Understanding brain aging has to be research priority. The average age of people in the US is increasing. This means that there are more older people at risk for diseases that occur as people get older, such as Alzheimer’s.
In people, the size of the brain decreases as they get older. The deep grooves on the surface of the brain (called sulci) get bigger, and the fluid-filled areas inside the brain (ventricles) get larger. It all amounts to loss of brain tissue, and many people believe that this loss of brain tissue may be related to cognitive changes that also occur with aging, like problems in remembering things.
That’s why a recent study about brain size in chimpanzees is interesting. It shows that chimpanzees, who in many respects are similar to humans, have brains that don’t get smaller as they get older. Chimpanzees also don’t live as long as humans. The authors of the study argue that the decrease in brain size with increasing age that is seen in humans may have something to do with how long humans live. They suggest that the longer life span of humans may be in part the result of an evolutionary trade-off in which increased life span may have the cost of increased age-related neurodegeneration.
Sherwood CC et al. Aging of the cerebral cortex differs between humans and chimpanzees. Proceedings of the National Academy of Sciences, PNAS early edition (online) DOI: www.pnas.org/cgi/doi/10.1073/pnas.1016709108