
Autism is a developmental disorder that can cause problems with social interaction, language skills and physical behaviour. People with autism may also be more sensitive to everyday sensory information.
To people with the condition the world can appear chaotic with no clear boundaries, order or meaning.
The disorder varies from mild to so severe that a person may be almost unable to communicate and need round-the-clock care.
Research has revealed that people with autism have brains that function in a number of different ways to those without the condition.
One recent study suggested that people with autism tend to have far more activity in the part of the brain called the amygdala when looking at other people's faces. The over-stimulation of this part of the brain that deals with new information may explain why people with autism often have difficulty maintaining eye-contact.
Specific nerve cells in the brain, called neurones, also act differently in people with autism. Mirror neurones help us mimic useful behaviour so we can learn from others.
Brain imaging studies suggest that the mirror neurones in people with autism respond in a different way to those without the disorder.
This could partly explain what many behavioural studies have already shown - that children with autism can find it difficult to copy or learn simple behaviours from others. Scientists have suggested with social interaction could have a knock-on effect on language learning.