(September 6, 2008 at 2:38 pm)Mystic Monkey Wrote:(September 6, 2008 at 12:32 am)solidsquid Wrote: Dreaming would require brain function though. Death is the irreversible cessation of all brain function. No brain function, no dreaming. Any "dream like" subjective state would be experienced in the few minutes to seconds before death. Some posit that the "tunnel of light" is a result of hypoxia on the brain - visions of a dying brain. They are a common report in NDEs. Also OBEs (out of body experiences) are often reported. This is found as a consequence of the breakdown of the parietal spatial filter and has been replicated in the laboratory.
How can their be "visions" of a dying brain if it's really a matter of hypoxia? That be like our eyes going inside our head to see hows our brains doing. Sure without brain function their will be no actual dreams but also remember that time spent dreaming varies compared to our actual timing, Im just seeing it on a bigger yet still logical sense.
By “visions”, I meant what is reportedly seen by these people is a product of a dying brain.
G.M. Woerlee (2004), an anaesthiologist, quickly describes what happens during incidents leading to oxygen deprivation or starvation to the brain:
Quote:During NDEs caused by oxygen starvation, a combination of brain malfunction, abnormal muscle spindle function, random movements due to convulsions caused by oxygen starvation, and movements of the oxygen-starved person’s body made by people treating and helping the person all combine to generate sensations of movement. When this is combined with a total loss of vision, tunnel vision, or the effects of pupil widening, sensations of moving through darkness or a tunnel toward light can occur. Some people also say they felt themselves being “drawn to the light.” This is quite possibly a result of the initial restoration of central vision, followed by an increasing restoration of peripheral vision as oxygen supplies to the eyes increase. A person undergoing such an experience would first see a small spot of light at the end of a tunnel which would gradually increase in size to envelop the whole visual field. This would give the illusion of moving toward a light at the end of a tunnel, and even of entering the light as retinal function was restored.
It has also been shown that the NMDA receptor complex seems to play a key role in NDEs as well having a central role schizophrenia and dissociative anaesthia (Bonta, 2004). Studies with the drug ketamine have been shown to reproduce the phenomena in NDEs as well (Jensen, 1996; Jensen, 1997; Reich & Silvay, 1989) by acting upon NMDA receptors and blocking activity.
If anything, it’s more of a dissociative, hallucinatory state rather than “dreaming”.
References:
Bonta, I. (2004). Schizophrenia, dissociative anaesthesia and near-death experience; three events meeting at the NMDA receptor. Medical Hypotheses, 62, 23-28.
Jensen, K. (1996). Using Ketamine to Induce the Near-Death Experience: Mechanism of Action and Therapeutic Potential. Yearbook for Ethnomedicine and the Study of Consciousness (Jahrbuch furr Ethnomedizin und Bewubtseinsforschung), 4, 55-81.
Jensen, K. (1997). The Ketamine Model of the Near-Death Experience: A Central Role for the N-Methyl-D-Aspartate Receptor. Journal of Near Death Studies, 16, 5-26.
Reich, D. & Silvay, G. (1989). Ketamine: an update on the first twenty-five years of clinical experience. Canadian Journal of Anesthesia, 36, 186-197.
Woerlee, G. (2004). Darkness, tunnels and light. Skeptical Inquirer, 28, 28-32.
