Dr. Stanislav Grof, M.D., is a psychiatrist and one of the leading researchers into non-ordinary states of consciousness. In Tom Harpur's NDE documentary, Life After Death, Dr. Grof explains a theory of consciousness based on these non-ordinary states. Dr. Grof theorizes consciousness to be nonlocalized and that the brain may instead function as a "reducing valve" minimizing the cosmic energy input bombarding our body. Consciousness then arises as a product of this reducing function of the brain. Whenever the reducing function of the brain is altered (through various triggers such as out-of-body experiences, hallucinogenic drugs, mental psychosis, psychic visions, etc.) or even shut down completely as in NDEs, the reduced cosmic energy input that once made up our consciousness is then free to expand. This expansion of consciousness, in theory, accounts for these various types of mental phenomena and for the many "triggers" altering the reducing valve function of the brain. From the large collection of NDEs on this website, you can see how these triggers are capable of inducing NDE related phenomena.