Do our brain cells die as we age? Researchers say no

Present-day theory says that adults don’t grow new neurons. Scientists believe that memory may begin to fail because no new neurons continue to grow in the hippocampus – a part of the brain responsible for memory, emotion and cognition.

A study in the American journal Cell Stem Cell just might throw all previous scientific research out the window! Healthy older men and women can generate just as many new brain cells as younger people, it finds.

Researchers from Columbia University and the New York State Psychiatric Institute examined the brains of 28 previously healthy people aged 14 to 79 who had died suddenly. They found that people aged 79 had just as many new neurons forming in the hippocampus as those who were 14. Even the oldest brains produced new brain cells.

Lead author Dr Maura Boldrini, associate professor of neurobiology at Columbia University, told the findings suggest that the elderly remain more cognitively and emotionally intact than generally believed.

The findings represent the first time researchers explored newly formed neurons and the state of blood vessels within the entire human hippocampus soon after death. The team determined that study subjects weren’t cognitively impaired and hadn’t suffered from depression or taken antidepressants. Such conditions could impact the production of new brain cells.

Neurogenesis – the ability to generate new hippocampal cells – declines with age in primates. This decreasing production of neurons was believed to occur in ageing humans, too. Now the study suggests that the neurogenesis process continues in the adult human hippocampus.

The scientific community considers that memory may begin to fail because no new neurons grow in this part of the brain. Speaking to the UK’s ‘Independent’, Dr Boldrini said: “We found that older people have similar ability to make thousands of hippocampal new neurons from progenitor cells as younger people do. We also found equivalent volumes of the hippocampus across ages.”

But the researchers also revealed fewer blood vessels and connections between cells in the older brains. The older the individual, the less new blood vessels he or she forms. Comparing perfectly healthy brains to diseased ones could open the door to developing new treatments for psychological and neurological conditions such as Alzheimer’s disease.

“We all know people that are in their nineties and are sharp,” added Dr Boldrini in the ‘Daily Mail’. To some extent, her research disputing previous theories that neurons stop developing after adolescence now explains why that’s possible.