[The neuroethological basis of learning and memory decline in aged rats]

The spatial reference and working memory abilities, GFAP-positive astrocytes and GABAergic interneurons were studied quantitatively in young, aged memory-unimpaired and aged memory-impaired rats according to their learning and memory abilities in the Morris water maze. The results showed that the prominent behavioural features of the aged memory-impaired rat were a change in the searching pattern, a decrease in the spatial reference memory, no significant decrease in the spatial working memory was observed. The decrease of GABAergic neurons, and the increase of GFAP-positive astrocytes in the dentate gyrus of the aged memory-impaired rat were more obvious than the other two groups. The main abnormalities of morphologic indexes were closely correlated with the decline of learning and memory in the aged rat.