How does your brain work?

How does your brain work?

Your brain is the hub of your nervous system. It is made up of 100 billion nerve cells - about the same as the number of trees in the Amazon rainforest. Each cell is connected to around 10,000 others. So the total number of connections in your brain is the same as the number of leaves in the rainforest - about 1000 trillion.

How does your nervous system work?

The nervous system is a network of cells called neurons which transmit information in the form of electrical signals. Your brain has around 100 billion neurons, and each communicates with thousands of others – as many connections as in the world's telephone system, the biggest machine on the planet. Neurons communicate with each other at special junctions where chemicals help to bridge the gap between one neuron and the next.

What does the central nervous system do?

Your spinal cord receives information from the skin, joints and muscles of your body. It also carries the nerves that control all your movements. Your brain is the most complicated part of your nervous system. It receives information directly from your ears, eyes, nose and mouth, as well as from the rest of your body via the spinal cord. It uses this information to help you react, remember, think and plan, and then sends out the appropriate instructions to your body.

What makes the human brain unique?

During human evolution, our forebrain became larger as our cerebral cortex increased in size. This means it had to become more folded to fit inside the skull. This gives the outside of the human brain its 'walnut' appearance. Humans have a larger cerebral cortex relative to the rest of the brain than any other animal. The cerebral cortex handles many of our unique skills, like language and problem solving.

A brain of two halves?

The right side (hemisphere) of your brain controls the left side of your body, and the left hemisphere controls the right side. Although the two sides of the brain look like mirror images of each other, they are different. In most people, the left hemisphere is important for language, maths and reasoning, whereas the right is more important for emotion, recognising faces and music.

Left- or right-handed?

Are you left- or right-handed? Nine out of ten people prefer their right hand, which is controlled by the left side of the brain. As this side also usually deals with language, scientists have long wondered whether the two are linked. Apparently they are not - although right-handed people use the left side of their brain for language, so do most left-handed people.

What happens to a divided brain?

The left and right brain hemispheres share information through the nerves that join them. In some epilepsy patients these nerves are cut to relieve their symptoms. Studying these 'split-brain' patients has revealed a lot about the hemispheres. For example, patients cannot name an object, say an apple, shown on their left-hand side even though they recognise it. This is because information about the apple is sent to the right side of their   brain, but cannot cross to the left side, which usually deals with language.