Steps Towards Solving the Mystery of Consciousness
Without doubt the brain plays a pivotal and essential role in consciousness. We know this because if there is damage to a certain part of the brain following for example a stroke or a head injury, very specific mental functions may be lost, such as memory, or the ability to recognize others, or the ability to form sentences. We know this doesn't happen with any other organ in the body and so we can definitely conclude that it is the brain that is involved.
This has been confirmed in recent years with the advent of brain-scanning techniques such as functional MRI and PET that have helped to map out the areas of the brain that are involved in these functions. We have found a direct correlation between the mind, consciousness and the brain, but it is only a correlation and not proof of how the mind comes to exist. As with any correlation, we have to ask the question: does A lead to B, or does B lead to A? We know that there is brain cell activity in relation to the mind, but which way is the relationship? Is it the brain cells that activate the mind, or is it the mind that activates the brain cells, or could it even be both? Which comes first, the chicken or the egg, the brain or the mind? If we want to be purely scientific, we must keep an open mind and not let our own personal biases cloud our judgement. We should let the evidence guide us.
The majority of scientists currently support the view that brain processes somehow lead to the formation of consciousness. As outlined earlier, many different intermediary brain centres and pathways have been proposed to account for this. There are, however, other scientists, including the Nobel Prize winning neuroscientist Professor Eccles, who have supported the theory that the mind is a separate entity that cannot be reduced down to brain cell processes. Some have argued that we will never be able to account for the formation of consciousness through the electrical and chemical processes of the brain. So which of the scientific views is correct?
Until fairly recently there was little scientific evidence to doubt that brain processes lead to the formation of consciousness and the mind, even though there has been little evidence to demonstrate how this could arise scientifically. However, the study of near death experiences during cardiac arrest together with a lack of plausible biological mechanisms to account for the causation of consciousness from brain processes has led to major questions about this theory. Many may now have to reconsider their opinions based upon the latest data. After all, this wouldn't be first time in science that a prevailing view has been proved wrong. When we look back, we can see that many widely accepted theories have been modified or even completely changed in the light of new evidence. The formation of consciousness is far from clear and it could be that the latter view may be correct.
So how do the reports of near death experiences during cardiac arrest help the research into consciousness?
Numerous studies have shown that thought processes are mediated by multiple areas of the brain and not just a single area. For this, brain cells need to communicate, using electrical pulses. During cardiac arrest there is a severe insult to the brain that causes either no blood flow to the brain or at best severely reduced blood flow. Either way, there is such a deficiency in blood flow that electrical activity in the brain ceases within a few seconds and there remains a flatline throughout the period of the cardiac arrest and even afterwards for some people. Nevertheless, consciousness appears to be present in 10-20 per cent of those who are in cardiac arrest.
In normal medical practice, it is well recognized that any alteration in the function of the brain leads to a clouded sense of consciousness, which is highlighted by a confusional state, and if the impairment is more significant, consciousness is lost. All we have to do is spend an evening in an emergency department and we will see that people who have any significant alteration in the level of nutrients and or chemicals around the brain become confused. This can take place with any illness, whether pneumonia, a heart attack, diabetes or an infection around the brain. This is the basis of all mental tests on patients who have become acutely unwell. If such conditions are left untreated, they can lead to a coma. However, in all these conditions, the insult is still not so great as to cause the brainwaves to go flat. At worst they start to show changes in shape. How is it then that we have a clinical scenario in which there is severe brain dysfunction, the worst possible type, with an absence of electrical activity in the brain, but somehow thought processes, with reasoning, memory formation and consciousness continue and are even heightened?
It might be suggested that the thoughts are arising from a small area of the brain that is somehow able to receive blood flow, however numerous studies have demonstrated that thought processes are generated by global brain function, also it is almost impossible for one area to receive blood when there is hardly any blood flow to the brain. Scientifically speaking, there should be no consciousness present at all. How then can we account for the findings of NDE research? As Dr Van Lommel, a cardiologist stated, 'How could a clear consciousness outside one's body be experienced at the moment that the brain no longer functions during a period of clinical death with flat EEG (brain monitor)?'
The most obvious explanation seems to be that perhaps the experience isn't occurring during the period of cardiac arrest after all. Dr Susan Blackmore and Professor Christopher French, two British psychologists, have suggested that it may be occurring just before the crisis, or even just after, when the individual is still in an unconscious state but blood flow is relatively normal and brainwaves are present. Obviously, as the heart stops, there will be a period of a few seconds before blood flow is stopped to the brain, and after the heart recovers, there will be a period in which there is relatively normal blood flow to the brain before the person actually awakens. As memories and thoughts can take place in an instant, Blackmore and French have proposed that NDEs may also be occurring just before or after the event, but the individuals concerned think they happened during the main part of the cardiac arrest itself. This is possible, however there have been many individuals who have recalled details from the middle of the cardiac arrest, when brain blood flow has been shown to be severely impaired. There are also many physicians who have revived people during cardiac arrest who have then recalled in details what had happened to them. In cases such as these, we can't say that the experience was happening at the beginning or end of the cardiac arrest, as the patients recalled details of what was happening during the cardiac arrest. This is therefore an area that needs to be investigated in more detail. We need to be able to time the experiences accurately. Both Dr Blackmore and Professor French agree that if clear consciousness were possible with a completely flat EEG this would indeed change our view of the mind-brain relationship, but so far this has not been conclusively demonstrated.
From a scientific point of view, studying the human mind at the physiological point of death, when global blood flow, and hence brain function, has become severely impaired, is currently the best and possibly the only method to study the relationship between the mind and the brain. Should consciousness truly be present during this time, then this raises a very interesting point. If mind and consciousness are products of brain activity, then they would be expected to also cease functioning at this time, or at best very shortly afterwards. It is a little like going into a room in which there is a light and not knowing where the light is coming from. If we turn the switch off at the wall and the light goes off, then we can conclude that the light was coming from the bulb we had turned off. If on the other hand we switch it off and the light is still present, then we have to conclude that it must have been coming from another source.
So far we do not have definitive proof for either theory. However, as many thousands of people, including small children, have reported a fully functioning mind and consciousness and have been able to watch specific details that were happening during their cardiac arrest, the possibility is raised that mind and consciousness can exist separately from the brain and also during and at least for some time after death. There are also many anecdotal reports from medical professionals who have resuscitated patients who have upon recovery told them the details of what happened during their cardiac arrest.
The problem is that so far there have been no studies with adequate numbers of patients to investigate this phenomenon fully. When we look for a significant effect with a new drug, we sometimes have to study thousands of subjects, and the same is true with consciousness at the end of life. It is up to us as scientists to investigate these claims adequately and with appropriate studies, which are now possible. It is also for funding bodies to support such novel research, which could have profound implications for us all. If we take up this challenge then we can potentially answer the last completely unsolved mystery in biological sciences.
What then of the various brain-based theories to account for NDEs and consciousness? There is no doubt that the body affects the mind and consciousness and also that the mind and consciousness affect the brain and body. The most important point, is that identifying the brain-based chemical changes that accompany any subjective feeling or activity of consciousness will not be likely to tell us if an experience is real or not. It will simply give us the intermediaries that are needed to manifest a subjective event or feeling. This of course also applies to the study of the neural correlates of near death experiences. Finding the intermediary pathways and chemicals will not be able to tell us if an experience is real or not.
In light of the evidence from cardiac arrest survivors and the large amount of anecdotal evidence that has accumulated, we now need to test the nature of consciousness during cardiac arrest, when brain function is at best severely impaired or at worst ceased. This is now medically possible and will at least tell us which of the broad views regarding the relationship between the mind, consciousness and brain is correct.