Hierarchical brain

Your brain is made up of many billions of special nerve cells; each has joins from and to many hundreds of others, making trillions of joins altogether.

The nerve cells in your brain are very much the same as all the other cells in your body but they can also handle messages.
- The messages are passed between the nerve cells using the trillions of joins.
- Many millions of messages are being sent and received every second of your life, even when you are asleep.
- Each one of these messages is actually a tiny amount of electricity, always of exactly the same size.
- Each one is like a signal, or a bit of information, that goes from one cell to many others.
The signals come into the nerve cells in your brain from a number of different places.
- Your sense organs, such as your eyes, ears, nose, tongue and skin have special cells that change the information they receive into electrical signals for the brain.
- For example, your eyes change light waves into electrical signals, and your ears convert sound waves into electrical signals.
- Signals also come into the brain from other places in your body, such as your muscles, and internal organs like your heart and gut.
- These signals are also changed into electrical signals so that the brain can deal with them.
Signals go out of your brain to all the different parts of your body.
- Nearly all the muscles in your body move because of electrical signals from the brain.
- All the signals are just the same tiny amount of electricity, so the amount that a muscle moves only depends of the number of signals it receives in a short time.
- Some muscles in your body work on their own, but signals from the brain can change their behaviour.
- For example, your heart beats on its own, but signals from the brain can change how fast your heart beats.
Inside your brain, nerve cells not only receive signals when they arrive from outside the brain, but all the time they also receive signals from other nerve cells and send signals to other nerve cells.
- Each cell has many hundreds of joins to receive electrical signals from other cells and many more joins to be able to send an electrical signal to many other cells.
- New joins can be made, old ones can be removed, and existing ones can change in strength, depending on how much they are used.
- A cell uses all the signals it receives to decide whether to pass a signal on to many other cells.
- The decision that it makes is based on the total amount of electricity from all the signals it receives at any one time.
Chemicals in your brain outside the nerve cells can change the way that cells make their decisions and their joins.
- These chemicals are produced by cells in the brain, but also come from other areas of your body, such as from your stomach when you feel hungry.
- When you feel sleepy, it is chemicals in the brain that make some cells work much more slowly.
- When you are fully asleep it is chemicals in the brain that stop some signals being sent.
- When you are excited, it is chemicals in the brain that make more signals be sent in some areas.

Patterns are made in your brain by lots of nerve cells joined together in a group. Amazingly, it is these patterns that create all your thoughts, memories, intelligence, desires and dreams. Even more amazingly, these patterns also create you!

The patterns come about because joins can change their strength depending on their how much they are used.
- The patterns made by the joins change depending on the signals that are sent and received.
- Joins are made stronger if they are used a lot, or weaker if they are not used much.
- The patterns are like a copy in your brain of the signals that come in to your brain.
- All the patterns together become a model of things in the world, things in your body, and things in your brain.
Ever since you were a tiny child, even before you were born, these joins and patterns were being made and changed as you learnt things.
- You learnt things about your own body, such as how your arms and legs moved and how your brain could control them.
- You learnt things about the world around you, that a table is flat, that a frisbee is round, and that trees are tall.
- You learnt things about your own brain, such as how you could think about one thing at a time, and how you could decide what to do, but you didn’t know that you did these things by changing the patterns in your brain.
- And you learnt that there were other humans, like you, who also had brains and who could learn things, but you didn’t know that they did this by changing the patterns in their own brains.
As you learnt, the patterns in your brain came to stand for (to represent) all the things you learnt.
- You have a particular pattern in your brain that stands for a table that you use whenever you see, use or think about a table.
- You have another pattern in your brain that stands for a frisbee that you use whenever you see, throw, or think about a frisbee.
- You have a pattern in your brain that stands for your left arm, and links to it change every time you move your arm so that you know where your arm is.
- You have a pattern in your brain that stands for you thinking about something, and you use it to know that you are thinking about something.
Your learning never stops, so the changing of the patterns never stops, it is happening right now as you read or hear these words.
- Everything you do, say, think, dream or remember is caused by changes in these patterns, making new joins, changing old ones or removing unused ones.
- When you learn a song, it is made up of patterns in your brain.
- When you learn words, they are also patterns that stand for other things in your brain.
- Sleep is very important in helping you learn and remember things for longer, and dreams are probably caused by this happening.
All the patterns together make a model of everything you know, and they also make you.
- Your model includes your own body so that you can run, jump or put your hand on your head.
- Your model includes everything outside your body so that you can pick up a ball, put a cup on a table or throw a frisbee.
- Your model also includes your own brain and how it works, but this part takes some time to be made, so was not properly working until you were three or four years old.
- What you think of as “you” is actually a model of your brain and your body inside your brain.

Your brain makes a model of everything, the outside world, your body and your brain; “you” are part of that model, and everything you know is only from that model. That is why everything you think you know is not quite as it really is.

You may think you see colours, but in fact different colours are just different shapes of waves of light.
- Your brain has learnt a pattern for each of the different shapes of light waves, and your model knows them as different colours.
You may think you hear sounds and music, but in fact sounds are just different sizes and shapes of waves in the air.
- Your brain has learnt many patterns for different sizes and shapes of air waves, and your model knows them as different sounds that sometimes come together to make music.
You may think you can see and hear new things, but in fact you can only recognise things once you know what they are.
- Your brain has to make the pattern first, and only then can your model know what the thing is.
You may think that you always decide exactly what to do, what to say, or what to think, but in fact these things are often decided by your brain before “you” find out about them.
- A lot of clever things have to be done by your brain very quickly, too quickly for “you” to decide, and sometimes you only find out about them a short time later.
- Your brain does this by predicting what might happen next before it happens.
- This is how you can catch a ball, ride a bicycle, or play a musical instrument. If you had to think about everything you did in advance all the time, you would never be able to do these things properly.
New skills or behaviours always have to be learnt first before they can become automatic.
- When you are learning to ride a bicycle, you first have to think about what you are doing, and you will sometimes fall off, but with practice it starts to become automatic, and then “you” can do it without “you” doing any thinking.
- In exactly the same way, when it comes to behaviour you want to pursue, whether it is adopting good habits or abandoning bad ones, you need to think about what you do to start with, and after practising for a time it will become much more automatic.
- It is always possible for you to make a difference to how your brain decides things because you can largely control what you do and what you say, and even what you think, if you think about it first.
- Sleep is very important for thinking and learning, you cannot do these so well if you are tired; and sleep also helps store what you have learnt and the things you want to remember.

Feelings, such as happiness and sadness, emotions such as anger, fear and love, as well as pain, are all patterns made in your brain.

When you have these feelings or emotions, the patterns that stand for them are joined to the pattern that stands for you, the model of you, so for a short time they seem as though they are part of you, which is why they feel like something.
The same is true for the meaning of something or a feeling about something. When you see or hear or think about something, the pattern that stands for that thing is joined to the model of you for a short time, so you can have a feeling about it, and you know the meaning of it.

Your brain is an amazingly complicated mixture of cells, electricity and chemicals.

We still do not fully understand how the brain does what it does, but we are making progress in explaining it.
What is most surprising is that at present we know far more about how the inside of a star works than how the inside of our head works.
It is what is inside our head that allows us to understand how a star works, but it is also what is inside our head that allows us to understand how the inside of our head works.

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