It's common to hear users of psychedelic drugs describe trips on mushrooms or LSD as a "spiritual experience," and the comparison is nothing to scoff at, according to neuroscientist Andrew Newberg.

HuffPost Live continued its week-long exploration into the connections between drugs and religion on Wednesday when host Josh Zepps spoke with Newberg, the director of research at Philadelphia's Jefferson Myrna Brind Center of Integrative Medicine, about his research into how the brain responds to stimulus like prayer and drugs.

Newberg explained one study that examined the brains of nuns who engaged in "centering prayer," which is meant to create a feeling one oneness with God. The nuns' brain scans showed similarities to people who use drugs like psilocybin mushrooms, Newberg said, and both experiences "tend to result in very permanent changes in the way in which the brain works."

Some argue that a feeling of spiritual connectivity achieved through drugs is "artificial" compared to nuns who experience the same thing without chemicals, Newberg said, but he's open to the parallels between them.

"I always use the analogy about me wearing glasses: When I wake up in the morning, it's a very fuzzy world. I put my glasses on and I see the world clearly," he said. "It's possible these kind of experiences [with drugs] are not artificial or false, but really enable a person and a person's brain to experience the world in a much more fundamental way."

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