Posted on May 29, 2019, 6 p.m.
It was believed that after adolescence we were pretty much stuck with the brain cells that have already been formed, recent studies have shown that neurogenesis can occur well into adulthood.
University of Illinois research has found that though at a decelerated rate brain cells can form well into the 90s, even if one has cognitive decline and Alzheimer’s disease, as published in the journal Cell Stem Cell.
Postmortem brains of people between the ages of 79-99, some of whom had cognitive decline or AD, were examined targeting neuroblasts and immature neurons in the hippocampus area; those who had died without cognitive problems had proliferation of both kinds of cells in their brains, and those with cognitive decline and AD had evidence of the cells at lower numbers.
"We found that there was active neurogenesis in the hippocampus of older adults well into their 90s. The interesting thing is that we also saw some new neurons in the brains of people with Alzheimer's disease and cognitive impairment." says Orly Lazarov.
Those who had scored higher on cognition testing late in their lives were found to have had more neuroblasts in their hippocampi, this was independent of level of degeneration visible in the brain.
"In brains from people with no cognitive decline who scored well on tests of cognitive function, these people tended to have higher levels of new neural development at the time of their death, regardless of their level of pathology. The mix of the effects of pathology and neurogenesis is complex and we don't understand exactly how the two interconnect, but there is clearly a lot of variation from individual to individual."
"The fact that we found that neural stem cells and new neurons are present in the hippocampus of older adults means that if we can find a way to enhance neurogenesis, through a small molecule, for example, we may be able to slow or prevent cognitive decline in older adults, especially when it starts, which is when interventions can be most effective."
Since a person’s level of plaques and tangles does not always correlate with cognitive and behavioral symptoms these findings may help to explain why this disconnect exists; maybe neurogenesis matters as much/more than the amount of plaques and tangles that develop, if true then scientists can study how we can harness this for therapeutic reasons.
More research is needed to gain better understandings, but preventing cognitive decline and dementia is most likely the best route. This study also ties in on a positive matter with other studies on neurogenesis, that lifestyle habits such as exercise have been consistently shown to boost neurogenesis. Based on these findings participating in regular exercise and other brain healthy habits now and for as much of your life as possible will go along way to keeping your brain happy and healthy.
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