Caminiti R, Sbriccoli A
J Comp Neurol. 1985 Jul 1;237(1):85-99. doi: 10.1002/cne.902370107.
The callosal connections of the superior parietal lobule, area 5 of Brodmann, were studied in macaque monkeys (M. nemestrina and M. fascicularis) using anatomical techniques based on both anterograde and retrograde axoplasmic transport of wheat-germ-agglutinin-conjugated horseradish peroxidase. From sagittal sections, two-dimensional flattened computer reconstructions of the volumes of cortical tissue containing callosal-projecting neurons (callosal efferent zone) and/or callosal terminal axons (callosal terminal territory) were obtained. Callosal zones were found in area 5, including the supplementary sensory area, in a limited part of area 6, i.e., in the supplementary motor area, in area 7b, in the cortex of the dorsal bank of the sylvian fissure, and in a limited part of area 7a, in the cortex of the upper third of the rostral bank of the superior temporal sulcus. Callosal neurons in all cortical areas studied, though with regional variations, predominated in layer IIIb, but were also very numerous in layers VI and V. They were rare in other cortical laminae. In the cortical regions projecting heterotopically to area 5, the tangential distribution of callosal neurons was discontinuous because of the presence of large acallosal regions. These were not observed in area 5, although here the distribution of callosal neurons waxed and waned in the tangential cortical plane. Callosal axons to and/or from area 5 crossed the midline in the posterior, presplenial part of the corpus callosum. In the superior parietal lobule they terminated in radial patches or columns, spanning layers I-IV. These columns of various width (200-2,000 micron) were separated by gaps of similar size, free of such terminals. Callosal neurons were present not only within, but also between, the callosal terminal columns. Callosal neurons located within the callosal terminal columns were, in a statistically significant way, more numerous than those located between them. The callosal efferent zone occupied 71% of the tangential domain of area 5, whereas the callosal terminal territory occupied only 49% of it. This difference is statistically significant. The discontinuous columnar arrangement of callosal terminals and the periodic distribution of callosal neurons in the lateral part of area 5 defined three main bands of callosal connections of irregular shape which were oriented mediolaterally and ran parallel to the main architectonic borders, the border between areas 2 and 5 and that between 5 and 7.
采用基于小麦胚芽凝集素结合辣根过氧化物酶顺行和逆行轴浆运输的解剖学技术，在猕猴（猪尾猕猴和束状猕猴）中研究了顶上小叶（布罗德曼第5区）的胼胝体连接。从矢状切片中，获得了包含胼胝体投射神经元（胼胝体传出区）和/或胼胝体终末轴突（胼胝体终末区）的皮质组织体积的二维平面计算机重建图。在第5区发现了胼胝体区，包括辅助感觉区，在第6区的有限部分，即辅助运动区，在第7b区，在外侧裂背侧皮质，以及在第7a区的有限部分，在上颞沟嘴侧缘上三分之一的皮质。在所研究的所有皮质区域中，胼胝体神经元虽然存在区域差异，但在IIIb层中占主导地位，但在VI层和V层中也非常多。它们在其他皮质层中很少见。在异位投射到第5区的皮质区域中，由于存在大的无胼胝体区域，胼胝体神经元的切向分布是不连续的。在第5区未观察到这些区域，尽管在这里胼胝体神经元的分布在切向皮质平面上有增减。到第5区和/或来自第5区的胼胝体轴突在胼胝体的后部、胼胝体前部分交叉中线。在顶上小叶中，它们终止于放射状斑块或柱中，跨越I-IV层。这些不同宽度（200-2000微米）的柱被大小相似的间隙隔开，间隙中没有这种终末。胼胝体神经元不仅存在于胼胝体终末柱内，也存在于它们之间。位于胼胝体终末柱内的胼胝体神经元在统计学上比位于它们之间的胼胝体神经元更多。胼胝体传出区占第5区切向区域的71%，而胼胝体终末区仅占其49%。这种差异具有统计学意义。胼胝体终末的不连续柱状排列以及第5区外侧部分胼胝体神经元的周期性分布定义了三个主要的不规则形状的胼胝体连接带，它们呈内外侧方向排列，与主要的构筑边界平行，即第2区和第5区之间以及第5区和第7区之间的边界。
