In 2016 researchers at the University of Utah conducted tests with 19 returned missionaries, recording fMRI scans of their brains as they evoked spiritual feelings.

Excerpt from the UofU article, This is your brain on God: ¹

“Based on fMRI scans, the researchers found that powerful spiritual feelings were reproducibly associated with activation in the nucleus accumbens, a critical brain region for processing reward.”

“In addition to the brain’s reward circuits, the researchers found that spiritual feelings were associated with the medial prefrontal cortex, which is a complex brain region that is activated by tasks involving valuation, judgment and moral reasoning. Spiritual feelings also activated brain regions associated with focused attention.”

“Religious and spiritual experiences activate the brain reward circuits in much the same way as love, sex, gambling, drugs and music…”

Additional Study

Reward, salience, and attentional networks are activated by religious experience in devout Mormons – http://www.tandfonline.com/doi/10.1080/17470919.2016.1257437