Le Marec N, Caston J, Lalonde R
Hôtel-Dieu Hospital, Neurology Service, University of Montreal, Quebec, Canada.
Exp Brain Res. 1997 Aug;116(1):131-8. doi: 10.1007/pl00005733.
The cerebellum plays a role in various sensorimotor learning tasks. The purpose of the present studies was to evaluate sensorimotor skills in a spontaneous mouse mutant with cerebellar cortical atrophy. Lurcher mutant mice, characterized by massive losses of cerebellar granule cells and Purkinje cells, were assessed on two static beams varying in width and on an accelerating rotorod. On the static beams, lurcher mutants were deficient in stable positioning while immobile. Contrary to normal mice, they retreated backwards involuntarily and clung off-balance to the side of the beams. However, lurcher mutants were not deficient in segment crossings, body turns, latencies before crossing the first segment, and time spent in motion. There was an improvement over days in static stable positioning on both beams. On the rotorod, although lurcher mutants fell sooner and were inferior to controls in maximal speed of rotation achieved, there was an improvement on both measures across days. Moreover, retention of this motor skill was normal. These results indicate that, although lurcher mutants are limited in their capacity to execute motor coordination tasks, postural sensorimotor learning is not abolished in the absence of cerebellar cortical output neurons.
小脑在各种感觉运动学习任务中发挥作用。本研究的目的是评估一种患有小脑皮质萎缩的自发突变小鼠的感觉运动技能。Lurcher突变小鼠的特征是小脑颗粒细胞和浦肯野细胞大量缺失，对其在两种宽度不同的静态横梁以及加速旋转杆上进行评估。在静态横梁上，Lurcher突变小鼠在静止时缺乏稳定的定位能力。与正常小鼠相反，它们会不由自主地向后退缩，并以不平衡的姿势紧贴在横梁一侧。然而，Lurcher突变小鼠在跨越节段、身体转动、跨越第一节段前的潜伏期以及运动时间方面并不存在缺陷。在两根横梁上，随着时间推移，静态稳定定位能力都有所提高。在旋转杆上，虽然Lurcher突变小鼠更快掉落，并且在达到的最大旋转速度方面不如对照组，但在这两项指标上随着时间推移都有改善。此外，这种运动技能的保持是正常的。这些结果表明，尽管Lurcher突变小鼠执行运动协调任务的能力有限，但在没有小脑皮质输出神经元的情况下，姿势感觉运动学习并未被消除。
