A blogger on another site wrote: "...[a blog at] Scientific American, explain[s] all the different phenomena associated with near death experiences (NDEs) from a neuroscience and physiology point of view, from tunnel vision to seeing bright lights, feeling that your 'soul' has left your body, and that you are dead. Nothing paranormal or spiritual about it of course. The blog covers a paper recently published in the journal Trends in Cognitive Science, with the cute title: 'There is nothing paranormal about near-death experiences: how neuroscience can explain seeing bright lights, meeting the dead, or being convinced you are one of them.'
"Reading the full article requires a subscription but the abstract is free. The summary is that NDEs are the reaction of a normal brain to traumatic (and sometimes harmless) events. I did not know that actually 30% of people who experience an NDE were never in risk of dying, for example. Out-of-body experiences for example, happen to as many as 40% of people during certain sleep patterns, known as sleep paralysis; these out-of-body experiences can be purposely induced by stimulating a precise region of the brain, the temporoparietal junction. Also, abnormal function of dopamine pathways can provoke hallucinations such as ghosts or monsters (reported by people with Parkinson's disease, for example)...."
I had OBE'S at one time in my life. I thought they were psychic experiences, but I eventually came down from my high.
I've read OBE's are easily attributable to retinal and cerebral anoxia.