Contra Costa Times, May 9, 2004
SACRAMENTO, California, USA: Nearly 400 of the world’s top autism researchers gathered in Sacramento on May 7 for the third annual International Meeting for Autism Research (IMFAR).
The gathering, sponsored by the National Institutes for Health, the M.I.N.D.
Institute at University of California – Davis, Cure Autism Now and the
National Alliance for Autism Research, concluded on May 9.
By expanding their knowledge of how infant brains develop, scientists seek
to solve one of the biggest puzzles surrounding the autism
explosion: Why do many parents report that their children develop normally,
then suddenly regress at about 18 months or two years?
Dr Steve Dager, a researcher at the University of Washington, said his team
found that at the age of three or four, autistic children have larger
cerebral brain volumes than their counterparts. The cerebrum consists of
dense, convoluted masses of tissue. The outer layer is the cerebral cortex
or gray matter. In adults, the cortex contains most of the nerve cells in
the nervous system.
“What we’re finding is that by the age of six, this kind of interesting
over-growth of the brain or larger brain is no longer apparent,” Dr Dager
said.
Kimberley McAllister, of the Center for Neuroscience at UC Davis, has
focused on uncovering growth patterns in the cerebral cortex during the
first two years of life. She has zeroed in on synapses, or the point at
which an electrical impulse passes from one nerve cell to another. “The
development of these synapses is incredibly critical for proper functioning
of the brain,” she said, noting that it is where information processing
takes place. Her lab is looking at the core components of synapses,
including the hundreds of proteins involved.
Because the formation of synapses occur at about the time autistic symptoms
emerge in many children, “we believe that something about this process of
cellular growth is part of what is causing autism,”
she said.
Several other researchers recently published papers suggesting that
abnormalities in a protein known as neuroligin, which plays a role in
forming synapses, may be a factor leading to autism, McAllister said.
While some scientists focus on brain development, others search for clues in
the unusual behaviour of autistic children, who often engage in repetitive
activities such as hand-flapping, rocking, lining up Lego bricks, adhering
to rituals and becoming upset with change.
It is one of the most understudied fields of autism, said one leading expert
on repetitive behaviour. “Somehow, (autistic) individuals are using these
behaviors to order their environment,” said Mark Lewis, a behavioural
scientist at the McKnight Brain Institute at the University of Florida. Yet
little is known about why they are drawn to such activities.
Experiments with mice shed some light, however. Using drugs, scientists
interrupted the circuitry in mice’s basal ganglia, an area of the brain that
helps the cortex to prioritise information. That affected the animals’
repeated jumping, backflips and other repetitive behaviour.
Research on the brain and behaviour may reveal what leads to autism, but it
leaves unanswered the question of what triggers it.
Most researchers believe genetics play a role. But others wonder whether an
environmental factor, such as exposure to a toxic material or a reaction to
a vaccine, may push genetically vulnerable children over the edge into
autism.
Many children make progress with early intervention, but there is no cure.
Scientists have scrambled for answers because of a rapid rise in the number
of autistic children throughout the United States, England, Scotland and
other countries. The disorder takes an emotional toll on families and
burdens governments with costly services.
“Each one of these meetings gives us new opportunities to learn about autism and to build a more complete foundation from which to work,”
said the conference chairwoman, Sally Rogers, in her welcoming letter. “We
will come to understand this disorder based on our collective knowledge, not
any one person’s knowledge.”