Mechanism of climbing fiber synapse elimination at the developing Purkinje cell bodies

在发育中的小脑中，攀缘纤维（CF）-浦肯野细胞（PC）突触从PC细胞体中消除，而抑制性中间神经元如篮（BC）或Lugaro细胞（LC）的成熟继续进行。目前还不清楚这些兴奋性和抑制性输入是否直接相关。在本研究中，我们研究了当抑制性中间神经元功能被破坏时，CF-PC突触从PC细胞体中消除的过程。通过使用慢病毒和GFP表达报告小鼠的分析，我们发现体细胞CF终末被发育中的BC轴突排出。与PC胞体相反，在出生后第二周，PC层下的CF终末数量增加，来自多个神经元来源的CF被发现支配单个LC的体树突结构域。因此，体细胞CFs的消除似乎与抑制性神经元元件的分化一起进行。

In the developing cerebellum, climbing fiber (CF)-Purkinje cell (PC) synapses are eliminated from PC cell bodies, while the maturation of inhibitory interneurons such as basket (BC) or Lugaro cells (LC) proceeds. It has been unclear whether these excitatory and inhibitory inputs are directly correlated or not. In the present study, we investigated the process of CF-PC synapses elimination from PC cell bodies when the inhibitory interneurons are functionally disrupted. By analyses using with lentivirus and GFP-expressing reporter mouse, we found that somatic CF terminals were expelled by developing BC axons. In contrast to PC somata, CF terminals beneath PC layer increased in number during the second postnatal week, and CFs from multiple neuronal origins were found to innervate the somatodendritic domain of single LCs. Thus, the elimination of somatic CFs appears to proceed with the differentiation of inhibitory neuronal elements.