RESUMO
A number of studies attempting to identify specific risk factors for dementia have noted an inverse relationship between educational background and the likelihood of developing dementia. This idea has been somewhat controversial as educational background can introduce a number of confounding factors that generally affect health and lifestyle. Despite these reservations, there is mounting evidence to support the concept of education (or increased mental activity) producing a functional reserve in the brain, a process that provides some protection against the clinical manifestation of dementia. Long-term potentiation (LTP) is a recognized neural correlate of learning and memory. We have shown recently that LTP reduces the sensitivity of hippocampal neurons to agonists of the neurotransmitter glutamate; additionally, we have reported that LTP protects the neurons from the effects of acute hypoxia. Given that the effect of hypoxia on neurons involves over-stimulation by glutamate, and hypoxia has been implicated in the aetio-pathology of some types of dementia, our observations suggest that LTP has a protective effect on neuronal tissue. Such an interaction offers a physiological basis for the epidemiological evidence that lifelong learning can protect a person from some types of dementia.