A discovery has offered fresh hope of developing a method to diagnose autism in toddlers.
Researchers from the Weizmann Institute of Science in Rehovot, Israel, made the find while measuring the neural activity of sleeping toddlers.
They found that language areas in the right and left sides of the brain are less synchronised in autistic children and that the weaker the synchronisation, the more severe the communication difficulties exhibited by the child.
Lead scientist Dr Ilan Dinstein said that in a normal brain, neurons in separate areas belonging to a system with a particular function, such as language, always stay in sync.
But findings from his team, published in the journal Neuron, show that this "sync" was significantly weaker in brain areas that are responsible for language and communication abilities in children with autism.
He said: "Many things need to be set up right during brain development to enable normal sync between different brain areas. The wiring between the brain areas needs to be right and the neurons within each brain area need to send and receive their messages properly."