14 DAY TRIAL // According to a professor at the Harvard School of Medicine (HMS), it may be that the root cause of cognitive impairments that humans experience more and more late in life is our evolution as a species. When compared to other intelligent animals on the planet – such as apes, crows, dolphins and whales – humans exhibit an unusual tendency of developing conditions such as Alzheimer's. According to HMS pathology and neurology professor Bruce Yankner, evolution is the only possible answer that can explain this dilemma, PhysOrg reports.
The Harvard Museum of Natural History is currently hosting a series of lectures entitled “Evolution Matters,” and Yankner was invited to speak on March 28. “Something has occurred in evolution that makes our brain susceptible to age-related change,” he said to the audience on Sunday night. The expert and his team are working on brain aging studies, and they have been conducting research into how the aging brain promotes the development of conditions such as Alzheimer's Disease (AD) and Parkinson’s for many years. In the course of their work, the experts noticed that AD was one of the most prevalent diseases among seniors today.
“It is clear that cognitive impairment and decline is one of the emerging health threats of the 21st century,” Yankner explained at the meeting. He added that progresses recorded in medicine over the past few decades had multiplied the number of elderly people considerably. More than 50 percent of those past the age of 85 develop AD, and a lot more people today pass this age than anytime in history. Under these circumstances, the number of individuals with Alzheimer's is bound to increase considerably. In the UK alone, the number of seniors is expected to double by 2050.
And this surge in AD cases is also prompting more and more research into the condition's causes and underlying triggers. The HMS expert said that, most likely, the fact that our brains were big was not a cause in itself. But the condition evolved relatively recent in the history of our species, and so its cause must be evolutionary. One possible explanation is that cognitive decline is caused by the very cortical complexity we take so much pride in, as well as by the new clusters of cells that are formed as a result.
“Aging is a balance between wear and tear and repair. Where you wind up in that balance determines how you do,” Yankner added. Genetic studies have shown that a number of genes reduce their activity in old age, causing the brain to become more exposed to the harmful actions of mutations and other, environmental factors.