How do our brains change?

Lately, I’ve been spending some time on the weekends organizing my photographs from the last 28 years of backpacking. I came across these three photos of some of my campsites at various lean-tos.

The two were taken while hiking the Appalachian Trail in the 80’s and 90’s when I was in my teens and early twenties. The third was taken on my hike of the Long Trail this past summer. The first two are a mess: gear is spread out all over the place. In the third, my gear is much more consolidated and organized. I was struck by how my practices had changed over the years without my having noticed until now.

It was then that I realized something. Namely, the changes in the appearance of these campsites is a result of changes in my brain that have taken place over these many years. They happened so slowly and over a long period of time that I failed to notice they were happening.

It was then I decided to do some research and write a post about how our brains change throughout our lifetimes. This is a very big topic, so I decided to focus on three areas for this post: the prefrontal cortex, neuroplasticity, and aging.

The Prefrontal Cortex

Your prefrontal cortex is right behind your forehead and takes up about a tenth of your total brain. Its most important purpose is providing executive function. Executive function comprises such things as planning a grocery-shopping trip, packing for a vacation, organizing your gear, etc. Put another way, the prefrontal cortex supports `adulting’. In most individuals, the development of the prefrontal cortex primarily occurs during adolescence and is complete by age 25. However in neurodivergent individuals, such as autistics or those with ADHD, this part of the brain can develop more slowly. (When I look at those pictures, I wonder if what I am really looking at is the development of my prefrontal cortex). A sad incident that illustrates the role of this part of our brain is that of Phineas Gage, a railroad worker who in 1848 suffered a seemingly devastating head injury while packing gunpowder into a hole in a rock with an iron rod. This was done in preparation for blasting the rock to pieces for the sake of laying new track. The gunpowder exploded and sent the rod flying out of the hole and through Gage’s skull, damaging severely his prefrontal cortex. Incredibly, Gage survived. In the years after though, his friends and family observed that he had lost his ability to formulate plans and stick to them. There also is some testimony to indicate he become very impulsive.

Neuroplasticity

More recent research into Mr. Gage’s life has revealed that within four years of his accident, he had recovered much of his lost cognitive function and had found ways to cope with the remaining deficits. This has been an overlooked, yet very dramatic manifestation of another feature of our brain: neuroplasticity.

Put simply, as we learn, our brains change their physical structure. One of the most striking and famous demonstrations of this principle was performed by neuroscientist Eleanor Maquire of University College London. Dr. Maguire and her team studied the brain development of those seeking to become London cab drivers. These cabbies-in-training spend years memorizing the layout of London’s streets and must pass an exacting examination to earn their licenses. Dr. Maguire’s team found that their hippocampi, a part of the brain responsible for memory, grew significantly during the process. In other words, you didn’t have to be born with a large hippocampus to become a London cab driver, but you did have to put in the work to grow one.

Aging

Natural aging processes also affect the structure of our brains. During our first year of life, our grey matter undergoes an explosion of development. The rate of development drops off afterward. By age 25, most brain development is complete. Interestingly, the last part to develop is the prefrontal cortex, which develops in our teen years. Later in life, parts of our brains shrink in size, blood flow to the brain decreases, and inflammation may negatively affect brain function. In spite of all this, older adults can continue to learn new skills.

Maintaining brain health

As I age, I’m trying to learn more about how to keep my brain healthy. Diet, physical, and mental exercise can all positively affect our brain health. Interestingly, the foods that keep your heart healthy, such as salmon, green leafy vegetables, and berries, also help to keep your brain healthy. In fact, your coffee and tea not only give you a wake up but contribute to long-term brain health. At the same time, an afternoon ‘powernap’ also contributes to brain health. Exercise stimulates the release of brain-derived neurotropic factor (BDNF) which your brain uses to build new neural connections (i.e. create neuroplasticity). Engaging in cognitively-stimulating activities such as learning a new language also help to maintain good brain health.

Finally, I’ll give a plug for our favorite activity: backpacking. Backpacking certainly involves physical exercise. But I’ve always believed backpacking is at its heart a problem-solving activity. Almost every trip presents some obstacles to be overcome such as equipment failures, lost or forgotten items, trail closures, unexpected severe weather, etc. Longer trips require the design of resupply plans and possibly solutions of other logistical problems. Each of these challenges is an opportunity to engage our problem-solving skills and make our brains stronger for all aspects of our lives.