Authors: Daniel Bor
The Ravenous Brain: How the New Science of Consciousness Explains Our Insatiable Search for Meaning (3 page)
BOOK: The Ravenous Brain: How the New Science of Consciousness Explains Our Insatiable Search for Meaning
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Consciousness concerns itself only with the most meaningful mental constructions and is ever hungry to build new patterns over existing architectures. To help in this aim, it itches to combine and compare any objects in our awareness. How the brain supports consciousness closely mirrors these functions. Those specialist regions of the cortex that manage the processing endpoints of our senses—for instance, areas involved in recognizing faces, rather than merely the colors and textures that constitute a face—furnish our awareness with its specific content. But there is also a network of our most advanced general-purpose regions that directly draws in all manner of content from these specialist regions. This is the core network, incredibly densely connected together, both internally and across major regions throughout the brain. In this inner core, multiple sources of meaningful, potentially highly structured information are combined by ultra-fast brain rhythms. And this, neurally speaking, is how and where consciousness arises.
We now have a sufficiently clear understanding of which brain regions are involved in awareness, how they communicate, and so on, to propose mathematical models of consciousness based on neural architecture and information signature, and indeed such models are already being proposed. Simultaneously, new empirical methods of indexing levels of awareness are emerging. The blistering progress underway promises answers to the previously impenetrable question of how we gauge the conscious levels of beings that aren’t equipped to tell us about their consciousness, via language. This list of awkward subjects includes other animals, fetuses, babies, and—in the future—robots.
But there is another group of subjects who would call out even more pleadingly for a validation of their capacity for consciousness, if only they could. Patients with severe brain injury can appear to hover on the edge of awareness, with negligible behavioral signs that they are conscious. These patients’ doctors may naturally conclude that the ravages of injury or illness have truly robbed them of the capacity for awareness. But what if the damage includes the brain’s motor centers, leaving the patient utterly paralyzed? Are such patients secretly fully conscious, or has the extent of brain damage destroyed their capacity to experience the world, with paralysis therefore an irrelevance? How can we apply our scientific knowledge of consciousness to distinguish between these possibilities?
Our awareness gives us incredible gifts of understanding, though there is a heavy price to pay for such a vast consciousness. In the final sections of this book, I discuss the fragility of the organ that has grown so large and complex in order to support the amazing innovation machine of human consciousness. We are especially prone to serious brain injury, which can persistently rob us of awareness. Thankfully, though, many new techniques are arising to diagnose the levels of awareness that may still secretly reside in brain-damaged patients. Extensions of this research are beginning to offer us a chance to “hear” these patients, just by reading their brain signals, and for them to communicate with the outside world. Some emerging methods may even allow us to restore some degree of consciousness to patients in which it is clear that awareness is tragically absent as a result of injury.
Cases where severe brain injury leads to a persistent twilight of awareness are, thankfully, relatively rare. Unfortunately, though, the fragility of the human brain manifests very commonly, in more subtle forms. For optimum consciousness to occur, a complex interplay of various brain chemicals and activity between regions must be balanced just right. Some people have genes that make brain instabilities likely, and much of the population can be repeatedly battered by life’s stressful events, which further strains their intricate neural machinery. The result can easily be mental illness, a pandemic that gets far less focus than it deserves.
But vital new clues in both understanding and treatment are arising, with almost all psychiatric conditions being repainted in terms of disorders of awareness. Some psychiatric conditions involve a deeply deflated conscious space, like a car that can only crawl on a dangerously icy road. Such patients are desperate to move through life at a more normal pace. They frantically cling to any meager hint of a pattern that they perceive, like a driver who assumes that the only solution is to slam his foot on the gas pedal. This panicked response causes the car to skid out of control. Likewise, the patient’s mind freewheels, generating a multitude of paranoid, spurious innovations, which we call delusions.
Various techniques that literally expand and reinvigorate consciousness are being successfully applied to almost all psychiatric patient groups. However, this is not just the story of what consciousness is, and when it breaks down, but how we can apply this knowledge to aid our daily lives. For instance, many of these awareness building approaches could just as easily be adopted by all of us, both to reduce the daily weight of stress we endure and to enable us to view the world more directly, with fresh eyes. And, in time, we can learn tenderly to nurture a consciousness that is quiet, open, and ready to discover many beautiful new patterns around us.
1
Conceptual Conundrums of Consciousness
Philosophy
Many people share the easy intuition that our minds are somehow separate from our bodies. Most religions have encapsulated this notion via the supposition that we continue to live, in some form, after our bodies have perished, either in the afterlife or within another animal via reincarnation. Therefore, according to such theologies, the brain and body have nothing to do with our consciousness. But if this were really true, then how could an aspirin pacify my pain? How could that morning shot of espresso dispel my drowsiness? Is it really a remarkable coincidence that these drugs change my brain chemistry at the same time that specific aspects of my experience are altered?
If these examples of the physical world influencing our mental states are too subtle, then let me provide a more direct case. A few years ago I went into a brain scanner as a guinea pig for a friend and colleague, Martin Monti, who was trying out a new experiment. I’d been inside the scanner many times before—it is common practice for researchers to scan each other using rough-and-ready versions of a test before finalizing the experiment and bringing in volunteers from the general population. But this time was very different. This time, Martin was going to use the scanner as a telepathic tool.
Normally I would be performing a task in the scanner as I watched a series of images, and the complicated demands of imaging analysis meant that my brain activity could only be deciphered days later. But Martin was now using a newer procedure to carry out a far cruder analysis on the fly that would enable him to see my brain’s activity mere seconds after it occurred. The resulting picture of which regions had lit up would be far less detailed than what we normally viewed, but for his purposes they were sufficient.
This particular study involved him asking me various questions. If I wanted to answer yes, then I’d imagine looking around my house, which would activate the navigation region at the bottom of my brain (the parahip-pocampal place area). If I instead chose to answer no to his question, then I was to imagine playing tennis, which would activate the part of my motor cortex responsible for my hand and arm—at the top of my brain. These two tasks were deliberately designed to produce well-documented, robust, but diametrically opposite activation patterns, thus making them amenable to crude real-time analysis. Such a pattern of brain areas lighting up works consistently between subjects because our brains compute such tasks in very similar ways.
The experiment was part of a project to attempt to communicate with patients who might be fully conscious, but are unable to show this to the outside world because they have lost all motor control. But before subjecting severely ill patients to the inconvenience of a scan, Martin needed to hone the technique on guinea pigs like me.
During most former occasions when I lay in the scanner, I had felt relaxed—even a little bored—and occasionally struggled to stay awake (not that I would admit this to the researcher!). Now, though, I was surprised to find how excited I was. As the radiographer pushed the bed I was lying on into the large, white, fattened-donut shape of the fMRI scanner, so that only my feet were outside, I realized I was even a little nervous. It almost felt as if I were mentally naked—that Martin could actually watch my thoughts from the console room as he stared at the scanner monitor. I knew that this wasn’t really how it worked, but nevertheless I felt a palpable, exhilarating vulnerability. I was about to become more mentally transparent than almost anyone in the world had been before.
After the various loud beeps and clicks of the calibration scans, I heard Martin’s voice in my earphones asking me whether I had any siblings. For the next 30 seconds I recalled the various pieces of furniture and the shape and size of rooms in my home: meaning
yes
. Then I could relax for 30 seconds (the control) before repeating this minute-long cycle another four times. After the 5-minute train of piercing scanner beeps had stopped, the brief silence was broken by Martin’s voice in my headphones: “Okay—so you
do
have siblings. More than one?” Another 5 minutes passed as, in the non-rest periods, I imagined wild forehand swings with the tennis ball coming at me very fast:
no
. Then Martin’s voice again: “Okay, so you only have one sibling. A brother?” More house-browsing for yes. Martin correctly deciphered every answer I gave, simply by staring at a computer monitor that was representing my brain activity. In fact, he could normally do this within the first minute, with the other 4 minutes of trials seemingly only there for reassurance.
yes
. Then I could relax for 30 seconds (the control) before repeating this minute-long cycle another four times. After the 5-minute train of piercing scanner beeps had stopped, the brief silence was broken by Martin’s voice in my headphones: “Okay—so you
do
have siblings. More than one?” Another 5 minutes passed as, in the non-rest periods, I imagined wild forehand swings with the tennis ball coming at me very fast:
no
. Then Martin’s voice again: “Okay, so you only have one sibling. A brother?” More house-browsing for yes. Martin correctly deciphered every answer I gave, simply by staring at a computer monitor that was representing my brain activity. In fact, he could normally do this within the first minute, with the other 4 minutes of trials seemingly only there for reassurance.
Once the family questions had been exhausted, the conversation resorted to outright chattiness: “So do you think England is going to win the world cup match tonight?” Knowing little about soccer, except for the quality of the England team, I frantically started playing tennis to indicate:
not a chance
. We continued to have a conversation like this for about half an hour, with me thinking in these 30-second chunks, and Martin looking at the pattern of brain activity, and knowing very quickly whether I had answered yes or no. Admittedly, with a question every 5 minutes, it was not the most efficient conversation I’d ever had, but let me emphasize what was occurring: This conversation was being carried out without one of us engaging in any form of speech, gesticulation, or writing. I was answering in my mind by pretending to do various things, and Martin was detecting my answers by looking at my brain activity,
as I was thinking those answers
. When the radiographer helped me off the scanner bed and removed the various wires and equipment that had surrounded me, I paused for a moment and thought:
I have just participated in about the most definitive demonstration in existence that the mind is nothing more than the brain.
not a chance
. We continued to have a conversation like this for about half an hour, with me thinking in these 30-second chunks, and Martin looking at the pattern of brain activity, and knowing very quickly whether I had answered yes or no. Admittedly, with a question every 5 minutes, it was not the most efficient conversation I’d ever had, but let me emphasize what was occurring: This conversation was being carried out without one of us engaging in any form of speech, gesticulation, or writing. I was answering in my mind by pretending to do various things, and Martin was detecting my answers by looking at my brain activity,
as I was thinking those answers
. When the radiographer helped me off the scanner bed and removed the various wires and equipment that had surrounded me, I paused for a moment and thought:
I have just participated in about the most definitive demonstration in existence that the mind is nothing more than the brain.
It’s not as if this were the first time I had believed this, of course, having been heavily swayed by the evidence of the personality changes my father endured when the right side of his brain was swollen and constricted. But even that didn’t diminish the impact of what I’d experienced. I had successfully undergone science’s equivalent of telepathy; Martin had watched the inside of my skull as if it were a film—right at the time when I was co-opting my imagination to project the right images onto this “movie screen” of my brain.
PHILOSOPHY VERSUS SCIENCEThis book is shamelessly about the science of consciousness. Every chapter except this one will explore the evolutionary background and psychological and neural mechanisms of our own experiences. But questions about the relationship between the mind and body have been fiercely debated in philosophical circles for well over two thousand years. In fact, only in the past two decades has there been a clearly visible consciousness research field. It would therefore be remiss of me in a book on consciousness to ignore the major philosophical debates, which are such a well-established ancestral influence on consciousness science.
I will firmly assert, however, that these philosophical arguments, which rely so heavily on abstract logic for ammunition, as they neglect the scientific enterprise, provide very limited insights into consciousness, and can be positively misleading.
I’ll be centering on two key questions. First, is there nothing more to consciousness than brain activity, as my time in the scanner implied, or is awareness somehow independent of brains, bodies, and the rest of the physical world? And second, are we as mental beings nothing more than biological computers, or is there something special about the sensations we experience, and the meaning we attribute to the world, that could never be captured in software form?
DESCARTES AND THE MIND-BODY DUALITYThe seventeenth-century philosopher René Descartes is the landmark father figure of the philosophy of mind. In his most famous work,
Meditations on First Philosophy
, Descartes contemplated the possibility that a “malicious demon of the utmost power and cunning” had deceived him about the existence of all external things, including his own body. This is essentially also the premise of the film
The Matrix
, in which the hero, Neo, goes about his daily life believing that he is living in a twentieth-century U.S. city, only to be woken up from this extended dream to realize that it was a simulated reality that devious computers had been generating and wiring into his brain.
Meditations on First Philosophy
, Descartes contemplated the possibility that a “malicious demon of the utmost power and cunning” had deceived him about the existence of all external things, including his own body. This is essentially also the premise of the film
The Matrix
, in which the hero, Neo, goes about his daily life believing that he is living in a twentieth-century U.S. city, only to be woken up from this extended dream to realize that it was a simulated reality that devious computers had been generating and wiring into his brain.
BOOK: The Ravenous Brain: How the New Science of Consciousness Explains Our Insatiable Search for Meaning
2.9Mb size Format: txt, pdf, ePub
ads
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