A neurobiological model of the near-experience consists of a "perception of separation from the body" (1). One can sense "moving through a dark space or tunnel" (2). Another feature is hallucinations such as "God as light" and angels (1). Some individuals also claim to hear noises at the beginning of the near-death experience and later encounter "mystical states" which are often peaceful (1).
Near-death experiences can be described as an "altered state of consciousness" due to neuronal activity (1). A "dissociative" drug, ketamine induces the near-death experience and "profound religious experiences" due to mechanisms at the "mind-brain interface" (1-McGuire et al., 1995). Near-death experiences arise from the a blockage of the neurotransmitter, glutamate, by N-methyl-D-aspartate receptors (1). A surge of glutamate, which overactivates N-methyl-D-aspartate, is caused by "low oxygen, low blood flow, low blood sugar, and temporal lobe epilepsy" (1). These experiences also bring about a rush of ketamine-like chemicals which alter consciousness by binding to the cells and prolonging their life (1).
Near-death experiences can be prevented during surgery by the "co-administration of sedatives which produce 'true' unconsciousness rather than dissociation" (1-Reich and Silvay, 1989). However, ketamine when used alone can generate near-death experiences: "'An anaesthetist observed: 'Ketamine allows some to reason that...the strange, unexpected intensity and unfamiliar dimension of their experience means they have died..'" (1-Collier, 1981, p 552).
Ketamine binds to the phencyclidine site of the N-methyl-D-aspartate receptor which in turn influences "cognitive processing, memory, and perception" in the temporal and frontal lobes (1). Moreover, ketamine administration prevents "excitotoxicity", or "brain cell" damage, which is induced by N-methyl-D-aspartate receptors during epilepsy and psychoses (1). Like ketamine, endopsychosines (other chemicals in the brain) bind to N-methyl-D-aspartate receptors where magnesium and zinc ions play significant roles (1).
I agree with the "scientific paradigm" discussed in this paper: "Within a scientific paradigm, it is not possible, that 'the spirit rises out of the body leaving the brain behind, but somehow still incorporating neuronal functions such as sight, hearing and proprioception'" (1-Morse, 1989). Furthermore, if the near-death experience is attributed to a religious phenomenon, we must find a paradigm which encompasses all religions, cultures, and races (1).
The near-death experience sparked my interest during the television program, "Turning Point", which portrayed the controversy between the scientific and religious elements of near-death experiences. "Turning Point" illustrated firsthand accounts of near-death experiences and discussions with esteemed scientists who discredited the religious feeling of the experiences. According to "Turning Point", some hospitals have installed electronic message boards in operating rooms where one can see them only if they are floating like in a near-death experience. However, not a single individual has reported seeing the electronic message boards, which are changed regularly with new messages as stated by "Turning Point".
1. Using Ketamine to Induce the Near-Death Experience: Mechanism of Action and Therapeutic Potential
2. The Near-Death Experience
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