A modified Golgi staining protocol for use in the human brain stem and cerebellum

The Golgi silver-impregnation method established itself as an important technique for distinguishing morphology at the individual neuron level. This technique has been especially useful for studying human neuroanatomy because it works on postmortem tissue but it is also unreliable and capricious. In this report, we describe a simple technique that was applied to human autopsy and tissue-bank material yielding useful results for the study of neuronal morphology in the brain stem and cerebellum. Human adult brain stems had been immersion-fixed in formalin for a period of time ranging from weeks to months. Brain stem tissue was cross-sectioned into 3-5mm thick slabs, centered about the cochlear nucleus. Slabs were processed under continuous vacuum (22-26 in. of Hg), a procedure that promoted penetration of reagents into the tissue. Tissue was sectioned using a Vibratome and mounted for light microscopy. The results demonstrated improved staining of neurons in the brain stem. Staining of the large synaptic endings of auditory nerve fibers called end bulbs of Held in the cochlear nucleus was especially evident. These results suggest that an age-graded series could be conducted to describe the development of these large auditory endings in humans.