Adulthood may not be the end of brain growth

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You may have heard that the brain doesn’t fully develop until after the age of 21 and that, to a certain extent, our brains are unable to grow past that stage – that may not be true after all, with a 2005 study putting that old adage in question. Tests on mice have revealed that their brains were able to react, adapt and change their structures by both shrinking and expanding.

The experiments were carried out at the Massachusetts Institute of Technology (MIT), and showed that there was the potential for brain growth in adulthood. Whilst the results showed relatively small growth changes when compared to pre-adulthood, study co-author and MIT neuroscientist Elly Nevidi points out that any brain growth at all is fairly incredible:

“The scale of change is much smaller than what goes on during the critical period of development, but the fact that it goes on at all is earth-shattering.”

“A signal propagating down an axon to the cell body and dendrites of the next cell” source; wikimedia.org; author; US National Institutes of Health

As the study lays out, they were able to prove that dendrites were still physically malleable with growth recorded in short bursts – with one subject almost doubling the length of a dendrite in the space of two weeks. Overall, the authors of the paper concluded that although there was no physical modification of pyramidal neurons, about 14% a group of inhibitory neurons called interneurons they observed during their experiment showed some form of modification.

To put that in perspective, it is estimated that for several years after birth, our brains manufacture over 250,000 neurons per minute, and spend an additional amount of time to wire all the connections together. It had been assumed within the scientific community that after the initial growth our brains were incapable of increasing in size – no matter how small.

That being said, prior to this study, it had already been widely accepted that external factors such as an accident, health complications or certain habits could affect brain capacity and neural pathways, therefore impairing our brains’ ability to work effectively. The potential for additional growth however, had never been considered, as the scientific community had assumed that brain plasticity was reserved to the developmental phase. But does this discovery alter anything major?

Unfortunately, since the original publication in 2005, there has been little done to build upon the research. Although the findings were indeed ‘earth-shattering’, there remains little use for this knowledge outside of consolidating our knowledge of the human brain and its various intricacies.