Links for Keyword: Consciousness
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By Matthew R. Francis Possibly no subject in science has inspired more nonsense than quantum mechanics. Sure, it’s a complicated field of study, with a few truly mysterious facets that are not settled to everyone’s satisfaction after nearly a century of work. At the same time, though, using quantum to mean “we just don’t know” is ridiculous—and simply wrong. Quantum mechanics is the basis for pretty much all our modern technology, from smartphones to fluorescent lights, digital cameras to fiber-optic communications. If I had to pick a runner-up in the nonsense sweepstakes, it would be human consciousness, another subject with a lot of mysterious aspects. We are made of ordinary matter yet are self-aware, capable of abstractly thinking about ourselves and of recognizing others (including nonhumans) as separate entities with their own needs. As a physicist, I’m fascinated by the notion that our consciousness can imagine realities other than our own: The universe is one way, but we are perfectly happy to think of how it might be otherwise. I hold degrees in physics and have spent a lot of time learning and teaching quantum mechanics. Nonphysicists seem to have the impression that quantum physics is really esoteric, with those who study it spending their time debating the nature of reality. In truth, most of a quantum mechanics class is lots and lots of math, in the service of using a particle’s quantum state—the bundle of physical properties such as position, energy, spin, and the like—to describe the outcomes of experiments. Sure, there’s some weird stuff and it’s fun to talk about, but quantum mechanics is aimed at being practical (ideally, at least). © 2014 The Slate Group LLC.
Sam Kean For most of recorded history, human beings situated the mind — and by extension the soul — not within the brain but within the heart. When preparing mummies for the afterlife, for instance, ancient Egyptian priests removed the heart in one piece and preserved it in a ceremonial jar; in contrast, they scraped out the brain through the nostrils with iron hooks, tossed it aside for animals, and filled the empty skull with sawdust or resin. (This wasn’t a snarky commentary on their politicians, either—they considered everyone’s brain useless.) Most Greek thinkers also elevated the heart to the body’s summa. Aristotle pointed out that the heart had thick vessels to shunt messages around, whereas the brain had wispy, effete wires. The heart furthermore sat in the body’s center, appropriate for a commander, while the brain sat in exile up top. The heart developed first in embryos, and it responded in sync with our emotions, pounding faster or slower, while the brain just sort of sat there. Ergo, the heart must house our highest faculties. Meanwhile, though, some physicians had always had a different perspective on where the mind came from. They’d simply seen too many patients get beaned in the head and lose some higher faculty to think it all a coincidence. Doctors therefore began to promote a brain-centric view of human nature. And despite some heated debates over the centuries—especially about whether the brain had specialized regions or not—by the 1600s most learned men had enthroned the mind within the brain. A few brave scientists even began to search for that anatomical El Dorado: the exact seat of the soul within the brain. One such explorer was Swedish philosopher Emanuel Swedenborg, one of the oddest ducks to ever waddle across the stage of history. © 2014 Salon Media Group, Inc.
|By Christof Koch Quantum physicist Wolfgang Pauli expressed disdain for sloppy, nonsensical theories by denigrating them as “not even wrong,” meaning they were just empty conjectures that could be quickly dismissed. Unfortunately, many remarkably popular theories of consciousness are of this ilk—the idea, for instance, that our experiences can somehow be explained by the quantum theory that Pauli himself helped to formulate in the early 20th century. An even more far-fetched idea holds that consciousness emerged only a few thousand years ago, when humans realized that the voices in their head came not from the gods but from their own internal spoken narratives. Not every theory of consciousness, however, can be dismissed as just so much intellectual flapdoodle. During the past several decades, two distinct frameworks for explaining what consciousness is and how the brain produces it have emerged, each compelling in its own way. Each framework seeks to explain a vast storehouse of observations from both neurological patients and sophisticated laboratory experiments. One of these—the Integrated Information Theory—devised by psychiatrist and neuroscientist Giulio Tononi, which I have described before in these pages [see “Ubiquitous Minds”; Scientific American Mind, January/February 2014], uses a mathematical expression to represent conscious experience and then derives predictions about which circuits in the brain are essential to produce these experiences. [Full disclosure: I have worked with Tononi on this theory.] In contrast, the Global Workspace Model of consciousness moves in the opposite direction. Its starting point is behavioral experiments that manipulate conscious experience of people in a very controlled setting. It then seeks to identify the areas of the brain that underlie these experiences. © 2014 Scientific American
By CLYDE HABERMAN Her surname in Italian means “slave,” and is pronounced skee-AH-vo. Grim as it may be, the word could apply to Theresa Marie Schiavo, even with its Americanized pronunciation: SHY-vo. For 15 years, Terri Schiavo was effectively a slave — slave to an atrophied brain that made her a prisoner in her body, slave to bitter fighting between factions of her family, slave to seemingly endless rounds of court hearings, slave to politicians who injected themselves into her tragedy and turned her ordeal into a national morality play. To this day, the name Schiavo is virtually a synonym for epic questions about when life ends and who gets to make that determination. It would be nice to believe that since Ms. Schiavo’s death nine years ago, America has found clear answers. Of course it has not, as is evident in Retro Report’s exploration of the Schiavo case, the latest video documentary in a weekly series that examines major news stories from the past and their aftermath. Ms. Schiavo, a married woman living in St. Petersburg, Fla., was 26 years old when she collapsed on Feb. 25, 1990. While her potassium level was later found to be abnormally low, an autopsy drew no conclusion as to why she had lost consciousness. Whatever the cause, her brain was deprived of oxygen long enough to leave her in a “persistent vegetative state,” a condition that is not to be confused with brain death. She could breathe without mechanical assistance. But doctors concluded that she was incapable of thought or emotion. After her death on March 31, 2005, an autopsy determined that the brain damage was irreversible. Between her collapse — when she “departed this earth,” as her grave marker puts it — and her death — when she became “at peace” — the nation bore witness to an increasingly acrimonious battle between her husband, Michael Schiavo, and her parents, Robert and Mary Schindler. Mr. Schiavo wanted to detach the feeding tube that gave her nourishment. Terri never would have wanted to be kept alive that way, he said. The Schindlers insisted that the tube be kept in place. That, they said, is what their daughter would have wanted. To Mr. Schiavo, the woman he had married was gone. To the Schindlers, a sentient human was still in that body. © 2014 The New York Times Company
By DENISE GRADY People with severe brain injuries sometimes emerge from a coma awake but unresponsive, leaving families with painful questions. Are they aware? Can they think and feel? Do they have any chance of recovery? A new study has found that PET scans may help answer these wrenching questions. It found that a significant number of people labeled vegetative had received an incorrect diagnosis and actually had some degree of consciousness and the potential to improve. Previous studies using electroencephalogram machines and M.R.I. scanners have also found signs of consciousness in supposedly vegetative patients. “I think these patients are kind of neglected by both medicine and society,” said Dr. Steven Laureys, an author of the new study and the director of the Coma Science Group at the University of Liège in Belgium. “Many of them don’t even see a medical doctor or a specialist for years. So I think it’s very important to ask the question, are they unconscious?” In the United States, 100,000 to 300,000 people are thought to be minimally conscious, and an additional 25,000 are vegetative. In Belgium, the combined incidence of the two conditions is about 150 new cases per year, Dr. Laureys said. An article about the new research was published on Tuesday in The Lancet. Dr. Laureys and his colleagues studied 122 patients with brain injuries, including 41 who had been declared vegetative — awake but with no behavioral signs of awareness. People who are vegetative for a year are thought to have little or no chance of recovering, and the condition can become grounds for withdrawing medical treatment. Terri Schiavo, in a vegetative state for 15 years, died in 2005 in Florida after courts allowed the removal of her feeding tube. © 2014 The New York Times Company
Related chapters from BP7e: Chapter 18: Attention and Higher Cognition; Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior
Related chapters from MM:Chapter 14: Attention and Consciousness; Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 19497 - Posted: 04.16.2014
By Neuroskeptic A neuroscience paper published before Christmas drew my eye with the expansive title: “How Thoughts Give Rise to Action“ Subtitled “Conscious Motor Intention Increases the Excitability of Target-Specific Motor Circuits”, the article’s abstract was no less bold, concluding that: These results indicate that conscious intentions govern motor function… until today, it was unclear whether conscious motor intention exists prior to movement, or whether the brain constructs such an intention after movement initiation. The authors, Zschorlich and Köhling of the University of Rostock, Germany, are weighing into a long-standing debate in philosophy, psychology, and neuroscience, concerning the role of consciousness in controlling our actions. To simplify, one school of thought holds that (at least some of the time), our intentions or plans control our actions. Many people would say that this is what common sense teaches us as well. But there’s an alternative view, in which our consciously-experienced intentions are not causes of our actions but are actually products of them, being generated after the action has already begun. This view is certainly counterintuitive, and many find it disturbing as it seems to undermine ‘free will’. That’s the background. Zschorlich and Köhling say that they’ve demonstrated that conscious intentions do exist, prior to motor actions, and that these intentions are accompanied by particular changes in brain activity. They claim to have done this using transcranial magnetic stimulation (TMS), a way of causing a localized modulation of brain electrical activity.
Related chapters from BP7e: Chapter 18: Attention and Higher Cognition; Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 14: Attention and Consciousness; Chapter 5: The Sensorimotor System
Link ID: 19370 - Posted: 03.17.2014
by Tom Siegfried Max Planck, who shook the world with his discovery of quantum physics, also offered a warning. “One must be careful,” he said, “when using the word, real.” It was good advice. As physicists explored the quantum domain, they found that usual ideas about reality did not apply. Reality in the realm of atoms was nothing like the world of rocks and baseballs and planets, where Newton’s laws of motions ruled with rigor. Among atoms, the rules were more like Olympic ice skating judging, with unpredictable scores. Gradually physicists, engineers and even screenwriters became familiar with quantum weirdness and used it in lasers, computers and movie plots. Quantum reality might be crazy, but it’s our reality, and most scientists, anyway, have become more or less used to it. Nevertheless, Planck’s warning still applies. Perhaps the quantum picture of reality is another illusion, just like Newton’s was. Human insight into nature may not yet have penetrated reality’s ultimate veil. In other words, maybe reality always dresses itself up in Newtonian or Einsteinian or quantum clothing, and science hasn’t yet seen what reality looks like naked. And that might explain why nature has been able to protect so many of its mysteries from science’s prying eyes — mysteries like the identity of dark matter, the math describing quantum gravity, the mechanism underlying consciousness. And whether humans have free will. Maybe reality always dresses itself up in Newtonian or Einsteinian or quantum clothing, and science hasn’t yet seen what reality looks like naked. © Society for Science & the Public 2000 - 2013.
by Helen Thomson People in a vegetative state showed signs of awareness after electric brain stimulation – and minimally conscious people were able to communicate again TALK about an awakening. People who have been in a minimally conscious state for weeks or years have been temporarily roused using mild electrical stimulation. Soon after it was applied to their brains, 15 people with severe brain damage showed signs of consciousness, including moving their hands or following instructions using their eyes. Two people were even able to answer questions for 2 hours before drifting back into their previous uncommunicative state. "I don't want to give people false hope – these people weren't getting up and walking around – but it shows there is potential for the brain to recover functionality, even several years after damage," says Steven Laureys at the University of Liège in Belgium, who led the research. People with severe brain trauma often fall into a coma. If they "awaken", by showing signs of arousal but not awareness, they are said to be in a vegetative state. This can improve to a state of minimal consciousness, where they might show fluctuating signs of awareness, which come and go, but have no ability to communicate. External stimulation of the brain has been shown to increase arousal, awareness and aspects of cognition in healthy people. So Laureys and his colleagues wondered if it would do the same in people with severe brain damage. They used transcranial direct current stimulation (tDCS), which doesn't directly excite the brain, but uses low-level electrical stimulation to make neurons more or less likely to fire. © Copyright Reed Business Information Ltd.
by Tom Siegfried If freedom is just another word for nothing left to lose, then “free will” is just another phrase for ability to choose. Bad, wasn’t it? But if free will is an illusion, as many scientists and philosophers have argued, then you shouldn’t blame me. On the other hand, I do blame myself. Because like most bloggers, and possibly even the several dozen humans who don’t blog, I think I decided for myself what to write. Besides, as many investigators of this issue have pointed out, it’s not so obvious that free will is illusory now that quantum mechanics has inserted some randomness into nature. Sadly, though, that reasoning doesn’t get you very far. There’s randomness in the quantum world, all right, just like the unpredictable sequence of winning numbers on a roulette wheel. But in the long run all the numbers turn up about equally often. Free will isn’t worth much if you can’t use it to beat a casino. And as MIT physicist Scott Aaronson points out, quantum math is similar: It gives the odds about what various possible things will happen, and those odds are always predicted precisely. The probability distribution of results is always just what the quantum math says it will be. Aaronson doesn’t see any free will there. Still, the free will question has elicited some sophisticated musing from quantum physicists who like to contemplate the interface of mentality and physical reality. It seems reasonable enough to reexamine such an old question in the light of the latest understanding of the universe. It may be that modern physics can offer a perspective giving hope for those who like to make up their own mind. © Society for Science & the Public 2000 - 2013.
By Partha Mitra Leonardo Da Vinci, in his Treatise on Painting (Trattato della Pittura), advises painters to pay particular attention to the motions of the mind, moti mentali. “The movement which is depicted must be appropriate to the mental state of the figure,” he advises; otherwise the figure will be considered twice dead: “dead because it is a depiction, and dead yet again in not exhibiting motion either of the mind or of the body.” Francesco Melzi, student and friend to Da Vinci, compiled the Treatise posthumously from fragmented notes left to him. The vivid portrayal of emotions in the paintings from Leonardo’s school shows that his students learned to read the moti mentali of their subjects in exquisite detail. Associating an emotional expression of the face with a “motion of the mind” was an astonishing insight by Da Vinci and a surprisingly modern metaphor. Today we correlate specific patterns of electrochemical dynamics (i.e. “motions”) of the central nervous system, with emotional feelings. Consciousness, the substrate for any emotional feeling, is itself a “motion of the mind,” an ephemeral state characterized by certain dynamical patterns of electrical activity. Even if all the neurons, their constituent parts and neuronal circuitry remained structurally the same, a change in the dynamics can mean the difference between consciousness and unconsciousness. But what kind of motion is it? What are the patterns of electrical activity that correspond to our subjective state of being conscious, and why? Can they be measured and quantified? This is not only a theoretical or philosophical question but also one that is of vital interest to the anesthesiologist trying to regulate the level of consciousness during surgery, or for the neurologist trying to differentiate between different states of consciousness following brain trauma. © 2014 Scientific American
By JAMES GORMAN St. Louis — I knew I wouldn’t find my “self” in a brain scan. I also knew as I headed into the noisy torpedo tube of a souped-up M.R.I. machine at Washington University in St. Louis that unless there was something terribly wrong (“Igor, look! His head is filled with Bitcoins!”), I would receive no news of the particulars of how my brain was arranged. Even if I had been one of the 1,200 volunteers in the part of the Human Connectome Project being conducted there, I wouldn’t have gotten a report of my own personal connectome and what it meant. Once the 10 hours of scans and tests are finished, and 10 hours more of processing and analysis done, the data for each of the volunteers — all anonymous — becomes part of a database to help scientists develop tools so that one day such an individual report might be possible. Besides, I was just going through a portion of the process, to see what it was like. Even so, I do have this sense of myself as an individual, different from others in ways good, bad and inconsequential, and the pretty reasonable feeling that whatever a “self” is, it lies behind my eyes and between my ears. That’s where I feel that “I” live. So I couldn’t shake the sense that there would be something special in seeing my brain, even if I couldn’t actually spot where all the song lyrics I’ve memorized are stored, or locate my fondness for cooking and singing and my deep disappointment that I can’t carry a tune (though I can follow a recipe). So I climbed into the M.R.I. machine. I tried to hold my head perfectly still as I stared at a spot marked by a cross, tried to corral my fading memory to perform well on tests, curled my toes and moved my fingers so that muscle motion could be mapped, and wondered at the extraordinary noises M.R.I. machines make. © 2014 The New York Times Company
Related chapters from BP7e: Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior; Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 2: Cells and Structures: The Anatomy of the Nervous System; Chapter 14: Attention and Consciousness
Link ID: 19104 - Posted: 01.07.2014
By NORIMITSU ONISHI SAN FRANCISCO — It started out as an operation to treat an increasingly common medical problem in America, childhood sleep apnea. It has become an anguished fight over the fate of a 13-year-old girl who, though pronounced legally dead by doctors, remains alive in the opinion of her religious parents. Sam Singer, a spokesman for Children’s Hospital, called the deal a victory for the hospital, which will release the girl to the Alameda County coroner. The girl, Jahi McMath, was declared brain-dead after complications from surgery on Dec. 9 at Children’s Hospital Oakland, which wanted to remove her from a ventilator. But her heart continues to beat, and her family protested the removal in court, so she has remained connected to the machine. On Friday, amid acrimonious battles in three courts, an Alameda County Superior Court judge mediated an agreement that could allow the child to be moved to another facility willing to take her, even though the hospital has declared her dead. As arguments in the courts continue, the girl will remain connected to the ventilator at least until Tuesday, under the judge’s order. In the meantime, family members are scrambling to identify a facility that will accept the girl and doctors willing to carry out procedures that will keep her heart beating during the transfer. Nailah Winkfield, the girl’s mother, said she was hopeful that Friday’s agreement would facilitate her daughter’s move. © 2014 The New York Times Company
By Christof Koch I grew up in a devout and practicing Roman Catholic family with Purzel, a fearless and high-energy dachshund. He, as with all the other, much larger dogs that subsequently accompanied me through life, showed plenty of affection, curiosity, playfulness, aggression, anger, shame and fear. Yet my church teaches that whereas animals, as God's creatures, ought to be treated well, they do not possess an immortal soul. Only humans do. Even as a child, to me this belief felt intuitively wrong. These gorgeous creatures had feelings, just like I did. Why deny them? Why would God resurrect people but not dogs? This core Christian belief in human exceptionalism did not make any sense to me. Whatever consciousness and mind are and no matter how they relate to the brain and the rest of the body, I felt that the same principle must hold for people and dogs and, by extension, for other animals as well. It was only later, at university, that I became acquainted with Buddhism and its emphasis on the universal nature of mind. Indeed, when I spent a week with His Holiness the Dalai Lama earlier in 2013 [see “The Brain of Buddha,” Consciousness Redux; Scientific American Mind, July/August 2013], I noted how often he talked about the need to reduce the suffering of “all living beings” and not just “all people.” My readings in philosophy brought me to panpsychism, the view that mind (psyche) is found everywhere (pan). Panpsychism is one of the oldest of all philosophical doctrines extant and was put forth by the ancient Greeks, in particular Thales of Miletus and Plato. Philosopher Baruch Spinoza and mathematician and universal genius Gottfried Wilhelm Leibniz, who laid down the intellectual foundations for the Age of Enlightenment, argued for panpsychism, as did philosopher Arthur Schopenhauer, father of American psychology William James, and Jesuit paleontologist Teilhard de Chardin. It declined in popularity with the rise of positivism in the 20th century. © 2014 Scientific American,
By John Horgan New Year’s Day is approaching, a time when we—by which I mean I–brood over past failures and vow to improve ourselves: I will be less judgmental with my kids and more romantic with my girlfriend. I will stop binging on cookies and bad TV. (Why, oh why, do I keep watching Blacklist?) I will not assume that people who disagree with me are stupid or evil. Every time you choose one path over another, you are exercising your free will. Humanity has more freedom of choice now--and hence more free will--than in any previous era. At this time of year, I like to hearten my fellow Resolutionaries by defending the concept of free will, which has been attacked by various scientific pundits (who are just misguided, not stupid or evil). After all, how can you believe in resolutions unless you believe in free will? Below is an edited version of an essay that I originally wrote for The Chronicle of Higher Education. I never really thought about free will—or rather, I just took it for granted—until 1991, when I interviewed the late, great Francis Crick, who had switched from cracking the genetic code to solving the riddle of consciousness. With unnerving cheerfulness, Crick informed me that brain research is contradicting the notion of free will. Picking up a pen from his desk, he noted that even this simple act is underpinned and preceded by complex biochemical processes taking place below the level of consciousness. “What you’re aware of is a decision, but you’re not aware of what makes you do the decision,” Crick said. “It seems free to you, but it’s the result of things you’re not aware of.” I frowned, and Crick chuckled at my distress. © 2013 Scientific American,
By Elijah Wolfson Of the many ills that can befall the human body, brain damage is one of the most devastating – and confusing. When a person suffers from a traumatic brain injury that leaves him or her in an uncommunicative state, doctors and loved ones face one of medical science’s most confounding questions: How do we know when a person is still there? When is a body just a body? Those question only get more complicated with the startling news that the brains of some patients in a vegetative state appear to recognize familiar faces. The implications are mind-boggling. Brain death – when there is zero brain function – is both a medical and legal term, and it is, quite literally, death. But when there is some brain function left, the lines blur rather quickly. A brain-damaged patient may live for months and even years, in limbo: her eyes may open and she may sleep and wake up in what appears to be a normal cycle, but she has no meaningful interactions and shows no awareness of her surroundings – or herself. She is in what the medical community calls a “persistent vegetative state,” awake but unaware. It’s unlikely that she will ever recover, and if she does, she will probably face severe physical and neurological impairments. Not what most of us call living. Someone in a vegetative state raises an essential moral and ethical question and an often bitter debate: How much should we do to keep a body on autopilot going? The debate has intensified in recent years, as a few studies have found striking examples of vegetative patients who seem to be able, on some level, to communicate. “With changing paradigms of imaging and other techniques,” Dr. Karen Hirsch, a neurologist and neurosurgeon at the Stanford University Medical Center, told Newsweek, “we are learning that maybe some of these people do have some awareness.” © 2013 IBT MEDIA INC
By Deborah Kotz / Globe Staff Anyone who hears about the tragic death of a 13-year-old California girl after a routine tonsil-removal surgery has to feel for the grieving parents who don’t want her removed from life support. The McMaths refuse to believe that their daughter Jahi, who was declared brain dead more than a week ago, is truly dead because machines are keeping her other organs alive. “How could you not let me have my kid for Christmas?” said Nailah Winkfield, McMath’s mother, in an interview with local reporters. “And this is Children’s Hospital, supposed to be so compassionate, so loving, and I asked, can my daughter just live a few more days? Because she is living.” McMath was declared brain dead more than a week ago, and her family has been fighting with hospital staff at Children’s Hospital & Research Center in Oakland to keep her body in a viable state and have her provided with nutrition via a feeding tube. “To me, it just looks like she’s at peace and she’s resting,” said Jahi’s uncle Omari Sealey, “and when she’s done going through the traumatic stuff that her body’s going through right now, and she feels well enough, she’ll wake up.” But McMath is dead—as horrible as that is for her family to fathom—and leaving her body attached to machines is akin to allowing a corpse remain in a hospital bed without a proper burial. Perhaps hospitals should stop calling such care “life support” since it’s not actually supporting any living person, just a body. “This case is so sad it is almost beyond description,” wrote Arthur Caplan, head of the division of medical ethics at NYU Langone Medical Center in a blog he posted Thursday on the NBC News website. “But that fact should not be a reason to take the view that we don’t know what to do when someone is pronounced brain dead. Brain dead is dead.” © 2013 Boston Globe Media Partners, LLC
Related chapters from BP7e: Chapter 18: Attention and Higher Cognition; Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Related chapters from MM:Chapter 14: Attention and Consciousness; Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Link ID: 19057 - Posted: 12.21.2013
By MAGGIE KOERTH-BAKER More than a decade ago, a 43-year-old woman went to a surgeon for a hysterectomy. She was put under, and everything seemed to be going according to plan, until, for a horrible interval, her anesthesia stopped working. She couldn’t open her eyes or move her fingers. She tried to breathe, but even that most basic reflex didn’t seem to work; a tube was lodged in her throat. She was awake and aware on the operating table, but frozen and unable to tell anyone what was happening. Studies of anesthesia awareness are full of such horror stories, because administering anesthesia is a tightrope walk. Too much can kill. But too little can leave a patient aware of the procedure and unable to communicate that awareness. For every 1,000 people who undergo general anesthesia, there will be one or two who are not as unconscious as they seem — people who remember their doctors talking, and who are aware of the surgeon’s knife, even while their bodies remain catatonic and passive. For the unlucky 0.13 percent for whom anesthesia goes awry, there’s not really a good preventive. That’s because successful anesthetization requires complete unconsciousness, and consciousness isn’t something we can measure. There are tools that anesthesiologists use to get a pretty good idea of how well their drugs are working, but these systems are imperfect. For most patients receiving inhaled anesthesia, they’re no better at spotting awareness than dosing metrics developed half a century ago, says George Mashour, a professor of anesthesiology at the University of Michigan Medical School. There are two intertwined mysteries at work, Mashour told me: First, we don’t totally understand how anesthetics work, at least not on a neurological basis. Second, we really don’t understand consciousness — how the brain creates it, or even what, exactly, it is. © 2013 The New York Times Company
Related chapters from BP7e: Chapter 18: Attention and Higher Cognition; Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 14: Attention and Consciousness; Chapter 10: Biological Rhythms and Sleep
Link ID: 19025 - Posted: 12.11.2013
By Graham Lawton Patricia Churchland, a neurophilosopher at the University of California at San Diego, says our hopes, loves and very existence are just elaborate functions of a complicated mass of grey tissue. Accepting that can be hard, but what we know should inspire us, not scare us. Her most recent book is Touching a Nerve: The Self as Brain. Graham Lawton: You compare revelations in neuroscience with the discoveries that the Earth goes around the sun and that the heart is a pump. What do you think these ideas have in common? Patricia Churchland: They challenge a whole framework of assumptions about the way things are. For Christians, it was very important that the Earth was at the center of the universe. Similarly, many people believed that the heart was somehow what made us human. And it turned out it was just a pump made of meat. I think the same is true about realizing that when we're conscious, when we make decisions, when we go to sleep, when we get angry, when we're fearful, these are just functions of the physical brain. Coming to terms with the neural basis of who we are can be very unnerving. It has been called "neuroexistentialism," which really captures the essence of it. We're not in the habit of thinking about ourselves that way. GL: Why is it so difficult for us to see the reality of what we actually are? PC: Part of the answer has to do with the evolution of nervous systems. Is there any reason for a brain to know about itself? We can get along without knowing, just as we can get along without knowing that the liver is in there filtering out toxins. The wonderful thing, of course, is that science allows us to know. © 2013 The Slate Group, LLC.
by Bob Holmes Perseverance in the face of adversity is an admirable character trait – now it turns out you can conjure it up with a quick zap to a tiny spot in the brain. The discovery in two people with epilepsy was accidental but it is the first to show that simple brain stimulation can create rich, complex alterations of consciousness. Josef Parvizi, a neurologist at Stanford University in California, and his colleagues had implanted electrodes in the brains of two people with epilepsy to help identify the source of their seizures. In the course of their work, they noticed that an odd thing happened when they stimulated a region in the anterior midcingulate cortex – a part of the limbic system involved in emotion, processing, learning and memory. Both patients reported feeling a sense of foreboding, coupled with a determination to overcome whatever challenge they were about to face. During the stimulation, one patient reported feeling "worried that something bad is going to happen" but also noted that "it made me stronger". The other said he felt as if he were figuring out how to get through something. He likened it to driving your car when one of the tires bursts. You're only halfway to your destination and you have no option but to keep going forward. "You're like… am I gonna get through this?" he said (see video). He also reported a sense of urgency: "It was more of a positive thing like… push harder, push harder, push harder to try and get through this." One singular sensation In contrast, when the researchers applied a sham stimulation – going through exactly the same procedure, but with the current set to zero – neither volunteer reported feeling any specific sensations. Stimulation of other nearby regions of the brain less than 5 millimetres away also failed to produce the feelings of either foreboding or perseverance. © Copyright Reed Business Information Ltd.
Related chapters from BP7e: Chapter 18: Attention and Higher Cognition; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 14: Attention and Consciousness; Chapter 11: Emotions, Aggression, and Stress
Link ID: 19006 - Posted: 12.06.2013
By Neuroskeptic I am sitting reading a book. After a while, I get up and make a cup of coffee. I’ve been thinking about this scenario lately as I’ve pondered ‘what remains to be discovered’ in our understanding the brain. By this I mean, what (if anything) prevents neuroscience from at least sketching out an explanation for all of human behaviour? A complete explanation of any given behaviour – such as my reading a particular book – would be impossible, as it would require detailed knowledge of all my brain activity. But neuroscience could sketch an account of some stages of the reading. We have models for how my motor cortex and cerebellum might coordinate my fingers to turn the pages of my book. Other models try to make sense of the recognition of the letters by my visual cortex. This is what I mean by ‘beginning to account for’. We have theories that are not wholly speculative. While we don’t yet have the whole story of motor control or visual perception, we have made a start. Yet I’m not sure that we can even begin to explain: why did I stop what I was doing, get up, and make coffee at that particular time? The puzzle, it seems, does not lie in my actual choice to make some coffee (as opposed to not making it.) We could sketch an explanation for how, once the mental image (memory) of coffee ‘crossed my mind’, that image set off dopamine firing (i.e. I like coffee), and this dopamine, acting on corticostriatal circuits, selected the action of making coffee over the less promising alternatives. But why did that mental image of coffee cross my mind in the first place? And why did it do so just then, not thirty seconds before or afterwards?