Psychedelic Baby Brain
Some experimenters looked at the brains of people who ave had at least one experience with a psychedelic drug like LSD, magic mushrooms, ayahuasca etc. They gave them a moderate dose of LSD - one hit or blotter of LSD, which is typical when taken recreationally. They screened out people who might have "psychological vulnerability."
They found they had brains much like a baby's brain. Meaning? Babies have emotions go up and down - happy, ecstatic, then crying. The subjects also experienced this, along with emotional sensitivities and hyper-imaginative moments and a childlike sense of wonder and awe about the world.
That might be seen as mystical or spiritual way, or simply the wonder of the very young.
The poet William Wordsworth talked about the infant state as a heavenly state where we're closer to what you might call God.
Listen to an NPR story about this