Smart phones and tablets might be pretty nifty, but they have nothing on the human brain. That squishy ball inside your skull can store up to 100 million megabytes of data and is millions of times faster than any tablet. And let’s face it, scientists are a long way off from creating an app that controls everything from your breathing to your heartbeat while simultaneously helping you navigate your way through traffic and planning the day ahead.
If you have MS, then you probably know more about the inner workings of your brain than most people, but here’s a quick refresher, just in case…
Your brain began as a mass of cells known as the neural plate, just 16 days after conception. By 27 days, this tiny structure had folded in on itself to form the neural tube, which gradually transformed into your brain and spinal cord. By the time you were born, your brain consisted of around 100 billion neurons or nerve cells, which gradually extended branches (otherwise known as dendrites), to connect with other neurons and create a dense network of nerve cells responsible for all your thoughts, sensations, feelings and actions.
By age 15, your brain finally reached full size, weighing around three pounds (that’s 1.5 kg if you prefer the metric system) and – despite making up just 2% of your body weight – consuming around 20% of your total energy reserves. Thinking is hungry work! Your brain hasn’t stopped changing since – nor will it. We now know, for example, that the brain undergoes important changes during adolescence. Myelination (the formation of the fatty myelin sheath that surrounds and protects the nerve fibres) begins at the back of the brain and slowly works forward. This means the front of the brain – the region that houses the frontal and prefrontal cortices – is the last to be fully myelinated. These areas play an important role in insight, empathy and risk-taking, which might explain why even the brightest teenagers can do crazy things.
Fortunately, the frontal lobe is fully developed by your 20s when the brain reaches its peak performance. Unfortunately, reasoning, spatial skills and cognitive processing all begin to decline after this time. Your brain begins to lose volume, and the myelin sheath surrounding the nerves begins to break down, which means nerve impulses aren’t transmitted as quickly. In your 30s you begin to lose more and more brain cells, a gradual deterioration that continues throughout your 40s and 50s. In fact MRI scans in the general population reveal a gradual loss of brain volume at a rate of around 5% every 10 years after the age of 40 years.
A big part of this shrinkage as we get older is down to the loss of grey matter. But the incredible thing about the brain is that it can adapt to this loss by finding alternative neural pathways – a bit like taking a different route to avoid a traffic jam. This means that the effects of grey matter loss with age are mostly subtle. You might notice you become more forgetful as you get older or that you take longer to remember things, but this is all just part of the natural ageing process.
We now know that brain volume loss occurs three to five times faster in people with MS than in those who don’t have the condition. One of the reasons for this is that repeated attacks by the immune system thin and destroy the myelin, impairing the neuron’s ability to conduct electrical signals. Unfortunately, this means that when your grey matter does eventually start to decline with age, the impact on mental processing may be more noticeable because there’s less white matter to compensate.
Inflammation can also affect the brain as you get older. Again, this is the case for everybody, but is more marked if you have MS. That’s because the breakdown of myelin triggers other immune cells in the body to release inflammatory compounds such as cytokines and antibodies, which cause further inflammation in the central nervous system and can stop even healthy nerves from functioning properly.
Whether you have MS or not, the brain definitely becomes less efficient at retrieving information and storing new data as you get older, particularly in your 60s and beyond. That doesn’t mean we’re any less intelligent, though. Studies show that if given enough time to perform a task, the scores of people in their 70s and 80s are often similar to those of young adults. If you have MS, it may be that you simply need to make allowances for yourself, whether that’s giving yourself more time to achieve certain tasks, or factoring in more hours of sleep.
And it’s not all downhill. Sure, our brains get slower at processing information as we age, but they become stronger in other cognitive areas, such as vocabulary and general knowledge. Older definitely equals wiser, it seems.
In the meantime, regular exercise, a healthy well-balanced diet, plenty of sleep and being mentally active are all important ways to ensure your mind will stay sharp for a long time to come. That smartphone or tablet, on the other hand, will probably be obsolete in the next two years.