In an unusual marrying of science and spirituality, the Dalai Lama addressed thousands of the world's top neuroscientists yesterday, telling them that society is falling behind in its efforts to make sense of their groundbreaking research.

Speaking sometimes in Tibetan and sometimes in halting English to a receptive audience at the 35th annual meeting of the Society for Neuroscience, the Tibetan spiritual and political leader said scientists and moral leaders need each other.

"It is all too evident that our moral thinking simply has not been able to keep pace with such rapid progress in our acquisition of knowledge and power," he said in a prepared text.

The speech at the Washington Convention Center had been opposed by some members of the society who objected to a religious leader addressing neuroscientists, who research the brain, emotions and human behavior. Nearly 800 people had signed an online petition demanding that the Dalai Lama's invitation be withdrawn.

Many of the petition signers were Chinese Americans, leading to countercharges that they opposed him on political grounds. Relations between China and once-independent Tibet have been badly strained for a half-century, and the Dalai Lama is at the center of the dispute.

But except for minor protests yesterday -- one woman held a sign that read "Dalai Lama not qualified to speak here" -- that conflict was barely visible at the conference. Some attendees stayed away from his talk, and others left early in what a few described as a protest of sorts.

For most of the 14,000 conference participants who watched in the lecture hall or from overflow rooms, the Dalai Lama's enthusiastic embrace of science and promotion of meditation were warmly received. His 10-day visit to Washington, which included a meeting with President Bush last week, will continue today at MCI Center, where he is scheduled to give a public talk on "Global Peace Through Compassion."

The author of a new book on the convergence of Buddhism and science, the Dalai Lama has met with prominent scientists around the world for almost 20 years and has encouraged an increasingly fruitful collaboration between brain researchers and Tibetan monks.

Because of the controversy over his speech to the neuroscientists in Washington, his aides said he would keep to a prepared text, something quite unusual for him. But he often diverged from the text, despite saying with a smile that he was feeling unusual "stress."

His talk focused on how he developed his interest in science as a boy in Tibet, within a closed and isolated society, and on his view that morality and compassion are central to science. He pointed out in his prepared text, for instance, that although the atom bomb was great science, it created great moral problems.

"It is no longer adequate to adopt the view that our responsibility as a society is to simply further scientific knowledge and enhance technological power and that the choice of what to do with this knowledge and power should be left in the hands of the individual," he said.

"By invoking fundamental ethical principles, I am not advocating a fusion of religious ethics and scientific inquiry. Rather, I am speaking of what I call 'secular ethics' that embrace the key ethical principles, such as compassion, tolerance, a sense of caring, consideration of others, and the responsible use of knowledge and power -- principles that transcend the barriers between religious believers and nonbelievers, and followers of this religion or that religion," he said.

He acknowledged that some might wonder why a Buddhist monk is taking such an interest in science.

"What relation could there be between Buddhism, an ancient Indian philosophical and spiritual tradition, and modern science?" he said. His answer was that the scientific empirical approach and the Buddhist exploration of the mind and world have many similarities.

In the Tibetan Buddhist tradition, however, the Dalai Lama is known as the reincarnation of a major force for compassion, and his strongest words yesterday were directed at religious people who might lack that trait.

"People who call themselves religious without basic human values like compassion, they are not really religious people," he told the audience, offering no names. "They are hypocrites." The words were unusually critical for a speaker who likes to emphasize the positive and productive.

The single protester outside his follow-up news conference at the convention center was Pei Wang, a neuroscience graduate student at the State University of New York at Buffalo. "This is supposed to be a scientific talk," she said. "If he is not presenting data, he should not speak. This should be about research, not about some politician giving a speech."

The Society for Neuroscience annual meeting, which will continue through Thursday and has attracted 31,000 people, features scores of papers on research into human behavior.

In keeping with the Dalai Lama's involvement with meditation and the physical and mental implications of the contemplative life, one of the higher-profile papers reports on how regular meditation appears to produce structural changes in areas of the brain associated with attention and sensory processing. An imaging study led by Massachusetts General Hospital researchers showed that particular areas of the cerebral cortex, the outer layer of the brain, were thicker in participants who were experienced practitioners of a type of meditation commonly practiced in the United States.

"Our results suggest that meditation can produce experience-based structural alterations in the brain," said Sara Lazar of the hospital's Psychiatric Neuroimaging Research Program and lead author of the study, which will appear in the journal NeuroReport. "We also found evidence that mediation may slow down the aging-related atrophy of certain areas of the brain."

In the text for his speech to the Society for Neuroscience at the Washington Convention Center, the Dalai Lama said moral thinking "has not been able to keep pace with such rapid progress in our acquisition of knowledge and power."Some neuroscientists objected to the speech by the religious leader.