A new study by Columbia University reveals that the brain continues to make hundreds of neurons, a process called neurogenesis, even after a person reaches their late 70s.
In the study published in Cell Stem Cell, lead author Dr. Maura Boldrini, of the university’s psychiatry department, and her colleagues, looked into the process of neurogenesis by studying the brains of deceased individuals with ages ranging from 14 to 79.
The main goal of the research was to see how aging affects the production of neurons, a subject which has been up for much scientific debate for years.
Aging And Brain Cell Production
The brain’s function has been a significant point of interest, notably the creation of new neurons. Animal studies made on primates and mice revealed a slowing down of neurogenesis as the organisms aged. Boldrini and her colleagues wanted to see if the same phenomenon exists in humans.
Using the brains from the deceased individuals, they looked for evidence of neuron production in various stages of development, including stem cells, progenitor cells, which would eventually become neurons, immature neurons, and fully developed neurons.
By looking at the hippocampus, the part of the brain in charge of resiliency, emotional control, and memory, they tried to look for evidence of continued neuron production. Based on the results, immature neurons and progenitor cells did not vary irrespective of age, which means that the brain continues neurogenesis, even in older people. Hence, the brain can still produce neurons for individuals as old as 79.
Old Brain Vs. Young Brain
While discovery that the brain can still make new neurons is promising, there’s a catch. There’s a significant decrease in proteins that help neurons make new connections as a person gets older.
“We don’t find fewer of the new neurons or fewer of the progenitors of new neurons, but we find that new neurons might make fewer connections,” Boldrini said.
Boldrini explains the implication to be lesser emotional resiliency and memory loss in older individuals.
This study comes about a month after the University of California, San Francisco published a study in Nature revealing that the oldest person to show evidence of young neurons is from the brain of a 13-year-old.
As reported by Los Angeles Times, the study authors issued a statement on the new findings, highlighting that they looked into the cell shape and the structure using the light and electron microscope.
“That revealed that similarly labeled cells in our own adult brain samples proved to be neither young neurons nor neural progenitors, but rather non-neuronal glial cells expressing similar molecular markers.”
In response, Boldrini pointed out that they had access to the entire hippocampus region of the brain samples which were immediately frozen at minus-112 degrees Fahrenheit to avoid tissue degradation. Meanwhile, the UC San Francisco researchers received thin slices of the brain from samples from the U.S., China, and Spain which were not preserved in the same manner hence the difference in their findings as to the creation of neurons in older people.
“In science, the absence of evidence is not evidence of absence. If you can’t find something it doesn’t mean that it is not there 100%.”