The Future of the Brain, The Brain of The Future

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The Future of the Brain, The Brain of The Future Realising the Greek Mind in the Modern World

Can concepts of the human mind from ancient Greece actually have any interpretation in modern neuroscience? If we explore ideas of mind from each of the three major tragedians, then we might be able to see parallels between concepts developed in Greece of the fifth century BC and how they can be interpreted in current neuroscientific terms. Aeschylus arguably emphasised the chorus at the expense of any specific individual: in turn, therefore, the chorus could be seen as a deterministic force where the individual is just a hapless victim of destiny and determinism. In neuroscientific terms, determinism could be viewed as genetic. Let’s start then by looking at genes and how they work within the brain.

The best way to approach the question of how genes relate to complex mental traits would be to take an extreme counterexample, one where very unusually a brain dysfunction relates to one single rogue gene. Normally, brain disorders such as schizophrenia, Alzheimer’s, or depression are very complex in their relationship, ultimately with a provenance of many different types of genes. However, in the one case that formed the basis of a very insightful study some ten years ago, this wasn’t so: in this particular study the experimenters worked on a gene for Huntington’s Disease (Chorea) (van Dellen et al. 2000). Huntington’s Chorea, as its name suggests, comes from the Greek for “dance”: accordingly it is a disease where the patient presents with wild involuntary flinging of the limbs in a grotesque form of dancing. Unlike most other brain dysfunctions, this disorder relates just to one gene: so in this case the experimenters were able to manipulate the genes of mice so that they had the mouse equivalent of Huntington’s Chorea. It was very easy to evaluate the status of the mice’s movement by giving a score on various motor tasks.

The mice were accordingly divided into three groups: those that did not have genetic modification, and 2 groups where the gene was deliberately manipulated so that the mice as they aged were destined to have impairments in movement similar to that in humans. However, the 2 groups differed in environment. One group was kept in standard housing, the other in an “enriched environment.” Since rodents are highly exploratory creatures, “enrichment” for rats and mice involves supplying them with wheels, tubes, food hoppers, and other interactive objects that they can explore (see Figure 1).

Over the course of time, some 160 days, an interesting result emerged (see Figure 2). Figure 2. Nurture can Trump Nature. The animals that did not have the modified gene for Huntington’s predictably moved just fine throughout their lives. Those with the modified gene, however, in the standard housing lived out their genetic destiny and deteriorated in terms of their movement as they aged. In contrast, those with the enriched housing showed a marked difference, in that the age of onset was much later and the degree of impairment far more modest. So we can see that there is no one-to-one relationship between a single gene and a complex mental trait, even in the case of the simpler brains of mice and the extreme example of a single-gene disorder.

Let’s now turn to Sophocles, where more emphasis was placed on individuals, albeit as the hapless victims of their fate. Even though they were individuals, it was arguable as to whether they would actually have free will. How might we explain, then, the neuroscience of free will? In the middle of the twentieth century one idea, proposed by Paul MacLean (MacLean 1990), was of a “Triune Brain.” Because of the times in which he lived, MacLean was puzzled by behaviour, the seemingly mindless behaviour, of those at the Nuremberg rallies. His explanation was that anatomically the brain could be regarded in three evolutionary stages: the reptilian brain, comprising the inner core basic part; layered on to that would be the mammalian brain, comprising areas such as the limbic system and hippocampus; finally encompassing that would be the cortex, the outer layer of the brain, which is the monopoly of the neomammalian species. MacLean argued that these three layers represented increasing degrees of sophistication: the reptilian brain underpinned very primitive urges; these being channelled into context by virtue of having a mammalian brain; and the neomammalian brain imposing further refinements and morality, or rules on how one might behave.

MacLean’s idea was that the behaviours of those at the Nuremberg rallies represented an unleashing of the reptilian brain by a suppression of the more sophisticated outer layers. However, the problem with this idea is that the behaviour of those who may seem otherwise to have “lost their minds” is not comparable to that seen in crimes of passion—or, literally, mindless rage—but rather emotion channelled into a narrative, a story. For example, those at football rallies today, like their more sinister counterparts in Nazi Germany in the last century, are very mindful about who the enemy is and who they themselves are. They are living out not unbridled emotion, but a story. Interestingly enough, this story is frequently a David-and- Goliath narrative, with those who are exhibiting the collective rage being the David character, the small much-wronged helpless and weaker party, as opposed to the all-pervasive enemy, be it an international conspiracy or a large and powerful country like America.

This early version of how the brain works therefore doesn’t really help, with what we know of neuroscience now, in explaining how free will might come about. Instead we have to turn to the question of how the human brain actually does become a mind. The wonderful thing about being born a human being is that you are born with pretty much all the brain cells you will ever have. However, it is the growth of connections between the brain cells that accounts for the growth of the brain after birth (Figure 3). Figure 3. What is the Biological Basis of the Mind? The exciting aspect of this postnatal growth is that even if you are a clone, that is to say an identical twin, you will have a unique configuration of connections, because they in turn are driven, strengthened, and shaped by your experiences in the outside world.

One good example of this is piano playing. In one study (Pascual-Leone 1995), carried out over five days, three groups of adult human volunteers, none of whom could play the piano, were divided into respective activities. The controls merely stared at the piano, whilst the second group were taught five-finger piano exercises. Astonishingly, even over five days, you could see a remarkable difference in the scans of the brains of those who had learnt to play the piano. But more remarkable still were those who were merely tasked with imagining they were playing the piano: in their case the brain scans showed almost identical patterns to those of the subjects who physically did the playing (Figure 4). Figure 4.Area of Brain Controlling an Individual Finger (A. Pascual-Leone, et.al. JNeurophysiology 74 (1995): 1037-1045) This stunning result tells us that it is not so much the contraction of muscles that was responsible for the change in the brain configuration, but rather the thought that preceded it, which was common to both non-control groups.

The experiment shows that even a thought can literally leave its mark on the brain. This effect is dubbed by neuroscientists “plasticity,” not meaning of course that the brain is plastic, but rather from the Greek plastikos ‘to be moulded’. We even know now the basis for these dramatic changes in response to the environment, again from work on rodents. When animals, in this case rats, are exposed to an enriched environment, after a short while a difference can be seen in the brain cells. Those from the enriched environment have more branches emanating from the main part of the cell than those that do not. Why should the growth of these branches be important? The more branches a brain cell has, the greater its surface area, so the more it can act as a target to receive more inputs from other brain cells. So to recap: the more stimulating the environment, the more hard-working or “active” a brain cell will become, so the more branches it will grow, and therefore the more connections it can form. I would like to argue that this enables you to have more “significance,” meaning that you can see one thing in terms of something else.

As human babies, we are born into a “booming, buzzing confusion,” (James 1981 [1890] ) where we evaluate the world, in the words of the great psychologist William James, in purely sensory terms: how sweet, how fast, how cold, and how bright. But gradually those raw sensations, if they are repeated in correlating ways, will match up a certain visual pattern with a colour, a voice, a texture, a sound, a smell: it could all amount to your mother. In this way, like the piano players, if such experiences are continuously repeated, then the brain cell connections will accommodate that unique set of continuous coincidences. Accordingly we will shift from a sensory world to a more “cognitive” one, as in the Latin cogitare ‘to think’, where instead of putting a premium on mere strength of raw sensations, it is on those of specific significance to us, that is we are evaluating the world in terms of previous experience. We therefore progress from a one-way street, where we are the passive recipient of raw sensory data, to a two-way street where every experience can be seen in the light of what has happened before; meanwhile that experience will be modifying those ongoing connections.

Sadly, this beautiful personalisation of the brain can be dismantled, and we can retrace the steps of development with dementia: although Alzheimer’s Disease is not a natural consequence of aging, it is a disease of old people. What happens in this case is that the branches are pruned back so the connections can no longer form (Figure 5), and sadly, therefore, the patient gradually becomes like a small child again. Figure 5. They are unable to read off the world against the checks and balances of previous experience, and therefore they cannot interpret or make sense of what is happening. The world instead presents as the “booming, buzzing confusion.” No wonder such patients are disoriented and confused.

I would like to suggest, then, that each of us has a unique life narrative that leaves its mark on the brain, and it is this personalisation of the brain, driven by unique experiences, that we could regard as the human mind. We can understand more about what makes us so special, both as a species and as individuals, by comparing our brains to those of our nearest relatives: the chimpanzees. Interestingly enough, even chimps do not have our capacity for postnatal growth: the major part of the brain that seems to expand in humans compared to chimps is at the front, the so-called prefrontal cortex, which occupies 33% of the adult human brain but only 17% in chimps. Moreover, we can see that human individual development, or ontogeny, does indeed reflect phylogeny, in that the prefrontal cortex is only mature in the late teenage years and early twenties. The prefrontal cortex, then, seems an interesting part of the brain to examine if we are interested in sophisticated abilities such as the desire for freedom.

We started learning about the prefrontal cortex towards the end of the nineteenth century, when one Phineas Gage , the foreman of a railway gang operating in Vermont, had a disastrous accident in which a large rod was driven completely through his head, through the prefrontal cortex, when an explosive went off prematurely: this was the first case study of lesions of that area. Interestingly enough, his normal basic mental capacity was unimpaired, but the more rarefied cognitive functions seemed to be showing the greatest change: not only did he become reckless, but—again mirroring the idea that the prefrontal cortex is only developed later on, in the teenage years—the physician who examined him at the time, John Harlow, recorded that he had become “exceedingly capricious and childish,” “impatient of restraint,” and “a child in his intellectual capacity” (Harlow 1868). We can link then the prefrontal cortex with adulthood, and its underactivity with childhood.

Another group of people who have an underactive prefrontal cortex is schizophrenic patients. They too are like children, for example they cannot interpret proverbs in terms of metaphor. They might say, for instance, that the proverb “People who live in glass houses shouldn’t throw stones” literally means that if you throw a stone at your house and it’s made of glass, the house will break. Similarly, like children, schizophrenic patients are easily distracted, have short attention spans, and put a premium on raw sensation.

Another interesting group that also have underactive prefrontal cortexes are those who have a high body mass index, that is who are heavy compared to their height. Such people also exhibit recklessness on gambling tasks. What might be the common factor, then, among schizophrenics, compulsive gamblers, and compulsive eaters? Everyone who gambles or overeats knows the consequences of these activities, but they will still do so. I would argue that this is because, like the schizophrenics, in all these diverse cases the outside sensory world is trumping the consequences, that is to say the “cognitive.”

How, therefore, might this shift in the balance of power be happening in the brain? In order to understand what might be happening, we have to look at features of living in the here and now, the sensory world. Consider the state of being highly excited or aroused, feeling rewarded, and indeed being addicted to these behaviours. In all these cases a chemical system in the brain that underlies arousal or addiction to psychotropic drugs and reward generally is underpinned by a chemical called dopamine, a well-known chemical messenger (Figure 6). Figure 6. But dopamine also has more modulatory, nonspecific effects in a fountain-like way in the brain. We know that dopamine actually dampens down the prefrontal cortex, and indeed could underlie states of mind that we regard as highly emotional, rewarding, and sometimes addictive, for example when we talk of having a sensational time, letting ourselves go, and indeed “blowing the mind.” We can then think of the normal human condition as comprising two modes (Figure 7). Figure 7.

In the first, there is strong prefrontal cortex activation, where thinking dominates and there are normal levels of dopamine: in this scenario we are mindful of consequences; have a past, a present, and a future; and may have a conscious desire for freedom. In the other, in contrast, we can revert to the world of the small child, where one is completely in the here and now. We have strong feeling, are driven by our senses, and are highly aroused: in neuroscientific terms we have an underactive prefrontal cortex, inhibited due to an excessive amount of dopamine. Interestingly enough, this is when we might feel at our most free, although at the same time we may not have actively desired it in a self-conscious way.

The division of the human mind into these two states, which traditionally we have always contrasted in our lives, for example in Euripides’ Bacchae, forms the basis of my recent book ID: The Quest for Meaning in the 21st Century (Greenfield 2008). It seems increasingly that these two modes might not just underpin first our enjoyment of freedom versus our desire for it, but also that that we might generalise to the very challenging context that the new technologies are giving the generations to come.

And so we come then to the work of Euripides, who perhaps places most emphasis of all the Greek tragedians on individuals and their inner conflicts. If the environment and what happens to you is key in shaping your brain connections and hence your mind, then clearly we are faced with many different influences. I would like to suggest, too, that screen technology is actually imposing an environment rather akin to that of the revels in Euripides’ Bacchae, where a loss of mind is more at a premium than it would be in normal human nature.

First, the costs of attention deficit disorder: these have trebled in the last ten years. Secondly, screen culture is highly sensory, with intense stimulation of vision and hearing. There is a lack of metaphor and abstract concepts; what you see is what you get, and the emphasis is on mental processing and agility rather than on significance of content. So we come to a third point: when many play a computer game to rescue the princess, after all, little thought is given to the princess; whereas when we read a book the whole point of reading the book is that we follow the significance of events for that individual. Further, in a world where events are easily reversed, as in computer games, then that world will have no real meaning, that is continuity. Thus the people in it will have no significance and consequently we will not feel empathy for them: hence perhaps the reason for the rise in autism. Could this decrease in empathy for others actually extend to ourselves? If we ourselves are engaged in literally meaningless activities and do not have a past or a future, might we see ourselves more as passive recipients of sensory input rather than enduring entities? Certainly the affinity of those with autistic spectrum disorder, i.e. with reduced empathy, who are particularly comfortable in Second Life and other cyber activities would support this idea.

The final area that may be targeted is risk-taking. Risk-taking or excessive recklessness is a symptom of an under-functioning prefrontal cortex, which we have seen earlier is only developed in one’s late teens. Might it be that we are placing the young brain in new types of environments? It would be a world which mandates a shorter attention span, is strongly sensory, lacks abstract concepts, emphasises process over content, has little meaning, and encourages reduced empathy and identity and a reckless form of behaviour—where we are indeed revisiting the world of the Bacchae, a world of intense pleasure but no consequence. The issues are explored of how we balance the clear desire for wine, women, and song and for ‘letting yourself go’. Witness after all how the fate of Pentheus should indeed be balanced by a concerted effort to organise an environment for the next generation, where the full portfolio of human nature can be expressed.

In summary, the twenty-first century is imposing an unprecedented environment. Nonetheless, the new technologies pose the enormous challenge of freeing us up to live longer and healthier lives with more leisure time each decade. The big question that threatens to jeopardise this scenario is what the meaning of our lives actually is and how we see ourselves as individuals. These are questions explored by the three Greek tragedians, to whom we might return if we are to rediscover the balance so epitomised by μέν and δέ : thesis and antithesis, that perhaps is at the very heart of Greek thinking.