The Golgi Methods

Abstract

The Golgi methods continue to be the methods of choice for microscopic study of individual neurons and their processes in the central nervous system. They were introduced over a century ago (Golgi 1873) and went through a period of very productive use for some 30–40 years afterwards. Subsequently, these methods have been relatively neglected for many years. Now again, they are widely employed in the field of neurobiology. They are key techniques, because they provide precisely the most crucial information for organizing, correlating, and interpreting data from a variety of methods and disciplines. And today, virtually all significant research in the neurosciences is interdisciplinary in at least its conception, if not its execution. For example, a study of the neuronal architecture in the medial geniculate body with the Golgi methods provided more insight into the functional organization of this structure than previous years of study with microelectrode recordings (see Morest 1965 a, b). The reason for this is that the Golgi methods provide unsurpassed dem-onstrations of the processes of neurons, their axons, and dendrites. These are the processes which establish the synaptic organization of the nervous system. Detailed observations of axonal endings, dendritic spines and branches, and geometrical patterns of the axonal plexus and dendritic fields can be made on specific types of neurons. By correlating such observations with silver degeneration methods it is possible to relate the morphology of individual types of neurons to their connections and hence to relate them to specific functional contexts (see Morest 1965 b). In recent years much more elaborate correlations between a variety of techniques have been possible, e.g., between the findings with Golgi, silver degeneration, Nissl, and electron microscopic methods, on the one hand, and electrophysiological data on the other hand (see Morest et al. 1973; Morest 1975 a, b).