Nanogirl Dr Michelle Dickinson: Do we grow more brain cells as we age?

While scientists debate whether we grow new brain cells as we age, keep on challenging yourself with the crossword. Photo / 123RF

The hippocampus, the part our brain linked to learning, memory formation and emotional processing, has caused debate this week with two different research groups publishing similar research with opposing conclusions.

The scientific question asked whether or not human brains have the ability to grow new brains cells as we age. One study says no, the other study says yes, and both have the evidence to back it up.

The first paper, published in Nature last month, studied brain tissue from 59 people up to the age of 77 who had died or had their brain tissue removed during surgery for epilepsy.

The researchers used fluorescent antibodies to label proteins in specific cells and searched for the cells using a microscope. They were barely able to find any new neuron production in humans over the age of 13 and stated that there was undetectable new brain cell growth by late teenage years.

Their conclusion is that we can't make new brain cells as we age.

The second paper, published this week in Cell Stem Cell, studied brain tissue from the autopsies of 28 people aged 14-79 who had died suddenly and not been on medication.

They also used antibodies to stain specific proteins and used microscopes to view them.

Their conclusion was that older people have a similar ability to make thousands of hippocampal new neurons from progenitor cells as younger people do.

This is the fun thing about science and these two papers show how it is really difficult to conclusively prove some things.

It also shows why you should never draw a conclusion from just one research study, but look at the evidence from multiple sources.

The challenge here is how do you scientifically prove a negative? Can these researchers really prove that new neurons are actually missing from the adult brain, and be sure that they didn't just miss them?

The problem with using protein staining to study brain cells is that most brain tissue studied is either from patients who are dead, or brain tissue that has been removed from a living brain and stored.

This opens up the possibility that the proteins in question could degrade meaning they are not picked up during testing which can vary depending on how long the brain has been stored.

This question of whether and how new neurons are born in adults is important for researchers to understand how our brains adapt to changing life circumstances, which could help to develop insights into solutions for repairing brain injuries such as those caused during a stroke.

For the rest of us, these opposing studies probably won't affect our day to day lives. Even if we can grow new brain cells, the research showed that the brains of older individuals had fewer new blood vessels in this area of the brain, which could negatively affect the ability of these neurons to make connections with each other.

Our challenge is not about whether or not our brains are growing new cells but instead how we can keep our brains sharp for as long as possible.

Ageing happens to us all and as the scientists keep debating, the more relevant research indicates that older adults who devote at least an hour each day to a range of intellectually engaging hobbies such as bridge, board games and musical instruments were much less likely to develop dementia that those who didn't.

So as the scientists continue to battle it out, we can sit back and finish the crossword to help keep our brains as fit and healthy as we can for as long as we can.

Dr Michelle Dickinson, creator of Nanogirl, is a nanotechnologist who is passionate about getting Kiwis hooked on science and engineering. Tweet her your science questions @medickinson.