As you’re sat reading this, over a billion brain cells are ready to act on your every need and whim. The average human brain weighs about 3 pounds, which is more than the weight of all of your skin put together. Brains are made up of around 75% water and contain over 100,000 miles of blood vessels. Despite having so many neurons, nerves and electrical signals, your brain doesn’t have any pain receptors and therefore it can’t feel pain.
Although our brains are incredibly adaptable, it’s a myth that it can handle more than 2 conscious tasks at any one time. And having a bigger brain doesn’t always mean that you’re any smarter. Scientists have found that human brains were actually larger when we were ‘cave men’ but, as language and memory functions increased, these areas became more condensed. However, Albert Einstein’s brain showed that his parietal lobes (which are linked to ability in mathematics) were 15% wider than in people with normal abilities. That said though, his brain was overall slightly smaller than average.
This incredibly complex organ is really hungry too. Did you know that your brain will use 20% of the total oxygen in your body and if it is starved of blood for even 8 - 10 seconds you’ll pass out? You’ll only be able to survive for about 4-6 minutes without oxygen before the brain begins to die. If you don’t receive oxygen for 5-10 minutes your brain will be permanently damaged.
But what about those cases you hear of a person falling into very cold water and surviving prolonged submersion? First of all, a full recovery of such an incident isn’t as common as you may have heard and in nearly all cases the casualties tend to be either children under the age of 12 or of people who are quite small in stature. Scientists are confused about such events - the longest period of time that someone has survived underneath ice cold water, and made a full recovery, is 66 minutes. The current theory is that when these people fall into the water they breathe it into and out of their lungs. This would be a normal ‘cold shock response’ caused by uncontrollable hyperventilation and, in theory, this leads to drowning. However, the excessively cold water cools the heart which in turn cools the blood supply to the brain. The extreme and sudden cold is possibly enough to ‘freeze’ the brain and protect it from oxygen starvation. In order for this to happen the water needs to be colder than 6 degrees. Scientists in the UK, at Portsmouth University, have an extreme environments laboratory where they can experience temperatures from -20 degrees to 50 degrees C and study the effects of cold shock response as well as superficial cooling and its effects on manual dexterity.
When functioning properly and whilst you’re awake, your brain will generate the equivalent energy to power a light bulb (around 10 - 23 watts of power). You use all parts of your brain and not just 10% as is often cited. However, it is easily affected by chemicals found in drugs and, nowadays, in our food. A study in New York found that students who ate a lunch that didn’t contain artificial flavours, preservatives or dyes, performed 14% better than those who had these chemicals in their food.
Use it or Lose it!
Performing mental tasks really does strengthen the connections between your brain cells. Exercise also helps to maintain a healthy brain. Even memories, or new thoughts, can create new connections with the most powerful being conjured up by a scent. Nostalgia really is the most addictive drug! And if you’ve ever wondered, it doesn’t matter what you do, you can’t tickle yourself. Your brain won’t be fooled by your own touch and needs unexpected external stimulus to experience a tickling sensation.
When we talk about using our ‘gray matter’, we are identifying the color of all the neuron cell bodies in the outer layer of the brain. White matter is the nerve fibres that are coated with myelin sheath which allows them to send messages faster. Even though it’s only about 2% of your body weight, your brain uses 25% of your energy and it remains incredibly active even when we’re asleep. In fact, studies have shown that brain waves are more active whilst we’re dreaming than when we’re awake.
The classic walnut shape of the brain, that we’ve become familiar with, is made from folds that have helped us to evolve. During our evolution our forebrain grew larger as our cerebral cortex increased in size. The folds are simply nature’s easy solution to fitting more into the same space.
We remain fascinated by the capabilities of the brain and how it ages and responds to disease. With little ability to regenerate, diseases such as Parkinson’s and Alzheimer’s cause significant and irreversible damage as they kill brain cells. Illnesses like schizophrenia and depression are caused by more subtle changes and may possibly be caused by chemical reactions but our understanding of this area of epidemiology is still vague.
Using the unconscious part of our brain to aid learning may be a way we can excel in learning. Professional musicians, for example, spend hours practicing and, whilst they do, they store these repetitive patterns at the back of the brain, in the cerebellum (literally ‘the little brain). According to Neuroscientist Professor Anil Seth, of Sussex University, this is where there are more brain cells than the rest of the brain put together. The fluid movements needed to play a difficult piece of music are moved from the cortical areas, which are used when learning something new and tricky, to the cerebellum, which is where fluent, unconscious behaviour is produced.
Which area of the brain are you most interested in?