by D. F. Swaab
There are no scientific grounds for Van Lommel’s peculiar theory, whereas brain research perfectly explains all aspects of NDEs. An out-of-body experience can be triggered by stimulating the place where the temporal lobe and the parietal lobe meet. If the processing of information from the muscles, the organ of balance, and the visual system is disrupted at the spot where the temporal lobe and the parietal lobe meet—the angular gyrus (fig. 28)—you get the sensation of leaving your body and floating around. Similar experiences have been generated by cannabis use, which influences a great many chemical messengers in the brain. In one patient’s case, electrical stimulation at the rear of the hypothalamus near the fornix (fig. 26) had the side effect of activating the medial temporal lobe, causing him to reexperience events that had taken place thirty years earlier (see chapter 11) and creating the NDE-like effect of his life flashing past. This area is involved in storing the episodic autobiographical memories that form the chronicle of our lives. It is, moreover, extremely sensitive to lack of oxygen and therefore can be easily activated. Stimulating the hippocampus provokes extremely clear, highly detailed autobiographical memories, including memories of people who have died. When one’s life is in acute danger it appears that all of these memories are retrieved not one after the other but virtually simultaneously, leading to what is called “panoramic memory.” As we know from temporal lobe epilepsy and other situations in which the temporal lobe is stimulated (see chapter 15), this can go hand in hand with strong spiritual or religious feelings. People feel that they are one with the universe, the world, or God, or they think that they have gone to heaven or the afterlife and are in direct contact with God, Jesus, or some other religious figure. The feeling of tranquility and the absence of pain in NDEs is ascribed to the release of opiates or stimulation of the brain’s reward system. The vision of a tunnel is caused by reduced blood circulation in the eyeball, starting on the periphery of the field of vision. The periphery grows dark while the center of the visual field remains clear, creating the impression of a tunnel with light at the far end. Fighter pilots trained in a giant centrifuge that impaired blood circulation in their eyes also saw such tunnels. The bright, attractive colors and the beautiful light at the end of the tunnel are caused by stimulation of the visual cortex, just as when we dream. And just as in a dream, a person experiencing an NDE finds themselves taking part in a bizarre story.
FIGURE 28. An out-of-body experience can be induced by stimulating the place where the temporal lobe (which is very susceptible to oxygen deficiency) and the parietal lobe meet: the angular gyrus. If the processing of information from the muscles, the organ of balance, and the visual system is disrupted at this location, you get the sensation of leaving your body and floating about.
Van Lommel’s theory boils down to our brains and our DNA being receivers for “waves of consciousness,” a term that he doesn’t go on to define. In his explanations he frequently uses terms like entanglement, nonlocality, and other terms borrowed from quantum mechanics. The theoretical physicist Robbert Dijkgraaf, president of the Royal Netherlands Academy of Arts and Sciences, better qualified than I to pronounce on questions of physics, is clear in his opinion. “When faced with the inexplicable, people like to believe that quantum mechanics must provide the answer. But unfortunately all the characteristics of quantum systems vanish with incredible speed if you put more than a few particles together. Entanglement and nonlocality (involving particles being connected with each other and able to influence each other at a distance) occur only under exceptional circumstances: at a temperature of one billionth of a degree above absolute zero and in extremely well-isolated surroundings. The quantum world is incompatible with a warm, complex system like the human brain or the world around it. That can be demonstrated in five minutes on the back of an envelope.”
Irresponsible Scaremongering
Van Lommel is of course free to put forward spiritual theories that aren’t supported by any research. There’s nothing new about his ideas. They have been around for thousands of years, held by many cultures, mystical movements, and religions. However, he should not fool people by giving his book the subtitle The Science of the Near-Death Experience. Nor should he, a doctor, frighten off potential organ donors with his completely unscientific theories. It’s baffling that he presents the nonsensical tales of organ recipients acquiring donor characteristics (see earlier in this chapter) as if they were truths. While claiming not to be against organ transplantation, he is wilfully scaring potential donors and their families unnecessarily.
Various hospitals are currently attempting to collect evidence of out-of-body experiences during an NDE. Researchers have placed playing cards on top of cabinets in the rooms of patients in order to test whether people see the cards when they are ostensibly floating above their bodies. As you might expect, patients who felt they were leaving their bodies haven’t been able to identify the cards. So all in all, there’s no reason whatsoever to regard NDEs as proof of observations outside the brain, or as evidence of life after death. Those patients never got as far as the hereafter.
In short, near-death isn’t the same as death, just as near-pregnant isn’t the same as pregnant.
EFFECTIVE PLACEBOS
The art of medicine consists in amusing the patient while nature cures the disease.
Voltaire (1694–1778)
The discovery that the most commonly used antidepressants aren’t significantly more clinically effective than a placebo was met with general amazement. It seems that physicians are strangely reluctant to sing the praises of the placebo effect, which occurs when patients show improvement after being given an essentially ineffective compound or treatment. As a rule, ineffective pills that are red, yellow, or orange are perceived to have a stimulating effect, while blue and green pills are deemed calming. Placebos can also have side effects, like nausea or stomachache. You can even get addicted to placebos, experiencing withdrawal symptoms when treatment stops. So the effectiveness and neurobiological mechanisms of placebos make a very interesting subject for investigation.
The placebo effect results from unconscious changes in brain function that reduce the symptoms of a disease. It is caused by the patient’s own expectations of treatment. While the substances in placebos are pharmacologically ineffective, their effect can be quite considerable. The placebo effect isn’t confined to pills; it also extends to psychotherapy, surgical interventions, and other therapies. For many years, psychiatric patients were advised to breathe into a paper bag if they felt a panic attack coming on, an approach that proved very successful. It was based on the theory that when you hyperventilate, you exhale too much carbon dioxide, ultimately causing a panic attack. But it later turned out that hyperventilation wasn’t the cause but the consequence of a panic attack and that breathing in extra carbon dioxide from a paper bag should theoretically induce a panic attack rather than relieve it. But because people believed in it, it worked.
Placebos can help to relieve the symptoms of Parkinson’s disease (caused by a lack of the chemical messenger dopamine) by making the brain release more dopamine. A similar effect can also be obtained by using electrodes implanted in the brain to inhibit the subthalamic nucleus. If a doctor tells a patient that he’s switching the electrode’s simulator on or off but doesn’t in fact do so, the patient’s symptoms nevertheless improve or worsen accordingly. During an operation to implant depth electrodes, an ineffective substance was injected into the intravenous line of Parkinson’s patients, who were told that it was a new anti-Parkinson’s drug. Electrical activity in that same brain area diminished as a result, reducing symptoms in over half of the cases. It seems that the brains of the patients responding to the placebo “know” in which area a change in activity is needed to alleviate symptoms.
Depressive patients who were treated with a placebo showed the same improvements after six weeks as patients who’d been given real antidepressants. Brain scans showed that changes in activity patterns were very similar in b
oth categories of patient. So the brain can be prompted by a placebo to bring about the exact functional changes that are needed to reduce the symptoms of depression: increased activity in the prefrontal cortex and reduced activity in the hypothalamus.
If a patient is in pain and is given a placebo, the brain “knows” how to suppress the pain by releasing more endorphins (morphine-like substances) and cannabis-like compounds and altering activity patterns in certain areas of the brain and spinal cord. An expensive placebo proves more effective than a cheap placebo. By contrast, because of their dementia, Alzheimer’s patients don’t expect painkillers to help. As a result, they don’t work as well, and such patients need to be given higher doses to achieve the same effect. The placebo effect is the result of the brain’s own unconscious self-healing potential. That mechanism can contribute little or nothing to the treatment of cancer but has been proven effective in a number of brain disorders. Studies of the mechanism of placebo effects and of why some people are more receptive to them than others (including whether a predisposition to spirituality plays a role) could have important clinical consequences. In the meantime we certainly mustn’t underestimate the effectiveness of the doctor figure, whose traditional power to inspire confidence makes him a walking placebo.
TRADITIONAL CHINESE MEDICINE: SOMETIMES MORE THAN A PLACEBO
Acupuncture outperforms placebos.
Since time immemorial, traditional Chinese medicine (TCM) has held that an incredible number of substances and foods are good for your health. In fact, the Chinese like to claim that everything that’s tasty is good for you and will prolong life. But there are also serious studies suggesting that the widely publicized benefits of unfermented green tea are well founded: It appears to reduce the risk of cardiovascular diseases and certain forms of cancer. Based on seventeen national screening trials, it’s estimated that you’re 10 percent less likely to have a heart attack if you drink three large cups of green tea a day. Green tea is thought not only to counteract high blood pressure and obesity but also to protect the brain. Various traditional Chinese herbal preparations are believed to diminish dementia symptoms, and modern techniques are being used to determine their active ingredients and functional mechanisms. Cat’s claw herb (Uncaria rhynchophylla) combats beta-amyloid plaques and so might be effective against Alzheimer’s. However, claims that green tea can combat Parkinson’s and Alzheimer’s still need further evidence. In TCM, millipedes, beetles, and worms are traditionally held to counteract dementia. Extracts from these creatures have indeed been shown to inhibit acetylcholine esterase activity, just as the Western medicine prescribed for Alzheimer’s does, which does help certain patients to a degree. It’s by no means impossible that Chinese research into traditional medicines will bring to light entirely new active substances.
Acupuncture, that exotic therapy with its impressive rituals, creates high expectations in patients and certainly has a placebo effect. The question is whether that entirely accounts for its effectiveness or whether the ancient Chinese notion of meridians and classic acupuncture points is meaningful. But studies show that determining the source of acupuncture’s effectiveness can be very complex. Here are a few examples.
One study, testing the efficacy of acupuncture for migraine, arbitrarily divided patients into three groups. The first group was given genuine acupuncture, in which the needles were inserted at the classic points and the doctors had to elicit “Qi,” a radiating sensation regarded as a sign of the needle’s effectiveness. The second group underwent fake acupuncture, in which the needles were inserted at predetermined non-acupuncture sites. The third group was placed on a waiting list. The treatment of the real acupuncture group didn’t prove more effective than that of the fake acupuncture group, but both groups benefited more than the group on the waiting list. From this one could conclude that acupuncture is effective but that the significance of classical acupuncture points, at least in the case of migraine treatment, is debatable. However, it’s impossible to say whether the benefits were achieved by a physiological mechanism or a very strong placebo effect. The same result was achieved in a similar study of three groups of patients with tension headaches.
However, in a similar experiment with patients suffering from osteoarthritis of the knee, acupuncture proved more effective. This study compared “real” acupuncture treatment with minimal acupuncture (in which needles were superficially inserted in non-acupuncture points) and a waiting list group. After eight weeks of treatment, the patients who had undergone real acupuncture showed significant improvements in terms of pain and knee function compared to the group receiving minimal treatment. Although the difference between the two groups diminished over time, a clinically relevant treatment effect was established. In the case of chronic mechanical neck pain, acupuncture proved statistically effective but clinically ineffective. In that study, electroacupuncture was compared with fake electroacupuncture (in which the treatment was identical but the needles weren’t hooked up to a power supply). In the absence of a control group, the effect of the acupuncture needle itself couldn’t be determined.
A brain imaging study looked at differences in brain response to acupuncture treatment, specifically at the expectations that patients suffering from painful osteoarthritis had of the treatment. In a single blind randomized crossover trial, three interventions were compared: real acupuncture, placebo acupuncture, and overt placebo acupuncture. The placebo group was treated using a Streitberger needle—a special kind of needle that, when pressed against the skin, moves back into the handle, giving the impression that it has pierced the skin. The overt placebo group knew that their treatment wasn’t therapeutic, having been told that the needle wouldn’t pierce the skin. None of the three treatments had the effect of reducing pain. However, scans showed that the ipsilateral insular region, which coordinates bodily autonomic reactions, was activated more by the real acupuncture needle than the Streitberger needle, although both treatments created the same expectations in patients. The two interventions caused greater activity in the prefrontal cortex, anterior cingulate cortex, and midbrain than the overt placebo treatment, of which patients had no therapeutic expectations. This experiment shows that acupuncture needles can have a specific physiological effect and that a patient’s expectations of treatment stimulate brain areas associated with reward. So acupuncture can do more than just achieve a placebo effect caused by a patient’s expectations of therapy. But in order to establish acupuncture as an evidence-based form of medicine, one would need to perform similar experiments for every disorder. Animal trials can play an important role here. Painkilling in rats by means of electroacupuncture was shown to be linked to higher concentrations of vasopressin in the paraventricular nucleus, while levels of oxytocin and opioid peptides remained the same. Vasopressin can be measured in the blood, which may prove useful in evaluating the effectiveness of acupuncture and its functional mechanisms in humans.
HERBAL THERAPY
Herbs can contain active substances but also very toxic ones.
Herbal medicine is an immensely popular form of alternative therapy. Around thirty thousand herbal products are offered for sale in the United States, and around $4 billion a year is spent on them. If you have a chronic illness and the doctors can’t really help you, there comes a moment when most of us feel the need to try alternative therapy. Everyone knows someone who knows someone who was suddenly cured by it. (Curiously, no one ever mentions that diseases sometimes go away by themselves.)
An important contributing factor to the perceived success of alternative therapy is probably that alternative doctors are much nicer and make much more time for their patients than regular doctors. Belief in the effectiveness of alternative therapy, both by the practitioner and the patient, is often the best form of placebo.