Although our brains are always renewing—in a process known as neurogenesis—the connections between neurons become less efficient as we age, and this could be the reason older people have cognitive problems such as memory loss.
Researchers from Columbia University in New York analysed the brains of 28 people, aged between 14 and 79, who had died suddenly but who had no mental problems such as depression or dementia. All the samples showed signs of neurogenesis, including the formation of new neurons—in fact, they all had similar patterns of growth throughout the hippocampus.
The one difference was that samples from the older subjects had less angiogenesis; in other words, they weren't forming as many blood vessels and so the new neurons weren't able to connect as efficiently as they were doing in younger samples.
Although scientists have known for 30 years or more that neurogenesis continues to occur throughout life, the Columbia team is one of the first to actually witness it in a range of samples.
Their findings open the door to better therapies for dealing with dementia, memory loss and Alzheimer's: concentrate on the connective blood vessels, not the brain tissue—that's taking care of itself just fine.