Postnatal development of the cerebellar cortex in the rat. I. The external germinal layer and the transitional molecular layer

作者：Joseph Altman · 发表于：The Journal of Comparative Neurology · 年份：1972 · DOI：10.1002/cne.901450305 · 被引用次数：918 · 研究领域：Vestibular and auditory disorders、Hearing, Cochlea, Tinnitus, Genetics、Neuroscience of respiration and sleep

Abstract The multiplication of cells in the proliferative zone of the external germinal layer and the early steps in the differentiation of basket, stellate and granule cells were studied in the cerebellar cortex of rats aged 0, 3, 5, 7, 10, 12, 15, 21 and 30 days with histological, histochemical, autoradiographic and electron microscopic techniques. Between 0–9 days the proliferative zone has a constant depth of four to five cells; the bipolar cells in the underlying premigratory zone increase in depth during this period from 0–6 cells. Thereafter, there is a decline in the cell depth of both zones. In the premigratory zone there is a gradient in the length of the extruded processes of the bipolar cells (concentration of such profiles), the future parallel fibers. Presumably when the latter reach their final length, the cell body migrates downward and the parallel fiber becomes part of the upper zone of the molecular layer. Thus, parallel fibers are progessively formed on the surface of others from the bottom upward by a stacking process and the external germinal layer, as a consequence, is continually pushed upward. This design makes possible the assembly of a matrix of very long, thin and straight beams of horizontally oriented parallel fibers which pile up vertically according to their age. When synaptogenesis starts during the second week in the molecular layer the enlarging junctional processes produce a spurt in the growth of this layer. Basket cells which are formed i...