02070nas a2200241   4500008004100000022001400041245009400055210006900149260001200218300001600230490000700246520139200253653001701645653001301662653001101675653001801686653001501704653001201719653001601731653001301747100002101760856004701781       1994                        eng d  a0195-913100aAcquisition and maintenance of the simplest motor skill: investigation of CNS mechanisms.0 aAcquisition and maintenance of the simplest motor skill investig  c12/1994  a1475–14790 v263 aThe 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.10aconditioning10aLearning10aMemory10aMotor control10aplasticity10aprimate10aSpinal Cord10atraining1 aWolpaw, Jonathan  uhttp://www.ncbi.nlm.nih.gov/pubmed/7869882