Researchers have long thought that the aging brain stops producing new cells. However, findings of a new study say otherwise.
New research suggests that the human brain keeps making new neurons even as it gets older.
Right Collection Of Brains To Study Effects Of Aging
In a study published in the journal Cell Stem Cells, Maura Boldrini, from Columbia University, and colleagues studied the brains from corpses of people who were between 14 and 79 years old at the time of their death.
The brains show no signs of any major disorder, brain samples did not come from drug users or people who used antidepressants either. This selection of samples excludes possible factors which may stimulate cell growth.
"We thought we had the right collection of brains to be able to look at the effects of aging, per se, without having these confounding factors ... not too many brain collections in the world actually have information about this," Boldrini said.
Neurons Form In Aging Brain
The researchers studied the hippocampus, taking a closer look at the newly formed brain cells and the state of blood vessels in the region of the brain that plays an important role in emotions, spatial navigation, and memory.
Boldrini and her team counted the number of newly formed neurons in the hippocampus using specialized computer software and found that that the older brain had as many new cells as the younger brains.
"We found that older people have similar ability to make thousands of hippocampal new neurons from progenitor cells as younger people do," Boldrini said. "We also found equivalent volumes of the hippocampus (a brain structure used for emotion and cognition) across ages."
Why The Brain Deteriorates In Old Age
The researchers, however, observed that older brains formed fewer blood vessels and possessed a smaller pool of progenitor cells -- the early descendants of stem cells that turn into neurons.
Boldrini and colleagues think that the deterioration of the brain in old age could be attributed to this smaller pool or neural stem cells, reduced connectivity among cells within the hippocampus and decline in blood vessels.
"Healthy older subjects without cognitive impairment, neuropsychiatric disease, or treatment display preserved neurogenesis," Boldrini and colleagues wrote in their study. "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."
Implications
The findings may help scientist better understand what causes dementia and how to prevent it. The neurological condition currently affects about 5.4 million Americans and is the fifth leading cause of deaths in adults 65 years old and above.
