Non-uniform olivocerebellar conduction time in the vermis of the rat cerebellum
Non-uniform olivocerebellar conduction time in the vermis of the rat cerebellum
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DOI：
10.1113/jphysiol.2005.099176
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发表时间：
2006-02-01
影响因子：
5.5
通讯作者：
Edgley, SA
中科院分区：
文献类型：
--
作者：
Baker, MR;Edgley, SA
有人提出，小脑攀爬纤维（橄榄小脑）轴突的传导速度根据长度进行调整，以精确固定下橄榄和小脑皮层之间的传导时间。有些数据与这个观点相冲突。我们使用攀爬纤维反射重新评估了这个问题。在小叶 VI 或 VII 中的一片叶子尖端的白质在表面以下 0.5-1 mm 处受到电刺激，并由小叶 VIII 和 IX 中的浦肯野细胞进行记录。在皮层狭窄矢状区发现的浦肯野细胞的不同深度记录了反射诱发的攀爬纤维（CF）反应（33个单位），作为复杂的尖峰。响应的延迟范围为 4.3 毫秒到 11.3 毫秒。一致的趋势是，在个体实验和分组数据中，在更深度记录的浦肯野细胞反应比更浅层记录的浦肯野细胞反应具有更短的 CF 反射潜伏期。这些数据表明，CF 反射潜伏期不是恒定的，而是与动作电位沿 CF 传播的距离成正比。这些数据与调整 CF 传导速度以使橄榄小脑传导时间正常化不一致，但与皮质中约 0.6 m s(-1) 的 CF 传导速度一致。这表明投射到小脑皮层不同部分的攀爬纤维可能在尖峰传导时间上存在几毫秒的差异，并且亚毫秒精度并不是攀爬纤维信号的重要因素。
It has been proposed that the conduction velocities of cerebellar climbing fibre (olivocerebellar) axons are tuned according to length, in order to precisely fix the conduction time between the inferior olive and cerebellar cortex. Some data conflict with this view. We have re-evaluated this issue using the climbing fibre reflex. The white matter of the tip of one folium in lobule VI or VII was stimulated electrically 0.5-1 mm below the surface and recordings were made from Purkinje cells in lobules VIII and IX. Reflex evoked climbing fibre (CF) responses (33 units) were recorded at different depths from Purkinje cells found in a narrow sagittal zone of cortex as complex spikes. The responses had latencies ranging from 4.3 ms to 11.3 ms. A consistent trend was that Purkinje cell responses recorded at greater depth had shorter CF reflex latencies than those recorded more superficially, both in individual experiments and in grouped data. These data show that the CF reflex latency is not constant, but is directly proportional to the distance an action potential has to travel along a CF. These data are not consistent with tuning of CF conduction velocities to normalize olivocerebellar conduction time, but are consistent with a CF conduction velocity in the cortex of approximately 0.6 m s(-1). This suggests that climbing fibres projecting to different parts of the cerebellar cortex may have differences in spike conduction time of a few milliseconds, and that submillisecond precision is not an important element of the climbing fibre signal.