Today I want to talk about another topic that greatly interests me: neuroscience, or the study of the brain and the neurons. The brain is often considered the most important organ in our body, and the reason why we are human in the first place. However, I still read a lot of misconceptions about the brain nowadays. Therefore, today I will address several of these misconceptions in the hopes of bringing a better understanding of the brain.

1. We only use about 10% of our brain

This is maybe one of the most common misconception I hear, and unfortunately it is widely believed. Oftentimes, movies will expand this misconception by saying that if we were to use 100% of our brain, we would be supernatural creatures. Unfortunately, using 100% of your brain will not grant you access to superpowers, because you are already using all of your brain. We are able to image your brain (using MRI or PET) in real time, which tells us which parts of the brain are used. And in doing so, scientists have seen that the entire brain is used, but not all at the same time. For instance, moving your fingers will use a part of the brain, while speaking uses a different one. Many scientist have managed to map the brain and nowadays we know how every part of the brain influences our behaviour. As a conclusion, you are using all of your brain, just not all at the same time [source / source / source / source / source].

2. Left brain vs. right brain

We often hear that some people have a more dominant left or right brain, or that the left part of the brain is logical and the right one artistic. While we do not know where this myth arose, we know that it is not entirely true. The brain is composed of two hemispheres, left and right, and these two are connected via what is called the corpus callosum. in theory, the left and right hemispheres are identical in structure, and both hemisphere are able to do the same thing. There are however some asymmetry in the brain. The most known one is speech comprehension and production, made by the Wernicke and Broca’s area respectively. These two area of the brain are found only on the left hemisphere and not the right one. Other asymmetrical behaviours include vision or face recognition but in reality, most behaviours use both hemispheres. Further, a specific study wanted to see if people had a dominant hemisphere. To do so, they imaged the brain of many people and looked at which hemisphere was more used. The results showed that there was no hemisphere dominance in any subject. Therefore, we can conclude that some of our actions will trigger one hemisphere preferably over the other, but people do not have a dominant hemisphere [source / source / source / source / source / source].

3. Damage in the brain is permanent

We have all heard that once a neuron dies, it cannot be replaced. While brain damage is extremely dangerous, the brain is surprisingly very good at repairing itself. First, it can make more neurons. This is a process called neurogenesis, and it has been extensively studied, and they have shown that neurogenesis occurs throughout the life of humans, showing that if a neuron dies, it can be replaced. However, sometimes simply replacing a neuron is not enough. In this case, the brain can recruit other parts of the brain to do the jobs of the damaged part. This is a process called plasticity, which means that a neuron is able to modify its function based on its environment. We will talk about plasticity in more detail in later articles, but this process is essential for learning and memory, as well as surviving dangerous brain damage. In conclusion, the brain is able to replace neurons and modify its function, making brain damage not so permanent [source / source / source / source / source].

4. The brain controls everything

This one is not so much a misconception as it is an incomplete information. We often say that the brain is the organ that controls absolutely everything in our body. Well technically that is not true. Proteins function without the brain saying anything, or the cell will multiply by themselves for example. The brain is usually responsible for any cognition, and control organs to make sure that they are working properly. However, there is the complicated topic of movement. It is technically untrue to say that the brain controls our movement, we would rather say that the nervous system controls it. The nervous system is composed of two divisions: the central nervous system (CNS), which comprises the brain and the spinal cord, and the peripheral nervous system (PNS), which is made of all the nervous structure outside of the brain and the spinal cord. In most cases, the brain will initiate any movement that we do, but there are instances where it does not. The main one are the reflexes. Let’s say you are touching something very hot. Under normal conditions, the PNS will indicate to the spinal cord that something is hot, and the spinal cord will tell it to the brain. The brain will then decide to move the hand, and the information goes down the spinal cord onto the hand. This mechanism is too slow and could result in the hand being damaged. To prevent that, we have reflexes: if you touch something hot, the PNS will inform the spinal cord, which will first make the hand move, and then tell the brain what happened. Therefore in this instance, the movement was initiated without the brain input. There are other instances where the brain is not needed for movement: the PNS is mostly responsible for bowel movement, usually without the brain input. In general, the brain does not control everything. However, it CAN control everything, because it is the decision center, and will modify our body function if it believes it is needed [source / source / source].