A study of the vascular supply to the external granular layer of the postnatal rat cerebellum.

Using a technique of perfusion with a mixture of gelatin and India ink, followed by clearing with methyl salicylate, the vasculature of the external granular layer of the rat cerebellum was studied. This transient layer remains poorly vascularised throughout it existence, and it seems probable that its main blood supply comes from the capillary net of the pial membrane. Once the cells of the external granular layer have disappeared, by the twenty first postnatal day, capillaries ramify in the outer reaches of the cerebellar cortex, and within a few days the region occupied by the external granular layer is, in terms of its vascularisation, indistinguishable from the rest of the cerebellar cortex.