The most prominent transient compartment of the primate fetal cortex is the deep, cell-sparse, synapse-containing subplate compartment (SPC). The developmental role of the SPC and its extraordinary size in humans remain enigmatic.

This paper evaluates evidence on the development and connectivity of the SPC and discusses its role in the pathogenesis of neurodevelopmental disorders. A synthesis of data shows that the subplate becomes a prominent compartment by its expansion from the deep cortical plate (CP), appearing well-delineated on MR scans and forming a tangential nexus across the hemisphere, consisting of an extracellular matrix, randomly distributed postmigratory neurons, multiple branches of thalamic and long corticocortical axons. The SPC generates early spontaneous non-synaptic and synaptic activity and mediates cortical response upon thalamic stimulation. The subplate nexus provides large-scale interareal connectivity possibly underlying fMR resting-state activity, before corticocortical pathways are established. In late fetal phase, when synapses appear within the CP, transient the SPC coexists with permanent circuitry. The histogenetic role of the SPC is to provide interactive milieu and capacity for guidance, sorting, “waiting” and target selection of thalamocortical and corticocortical pathways. The new evolutionary role of the SPC and its remnant white matter neurons is linked to the increasing number of associative pathways in the human neocortex. These roles attributed to the SPC are regulated using a spatiotemporal gene expression during critical periods, when pathogenic factors may disturb vulnerable circuitry of the SPC, causing neurodevelopmental cognitive circuitry disorders.

灵长类胎儿皮层最突出的瞬时隔室是深的、细胞稀疏的、含有突触的亚板隔室 (SPC)。SPC 的发育作用及其在人类中的非凡大小仍然是个谜。

本文评估了 SPC 发育和连通性的证据，并讨论了其在神经发育障碍发病机制中的作用。数据综合显示，亚板通过从深层皮质板 (CP) 扩展而成为一个突出的隔室，在 MR 扫描中显示清晰，并在整个半球形成切向连接，由细胞外基质、随机分布的迁移后神经元组成，丘脑和长皮质轴突的多个分支。SPC 产生早期自发的非突触和突触活动，并在丘脑刺激时介导皮质反应。在皮质皮质通路建立之前，亚板连接提供了大规模的区域间连接，可能是 fMR 静息状态活动的基础。在胎儿晚期，当突触出现在 CP 中时，瞬态 SPC 与永久电路共存。SPC 的组织发生作用是为丘脑皮质和皮质皮质通路的指导、分类、“等待”和目标选择提供交互环境和能力。SPC 及其残余白质神经元的新进化作用与人类新皮层中越来越多的关联通路有关。归因于 SPC 的这些作用在关键时期使用时空基因表达进行调节，此时致病因素可能会干扰 SPC 的脆弱回路，导致神经发育认知回路障碍。丘脑皮质和皮质皮质通路的“等待”和目标选择。SPC 及其残余白质神经元的新进化作用与人类新皮层中越来越多的关联通路有关。归因于 SPC 的这些作用在关键时期使用时空基因表达进行调节，此时致病因素可能会干扰 SPC 的脆弱回路，导致神经发育认知回路障碍。丘脑皮质和皮质皮质通路的“等待”和目标选择。SPC 及其残余白质神经元的新进化作用与人类新皮层中越来越多的关联通路有关。归因于 SPC 的这些作用在关键时期使用时空基因表达进行调节，此时致病因素可能会干扰 SPC 的脆弱回路，导致神经发育认知回路障碍。