Ablation of cerebellar nuclei prevents H-reflex down-conditioning in rats
Ablation of cerebellar nuclei prevents H-reflex down-conditioning in rats
复制标题
DOI：
10.1101/lm.91305
复制
发表时间：
2005-05-01
影响因子：
2
通讯作者：
Wolpaw, JR
中科院分区：
文献类型：
--
作者：
Chen, XY;Wolpaw, JR
虽然小脑参与学习和记忆的研究已经描述了小脑内的可塑性，但其在CNS其他部位获得可塑性的作用在很大程度上尚未探索。本研究旨在确定是否需要小脑来获得脊髓可塑性，脊髓可塑性是H反射（脊髓牵张反射的电模拟物）操作性条件性降低的基础。大鼠小脑输出核齿状核和间位核（DIN）已被消融，暴露50天的H-反射下调节协议。DIN消融本身对H反射大小没有显著的长期影响，完全阻止了较小H反射的获得。由于先前的研究表明，皮质脊髓束（CST）横断也防止下条件反射，而红核脊髓束和其他主要下行束的横断没有，这一结果意味着DIN输出，影响皮质是必不可少的产生的CST活动，诱导脊髓可塑性，这是，反过来，直接负责较小的H反射。这一结果扩展了小脑在学习和记忆中的作用，包括参与中枢神经系统其他部位的可塑性诱导，特别是脊髓。小脑可能只是支持感觉运动皮层或其他地方改变脊髓的过程，或者小脑本身可能经历类似于前庭眼反射（VOR）或眨眼条件反射的可塑性。
While studies of cerebellar involvement in learning and memory have described plasticity within the cerebellum, its role in acquisition of plasticity elsewhere in the CNS is largely unexplored. This study set out to determine whether the cerebellum is needed for acquisition of the spinal cord plasticity that underlies operantly conditioned decrease in the H-reflex, the electrical analog of the spinal stretch reflex. Rats in which the cerebellar output nuclei dentate and interpositus (DIN) had been ablated were exposed for 50 d to the H-reflex down-conditioning protocol. DIN ablation, which in itself had no significant long-term effect on H-reflex size, entirely prevented acquisition of a smaller H-reflex. Since previous studies show that corticospinal tract (CST) transection also prevents down-conditioning while transection of the rubrospinal tract and other major descending tracts does not, this result implies that DIN output that affects cortex is essential for generation of the CST activity that induces the spinal cord plasticity, which is, in turn, directly responsible for the smaller H-reflex. The result extends the role of the cerebellum in learning and memory to include participation in induction of plasticity elsewhere in the CNS, specifically in the spinal cord. The cerebellum might simply support processes in sensorimotor cortex or elsewhere that change the spinal cord, or the cerebellum itself might undergo plasticity similar to that Occurring with vestibulo-ocular reflex (VOR) or eyeblink conditioning.