Speciale vlekken voor het centrale zenuwstelsel

In het centrale zenuwstelsel onderscheiden we de grijze stof waar zich voornamelijk de cellichamen van neuronen bevinden en de witte stof die bestaat uit bundels zenuwvezels: axonen of cylindraxen, omwikkeld met Schwann-cellen.

Neurons are not the only cellular constituents, there are also support cells (the cells of the neuroglia) and blood capillaries.

Two particular types of staining are used to study nervous tissue in the central system: "bichromes" and silver impregnations. "Bichromes", like Dominici, combine a basic dye (toluidine blue) showing basophilic structures (Nissl's body, the nucleus) and an acidic cytoplasmic dye. The absence of connective tissue in the central nervous system renders the use of a third dye unnecessary. The techniques of silver impregnation make it possible to overcome the lack of colorability of the cytoplasmic prolongations of the nerve cells by revealing the cytoskeleton (neurofibrils) which is particularly abundant in these extensions.