Myth debunked: Proof that we do grow brain cells as we age

Scientists behind the new study believe the necessity to keep learning new things even into old age creates a demand for new neurons. Photo / 123RF

Humans continue creating new brain cells throughout their life, scientists have proved for the first time.

Analysis of the anatomy of 58 people who died between the ages of 43 and 97 found evidence of "neurogenesis" in even the oldest.

The findings are significant because for decades many experts believed that humans are born with all the brain cells they ever have.

However, the scientists behind the new study believe the necessity to keep learning new things even into old age creates a demand for new neurons.

The study may also prove a crucial fresh starting point in the so-far fruitless hunt for an Alzheimer's cure.

The team found that the number of new brain cells tailed off with age across all the brains they studied - between the ages of 40 and 70, the number of fresh neurons spotted in the part of the brain studied fell from about 40,000 to 30,000 per cubic millimetre.

However, in participants in the early stages of Alzheimer's they fell dramatically, the number of new neurons forming falling from 30,000 to 20,000.

This occurred earlier than the accumulation of amyloid beta, which has been one of a major focus of drug development. Only last week a major trial which aimed to remove amyloid from the brain was abandoned.

Dr Maria Llorens-Martin, senior author on the study at the Autonomous University of Madrid, said: "This is very important for the Alzheimer's disease field because the number of cells you detect in healthy subjects is always higher than the number detected in Alzheimer's disease patients, regardless of their age.

"It suggests that some independent mechanism, different from physiological ageing, might drive this decreasing number of new neurons."

She added: "I believe we would be generating new neurons as long as we need to learn new things. And that occurs during every single second of our life."

The study is published in Nature Medicine.