Ageing, stimuli and changes in the brain

Possible environmental and aging influences on learning and memory and the laminar distribution of astrocytes in the dentate gyrus were studied. Performance in episodic-like and spatial memory tests was correlated with astroglial changes in the dentate gyrus estimated by a bias-free method based on stereology. Taken together, the data suggest that maintaining the animals in an environment poor in sensorimotor and cognitive stimuli may be associated with abnormal cognitive development and this with changes in the laminar distribution of astrocytes in the dentate gyrus. Considering that astrocytosis was the element shared by environmental enrichment and aging, it is suggested that the astrocytes increased in one condition and the other are expressing different phenotypes.