CHAMPAIGN – Bouncing around the auto showroom, tussling with his big brother over their toy cars, Mark Davis is the epitome of a busy 3-year-old.

His bright, hazel eyes, ready smile and willing hug betray no sign of a disability. He is, as a family friend comments, "100 percent boy."

Things weren't so easy a year ago.

Mark has autism, a brain development disorder characterized by impaired social interaction and communication, among other traits.

Though highly intelligent, with a strong vocabulary, he couldn't access words when he needed them. He didn't know how to interact with other children or even adults. He'd play with his Matchbox cars from 7 a.m. until 7 p.m. every day, refusing other toys.

Worst of all, he was so sensitive to sound he'd fall easily into sensory overload – crying, screaming, banging his head or running in circles when he'd had too much. His parents kept close to their Savoy townhouse because even a half day out to run errands and go to the park was too exhausting.

"We couldn't go anywhere," said mom Bethany Davis, who with husband Tom has two other sons. "It took so much energy we didn't do it."

An avid reader, she recognized Mark's symptoms early on as possible autism – poor eye contact, a lack of interest in the world around him, speech delays and missed developmental milestones. He didn't reach for toys, clap, wave or point to things. He sat up late, smiled late and "had a sort of general 'blah' about him," she said.

So she wasn't surprised by the diagnosis. But she was taken aback at the extent of his delays: a full year behind in language development.

Through the state's Early Intervention program, the family wound up at Developmental Services Center in Champaign last September. There, Mark received weekly language therapy and developmental play therapy, and his parents began to see progress. His developmental therapist slowly introduced puzzles, blocks and other toys. She taught Mark how to include others in his play. She explained her strategies to his parents so they could work with him, too.

His language therapist, working with an outside occupational therapist, discovered Mark could pick up language skills more easily if he was getting other sensory input at the same time. She'd have him jump on a trampoline, climb trees or ride his tricycle while she talked with him.

He also attended a preschool play group, where he learned to interact with other children, follow instructions, clean up toys and make transitions from one activity to another – all major hurdles before.

Having his therapists in one place, where they could consult with each other, was invaluable, Bethany Davis said. "He made great gains. He wouldn't have made this kind of progress with just me."

Mark is now in preschool at Champaign's Early Childhood. He's still working on his social and language skills: When he dropped a car the other day, he said, "Tell that car not to go away from me."

"He has a lot of words that kids his age might not have; he just doesn't know how to use them properly," she said.

But overall he's "doing great. We can go out in public."

The Davises are the spokesfamily for this year's Tree of Hope campaign, DSC's main fundraiser. They can't say enough about the help the whole family received at DSC. Timothy, now 7, went to a sibling support group for several months, and Jeffrey, 1, is now enrolled in a play group as a "typical child."

"We're still benefiting from them," Bethany Davis said. "We've been thrilled."

And the family hasn't had to pay for any of the services.

"I hope people just get how important this is for families like ours. We never knew we were going to be in the position of needing their services. We could never have paid for this out of our own pocket."

Developmental Services Center launched its 15th annual Tree of Hope campaign Thursday, its largest fundraiser of the year. The details:

Goal: $75,000 (same as 2007). Last year's drive collected $85,000. Sponsors underwrite all fundraising costs.

How it works: Every $50 in contributions made through Jan. 30 will light one bulb on DSC Tree of Hope at corner of Prospect Avenue and Marketview Drive, Champaign. Donations so far total $10,000.

About DSC: Provides services for more than 1,300 children and adults with developmental disabilities each year in Champiagn, Ford, Piatt and Iroquois counties. Mission is to help those with epilepsy, cerebral palsy, autism, Down syndrome, mental retardation and other disabilities live, work and participate in their communities.

How to donate: Call 356-9176.

Major sponsors: Herff Jones (Cap & Gown Division), Kraft Foods, Sullivan-Parkhill Automotive Inc., National City, Patterson Co., WDWS/WHMS, and WICD-TV.