Silver impregnation of the prefrontal cortices in the brains with long postmortem delay.

Silver impregnation was performed histologically on the prefrontal parts of brains, which had long postmortem delay of one month while under 4 degrees C refrigeration. The brains were from individuals from 60+- to 80+-years old. It was evident from these specimens that, as a whole, the outer layers of the brains degenerated first while the inner layers remained to be silver stainable and had near normal morphology after silver impregnation, even in the oldest specimens. Comparatively, the postmortem degeneration was worse in the outer cortical layers of the older individual when compared with the younger.