Ultra-slow mechanical stimulation of olfactory epithelium modulates consciousness by slowing cerebral rhythms in humans.
Scientific Reports April 26, 2018 A Piarulli, A Zaccaro, M Laurino et al.
Periodic odorless air puffs delivered to the olfactory epithelium at 0.05 Hz (8 seconds on, 12 seconds off) in 12 healthy subjects enhanced delta-theta EEG activity across the whole cortex, especially in limbic system and default mode network structures, reversed the direction of information flow from a wake-like posterior-to-anterior pattern to a NREM sleep-like anterior-to-posterior pattern, and produced self-reported altered states of consciousness. The findings suggest a neurophysiological basis for how respiration-based meditative practices may induce altered states of consciousness.