The brain can be described in four parts: the reptile brain, the limbic system, cortex, and prefrontal cortex. All four parts are interconnected networks of neurons or brain-cells that communicate by sending little packages of molecules between one-another, the so-called neuro-transmitters.
The reptile brain is the core of our brain and our spine. It is the part of our brain that keeps us alive and allows us to breathe, digest food, sleep, move our limbs etc. Some basic or “lower” emotions such as fear, hunger and sex drive also come from this part of the brain, as do our reflexes. Like all other mammals, we share this brain-structure with fish, birds and reptiles, hence the name.
The limbic system consists of a number of brain areas around the reptile brain and create our “higher” emotions such as empathy, love, shame, hope, joy, sadness, pride, etc. We share the limbic system with all mammals, but ours is the most complex by far and so are our emotions.
Around the limbic system, we find the cortex, the folded outer part, which takes care of learning, memory and most of what we perceive as thinking and decision-making. Different parts of the cortex solve different tasks, and we find here the mirror-neurons that allow us to read the body language and facial expressions of others. We also share the cortex with all mammals and, again, ours is the most complex by far.
It is the cortex that allows us to know what, say, a hammer is and constructs the concept of a hammer for us. If you think of a hammer right now, different parts of your cortex are working together to create in your mind the image of a hammer. Depending on whether you are right-handed or left-handed, the corresponding hand-related part of your brain is active too, as is your emotions concerning hammers, i.e. neurons in your limbic system and the reptile brain. If you are the DIY kind of person, you probably feel a little sense of joy thinking about the hammer, if you are the clumsy type with ten thumbs, you may feel a slight discomfort. This is your cortex, limbic system and reptile brain working together, telling you either “Yesss, tools! :-D” or “Uak! I’m gonna hurt myself and ruin something! :-o”
The prefrontal cortex is the part of the cortex right above our eyes. It generates our sense of time, logical thinking, planning, language, and the rest of our “higher” cognitive skills. It is the prefrontal cortex that allows us to play an instrument, compose music, read and write, imagine, create poetry, be religious, have moral values, and to postpone pleasant things and take up unpleasant endeavors instead. The prefrontal cortex allows us self-awareness and self-control. All mammals have some prefrontal cortex but it may be only rudimentary, such as in rodents. With larger mammals such as cats, tigers, dogs, horses, and elephants, there is a bit more of it, and in primates, it is noticeable. But the human prefrontal cortex is way bigger and more complex than the prefrontal cortex of any other species. The prefrontal cortex allows us to decide that even if we dread handling that hammer, those nails do not drive themselves into the wall so we can put a mirror there, and therefore: “I better get up and fix it. Hrmpf!”
In order for us to become emotionally, mentally and intellectually healthy and rounded persons, and in order to develop a maturity of mind suiting our age and the surrounding society, all parts of our brain must function, interconnect and evolve, as must our relationships, education and Bildung. What we experience and how we deal with it, literally shapes the physical structure and connections of our brain over time.