Early specification of the hierarchical organization of visual cortical areas in the macaque monkey
Early specification of the hierarchical organization of visual cortical areas in the macaque monkey
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DOI：
10.1093/cercor/12.5.453
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发表时间：
2002-05-01
期刊：
影响因子：
3.7
通讯作者：
Kennedy, H
中科院分区：
文献类型：
--
作者：
Batardière, A;Barone, P;Kennedy, H
皮质-皮质投射神经元的层状组织（由颗粒上投射神经元SLN%的百分比表示）将皮质通路表征为前馈（FF）或反馈（FB），并确定皮质区域的分层排名。有证据表明，SLN%的通路到V1区的发育减少。在这里，通过分析出生前和出生后的预测V4区，我们已经能够解决是否发展减少SLN%的信息处理在未成熟的皮层的影响。到区域V4的FB途径显示SLN%减少28-84%。这与FF预测相反，FF预测显示SLN%减少很少或没有减少。然而，SLN%值在未成熟的皮质分配皮质区在成人相同的层次结构。SLN%的发育性降低是新皮层中的普遍现象，并且是FB通路的显著特征。两种机制有助于SLN%的发育变化：（i）延迟轴突从颗粒下层神经元长入皮质靶区和（ii）延长颗粒上层神经元投射发散的发育减少。目前的研究结果表明，FF和FB的预测表现出不同的发展过程和模式的连接皮质区和他们的层次关系建立产前，独立的回归现象。
The laminar organization of cortico-cortical projection neurons (expressed by the percentage of supragranular projecting neurons SLN%) characterizes cortical pathways as feedforward (FF) or feedback (FB) and determines the hierarchical ranking of cortical areas. There is evidence of a developmental reduction in SLN% of pathways to area V1. Here, by analyzing pre- and postnatal projections to area V4, we have been able to address whether developmental reductions of SLN% impact on information processing in the immature cortex. FB pathways to area V4 exhibit 28-84% reduction of SLN%. This contrasts with the FF projections, which show little or no SLN% reduction. However, SLN% values in the immature cortex allocated cortical areas to the same hierarchical levels as in the adult. The developmental reduction of SLN% is a widespread phenomenon in the neocortex and is a distinctive feature of FB pathways. Two mechanisms contribute to developmental changes in SLN%: (i) delayed ingrowth of axons into the cortical target from infragranular layer neurons and (ii) prolonged developmental reduction of the divergence of projections from supragranular layer neurons. The present results show that FF and FB projections exhibit different developmental processes and patterns of connections linking cortical areas and their hierarchical relations are established prenatally, independently of regressive phenomena.