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INSIDE THE NEURON: CONSCIOUSNESS, UNCONSCIOUSNESS, SPLIT CONSCIOUSNESS

Their statues are made of silver and Gold

The product of the hands of man

Nostrils they have, but smell not;

They have hands, but feel not;

Feet they have, but walk not,

Neither do they utter a sound with their throats.

Those who make them, shall become like them,

Also those who confide in them.

-Psalm 115

Entrée: Consciousness: A Chorus of Choruses:

You can make the argument that brain science is the most powerful science of them all. The line of reasoning goes something like this: All experience funnels through our brain, the instrument of consciousness. Thought, emotion, behavior are expressed as physical events inside neural circuits. If one day we master our own biology we will know everything. When it comes down to it, all knowledge is registered in the physical brain.

Mind and brain comprise one machine conforming to the laws of chemistry and physics. Human action is the output of brain and body, the result of physical processes, of automatic cause and effect. The reason persons seem to act as free agents, is that scientists have yet to uncover all details of the working brain. If all experience results from electrophysical processes, then every mental event is determined by its antecedents. Thus the idea of free will is illusory and conflicts with biological knowledge.

For those not preoccupied with these issues, science has encroached on their self-concept very little. They are deluded into thinking they are acting of their own free will. But make no mistake. Scientific knowledge will engulf them. New discoveries and scientific techniques will one day alter their cherished beliefs. We do well to learn all we can about our physical selves, which is the ultimate source of self-knowledge.

Another view is that the brain merely brings experience to fruition. In that case, biology is slave to another process, an outside will, soul or essence. Electrical and chemical processes express mental events, but aren’t their initiators, or authors. One major support for this point of view, is that no one can tell us where the desire to perform even the simplest act, begins in the brain. The anatomist cannot say where in the brain the command even to move one little finger, starts. The philosophy separating the physical brain from some numinous agent controlling it, is the apostasy of dualism, refuted by scientific knowledge.

Scientific determinism on the one hand and dualism on the other, are insufficient models of human behavior. Both are too simplistic. The reason, I think, is that people have very long ago learned to leverage their mental abilities. We have formed complex social, linguistic, artistic, technological structures. That is the human enterprise. All of this is extra-cerebral, outside of our heads, certainly outside the purview of an individual’s head, and it is the key to our free will in the sense that these structures are no longer determined by biological events. You can make the argument that all of these endeavors began as some kind of biological or adaptive initiative, but they have attained a life of their own by this time and no longer have biological determinants. Indeed the reason for a good part of human endeavor is to somehow escape natural events. It’s why we create shelter, plant crops, fight disease, form groups, design machines, create art, study the world around us. Biology does give us basic information about our innards, but cannot tell us everything about ourselves.

Alzheimer’s disease is a case in point. In Alzheimer patients we witness a mysterious disintegration of cognitive function and then of the entire personality. Very simply, it now seems that beta-amyloid accumulates in the brain and causes the disease. Thus the dissolution of the personality reduces to the accumulation of a chemical in the brain. The slow destruction of cognitive capacity and personality is a process to be followed under the microscope. Alzheimer’s develops in Down's patients who have three copies of the twenty-first chromosome coding for extra amyloid and thus make amyloid in excess. In four types of familial Alzheimer disease that so far discovered the common feature is Beta Amyloid accumulation.[1] Amyloid accumulates in the senile plaque, a structure recognized under the microscope. The senile plaque is the major pathological element in Alzheimer disease, a probable first cause. It means little that in some studies the absolute quantity of senile plaque does not correlate as directly with dementia as much as some other microscopic features such as neurofibrillary tangles or that proteins, one designated “tau” may also be involved. This latter is an effect whereas Amyloid is the cause.

All at once we have a simple mechanism of causation of this mysterious disease. One day soon doctors will beat Alzheimer’s disease by blocking the accumulation of beta-amyloid in senile plaque. More to the point, here is an example of the gross disintegration of the personality explained by events on a microscopic and biochemical level[2].

Amyloid, and so-called paired helical filaments and other Alzheimer changes also accumulate in muscles of aged individuals. All of these changes are clearly visible in the muscle disease common after age 50 termed “inclusion body myositis[3]”. Here we find the very same pathological elements as are present in brain right in peripheral muscle!. Inflammation seems to be part of the problem, at least in many cases where the lymphocyte, a type of inflammatory white blood cell, infiltrates muscle. Changes in blood elements such as platelets reproducibly appear in Alzheimer disease suggesting that certain blood cells may be instrumental in transporting and depositing injurious substances in Alzheimer disease and inclusion body myositis, a form of senile muscle disease. Inclusion body myositis is partly ameliorated with anti-inflammatory medication and theoretically anti-inflammatory medicine may help prevent Alzheimer disease as well.

Figure 1: Senile plaque of Alzheimer disease. Microscopic abnormality explains mental changes of disease process.

Still, what is visible to family friends and physicians too in Alzheimer’s, is the disintegration of the person. Little by little former interests fall away as inclinations, motivation an inner fire extinguishes. This gives insight into normal function as well. It’s obvious that some persons have more intellectual fire and motivation and intense level of interest than others, a natural continuum of the level of interest in the world. Persons in the process of losing intellect often resemble those of lower capacity who never had it, so that you get an idea that intellect and the quality of experience may be determined by some mathematical representation of the total cognitive power of a brain. The decline in the cognitive power of the brain in Alzheimer disease relates to accumulation of a toxic substance and cell death. Persons possessing a certain gene, ApoE4, are much more likely to have Alzheimer's because beta-amyloid is more easily transported into their neurons. That is an adequate mechanism for the disease.

So Alzheimer’s is an example of how a relatively simple process, here accumulation of a toxic chemical, may have profound consequences. Fine you may say. A mystery has been solved. Having done so you open up a Pandora’s box of further issues.

Suppose modern medicine were able to prevent Alzheimer’s disease, as it seems likely to the case soon, by coming up with chemicals that simply block the accumulation or transport of amyloid? That would have profound social effects. As upwards of 50% of nursing home admissions are blamed on dementia, productive life would extend well into advanced years, so long as mental function could be preserved. The discovery of a treatment for Alzheimer’s would undoubtedly extend life. On the surface of it, this would be wonderful. Cognitive function could be preserved in one’s last years. But that would lead to other forms of social upheaval.

Industrialized countries already face a sharp increase in the proportion of elderly to young individuals who compete for economic resources. One wonders if over the long run medical advances that extend the lives of the very old are in fact a blessing. With age comes the accumulation of debility, but even more important, continued consumption of resources and wealth that could be used to improve lives of the young, the infusion of new life and ideas contributing to the well-being of a society as a whole. Always when we find a solution to a problem such as this, we create a host of other difficulties. Which is more adaptive – to extend the life and productivity of the very old or experience the springtime of renewal that can be attained only by the young? Successful treatment of Alzheimer’s and other diseases of the aged would alter our society in fundamental ways. Robust grandparents and great grandparents might be the primary caregivers of the very young, freeing persons in their middle years for other forms of productive labor. Even so lengthened life expectancy would place persons of all ages in competition for scarce resources.

Given that it is natural for the old to become less functional and die off, a planned obsolescence of sorts, one wonders if this in fact isn’t for the best. Life is finite so as to clear the way for the trial of the new and very young. This is the end result of natural selection, a trial of many possibilities. The old must make way for the new for a group to survive and adapt.

It will not be easy to find a sufficient biological explanation for another complex and poorly understood phenomenon, male homosexuality. A biological explanation for homosexuality would at one blow, negate almost all philosophical, religious and political rhetoric as those who maintain that male homosexuality is a lifestyle choice may be proven wrong. Male sexual preference is established very early in life and is likely to be biologically determined. In many primate species relatively few males have the pleasure of performing the majority of heterosexual copulations. This means that not all males contribute sperm to the gene pool, even when the ratio of males to females is close to 50:50. The presence of more males than is needed to procreate may add to the survival of a tribe, for example to increase cohesion or provide defense, so that homosexuality may be adaptive for a group whose members share many genes. Families with male homosexuals might even have some genetic advantage in that dominance hierarchies and division of labor among males may be firmly established or, alternatively, limiting numbers of offspring. New work implicates certain anatomical differences in the homosexual brain that may be heritable, especially in the hypothalamus, a tiny but powerful structure governing appetites sexual and endocrine function. These differences have not been replicated by others and are somewhat conjectural.

Consider the possibility that a homosexual tendency resides on the X chromosome. This putative gene could change the hypothalamus that controls basic emotions or work through another mechanism. If this work pans out, making homosexuality a model of biological causation, many other complex behaviors are sure to be explained as well. But it is just as reasonable to suppose that the entire answer is not in physiology or anatomy[4]. Identical twin studies among homosexuals find only an impressive concordance rate of between 50 and 67%, but still a non-genetic element is part of the story. Homosexuality must have a much more complex mechanism that the simple accumulation of a chemical substance in the brain as described for Alzheimer’s disease but if we succeed in describing the biology of homosexuality, this would have far-reaching consequences. I suspect that we may never be able to do that, that homosexuality is in part biological and part motivational. If so, or if this proves to be the case for other complex sets of behaviors, this would underscore the limits of biological causation.

Obesity is falling under the sway of brain research. Is it motivational or genetic? Pima Indians[5] who live in Arizona are obese compared with their close relatives in who reside in Mexico. That would argue against a genetic mechanism for obesity. There are also significant differences in identical twins reared apart, and a marked increase in obesity of immigrants who move into economically advantaged regions within just one or two generations. Thus obesity appears to be caused by the availability of food. Most Americans have food whenever we want it and obesity is on the rise. Persons, who have inherited efficient use of calories that has enabled survival under conditions of scarcity and starvation, suffer when things go well. They are the first to get fat and to gain weight. This implies that in conditions of scarcity of food, some obese persons who we consider to be unfit, might be the ones who survive, while those who are thin and fit in our own environment of relative abundance of food would be the ones to die off.

What then should be the approach to dealing with obesity in the economically advantaged parts of the world? In the USA obesity is a major public health problem. Policymakers have suggested that unhealthful behavior such as eating a lot of hamburgers and fats ought to be discouraged through a change in our tax structure or that insurance should be more expensive and the like. Fat people should be made to pay for their gluttonous habits. But do people truly choose to be fat? No one knows.

A combination of appetite-suppressing drugs, that simulate the action of Serotonin perhaps, or a host of newly discovered proteins that signal satiety within the brain, plus false nutrients, low calorie or non-absorbed fats and sugars, drugs that cause fat malabsorption are proposed remedies. Ironic that rich persons with access to all the food they could possibly want and more, are so bloated they need to starve themselves to escape obesity, or they need to do heavy exercise just to get rid of the excess calories they can’t stop themselves from consuming. Other folks who are less fortunate die from malnutrition and poverty. Gluttony vs. poverty. Does it seem as if we will one day find a biological or pharmacological solution to these problems? Here I have grave doubts. This too underscores the limitations of proposing a biological solution to what seems to be an non-biological problem.

The three examples above progress gradually from Alzheimer’s disease whose cause is likely to be biological, to male homosexuality which is likely to be multifactorial, to obesity which is most likely to be primarily behavioral except exceptional situations. It is clear that a biological model has sharp limitations in all of these instances.

Alcohol and drug addiction, aggression and other personality characteristics may have a biological cause. Scientists just don’t know the role of brain chemistry and physiology in these disorders. When we find changes in the brain of an addicted person are they cause or effect? An addictive tendency does tend to run in families and could be inherited. A drink of alcohol has less effect on person who is prone to become alcoholic while a single beverage provides a more dramatic quick buzz to someone who is less prone to drink, so one argument goes. A future alcoholic drinks more to attain the same effect. This is before he has habituated to the effects of the drug. Or with alcohol as with other drug-seekers, the addiction-prone may be seeking a thrill, due to a genetic character that increases activity in the thrill seeking chemical Dopamine in the brain. This mechanism would seem more applicable to stimulant type drugs, rather than sedatives such as alcohol. In any case, other sets of behaviors that seem now to be a matter of choice, will fall under the sway of biological causation. Biological research will demystify these behaviors as vague concepts such as choice and human will acquire mechanical explanations. Complex behaviors and personality characteristics that today stimulate moral arguments may be reduced to simple biological processes or turn into definable disorders treatable by medical intervention. The trend is for "psychiatric” diseases turn into "neurological" disorders as soon as problems are found within the brain, though significantly we have yet to see any very dramatic examples that have fundamentally changed our view of behavior.

Schizophrenia exemplifies this trend. Schizophrenia, or severe thought disorder with a poor prognosis, was at one time related to upbringing. Certain theorists championed concepts such as a so-called schizophrenogenic mother, who through her outrageous behavior caused her children to become schizophrenic. This theory quickly lost popularity as data about schizophrenia accumulated. The effectiveness of certain medications in schizophrenia, allowing patients with this chronic, and terrible disease to function outside the hospital, made a powerful argument for a physical cause. Certain anatomical abnormalities in the brains of schizophrenic patients relate tantalizingly to the disease. These include enlarged ventricles, indicating a loss of brain volume and anatomic changes within the temporal lobes of schizophrenics. Psychotic depression as well, is surely a neurological disease. Again the major argument at this point is pharmacological. Psychotic depression relates to disordered neural transmission, and the most efficient treatments are pharmacological. The effect of medications on these disorders has been considerable, allowing severely ill persons to function, yet the effects hasn’t exactly been staggering. Persons afflicted with psychosis very much still have their disorders even when functioning very well.

Even the approach to neuroses that traditionally have been felt to have non-physical causation, most particularly one of the most common, panic disorder, is also chemical. Insurance carriers have noticed that psychotherapy is ineffective and expensive. Holding the purse strings for medical treatments insurance payers strongly "encourage” drug treatment.

You can argue that panic disorder is caused by psychological mechanisms, even though it certainly responds to drug treatment over the short term. The brain is in the middle here, and short-term results can be gotten with drugs even though the basic cause is really an extreme fear brought about by thought processes having to do with unfulfilling life circumstances and pressures. Perhaps this process goes out of control and the fear response assumes a life of its own. Efficient short-term treatment is in the form of a quick acting sedative, more potent long-term solutions may be connected with brainstem transmitters such as Serotonin. But the basic process begins with certain ennui or life-threatening non-fulfillment that eventually needs to be addressed. One strong possibility is that the psychological process uses the brain as a substrate, a stage on which to act out its drama, and temporary treatment regimens may utilize brain chemistry even if the root cause lies elsewhere. At the very least, no one has been able to prove or disprove any of this and it is a mechanism worth remembering, because the same kind of faulty logic pervades understandings about the brain and psychological mechanisms, which affect it. Motivational processes, heretofore somewhat mysterious, are reduced to biological tendencies even disease states, removing all concepts of culpability and punishment, even considerations of motivation and free will. Consider the implication of discovering the biology of alcohol, drug addiction even kleptomania or even of finding the changes in the brains of murderers and violent criminals. When biological explanations for deviant and normal behavior too are deemed sufficient, philosophical, religious and political vision thoroughly changes. What we have then is a whole spectrum of behaviors and personality characteristics, some of which are more, some less, proven to have a biological mechanism. Yet there is the sense at least that all behavior can be reduced to a consideration of biology, mechanistic even automatic, not at all controlled by free will.

If matter and physiology is all, the real question is whether someone will one day be able to put together a mechanical device, most likely made of Silicon, that will recreate or even go beyond human experience. Brain scientists are on the verge of concluding that consciousness is no more than the mere interaction of modules or pieces brain real estate, anatomical sections of brain, now more precisely described than ever, that communicate well enough to give the illusion of experience. Even at our current level of knowledge, more data is accumulating indicating the failure of this model or at least showing that it requires fine-tuning. Consciousness produced by interacting modules yes, which include the reticular activating system, limbic structures, thalamus, frontal, parietal lobes, but these and other smaller and larger sections of brain function simultaneously and in parallel. Connections and interactions don't necessarily function in the rarefied realm of computer logic either. Some aspects of the connectivity may be illogical. These issues will be described in greater detail in the pages that follow.

The product of this interaction, we perceive as human experience, is more like a chorus composed of individual voices singing together or even a chorus of choruses. My model here is Gustav Mahler's huge 8th Symphony otherwise known as "The Symphony of a Thousand" a chorus of separate choruses (plus orchestra). A neuron is the individual voice coordinated in a group or smaller chorus, or nucleus of cells, Nuclei, sometimes silent and sometimes active, are the smaller choruses. The harmonious (or cacophonous) output, the chorus of choruses, is the symphony of consciousness. Note that the connection between these elements is not logic alone, but involves quite a bit more, emotional, musical and other relationships variously amalgamated into a cohesive conceptualization, just the kind of relationships it would be near impossible for the computer scientist to reproduce. Nervous system functional anatomy is also simultaneously hierarchical and interactive, even more a chorus of separate voices not a full linear logical progression in a top-down or interactive design. These are concepts that will be dealt with in the pages that follow.

Figure 2: A horizontal (cross-sectional) MRI image of the brain. A thin ribbon of gray encloses predominant white matter.

Looking at a gross picture of the human brain and one thing is striking. There is far more white than gray matter. The white mater is the wiring, the communication pathway between gray matter, neuron cell structures, and cortex and brain nuclei composed of cell bodies. You have to come to the conclusion that the brain must be more involved in communication between parts of the structure than initiation of messages. Messages ramify and resonate to a far greater extent than they are actually created. If experience is a chorus of different parts then it is logical to ask where is the chorus master or conductor? The simple answer is that we do not know. It is fascinating that we have come tantalizingly close to a physiological understanding of human experience but have yet to define the most important element anatomically, physiologically, a central organizing executive. Some may say that this is somewhere in the frontal lobe of the brain, the part that has most lately developed in evolution. But this is at best a vague concept. It is far more likely that what we actually perceive as a unitary experience is organized in much the same way as a choral piece or a symphony. We have a group of voices, tied together by some unitary conceptualization that comes from some outside agent, such as a composer of the work. The problem is that it’s not possible to find this organizing principle anywhere in brain anatomy.

The upshot of all of this is that we shan' t expect any computer scientist to reproduce in Silicon, human brain function any time soon. Material, physiological descriptions fall far short of reality.

Considered from the vantage point of abnormalities and deficiencies, from a disease model, you are almost forced into a mechanistic materialistic version of brain function. The brain, even the personality misfires like a car lacking some of its pieces. But the brain can function optimally, which means without disease with no lesion or disorder. The absence of disease the brain, like the rest of the body, will allow optimal normal function, just as the car with everything working will put out an optimal performance. In other words the absence of disease has nothing more than a permissive effect on behavior. Absent a certain amount of brain matter a person will not be able to learn well and he will have mental retardation or dementia. Lacking the chemical Serotonin in some areas of the brain, a person will be depressed, and so forth. A normal brain will permit someone to learn, and not to be depressed. At the same time you get the feeling that slow learning and depression will always have a physically definable cause. The question is whether these physical processes account for anything more than function in the absence of disease, whether we can extrapolate from consideration of deficits that impair function, into all aspects of normal or even better than normal human behavior. What is responsible for our going beyond our basic level of performance and is that physical or intangible? Will or will not biology eventually account for everything or will there always be some residuum that is beyond biology?

Death in the ICU or What Coma Teaches Us about Consciousness

"I don't think anyone unconscious is dead inside. They may be only more difficult to access."

-Oliver Sacks

The favorite method of neuroscience is the lesion experiment. To determine the function of a part of brain, you destroy it. Then you examine the subject animal for deficits. You conclude that the area of brain lesioned helps do the function that is lacking when it is gone. Cut out the right frontal lobe and an animal is paralyzed on its left side. The right frontal lobe must control movement on the animal's left. A simple deduction.

Brain death is the ultimate lesion. The lesion is all of the intracranial contents. So brain death gives us a chance to start with nothing. Nothing is assumed. It gives me an opportunity to start from the beginning and to build upon my arguments from scratch. The hospital Intensive Care Unit is the place where people encounter Brain Death. Because of nominal survival of the rest of the body enormous cost of continued care, it is a much harder issue to deal with than ordinary total body death. People tend to treat brain dead persons as living, even if, according to statutes in most states, they are legally dead. Even professionals have a terrible time talking to relatives of the brain dead patient because as the heart is still beating, and machines give breaths, the patient looks alive. Hence they tend to speak in equivocal terms often bewildering to the family.

The brain defines the individual. This is a given. Brain death is the very model of this teaching. When the brain is dead life is over. The quality of experience reduces to the function of the brain. An attempt to measure the quality of life reduces to assessment of cerebral function. This is what we assume, but is it true? Is it possible that brain only an apparatus of awareness, or is awareness nothing more than the sum of complex biological processes?

The Brain Is Not Different than Other Organs:

Having spent my professional life treating diseases of the nervous system, I’ve acquired a slightly different perspective on consciousness and the brain. As a medical doctor you learn to use the very same strategies to preserve cerebral function as you use for other organs. Daily experience shows the brain to be just like all the other organs in the body. It causes you to question the idea that the brain is initiator or author of experience rather a medium for experience. Just like other organs the brain depends on a specific molecular milieu for survival and optimal function, only perhaps more so; the brain is a little more particular than other organs are. Body temperature, serum sodium, potassium, oxygen, and acid-base balance must be right. This is just what the kidneys or the gut or the liver require. True, the brain is semi-isolated by a blood-brain barrier, but the brain is an organ, and behaves the same as other organs do.

Compared with the liver, kidney, I tend to put the brain on a pedestal, yet paradoxically, I have to come to the conclusion that all the great scientists who write about the brain and talk about it as the repository of consciousness and everything human, are over-glorifying the structure. I see myself as the proverbial soldier experienced enough point out that all political problems can’t be solved by war. My daily experience has humbled me. I see how little I can accomplish. The brain aids in the enterprise of consciousness but is not responsible for the consciousness in toto at least it seems to me given the explanations below. Most everyone I’ve read who writes about the brain wants to find the totality of human experience in biology. But it seems to me with our state of knowledge now and in the foreseeable future, that's an impossible aim. As much as the brain is involved with consciousness, it is largely peripheral to the process of consciousness, perhaps not as peripheral as the gut or kidney which by the way are also involved, but peripheral. I am aware this is a minority view and that it even sounds preposterous but it will be proved as we go along. At the very least we will see that by far the biggest bulk of the brain, and very probably by extension all of the brain, is peripheral to the process of consciousness, initiation of the totality of thought and feeling.

An example is a brain operation that is popular for Parkinson’s disease, the pallidotomy. The procedure is used with advanced Parkinsonians whose level of function fluctuates greatly. These poor folks, because of long periods spent with their disease, alternate between total immobility and being overdosed with their medicines, which causes them to writhe and twist about. This operation lesions out a tiny area of the Globus Pallidus, (literally gray ball because area containing primarily neuron cell bodies look gray) deep in the motor controlling area of the brain and is done with advanced physiologic monitoring with the patient awake. The movement areas of the brain that are destroyed by Parkinson's disease, connect extensively with the globus pallidus, but even so, why exactly these patients improve has not been worked out. What you see after the surgery is done can be considered in some cases, a miraculous improvement. This is an operation on the brain an one of the higher areas of the brain yielding striking improvement in gait and other functions especially on the side of the body opposite the surgery. Improvement is so dramatic it can transform a person from an invalid to an active person in one fell swoop.

How is this different than the replacement of a limb by an artificial device, a replacement that helps a person to walk anew, or a kidney or heart transplant that transforms a medical cripple into a functional human being? The answer is that this surgery on the brain is not different. The brain acts as an organ like any other whose normal function enables a person to have a normal and fulfilling existence. As such the brain acts as a tool or enabler of normal function. In the future, we may be able to enhance cerebral capacities beyond the norm. This will bring about a truly revolutionary enhancement of human capacities and a redefinition of ourselves. We would not be the same, after all but have enhanced capacity. But that is some time in the future. We will then have broken at that instant the biological ties that limit us and our potential may one day truly be limitless.

Behavioral Output Isn’t Everything:

We have the two groups of phenomena, the output of the brain i.e. human experience and behavior, and the biological brain itself. We do not know how they relate precisely. We may agree with the consensus that all thought can be reduced to an understanding of biophysical processes. One problem is that we rarely examine anything except the physical representation of consciousness, behavior. Some of this is observed with instruments such as the electroencephalogram that looks at electrical brain wave activity, but is behavior nonetheless. A lot of people have tried to simplify the debate by maintaining that manifest behavior is all there is because behavior, the output of the brain, is all that can be examined and compared objectively. In looking at the brain, behavior is a convenient starting point as the output of the organism but there are so many more phenomena that can’t be ignored by wishing them away or agreeing that you are going to ignore them. Those who look at behavior alone, such as psychologists, rarely take into account the anatomy and pathology of the brain. They may ignore internal mental states simply because they cannot be observed by anyone but the person experiencing them i.e. these states are felt to be “subjective” and therefore not applicable to scientific objective scrutiny. But because internal states are not observable doesn't mean they aren't there or can be ignored. What we can most obviously see simply doesn't tell the whole story. It is only the part of human experience that is directly observable.

Brain death is our strongest argument that all behavior is caused by biological events because you can’t show that there is any residue of the personality or behavior after the brain is dead. Thus the lack of any demonstrable behavioral output in a brain dead individual argues forcefully that the sum total of the personality is expressed in the brain. The other side of this is the distinct possibility that brain death means only the destruction of the instrument of expression not the end of that consciousness.

There is another interpretation. There could be some other agent controlling brain function in which case the brain is merely used as a physical tool of expression of this outside executive. What I'm talking about is some other entity akin to the soul or human will, an executive hovering over and controlling brain function. After the brain is gone, there is no way to show that any such entity exists, not only that such an executive, it is frequently argued, does not exist, because there is nothing, no phenomenon, that it would help to explain. We have no need to invoke, an extra-cerebral executive to explain any currently observed phenomena so why talk about it? Francis Crick, co-discoverer or the structure of DNA, says as much in his book THE ASTONISHING HYPOTHESIS: The Scientific Search for the Soul. His "astonishing hypothesis" seems to be, that the soul does not exist.. The hypothesis is not so astonishing in that it seems certainly consonant with mainstream science today. Certainly scientific principles will eventually explain everything. Mental activity, emotions are epiphenomena of neural and physical events. By the end of the book Crick seems almost to trivialize philosophical concerns over free will, in localizing it to a little talked about structure in the brain, the anterior cingulate sulcusY .

There is no denying that once you have killed the brain, you observe no further behavior at all. But on the other hand, the same cannot be said about subtotal but very extensive brain lesions where the outcome varies. Given a giant stroke that obliterates one half of the brain, a lot of people never come back as an intact entity. They never regain their personality or responsiveness. But once in a while you may witness a surprising preservation of a personality. The affected person may have had a very strong personality structure before his injury. Then despite a seemingly devastating large brain lesion, his basic personality will be preserved. A medical colleague of mine had a huge right hemisphere embolic stroke. You could see on his head scans that fully half of his brain was gone and there was, at first, tremendous brain edema or swelling that affected the other side of the brain as well. It took him a long time to come around, months before he was any good for anything, yet his struggle was heroic and today he is a very impaired but he is very much the same person. Examining him, you will find certain "deficits", basic difficulties in much the same way that you would if he had lost an arm or a leg. Vladamir Lenin suffered a whole series of strokes near the end of his life, yet there are adequate records to show that he continued to function in much the same way almost until the very end, continued with his former perceptions and assessments. Indeed near the end in his final testaments he issued perceptive pronouncements about Stalin proving that he was more clairvoyant than his contemporaries. Boris Yeltzin's extra-cerebral problem after his after his series of heart attacks and alcohol addiction is qualitatively not different than Lenin's. The loss of a part of the brain brings us closer to basic cognitive function but it is very difficult to change what is basic about a person.

We are still left with the proposition that whenever we see a fellow human being, we are evaluating him on the basis of his behavior only, what is manifest, what we can see. Various neurological conditions produce degrees of inadequacy of behavioral output. A stroke may stop a person from moving his right side or from speaking even though he wants to move and may have a lot to say.

The difference between manifest behavior and internal processing can be seen in a condition known as locked-in syndrome. This terrible naturally occurring condition leaves a patient virtually unable to move at all even though his level of awareness is there. The subject is awake and aware and thinking but is unable to move, in a state of perfect impotence, completely dependent and unable to change his environment. Though he has basic bodily functions, his heart beats and he breathes. On the surface the pitiable patient with locked-in syndrome seems to be in coma, since he does not respond to his environment. Only in the past few decades was the true nature of the condition, a form of “pseudo-coma”, appreciated, for the subject is awake and aware, only he is unable to move. Such persons were thought to be in a coma until someone noticed a level of awareness in their eyes which can be made to move and even to express thoughts via an agreed upon code with vertical up and down eye movements. Gazing into an affected person's eyes gives the first clue that a level of awareness is maintained.

The commonest lesion causing a person to be locked-in is a stroke in the pons, part of the brainstem where in a small area all of the motor output fibers course. The reason why vertical eye movements are spared is that these emerge from a slightly higher area of the brainstem, the midbrain, which is unaffected. Level of function and sophistication, sapience is still judged on the basis of behavioral output in the end. Only here, our breadth of observation is restricted to eye movements which is the only preserved voluntary motor output. Certain patients with other neuromuscular conditions causing near complete paralysis are also locked-in. Since the voluntary motor system is the major behavioral output that one can observe, and the motor system is efferent, outgoing from the brain to the environment, we say that such an unfortunate person is de-efferented, disconnected from his environment so far as motor output is concerned.

Now this is an interesting condition of complete and utter helplessness, an inability to do almost anything, to influence anything in one's environment, particularly if one's condition goes unrecognized as it sometimes does and life is just simply preserved without anyone noticing that there is still an awake thinking person inside. This is a sort of eerie "brain-in-a-bottle" experiment. By this I mean that supposing for a moment that after you died one could store your brain, in an awake and aware state, away from your body, keep it alive, with you thinking and dreaming, in a sort of nutrient fluid, floating in a jar on a shelf. How would that be for a person? Possibly one of the world's most horrifying experiences. But there are motor feedback loops as well as sensory ones, a constant communication and interplay with motor outputs that keeps the brain active in much the same way that you stay awake better even when you are tired while you are actually engaged in some activity much more than if you're sitting around just reading or listening and so very likely the de-efferented subject is somewhat numbed, anesthetized, during his long experience being cut-off from his motor output. The experience may not be quite as horrible as it seems to be. I know of cases where persons have recovered from severe paralysis, in myasthenic crises or after Guillian-Barre syndrome, an inflammatory condition of nerves causing a paralysis that can last weeks or months. Such persons aren't comfortable but don't describe a horror as bad as I would imagine under the circumstances. Perhaps some of us, being somewhat more kinetic, would not do as well under the same circumstances.

Brain Isolation:

Along these lines it is possible to come up with another means of disconnection from one’s environment which is so far is not well documented. A person may be unable to hear, see, taste, or feel. All sensory input could conceivably be interrupted in which case all sensory data from the environment would be cut off so a relevant response would also be impossible. Such a subject would be cut off from sensing his environment. He would retain all simple reflexes such as a simple withdrawal, eye movements, breathing swallowing and voluntary motor activity as well except that such activity would be irrelevant to environmental context because no data would reach consciousness and no voluntary motor output could be connected contextually to environmental stimuli. He would superficially seem to be awake and aware, but being

that he receives and processes no sensory input, he would not be responding to his environment except via automatic reflexes. Therefore he would seem to be awake but unaware.

This is similar to persistent vegetative state due to severe brain injury. The subject seems to have normal sleep and awake stages and may be looking about the room, but not fixating visually and while all the basic reflexes are there, even some rudimentary motor output, there is no evidence whatever of any awareness, awake but not aware. The eminent neurologist, Fred Plum, MD, famous as co-author of the classic text on Coma, presented a collection of patients with persistent vegetative state with complex organized motor activity even irrelevant speech. The key was that motor output, however complex, was not related to environmental stimuli[6]. But it is at least theoretically possible that even though a subject fails to show any contextual motor response, still he is awake and retains a level of awareness that is not apparent behaviorally due to the fact that all sensation is cut off. Since we speak of sensation as being afferent or traveling toward the brain, we have the obverse of the de-efferented state here what can be termed a de-afferented or locked-out syndrome. The disconnection with the environment is on the sensory sideF. One way to think about the thalamus is that New Testament expression, “No one enters the kingdom of heaven but through me.” Sensory data, as a general rule doesn’t make it to the brain, except through the thalamus.

This very situation was brought to the fore when the brain of Karen Quinlan was examined. This young woman' s plight was widely publicized one of the first "right-to-die" cases and she had been in a persistent vegetative state for many years before she finally died. Her parents petitioned for the right to withdraw medical care in her case. An examination of her brain disclosed that the brunt of brain damage was in the thalamus, the major sensory way station of the brain, through which pass tactile, visual, auditory, gustatory inputs. Such information at least raises the conjecture that a persistent vegetative state may result from ablation of sensory inputs to the brain without destroying large areas of cortex, which leaves a person both awake and aware yet behaviorally vegetative. That being said, the operational definition for a persistent vegetative state in medical parlance is that the person is allowed to be awake but is unaware, that is there is no contextual content to consciousness. This occurs in most instances with widespread destruction and dysfunction of most of the entire cerebral cortex leaving a good part of the brainstem, the lower areas of the brain, intact. The basic problem is that we are forced to make these judgments on the basis of behavioral output. The philosophical conundrum is that by these simple discreet lesions taken together, pontine destruction causing the locked-in syndrome, plus thalamic destruction causing a locked-out syndrome, that a person may attain a state of perfect untrammeled awareness, being awake, and conscious yet be completely disconnected from the environment. Further, an outside observer would be likewise unaware of the pure thought processes still occurring in that person's brain because he would be unable to get at them to make behavioral measurements. Tantamount to a soul floating bodiless in another world unable totally to communicate with our own, but while theoretically possible, this is entirely conjectural at this point[7]!! In Eastern religious circles, this perfect isolation of thought might be considered a state of nirvana. To most of us conventional types, it is more like hell.

Figure 3: An MRI brain slice. The thalamus is centrally located here, bordering the fluid-filled third ventricle. Eyes are on top, occipital lobe or back of the brain at the bottom.

I’m not saying that having pure isolated functioning cerebral cortex ever exists, even in an intensive care unit. Such a situation where a discreet lesion is made in the thalamus and also the pons would never and likely has never occurred naturally. De-afferentation in particular, is bound to have many other effects on consciousness so that a total isolation of a thinking brain from its environment is probably impossible. For one thing, the thalamus also helps to keep the cortex in a waking state. I only describe it here to illustrate the existence within the brain of afferent, incoming sensory vs. efferent, out-going, motor limbs or divisions of function.

Figure 4: Isolating lesions of the brain. The brain is partitioned from the outside world through the bottlenecks of thalamus and pons. Even with Afferent or Efferent limbs amputated it may think and emote.

One possible way to look at de-afferented state specifically would be through the sense of smell. If we had a patient with the specific thalamic destructive lesion, we could test the hypothesis of Deafferentation. Our putative thalamic lesion would not deafferent our subject entirely because olfaction (sense of smell) does not course through the thalamus, but goes instead directly to the frontal lobe. If a person in a persistent vegetative state is conscious but disconnected from all other sensory modalities, then it might be possible to communicate with that person using the sense of smell. This would have to be in a case that must be exceedingly rare, if it exists at all, of discreet thalamic damage causing a vegetative state.

Deafferentation undoubtedly has other clinical correlates. It is akin to sensory deprivation, only the complete anatomically pure case of sensory deprivation that is bound to have extreme consequences for awareness. In prisoners and other subjects who are sensory deprived, there are profound psychological changes. Lacking stimuli, many subjects will start to hallucinate. This may be due to the physiological mechanism of denervation hypersensitivity, described later. Neurons lacking input are hungry for it and tend to over-respond. Hence a person subjected to sensory deprivation may begin to come up with his own stimuli or hallucinate sometimes extremely.

Afferent, Efferent, Associative Limbs:

From the foregoing and on the basis of all current data, about brain function, we conclude that neural function has three components or “limbs”. These are Afferent, Efferent, and Associative. Afferent refers to the sensory side or processing of incoming information. Efferent, the motor or doing side, by which the nervous system manipulates one’s own body and the outside world. Associative or relating parts of the brain, refers to the sum total of internal processing of thoughts and feelings. This is what I refer to as the NeuroWeltanschuung or neurologist’s world view. For the neurologist the nervous system is the center of the world and he breaks nervous system function into afferent, efferent, and associative limbs

.

Figure 5: The neuro worldview with afferent, efferent and associative components.

A closer look at this simple construct will at the same time help explain and clarify while showing how useful these ideas are. We’ve all noticed that certain personality types have one or the other of these limbs de-emphasized or atrophied and others hypertrophied. A facile example is the artist who, stereotypically at least, is hypersensitive. The artist has a hypertrophied or overdeveloped afferent limb. Artists are supposed to feel, to receive, more profoundly than the rest of us, so much so that they are often non-productive. They lack at times, motivation and output, and are easily blocked. What does the artist do when he needs to put out his product? He retreats to his loft, to his workshop, or better, to the mountains, where he can finally cut himself off from overwhelming sensory stimuli and begin to produce, to finally paint, or to write or compose. He thereby cuts off his troubling afferent limb and finally begins to put out his oeuvre. Of course all of us know that many of the most successful artists are primarily doers rather than feelers and that most of them have a prodigious output under even adverse circumstances.

Contrary to this stereotype are both the athlete and the entrepreneur. They don’t think or feel much, not to let too many thoughts or feelings get in the way, but are always producing. They have an hypertrophied efferent limb. Then it is easy to appreciate the armchair philosophers, or mathematicians. Divorced from connections with the outside world, these folks are paid to think and associate. All of these situations are illustrated in the figures below.

Figure 6: Neuro-stereotypes on basis of occupation.

The brain lesion model provides a very useful platform for describing the necessary components for creating a conscious output. The parts of the brain necessary for conscious response have been well described using this methodology. The brain scientist breaks consciousness into two operational components, the maintenance of arousal and content of consciousness. To be conscious a person needs to be awake. Later we’ll get into the argument about whether sleep and other states are really altered states of awareness, but for the time being it simplifies things to require our conscious subject to be awake and aware.

The part of the brain that maintains arousal is a collection of anatomical structures in the brainstem designated the reticular activating system. These brainstem structures are under the cerebral cortex or you may say behind the cortex, closer to the tail of the animal. There are groups of cells that maintain arousal by virtue of connection to the cortex that essentially excites it, I like to say revs the cerebral cortex, keeps the engine of consciousness humming. When a large portion of the central brainstem is affected by such processes as trauma, tumor, infection stroke or any destructive process, a person will be unable to maintain wakefulness. On the other hand as we have seen, if the cortex is affected, a person may be awake but unaware. He may lack any substance or content to consciousness, even though seeming, superficially, to be awake. Thus the brainstem ascending reticular activating system or ARAS keeps the person awake and a good deal of its input is by way of the thalamus that connects extensively with cortex. The ARAS is ascending because the influences are going up or toward the highest areas of the brain. The thalamus is the rostral or most forward part of the ARAS.

Conditions Correlate with Specific Brain Lesions:

The table below is not fully understandable at this point. It is meant to apply the modular or component or mechanistic point of view of consciousness I have been discussing above. In the hospital ICU we see various conditions that affect behavioral output. With modern understandings we are able to relate these various conditions to specific lesions inside the brain with a fairly high degree of precision.

CONDITION	AWAKE	AWARE	LESION	EEG	EVR	REFLEXES
PVS	S/W CYCLES	NO	BILAT. CORTEX, OR THALAMUS	LOW & SLOW OR UNREACT. ALPHA	SER IS OUT BAER OK	YES
LOCKED IN	AWAKE (& altered sleep)	YES	PONS OR nerve or muscle	Near NORMAL	BAER ABN SER NL	YES
COMA	CAN’T BE AROUSED	NO	BRAINSTEM OR BILAT CORTEX	LOW & SLOW OR UNREACT. ALPHA	VARIABLE	YES
DEGEN DIS	YES (S/W Cycles)	REDUCED	VARIABLE (severe and diffuse)	NL TO SLOW	VARIES ACC’G TO CAUSE	YES
BRAIN DEATH	NO	NO	ENTIRE BRAIN	FLAT	ABSENT	SPINAL ONLY
AKINETIC MUTISM	YES	probable	MIDBRAIN OR FRONTO-MEDIAL (cingulate)	VIRTUALLY NORMAL	NORMAL	YES

Table 1 : DISTINCTIONS IN CLINICAL SYNDROMES PRESENTING WITH ALTERED CONSCIOUSNESS.(PVS= the persistent vegetative state.)

NOTES: 1. “CONSCIOUSNESS” = WAKEFULLNESS AND AWARENESS

2. PERSISTENT VEGETATIVE STATE (PVS): Complete unawareness of the self and the environment accompanied by sleep-wake cycles with either partial or complete preservation of hypothalamic and brainstem autonomic functions. In add’n: No sustained, reproducible, purposeful, or voluntary behavioral response to sensory or noxious stimuli. No language comprehension or expression. Bowel and Bladder incontinence. Full chew and swallow not present.

You Need to Be Conscious to have Pleasure or Pain:

A lot of times I'm asked if a comatose patient is suffering. How much does he know? Does he experience any pain? My stock answer is that you have to be awake and aware in order to truly experience pain and suffering. This is exactly the same argument that was used by surgeons forgoing anesthesia in newborns and prematures. The brain isn't well developed or myelinated with all connections intact. The baby i