Autism: Human Social Behavior

A vexing burden for millions of children, adults, and families, an enigma and a challenge to researchers: this is autism as Catherine Lord, Ph.D., described it in Columbia University’s inaugural Brain Insight Lecture, sponsored by the Stavros Niarchos Foundation and hosted by the Zuckerman Mind Brain Behavior Institute.

Lord, director of the Center for Autism and the Developing Brain at New York-Presbyterian Hospital Center, reported progress in understanding this increasingly important disorder, while emphasizing the need for neuroscience to illuminate its mysteries.

One goal of her talk, she said at the outset, was “to inspire the neuroscientists who are here to think about what’s going on in children and adults we see with autism.”

Reported prevalence has increased dramatically in recent years, she observed. “When we started studying autism, we thought it affected four in 20,000 people; now we know it’s one percent or even two percent of the population.”

While improved identification has surely played a role, it alone is unlikely to explain this increase, she said in response to an audience question. “It’s hard to believe that autism was always there and we didn’t see it.”

In fact, much about autism remains mysterious. While brain dysfunction clearly underlies the disorder, no replicable, consistent neurobiological differences between autistic and other individuals have been identified, and it is defined solely by behavior.

This behavior has two distinct features. Abnormal social interaction: people with autism look at, communicate, and respond to other people differently. They also may display an odd assortment of limited and repetitive behaviors—such as stereotyped movements and intense preoccupation with subjects such as aquariums or train timetables.

“Why these things—social deficits and restricted behaviors—are connected, what it is about the brain that relates them…this is a question for neuroscience,” Lord said.

Autism is the most clearly genetic of childhood psychiatric disorders, and “many of us were taught that genetics would solve it,” she said. But while hundreds of associated genes have been identified, no one stands out, and many genetic patterns are common to other psychiatric and developmental disorders as well. “We need some kind of final common pathway,” she said.

Yet understanding of autism has advanced substantially. We recognize “a huge range of [variability] as children with autism grow up, including some who do quite well,” Lord said. In one study that followed several hundred children into early adolescence, 80% remained at the level of severity when first diagnosed and 10% got worse, but nearly 10% improved markedly. She has helped develop more precise, reliable methods of measuring autistic behavior and predicting its course.

“We’re hopeful that this will lead to insights about how to help people with autism and their families. We already know much more about communication and the complexities of human social behavior than we did before,” she said.

“But we really need neuroscience to understand what’s awry in the brain, and what can be done about it.”

When an audience member decried the “huge disconnect… between clinicians who treat children with autism and basic research in neuroscience,” Lord agreed that such “cross-pollination” has been lacking.

But the obstacles that researchers face are formidable, she said. Animal models of relevant social behavior remain “fairly crude.” A genetically modified mouse that spends less time than normal seeking out other mice, for example, is “very far from autism, and from human communication,” she said.

“Another part of the problem is that there aren’t great methods of measuring brain function while people are interacting with one another.” An fMRI study might require subjects to lie in a noisy metal tube while looking at faces or videos of social encounters. “We don’t know if a child with autism reacts as the rest of us would under these conditions,” she said. “We need methods to measure brain function while people are moving, having interactions.”

That said, basic research has yielded some potentially useful insights into the autistic brain, she said. The fusiform gyrus, a part of the visual system, is normally activated when we look at faces. But repeated fMRI studies have shown that autistic children and adults activate different brain circuits instead. “There’s a lot of controversy over whether this is because of how autistic kids process social information, or because they’ve looked at faces a lot less.”

One recent MIT study indicated that normally intelligent children with autism can recognize faces as well as others, but have difficulty remembering them, suggesting abnormalities in highly specific functional pathways.

“Clinically, I think I can use that,” Lord said.

–Carl Sherman

Carl Sherman is a science writer in New York City.

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