The cerebellum in maintenance of a motor skill: a hierarchy of brain and spinal cord plasticity underlies H-reflex conditioning.
The cerebellum in maintenance of a motor skill: a hierarchy of brain and spinal cord plasticity underlies H-reflex conditioning.
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小脑维持运动技能：大脑和脊髓可塑性的层次结构是 H 反射调节的基础。
DOI：
10.1101/lm.92706
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
Chen,XiangYang
中科院分区：
文献类型：
--
作者：
Wolpaw,JonathanR;Chen,XiangYang
H 反射的操作性条件反射（脊髓牵张反射的电模拟）是技能习得的简单模型，涉及脊髓的可塑性。之前的研究表明，小脑对于下调 H 反射至关重要。这项研究询问小脑是否对于维持下调也很重要。大鼠响应下调方案而降低比目鱼肌 H 反射超过 50 天后，小脑齿状输出核和间质核 (DIN) 被消融，下调条件持续 50-100 天。在幼稚（即未条件反射）大鼠中，DIN 消融本身对 H 反射大小没有显着的长期影响。在 DIN 消融之前的下调过程中，8 只 Sprague-Dawley 大鼠的 H 反射降低至对照的 57% (±4 SEM)。消融后它上升，在 2 天内稳定在 75% 左右，并保持在消融后约 40 天。然后它上升到~130%，在消融后 100 天研究结束时一直保持在这个水平。因此，在下调状态的大鼠中，DIN 消融引起 H 反射的立即增加和延迟增加。最终结果是 H 反射明显大于下调条件之前的水平。结合之前的工作，这些显着的结果表明，直接负责下调的脊髓可塑性（其本身仅存活 5-10 天）是由脊髓上可塑性维持的，在小脑输出丧失后，脊髓可塑性可存活约 40 天。因此，H 反射调节似乎取决于大脑和脊髓可塑性的层次结构，小脑对此做出了重要贡献。
Operant conditioning of the H-reflex, the electrical analog of the spinal stretch reflex, is a simple model of skill acquisition and involves plasticity in the spinal cord. Previous work showed that the cerebellum is essential for down-conditioning the H-reflex. This study asks whether the cerebellum is also essential for maintaining down-conditioning. After rats decreased the soleus H-reflex over 50 d in response to the down-conditioning protocol, the cerebellar output nuclei dentate and interpositus (DIN) were ablated, and down-conditioning continued for 50–100 more days. In naive (i.e., unconditioned) rats, DIN ablation itself has no significant long-term effect on H-reflex size. During down-conditioning prior to DIN ablation, eight Sprague-Dawley rats decreased the H-reflex to 57% (±4 SEM) of control. It rose after ablation, stabilizing within 2 d at about 75% and remaining there until ∼40 d after ablation. It then rose to ∼130%, where it remained through the end of study 100 d after ablation. Thus, DIN ablation in down-conditioned rats caused an immediate increase and a delayed increase in the H-reflex. The final result was an H-reflex significantly larger than that prior to down-conditioning. Combined with previous work, these remarkable results suggest that the spinal cord plasticity directly responsible for down-conditioning, which survives only 5–10 d on its own, is maintained by supraspinal plasticity that survives ∼40 d after loss of cerebellar output. Thus, H-reflex conditioning seems to depend on a hierarchy of brain and spinal cord plasticity to which the cerebellum makes an essential contribution.