You Can't Rewire Your Brain! Oh, Yes You Can...Kind Of!

A bunch of new research shows the limits of the brain in rewiring, but at the same time how it can compensate for lost functions, and some functions may indeed be able to be restored.

Yes, the title may sound contradictory and it was stimulated by two neuroscientists from Cambridge University and John Hopkins University who have just published a paper arguing against the brain being able to rewire itself. This brain rewiring is a common theme of motivational speakers, ahem including people like myself!

However, to my credit at least, I have also argued for the limitations of said rewiring, understanding a thing or two about the brain, as I do. That said, that message does fall flat I notice, people really do want to hear that the brain is capable of magical things, it is, but alas a dose of realism is also needed.

But on the other hand other research has just come out pointing to what seems like the opposite: one group of researchers managed to measure brain activity before and after the removal of a language processing hub - a first, and gives us extremely useful insight into how the brain tries, immediately to reorganise processing. Another seemingly contradictory piece looks at restoring brain function after stroke - that would be a godsend.

So let’s explore what these researchers are saying, or have shown, and how much your brain can or can’t rewire then.

Your brain can rewire - locally

Let’s start with the good news first. These researchers are not arguing against what is known as Long-Term Potentiation (LTP). This is the process by which new connections between brain cells are developed - this has been extremely well documented. This bit of good news stays the same - your neurons are in a constant state of flux growing and shrinking connections between cells and activating or deactivating them. It may not be as dramatic as it sounds - many functions remain very static, or are slow to change, but change they do.

The problem is that when we speak of growing brain connections many of our imaginations run away with us. We imagine our brain cells reaching out and growing and connecting across the brain in multiple ways. That’s not how it works - these connections are connections that sit very close to each other. There is no documented growth of connection between more distant brain regions. Cells sitting next to each other can therefore build new connections and strengthen their signalling. That’s it.

But that is indeed magical for those that still think that our brains are static organs - but this plasticity does have its limitations.

We have probably also all heard stories about, for example, blind people and how their brains reorganise and use their visual centres to process sound or touch. Their brains appear to rewire and adapt to a life without vision. It sounds magnificent, but is this really the case? It is precisely this that Tamar Makin of Cambridge University and John Krakauer of John Hopkins are arguing against.

Brain reorganisation

They are obviously not arguing against the brain adapting, sometimes magnificently, to many of these changes but to how we describe or should describe the process. As an example Tamar Makin simulated an experiment of finger amputation. The standard way of thinking is that the function of each finger can be mapped to a specific brain region with each finger having it’s own dedicated area. The size of this region also implies the importance of this region for us - so for example the hands take up a lot of processing power as do our tongues.

(body size according to size of brain region associated with that body part)

So when a finger is amputated, or lost, the standard thinking is that the region associated with that finger is reassigned, or rewired to take over functions of other fingers. But Makin showed that this is not the case. In the experiment that she conducted, using a nerve blocker it should be noted, scientists don’t go around randomly cutting off people’s fingers, thankfully, she notes that the brain regions for the fingers have representations of all the fingers but are primarily, but not exclusively, assigned to a specific finger. So when this finger is removed, as they already have representations of all fingers, the regions can then refocus. This is not a rewiring - it is adaption of a current ability, often latent.

Your facial recognition area is more refined than you think

Another interesting example is that of an area called the fusiform face area. This is a small region in the brain which is associated with facial identification - one famous piece of research showed that this area seems to hold specific representations of specific people. The piece of research showed a specific activation to the face of famous actress of Friends fame, Jennifer Aniston.

And Paula Plaza et al. of the Georgetown University Medical Center have also just published a paper that confirms Makin and Krakauer’s proposal of functional reorganisation of latent abilities. In this they show that blind people who can identify faces through sound do so by using the fusiform face area (FFA) - but rather than thinking of the FFA as a visual system they note that the FFA seems to hold the geometry of the face but this can be activated by any input channel:
“Our study demonstrates that the fusiform face area encodes the 'concept' of a face regardless of input channel, or the visual experience, which is an important discovery.”

What happens when you lose a brain region?