Adkins DeAnna L, Boychuk Jeffery, Remple Michael S, Kleim Jeffrey A
Brain Rehabilitation Research Center, Malcom Randall Veterans Affairs Hospital, Gainesville, FL, USA.
J Appl Physiol (1985). 2006 Dec;101(6):1776-82. doi: 10.1152/japplphysiol.00515.2006. Epub 2006 Sep 7.
The motor cortex and spinal cord possess the remarkable ability to alter structure and function in response to differential motor training. Here we review the evidence that the corticospinal system is not only plastic but that the nature and locus of this plasticity is dictated by the specifics of the motor experience. Skill training induces synaptogenesis, synaptic potentiation, and reorganization of movement representations within motor cortex. Endurance training induces angiogenesis in motor cortex, but it does not alter motor map organization or synapse number. Strength training alters spinal motoneuron excitability and induces synaptogenesis within spinal cord, but it does not alter motor map organization. All three training experiences induce changes in spinal reflexes that are dependent on the specific behavioral demands of the task. These results demonstrate that the acquisition of skilled movement induces a reorganization of neural circuitry within motor cortex that supports the production and refinement of skilled movement sequences. We present data that suggest increases in strength may be mediated by an increased capacity for activation and/or recruitment of spinal motoneurons while the increased metabolic demands associated with endurance training induce cortical angiogenesis. Together these results show the robust pattern of anatomic and physiological plasticity that occurs within the corticospinal system in response to differential motor experience. The consequences of such distributed, experience-specific plasticity for the encoding of motor experience by the motor system are discussed.
运动皮层和脊髓具有非凡的能力，能够根据不同的运动训练改变结构和功能。在此，我们综述相关证据，即皮质脊髓系统不仅具有可塑性，而且这种可塑性的性质和位点由运动体验的具体情况所决定。技能训练可诱导运动皮层内的突触形成、突触增强以及运动表征的重组。耐力训练可诱导运动皮层血管生成，但不会改变运动图谱组织或突触数量。力量训练可改变脊髓运动神经元的兴奋性，并诱导脊髓内的突触形成，但不会改变运动图谱组织。所有这三种训练体验都会诱导脊髓反射的变化，这些变化取决于任务的特定行为需求。这些结果表明，熟练运动的习得会诱导运动皮层内神经回路的重组，从而支持熟练运动序列的产生和完善。我们提供的数据表明，力量的增加可能是由脊髓运动神经元激活和/或募集能力的增强介导的，而与耐力训练相关的代谢需求增加会诱导皮质血管生成。这些结果共同表明，皮质脊髓系统内会因不同的运动体验而出现强大的解剖学和生理学可塑性模式。我们还讨论了这种分布式、特定于体验的可塑性对运动系统编码运动体验的影响。
