Unlike humans, chimpanzees’ brains don’t shrink as they get older. That means that, so far, people seem to be the only lucky species whose brains wither with age, according a report by Prof. Chet Sherwood and his colleagues in the July 25, 2011 online Proceedings of the National Academy of Sciences.
In the new study, Sherwood and his colleagues focused on chimpanzees, which have some of the most developed brains and longest life spans among primates. The researchers wondered if chimps experience brain decline in old age similar to that seen in humans.
The researchers scanned the brains of 99 chimpanzees with ages representing the entire adult life span, from 10 to 51 years. For comparison, the team imaged the brains of 87 humans from 22 to 88 years old. The human scans confirmed what other studies had found: All brain regions measured showed shrinkage with age. But chimp brains didn’t get smaller with age.
Sherwood points out that the results don’t answer a fundamental question for human evolution: “Why would we be built in such a faulty way that leads to this degeneration in our brains?” he asks. Perhaps a long life span is worth the drawback. Big brains and long life spans may free up older members of the population to look after the youngsters, he speculates.
The research by Professor Sherwood and colleagues was highlighted by numerous national and international news organizations, including BBC News, the Wall Street Journal, and CBS News, and featured in Discover magazine and Science blogs.
For more information and the original article, go to http://www.pnas.org/content/early/2011/07/20/1016709108.abstract