Andrew Newberg attracted a small crowd to his talk at the Penn Bookstore over a lunch hour last month. With a click of his laptop’s mouse, he projected a picture of the human brain onto the wall behind him. The brain rotated in space. Different areas of the brain were highlighted in different colors.

But Newberg, a radiology professor who conducts research on spiritual experiences, was not presenting an ordinary neuroscience lecture. People with religious convictions, people in recovery, professors, staff members and community members all gathered with a shared curiosity about his latest findings.

His new book, co-written with professor of psychiatry Eugene d’Aquili, who since has died, is called “Why God Won’t Go Away: Brain Science and the Biology of Belief.”

The research in this book gives us a neurological snapshot of intense spiritual experiences, pinpointing which areas of the brain are involved in how we perceive and react to religion.

Newberg’s latest research involves people who meditate in the Tibetan Buddhist tradition. In interviews, the Buddhists said that meditation often gave them a feeling of oneness with the universe —a loss of the sense of self.

To get a glimpse of how these feelings look in the brain, Newberg injected small amounts of radioactive material into the meditators’ bloodstreams as they reached their meditative peak. This injection let Newberg see how much blood was flowing to each section of the meditators’ brain during that peak experience.

Newberg’s most interesting finding concerns a part of the brain called the parietal lobe, also known as the orientation area. This area normally helps us create a sense of the self and helps us orient that self in space.

During meditation, the blood flow to the subjects’ orientation areas decreased significantly, indicating a drop in activity. “The meditators are progressively blocking the sensory input that goes into the orientation area,” Newberg said. “Even though it’s still trying to create that sense of the self, it has less and less data on which to work.”

The limbic system of the brain, which is responsible for emotions, got more blood than usual during meditation. This might account for meditators’ reported feelings of bliss or ecstasy, he said.

At his talk in the Penn Bookstore, Newberg emphasized that he isn’t trying to say religious experiences are all in people’s heads.

“If you eat an apple pie, it creates certain responses in your brain,” he said. “But a neuroscientist can’t tell by looking at those responses whether or not the pie is really there.”

Similarly, showing what a perceived communion with God looks like in the brain doesn’t necessarily mean God isn’t there. Science, Newberg said, can never determine whether the brain created God or God created the brain.

“For whatever reason, our brain enables us to have religious and spiritual experiences relatively easily,” he said. “If you are a believer you might say that since God exists, it makes sense for us to have a brain that enables us to have contact with God. But it also could be that the brain evolved to help us solve problems and order our world, and religion became a powerful way of helping us do all that.”