Dark neurons: a significant artifact: the influence of the maturational state of neurons on the occurrence of the phenomenon.

In cerebella of young rats, killed by decapitation, dark Purkinje cells were readily observed in animals from 16 days of age onward. In younger animals (from 0-12 days of age) these dark neurons were never observed. The author agrees with Cammermeyer and others that dark neurons are an avoidable artifact. The findings presented suggest, however, that the possibility of the occurrence of this type of artifact depends on the maturational state of the neurons concerned.