Rathjen Stefan, Schmidt Kerstin E, Löwel Siegrid
Forschergruppe Visuelle Entwicklung und Plastizität, Leibniz-Institut für Neurobiologie, Brenneckestr. 6, 39118 Magdeburg, Germany.
Exp Brain Res. 2003 Mar;149(2):151-8. doi: 10.1007/s00221-002-1342-z. Epub 2003 Jan 11.
The primary visual cortex (area 17) of cats continues to grow substantially during early postnatal development. To assess the implications of this growth for the organization of visual cortical maps, we analysed both postnatal growth of area 17 and the spacing of ocular dominance columns in the same animals using 2-deoxyglucose autoradiography to label cortical activation patterns. Quantitative analyses of area size and column spacing were performed on flat-mount sections of the cortical hemispheres. Our analysis of the surface area revealed an average increase of the size of area 17 between the third and tenth postnatal weeks by about 51%. About 75% of this increase occurred during the third and sixth postnatal weeks (size increase of 37%). However, the distance between adjacent columns did not exhibit a similar increase but rather remained constant during the same postnatal period. Since cortical growth is not accompanied by an increased spacing of ocular dominance columns, new functional modules must somehow be added during the first postnatal weeks to occupy the enlarging cortical sheet. Possible mechanisms underlying the formation of new modules are discussed.
猫的初级视觉皮层（17区）在出生后的早期发育阶段会持续大幅生长。为了评估这种生长对视觉皮层图谱组织的影响，我们使用2-脱氧葡萄糖放射自显影技术标记皮层激活模式，分析了同一批动物中17区的出生后生长情况以及眼优势柱的间距。对皮质半球的平铺切片进行了面积大小和柱间距的定量分析。我们对表面积的分析显示，出生后第三周和第十周之间，17区的大小平均增加了约51%。其中约75%的增长发生在出生后第三周和第六周（大小增加了37%）。然而，相邻柱之间的距离并没有呈现出类似的增加，而是在同一出生后时期保持不变。由于皮层生长并未伴随着眼优势柱间距的增加，因此在出生后的最初几周内，必须以某种方式添加新的功能模块，以占据不断扩大的皮层片。本文讨论了新模块形成的潜在机制。
