Brains of People with Autism Recall Letters of the Alphabet In Brain Areas Dealing With Shapes|
Finding Supports Theory That Autism Results From Failure of Brain Areas To Work Together
In contrast to people who do not have autism, people with autism
remember letters of the alphabet in a part of the brain that ordinarily
processes shapes, according to a study from a collaborative program
of the National Institute of Child Health and Human Development
of the National Institutes of Health.
The study was conducted by researchers in the NICHD Collaborative
Program of Excellence in Autism (CPEA) at the University of Pittsburgh
and Carnegie Mellon University. It supports a theory by CPEA scientists
that autism results from a failure of the various parts of the brain
to work together. In autism, the theory holds, 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.
The study and the theory are the work of Marcel Just, Ph.D., Professor
of Psychology at Carnegie Mellon University in Pittsburgh, Pennsylvania
and Nancy Minshew, M.D., Professor of Psychiatry and Neurology at
the University of Pittsburgh School of Medicine and their colleagues.
The study is scheduled for on-line publication November 29 in the
journal Neuroimage, at http://www.sciencedirect.com.
"This finding provides more evidence to support a promising
theory of autism," said Duane Alexander, M.D., Director of
the NICHD. "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
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,"
Dr. 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 a brain imaging technique
known as 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 to a control group of people who
did not have autism, but were of a similar age and I.Q. level.
Both groups successfully completed the task. However, the fMRI
scans revealed different brain activation patterns between the two
groups. Compared to the control group, the volunteers with autism
showed more activation in the right hemisphere, or half, of the
brain, 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
Dr. 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
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, or front, parts of the brain, and
more activation in the posterior, or rear parts of the brain. Dr.
Just explained that the brain's anterior portions carry out higher-level
thinking and reasoning while the posterior portion is more involved
with perceiving details.
Compared to the control group, the different brain areas of the
people with autism were less likely to work in synchrony (at the
same time) 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.
These current findings provide evidence in support of the theory
developed by these researchers. Called the theory of underconnectivity
in autism, it maintains that autism results from a failure of the
brain's neurological wiring the fibers of nervous system tissue
that interconnect the individual parts of the brain. Deprived of
effective connections, the different brain areas must work independently,
sometimes performing at a higher level individually than they do
in people who do not have autism. This may allow some people with
autism to excel at spelling and other detail-oriented tasks but
make it difficult for them to comprehend more complex material.
The researchers published their theory in the July issue of Brain,
in conjunction with the results of another fMRI study of volunteers
with autism. In that study, volunteers were asked a question about
a simple sentence that they had just read. When the people with
autism performed the task, their brains showed less synchronization
than did the brains of the control group. Moreover, the brains of
the group with autism had less activation in an anterior part of
the brain that integrates the words of a sentence, and more activation
in a posterior brain area that comprehends individual words.
Many behavioral therapies to treat autism stress rote learning,
Dr. Minshew 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
Dr. Just noted that more evidence to support the theory might come
from the group's on-going studies of other cognitive abilities.
The researchers are attempting to determine if underconnectivity
is a general feature of the brain in autism, and are using brain
imaging studies to examine the brain's white matter in people with
autism. White matter is the part of the brain that consists of the
larger neurological connections spanning different parts of the
The NICHD is part of the National Institutes of Health (NIH),
the biomedical research arm of the federal government. NIH is an
agency of the U.S. Department of Health and Human Services. The
NICHD sponsors research on development, before and after birth;
maternal, child, and family health; reproductive biology and population
issues; and medical rehabilitation. NICHD publications, as well
as information about the Institute, are available from the NICHD
Web site, http://www.nichd.nih.gov,
or from the NICHD Information Resource Center, 1-800-370-2943; e-mail