Synaptic action of the olivocerebellar system on cerebellar nuclear spike activity.
Synaptic action of the olivocerebellar system on cerebellar nuclear spike activity.
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DOI：
10.1523/jneurosci.3323-11.2011
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发表时间：
2011-10-12
期刊：
影响因子：
--
通讯作者：
Lang EJ
中科院分区：
文献类型：
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作者：
Blenkinsop TA;Lang EJ
小脑输出是许多神经系统功能，特别是运动协调的理想实现所必需的。要理解这种输出的产生，关键的一步是确定影响小脑核团(CN)活动的因素。调节CN活动的突触输入有四个主要来源；爬行纤维和苔藓纤维的侧枝有两个，其余两个由浦肯野细胞(PC)轴突以简单棘波(SSS)和复杂棘波(CS)的形式提供。大多数关于小脑功能的假说都将SSS作为CN活动的主要决定因素。然而，很可能css也会对CN活动产生显著的直接影响，这一点很少被考虑到。为了探索这种可能性，我们记录了大鼠突触连接的PC-CN神经元细胞对。这类记录的CS和CN活动的交叉记录表明，自发的CS对CN活动有很强的抑制作用，在某些情况下显然足以引发CN神经元内在兴奋性的变化，这种变化持续时间长于CS介导的GABA能IPSP。此外，许多CS-CN相关图显示了最初的兴奋反应，证明了攀升纤维侧支显著兴奋CN神经元的能力。相当一部分(24%)的相关图显示了兴奋-抑制序列，这提供了证据，证明CN神经元经常接受来自与支配投射到它的PC相同的橄榄小脑轴突的侧支。因此，兴奋后抑制似乎是许多CN神经元对橄榄球小脑活动的一种硬连接反应模式。
Cerebellar output is necessary for the ideal implementation of many nervous system functions, particularly motor coordination. A key step toward understanding the generation of this output is characterizing the factors that shape the activity of the cerebellar nuclei (CN). There are four major sources of synaptic input that modulate CN activity; collaterals of climbing and mossy fibers are two, and the remaining two are provided by Purkinje cell (PC) axons in the form of simple spikes (SSs) and complex spikes (CSs). Most hypotheses of cerebellar function focus on SSs as the primary determinant of CN activity. However, it is likely that CSs also cause significant direct effects on CN activity, something that is rarely considered. To explore this possibility we recorded from synaptically-connected PC-CN neuron cell pairs in rats. Crosscorrelograms of CS and CN activity from such recordings demonstrate that spontaneous CSs have a strong inhibitory effect on CN activity, apparently sufficient in some cases to trigger changes in the intrinsic excitability of the CN neuron that long outlast the underlying CS-mediated GABAergic IPSP. Furthermore, many CS-CN correlograms show an initial excitatory response, demonstrating the ability of climbing fiber collaterals to significantly excite CN neurons. A substantial fraction (24%) of correlograms displayed an excitation-inhibition sequence, providing evidence that a CN neuron often receives collaterals from the same olivocerebellar axons as innervate the PCs projecting to it. Thus, excitation followed by inhibition appears to be a hard-wired response pattern of many CN neurons to olivocerebellar activity.