Brains of people with autism remember letters of the alphabet in a region that normally processes shapes, one of several findings with functional magnetic resonance that support the hypothesis that autism involves impairment in cooperation among different brain regions, according to an article published online November 29th by the journal Neuroimage.

In autism, according to the hypothesis tested by the researchers, these distinct brain areas tend to work independently of each other. The theory accounts for observations that while many people with autism excel at tasks involving details, they have difficulty with more complex information.

"This finding provides more evidence to support a promising theory of autism," said Duane Alexander, MD, of the National Institutes of Health. "If confirmed, this theory suggests that therapies emphasizing problem solving skills and other tasks that activate multiple brain areas at the same time might benefit people with autism."

People with autism typically have difficulty communicating and interacting socially with others. The old saying "unable to see the forest for the trees" applies to people with autism, describing how many of them excel at matters of detail, yet struggle to comprehend the larger picture. For example, some children with autism may become champions at spelling bees, but have difficulty understanding the meaning of a sentence or a story.

"The language pattern in autism is a microcosm for the disorder," Just said. "People with autism are good at a lower level of analysis but have a deficit at the higher level."

In the current study, the researchers used functional magnetic resonance imaging (fMRI) to measure the brain activity of 14 individuals with high functioning autism while they performed a simple memory task involving letters of the alphabet.

Specifically, the study volunteers were shown a sequence of letters. After each letter, they were asked to name the letter that preceded it. In some cases, they were asked to name the letter that appeared two letters previously. The autism volunteers' brain activation patterns were compared with those of a control group who did not have autism but were of a similar age and intelligence.

Both groups successfully completed the task. However, the scans revealed different brain activation patterns. Compared with controls, volunteers with autism showed more activation in the right hemisphere and less activation in the left hemisphere. The left hemisphere takes the lead in processing letters, words and sentences, whereas the right hemisphere plays a larger role in processing shapes and visual information.

Just said that the brain could interpret letters either spatially, as geometric shapes, or linguistically by the names of the letters. The imaging data indicated that the volunteers with autism remembered letters as shapes, while the control group remembered them by their names.

The brain activation patterns of the two groups also differed in other ways. While performing the task, the group with autism showed less activation in the anterior parts of the brain and more activation in the posterior regions, a finding that supports the premise that autism involves impairment of higher-level thinking and reasoning while maintaining at least average function in perception of details.

In addition, different brain regions in people with autism were less likely to work in synchrony while recalling the letters. Such synchronization between brain areas takes place during many kinds of higher-level thinking and analysis that prove difficult for many people with autism.

Many behavioral therapies to treat autism stress rote learning, according to the authors explained. Such strategies are helpful, particularly early in a child's development. However, if the theory of underconnectivity proves valid, therapies that stimulate brain areas to work in synchrony might also offer some benefit. Such therapies might stress problem solving skills and creative thinking, and attempt to foster flexibility in thinking.