| Reduced brain mass |
| Reduced number of neurones |
| Enlargement of the ventricles |
| Increased lipofuscin deposition in neurones |
| Leptomeningeal thickening |
| Reduced number (denudation) of dendritic spines |
| Astrocyte hypertrophy (gliosis) |
| Argyrophilic (senile) plaque formation |
| Corpora amylacea formation |
| Perivascular haemorrhage is reported to be common in very old dogs |