Science and Your Long Life Brain
Science and Your Long Life Brain
Dr David Lewis, BSc(Hons), D.Phil. FISMA, FINSTD, C.Psychol
Brain ageing
Let’s start with the bad news about brain ageing and then see why, for the vast majority of us as we grow older, it’s really not bad news after all!
As we age our brain changes.
For one thing it shrinks.
Brain shrinkage
In youth our brain weighs around 1.5 kg (approximately 3lbs) but by the time we celebrate our 65th birthday its weight may have dropped to 1.2 kg.
Furthermore the natural gaps between the folds of the outer layer of the brain - the neocortex - widen and two large spaces within the brain (the ventricles) also enlarge.
Brain plaques and tangles
Unhelpful structural changes also take place, including the spread of neuritic plaques and neurofibrillary tangles, the latter formed from the remains of dead brain cells. Since the density of neuritic plaques is directly related to a decline in mental ability, and since both plaques and tangles are implicated in Alzheimer’s disease related dementia, this is potentially very bad news indeed.
Brain cell loss
Finally, from early adulthood onwards we lose brain cells. Worse still these are postmitotic cells, meaning they are irreplaceable by normal cell division. Brain cells are lost especially in the crucial frontal regions, which are responsible for most of what makes up both our unique individual personality and our intellectual ability.