Scientists discover why people with autism may literally see the world differently
Autism may be driven by unusually wired visual circuits in the brain which make babies literally see the world differently, scientists believe.
Researchers at the University of North Carolina (UNC) scanned the brains of six-month-olds who were at high risk of developing autism because their siblings had already been diagnosed with the condition.
They found that those babies who went on to develop autism by the age of 24 months had weaker connections between brain networks involved in object recognition and steering the attention to things happening in the wider environment.
“We think aberrant visual circuitry is a fundamental cog in the cascade of events leading to later autism,” said Dr Joe Piven, of the Carolina Institute of Developmental Disabilities (CIDD) at UNC.
“We think this circuitry alters how infants experience the world, and how they experience the world alters how their brains subsequently develop.
“It’s this secondary altered brain development that may result in what we call autism that typically emerges in the latter part of the first and second years of life.”
The early years of life are crucial for brain development and babies lock eyes with their parents to learn how to communicate before that ability gets generalised to other people.
The new research suggests that in babies who go on to develop autism, something goes awry in the brain’s visual system that impacts this usual visual interplay.
Previous studies have shown that communication often breaks down between children at risk of autism and their parents because youngsters often seek attention without holding eye-contact.
Coaching parents could reduce chances of diagnosis
Coaching parents to spot when babies are trying to communicate reduced the number of children being diagnosed with autism at the age of three, from 20.5 per cent per cent to 6.7 per cent.
In the new research, scientists scanned the brains of 384 babies with brothers and sisters who had already been diagnosed with autism. Studies have shown that younger siblings have a 14 times higher risk of developing autism if an older sibling has the condition.
In youngsters that went on to develop autism, brain differences were found in two parts of the visual processing system – the occipital gyrus, which is important for object recognition, and the splenium, which is important for communicating between different hemispheric parts of the visual system and orienting attention.
They found the brain differences were present well before the youngsters began showing symptoms of autism as toddlers.
Researchers said behavioural interventions aimed at the visual and related brain systems in the first year of life in infants could prevent children developing more severe autism traits.
The research was published in the American Journal of Psychiatry.
