among acupoints, brain and viscera has become possible. The fMRI technique, with its non-invasive and higher resolution characterstics, has been widely applied in the detection of the brain functions. However, the fMRI acupuncture investigation is still in its early stage, and needs further improvements.Previous neuroimaging acupuncture studies have mainly focused on the correlations between acupuncture at certain acupoint and the functional brain cortice, as the spatially localized studies. According to the Traditional Chinese Medicine and abundant clinical evidence, the effect of acupuncture can sustain beyond the needle manipulation period. Therefore, the consideration of temporal information of the central nervous system in acupuncture bears vital theoretical importance in the deep understading of acupuncture mechanism. This paper, with the verification of acupuncture sustained effect hypothesis as the breakthrough point and through the multi-block design, confirmed the existence of the prolonged effects of acupuncture, demonstrated the fact that previous model-based multi-block studies violated the baseline princinple in the substracte technique reckoning without temporal information, and caused the errors of experiment results; next, the article adopted the new non-repeted event-related experiment paradigm and dynamic detection algorithm to construct the dynamic neutral response to acupuncture, and then the author speculated that acupuncture action involved participation of multi-neuro brain networks; further, we employed the spontaneous oscillation network analysis to investigate the intergrated mechanism of these dynamic nuclei responses induced by acupuncture, and advanced the nervous representation of the anti-correlated brain networks to doubt the dominant decreased limbic-system theory of acupuncture; finally, for the purpose of explaination about the real physiological mechanism of the nervous representation of sustained effects of acupuncture, we constructed the disgust affective model and combined the fMRI data with physiological indices to explore both the neural modulatory and the potential physiological mechanism underlying the longer-lasting effects of acupuncture. The details of the design paradigms and corresponding results are listed as follows:The first experiment"the validation of the sustained effects of acupuncture by the multi-block design"aimed to validate the hypothesis about the sustained effects of acupuncture. To achieve this goal, we designed separate models to evaluate the baseline activities (prior to stimulation) and neural activities in sequential epochs via the block-designed paradigm to confirm the existence of the prolonged effects of acupuncture. This finding indicated that previous studies violate the baseline princinple in the substracte technique and may cause errors of experiment results, which make the model-based multi-block designed analysis improper in acupuncture studies.The second experiment"the construction of the time-varying neural responses model of the sustained effects of acupuncture"attempted to construct the time-varying neural responses to the sustained effects of acupuncture. We introduced the non-repeated event-related design and hierarchical exponentially weighted moving-average method to investigate the temporal characteristics of neural responses to acupuncture. Resullts showed that acupuncture can evoke the complex time-dependent neural responses, and an accurate interpretation of acupuncture actions depended on how effectively we can characterize the nature of temporal variations underlying neural activities that give rise to hemodynamic responses, rather than simply detect the occurrence of such changes.The third experiment"the proposed hypothesis of the anti-correlated brain networks following acupuncture and the doubt of the hypothesis of the dominant decreased limbic-system theory", employed the non-repeated event-related design and spontaneous oscillation network analysis to investigate the intergrated processing mechanism of the dynamic neural responses induced by acupuncture. Its findings demonstrated the sustained effects of acupuncture can achieve the intergrated processing mechanism through the anti-correlated organization mechanism of brain networks, rather than exert unidirectional modulatory effects on human brain. Therefore, we made concluded doubt of the dominant theory of decreased limbic-system following acupuncture.The fourth experiment"the construction of neural pathways and physiological mechanism of the prolonged effects of acupuncture"constructed the novel disgust affective model and realized the effective control of experimental factors and individual functional differences,with respect of the deficient control of experimental factors, low consistency of analysis results, and lack of real understanding of acupuncture modulatory pathways; it also validated the existence of sustained effects of acupuncture, and investigated the modulatory mechanism on this disgust affective model and the potential physiological mechanism, after acupuncturing at different acupoints,by ways of combined method of fMRI data and physiological indices. Our findings indicated that acupuncture at different acupoints can cause selective modulatory effects on the disgust affective model, which have high relations to the changes of physiological disgust and anxiety indices. According to these observations, we inferred that acupuncture can exert the function-guided neural modulatory mechanisms. This investigation can not only disclose the complex multiple system effects underlying the acupuncture, but also provide meaningful theoretical evidence for the clinical applications of acupuncture neuroimaging.