See this study. The blurb:

“New brain published in the journal Scientific Reports sheds new light on how LSD produces its psychedelic effects. The drug resulted in the ’emergence of new type of order in the brain,’ the researchers found. The study used a new mathematical method to analyze brain activity, known as connectome-harmonic decomposition, to examine how LSD caused alterations in consciousness. A connectome is a distinctive pattern of neural connections — like a wiring diagram of the brain.”