Developmental Rewiring between Cerebellar Climbing Fibers and Purkinje Cells Begins with Positive Feedback Synapse Addition
Developmental Rewiring between Cerebellar Climbing Fibers and Purkinje Cells Begins with Positive Feedback Synapse Addition
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DOI：
10.1016/j.celrep.2019.10.081
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发表时间：
2019-11-26
期刊：
影响因子：
8.8
通讯作者：
Lichtman, Jeff William
中科院分区：
文献类型：
--
作者：
Wilson, Alyssa Michelle;Schalek, Richard;Lichtman, Jeff William
在出生后发育过程中，小脑攀爬纤维将其神经支配强度改变到多余的浦肯野细胞目标上，从而在成年期产生一对数的连接模式。为了深入了解负责这种重新映射的过程，我们重建了小鼠出生后第一周的连续电子显微镜数据集。在第 3 天到第 7 天之间，单个攀爬纤维以正反馈方式选择性地将许多突触添加到浦肯野目标的子集上，而不从其他目标中修剪突触。与强输入和弱输入相关的突触活动区域大小是无法区分的。因此，突触数量的变化是早期发育可塑性的主要形式。最后，局部区域的攀爬纤维和浦肯野细胞的数量几乎匹配。因此，最初通过攀爬纤维对浦肯野细胞进行过度神经支配是经济的：进入一个区域的轴突数量足以确保每个轴突最终保留一个突触后目标，并且没有一个轴突在那里徒劳地分支。
During postnatal development, cerebellar climbing fibers alter their innervation strengths onto supernumerary Purkinje cell targets, generating a one-to-few connectivity pattern in adulthood. To get insight about the processes responsible for this remapping, we reconstructed serial electron microscopy data-sets from mice during the first postnatal week. Between days 3 and 7, individual climbing fibers selectively add many synapses onto a subset of Purkinje targets in a positive-feedback manner, without pruning synapses from other targets. Active zone sizes of synapses associated with powerful versus weak inputs are indistinguishable. Changes in synapse number are thus the predominant form of early developmental plasticity. Finally, the numbers of climbing fibers and Purkinje cells in a local region nearly match. Initial over-innervation of Purkinje cells by climbing fibers is therefore economical: the number of axons entering a region is enough to assure that each ultimately retains a postsynaptic target and that none branched there in vain.