Links for Keyword: Consciousness

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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

Related chapters from BP7e: Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 14: Attention and Consciousness
Link ID: 19063 - Posted: 12.23.2013

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.

Related chapters from BP7e: Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 14: Attention and Consciousness
Link ID: 19024 - Posted: 12.11.2013

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?

Related chapters from BP7e: Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 14: Attention and Consciousness
Link ID: 18957 - Posted: 11.23.2013

By Gary Stix The emerging academic discipline of neuroethics has been driven, in part, by the recognition that introducing brain scans as legal evidence is fraught with peril. Most neuroscientists think that a brain scan is unable to provide an accurate representation of the state of mind of a defendant or determine whether his frontal lobes predispose to some wanton action. The consensus view holds that studying spots on the wrinkled cerebral cortex that are bigger or smaller in some criminal offenders may hint at overarching insights into the roots of violence, but lack the requisite specificity to be used as evidence in any individual case. “I believe that our behavior is a production of activity in our brain circuits,” Steven E. Hyman of the Broad Institute of Harvard and MIT told a session at the American Association for the Advancement of Science’s annual meeting earlier this year. “But I would never tell a parole board to decide whether to release somebody or hold on to somebody, based on their brain scan as an individual, because I can’t tell what are the causal factors in that individual.” It doesn’t seem to really matter, though, what academic experts believe about the advisability of brain scans as Exhibit One at trial. The entry of neuroscience in the courtroom has already begun, big time. The introduction of a brain scan in a legal case was once enough to generate local headlines. No more. Hundreds of legal opinions each year have begun to invoke the science of mind and brain to bolster legal arguments—references not only to brain scans, but a range of studies that show that the amygdala is implicated in this or the anterior cingulate cortex is at fault for that. The legal establishment, in short, has begun a love affair with all things brain. © 2013 Scientific American

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: 18955 - Posted: 11.21.2013

by Linda Geddes Anaesthetics usually knock you out like a light. But by slowing the process down so that it takes 45 minutes to become totally unresponsive, researchers have discovered a new signature for unconsciousness. The discovery could lead to more personalised methods for administering anaesthetics and cut the risks associated with being given too high or too low a dose. It also sheds new light on what happens to our brain when we go under the knife. Hundreds of thousands of people are anaesthetised every day, yet researchers still don't fully understand what's going on in the anaesthetised brain. Nor is there a direct way of measuring when someone is truly unresponsive. Instead, anaesthetists rely on indirect measures such as heart and breathing rate, and monitoring reflexes. To investigate further, Irene Tracey and her colleagues at Oxford University slowed the anaesthesia process down. Instead of injecting the anaesthetic propofol in one go, which triggers unconsciousness in seconds, the drug was administered gradually so that it took 45 minutes for 16 volunteers to become fully anaesthetised. Their brain activity was monitored throughout using electroencephalography (EEG). The study was then repeated on 12 of these volunteers using functional magnetic resonance imaging (fMRI). EEG recordings revealed that before the volunteers became completely unresponsive to external stimuli they progressed through a sleep-like state characterised by slow-wave oscillations – a hallmark of normal sleep, in which neurons cycle between activity and inactivity. As the dose of anaesthetic built up, more and more neurons fell into this pattern, until a plateau was reached when no more neurons were recruited, regardless of the dose administered. © Copyright Reed Business Information Ltd.

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: 18836 - Posted: 10.26.2013

by Nora Schultz A SIMPLE bedside scan could reveal an active mind hidden inside an unresponsive body. The method provides another tool for recognising consciousness in people who have been wrongly diagnosed as being in a vegetative state. Tests are also under way to use it to monitor people under general anaesthetic, to make sure they do not regain consciousness during an operation. The technique builds on recent research into the nature of consciousness. "Information that is processed consciously typically recruits several brain regions at once," says Jean-Rémi King at the Brain and Spine Institute (ICM) in Paris, France. Other information that enters the brain triggers unconscious activity – for instance, the righting reflex that helps us retain balance when we are pushed – and it only tends to activate one brain area. King and his colleague Jacobo Sitt, also at the ICM, reasoned that they could spot consciousness in people simply by playing them a series of beeps and then searching electroencephalogram (EEG) brain scan data for evidence that signals from different brain regions fluctuated in the same way as each other, suggesting that they were sharing information. They performed their tests on 75 people in a vegetative state, 67 minimally conscious people, 24 people who had recently regained consciousness after a coma, and 14 healthy controls. By running the EEG data through statistics software, the researchers found differences between the patterns from people who were fully conscious, those in a vegetative state, and those who were minimally conscious (Current Biology, doi.org/n42). © Copyright Reed Business Information Ltd.

Related chapters from BP7e: Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 14: Attention and Consciousness
Link ID: 18772 - Posted: 10.10.2013

By Roy F. Baumeister It has become fashionable to say that people have no free will. Many scientists cannot imagine how the idea of free will could be reconciled with the laws of physics and chemistry. Brain researchers say that the brain is just a bunch of nerve cells that fire as a direct result of chemical and electrical events, with no room for free will. Others note that people are unaware of some causes of their behavior, such as unconscious cues or genetic predispositions, and extrapolate to suggest that all behavior may be caused that way, so that conscious choosing is an illusion. Scientists take delight in (and advance their careers by) claiming to have disproved conventional wisdom, and so bashing free will is appealing. But their statements against free will can be misleading and are sometimes downright mistaken, as several thoughtful critics have pointed out. Arguments about free will are mostly semantic arguments about definitions. Most experts who deny free will are arguing against peculiar, unscientific versions of the idea, such as that “free will” means that causality is not involved. As my longtime friend and colleague John Bargh put it once in a debate, “Free will means freedom from causation.” Other scientists who argue against free will say that it means that a soul or other supernatural entity causes behavior, and not surprisingly they consider such explanations unscientific. These arguments leave untouched the meaning of free will that most people understand, which is consciously making choices about what to do in the absence of external coercion, and accepting responsibility for one’s actions. Hardly anyone denies that people engage in logical reasoning and self-control to make choices. There is a genuine psychological reality behind the idea of free will. The debate is merely about whether this reality deserves to be called free will. Setting aside the semantic debate, let’s try to understand what that underlying reality is. © 2013 The Slate Group, LLC.

Related chapters from BP7e: Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 14: Attention and Consciousness
Link ID: 18713 - Posted: 09.28.2013

Joseph Brean U.S. President Barack Obama’s much-hyped BRAIN initiative to crack the mysteries of consciousness via a finely detailed map of the brain in action took its first big step this week, with the release of a strategy report that foresees “revolutionary advances” in the $100-million effort to “crack the brain’s code,” perhaps in as little as “a few years.” “We stand on the verge of a great journey into the unknown,” the report says, explicitly comparing BRAIN to the Apollo moon shot, and predicting it will “change human society forever.” As a grand challenge, Apollo was an unambiguous success, despite the vast expense and human costs, but there is a growing sense among scientists, if not legacy-minded politicians, that the road ahead for modern neuroscience will be pocked with disappointment, with more impenetrable mysteries than solvable problems. As the world approaches what some are calling “peak neuro,” after three decades of over-hyped “brain porn,” the optimistic hope is that Mr. Obama’s BRAIN project will lead to a detailed and dynamic map of the brain, and thus reveal both how it works and how it fails in such diseases as Alzheimer’s or autism. The pessimistic fear, however, is that the “speed of thought,” as Mr. Obama described it, is just too quick for our current brain imaging technologies, primarily functional magnetic resonance imaging (fMRI). As the anonymous blogger Neuroskeptic, a British brain scientist who tracks the misinterpretation of brain scan studies by both scientists and media, put it in an email, “there’s just as much hype and misrepresentation as ever.” The more we learn about the brain, the less we seem to know. With its potential overstated and its aspirations presented as foregone conclusions, the relatively new field of neuroscience is in a period of self-reflection, said Jackie Sullivan, a philosopher of neuroscience at Western University in London Ont. “The vast majority of neuroscientists are well aware that the goals going forward need to be more modest,” she said. © 2013 National Post

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: 18686 - Posted: 09.23.2013

by Andy Coghlan Parts of the brain may still be alive after a person's brain activity is said to have flatlined. When someone is in a deep coma, their brain activity can go silent. An electroencephalogram measuring this activity may eventually show a flatline, usually taken as a sign of brain death. However, while monitoring a patient who had been placed in a deep coma to prevent seizures following a cardiac arrest, Bogdan Florea, a physician at the Regina Maria Medical Centre in Cluj-Napoca, Romania, noticed a strange thing – some tiny intermittent bursts of activity were interrupting an otherwise flatline signal, each lasting a few seconds. He asked Florin Amzica of the University of Montreal in Canada and his colleagues to investigate what might be happening. To imitate what happened in the patient, Amzica's team put cats into a deep coma using a high dose of anaesthesia. While EEG recordings taken from the surface of the brain – the cortex – showed a flatline, recordings from deep-brain electrodes revealed tiny bursts of activity originating in the hippocampus, responsible for memory and learning, which spread within minutes to the cortex. "These ripples build up a synchrony that rises in a crescendo to reach a threshold where they can spread beyond the hippocampus and trigger activity in the cortex," says Amzica. © Copyright Reed Business Information Ltd.

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: 18683 - Posted: 09.21.2013

by Sara Reardon It can be nearly impossible to know what is happening in the mind of someone who has experienced a severe brain injury, but two new methods could offer some clues. Together, they provide not only a better indication of consciousness but also a more effective way to communicate with some vegetative people. The way that a seemingly unconscious person behaves does not always reflect their mental state. Someone in a completely vegetative state may still be able to smile simply through reflex, while a perfectly alert person may be left unable to do so if a brain injury has affected their ability to move. So a different way to assess mental state is needed. Marcello Massimini at the University of Milan in Italy and his colleagues have developed a possible solution by stimulating brains with an electromagnetic pulse and then measuring the response. The pulse acts like striking a bell, they say, and neurons across the entire brain continue to "ring" in a specific wave pattern, depending on how active the connections between individual brain cells are. The team used this method to assess 20 people with brain injuries who were either in a vegetative state, in a minimally conscious state, or in the process of emerging from a coma. The team compared the patterns from these people with the patterns recorded from 32 healthy people who were awake, asleep or under anaesthesia. In each of the distinct states of consciousness, the researchers found, the neurons "shook" in a distinctive pattern in response to the electromagnetic pulse. © Copyright Reed Business Information Ltd

Related chapters from BP7e: Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 14: Attention and Consciousness
Link ID: 18517 - Posted: 08.17.2013

Kelly Servick Consciousness isn’t easy to define, but we know it when we experience it. It’s not so simple to decide when someone else is conscious, however, as doctors must sometimes do with patients who have suffered traumatic brain injury. Now, researchers have come up with an approach that uses the brain’s response to magnetic stimulation to judge a person’s awareness, reducing it to a numerical score they call an index of consciousness. “You’re kind of banging on the brain and listening to the echo,” says Anil Seth, a neuroscientist at the Sackler Centre for Consciousness Science at the University of Sussex in the United Kingdom who was not involved in the work. Faced with an unresponsive patient, clinicians do their best to determine whether the person is conscious. Through sound, touch, and other stimuli, they try to provoke verbal responses, slight finger movements, or just a shifting gaze. Yet some conscious patients simply can’t move or speak; an estimated 40% of those initially judged to be completely unaware are later found to have some level of consciousness. Recently, physicians seeking to resolve a patient’s conscious state have gone right to the source, searching for signs of awareness using brain imaging or recording electrical activity of neurons. Most of these approaches define a conscious brain as an integrated brain, where groups of cells in many different regions activate to form a cohesive pattern, explains Marcello Massimini, a neurophysiologist at the University of Milan in Italy. “But that’s not enough,” he says. Sometimes even an unconscious brain looks highly integrated. For example, stimulating the brain of a sleeping person can create a huge wave of activity that “propagates like a ripple in water.” It’s a highly synchronized, widespread pattern, but it’s not consciousness, he says, and so this measure is often unreliable for diagnosis. © 2012 American Association for the Advancement of Science.

Related chapters from BP7e: Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 14: Attention and Consciousness
Link ID: 18515 - Posted: 08.15.2013

By Gary Stix Unraveling the mystery of consciousness remains perhaps the biggest challenge in all neuroscience, so big and amorphous that most brain scientists won’t go near the topic, leaving philosophers to speculate about the a prioris. Even defining what consciousness is quickly devolves into lengthy and often ponderous treatises. The World Science Festival assembled a panel of luminaries who will attempt to make sense of this sprawling theme in the allotted 90 minutes. They included Mélanie Boly, a researcher and physician who has performed studies on minimally conscious patients; Christof Koch, a leading researcher on the neural basis of consciousness; Colin McGinn, known for his work on the philosophy of mind, and Nicholas Schiff, a physician-scientist who specializes in disorders of consciousness. Click below here to see these leading lights gathered at NYU’s Skirball Center for the Performing Arts on May 30 to take on whether Homo sapiens is the only conscious species, the question of whether consciousness transcends the physical boundaries of the brain, and an exploration of the biochemical processes that underlie the life of the mind. The session, entitled “The Whispering Mind: The Enduring Conundrum of Consciousness,” is moderated by ABC Nightline co-anchor Terry Moran. © 2013 Scientific American

Related chapters from BP7e: Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 14: Attention and Consciousness
Link ID: 18212 - Posted: 06.01.2013

Posted by Gary Marcus A few weeks ago, while staying with my in-laws, my four-month-old son woke up at two-thirty in the morning. He was hungry, and, knowing that he would not be coaxed back to sleep without a bottle, I brought him downstairs to the kitchen, where his crying stopped abruptly. He clearly recognized that he had arrived in an unfamiliar place, and he became fully absorbed in understanding where he was and how he’d gotten there. He was searingly alert; he craned his head and his eyes darted around. The eight minutes or so that it took it to warm the bottle, usually a time of intense complaint, passed with hardly a peep. I became convinced that, for the first time, my son was fully, consciously aware of his surroundings. As a scientist, I realize that my experience was subjective. But the leading scientific journal, Science, just published the results of an experiment that endeavored to look objectively at the rudiments of consciousness in infants. This work, conducted by the cognitive psychologists Sid Kouider, Stanislas Dehaene, and Ghislaine Dehaene-Lambertz, is an examination of brain waves in babies between five and fifteen months old, aimed at constructing what the scientists refer to as a “biological signature of consciousness.” The background of this experiment is a theory called the “global workspace” model of consciousness, according to which perceptual awareness involves two stages of neural activity. The first is a purely sensory activation, typically in the back of the brain. The second stage reflects a kind of “ignition,” and is achieved only for stimuli that are consciously perceived. © 2013 Condé Nast.

Related chapters from BP7e: Chapter 18: Attention and Higher Cognition; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 14: Attention and Consciousness; Chapter 13: Memory, Learning, and Development
Link ID: 18209 - Posted: 05.30.2013

By Ferris Jabr On any given day, millions of conversations reverberate through New York City. Poke your head out a window overlooking a busy street and you will hear them: all those overlapping sentences, only half-intelligible, forming a dense acoustic mesh through which escapes an exclamation, a buoyant laugh, a child’s shrill cry now and then. Every spoken consonant and vowel begins as an internal impulse. Electrical signals crackle along branching neurons in brain regions specialized for language and movement; further pulses spread across facial nerves, surge toward the throat and chest and zip down the spine. The diaphragm contracts—pulling air into the lungs—and relaxes, pushing air into that birdcage of calcium and cartilage—the larynx—within which wings of tissue draw near one another and hum. As this vibrating air enters the mouth, the tongue guides its flow and the lips give each breath a final shape and sound. Liberated syllables travel between one person and another in waves of colliding air molecules. All these conversations are matched in number and complexity by much more elusive discourses. The human brain loves soliloquy. Even when speaking with others—and especially when alone—we continually talk to ourselves in our heads. Such speech does not require the bellows in the chest, quivering flaps of tissue in the throat or a nimble tongue; it does not need to disturb even one hair cell in our ears, nor a single particle of air. We can speak to ourselves without making a sound. Stick your head out that same window above the crowded street and you will hear nothing of what people are saying to themselves privately. All that inner dialogue remains submerged beneath the ocean of human speech, like a novel written in invisible ink behind the text of another book. © 2013 Scientific American,

Related chapters from BP7e: Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 14: Attention and Consciousness
Link ID: 18095 - Posted: 04.30.2013

by Caroline Williams When it comes to making decisions, it seems that the conscious mind is the last to know. We already had evidence that it is possible to detect brain activity associated with movement before someone is aware of making a decision to move. Work presented this week at the British Neuroscience Association (BNA) conference in London not only extends it to abstract decisions, but suggests that it might even be possible to pre-emptively reverse a decision before a person realises they've made it. In 2011, Gabriel Kreiman of Harvard University measured the activity of individual neurons in 12 people with epilepsy, using electrodes already implanted into their brain to help identify the source of their seizures. The volunteers took part in the "Libet" experiment, in which they press a button whenever they like and remember the position of a second hand on a clock at the moment of decision. Kreiman discovered that electrical activity in the supplementary motor area, involved in initiating movement, and in the anterior cingulate cortex, which controls attention and motivation, appeared up to 5 seconds before a volunteer was aware of deciding to press the button (Neuron, doi.org/btkcpz). This backed up earlier fMRI studies by John-Dylan Haynes of the Bernstein Center for Computational Neuroscience in Berlin, Germany, that had traced the origins of decisions to the prefrontal cortex a whopping 10 seconds before awareness (Nature Neuroscience, doi.org/cs3rzv). "It's always nice when two lines of research converge and to know that what we see with fMRI is actually there in the neurons," says Haynes. © Copyright Reed Business Information Ltd.

Related chapters from BP7e: Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 14: Attention and Consciousness
Link ID: 18021 - Posted: 04.11.2013

Kerri Smith The experiment helped to change John-Dylan Haynes's outlook on life. In 2007, Haynes, a neuroscientist at the Bernstein Center for Computational Neuroscience in Berlin, put people into a brain scanner in which a display screen flashed a succession of random letters1. He told them to press a button with either their right or left index fingers whenever they felt the urge, and to remember the letter that was showing on the screen when they made the decision. The experiment used functional magnetic resonance imaging (fMRI) to reveal brain activity in real time as the volunteers chose to use their right or left hands. The results were quite a surprise. "The first thought we had was 'we have to check if this is real'," says Haynes. "We came up with more sanity checks than I've ever seen in any other study before." The conscious decision to push the button was made about a second before the actual act, but the team discovered that a pattern of brain activity seemed to predict that decision by as many as seven seconds. Long before the subjects were even aware of making a choice, it seems, their brains had already decided. As humans, we like to think that our decisions are under our conscious control — that we have free will. Philosophers have debated that concept for centuries, and now Haynes and other experimental neuroscientists are raising a new challenge. They argue that consciousness of a decision may be a mere biochemical afterthought, with no influence whatsoever on a person's actions. According to this logic, they say, free will is an illusion. "We feel we choose, but we don't," says Patrick Haggard, a neuroscientist at University College London. © 2013 Nature Publishing Group

Related chapters from BP7e: Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 14: Attention and Consciousness
Link ID: 17988 - Posted: 04.05.2013

by Julia Sklar IT IS a nightmare situation. A person diagnosed as being in a vegetative state has an operation without anaesthetic because they cannot feel pain. Except, maybe they can. Alexandra Markl at the Schön clinic in Bad Aibling, Germany, and colleagues studied people with unresponsive wakefulness syndrome (UWS) – also known as vegetative state – and identified activity in brain areas involved in the emotional aspects of pain. People with UWS can make reflex movements but can't show subjective awareness. There are two distinct neural networks that work together to create the sensation of pain. The more basic of the two – the sensory-discriminative network – identifies the presence of an unpleasant stimulus. It is the affective network that attaches emotions and subjective feelings to the experience. Crucially, without the activity of the emotional network, your brain detects pain but won't interpret it as unpleasant. Using PET scans, previous studies have detected activation in the sensory-discriminative network in people with UWS but their findings were consistent with a lack of subjective awareness, the hallmark of the condition. Now Markl and her colleagues have found evidence of activation in the affective or emotional network too (Brain and Behavior, doi.org/kfs). © Copyright Reed Business Information Ltd.

Related chapters from BP7e: Chapter 18: Attention and Higher Cognition; Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 14: Attention and Consciousness; Chapter 5: The Sensorimotor System
Link ID: 17839 - Posted: 02.23.2013