Four modified silver methods for thick sections of formaldehyde-fixed mammalian central nervous tissue: 'dark' neurons, perikarya of all neurons, microglial cells and capillaries.

Four reliable silver methods for the visualization of acute or advanced phases of neuronal damage have been modified so that they can be performed with good results on materials freshly fixed with transcardial perfusion of buffered formaldehyde for other silver methods and immunocytochemical techniques. The four modified methods respectively stain: (1) the somata and dendrites of 'dark' (impaired) neurons, (2) the perikarya of all neurons, (3) microglial cells, and (4) capillaries. Without the present modifications the 'dark' neuron method is only effective with glutaraldehyde fixation while the other three methods predominantly stain myelin in freshly fixed mammalian nervous tissue.