Organization and remodeling of the olivocerebellar climbing fiber projection
Organization and remodeling of the olivocerebellar climbing fiber projection
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DOI：
10.1080/14734220500527385
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
I. Sugihara
中科院分区：
文献类型：
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作者：
I. Sugihara
攀爬纤维是下橄榄神经元轴突的终末部分，以排他性的一对一关系与浦肯野细胞形成强大的突触连接。这一投射是在发育过程中通过对每个攀缘纤维和整个轴突树枝的剧烈重塑而建立的。早期的攀援纤维形成松散的“爬行”型终枝，在出生后的第一周似乎与许多浦肯野细胞接触很弱。然后，顶杆集中在单个浦肯野细胞上，并聚集肿胀(过渡型)，最终在出生后第二周紧紧地包围浦肯野细胞胞体(巢型)。然后，顶枝向上移位到浦肯野细胞顶端树突的茎(‘卷须’或‘帽’)，最终到达树状树的近端(成熟的攀援纤维)。大鼠单轴突形态观察表明，爬行期大鼠的橄榄小脑轴突比成年大鼠更频繁地分支，且有更多的攀爬纤维。起源于轴突的攀爬纤维主要被组织成微区，就像成年人一样。伴随着爬行纤维的这种重塑，在爬行动物发育到巢阶段的过程中，每个橄榄小脑轴突的爬行纤维数量显著减少。由于巢后的额外缩回，成人的橄榄小脑轴突约有七个攀爬纤维。上述发育过程中的形态重塑和收缩可以与在大鼠和小鼠中观察到的攀升纤维-浦肯野细胞突触相互作用的变化密切地进行比较。在爬行期和巢期之间的末端茎中肿胀的产生和聚集与突触连接的成熟有关。在同一时期和随后时期攀升纤维的减少与消除过多的突触以建立一对一的连接有关。
Climbing fibers, terminal portions of the axons of inferior olive neurons, form strong synaptic connections to Purkinje cells in an exclusive one-to-one relationship. This projection is established during development by drastic reshaping in each climbing fiber and in overall axonal arborization. Early climbing fibers form loose ‘creeper’-type terminal arbors that seem to make weak contact with many Purkinje cells in the first postnatal week. The terminal arbor then becomes focused on a single Purkinje cell with the aggregation of swellings (‘transitional’ type), and eventually tightly surrounds the Purkinje cell soma (‘nest’ type) in the second postnatal week. The terminal arbor is then displaced upward to the stem of the apical dendrite of the Purkinje cell (‘capuchon’ or ‘hood’) and eventually to the proximal portion of the dendritic tree (mature climbing fiber). Single-axon morphology in rats has shown that olivocerebellar axons in the creeper stage branch more frequently and have many more climbing fibers than those in adults. The climbing fibers that originate from an axon are largely organized into microzones as in adults. Concomitant with this remodeling of climbing fibers, the number of climbing fibers per olivocerebellar axon is significantly decreased by the putative retraction of climbing fibers during development from the creeper to nest stage. Due to additional retraction after the nest stage, an olivocerebellar axon in an adult has about seven climbing fibers. The above morphological remodeling and retraction during development can be closely compared to the changes in climbing fiber-Purkinje cell synaptic interaction observed in rats and mice. Generation and aggregation of the swellings in the terminal arbor between the creeper and nest stages are correlated with maturation of the synaptic connection. The decrease in climbing fibers in the same and following periods is correlated with the elimination of overabundant synapses to establish one-to-one connections.