Six-year-old Stacey Schablein of Bowie has undergone 18 operations to correct the effects of hydrocephalus induced by a stroke she suffered two days after she was born.

She was not able to sit up until she was a year old and did not walk until she was 2. Her ability to use her hands in drawing, writing and playing with building blocks has been affected by her condition. But her parents, Jerry and Marie Schablein, say they are relieved that Stacey shows no signs of mental retardation.

Stacey's medical care has cost about $135,000 so far, and about $50,000 is not covered by insurance. The Schableins said their medical coverage was interrupted when Jerry Schablein, a paint salesman in Washington, changed jobs.

The Schableins are looking to the Brain Research Center, established last summer at Children's Hospital National Medical Center, as the newest hope for the discovery of better ways to treat disorders like Stacey's and develop methods that will help her.

"Perhaps we won't have to wait another five years for somebody to develop slowly and piecemeal the technology that's needed to make new discoveries," said Jerry Schablein, the first president of the Brain Research Association, a group of parents pledged to help raise money for the research center.

"I don't want to see other children suffer the way Stacey did. And I don't want other parents to have to go through the anguish of not knowing whether your child is going to live or die, whether there's permanent brain damage and the fear of what your child's future is going to be like," said Marie Schablein, explaining why she and her husband took an active role in forming the association.

The center will zero in on the functions of children's brains, both normal and abnormal. Experts say that even such functions as walking and sleeping may be different in children than in adults, and that children also will react differently to disorders such as strokes and tumors.

Researchers at the center are studying the whole spectrum of children's neurological disorders and eventually hope to establish a centralized computer network through which scientists can channel information about the latest breakthroughs to doctors throughout the country.

"Our goal is to open the blood-brain barrier which normally protects an individual from poisonous environmental influences," said Dr. Kathryn Hammock, clinical director of the Department of Neurosurgery at Children's Hospital and associate director of the Brain Research Association. "Mother Nature is wonderful, but when you want to treat the problems that lie beyond the blood-brain barrier, like infections and tumors, it becomes our foe."

Physicians believe that the blood-brain barrier is a closely aligned layer of cells that effectively blocks most substances from being absorbed into the brain's tissues.

Hammock expects that by September, "We will have a prototype experiment for evaluating the effects of drugs used and abused and their effects on the neurological system," she said.

Researchers at the center study the brains of rats and other laboratory animals for clues about how the brain develops, both normally and abnormally, to determine the effects of various chemicals on the brain, and to observe its metabolism and other functions.

The studies include research on phenobarbital, a drug commonly used to control seizures in children. It is unclear how much of the drug is necessary to control seizures, and whether anything beyond that amount will affect other neurological functions, according to Dr. John Miller, research fellow for the center. The importance of this research, said Miller, is learning how phenobarbitol affects the brain and what changes might take place in brain blood flow and metabolism.

The center's primary tool is a computer-assisted brain scanning device called Quantitative Autoradiography (QAR), which enables researchers automatically to scan the dissected brains of laboratory animals that have been treated with radioactive isotopes such as carbon 14. Various brain functions like metabolism, blood flow and absorption of drugs appear in three-dimensional color on a television-like screen.

However, Dr. Lewis Sokoloff, chief of the laboratory of cerebral metabolism at the National Institute of Mental Health and a developer of the QAR method, was cautious in his evaluation of the QAR scanner as a tool to solve the mysteries of children's neurological disorders. "There're all kinds of technology but I'm not sure the QAR will make all that much difference by itself in solving problems," he said. "The technique is terrific . . . but it's nothing except when it's part of a method--like measuring things in the blood."

One of every four children who enter a pediatric hospital and one of every two who die there was afflicted by a neurologically related disorder, according to statistics compiled by hospitals around the country. One infant in 300 is born with hydrocephalus, commonly called "water on the brain," one of the most common causes of mental retardation.

In an effort to change these grim statistics, the parents active in the Brain Research Association are exploring innovative ways to raise money for the Brain Research Center. The association hopes to raise at least $150,000 each year for the center. It also hopes to improve public awareness and to enlist community support for its activities. So far, the association has raised nearly $400,000, in addition to the space, personnel and salaries donated by Children's Hospital and the National Institutes of Health (NIH). The center has a staff of five: two clinical researchers, one computer specialist and two research fellows.

The bulk of the initial funding has come from conventional sources: a $200,000 grant from the Fleischmann Foundation; $75,000 from the Gitelson Fund, founded by a family with a son who died of a brain tumor, and $50,000 contributed in the names of children, both living and dead. Several members of the association had children who died of brain disorders.

Other money has come from a junior high school "danceathon," a race track dinner, an antique-doll raffle, direct appeals to friends and relatives of the parents and children, and even a door-to-door canvass, made by a youth recovering from a brain tumor, that netted $300. A National Theater benefit performance of "The Pirates of Penzance" raised $30,000.

The BRA has also established a community outreach program and a psychological support center for parents and families of young patients.

"Sister" research centers have opened at the University of Rochester in New York and the State University of New York Downstate Medical Center in Brooklyn. Both centers will coordinate their research efforts with those at Children's Hospital.

Dr. Thomas H. Milhorat, director of the BRA and former chief of neurosurgery at Children's Hospital, is now chairman of neurosurgery and director of the research center in Brooklyn. He is the son of Dr. A.D.E. Thomas Milhorat, one of the Muscular Dystrophy Association's founders.

Thomas Milhorat said his father's experience, coupled with the interest of the parents of Children's Hospital patients in getting an MDA-style campaign started for their children and others with similar disorders, inspired the establishment of the research center and its supporting association.

"I remember sitting in on MDA's first telethon 3l years ago which was only carried by one TV station in New York," Milhorat recalled. "It's now become the nation's most successful charity."

The BRA hopes to be equally successful in attracting celebrities and funds to its cause. So far, its efforts have met with mixed results. The association also plans to solicit support from local businesses, fraternal organizations, parents and physicians to escalate the pace of its research efforts, association officials said.