生物谷报道：王锦琰、罗非等人最近的一项研究揭示了疼痛的反馈调节机制的特性。疼痛是一种多维度现象，它在大脑中激活的是神经网络，而不是零星的脑区。人们越来越多的认识到，脊髓以上水平的脑机制在疼痛的表达和调节过程中发挥着重要作用。王锦琰、罗非等人通过观察与疼痛相关的信息流和丘脑－皮层通路中的神经元的相互联系研究了疼痛过程中皮层和丘脑在功能上的相互作用。研究者将微电极阵列植入大鼠四个不同的脑区：初级躯体感觉皮层(SI)，前扣带回皮层(ACC)，丘脑腹后核(VP)和丘脑背内侧核(MD)，在大鼠清醒状态下，给后肢足底施加辐射热伤害性刺激。结果显示，在上述四个脑区记录到大量的反应神经元。研究者运用先进的生物信息分析手段——定向相干分析揭示了在伤害性刺激后脑内神经信息流的改变，即从皮层(SI)到丘脑(VP)的信息量显著增多，这表明在疼痛编码过程中皮层对丘脑神经元有自上而下的影响。同时，交互相关分析显示，在疼痛刺激下皮层和丘脑神经元之间的联系显著增强，更为重要的是，皮层神经元先于丘脑神经元放电，这与定向相干分析的结果非常的一致。基于以上发现，王锦琰，罗非等人提出，痛觉信息在脑内传递的过程中是受到皮层－丘脑反馈机制调节的，这种调节主要体现在在疼痛的感觉(而非情绪)通路上。这项研究对于认识疼痛的中枢调节机制作出了重要贡献，对于痛觉的形成和治疗具有重要的理论和临床意义。
研究结果论文Corticofugal influences on thalamic neurons during nociceptive transmission in awake rats. 已发表在《突触》（）上。
原始出处:
Synapse 2007, 61: 335-342
Research Article
Corticofugal influences on thalamic neurons during nociceptive transmission in awake rats
Jin-Yan Wang 1, Jing-Yu Chang 2, Donald J. Woodward 3, Luiz A. Baccalá 4, Ji-Sheng Han 5, Fei Luo 1 *
1Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
2Department of Physiology and Pharmacology, Wake Forest University Health Science, Winston-Salem, North Carolina
3Neuroscience Research Institute of North Carolina, Winston-Salem, North Carolina
4Telecommunications and Control Engineering, Escola Politecnica, University of Sao Paulo, Sao Paulo, Brazil
5Neuroscience Research Institute, Peking University, Beijing, China
email: Fei Luo (luof@psych.ac.cn)
*Correspondence to Fei Luo, Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, 10A Datun Road, Chaoyang District, Beijing 100101, People's Republic of China
Funded by:
National Natural Science Foundation of China; Grant Number: 30170307, 30370461, 30570577
Ministry of Education of China; Grant Number: 985-2-068-113
Ministry of Science and Technology of China; Grant Number: 2003CB515407
NIH; Grant Number: NS-43441, NS-40628, TW-06144, NS-19608
Keywords
cortex ?cingulate ?thalamus ?nociception ?crosscorrelation ?information flow
Abstract
Pain is a multidimensional phenomenon and processed in a neural network. The supraspinal, brain mechanisms are increasingly recognized in playing a major role in the representation and modulation of pain. The aim of the current study is to investigate the functional interactions between cortex and thalamus during nociceptive processing, by observing the pain-related information flow and neuronal correlations within thalamo-cortical pathways. Pain-evoked, single-neuron activity was recorded in awake Sprague-Dawley rats with a Magnet system. Eight-wire microarrays were implanted into four different brain regions, i.e., the primary somatosensory (SI) and anterior cingulate cortex (ACC), as well as ventral posterior (VP) and medial dorsal thalamus (MD). Noxious radiant heat was delivered to the rat hind paws on the side contralateral to the recording regions. A large number of responsive neurons were recorded in the four brain areas. Directed coherence analysis revealed that the amount of information flow was significantly increased from SI cortex to VP thalamus following noxious stimuli, suggesting that SI cortex has descending influence on thalamic neurons during pain processing. Moreover, more correlated neuronal activities indicated by crosscorrelation histograms were found between cortical and thalamic neurons, with cortical neurons firing ahead of thalamic units. On basis of the above findings, we propose that nociceptive responses are modulated by corticothalamic feedback during nociceptive transmission, which may be tight in the lateral pathway, while loose in the medial pathway. Synapse 61:335-342, 2007. © 2007 Wiley-Liss, Inc.
