Getting Older Doesn’t Stop the Genesis of New Brain Cells

Ongoing neurogenesis in the hippocampus can persist in older women and men.

Posted Apr 09, 2018

Twenty years ago, Peter Eriksson and colleagues published a landmark paper, “Neurogenesis in the Adult Human Hippocampus,” (1998) which concluded, “Our study demonstrates that cell genesis occurs in human brains and that the human brain retains the potential for self-renewal throughout life.” This was a groundbreaking discovery at the time. But, over the past two decades, there has been an ongoing debate as to whether or not older human adults can, in fact, continue to grow new neurons.

Anton Balazh/Shutterstock
Source: Anton Balazh/Shutterstock

Now, for the first time, researchers from Columbia University and the New York State Psychiatric Institute report that older women and men (who are healthy) can generate just as many new brain cells in the hippocampus via neurogenesis as younger counterparts. These findings, “Human Hippocampal Neurogenesis Persists throughout Aging,” were published April 5 in the journal Cell Stem Cell.

This study was led by Maura Boldrini, associate professor of neurobiology and research scientist in the Department of Psychiatry at Columbia University. For this study, Boldrini and collaborators performed brain autopsies on 28 healthy individuals between the ages of 14 -79 who had died suddenly. Their autopsy focus was on the state of blood vessels and recently formed neurons at the time of death.  

This is the first time post-mortem research on neurogenesis in the hippocampus has been conducted so soon after loss of life, which gave the researchers a unique window into rates of new brain cell growth across the human lifespan. Notably, the researchers found that even the oldest brains in the study were still growing new neurons.

"We found that older people have similar ability to make thousands of hippocampal new neurons from progenitor cells as younger people do," Boldrini said in a statement. "We also found equivalent volumes of the hippocampus (a brain structure used for emotion and cognition) across ages. Nevertheless, older individuals had less vascularization and maybe less ability of new neurons to make connections."

Boldrini speculates that a reduction of cognitive and emotional resilience in older age might be caused by the triad of (1) a decline in vascularization, (2) a smaller pool of neural stem cells, and (3) reduced cell-to-cell connectivity within the hippocampus.

Upcoming research by Boldrini and her team on the aging human brain will do a deeper dive into how the proliferation, maturation, and survival of neurons in the hippocampus is regulated by hormones, transcription factors, and other inter-cellular pathways. 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."

Although the most recent study by Boldrini et al. does not examine the link between aerobic exercise and increased neurogenesis in the hippocampus, countless other studies have found a link between cardiorespiratory exercise and increased human hippocampal volume. For more, see "Once and for All: Aerobic Exercise Increases Brain Size." 

References

Maura Boldrini, Camille A. Fulmore, Alexandria N. Tartt, Laika R. Simeon, Ina Pavlova, Verica Poposka, Gorazd B. Rosoklija, Aleksandar Stankov, Victoria Arango, Andrew J. Dwork, René Hen, J. John Mann. "Human Hippocampal Neurogenesis Persists throughout Aging." Cell Stem Cell (First published: April 5, 2018) DOI: 10.1016/j.stem.2018.03.015

Peter S. Eriksson, Ekaterina Perfilieva, Thomas Björk-Eriksson, Ann-Marie Alborn, Claes Nordborg, Daniel A. Peterson, and Fred H. Gage. "Neurogenesis in the Adult Human Hippocampus." Nature Medicine (1998) DOI: 10.1038/3305

Firth, Joseph, Brendon Stubbs, Davy Vancampfort, Felipe Schuch, Jim Lagopoulos, Simon Rosenbaum, and Philip B. Ward. "Effect of Aerobic Exercise on Hippocampal Volume in Humans: A Systematic Review and Meta-Analysis." NeuroImage (Published online ahead of print: November 4, 2017) DOI: 10.1016/j.neuroimage.2017.11.007

Elena W. Adlaf, Ryan J. Vaden, Anastasia J. Niver, Allison F. Manuel, Vincent C. Onyilo, Matheus T. Araujo, Cristina V. Dieni, Hai T. Vo, Gwendalyn D. King, Jacques I. Wadiche, Linda Overstreet-Wadiche. "Adult-Born Neurons Modify Excitatory Synaptic Transmission to Existing Neurons." eLife (2017) DOI: 10.7554/eLife.19886

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