Institute of Computational Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
Department of Neuroscience, Karolinska Institute, Stockholm, Sweden.
J Comp Neurol. 2019 Jun 1;527(8):1315-1332. doi: 10.1002/cne.24630. Epub 2019 Jan 22.
The present study describes the ipsilateral and contralateral cortico-cortical and cortico-thalamic connectivity of the parietal visual areas, posterior parietal caudal cortical area (PPc) and posterior parietal rostral cortical area (PPr), in the ferret using standard anatomical tract-tracing methods. The two divisions of posterior parietal cortex of the ferret are strongly interconnected, however area PPc shows stronger connectivity with the occipital and suprasylvian visual cortex, while area PPr shows stronger connectivity with the somatomotor cortex, reflecting the functional specificity of these two areas. This pattern of connectivity is mirrored in the contralateral callosal connections. In addition, PPc and PPr are connected with the visual and somatomotor nuclei of the dorsal thalamus. Numerous connectional similarities exist between the posterior parietal cortex of the ferret (PPc and PPr) and the cat (area 7 and 5), indicative of the homology of these areas within the Carnivora. These findings highlight the existence of a frontoparietal network as a shared feature of the organization of parietal cortex across Euarchontoglires and Laurasiatherians, with the degree of expression varying in relation to the expansion and areal complexity of the posterior parietal cortex. This observation indicates that the ferret is a potentially valuable experimental model animal for understanding the evolution and function of the posterior parietal cortex and the frontoparietal network across mammals. The data generated will also contribute to a connectomics database, to further cross-species analyses of connectomes and illuminate wiring principles of cortical connectivity across mammals.
本研究采用标准解剖学示踪方法描述了雪貂顶叶视觉区、后顶叶尾侧皮质区（PPc）和后顶叶吻侧皮质区（PPr）的同侧和对侧皮质-皮质及皮质-丘脑连接。雪貂的两个顶叶后部分区强烈相互连接，但区 PPc 与枕叶和上外侧视觉皮层的连接更强，而区 PPr 与躯体运动皮层的连接更强，反映了这两个区域的功能特异性。这种连接模式在对侧胼胝体连接中得到了反映。此外，PPc 和 PPr 与背侧丘脑的视觉和躯体运动核相连。雪貂（PPc 和 PPr）和猫（区域 7 和 5）的后顶叶皮层之间存在许多相似的连接，表明这些区域在食肉目中具有同源性。这些发现强调了顶叶网络的存在，它是欧亚大陆真兽类和劳亚兽类顶叶皮层组织的共同特征，其表达程度与后顶叶皮层的扩展和区域复杂性有关。这一观察表明，雪貂是一种潜在有价值的实验模型动物，可用于理解后顶叶皮层和额顶叶网络在哺乳动物中的进化和功能。生成的数据也将有助于建立一个连接组学数据库，进一步进行跨物种的连接组学分析，并阐明哺乳动物皮质连接的布线原则。
