基于功能性磁共振成像技术的运动疲劳“中枢控制器模型”理论在体研究

The Central Governor Model Theory of Exercise Fatigue in Human Body:An fMRI Study

目的:“中枢控制器模型”理论主张大脑是运动疲劳的关键调节器,而小脑和基底节为2个主要调定点,该假说为探究运动疲劳的中枢影响机制提供了新的理论基础和研究方向,但受限于研究手段一直无法在人体中得到验证。本研究拟通过功能性磁共振成像(functional magnetic resonance imaging,fMRI)技术探究与运动疲劳相关的大脑区域以及相应脑区之间的激活与功能连接状态,从而验证人体运动疲劳的“中枢控制器模型”理论。方法:招募20名800 m跑成绩≤2 min 3 s的男性运动员,对其进行最大摄氧量测试,根据测试结果最终遴选出相对最大摄氧量≥55 ml/(kg·min)的11名被试。实验前使用氢质子磁共振波谱(1H-magnetic resonance spectroscopy,1H-MRS)测试被试静息态脑区代谢物质的浓度;使用全脑血氧水平依赖功能磁共振成像(blood oxygen level dependent-functional Magnetic Resonance Imaging,BOLD-fMRI)测试被试静息态脑功能网络连接。随后进行递增负荷运动至疲劳实验,试达到疲劳状态后即刻进行与实验前一致的fMRI测试。结果:通过1H-MRS测试发现,运动疲劳发生后被试左侧基底节区(basal ganglia,BG)的Cho/Cr显著降低(P<0.05);通过BOLD-fMRI发现运动员递增负荷运动至疲劳后小脑(cerebellum)和初级运动区(primary motor areas,M1)、小脑和躯体感觉运动区(sensory motor cortex,SMC)、小脑和海马(hippocampus)/海马旁回(parahippocompalgyrus)之间的功能网络连接程度减弱(P<0.05)。结论:运动疲劳发生后基底节区的代谢物质下降,以小脑为中心的脑功能默认网络连接降低,基底节区和小脑可能是使人体出现运动疲劳状态的重要脑功能区,也初步验证了基底神经节和小脑作为2个监视系统来调控人体产生运动疲劳的“中枢控制器模型”理论假说。

Objective:The“central governor model”theory suggests that the brain is the key regulator of exercise fatigue,with the cerebellum and basal ganglia as the two main regulating points.this hypothesis provided a new theoretical basis and research direction to explore the central mechanisms of exercise fatigue,but it was unable to be tested in humans due to the limitations of research methods.This study aimed to investigate the activation and functional connectivity of brain regions associated with exercise fatigue through functional Magnetic Resonance Imaging(fMRI),so as to verify the“central governor model”theory of exercise fatigue in humans.Methods:Twenty male athletes whose 800 m running result was less than 2 minutes 3 seconds were recruited in this study,after a maximal oxygen uptake test,11 subjects with relative maximal oxygen uptake≥55 ml/min were selected for further experiments.The participants completed a 1H-magnetic resonance spectroscopy(1H-MRS)and whole-brain blood oxygen level dependent-functional magnetic resonance imaging(BOLD-fMRI)scan at baseline and immediately after the aerobic circle ergometer test.Results:1H-MRS showed a significant decrease in Cho/Cr in the left basal ganglia(BG)after exercise fatigue(P<0.05);BOLD-fMRI showed a significant decrease of functional network connections between the cerebellum and primary motor areas(M1),cerebellum and sensorimotor cortex(SMC),cerebellum and hippocampus/parahippocampus(P<0.05).Conclusion:The metabolic substances in the basal ganglia is dreased after exercise fatigue,and the functional network connectivity between the cerebellum and other brain region is decreased as well.The basal ganglia and cerebellum could be important regions that contribute to exercise fatigue in humans,and the“central governor model”is preliminary verified in this study.