Changes with age in the volume proportions of the hippocampal components

ABSTRACT

Stereological techniques were employed to examine changes with age in the volume proportions of different hippocampal components. The adult values were compared with those recorded in previous literatures. A significant decrease was observed in the volume proportions of the granular layer in the dorsal lip of dentate gyrus between two and five months of age. Comparing this results with the observed stability in the volume proportions of the granular layer in the whole dentate gyrus led to a conclusion that ventral lip of dentate gyrus showed a stage of increasing growth rate compared with the dorsal lip during this period of life. Stability of the volume proportions of dentate gyrus components was observed between five through to twenty-four months of age. An increase in the volume proportions of the pyramidal layer in the hippocampus between two and five months was attributed to an increase in the volume of the pyramidal neurons in this period. The dentate-to-Ammon's horn volume ratio showed a significant decrease between twelve and fourteen months which was suggested to reflect hippocampal functional change with ageing