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摘要 : 浦肯野细胞是小脑中的抑制性神经元,在协调身体运动功能中起中心作用。人们长期认为它们编码“扫视”这种眼睛快速运动方式,但这一点是怎么做到的过去却不知道。

 浦肯野细胞是小脑中的抑制性神经元,在协调身体运动功能中起中心作用。人们长期认为它们编码“扫视”这种眼睛快速运动方式,但这一点是怎么做到的过去却不知道。现在,通过记录来自猴子浦肯野细胞的信号,David Herzfeld等人发现,将爆发的和暂停的浦肯野细胞的简单峰值反应结合起来,可以预测 “扫视”的实时速度,但其中任何一个细胞类群都无法单独进行这种预测。而且,当浦肯野细胞按它们的复杂峰值场(complex-spike field)来组织时,这些细胞的反应会通过一个增益场(gain field)来既编码速度、又编码方向。


Encoding of action by the Purkinje cells of the cerebellum


Execution of accurate eye movements depends critically on the cerebellum, suggesting that the major output neurons of the cerebellum, Purkinje cells, may predict motion of the eye. However, this encoding of action for rapid eye movements (saccades) has remained unclear: Purkinje cells show little consistent modulation with respect to saccade amplitude or direction, and critically, their discharge lasts longer than the duration of a saccade. Here we analysed Purkinje-cell discharge in the oculomotor vermis of behaving rhesus monkeys (Macaca mulatta) and found neurons that increased or decreased their activity during saccades. We estimated the combined effect of these two populations via their projections to the caudal fastigial nucleus, and uncovered a simple-spike population response that precisely predicted the real-time motion of the eye. When we organized the Purkinje cells according to each cell’s complex-spike directional tuning, the simple-spike population response predicted both the real-time speed and direction of saccade multiplicatively via a gain field. This suggests that the cerebellum predicts the real-time motion of the eye during saccades via the combined inputs of Purkinje cells onto individual nucleus neurons. A gain-field encoding of simple spikes emerges if the Purkinje cells that project onto a nucleus neuron are not selected at random but share a common complex-spike property.

来源: Nature 浏览次数:0


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