20 years ago, in a landmark article, researchers concluded that the human brain retains the potential for self-renewal throughout life.
Before this, scientists believed the adult brain was hard-wired and therefore not able to produce new cells.
While most neuroscientists accepted the new findings, there has been an ongoing debate about whether this renewal ability applies to the whole brain, and whether it declines or stops altogether in seniors.
Now, groundbreaking research reveals new cells are created in a key area of the brain to the same extent in someone in their 80th year as in a teenager, giving hope to all of us who want to retain our memories as we age.
Animals Lose Ability to Generate New Brain Cells
Maura Boldrini, associate professor of neurobiology at Columbia University, New York, together with her colleagues, studied the brains of 28 people aged between 14 and 79 shortly after death. None had been diagnosed with any neurological or psychological condition.
The researchers were interested in the hippocampus. As you probably know, this is a key region of the brain important for emotion, cognition and memory.
And in particular, they wanted to look at a part of the hippocampus called the dentate gyrus, which produces new neurons and helps form new memories from personal experiences and events in a person’s life.
They already knew from studies in rodents and non-human primates that with aging the ability to generate new cells in the hippocampus declines. Was this also true of humans?
Using various techniques, they examined the volume of cells, the number of cells in different stages of maturity, and the degree to which new blood vessels were being formed.
Young and Old Have Same Hippocampus Volume
Dr. Boldrini summed up their findings.
“We found that older people have a similar ability to make thousands of hippocampal new neurons…as younger people do. We also found equivalent volumes of the hippocampus across ages.
“The exciting part,” she added, “is that the neurons are there throughout a lifetime. It seems that indeed humans are different from mice – where [neuron production] goes down with age really fast – and this could mean that we need these neurons for our complex learning abilities and cognitive behavioral responses to emotions.”
Commenting on the study, Dr. Duncan Wood, a neuroscientist at the Open University in the UK, said these findings “provide further evidence that mental decay and decline is not the inevitable process many of us think it is. There is hope for us all in our twilight years.”
Keep Active, Keep Learning, Keep Socializing
However, it wasn’t all good news. New neurons in older brains were less able to make connections, there was less vascularization (blood vessel formation), and a smaller pool of progenitor cells. These are similar to stem cells but are more limited in the types of cell they can become and in their ability to self-renew.
Dr. Boldrini believes these factors have the potential to compromise our ability to think and our ability to navigate emotional ups and downs in old age.
Her advice will probably be familiar to readers of this newsletter: To maintain brain health, you need to exercise, keep learning new things, be socially active and eat healthy foods.
Dr. Wood agrees: “If you are not an active learner in old age and remain a couch potato, you will experience mental decline regardless of the number of new neurons your brain is producing.”