Hierarchical organization of macaque and cat cortical sensory systems explored with a novel network processor
Hierarchical organization of macaque and cat cortical sensory systems explored with a novel network processor
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DOI：
10.1098/rstb.2000.0550
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发表时间：
2000-01-29
影响因子：
6.3
通讯作者：
Young, MP
中科院分区：
文献类型：
--
作者：
Hilgetag, CC;O'Neill, MA;Young, MP
神经解剖学家已经描述了猴子和猫皮质感觉系统的各种结构之间的大量联系。由于连接数据的复杂性，需要进行分析以了解它们所隐含的组织原则。到目前为止，分析椎板起源和融合连接数据以揭示皮质区域之间的等级关系一直是最被广泛认可的方法。我们编写了一个网络处理器，在给定已知的层次约束和解释规则的情况下，搜索皮质区域的最优层次排序。对于所有的皮质系统和所有的成本函数，处理器找到了大量同样低成本的层次结构。因此，目前在解剖学文献中可用的层状层级约束不足以约束我们所分析的任何感觉系统的唯一顺序。猴子视觉系统的等级排序已被广泛报道，但这些排序是手工得出的，并不在最佳排序之列。我们研究的所有皮质系统都表现出显著的层级组织，在最优层级中，猴子视觉和躯体运动系统的解剖约束得到满足，几乎没有违反约束的情况。因此，这种动物的视觉和躯体-运动系统具有令人惊讶的严格等级制度。在视觉系统的最佳结构中，约束和等级关系之间的大多数不一致与FST区(颞上沟底)的连接有关。他们发现，通过假设FST由两个不同预测性质的区域组成，分层解决方案可以进一步改进。事实上，我们发现在两个合理的条件下，在不违反任何解剖学约束的情况下，可以获得灵长类视觉系统的完美分层安排，即将FST细分为两个不同的区域，我们预测其连通性，以及取消至少一个不太可靠的规则约束。我们的分析表明，未来收集相同类型的层状约束，或者包括来自丘脑皮质连接的新的分层约束，Mill不能解决灵长类视觉系统的多个最优分层表征的问题。然而，进一步的数据可能有助于确定一些更多地区的相对顺序。这种视觉层次结构的不确定性部分是由于报告的大脑皮层区域之间缺乏某些联系。这些缺失与系统中不同处理流之间的有限串扰是一致的。因此，视觉系统的分层表示受其他组织特征的影响，并且必须考虑到这些特征。例如处理流。
Neuroanatomists have described a large number of connections between the various structures of monkey and cat cortical sensory systems. Because of the complexity of the connection data, analysis is required to unravel what principles of organization they imply. To date, analysis of laminar origin and termation connection data to reveal hierarchical relationships between the cortical areas has been the most widely acknowledged approach. We programmed a network processor that searches for optimal hierarchical orderings of cortical areas given known hierarchical constraints and rules for their interpretation.For all cortical systems and all cost functions, the processor found a multitude of equally low-cost hierarchies. Laminar hierarchical constraints that are presently available in the anatomical literature were therefore insufficient to constrain a unique ordering for any of the sensory systems we analysed. Hierarchical orderings of the monkey visual system that have been widely reported, but which were derived by hand, were not among the optimal orderings. All the cortical systems we studied displayed a significant degree of hierarchical organization, and the anatomical constraints from the monkey visual and somatomotor systems were satisfied with very few constraint violations in the optimal hierarchies. The visual and somato-motor systems in that animal were therefore surprisingly strictly hierarchical. Most inconsistencies between the constraints and the hierarchical relationships in the optimal structures for the visual system were related to connections of area FST (fundus of superior temporal sulcus). The found that the hierarchical solutions could be further improved by assuming that FST consists of two areas, which differ in the nature of their projections. Indeed, we found that perfect hierarchical arrangements of the primate visual system, without any violation of anatomical constraints, could be obtained under two reasonable conditions, namely the subdivision of FST into two distinct areas, whose connectivity we predict, and the abolition of at least one of the less reliable rule constraints.Our analyses showed that the future collection of the same type of laminar constraints, or the inclusion of new hierarchical constraints from thalamocortical connections, Mill not resolve the problem of multiple optimal hierarchical representations for the primate visual system. Further data, however, may help to specify the relative ordering of some more areas. This indeterminacy of the visual hierarchy is in part due to the reported absence of some connections between cortical areas. These absences are consistent with limited cross-talk between differentiated processing streams in the system. Hence, hierarchical representation of the visual system is affected by, and must take into account, other organizational features. such as processing streams.