INCREASE IN PURKINJE-CELL GAIN ASSOCIATED WITH NATURALLY ACTIVATED CLIMBING FIBER INPUT
INCREASE IN PURKINJE-CELL GAIN ASSOCIATED WITH NATURALLY ACTIVATED CLIMBING FIBER INPUT
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DOI：
10.1152/jn.1983.50.1.205
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发表时间：
1983-01-01
影响因子：
2.5
通讯作者：
BLOEDEL, JR
中科院分区：
文献类型：
--
作者：
EBNER, TJ;YU, QX;BLOEDEL, JR
这些实验的目的是测试这一假设，即由外周刺激引起的攀爬纤维输入增加浦肯野细胞对苔藓纤维输入的反应性。这一假设是基于以前的一系列观察表明，自发攀爬纤维的输入与浦肯野细胞的反应，随后苔藓纤维输入的加重。此外，攀爬纤维和苔藓纤维输入之间的短期非持续性相互作用一直是许多小脑功能理论的重要方面。从去大脑、未麻醉猫的小叶V中的浦肯野细胞进行细胞外单位记录。为了激活苔藓纤维和攀爬纤维的输入，前爪被动地由Ling振动器系统弯曲。根据刺激物激活的复杂尖峰的存在与否，开发了一种数据分析，将简单尖峰试验分为2组。在这些试验中，复杂的尖峰被激活，简单的尖峰列车对齐的复杂尖峰的发生。对于前爪输入的每个简单尖峰响应，将响应期间的平均放电率与那些激活复杂尖峰的试验和那些未激活复杂尖峰的试验中的背景进行比较。从这两组试验中构建的直方图中的响应幅度的比率允许量化的响应性变化时，攀爬纤维输入被激活。结果表明，兴奋性和抑制性的简单锋电位反应都与复合锋电位的激活有关。使用任意水平的增益变化率为120%作为指示显著修改，当存在爬升光纤输入时，分析的64%的响应分量的幅度增加。简单的尖峰响应组件之前发生的复杂的尖峰激活通常不加重，虽然在少数细胞的响应的这一组成部分的幅度增加。此外，在少数细胞中，复杂锋电位的发生与一个新的简单锋电位成分有关。对于兴奋性反应，增益变化率的大小被证明是负相关的苔藓纤维输入诱发的简单的尖峰响应的幅度。所获得的数据是一致的假设，即攀缘纤维输入与浦肯野细胞苔藓纤维输入的反应性增加。无论外周刺激诱发的简单锋电位调制是兴奋性还是抑制性，反应性都会增加。反应性的变化是短期的和非持久的。有人认为，向小脑皮质的攀爬纤维输入的激活与浦肯野细胞对自然外周刺激激活的苔藓纤维输入的增加有关。
These experiments were designed to test the hypothesis that climbing fiber inputs evoked by a peripheral stimulus increase the responsiveness of Purkinje cells to mossy fiber inputs. This hypothesis was based on a previous series of observations demonstrating that spontaneous climbing fiber inputs are associated with an accentuation of the Purkinje cell responses to subsequent mossy fiber inputs. Furthermore, short-term nonpersistent interactions between climbing and mossy fiber inputs have been an important aspect of many theories of cerebellar function. Extracellular unitary recordings were made from Purkinje cells in lobule V of decerebrate, unanesthetized cats. To activate mossy and climbing fiber inputs, the forepaw was passively flexed by a Ling vibrator system. A data analysis was developed to sort the simple spike trials into 2 groups, based on the presence or absence of complex spikes activated by the stimulus. During those trials in which complex spikes were activated, the simple spike train was aligned on the occurrence of the complex spike. For each simple spike response to the forepaw input, the average firing rate during the response was compared to background both in those trials in which complex spikes were activated and in those in which they were not. The ratio of the response amplitudes in the histograms constructed from these two groups of trials permitted a quantification of the change in responsiveness when climbing fiber inputs were activated. The results show that both excitatory and inhibitory simple spike responses are accentuated when associated with the activation of a complex spike. Using an arbitrary level of a gain change ratio of 120% as indicating a significant modification, 64% of the response components analyzed increased their amplitude when climbing fiber input was present. Simple spike response components occurring prior to complex spike activation were usually not accentuated, although in a few cells the amplitude of this component of the response increased. In addition, in a small number of cells the occurrence of complex spikes was associated with a new simple spike component. For excitatory responses, the magnitude of the gain change ratio was shown to be inversely related to the amplitude of the simple spike response evoked by the mossy fiber inputs. The data obtained are consistent with the hypothesis that the climbing fiber input is associated with an increase in the responsiveness of Purkinje cells to mossy fiber inputs. The increased responsiveness occurs whether the simple spike modulation evoked by the peripheral stimulus is excitatory or inhibitory. The change in responsiveness is short-term and nonpersistent. It is argued that the activation of climbing fiber inputs to the cerebellar cortex is associated with an increase in the gain of Purkinje cells to mossy fiber inputs activated by natural peripheral stimuli.