Mark P. Mattson
Laboratory of Neurosciences,
National Institute on Aging Gerontology Research Center, and
Department of Neuroscience,
Johns Hopkins University School of Medicine,
Baltimore, MD, USA.
As in other industrialized countries, as the average age of the population increases, the number of Canadians that suffer from neurodegenerative conditions such as Alzheimer disease (AD), Parkinson's disease (PD) and stroke is rapidly increasing. On a more positive note, the number of people that enjoy a healthy brain as they age is also increasing. The genetic and environmental factors that determine how the brain adapts to aging are beginning to be identified, and their mechanisms of action at the cellular and molecular levels are being elucidated. Although degeneration and death of neurons occur in some brain regions during normal aging, the brain is able to adapt to the cell loss by increasing the growth and synaptic connections of the remaining neurons.1 In contrast, age-related neurodegenerative disorders occur when the death of neurons is accelerated and adaptive responses are impaired or overwhelmed. During the early years of life, the brain has a remarkable ability to adapt to adversity, such that although large regions of the brain may be damaged, normal function can be restored.2 As we age, the brain loses its ability to adapt to an insult.
