Fujita I, Fujita T
Precursory Research for Embryonic Science and Technology (PRESTO), Research Development Corporation of Japan, Japan.
J Comp Neurol. 1996 May 13;368(4):467-86. doi: 10.1002/(SICI)1096-9861(19960513)368:4<467::AID-CNE1>3.0.CO;2-2.
Intrinsic connections in the inferior temporal cortex were analyzed by making extracellular injections of biocytin in Japanese macaques. Analysis was focused mainly on the dorsal part of area TE, in which a functional columnar organization has been shown. Interlaminar connections were analyzed in coronal section after laminar-specific microinjections, and intralaminar connections were examined from tangential sections. After injections at various depths in the dorsal TE, both axons and cell bodies were strongly labeled above or below the injection site in a columnar appearance. Axons from layer 3 ran in bundles towards the white matter and gave off prominent collaterals in layer 5. Ascending axons from lower to upper layers were also present (e.g., layers 4, 5, and 6 to layer 3). In tangential sections, there were abundant axons running parallel to the pia mater. These horizontal axons, particularly those in layers 2 and 3, produced patches of terminals 0.5 +/- 0.1 mm (mean +/- s.d.) in size and cylindrical in shape, spanning layers 1-3 or even to layers 4 and 5. In the tangential plane, they were distributed in an anisotropic manner around the injection. The farthest patch appeared at 4 mm from the injection site. The center-to-center distance between nearest-neighbor patches was 0.7 +/- 0.3 mm. These patches were found only within the dorsal TE and did not extend into the lower bank of the superior temporal sulcus or into the ventral part of area TE. Area TEO, which is a major afferent source to area TE, had axonal patches with spacing similar to those in area TE but with smaller sizes (0.4 +/- 0.1 mm). The results show that intrinsic horizontal axons both in area TE and in area TEO arborize in a patchy manner, as has been reported for several other cortical areas. In are TE, the size and spacing of the terminal patches match those of columns with similar stimulus selectivity. Thus, these patches may be related to the functional modularity in area TE. Vertical connections across layers and cylindrical patches of horizontal axons most likely contribute to the shared stimulus selectivity among cells within a column.
通过在日本猕猴的颞下回进行生物胞素的细胞外注射，分析了其内在连接。分析主要集中在TE区的背侧部分，该区已显示出功能性柱状组织。在进行层特异性微量注射后，在冠状切片中分析层间连接，并从切线切片中检查层内连接。在背侧TE区的不同深度进行注射后，轴突和细胞体在注射部位上方或下方呈柱状强烈标记。来自第3层的轴突成束地向白质延伸，并在第5层发出明显的侧支。也存在从下层到上层的上升轴突（例如，第4、5和6层到第3层）。在切线切片中，有大量轴突平行于软脑膜延伸。这些水平轴突，特别是第2和第3层中的那些，产生了大小为0.5±0.1毫米（平均值±标准差）、呈圆柱形的终末斑，跨越第1 - 3层，甚至延伸到第4和第5层。在切线平面上，它们围绕注射部位呈各向异性分布。最远的斑出现在距注射部位4毫米处。相邻斑的中心距为0.7±0.3毫米。这些斑仅在背侧TE区内发现，未延伸到颞上沟的下壁或TE区的腹侧部分。TEO区是TE区的主要传入源，其轴突斑的间距与TE区相似，但尺寸较小（0.4±0.1毫米）。结果表明，TE区和TEO区的内在水平轴突呈斑块状分支，这与其他几个皮质区域的报道一致。在TE区，终末斑的大小和间距与具有相似刺激选择性的柱状结构相匹配。因此，这些斑可能与TE区的功能模块化有关。跨层的垂直连接和水平轴突的圆柱形斑很可能有助于柱状结构内细胞之间共享刺激选择性。
