Influence of cognitive stimulation on central cholinergic system of transgenic mice for Alzheimer's disease

Abstract

Aging is a world phenomenon where biological, cognitive and social adaptations are observed. During this process, a loss of the cognitive capacities may occur. Besides that, there is a high prevalence of Alzheimer’s disease (AD) among the elderly. AD is a progressive and irreversible neurodegenerative disease that leads to an intensive loss of memory. Memory processes are modulated by humor and involve many neurotranmiter systems. Cholinergic system is an example. In recent studies we showed that physical activity can activate cholinergic system in brain areas related to the reward pathway, which could lead to a positive effect in long term memory. Besides, in another work we observed increases in density of alpha7 nicotinic receptor in the amygdala after cognitive stimulation of animals submitted to a neurodegeneration model, which suggests an important role for the cholinergic system to the memory reinforced by aversive stimulus (fear circuitry).This project will evaluate the memory of transgenic mice for the AD after chronic cognitive stimulation (using active avoidance and enriched environment methods) and evaluate, by autoradiography, if there are alterations in brain cholinergic system, mainly in the density of alpha7 nicotinic receptors in amygdala and in the nucleus accumbens. This study can provide new insights for the understanding of the role of the cholinergic system in memory of elderly people with or without neurodegenerative disorders. (AU)