Roland Strauss is so positively charmed by fruit flies that he has staked his entire career on analyzing them with lasers to see why some limp and strapping them into a virtual reality chamber to understand how they judge distances based on the scenery in front of them.

He is convinced that if he can unravel how flies are able to walk in a straight line, or navigate a twig, or balance on top of peach fuzz, his research will contribute to a much larger prize: deciphering the mysteries of the human brain.

With that bigger ambition, Strauss, his flies and his family will move next July from the University of Wurzburg in Germany, where he is a professor of neurobiology, to a new $500 million research facility that the Howard Hughes Medical Institute is building on the banks of the Potomac River in Loudoun County.

He is one of seven group leaders the Chevy Chase-based foundation named yesterday to lead 300 scientists who will work together at the Janelia Farm campus in Ashburn. Their areas of expertise will range across biology, physics, computer science and imaging, but their common aim will be to tackle one of the last frontiers in molecular biology: understanding how brains work. The scientists will try to devise new imaging tools -- and in Strauss's case, seeing robots -- to help with the analysis.

Hughes executives say that the research will be extremely basic in nature and that it could be years, if not decades, before commercial and clinical applications are found.

But Loudoun County officials are banking on the new center to spark economic development in the region and give rise to dozens of biotech, software and medical device companies. Construction is underway, and the facility is slated to open in about a year.

"I'm surprised how much interest there has been from companies even before Janelia Farm is even open," said Larry Rosenstrauch, the county's economic development director. "While we haven't landed a big fish yet, there is a lot of interest there."

That's because companies and investors have an almost genetic desire to locate firms near innovative research hubs. The National Institutes of Health, for instance, helped spawn dozens of biotech companies in Montgomery County. Harvard University and the Massachusetts Institute of Technology did the same for the Boston area, as did Stanford University in the San Francisco area.

"It doesn't happen right away," said Howard Hughes President Thomas R. Cech. "But it will happen at first with a company or two, and that will then snowball with more and more interest. The idea is that they'll be able to work shoulder to shoulder with great science."

Julie H. Simpson, a postdoctoral fellow at the University of Wisconsin, will join Strauss as a group leader. She also is enamored with fruit flies and will bring 8,000 with her. Already, she has developed a preliminary map of neurons that produce seizures, paralysis and other losses of motor control.

"If I didn't believe that this research would have relevance to people, I wouldn't be spending my time on it," Simpson said. "How immediate the results will be, we just don't know. If we could predict what research will produce clinical breakthroughs, we would. But you don't know until you look."

Karel Svoboda, a group leader moving to Janelia Farm from Cold Spring Harbor Laboratory in New York, hopes to help Simpson and Strauss look. He places tiny glass slides in the skulls of mice and then watches neurons fire using sophisticated microscopes he has developed. He looks at the tiny junctions between neurons to see how new connections form when new experiences happen.

"I'm really trying to understand very basic questions," Svoboda said.

Howard Hughes will eventually name 17 more group leaders to direct research at what will be a sort of palace of scientific discovery. Designed by renowned architect Rafael Vinoly, the building is three football fields long and is blended into the side of a hill, encased in glass. Several long staircases give visitors the impression of climbing the hill as they walk up. The sprawling labs are surrounded by trees and gardens. There also will be apartments on campus -- studios and two-bedrooms with fashionable sinks.

But the real attractions for the scientists are less tangible. They will not be segregated into different departments based on what kind of science they do, as is the norm at universities. There will be no teaching duties, no need to apply for grants and little administrative work. The idea was to create a life-science version of Bell Laboratories, the 80-year-old research facility started by AT&T Corp. where transistors and lasers were developed after years of grueling, basic research.

"We want these scientists to follow their instincts," said Janelia Farm director Gerald M. Rubin. "Transistors and lasers weren't discovered at Bell Labs because they would have some effect on AT&T's bottom line in the next quarter."

Such a philosophy is the reason why Simpson will be in fly heaven.

"I'm interested in flies and looking at their brains and their weird behavior," she said. "If I can do that without all the extra pulls on my time, I'll be happier and more productive. That's the goal here: to do the fun stuff. We'll see where it takes us."

Loudoun County officials say the Howard Hughes Medical Institute's Janelia Farm campus in Ashburn has already sparked some interest from businesses.