If one hypothesis holds true, consciousness can be viewed as a sort of stabilized psychedelic trip.

Several speculative and yet untested hypotheses suggest that endogenous DMT, produced in the human brain, is involved in certain psychological and neurological states. DMT is naturally produced in small amounts in the brain and other tissues of humans and other mammals. Some believe it plays a role in mediating the visual effects of natural dreaming, and also near-death experiences, religious visions and other mystical states. A biochemical mechanism for this was proposed by the medical researcher J. C. Callaway, who suggested in 1988 that DMT might be connected with visual dream phenomena, where brain DMT levels are periodically elevated to induce visual dreaming and possibly other natural states of mind. A new hypothesis proposed is that in addition to being involved in altered states of consciousness, endogenous DMT may be involved in the creation of normal waking states of consciousness. It is proposed that DMT and other endogenous hallucinogens mediate their neurological abilities by acting as neurotransmitters at a sub class of the trace amine receptors; a group of receptors found in the CNS where DMT and other hallucinogens have been shown to have activity. Wallach further proposes that in this way waking consciousness can be thought of as a controlled psychedelic experience. It is when the control of these systems becomes loosened and their behavior no longer correlates with the external world that the altered states arise.

Dr. Rick Strassman, while conducting DMT research in the 1990s at the University of New Mexico, advanced the theory that a massive release of DMT from the pineal gland prior to death or near death was the cause of the near death experience (NDE) phenomenon. Several of his test subjects reported NDE-like audio or visual hallucinations. His explanation for this was the possible lack of panic involved in the clinical setting and possible dosage differences between those administered and those encountered in actual NDE cases. Several subjects also reported contact with ‘other beings’, alien like, insectoid or reptilian in nature, in highly advanced technological environments where the subjects were ‘carried’, ‘probed’, ‘tested’, ‘manipulated’, ‘dismembered’, ‘taught’, ‘loved’ and even ‘raped’ by these ‘beings’. This is most likely due to the setting of where the experiments took place. Many people who use DMT outside of a laboratory never report any of these types of experiences.

Waah! More at wikipedia.