Motoneurones "learn" and "forget" physical activity
Motoneurones "learn" and "forget" physical activity
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DOI：
10.1139/h05-127
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发表时间：
2005-06-01
期刊：
影响因子：
--
通讯作者：
Cormery, B
中科院分区：
文献类型：
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作者：
Gardiner, P;Beaumont, E;Cormery, B
尽管我们知道棘上神经元和骨骼肌的活动相关适应，但α-运动神经元对慢性活动水平改变的适应知之甚少。最近的证据表明，α-运动神经元的生物物理特性具有可塑性，可以适应慢性激活的增加和减少。适应性的本质——静息膜电位、尖峰阈值、后超极化振幅和尖峰产生期间的去极化率——指向运动神经元膜中离子电导通道的密度、类型、位置和/或代谢调节。这些变化将对运动神经元在运动产生过程中被激活时的反应，以及在长时间运动中维持激活所需的努力产生重大影响。由于这种适应很可能涉及运动神经元的结构变化和蛋白质合成的变化，并改变细胞对输入的输出反应，因此它们被认为是学习反应。展望了该问题未来的研究方向。
In spite of our knowledge of activity related adaptations in supraspinal neurones and skeletal muscles, very little is known concerning adaptations in α-motoneurones to alterations in chronic activity levels. Recent evidence shows that the biophysical properties of α-motoneurones are plastic and adapt to both increases and decreases in chronic activation. The nature of the adaptations-in resting membrane potential, spike threshold, afterhyper-polarization amplitude, and rate of depolarization during spike generation-point to involvement of density, type, location, and/or metabolic modulation of ion conductance channels in the motoneuronal membrane. These changes will have significant effects on how motoneurones respond when activated during the generation of movements, and on the effort required to sustain activation during prolonged exercise. Since the adaptations most likely involve structural changes in the motoneurones and changes in protein synthesis, and change the output response of the cells to input, they are considered to be learning responses. Future research directions for examining this issue are outlined.