Learning Lab

The Brain Can Generate Completely New Brain Cells in Adulthood….or can it?

By Amy Brann

The brain can generate completely new brain cells in adulthood…or can it?

Neuroplasticity is a wonder of the brain.

It is the process by which you can learn new skills or improve existing ones. It allows you to build a bank of knowledge that can be flexibly updated every time you come across a new piece of information. And it enables you to shift your personality as you progress through adulthood and readily adapt to changing circumstances and environments.

That neuroplasticity takes places is undeniable. But there are different ways that this plasticity can manifest itself in the human brain. And that is where things, from a scientific perspective, start to become a bit murkier.

Because there are two main ways that your brain can potentially change over time.

Changing over time

One is by modifying the brain cells – the neurons – which already exist in your brain. They can grow or shrink. Build new connections or lose old ones. This is a process which is relatively well characterised (although the exact mechanisms are still updated from time to time).

The second is by generating completely new neurons. Ones that weren’t formed when your brain was developing either prenatally or during childhood (adulthood officially starts around 25 years old according to your brain).

And although it is generally thought that this so-called “neurogenesis” continues to take places in adulthood in humans, there is still evidence emerging which supports both the “for” and “against” arguments.

In the last month or so, there have been (at least) two such studies. One concluding that adults can’t grow new neurons in their brain. And another, a few weeks later, concluding the opposite – that adults can grow new neurons in their brain.

So which one is right? 

Getting the facts straight

Well, there is a belief in science that just because something is “absent” – in other words, that new brain cells weren’t found – doesn’t mean they don’t exist. It may just mean that the researchers haven’t been able to find them with their particular method and analysis technique. Similarly, some methods can generate misleading false positives.

But in general, just because some studies from time to time report a negative finding doesn’t mean that all the positive ones were wrong. It just means that the answer might not be as straightforward as the scientists once thought.

But that wouldn’t be surprising.

This is the human brain that we are talking about after all…

But why does this all matter?

Well, in one sense it doesn’t.

Because regardless of whether your brain is making new neurons when you are an adult, or not, your brain is still your brain. It still creates the thoughts, feeling and actions that you are necessary for your to perform on a day to day basis.

Where it might matter more, is when you have had damage to your brain from a concussion or a head injury, for example, if you have had an accident or played some forms of contact sport. Because knowing that your brain can grow new neurons to replace damaged ones is pretty fundamental from a recovery perspective.

Similarly, as you age, there is a gradual age-related decline at both a structural and functional level in your brain. Being able to grow new neurons to compensate and stave off some of this decline would be most welcome and could even hold the secret to therapies for neurodegeneration.

A science which never stands still

But the debate is also a reminder of how difficult it is to obtain concrete answers about the human brain. How much of a black box it still is. And how our understanding is continually evolving as imaging techniques allow scientists to look ever closer at the tiny neurons (and glia!) which underpin our thinking.

A debate like this also reminds us of a few more general points when it comes to our thinking:

  1. Overcoming the Need for closure. Many of us have a natural tendency to desire closure. A need to find the solution to a problem. To resolve a mental conflict. To work out the truth. But sometimes this just isn’t possible. The concrete answers aren’t available and the debate still very much alive.  Instead, the best you can settle on is a temporary staging post in your mind. A staging post which helps you obtain some degree of mental stability, whilst still leaving the door open for the next instalment. Being able to cope with this kind of uncertainty and instability in your thinking is essential for a healthy and productive mind.
  2. Creating a state of continual mental improvement. Our knowledge and skills never stand still. Nor should they. Because just as companies strive for continual improvement, so should you when it comes to your brain. Being open to change and novelty and not preferring always to stick with the status quo from fear of what you might find or discover enables this process of continual mental improvement. Because although familiarity offers comfort, novelty offers opportunity.
  3. Don’t become inflexible in your thinking. Sometimes when you become an expert in something, is causes you to become more rigid in your thinking (the so called Einstellung effect). It results in you displaying your expertise with a “my way is the right way” kind of mentality. But being inflexible in your thinking in a killer for creativity and problem solving. It can also cause you to hold onto something that you think is right for too long, when instead you should be updating your thinking. The antidote? Curiosity, and being on the lookout for information which advances and updates your knowledge, rather than only focusing on the information which reinforces your (potentially outdated) viewpoint.

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