Wolpaw J R
Wadsworth Center for Laboratories and Research, New York State Department of Health, Albany.
Med Sci Sports Exerc. 1994 Dec;26(12):1475-9.
The spinal stretch reflex (SSR), or tendon jerk, is the simplest behavior of the vertebrate nervous system. It is mediated primarily by a wholly spinal, two-neuron pathway. Recent studies from several laboratories have shown that primates, human and nonhuman, can gradually increase or decrease the size of the SSR when reward depends on such change. Evidence of this training remains in the spinal cord after all supraspinal influence is removed. Thus, the learning of this simple motor skill changes the spinal cord itself. Comparable spinal plasticity probably plays a role in the acquisition of many complex motor skills. Intracellular physiological and anatomical studies are seeking the location and nature of this spinal cord plasticity. Attention focuses on the most probable sites of change, the group Ia afferent synapse on the alpha motoneuron and the motoneuron itself. Results to date indicate that modifications are present at several places in the spinal cord. Current clinical studies are investigating the use of spinal cord adaptive plasticity as a basis for a new therapeutic approach to spasticity and other forms of abnormal spinal reflex function that result from spinal cord injury, stroke, or other neurological disorders. In the future, understanding of spinal reflex plasticity may lead to development of improved training methods for a variety of motor skills.
脊髓牵张反射（SSR），即腱反射，是脊椎动物神经系统最简单的行为。它主要由一条完全位于脊髓的双神经元通路介导。几个实验室最近的研究表明，无论是人类还是非人类的灵长类动物，当奖励取决于这种变化时，都可以逐渐增加或减小SSR的大小。在去除所有脊髓以上的影响后，这种训练的证据仍保留在脊髓中。因此，这种简单运动技能的学习改变了脊髓本身。类似的脊髓可塑性可能在许多复杂运动技能的习得中发挥作用。细胞内生理学和解剖学研究正在寻找这种脊髓可塑性的位置和性质。注意力集中在最可能发生变化的部位，即α运动神经元上的Ia类传入突触和运动神经元本身。迄今为止的结果表明，脊髓的几个部位都存在改变。目前的临床研究正在探讨将脊髓适应性可塑性作为一种新的治疗方法的基础，用于治疗因脊髓损伤、中风或其他神经系统疾病导致的痉挛和其他形式的异常脊髓反射功能。未来，对脊髓反射可塑性的理解可能会带来各种运动技能训练方法的改进。
