Age-related changes in the cholinergic components within the central nervous system of CW1 female mice. I. Structural analysis.

Histomorphometric analysis of age-related structural changes in the brain was performed in CW1 female mice, 3, 9, 24 and 32 months of age. Cholinergic regions, such as the hippocampus, NBM and the medial habenula (MH) were investigated in more detail focusing on morphological parameters. The thickness of the frontoparietal cortex (FPC), and the surface area of the dorsal hippocampus and the MH were found to decrease significantly from 9 to 24 months of age. Except for the unique appearance of pseudo-cysts within the FPC, the structural changes culminated by 24 months. Cells' degeneration, in the CA3 hippocampal subfield, was noted already by 9 months of age whereas in other regions the cells' surface area decreased only between 9 and 24 months. Lipofuscin accumulation was most pronounced in the large neurons of the cortex, hippocampus and NBM at 24 months of age.