Parts of the brains of people with autism are more active in areas that deal with visual detection and identification and less in areas for decision making, planning and execution, and cognitive control, researchers from the University of Montreal revealed in the journal Human Brain Mapping. Dr. Laurent Mottron, at CETEDUM (University of Montreal's Centre for Excellence in Pervasive Development Disorders) believes their findings explain why most people with autism tend to be extremely good at visual tasks.
Dr. Mottron and team set out to find out why individuals with autism are good at processing visual data. They gathered 15-years' worth of information covering ways their brain functions when interpreting written words, faces and objects. They examined 26 different brain imaging studies, involving 727 individuals, 357 with autism and 370 without.
First author Fabienne Samson, said:
"Through this meta-analysis, we were able to observe that autistics exhibit more activity in the temporal and occipital regions and less activity in frontal cortex than non-autistics. The identified temporal and occipital regions are typically involved in perceiving and recognizing patterns and objects. The reported frontal areas subserve higher cognitive functions such as decision making, cognitive control, planning and execution.
This stronger engagement of the visual processing brain areas in autism is consistent with the well documented enhanced visuo-spatial abilities in this population."
The researchers say their findings indicate that the brain of a person with autism is reorganized to favor perception processes - the processes by which the brain records data. This allows a person with autism to successfully perform - in their own way - higher-level cognitive tasks which would usually involve more activity in the frontal areas of the brains of those without autism. Cognitive tasks require reasoning, as might be the case when one is asked to determine whether a statement is true or false, or categorize a series of objects into different groups.
Put simply - it appears that the autistic brain is organized differently. The back of the brain is more highly developed - the part that deals with processing what we see (visual information). However, this leaves less brain capacity in parts of the brain that deal with planning and decision-making.
Dr. Mottron said:
"We synthesized the results of neuroimaging studies using visual stimuli from across the world. The results are strong enough to remain true despite the variability between the research designs, samples and tasks, making the perceptual account of autistic cognition currently the most validated model. The stronger engagement of the visual system, whatever the task, represents the first physiological confirmation that enhanced perceptual processing is a core feature of neural organization in this population.
We now have a very strong statement about autism functioning which may be ground for cognitive accounts of autistic perception, learning, memory and reasoning."
How does the autistic brain adapt? According to their findings, the researchers say that the autistic brain simply reallocates areas to visual perception. This may help scientists decide how to proceed with future research, perhaps focusing more on developmental brain plasticity and visual expertise in individuals with autism.
Dr. Mottron believes their findings may redirect experts when they devise new and more effective ways of helping people live with autism. Literacy should perhaps be taught in a much more natural way than what is currently being used with autistic people.
Rather than a form of disorganization, Mottron added, autism involves a reorganization of the brain.
Perhaps the wrong approach is to simply see autism as a condition with a set of behavioral problems. In order to understand the needs of an individual with autism, we should determine what his/her strengths and difficulties are.
"Enhanced visual functioning in autism: An ALE meta-analysis"
Fabienne Samson, Laurent Mottron, Isabelle Soulières, Thomas A. Zeffiro
Human Brain Mapping DOI: 10.1002/hbm.21307
Written by Christian Nordqvist