The study, published in Neuroscience Letters, comes from Mario Beauregard, Ph.D., and Vincent Paquette, M.Sc. They work at Canada's University of Montreal.
Other researchers have suggested there might be one key part of the brain involved in spiritual experiences, note Beauregard and Paquette.
To test this theory, the Canadian researchers turned to 15 Carmelite nuns — and to high-tech brain scans.
The nuns were 23-64 years old, with an average age of 50 and average tenure as a nun of almost 20 years.
The nuns set a few ground rules for the researchers.
"The nuns told us before the onset of the study that 'God can't be summoned at will,'" write Beauregard and Paquette.
So the scientists didn't ask the nuns to try to get in touch with God during the brain scans.
Instead, the nuns had their brains scanned as they recalled their most intense mystical experience — defined as a sense of union with God — since joining the Carmelite order.
For comparison, they also got brain scans while remembering their most intense experience with another person since taking their vows, and while simply resting with their eyes shut.
The researchers had asked the nuns to practice summoning up those memories in the week before the brain scans.
The nuns' brain scans didn't show any particular "God spot" of brain activity.
Instead, several brain areas were active while the nuns reflected on their most intense mystical experience. And the activity wasn't identical to that seen when the nuns reflected on interpersonal memories.
The researchers interviewed the nuns after their scans.
Several nuns mentioned feeling peace, God's presence, and God's "unconditional and infinite love" while recalling their most intense mystical experience, the researchers write.
In their research, Beauregard and Paquette weren't trying to prove or disprove God's existence. The study doesn't "confirm or disconfirm the existence of God," Beauregard says in a University of Montreal news release.
SOURCES: Beauregard, M. Neuroscience Letters, Sept. 25, 2006; vol. 405: pp 186-190. News release, University of Montreal.
By Miranda Hitti
Reviewed by Louise Chang, M.D