Consciousness Beyond Life: The Science of the Near-Death Experience (19 page)

The production of DMT is stimulated by the adrenocorticotropic hormones cortisol, epinephrine (or adrenalin), and norepinephrine (or noradrenaline). These hormones are also found in the brain. During major psychological or physical stress, such as a traffic accident, a cardiac arrest, or acute pain, the body releases large quantities of these adrenocorticotropic hormones, which in turn activate a large amount of DMT. During the process of dying, large quantities of DMT are thought to be released by the death of cells in the pineal gland. During deep meditation, however, normal bodily function changes; serotonin levels and probably also DMT levels in the blood increase while cortisol and epinephrine (or adrenaline) levels drop.
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The experience induced by psychoactive substances is often surprisingly similar to a near-death experience, especially in the case of DMT although, depending on the dosage, confusing or frightening perceptions may also occur. These substance-induced experiences include the following elements: a sense of detachment from the body, out-of-body experiences, lucid and accelerated thought, an encounter with a being of light, a sense of unconditional love, being in an unearthly environment, access to a profound wisdom, and wordless communication with immaterial beings. Sometimes the characteristic post-NDE transformation, including the loss of the fear of death, is also reported after administration of DMT or LSD.
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It is a new and surprising hypothesis that DMT, which occurs naturally in the body, could play an important role in the experience of an enhanced consciousness during near-death experiences. Perhaps DMT, its release triggered or stimulated by events in our consciousness, lifts our body’s natural inhibitions against experiencing an enhanced consciousness, as if it is able to block or disrupt the interface between consciousness and our body (and brain). Mention should be made here of the fact that zinc is essential for the synthesis of serotonin and related substances such as DMT. At a more advanced age, the body has lower levels of this metal, and, as mentioned earlier, NDE reports are less common at an older age.

Electrical Activity of the Brain

Epilepsy

An epileptic seizure is characterized by a kind of electrical storm, a short-circuit, which wipes out the electrical (and magnetic) activity in a certain area of the brain. As a result, normal activity of the brain cells (neurons) is blocked in that part of the cerebral cortex where the epileptic seizure originated. An epileptic seizure that originates in an area of the brain close to the temporal bone, the temporal lobes, may trigger muddled observations, mystical feelings, déjà vu experiences, a sense of detachment from the body, and olfactory (smell) or visual hallucinations. Sometimes these seizures are accompanied by unconsciousness or involuntary movements. After such an epileptic seizure of the temporal lobe, most patients have no memory of what happened to their bodies. They only remember what happened in their minds.

On the basis of these data some researchers have proposed a link between the near-death experience and either an increased activity or the cessation of all activity in the brain’s temporal lobes. But studies with both superficial and deeper electrodes show that the symptoms of temporal lobe epilepsy are caused by underlying (limbic) structures and not by the cerebral cortex itself. A detailed study among epilepsy patients also shows that the characteristic elements of an NDE are rarely mentioned after an epileptic seizure of the temporal lobe.
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Some elements are quite similar to an NDE, but déjà vu experiences are also frequently mentioned by healthy people. Needless to say, temporal lobe epilepsy cannot explain an NDE precipitated by fear, depression, or isolation.

Stimulation

Debate about the role of the cerebral cortex in extraordinary experiences in our consciousness has been intensified by studies in which epilepsy patients are subjected to electrical or magnetic stimulation of the cerebral cortex. We know that local electrical stimulation, which is usually applied during brain surgery, results in an inhibition or blockage rather than a stimulation of the affected part of the cerebral cortex. This happens because the stimulation, like an epileptic seizure, wipes out the brain cells’ electromagnetic field. The effect depends on the duration and intensity of the electrical energy administered.

Some researchers claim that stimulation can trigger an out-of-body experience. Through local electrical stimulation of the temporal and parietal lobes during brain surgery for untreatable epilepsy, neurosurgeon Wilder Penfield occasionally managed to evoke memory flashes (never a life review); experiences of light, sound, or music; dreamlike experiences; and once an incipient out-of-body experience, during which a patient indicated, “Oh, God! I am leaving my body.” Although he treated many hundreds of patients over the years, no real out-of-body experience with verifiable perception ever occurred and no transformation was ever reported. The effect of this stimulation was, in many respects, quite unlike an NDE.
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In 2002 neurologist Olaf Blanke described a female epilepsy patient who, after electrical stimulation (blockage), had an incomplete out-of-body experience with a distorted view of only her lower legs. The title of his article in
Nature
suggested that he had managed to locate the place in the brain where out-of-body experiences originate. The article received extensive press coverage and caused quite a (premature) stir. In an article in 2004 Blanke produced another possible neurological explanation for out-of-body experiences.
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He described six patients, of whom three had an atypical and incomplete out-of-body experience—that is, without perception from the ceiling with verifiable elements of themselves or their surroundings—and four patients with an autoscopy, who saw their own double from the vantage point of their own body. In his article Blanke describes an out-of-body experience as an “illusion” caused by the temporary dysfunction or impairment of the temporal and/or parietal lobes. An illusion is an apparent reality or a false sense of reality whereas an out-of-body experience involves a verifiable perception—from a position outside and above the body—of a resuscitation, traffic accident, or operation and of the surroundings in which these took place. An observation with verifiable aspects is, by definition, not an illusion.

As far as we know, not one of the thousands of stimulated epilepsy patients around the world has ever reported a genuine out-of-body experience. The fact that in a single case, as described by Blanke, an abnormal bodily experience was reported does not warrant comparison between this stimulated or impaired area in the brain of an epilepsy patient and the brains of normal individuals. Generalizing this finding seems more than unjustified. Given the fact that none of Blanke’s small number of patients ever showed damage or dysfunction in exactly the same area, we cannot cite the effect of stimulation of a certain area of an epilepsy patient’s brain as evidence that this specific area actually causes the effect.

Similarly, transcranial magnetic stimulation (TMS), in which magnetic fields are aimed at certain parts of the brain, sometimes precipitates experiences in the mind caused by blockage (or stimulation) of electromagnetic fields in the brain. The neuropsychologist Michael Persinger has carried out many of these experiments, and he believes that the reported experiences resemble an NDE. However, closer inspection of his articles disproves this. The reported experiences, such as dreamlike, semimystical episodes with light or music, or the sense of somebody’s presence, bear only a vague resemblance to the elements of an NDE. Suggestibility (that is, a placebo effect) appears to be the overriding factor in these reported experiences because Persinger also reports experiences in 33 percent of people without magnetic stimulation and because a double-blind control of his research in Sweden failed to corroborate his results.
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The Swedish researchers had not informed the participants beforehand why, if, and when they would receive magnetic stimulation.

The EEG and Sleep Disorders as a Result of an NDE

As part of a recent study among people who had an NDE in the past, an EEG (measuring electrical activity in the brain) was made during sleep.
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The rapid eye movement (REM) phase is the phase of sleep in which people dream. Patients with an NDE were found to have fewer periods of REM sleep than a control group without an NDE. The EEG also found anomalies in the left temporal lobe and symptoms of temporal lobe abnormalities, such as unusual visual, auditory, or olfactory experiences, but these are unlike the experiences that are reported during NDE (see also the section about epilepsy in this chapter). The NDErs also experienced a different pattern of sleep. However, the patients in this study were studied only
after
their NDE, which precludes a comparison with the EEG and sleep pattern
prior
to their experience.

Another study also found REM sleep pathologies after an NDE.
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This study looked at the frequency of so-called REM intrusion. REM intrusion is accompanied by a sense of paralysis and confusing perceptions (hallucinations) at the onset of sleep. The content of these perceptions do not resemble an NDE. A higher percentage of these symptoms (42 percent) was found in a self-selected group of people who had had an NDE in the past than in a control group that had been recruited among hospital staff and that reported a much lower percentage of REM abnormalities (7 percent) than is common among the general public (20 to 30 percent). The study’s conclusion that the brain disorders that underpin REM intrusion may also precipitate NDE is, at best, premature for several reasons. The study was poorly designed; nearly 60 percent did not report REM intrusion after an NDE; and patients were examined only after and not before their NDE.
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These studies therefore do not warrant any conclusions about either a neurological basis of an NDE or abnormal brain activity prior to an NDE. We can conclude only that compared to a control group without NDE, people with an NDE have a verifiably different sleep pattern, coupled with EEG anomalies in the temporal lobe. Perhaps the physical and psychological transformation that takes place after an NDE can shed a new light on the registered changes in electrical activity in the brain.

Reviewing the physiological approaches described above, we can conclude that most of them fail to offer an adequate explanation because they are based on:

Physiological causes, such as anomalies or disorders in blood gases, in chemical or electrical brain activity, or at specific locations in the brain, for which there is no or insufficient evidence that they play a role in the origins of an NDE; and/or


Effects that are not or not entirely consistent with the typical NDE elements, especially the most striking and distinctive elements such as out-of-body experiences with verifiable perception, a panoramic life review, or an encounter with deceased persons.

By contrast, research into the effects of psychoactive substances such as DMT has found some striking similarities with NDE elements. It is a new and surprising hypothesis that DMT, which occurs naturally in the body, could play an important role in the experience of an enhanced consciousness during NDE. Perhaps DMT lifts the body’s natural inhibitions against the experience of an enhanced consciousness.

Psychological Theories

Fear of Death

It is of course possible that in life-threatening situations people consciously or subconsciously evoke an experience to escape the fear of imminent death. In such a case, stress triggers a defense against (or a flight from) such imminent death. Another possibility may be stress-induced wishful thinking based on cultural and religious expectations. As mentioned earlier, elements of an NDE are sometimes experienced in life-threatening situations; this is known as a fear-death experience.

Expectations

An article from the 1930s describes experiences that were triggered by critical circumstances and that may have met certain expectations. These experiences were called “shock thoughts and fantasies” and were believed to be invoked as a defense mechanism against mortal danger. The fact that some NDE elements are phrased in religious or cultural terms could be seen as evidence of such expectations. Research has shown differences in the incidence and content of some NDE elements between people in the West and the native peoples of the Americas and Australia, while in India differences have even been found between people from the north and south of the country.
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But for many people the content of an NDE does not match their prior expectations of death. Their experiences are identical, irrespective of whether they believe that death is the end of everything or whether they believe in life after death. Children experience the same elements as adults. Prior knowledge of NDE does not affect the incidence or content of the experience, nor has its content changed since the publication of Moody’s first book on the subject in 1975.
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Depersonalization

Depersonalization refers to the phenomenon of identity loss, coupled with a sense of detachment, alienation, and unreality. People are divorced from the world and their own identity and feel that life is unreal or like a dream. The condition is often accompanied by unpleasant emotions, fear, panic, or emptiness. Out-of-body experiences are never reported in such cases. Depersonalization, which is particularly common among young adult women, allows people to completely disconnect from their surroundings.