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Features May 2004: Volume 1, Number 2
   

Autism, The Epidemic
(continued)

 
     

***

Over the bluff and down La Jolla Shores Drive, Eric Courchesne (Cor-Shayn), Ph.D., ’75, and his colleagues are having success with a very different approach.

Courchesne and his colleagues do their work a few blocks from the beach in a teal and white converted office, with an Excel Fitness Center and a State Farm Insurance office as neighbors. Though the building is simple and nondescript, it is home to some of the most advanced brain scanning equipment at UCSD. Courchesne and his colleagues study why children become autistic in the first place, what happens to the brain during those first critical years.

For a long time after the discovery of autism, researchers could find nothing obviously wrong in the brain that might cause the disorder. Unlike Alzheimer’s disease or spongiform encephalopathy, there were no identifiable neural tangles or dead spots in the brain.

In the mid 1980s, Courchesne’s lab used magnetic resonance imaging (MRI) to show that the part of the brain called the cerebellum is underdeveloped in autistic people. The cerebellum, a finely wrinkled structure that sits behind and below the rest of the brain, has long been thought to be involved in learned motor skills and coordination. But Courchesne was one of the first researchers to show that the cerebellum plays a part in attention, arousal, and the integration of sensory information—precisely the things that seem to be lacking in autistic children.

In more recent research, he noticed that autistic children tend to have larger heads—and brains—than other children. Children who would later become autistic had heads that were on average a little smaller than normal at birth, but went through very rapid brain growth during their first year. By the time they were diagnosed with autism, these children had average head sizes in the 85th percentile, which meant that seven out of eight children had smaller heads than they did.

The study, which he published in 2003 with UCSD researchers Ruth Carper, ’01, and Natacha Akshoomoff, ’92, was significant. Unlike other autistic brain findings, these changes actually preceded the diagnosis of autism. There is a good chance that the overgrowth of the brain during the first year is a cause, rather than an effect of the autism.

Courchesne’s working model is that brain growth is supposed to occur slowly, shaped by the feedback of everyday experience. “Without the guidance of experience and learning, the brain may be creating abnormal connections that make it very hard for autistic children to make sense of the world they live in,” he says.

The autistic brain may be like a garden that turns into a jungle, because the plants and weeds grow too quickly for the gardener to keep up.

This idea might also offer an explanation as to why autistic children withdraw from the world, Courchesne and others say. While most of us are easily able to block out random noises, sounds and sights around us, concentrating only on what is important, autistic children don’t have this ability. Their massively overwired brains are like giant seine nets, capturing every stimulus in their environment and becoming unbearably overexcited. Withdrawing, rhythmic rocking and focusing on inanimate objects may be just some of the ways that people with autism calm themselves.

Rapid increases in head size might also offer an easy diagnostic test—one that could help parents catch autism early, when it is most amenable to treatment. “If pediatricians did head circumference measurements at each visit through the first year they might catch an abnormally rapid brain growth and refer the child for further testing,” Courchesne says.

***

Other researchers at UCSD are studying autism partly for what it can tell us about the disorder, and partly for what it might tell us about how the brain normally works. V.S. Ramachandran, the director of the Center for Brain and Cognition, teamed up with Jaime Pineda, ’87, director of UCSD’s Cognitive Neuroscience Laboratory, and Eric Altschuler, Ph.D. ’99, to study what are called mirror neurons. These neurons, located in the premotor cortex, fire both when we do an action and when we see others do the same action. Also called the “monkey see, monkey do” neurons, they are thought to be involved not only in actions, but also in higher functions like being able to put yourself in others’ shoes, to imitate and learn from others’ actions, and intuit others’ intentions. These neurons are also thought to be involved in language and communication.

These abilities are precisely what autistics are deficient in, so Ramachandran, Altschuler and Pineda compared the activity of the mirror neurons in normal and autistic subjects. They found that although the mirror neurons were active when the autistic subjects performed an activity, the neurons were silent when the same subjects observed others performing the same activity.

Ramachandran believes this may be the key difference in autistic brains, underlying many of the common aspects of autism. He points out, however, that knowing the neural deficit still doesn’t explain why the mirror neurons fail to do their job. “It could be genetics, it could be inflammation, it could be predisposition to viral infection,” he says. He believes that once we understand what’s going on in the brain we can, perhaps, treat the cause, and help the mirror neurons to function normally again.

***

The rapid rise in autism diagnoses has prompted desperate parents, as well as real and self-appointed “experts,” to identify various possible reasons for the epidemic, even though it’s not clear that the number of autistic children has really increased at all.

“ Part of the rise in diagnosis is the result of increased awareness, better diagnostic tools, knowing what to look for in younger children, and better services for autistic children,” Schreibman says. “I’ve had doctors tell me that if a diagnosis of autism will get the child more help, and they can squeeze out that diagnosis, they will.

“ To some extent the rise in autism cases may be real, but I don’t believe that the rate of autism has really increased by a factor of 60,” she says.

That hasn’t stopped people from blaming the mercury in vaccines, environmental toxins, food additives, infections and various other causes for their children’s condition. Seeking to bring reason and information to the debate, Schreibman is publishing a book in November called The Science and Fiction of Autism (see sidebar, page 20). She understands that parents are angry, scared and desperate, but she would like them to be able to think critically about the controversies, to understand a little more about how science works and how evidence is gathered.

This mission is something Schreibman works on every day. On the ground floor of McGill Hall, an adorable 2-year-old named Tyler drapes himself over a chair, happily pressing his cheek against the vinyl seat. In one of the toy-filled rooms off the main hall, Schreibman and her colleagues will work with Tyler, encouraging him to express himself, to interact, to make contact. Just as important, they will be working with Tyler’s mother, teaching her about her son’s condition, modeling teaching techniques, lifting her hopes when they can and tempering her expectations where they must.

“ You can’t sit out waiting for a miracle pill that is going to cure everything,” Schreibman says. “All I can do is offer years of hard work, but it’s what we have, and it can make a huge difference.”

Christopher Vaughan has written numerous books and articles on medical topics. He lives in the Bay Area.

RELATED LINKS

UCSD Psychology
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UCSD Autism Research Study
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National Alliance for Autism Research
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Children's Hospital Autism Intervention
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TeachTown
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"You only get one shot in doing that early intervention and helping these children...so you want to make sure you are using the right treatment."