Code R A, Juliano S L
Department of Anatomy and Cell Biology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814.
Cereb Cortex. 1992 May-Jun;2(3):231-43. doi: 10.1093/cercor/2.3.231.
Although research is beginning to clarify the relationship between structure and functional activity in the adult cerebral cortex, little is known about cortical development in the somatosensory cortex of cats. A number of parameters were used in this study to identify functional and anatomical correlates in the developing somatosensory cortex of kittens ranging in age from 3 to 33 d: 2-deoxyglucose (2DG) uptake, cytochrome oxidase (CO) activity, Nissl staining, and AChE activity. All of these parameters were found to reflect an immaturity that evolved to the adult-like pattern by 4-5 weeks of age. Nissl staining revealed an immature laminar pattern at birth, in which layers I, V, and VI were distinct whereas layers II-IV were homogeneous in appearance. Numerous cells could be observed at the layer VI-white matter junction and throughout the white matter, a feature not found in adults. The laminar distribution of Nissl-stained cells gradually became mature by 4-5 weeks of age. CO staining was homogeneous throughout all layers, in contrast to the adult pattern, which displays laminar differentiation. In young animals, many darkly stained CO+ cells were found at the layer VI-white matter border and in the white matter, a distribution not found in the adult. AChE staining in kittens was also distinctly different from that in adults. At birth, AChE+ fibers could be found in layers I, V, and VI but were scarce in layers II-IV. In the adult, a dense network of AChE+ fibers can be found in all layers. 2DG uptake was also immature, as little stimulus-evoked activity could be observed in animals younger than 2 weeks. A dense band of metabolic activity was found in the zone between layer VI and the white matter, whether or not a somatic stimulus was delivered. These results suggest a close correlation between the developing cytoarchitecture and the emergence of a mature pattern of functional activity in the somatosensory cortex.
尽管研究开始阐明成年大脑皮质结构与功能活动之间的关系，但对于猫体感皮质的皮质发育却知之甚少。本研究使用了多个参数来确定年龄在3至33天的幼猫发育中的体感皮质的功能和解剖学相关性：2-脱氧葡萄糖（2DG）摄取、细胞色素氧化酶（CO）活性、尼氏染色和乙酰胆碱酯酶（AChE）活性。所有这些参数都反映出一种不成熟状态，这种状态在4至5周龄时演变成类似成年的模式。尼氏染色显示出生时层状模式不成熟，其中I、V和VI层明显，而II至IV层外观均匀。在VI层-白质交界处及整个白质中可观察到大量细胞，这一特征在成体中未发现。尼氏染色细胞的层状分布在4至5周龄时逐渐成熟。与显示层状分化的成年模式相反，CO染色在所有层中都是均匀的。在幼小动物中，许多深色染色的CO+细胞出现在VI层-白质边界和白质中，这种分布在成体中未发现。幼猫中的AChE染色也与成体明显不同。出生时，AChE+纤维可在I、V和VI层中发现，但在II至IV层中稀少。在成体中，所有层中均可发现密集的AChE+纤维网络。2DG摄取也不成熟，因为在2周龄以下的动物中几乎观察不到刺激诱发的活动。无论是否给予躯体刺激，在VI层和白质之间的区域都发现了一条密集的代谢活动带。这些结果表明，发育中的细胞结构与体感皮质中成熟功能活动模式的出现之间存在密切相关性。
