Humphrey A L, Skeen L C, Norton T T
J Comp Neurol. 1980 Aug 1;192(3):549-66. doi: 10.1002/cne.901920312.
The topographic organization of the orientation column system in the tree shrew striate cortex was examined by using 2-deoxyglucose autoradiography to map the cortical sites of increased metabolic activity produced by visual stimulation with stripes of a single orientation. Awake experimental tree shrews (freely moving, restrained, or paralyzed) were given injections of deoxyglucose label and then stimulated with vertical, horizontal, or oblique stripes for 45--75 min. Autoradiographs of coronal sections through the striate cortex revealed regularly spaced radial zones of increased deoxyglucose uptake 150--350 micrometers wide, extending from the cortical surface to the white matter, separated by interzone regions of lower uptake. The radial zones were most densely labeled and distinct in layers I--IIIb and least distinct in layer IV, which was continuously and densely labeled throughout both the radial zone and interzone regions. These radial zones, which were not present in control animals that viewed many orientations, reflect the locations of cortical cells activated by a single stimulus orientation. Reconstructions of the radial zones from serial sections produced maps of the distribution of increased deoxyglucose uptake across striate cortex. The maps reveal a highly organized system of narrow, parallel bands that are slightly wavy and have a mean spacing of 530 micrometers. The band pattern was confirmed in sections cut tangential to the cortical surface and was similar in animals stimulated with either vertical or horizontal stripes; the bands consistently abut the 17--18 border at nearly right angles and extend across the striate cortex in a generally posteromedial direction. These patterns of increased deoxyglucose consumption confirm the anisotropic distribution of orientation-selective cells across the tree shrew striate cortex, suggested in the preceding microelectrode study (Humphrey and Norton, '80). The density distribution of label within the bands further suggests that the anisotropy is due to a system of parallel, somewhat wavy iso-orientation lines arranged roughly perpendicular to the 17--18 border.
通过使用2-脱氧葡萄糖放射自显影技术，来绘制由单一方向条纹的视觉刺激所产生的代谢活性增加的皮质位点，从而研究了树鼩纹状皮质中定向柱系统的地形组织。对清醒的实验树鼩（自由活动、受限或瘫痪）注射脱氧葡萄糖标记物，然后用垂直、水平或倾斜条纹刺激45 - 75分钟。通过纹状皮质的冠状切片放射自显影片显示，脱氧葡萄糖摄取增加的区域呈规则间隔的放射状带，宽150 - 350微米，从皮质表面延伸至白质，被摄取较低的中间区域分隔开。放射状带在I - IIIb层标记最密集且明显，在IV层最不明显，IV层在整个放射状带和中间区域都持续且密集地被标记。这些放射状带在观看多种方向的对照动物中不存在，反映了由单一刺激方向激活的皮质细胞的位置。从连续切片重建放射状带，生成了跨纹状皮质脱氧葡萄糖摄取增加分布的图谱。这些图谱揭示了一个高度有组织的系统，由窄的、平行的带组成，这些带略有波浪状，平均间距为530微米。在与皮质表面相切的切片中证实了带模式，在用垂直或水平条纹刺激的动物中相似；这些带始终以近直角邻接17 - 18边界，并在纹状皮质中大致向后内侧方向延伸。这些脱氧葡萄糖消耗增加的模式证实了在前一项微电极研究（Humphrey和Norton，1980年）中所暗示的，树鼩纹状皮质中方向选择性细胞的各向异性分布。带内标记的密度分布进一步表明，各向异性是由于大致垂直于17 - 18边界排列的平行、略有波浪状的等方向线系统所致。
