April 24, 2018

In the April 5, 2018 issue of the journal Cell Stem Cell, Columbia University researchers report that healthy older individuals generate as many new cells in the brain’s hippocampus (an area involved in memory and emotion) as young adults. An age-associated reduction in the ability of the brain’s hippocampus to generate new cells has been observed in mammals — a phenomenon that was believed to occur in humans as well.

"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," commented lead author Maura Boldrini, who is an associate professor of neurobiology at Columbia’s Department of Psychiatry.

Dr. Boldrini and colleagues examined hippocampi of 28 men and women between the ages of 14 and 79 who had undergone sudden death. The subjects had not exhibited cognitive impairment or neuropsychiatric disease, which can impact new brain cell generation. The researchers found that the oldest brains still generated numerous new cells. "We found similar numbers of intermediate neural progenitors and thousands of immature neurons," they report. However, they observed that older brains exhibited less angiogenesis (formation of new blood vessels) and brain plasticity than younger brains, and a smaller quiescent progenitor cell pool (which are actively maintained reserve cells that can differentiate to form one or more types of cells) in the anterior-mid dentate gyrus area of the hippocampus, with no changes in the posterior dentate gyrus.

"We found that older people have similar ability to make thousands of hippocampal new neurons from progenitor cells as younger people do," Dr. Boldrini explained. "We also found equivalent volumes of the hippocampus across ages. Nevertheless, older individuals had less vascularization and maybe less ability of new neurons to make connections."

"An exhausted quiescent progenitor pool, and less vascularization of the neurogenic niche resulting in less neuroplasticity, may explain some age-related, cognitive-emotional changes," the authors conclude. "Future studies are needed to examine the cognitive and emotional correlates of these indices of neuroplasticity and the potential of exercise, diet, and medications to enhance healthy aging."