Part 1

The Brain Book

Introduction This book is a voyage around the inside of your head. We're going to explore what brains are made of, how they work, and how they make you who you are. Everything that you feel, see, hear, taste, and smell depends on messages travelling around your brain. Every move you make is controlled by your brain, and all your emotions– happiness and sadness; frustration and joy; fear and love– are created by your brain. All brains are similar but each one is unique. Some differences depend on information in the DNA we inherit from our parents, others are caused by our experiences and what we learn. Brains can absorb huge amounts of knowledge– I hope yours enjoys finding out about itself! Dr Liam Drew

What is a brain? The mysterious organ inside your head is called the brain. It is what makes you who you are. All of your thoughts, experiences, and feelings happen in the brain. Brain story Some people think that the brain is the most complex object in the Universe! In this book, we are going to learn about many things that scientists know about this amazing structure. Wrinkles The outside of the brain is wrinkled and folded, so it all fits inside the skull. Cranium The largest part of the skull is a hard, bony case that protects the brain from physical damage. Spinal cord This carries messages to and from the brain and body. WHY DO I NEED A BRAIN? Your brain allows you to move around and do many things. It helps you to remember things, to learn, to eat and drink, to stay safe, and to make friends. Brain areas Here is what it looks like if you slice a brain down the middle. The brain is made of many areas, which have different functions, but they all work together to make you, you! An adult's brain weighs around 1.5 kg (3 lb). Nervous system The brain gathers information from all of the senses and tells the body what to do. All of this communication happens along nerves, which run to and from the brain and throughout the body. What do you think?

What does a brain do? The brain is the control centre of your body. It gathers information about what's happening, processes this information, and then controls how your body responds. All brains work similarly, but the little differences make everyone unique. Sight The eyes take in visual information, such as a plane flying by outside. Hunger The brain gives you a feeling of hunger if you haven't eaten for a while. That's a lot to do! Gathering information Your eyes, ears, and other sense organs turn information from the outside world into signals that are sent to the brain. The brain also keeps track of what's going on inside your body. It can tell you whether you're hungry, thirsty, sleepy, or in pain. Controlling your body All your muscles are controlled by the brain. By moving different muscles, the brain can make you run, jump up in the air, or grab a pen to write. Hearing Your ears sense noises, such as the school bell. Processing information When you think, your brain combines useful new information with useful stored information. You make memories of the most important things that you experience, think, and do. Feelings Your feelings, such as excitement when playing a sport, are produced by the brain. Memory Your brain stores memories, such as a great beach holiday. Thinking Your brain does your thinking, such as working out a sum. Writing The brain coordinates the delicate movements you need to be able to write. Getting the body ready Your heart– a big muscle– may pump a little faster if you're asked a question in class. This is because the brain prepares you for action. Talking The muscles you use to talk are under the brain's control.

Map of the brain The brain is made up of many parts, each of which handles different tasks, such as understanding the words you read or the sounds you hear. Here's a map of the brain showing where these tasks happen. Look in here! Body temperature, hunger, thirst, and many other body functions are controlled by the hypothalamus. The amygdala controls our emotions and gives them meaning. Memories are made in a long, thin structure called the hippocampus. Looking inside There are many more brain regions beneath the cerebral cortex, which all have essential jobs. These include the limbic system, which controls our instincts, memories, and emotions. Cerebral cortex The cerebral cortex is the folded surface of the brain. It is divided into four "lobes" with slightly tricky names– the frontal, parietal, temporal, and occipital. Complex thoughts and activities are processed here. Everything is connected! The cerebral cortex is only 2.5 mm (0.1 in) thick.

Studying the brain Scientists who study the brain are called neuroscientists. They do many different things to unlock the brain's secrets, including using brain scanners and microscopes, and studying the effects of head injuries. How MRIs work MRI scanners use very powerful magnets and radio waves to create signals from the body, which are turned into images by a computer. Inside your head MRI scans create 3D maps of the brain. You can look at any slice you like– this one looks as if the person's brain was cut right down the middle. The working brain When a part of your brain becomes active, extra blood goes there. Scans can detect the oxygen in blood and therefore which brain regions are working when you do certain things. Neurons up-close Scientists use microscopes to look at samples of the brain or neurons they grow in the lab. These help us understand how they work. CASE STUDIES If someone injures a part of their brain, it may change how their mind works. This can tell us what different brain regions do. Music memory If the hippocampus is damaged, people can lose the ability to form memories of new experiences. Older memories and learned skills are remembered, though. Taking sides Certain types of brain damage make people unable to see and respond to half of the world in front of them. They might only see half the food on a plate. Who's that? One part of the cerebral cortex responds to faces– damage to it leaves people unable to recognize anyone, even family and friends.