Effects of short-term training on sensory and motor function in severed nerves of long-term human amputees
Effects of short-term training on sensory and motor function in severed nerves of long-term human amputees
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DOI：
10.1152/jn.00937.2004
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发表时间：
2005-05-01
影响因子：
2.5
通讯作者：
Horch, KW
中科院分区：
文献类型：
--
作者：
Dhillon, GS;Krüger, TB;Horch, KW
关于截肢等事件引发的人类中枢神经系统的可塑性变化，已经有很多研究和报道。然而，很少有人知道在何种程度上原始通路保留残余功能后，外周截肢。我们早期对长期截肢者的急性研究表明，与周围神经截肢相关的中枢通路至少保留了一些感觉和运动功能。本研究的目的是确定这些功能连接是否会随着几天的经验和训练而得到加强或改善。为此，将电极植入长期人类截肢者的切断神经束内，以评估与尝试幻肢运动相关的电诱发感觉和意志运动神经元活动的变化。神经刺激一致地导致离散的、单一的、分级的触摸/压力感觉和关节位置感觉。随着时间的推移，产生这些感觉所需的刺激参数值没有显著变化。同样，虽然截肢者能够改善运动神经元活动的意志控制，但变化的速度和模式与正常人在运动任务中的练习相似。我们的结论是，截肢后看到的中央可塑性最有可能主要是由于暴露，而不是更换，现有的突触连接。这些结果也对假肢的神经控制产生了影响。
Much has been studied and written about plastic changes in the CNS of humans triggered by events such as limb amputation. However, little is known about the extent to which the original pathways retain residual function after peripheral amputation. Our earlier, acute study on long-term amputees indicated that central pathways associated with amputated peripheral nerves retain at least some sensory and motor function. The purpose of the present study was to determine if these functional connections would be strengthened or improved with experience and training over several days time. To do this, electrodes were implanted within fascicles of severed nerves of long-term human amputees to evaluate the changes in electrically evoked sensations and volitional motor neuron activity associated with attempted phantom limb movements. Nerve stimulation consistently resulted in discrete, unitary, graded sensations of touch/pressure and joint-position sense. There was no significant change in the values of stimulation parameters required to produce these sensations over time. Similarly, while the amputees were able to improve volitional control of motor neuron activity, the rate and pattern of change was similar to that seen with practice in normal individuals on motor tasks. We conclude that the central plasticity seen after amputation is most likely primarily due to unmasking, rather than replacement, of existing synaptic connections. These results also have implications for neural control of prosthetic limbs.