A guide to dementia science

We fund cutting-edge research into the cause, cure, care and prevention of dementia. If you are new to dementia science, this guide will answer a few of the questions you may have and explains some of the terms that you will come across.

How the brain works

Inside the brain

The brain is the most complex organ in the human body and is separated into regions responsible for certain functions. It contains many specialised cells. Over the years we have begun to understand how each type of brain cell works. However, it is still not clear how these cells are linked together to perform complicated actions and why problems in cells cause changes in behaviour. The cerebral cortex makes up the bulk of the brain and is the location of complex thoughts and functions. Each half, or hemisphere, of cortex is made up of four lobes.

Neurons

There are two main types of brain cells: the nerve cells or neurons, which relay signals like thoughts and feelings, and the supporting cells. There are 100 billion neurons in the brain. They are elongated with many tentacle-like projections that make contact with other cells around them. Messages are passed within cells by tiny electrical impulses and between cells by chemical signals. Like any other cells in the body, neurons require oxygen and nutrients to stay alive. They also rely on close contact with neighbouring cells. Without these a neuron will die.

Supporting cells

There is roughly one supporting cell for every neuron in the brain. These cells surround and provide support to neurons, supply nutrients and oxygen, regulate communication between neurons and act as the brain's immune system. Two of note are: astrocytes which regulate the environment of the brain and are crucial in forming the 'blood-brain barrier' that protects the brain, and oligodendrocytes, which surround, protect and insulate neurons and are essential for effective cell communication.

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