Until a few years ago, we were taught that our brain cells do not multiply, and that they are irreplaceable once they die. However, during the last quarter of the 20th century, a few scientists were discovering that some neurons do in fact multiply, but their research were ignored and funding subsequently withdrawn.
At the dawn of the 21st century, new research suggests that we produce neurons throughout our life. Now, scientists are able to tell the age of neurons born during adulthood with reasonable accuracy. Studying cells in the hippocampus, part of the brain responsible for memory and learning, scientists have found cells that are younger than the person, proving they are new. It’s called neurogenesis, and researchers estimate we make around 700 new brain cells a day. The problem is neurogenesis slows as we age, which may be the reason so many of us find it hard to remember things and potentially develop dementia or Parkinson’s.
Researchers from the University of Queensland found that a molecule produced by nerve cells called fracalkine can stimulate stem cells to produce new neurons. Fractalkine is produced when we exercise. The study found that old mice with dementia, which were made to exercise heavily started to perform memory tasks just as well as their much younger counterparts. They also lived for longer. “We already know that regular exercise is good for the brain – but it may be possible to deliver growth hormone molecules in the right way to stimulate cell production and reverse dementia,” says Professor Perry Bartlett, the director of the Queensland Brain Institute.
Readers Digest Asia, June 2014
Slightly more technical references here:
New Brain Cells Erase Old Memories
Neurons: Good News, Bad News