The ageing brain
John Woulfe, Doug Gray, Carole J. Proctor
Abstract
Ageing is accompanied by loss of cognitive function, but the effects, pattern, and extent of this are highly variable among individuals. At one end of the spectrum, symptoms of neurodegenerative disorders, such as memory loss in Alzheimer’s disease, are observed. While the underlying cellular mechanisms have been studied extensively, less is known about the mechanisms leading to brain ageing per se. It is believed that there is a continuum between ageing and classical neurodegeneration. However, there is evidence of neuronal and glial changes at the cellular and molecular levels that are unrelated to the pathological changes observed in disease. These age-related changes may lower the threshold for neurodegeneration pathologies. The underlying mechanisms are complex and also involve stochastic events such as random molecular damage leading to inter-individual variability in the rate of cognitive decline.