An Italian drug company, FIDIA Pharmaceuticals, has agreed to give Georgetown University at least $62 million during the next 20 years to establish a research institute to study the working of the brain.

The arrangement, which company and university officials call a "joint venture," is one of the largest so far in a growing number of major investments by companies in university research. Officials said it would be the largest amount from a private source ever received by Georgetown.

In return, FIDIA, which opened an American subsidiary last year, will get first chance at commercial applications from any discoveries, but both company and university officials said any profits would be plowed into further research.

They stressed that there would be no corporate control over publications and research topics, issues which have aroused concern elsewhere that industry financing might limit academic freedom.

"I have been assured that there will be complete academic freedom," said Dr. Erminio Costa, a researcher for the National Institute of Mental Health who has been named the first director of the new FIDIA-Georgetown Institute for the Neurosciences. "This will be basic research on the chemistry and functioning of the brain, independent of whatever the company does for making money with their own drugs . . . . It's a wonderful challenge to continue my research and to be assured of long-term support."

For the past 16 years Costa, a member of the National Academy of Sciences, has been chief of NIMH's Laboratory of Preclinical Pharmacology at St. Elizabeths Hospital. With the pending transfer of St. Elizabeths to the District of Columbia government, Costa said he expects that the laboratory will be dismantled.

Costa, in a telephone interview from London, said he expects to begin work at Georgetown this summer after a final contract for establishment of the institute is signed.

Officials said the neurosciences laboratory that FIDIA has agreed to build and equip on the Georgetown Medical School campus will cost about $8 million. The company will provide $2 million in start-up funds plus $3 million a year, adjusted for inflation, for the next 20 years. The total will range from at least $62 million to about $100 million, said Carl C. Pergler, vice president of FIDIA's American subsidary.

Pergler said the company approached Georgetown to establish the institute because it wanted to locate it near its American office, established in Washington last year, and at a major university that already was doing significant work in the neurosciences.

"We are just entering the American market," Pergler said, "and we would like the visibility and credibility that support of major research in the U.S. would give us."

The company, based near Padua, is the third largest drug firm in Italy.

Dr. John C. Rose, vice chancellor of the Georgetown University Medical Center, said the university was interested in receiving the corporate funds because federal research money "is becoming more difficult to obtain . . . . Dr. Costa had scientific friends at Georgetown. We already are doing work in this field. The FIDIA people want to establish a presence here, so it works out well."

Pergler said the company will channel its money through a new nonprofit foundation, which he heads, called the FIDIA Research Foundation.

He said the governing board of the neurosciences institute will be appointed by both the foundation and the university.

Over the past four years, corporate support for university research has included $70 million from Hoechst, a German pharmaceutical firm, to Massachusetts General Hospital, which is tied to Harvard Medical School, and $1.5 million for human embryo research to the Eastern Virginia Medical School in Norfolk from Serono Laboratories, another drug firm.

Robert Rosenzweig, president of the Association of American Universities, said the arrangements prompted "considerable unease that there would be control of scientific research for profit-making purposes."

"That's quieted down somewhat," Rosenzweig said, "because on the whole those concerns have not turned out in practice. But I don't think we should close our eyes and go to sleep."