Researchers dispute the popular notion that the brain stops growing as you get old. They say seniors develop as many new brain cells as younger people.
Your days of bungee jumping may be behind you, but your brain — contrary to popular wisdom — continues to be productive.
A study released today in the journal Cell Stem Cell concludes that healthy older men and women generate just as many new brain cells as younger people.
Many scientists believe that the adult brain is in effect hardwired and doesn’t grow new neurons.
Dr. Maura Boldrini, a professor of neurobiology at Columbia University in New York, is the study’s lead author. She said the findings suggest that older adults remain cognitively and emotionally intact.
“This hasn’t been studied systematically before,” she told Healthline. “But in rodents and other animals, we don’t see continued brain growth.”
As a result, many scientists assumed that people were like rodents, only bigger.
In rodents and primates, the ability to generate new hippocampal cells declines with age.
Fewer new neurons and shrinking of the part of the hippocampus thought to help form new episodic memories were believed to occur in aging humans as well.
In this latest study, the researchers from Columbia University and New York State Psychiatric Institute performed autopsies on hippocampi from 28 previously healthy individuals aged 14 to 79 who had died suddenly.
None of the subjects had been cognitively impaired. They also hadn’t been diagnosed as depressed nor had taken antidepressants. Boldrini said she and her colleagues had previously found that such medication had affected the production of new brain cells.
Because of the difficulty of finding enough subjects who fit the study requirements, the researchers acquired most of the samples from Macedonia.
Further studies will focus on a more diverse cohort, Boldrini said.
The researchers discovered that the brains of even the oldest subject they studied produced new brain cells.
“We found similar numbers of intermediate neural progenitors and thousands of immature neurons,” they wrote.
Nevertheless, older individuals form fewer new blood vessels within brain structures and possess a smaller pool of progenitor cells — descendants of stem cells that are more limited in their capacity to differentiate and renew themselves.
Boldrini said that other studies had a long postmortem period in which to conduct their research, as long as 48 hours. This is the first time researchers looked at newly formed neurons and the state of blood vessels within the entire human hippocampus soon after death.
Boldrini, who has been studying these issues for a decade, says more work is needed.
“We could compare this to those with a disease or cognitive impairment,” she said.
One of the questions Boldrini wants to answer is how human beings, who retain a large hippocampus throughout life, differ from the rest of the animal kingdom.
She doesn’t know yet if this discovery about the hippocampus will eventually lead to treatments for dementia, depression, and other ailments that affect healthy aging.
“It is possible that ongoing hippocampal neurogenesis sustains human-specific cognitive function throughout life and that declines may be linked to compromised cognitive-emotional resilience,” she said.
She’s not the only person concerned about the aging brain.
Alzheimer’s disease is now more feared than cancer, according to Dr. James Hendrix, director of global science initiatives for the Alzheimer’s Association.
Hendrix noted that it was too soon to tell if this latest study will lead to some useful treatment, but he told Healthline, “I am more hopeful today than four years ago when I joined this organization.”
Hendrix said the association has been involved in a two-year study to preserve brain health through lifestyle changes.
The group recommends combining physical activity, healthy nutrition, social and intellectual challenge, and improved self-management of medical conditions as a prescription for everyone.
While studies such as Boldrini’s are interesting, “they are no silver bullet,” Hendrix said. But lifestyle changes may put off the onset of disease.
His comments are echoed by Dr. Douglas Scharre, director of the Division of Cognitive Neurology at The Ohio State University Wexner Medical Center.
“It’s nice to know how older individuals can form new neurons,” he told Healthline. “And it’s important to know if different pathologies change this.”
Scharre would like to know how the brain differs in people with health issues, since the subjects in the current study were chosen specifically because they were healthy.
“Many individuals have memories different from those found in people undergoing normal aging. They may be slower to react,” he said. “Those aging well were fit in their younger days, too.”
His prescription for aging well: Socialize and exercise.
For example, it’s not enough to sit on the couch and do a crossword puzzle. Scharre advises you to take the puzzle to the mall and talk to people about the clues.
“That’s interacting with others, not playing video games,” he said.
Or maybe even try some bungee jumping.