力竭运动过程中大鼠苍白球内侧部对皮层的调控作用

目的:探讨力竭运动中大鼠苍白球内侧部对皮层的调控作用。方法:采用皮层脑电(ECoG)及局部场电(LFPs)同步记录技术,动态观察一次性力竭运动中大鼠皮层辅助运动区、苍白球内侧部神经元电活动变化规律。结果:运动开始阶段,大鼠能够自主跟随跑台进行运动,持续约43 min(43±11.8 min)后,大鼠自主运动能力明显降低,此时,皮层神经元功率谱重心频率显著降低(P<0.01),提示神经元兴奋性下降,而苍白球内侧部神经元功率谱重心频率显著升高(P<0.01),提示兴奋性增强;此时给予大鼠一定的外部刺激,大鼠仍可继续运动一段时间直至力竭,皮层神经元功率谱重心频率降至最低(P<0.01),而苍白球内侧部神经元功率谱重心频率达到最高(P<0.01)。力竭运动过程中,苍白球内侧部局部场电活动与皮层脑电活动呈相反变化趋势,且不同阶段两区域神经元在0~30Hz范围内均显著相干。结论:力竭运动过程中苍白球内侧部神经元兴奋性增强经丘脑中继后对皮层神经元产生去兴奋作用,是导致疲劳及运动能力下降的重要因素之一,提示苍白球内侧部-丘脑-皮层通路在运动疲劳产生过程中起重要调控作用。

Modulatory Effect of the Internal Segment of Globus Pallidus on Motor Cortex Activity during Exhaustive Exercise

Objective To observe the effect of the internal segment of globus pallidus(GPi) on motor cortex activity during exhaustive exercise. Methods Electrocorticogram (ECoG) and local field potentials (LFPs) recordings were applied simultaneously to observe the dynamic changes of oscillations in supplementary motor area (SMA) and GPi of rats during exhausting exercise. Results After average 43min (43 ±11.8 min) running on a treadmill,exercise capacity of the rats decreased,the gravity frequency (fg) in ECoG decreased significantly (P < 0.01),while the f g of GPi activity increased significantly(P < 0.01). Rats were forced to run under the moderate external stimulation till exhaustion, when f g of cortex decreased to minimum (P < 0.01),and f g of GPi increased to maximum (P < 0.01). However,neural activity of cortex and GPi changed in a contrary way during exhaustive exercise. Significant coherence between cortex and GPi within the range of 0～30 Hz was observed. Conclusions The increased neural activity in GPi reveals inhibitive effect on the cortex electrical activity through the thalamus during exhausting exercise,indicating that "GPi-thalamus-cortex" pathway plays an important role in the process of exercise-induced fatigue.