Consciousness Beyond Life: The Science of the Near-Death Experience (26 page)

I would like to offer some additional comments on Pamela Reynolds’s NDE and the medical circumstances under which she had her experience.

The kind of brain surgery that she underwent lasts at least four to six hours, just as long as heart surgery. While she was under general anesthesia and surgery on her skull had begun, but her body had not yet significantly cooled down and the blood had not yet been removed from her head, she had an out-of-body experience. She was able to see and hear a great many details despite the fact that she was under general anesthesia, her eyes had been taped shut, and small speakers emitting loud clicks had been inserted into her ears. She could see the equipment and the people in the operating theater; she could see the instrument with which her skull was opened up. During the operation she could hear the conversation between Spetzler and the female cardiovascular surgeon operating in her groin to link her up to the heart-lung machine. When the cardiovascular surgeon made an incision in her right groin, she found that Pamela’s veins and arteries were too small, so she had to switch to the left groin. The doctors had a brief exchange on this matter. Pamela heard these remarks and repeated them word for word. After her out-of-body experience, she was pulled into a tunnel. The rest of her NDE, which included an extremely lucid consciousness, the recognition of and communication with deceased relatives, and an encounter with the light, took place during a time when induced hypothermia and anoxia (no oxygen due to lack of blood) had rendered her brain completely nonfunctional. Some time into the operation, the hypothermia induced a cardiac arrest, which is why Pamela had to be connected to the heart-lung machine. Once her body had cooled down to 10 degrees C (50 degrees F) and had been linked to the heart-lung machine, the top of the operating table was raised briefly to remove all the blood from the brain. All these measures were necessary for the operation on the aneurysm to have any chance of success.
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Few medical centers in the world would be prepared to carry out such a risky procedure. Extreme hypothermia enables the brain cells to survive for a maximum of sixty minutes during an operation of this kind. The low temperature slows the cellular metabolic rate to such an extent that the brain cells can remain in the pilot-light state for longer without dying. Toward the end of her NDE, Pamela had another out-of-body experience while she remained under general anesthesia, her eyes were still taped shut, and she was still in cardiac arrest. She saw her body jump, which was the result of the electric shock (defibrillation) that was administered to get her heart going again. This only happens once the operation has ended and the body has been warmed up. She felt a chill upon returning to her body because it had not yet reached its normal temperature of 98.6 degrees Fahrenheit.

The prospective NDE studies showed that an enhanced and extremely lucid consciousness can be experienced during a cardiac arrest. We know from other studies that during a cardiac arrest the cerebral cortex and brain stem show no measurable activity while the clinical picture shows a complete loss of all brain function. To our utter surprise, we were forced to conclude that oxygen deficiency alone does not explain the experience of an enhanced consciousness. If an NDE arose in response to oxygen deficiency in the brain, all patients in the Dutch study should have reported one. Nor did the severity of the medical situation, such as a lengthy coma after a complicated resuscitation with prolonged oxygen deprivation, explain whether or not patients reported an NDE. Near-death experiences also take place under circumstances that do not involve oxygen deficiency.

These findings made me all the more curious about brain function under normal, everyday circumstances. How can we reconcile the experience of an NDE during the loss of all brain function with our commonly accepted ideas about brain function? What do we know about the way our brain functions, and how do we know this? What theories do we have about the relationship between the brain and consciousness? I will consider these questions in more detail in the next chapter.

I am well aware that this chapter may not be easy for everyone. But my exploration of the anatomy, function, and imaging techniques of the brain is aimed at improving our understanding of the complexity of the brain while at the same time recognizing how little we still know about brain function and the origins of consciousness. Most neuroscientists take a materialist approach, which is based on the premise that the content of thoughts, feelings, and memories can be accounted for on the basis of measurable brain activity. However, the hypothesis that consciousness and memory are produced and stored exclusively in the brain remains unproven. There is no direct evidence to prove if and how neurons in the brain produce the subjective essence of our consciousness. This chapter will draw on scientific studies to prove that the materialist approach falls short in many respects and can no longer be maintained in its current form. It is now becoming increasingly clear that brain activity in itself cannot explain consciousness.

The Search for Consciousness

The previous chapters revealed that people can experience a clear consciousness with memories, lucid thoughts, and emotions during a cardiac arrest. But a period of clinical death, precipitated by the loss of blood flow to the brain, is characterized by the absence of all measurable and clinical brain activity. How can this be? What does science tell us about the relationship between the brain and consciousness, and where and how can consciousness be localized in the brain? How can matter produce consciousness? After all, the brain is made up of pure matter, of atoms and molecules, which in turn are the building blocks of cells with chemical and electrical processes. Composed of “unconscious building blocks,” the brain is certainly capable of facilitating consciousness. But does the brain actually “produce” our consciousness? And where in the brain can this consciousness be produced and stored?

Another question is how a nonmaterial activity such as mindfulness or thinking corresponds with a visible reaction in the form of measurable electrical, magnetic, and chemical activity in a certain part of the brain. These activities can be measured with the help of (1) an electroencephalogram (EEG), which registers the electrical activity in the cerebral cortex, or with (2) a magnetoencephalogram (MEG), which registers the brain’s magnetic activity. Differences in activity are measured (indirectly) with (3) functional magnetic resonance imaging (fMRI), which can map differences in the brain’s blood flow because blood contrasts with surrounding tissue. The scan produces a blood-oxygen-level dependent (BOLD) contrast, which indirectly reflects the metabolic activity of neural networks. It does not register neural activity directly. Brain activity can also be registered with the help of (4) a positron emission tomography (PET scan), in which an injected radioactive substance can provide more direct information about differences in the metabolic activity of brain cells. It is possible to measure a 30 percent increase in blood flow to the brain during thinking or mindfulness because the neurons use more energy for such processes.
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All of these forms of research measure changes in blood flow and activity at certain locations in the brain. These activities may vary for individual subjects while changing thoughts and emotions also activate new locations. While this suggests that neural networks play some role in the manifestation of thoughts, feelings, and memories, it does not necessarily imply that these cells actually produce and store our thoughts and emotions. We have no direct evidence to prove if and how neurons in the brain produce the subjective essence of our consciousness. What we do know is that the following three structures and the close connections between them enable us to experience consciousness: (1) the ascending reticular activating system (ARAS) in the brain stem; (2) the cerebral cortex, especially the frontal lobe, temporal lobes, and parietal lobes; and (3) the connections between the cortex and the stem, by way of the thalamus and the hippocampus (see figure). These centers show distinct activity during consciousness, and impairment of these centers leads to unconsciousness or coma. The logical conclusion is that collaboration between these brain centers plays a role in enabling the experience of everyday (waking) consciousness.
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The anatomical structures in the brain.

The anatomical structures in the brain. Illustration by Maura Zimmer.

The Reliability of Contemporary Brain Research

How accurate is contemporary brain research? Which brain activities can be measured, what causes these activities, and what do these measured activities tell us about what actually happens in the brain? And of course we must ask ourselves what it means if we can no longer measure any of these activities in the brain.

An fMRI (see figure) shows blood flow activity in the brain at a resolution of approximately a grain of rice (a “voxel”). Millions of neurons must be fired simultaneously to illuminate such a small region. An fMRI cannot be used to determine the sequence of, and hence the connections between, the measured activities in the various regions. The fastest possible speed is currently only one scan per two seconds, which is far too slow to trace and map cerebral processes that take place in mere milliseconds. This could be compared with reading a book by reading only one of each thousand words.

MRI of the brain.

MRI of the brain. Image © Larry Mulvehill/Corbis.

At present, scientific research methods appear to be incapable of accurately studying the neural processes associated with our experience of consciousness. If changing forms of cooperation between large groups of neurons are indeed the neural correlates of consciousness, our current research techniques are not up to the task of mapping this process. Even the most modern and detailed fMRI scan shows us no more than the physical basis of an observation or of mindfulness and fails to offer any explanation for what happens in our mind. Besides, an fMRI scan says nothing about the content of our thoughts and feelings. It is alarming therefore that fMRI research has prompted some scientists to trace a causal link between certain brain functions and specific mental processes.
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This concern is shared by the Danish neuroscientist and anthropologist Andreas Roepstorff in a recent interview.
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The interviewer noted that “Roepstorff has a difficult message for his peers”: “Complete, objective knowledge about the nature of the human mind is impossible, despite all brain scans.” Roepstorff describes his experiences as a volunteer in an experiment. As part of this experiment, subjects were placed in an fMRI scanner and had the soles of their feet tickled. Sometimes they could only feel the tickling, and sometimes they could also see it happening in a mirror. The experiment sought to identify differences in the way the brain processes information. But Roepstorff was annoyed by the experiment leader, who for no apparent reason left him in the scanner for a very long time. He decided to play a trick on the leader. If he was tickled, he would think about football, but if he could also see himself being tickled, he would think about his cat’s funeral. He comments: “Because I was thinking about different things the brain scans should, in theory, have shown activity in different parts of the brain.”

Given the fact that Roepstorff’s thoughts fell outside the scope of the experiment, the test leader should not have been able to understand the findings. But the leader failed to notice anything strange about the scans. They were no different from the scans of any of the other subjects.

In fact, Roepstorff is curious to know whether in five to ten years’ time we may have to concede that we were stupid to think that we could explain us to ourselves by way of the brain.

Both Roepstorff and neuropsychologist Anthony I. Jack are convinced that it is impossible to produce objective evidence with which to test the reliability or veracity of subjective reports.
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The same applies, in their view, to psychological research techniques. The fact that specific parts of the brain are activated and thus involved in specific tasks does not seem to explain cognitive processes. When researching the structure of information processes in the brain, psychologists are not allowed to use reports on thoughts and feelings in the same way as objective reports on behavior. But Roepstorff and Jack also reject the assertion that the accuracy of reported thoughts and feelings must always be called into question. They believe that there should be room for faith in reported ideas and emotions, provided of course that the subject has been proven to be reasonably reliable. Needless to say, the same applies to the subjective reports of near-death experiences, the subject of this book.

In their scientific publications Jack and Roepstorff write that the validity of the conclusions drawn from registrations of brain activities is both the most important and theoretically most complex and thorny subject in the cognitive sciences. A measurement is deemed reliable only if there is evidence that it accurately reflects the phenomenon it set out to examine. Reliability is all the more complex because scientific measurements are often used to prove phenomena straddling entirely different levels. By
different levels
they mean which aspects or conclusions of measurements have definitely been proven, which may have been proven, or which are unlikely.
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They clarify this with a few examples:

Evidence has shown that the results of fMRI scans can be used to track blood flow in the brain. But these scans do not yet allow positive conclusions about neural activities because scientists are still in the process of establishing these activities with some degree of accuracy. Besides, an fMRI scan probably says (almost?) nothing about the content and location of cognitive functions because these have not yet been established with any degree of certainty.


Measurements of observed behavior, such as the measurements of reaction times, are valuable as direct proof of stable behavioral patterns but less valuable for assessing the development of information processes, and least of all as proof of the existence and mechanism of certain cognitive functions.


Reports of subjective thoughts and feelings serve primarily as proof of people’s ideas about their own experience but are less direct proof of the existence of experimentally induced phenomena, while reports of subjective experiences cannot provide any direct proof of the origins of specific cognitive functions.