Text written in Basque and translated automatically by Elia without any subsequent editing. SEE ORIGINAL

What is the brain?

Today we’re going to talk about how we can do a few seemingly simple things... like thinking. We start the session with a question as simple as it is broad: what is the brain?

The human brain is the site that controls the central nervous system, the site that controls almost all the activity of the body. It controls some of the activities without you noticing; for example, the rhythm of the heartbeat, breathing, and digestion. But we engage in the most complex activities: thinking and reasoning, for example.

In the simplest animals, the brain is also simple; the tasks of the brain are to control the body's metabolism and respond to the senses. In vertebrates, however, the brain is more important.

In amphibians, birds, or small mammals, the brain is smooth. But as the evolution of mammals progresses, furrows appear in the brain. In fact, the outer layer of the brain grows a lot and has no choice but to wrinkle it if the mind is not going to grow tremendously. This layer is known as the cortex and has to do with both the mind and cognitive abilities; thinking, memory, speaking, etc. The human being is the animal that has developed the cortex the most.

One fact to realize the importance of the brain: it is the only organ that is completely protected by a bone structure.

The brain is an off-white organ that weighs about 1.4 kilos: 1.5% to 2% of the body. However, it always consumes 20% of the energy of the body, regardless of the activity that is carried out. it has about 20 billion neurons, each of which can have thousands of connections to so many other neurons.

these EUR 20 billion represent only 10% of the total brain, but they are indispensable because their activity is based on the activity of the brain.

When a neuron is excited, an electrical impulse or current is generated within it. The impulse travels to the end of the neuron, where it causes the release of some chemical molecules.

These molecules, in turn, will excite the next neuron and produce another electrical impulse. And so, from neuron to
neuron. This communication between neurons and chemical molecules, neurotransmitters, is called synapses. Adrenaline, such as serotonin or dopamine, are neurotransmitters.

The information that the brain receives, generates and sends is in the flow of electrical impulses and neurotransmitters, so when they do not work well, errors, diseases arise. For example, if the neuron loses the protective layer around it, it does not conduct electricity and Alzheimer’s develops. Or if there is not enough serotonin, the synapse does not occur properly and depression may occur.

In terms of functioning, we also know that many functions are located in specific parts of the brain. Because of this, it is often seen that the brain is represented by
functions. This is not new, but we now know that the boundaries of sites and functions are less precise. Thus, when some task requires a lot of effort, more neurons belonging to this function are put to work in it.

Not just that. It can happen that, if some part of the brain is damaged, the neurons of another part take over the role of the damaged one. This brings us to the plasticity of the brain. That is, the brain is constantly forming new connections and circuits to adapt to new needs. It's not a closed-circuit, rigid organ.

The brain is considered an organ, but it is also paired with the muscles, and it is said that to have a clear mind it is necessary to train it. See how different brain activity is if you don’t listen to Dvorac’s 9th symphony from someone who doesn’t know anything about music and a violinist. The untrained person only activates the environment of the ear, while the violinist activates, in addition to the ear, those related to pleasure
and those of memory, able to resist the music.