【作者】 包大鹏；

【导师】 矫玮；

【作者基本信息】 北京体育大学 ， 运动人体科学， 2012， 博士

【摘要】 目的：本文旨在通过功能核磁成像技术研究运动疲劳和力竭后脑功能的变化,探讨其运动性中枢疲劳的特征。方法：根据V02max测试及800米成绩筛选男子运动员11名(20.27±0.79y,rV02max=60.05±3.30),测试静息态下M1与基底节进行H1-MRS核磁共振体质子波谱分析,ASL及ASE序列fMRI测试运动员全脑CBF及OEF,扫描运动员BOLD-fMRI静息态。疲劳实验起始负荷为90W,每2分钟递增30W自行车运动至疲劳后即刻进行上述fMRI测试,力竭实验以VT强度持续自行车运动至力竭即刻进行上述fMRI测试。结果：1、运动性疲劳发生后左侧基底节区的Cho/Cr由1.14±0.50降至0.69±0.51(P<0.05),力竭发生后左侧基底节区NAA/Cr由1.79±0.81升至2.78±1.82(P<0.01)。2、疲劳后全脑CBF由静息态58.05±7.91ml/100g/min降至52.30±7.30ml/100g/min(p<0.01)；右侧额下回、左侧颞中回、左右纹状体的rCBF下降(P<0.01)而OEF未变化(P>0.05)：力竭后全脑CBF由静息态58.05±7.91(ml/100g/min)降至53.51±6.38(ml/100g/min)；右侧额下回和左侧前扣带回腹侧的rCBF下降(P<0.01)而OEF未变化(P>0.05)。3、疲劳后M1区和小脑、SMC和小脑、海马／海马旁回和小脑之间的静息态功能连接减弱；力竭后SMC区和小脑、海马旁回和小脑、额叶和小脑静息态功能连接减弱。结论：1、运动性疲劳后出现左侧基底节代谢物Cho/Cr下降,且与有氧运动能力呈负相关,可能是运动性疲劳的限制因素；运动性力竭后左侧基底节代谢物NAA/Cr升高,且与有氧运动能力呈负相关,可能是运动性力竭的限制因素。2、运动性疲劳后运动员全脑及右侧额下回、左右纹状体和左侧颞中回的rCBF减少；力竭后右侧额下回和左侧前扣带回的rCBF减少；随着运动时间延长、强度增加,右侧额下回的rCBF下降越明显；上述核团的rCBF减少、OEF未变化而导致的CMR02降低可能是运动性中枢疲劳原因。3、运动员静息态时形成以小脑为中心的脑功能默认连接网络,疲劳或力竭发生后功能连接降低。更多还原

【Abstract】 Purpose:This study aim to probe the characteristics of central fatigue during exercise with the investigation and analysis of the change in brain function of subjects in fatigue and in exhaustion by f-MRIMethods:In this study,11male athletes (20.27±0.79y, rV02max=60.05±3.30) were chosen according to the results of maximal oxygen uptake experiment and the performance of800-meter race. H1-MRS was utilized to analyze the proton spectrum in M1and basal ganglia of the subjects in resting state and the whole brain CBF and OEF of athletes were gained with ASL and ASE sequences. Meanwhile, BOLD-fMRI was also carried out to scan the brain of participants in resting state. In fatigue exercise, subjects were asked to drive the ergo bicycle with an initial load of90W and30W increment every2minutes till fatigue exists. Another one were required to do the power cycling at the intensity of VT and the speed of60±5r/min till exhaustion. MRI scans as mentioned above were utilized immedietlly.Results:1. After exercise-induced fatigue happened, the Cho/Cr in the left basal ganglia of subjects decreased from1.14±0.50to0.69±0.51(P<0.05), after the exercise-induced exhaustion existed, the NAA/Cr in the left M1increased from1.79±0.81to2.78±1.82(P<0.01).2. The whole brain CBF dropped from58.05±7.91ml/100g/min to52.30±7.30ml/100g/min(p<0.01) in addition to the falling of rCBF in right inferior frontal gyrus, left middle temporal gyrus, left and right striatum (P<0.01) while there is no change in OEF in the fatigue state. On the other hand, the whole brain CBF went down from58.05±7.91(ml/100g/min) in resting state to53.51±6.38(ml/100g/min) and the CBF of Right inferior frontal gyrus and ventral of left anterior cingulate also reduced (P<0.01) while on changes of OEF happened (p>0.05) in the exhaustion state after moderate-intensity exercise.3. Compared to resting state, the functional connectivity between M1and SMC and Cerebellum, hippocampus/parahippocampal and cerebellar network brain regions weakened after fatigue while the functional connectivity between somatosensory motor area and cerebellum, parahippocampal gyrus and cerebellum, frontal lobe and cerebellar network brain regions became weak after exhaustion.Conclusions:Based on the results above, it could be found that1. The increment of NAA/Cr in both side of the basal ganglia and Cho/Cr in the left Ml is the restricting factor of exercise-induced pump while the ascent of Cho/Cr in the right M1and Cho/Cr in the left basal ganglia is the constraints of exercise-induced fatigue;2. The drop of CMRO2, which is caused by the decrement of rCBF in right inferior frontal gyrus, left middle temporal gyrus and left and right striatum accompanied with the stability of OEF, is one of central influences on exercise-induced fatigue. Meanwhile, the drop of CMRO2, which is caused by the decrement of CBF in right inferior frontal gyrus and the ventral of left anterior cingulate accompanied with the stability of OEF, is one of central influences on exercise-induced exhaustion.3. In the resting state, the cerebellum is the center of all the default network of brain regions of athletes, which forms a steady network system, of which the functional connectivity drops in the fatigue or exhaustion states.更多还原