At Carnegie Mellon University, it's standing room only for this autism conference.

Organizers expected just 120, but 400 to 500 people showed up, including professors, students and parents.

"The more we know, the more we don't know. And I'm not here to hear a cure, or fix anything. I want to do what's best for the child..." says Natalie Bennett of Squirrel Hill, the mother of an 8-year-old with autism, and a 10-year-old with Asperger's syndrome.

"I work in the field of autism," says Kelly Morton of Pittsburgh, "and I just wanted to hear Temple Grandin speak, and get some of the new research."

Temple Grandin, spoke early in the day. She is an animal researcher and a well-known person with autism.

Dr. Kathrin Hippler, a clinical psychologist from Vienna, reviewed what has happened with Dr. Hans Asperger's actual patients from the 1950s through the 1970s...boys who were bright, had narrow interests and were socially awkward.

"You can absolutely feel he was fascinated by these children," she says

He was the first to describe in 1944 the syndrome known as Asperger's, a high-functioning form of autism. One-sided conversations, a lack of eye contact and empathy, narrow interests, a monotonous voice, and poor coordination -- these are some of the symptoms. This was just one topic discussed at this symposium about the brain and autism.

"If you talk to people in different countries, you'll find they all have very different concepts on how to diagnose Asperger's syndrome and autism," Dr. Hippler points out.

"We don't have a medical test, an x-ray, or a blood test, to tell us whether the individual falls into one category or another," explains Dr. Dena Hofkosh. "So criteria for what behaviors make the diagnosis, it's an evolving field."

Dr. Hofkosh, a developmental pediatrician at Children's Hospital, hopes to attend the conference.

"I think it's fascinating to know, to learn what we know, what people are finding out about how the brains of individuals with autism and Asperger's syndrome, how they process information differently," she says enthusiastically.

The symposium is open to the public. It runs through October 18th in Baker Hall at Carnegie Mellon University.