How does our brain work?
How do we think? How do we form memories? And how does our brain control the rest of our body?
Our brain contains billions of neurons, which are no more than specialized cells. We all have a large network of neurons in our brain. And these neurons possess an extremely important feature: they communicate with each other, they have great "conversations" with each other, so to speak. They do not communicate through words, but through electrical impulses.
Neurons have many ramifications, in resemblance to a tree. They have many "branches", called dendrites (similar to the branches of a tree), which are responsible for receiving information, and contain spines (like the leaves of a tree). The spines work as a kind of ears, because they are the ones that receive the incoming information from neighboring neurons. Neurons also have a "branch" called the axon (similar to the root of the metaphorical tree) that doesn’t have any spines, and is responsible for transmitting information.
When we think, what happens in our brain is that neurons communicate with each other. When we remember something, ie when we recall a memory, that also happens.
So what about the rest of our body?
For example, if you wave at someone, who instructed your arm to make that movement? Your neurons did. Because apart from having neurons in our brains, we also have networks of neurons that start from our brain, go along the spinal cord to the other parts of our body. So in order to move your arm, the neurons responsible for that do a kind of “pass the message”. So the first neuron, in the brain, “tells” his neighbour: “Tell the arm to move”, and the second neuron passes on the message, etc, until the message reaches the arm. Although the reality is a little more complex, this is the essence of what happens.
Unfortunately, it can happen that one or more of these neurons malfunction, degenerate, become "ill" and start losing their spines (the metaphorical leaves), for example. And in that case the “pass the message” becomes more of a Chinese whispers game. In this game, people form a circle, someone says a sentence in his neighbour’s ear, his neighbour passes it one to the next person, etc. Naturally, once the message reaches the end of the circle, the inicial sentence is completely altered, because if but one person misunderstands, the sentence starts changing. In case of our arm, it may not receive the correct message. It is something similar that happens, for example, in Parkinson’s Disease. That is why the patients start, among other symptoms, to lose motor control.