Here at brainmatters.nl, we love the brain and we hope to get you just as excited about this mysterious organ inside our heads. If you don't know much about the brain, this is a good place to start. Let's start at the beginning: How did the brain originate?

As with anything that develops, the growth of the brain begins with the most important parts. Namely, the parts that make sure we stay alive. As a fetus grows into a baby in 9 months, so does the brain. The brain initially develops from a neuronal tube, which after a few weeks grows into three different parts at its end. These are very conveniently called the hindbrain, midbrain and forebrain. The rest of that tube later becomes the spine, while the hind, mid and forebrain continue to develop.

After all, what does a baby need to stay alive? A heartbeat and breathing. That's not a mere luxury. The areas that control these functions develop first. That development happens as follows: The hindbrain develops in the myelencephalon (or medulla) and the metencephalon, which in turn develops in the cerebellum and the pons. Together, the pons, medulla and midbrain form the brainstem. And it is precisely this brainstem that regulates the heartbeat and breathing of the future baby. 

Well, now that the brain is up to the most essential tasks, it can continue to develop. Now it's the forebrain's turn. This develops into the telencephalon and diencephalon. The diencephalon turns into the thalamus, the structure that is particularly important for communication between brain parts and the hypothalamus, the structure that controls needs such as hunger, thirst, fight or flight and fatigue and sleep, among others. The telencephalon also develops from the forebrain. From this later develops the limbic system, responsible for emotions, and the basal ganglia, responsible for regulating movement. So now, very simply put, we have a fetus that is alive (has a heartbeat and breathing), has needs (sleep, hunger, thirst, etc.), and can respond to them (with emotions or movement). 

Now there is a large part of the brain that we have not yet discussed, namely the cortex. The cortex is what most people know as the brain, that squiggly structure on the outside of the brain. It also originated in the telencephalon and is divided into four parts called lobes: The frontal lobe, temporal lobe, parietal lobe and occipital lobe. Each part has specific functions associated with it, but it is important to note that most of the actions people perform involve multiple parts. The occipital lobe is used primarily for seeing, the temporal lobe for hearing, and the parietal lobe for sensing and spatial awareness. These parts ensure that our future human can perceive things around them.

The only thing missing is a kind of control system that ensures that we do not act like unguided projectiles reacting to every need (for example, that we do not go peeing in the street, or eat the entire birthday cake at a party). That's what we have the frontal lobe for. This is the most complex lobe and you could say that it distinguishes us from monkeys. This is because this lobe is involved in driving goal-directed behaviour including self-control, speech and memory. At birth, however, this lobe is not yet fully developed (this can also be seen in the behaviour of babies and children). The frontal lobe continues to develop until sometime in adolescence. Only then is the brain fully developed, which is exactly why you can only drive a car and drink alcohol when you are older.

This was a brief introduction to the brain, but there is much more to learn. So did you find this article interesting? And would you like to learn more about the different parts of the brain and the ways research is done? Then read our Brain Basics articles. 

Author: Loes Beckers
Illustrations: Pauline van Gils

Reference: Breedlove, S. M., and Watson, N. v (2013). Biological psychology: An introduction to behavioral, cognitive, and clinical neuroscience, 7th ed. Sunderland,  MA,  US: Sinauer Associates.