Chapter 14. Attention and Consciousness
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By Smitha Mundasad Health reporter, BBC News Scientists say a part of the brain, smaller than a pea, triggers the instinctive feeling that something bad is about to happen. Writing in the journal PNAS, they suggest the habenula plays a key role in how humans predict, learn from and respond to nasty experiences. And they question whether hyperactivity in this area is responsible for the pessimism seen in depression. They are now investigating whether the structure is involved in the condition. Animal studies have shown that the habenula fires up when subjects expect or experience adverse events, But in humans this tiny structure (less than 3mm in diameter) has proved difficult to see on scans. Inventing a technique to pinpoint the area, scientists at University College London put 23 people though MRI scanners to monitor their brain activity. Participants were shown a range of abstract pictures. A few seconds later, the images were linked to either punishment (painful electric shocks), reward (money) or neutral responses. For some images, a punishment or reward followed each time but for others this varied - leaving people uncertain whether they were going to feel pain or not. And when people saw pictures associated with shocks the habenula lit up. And the more certain they were a picture was going to result in a punishment, the stronger and faster the activity in this area. Scientists suggests the habenula is involved in helping people learn when it is best to stay away from something and may also signal just how bad a nasty event is likely to be. BBC © 2014
By KATE MURPHY ONE of the biggest complaints in modern society is being overscheduled, overcommitted and overextended. Ask people at a social gathering how they are and the stock answer is “super busy,” “crazy busy” or “insanely busy.” Nobody is just “fine” anymore. When people aren’t super busy at work, they are crazy busy exercising, entertaining or taking their kids to Chinese lessons. Or maybe they are insanely busy playing fantasy football, tracing their genealogy or churning their own butter. And if there is ever a still moment for reflective thought — say, while waiting in line at the grocery store or sitting in traffic — out comes the mobile device. So it’s worth noting a study published last month in the journal Science, which shows how far people will go to avoid introspection. “We had noted how wedded to our devices we all seem to be and that people seem to find any excuse they can to keep busy,” said Timothy Wilson, a psychology professor at the University of Virginia and lead author of the study. “No one had done a simple study letting people go off on their own and think.” The results surprised him and have created a stir in the psychology and neuroscience communities. In 11 experiments involving more than 700 people, the majority of participants reported that they found it unpleasant to be alone in a room with their thoughts for just 6 to 15 minutes. Moreover, in one experiment, 64 percent of men and 15 percent of women began self-administering electric shocks when left alone to think. These same people, by the way, had previously said they would pay money to avoid receiving the painful jolt. It didn’t matter if the subjects engaged in the contemplative exercise at home or in the laboratory, or if they were given suggestions of what to think about, like a coming vacation; they just didn’t like being in their own heads. © 2014 The New York Times Company
By MICHAEL INZLICHT and SUKHVINDER OBHI I FEEL your pain. These words are famously associated with Bill Clinton, who as a politician seemed to ooze empathy. A skeptic might wonder, though, whether he truly was personally distressed by the suffering of average Americans. Can people in high positions of power — presidents, bosses, celebrities, even dominant spouses — easily empathize with those beneath them? Psychological research suggests the answer is no. Studies have repeatedly shown that participants who are in high positions of power (or who are temporarily induced to feel powerful) are less able to adopt the visual, cognitive or emotional perspective of other people, compared to participants who are powerless (or are made to feel so). For example, Michael Kraus, a psychologist now at the University of Illinois at Urbana-Champaign, and two colleagues found that among full-time employees of a public university, those who were higher in social class (as determined by level of education) were less able to accurately identify emotions in photographs of human faces than were co-workers who were lower in social class. (While social class and social power are admittedly not the same, they are strongly related.) Why does power leave people seemingly coldhearted? Some, like the Princeton psychologist Susan Fiske, have suggested that powerful people don’t attend well to others around them because they don’t need them in order to access important resources; as powerful people, they already have plentiful access to those. We suggest a different, albeit complementary, reason from cognitive neuroscience. On the basis of a study we recently published with the researcher Jeremy Hogeveen, in the Journal of Experimental Psychology: General, we contend that when people experience power, their brains fundamentally change how sensitive they are to the actions of others. © 2014 The New York Times Company
Posted by Katie Langin In a battle of wits, could a bird outsmart a kindergartner? Don’t be too quick to say no: One clever young bird solved a problem that has stumped 5-year-old children, according to a new study. The bird—a New Caledonian crow named Kitty—figured out that dropping rocks in one water-filled tube was the key to raising the water level in another, seemingly unconnected tube, giving her access to a floating morsel of meat. To solve this problem, Kitty needed to decipher a confusing cause-and-effect relationship, basically akin to figuring out that if you flip a switch on the wall, a ceiling light will turn on. This mental ability was once thought to be restricted to humans, but causal reasoning—the ability to understand cause and effect—has now been identified in a handful of animals, from chimpanzees to rats. Crows are the Einsteins of the bird world, renowned for their ability to make tools and solve complex puzzles. (Watch a video of a New Caledonian crow solving problems.) Their impressive mental capacity was even apparent to the ancient Greeks. In one of Aesop’s fables, a thirsty crow is presented with a dilemma when he cannot reach the water at the bottom of a pitcher. He figures out that the water level rises when he drops pebbles into the pitcher, and many pebbles later he is rewarded with a drink. As it turns out, there’s some truth to this fictional story. A study published earlier this year reported that New Caledonian crows will place rocks in water-filled tubes if they can’t reach a piece of meat that is attached to a floating cork. © 1996-2013 National Geographic Society.
by Douglas Heaven Hijacking how neurons of nematode worms are wired is the first step in an approach that could revolutionise our understanding of brains and consciousness CALL it the first brain hack. The humble nematode worm has had its neural connections hot-wired, changing the way it responds to salt and smells. As well as offering a way to create souped-up organisms, changing neural connectivity could one day allow us to treat brain damage in people by rerouting signals around damaged neurons. What's more, it offers a different approach to probing brain mysteries such as how consciousness arises from wiring patterns – much like exploring the function of an electronic circuit by plugging and unplugging cables. In our attempts to understand the brain, a lot of attention is given to neurons. A technique known as optogenetics, for example, lets researchers study the function of individual neurons by genetically altering them so they can be turned on and off by a light switch. But looking at the brain's connections is as important as watching the activity of neurons. Higher cognitive functions, such as an awareness of our place in the world, do not spring from a specific area, says Fani Deligianni at University College London. Deligianni and her colleagues are developing imaging techniques to map the brain's connections, as are other groups around the world (see "Start with a worm..."). "From this we can begin to answer some of the big questions about the workings of the brain and consciousness which seem to depend on connectivity," she says. Tracing how the brain is wired is a great first step but to find out how this linking pattern produces a particular behaviour we need to be able to see how changing these links affects brain function. This is what a team led by William Schafer at the MRC Laboratory of Molecular Biology in Cambridge, UK, is attempting. © Copyright Reed Business Information Ltd.
By Neuroskeptic An entertaining paper just out in Frontiers in Systems Neuroscience offers a panoramic view of the whole of neuroscience: Enlarging the scope: grasping brain complexity The paper is remarkable not just for its content but also for its style. Some examples: How does the brain work? This nagging question is an habitué from the top ten lists of enduring problems in Science’s grand challenges. Grasp this paradox: how is one human brain – a chef d’oeuvre of complexity honed by Nature – ever to reach such a feast as to understand itself? Where one brain may fail at this notorious philosophical riddle, may be a strong and diversely-skilled army of brains may come closer. Or It remains an uneasy feeling that so much of Brain Science is built upon the foundation of a pair of neurons, outside the context of their networks, and with two open-ended areas of darkness at either of their extremities that must be thought of as the entire remainder of the organism’s brain (and body). And my favorite: As humans tend to agree, increased size makes up for smarter brains (disclosure: both authors are human) I love it. I’m not sure I understand it, though. The authors, Tognoli and Kelso, begin by framing a fundamental tension between directed information transfer and neural synchrony, pointing out that neurons firing perfectly in synch with each other could not transfer information between themselves.
Link ID: 19829 - Posted: 07.15.2014
|By Roni Jacobson Prozac, Paxil, Celexa, Zoloft, Lexapro. These so-called selective serotonin reuptake inhibitors (SSRIs) are among the most widely prescribed drugs in the U.S. Although they are typically used to treat depression and anxiety disorders, they are also prescribed off-label for conditions such as chronic pain, premature ejaculation, bulimia, irritable bowel syndrome, premenstrual syndrome and hot flashes. Even if you have never taken an SSRI, chances are you know someone who has. About one in every 10 American adults is being prescribed one now. For women aged 40 to 59 years old, the proportion increases to one in four. SSRIs block the body from reabsorbing serotonin, a neurotransmitter mostly found in the brain, spinal cord and digestive tract whose roles include regulation of mood, appetite, sexual function and sleep. Specifically, SSRIs bind to the protein that carries serotonin between nerve cells—called SERT, for serotonin transporter—intercepting it before it can escort the released neurotransmitter back into the cell. This action leaves more active serotonin in the body, a chemical effect that is supposed to spur feelings of happiness and well-being. But there are hints that SSRIs are doing something other than simply boosting serotonin levels. First, people vary in their response to SSRIs: Studies have shown that the drugs are not very effective for mild to moderate depression, but work well when the disorder is severe. If low serotonin were the only culprit in depression, SSRIs would be more uniformly helpful in alleviating symptoms. Second, it takes weeks after starting an SSRI for depression and anxiety to lift even though changes in serotonin ought to happen pretty much right away. © 2014 Scientific American
Sara Reardon For chimps, nature and nurture appear to contribute equally to intelligence. Smart chimpanzees often have smart offspring, researchers suggest in one of the first analyses of the genetic contribution to intelligence in apes. The findings, published online today in Current Biology1, could shed light on how human intelligence evolved, and might even lead to discoveries of genes associated with mental capacity. A team led by William Hopkins, a psychologist at Georgia State University in Atlanta, tested the intelligence of 99 chimpanzees aged 9 to 54 years old, most of them descended from the same group of animals housed at the Yerkes National Primate Research Center in Atlanta. The chimps faced cognitive challenges such as remembering where food was hidden in a rotating object, following a human’s gaze and using tools to solve problems. A subsequent statistical analysis revealed a correlation between the animals' performance on these tests and their relatedness to other chimpanzees participating in the study. About half of the difference in performance between individual apes was genetic, the researchers found. In humans, about 30% of intelligence in children can be explained by genetics; for adults, who are less vulnerable to environmental influences, that figure rises to 70%. Those numbers are comparable to the new estimate of the heritability of intelligence across a wide age range of chimps, says Danielle Posthuma, a behavioural geneticist at VU University in Amsterdam, who was not involved in the research. “This study is much overdue,” says Rasmus Nielsen, a computational biologist at the University of California, Berkeley. “There has been enormous focus on understanding heritability of intelligence in humans, but very little on our closest relatives.” © 2014 Nature Publishing Group
By Dominic Basulto It turns out that the human brain may not be as mysterious as it has always seemed to be. Researchers at George Washington University, led by Mohamad Koubeissi, may have found a way to turn human consciousness on and off by targeting a specific region of the brain with electrical currents. For brain researchers, unlocking the mystery of human consciousness has always been viewed as one of the keys for eventually building an artificial brain, and so this could be a big win for the future of brain research. What the researchers did was deliver a serious of high frequency electrical impulses to the claustrum region of the brain in a woman suffering from epilepsy. Before the electric shocks, the woman was capable of writing and talking. During the electric shocks, the woman faded out of consciousness, and started staring blankly into space, incapable of even the most basic sensory functions. Even her breathing slowed. As soon as the electrical shocks stopped, the woman immediately regained her sensory skills with no memory of the event. The researchers claim that this test case is evidence of being able to turn consciousness on and off. Granted, there’s a lot still to be done. That George Washington test, for example, has only been successfully performed on one person. And that woman had already had part of her hippocampus removed, so at least one researcher says the whole experiment must be interpreted carefully. There have been plenty of scientific experiments that have been “one and done,” so it remains to be seen whether these results can be replicated again.
Link ID: 19817 - Posted: 07.12.2014
By ALEX HALBERSTADT Dr. Vint Virga likes to arrive at a zoo several hours before it opens, when the sun is still in the trees and the lanes are quiet and the trash cans empty. Many of the animals haven’t yet slipped into their afternoon malaise, when they retreat, appearing to wait out the heat and the visitors and not do much of anything. Virga likes to creep to the edge of their enclosures and watch. He chooses a spot and tries not to vary it, he says, “to give the animals a sense of control.” Sometimes he watches an animal for hours, hardly moving. That’s because what to an average zoo visitor looks like frolicking or restlessness or even boredom looks to Virga like a lot more — looks, in fact, like a veritable Russian novel of truculence, joy, sociability, horniness, ire, protectiveness, deference, melancholy and even humor. The ability to interpret animal behavior, Virga says, is a function of temperament, curiosity and, mostly, decades of practice. It is not, it turns out, especially easy. Do you know what it means when an elephant lowers her head and folds her trunk underneath it? Or when a zebra wuffles, softly blowing air between her lips; or when a colobus monkey snuffles, sounding a little like a hog rooting in the mud; or when a red fox screams, sounding disconcertingly like an infant; or when red fox kits chatter at one another; or when an African wild dog licks and nibbles at the lips of another; or when a California sea lion resting on the water’s surface stretches a fore flipper and one or both rear flippers in the air, like a synchronized swimmer; or when a hippopotamus “dung showers” by defecating while rapidly flapping its tail? Virga knows, because it is his job to know. He is a behaviorist, and what he does, expressed plainly, is see into the inner lives of animals. The profession is an odd one: It is largely unregulated, and declaring that you are an expert is sometimes enough to be taken for one. Most behaviorists are former animal trainers; some come from other fields entirely. Virga happens to be a veterinarian, very likely the only one in the country whose full-time job is tending to the psychological welfare of animals in captivity. © 2014 The New York Times Company
|By Ferris Jabr You know the exit is somewhere along this stretch of highway, but you have never taken it before and do not want to miss it. As you carefully scan the side of the road for the exit sign, numerous distractions intrude on your visual field: billboards, a snazzy convertible, a cell phone buzzing on the dashboard. How does your brain focus on the task at hand? To answer this question, neuroscientists generally study the way the brain strengthens its response to what you are looking for—jolting itself with an especially large electrical pulse when you see it. Another mental trick may be just as important, according to a study published in April in the Journal of Neuroscience: the brain deliberately weakens its reaction to everything else so that the target seems more important in comparison. Cognitive neuroscientists John Gaspar and John McDonald, both at Simon Fraser University in British Columbia, arrived at the conclusion after asking 48 college students to take attention tests on a computer. The volunteers had to quickly spot a lone yellow circle among an array of green circles without being distracted by an even more eye-catching red circle. All the while the researchers monitored electrical activity in the students' brains using a net of electrodes attached to their scalps. The recorded patterns revealed that their brains consistently suppressed reactions to all circles except the one they were looking for—the first direct evidence of this particular neural process in action. © 2014 Scientific American
Link ID: 19788 - Posted: 07.03.2014
by Helen Thomson ONE moment you're conscious, the next you're not. For the first time, researchers have switched off consciousness by electrically stimulating a single brain area. Scientists have been probing individual regions of the brain for over a century, exploring their function by zapping them with electricity and temporarily putting them out of action. Despite this, they have never been able to turn off consciousness – until now. Although only tested in one person, the discovery suggests that a single area – the claustrum – might be integral to combining disparate brain activity into a seamless package of thoughts, sensations and emotions. It takes us a step closer to answering a problem that has confounded scientists and philosophers for millennia – namely how our conscious awareness arises. Many theories abound but most agree that consciousness has to involve the integration of activity from several brain networks, allowing us to perceive our surroundings as one single unifying experience rather than isolated sensory perceptions. One proponent of this idea was Francis Crick, a pioneering neuroscientist who earlier in his career had identified the structure of DNA. Just days before he died in July 2004, Crick was working on a paper that suggested our consciousness needs something akin to an orchestra conductor to bind all of our different external and internal perceptions together. With his colleague Christof Koch, at the Allen Institute for Brain Science in Seattle, he hypothesised that this conductor would need to rapidly integrate information across distinct regions of the brain and bind together information arriving at different times. For example, information about the smell and colour of a rose, its name, and a memory of its relevance, can be bound into one conscious experience of being handed a rose on Valentine's day. © Copyright Reed Business Information Ltd.
Link ID: 19787 - Posted: 07.03.2014
Claire McCarthy I have many patients with ADHD (Attention Deficit Hyperactivity Disorder) and it seems like I have the same conversation over and over again with their parents: to medicate or not to medicate. I completely understand the hesitation I hear from so many parents. I have to admit, I'm not entirely happy myself about prescribing a medication that has side effects and can be abused or misused, and one for which there is a black market. I also worry that too often when a child is on medication and so learning and behaving better, parents and teachers lose the incentive to help the child learn the organizational and other skills that could make all the difference later in life. Since ADHD often persists into adulthood, we have to have the long view with these kids. But....the long view works the other way, too. Not treating ADHD with medication can lead to problems. Like drug abuse. ADHD is really common. It affects 8 percent of children and youth--that's about 2 in every classroom of 20. Kids with ADHD can have real problems with both learning and behavior, problems that can haunt them for a lifetime (if you end up dropping out of high school because of poor grades or behavior, or end up getting arrested, it has a way of interfering with your future income and quality of life). But another thing we know is that kids with ADHD have a higher risk of drug abuse. We don't know exactly why this is the case. Some of it is likely the impulsivity that is so common in people with ADHD; they don't always make the best decisions. It may also be that people with ADHD are more prone to addiction. Whatever it is, the risk is very real. Not only are kids with ADHD 2.5 times more likely to abuse drugs, they are more likely to start earlier, use more types of drugs, and continue into adulthood. ©2014 Boston Globe Media Partners, LLC
By HELENE STAPINSKI A few months ago, my 10-year-old daughter, Paulina, was suffering from a bad headache right before bedtime. She went to lie down and I sat beside her, stroking her head. After a few minutes, she looked up at me and said, “Everything in the room looks really small.” And I suddenly remembered: When I was young, I too would “see things far away,” as I once described it to my mother — as if everything in the room were at the wrong end of a telescope. The episodes could last anywhere from a few minutes to an hour, but they eventually faded as I grew older. I asked Paulina if this was the first time she had experienced such a thing. She shook her head and said it happened every now and then. When I was a little girl, I told her, it would happen to me when I had a fever or was nervous. I told her not to worry and that it would go away on its own. Soon she fell asleep, and I ran straight to my computer. Within minutes, I discovered that there was an actual name for what turns out to be a very rare affliction — Alice in Wonderland Syndrome. Episodes usually include micropsia (objects appear small) or macropsia (objects appear large). Some sufferers perceive their own body parts to be larger or smaller. For me, and Paulina, furniture a few feet away seemed small enough to fit inside a dollhouse. Dr. John Todd, a British psychiatrist, gave the disorder its name in a 1955 paper, noting that the misperceptions resemble Lewis Carroll’s descriptions of what happened to Alice. It’s also known as Todd’s Syndrome. Alice in Wonderland Syndrome is not an optical problem or a hallucination. Instead, it is most likely caused by a change in a portion of the brain, likely the parietal lobe, that processes perceptions of the environment. Some specialists consider it a type of aura, a sensory warning preceding a migraine. And the doctors confirmed that it usually goes away by adulthood. © 2014 The New York Times Company
Nicola Davis The old adage that we eat with our eyes appears to be correct, according to research that suggests diners rate an artistically arranged meal as more tasty – and are prepared to pay more for it. The team at Oxford University tested the idea by gauging the reactions of diners to food presented in different ways. Inspired by Wassily Kandinsky's "Painting Number 201" Franco-Columbian chef and one of the authors of the study, Charles Michel, designed a salad resembling the abstract artwork to explore how the presentation of food affects the dining experience. "A number of chefs now are realising that they are being judged by how their foods photograph – be it in the fancy cookbooks [or], more often than not, when diners instagram their friends," explains Professor Charles Spence, experimental psychologist at the University of Oxford and a co-author of the study. Thirty men and 30 women were each presented with one of three salads containing identical ingredients, arranged either to resemble the Kandinsky painting, a regular tossed salad, or a "neat" formation where each component was spaced away from the others. Seated alone at a table mimicking a restaurant setting, and unaware that other versions of the salad were on offer, each participant was given two questionnaires asking them to rate various aspects of the dish on a 10-point scale, before and after tucking into the salad. Before participants sampled their plateful, the Kandinsky-inspired dish was rated higher for complexity, artistic presentation and general liking. Participants were prepared to pay twice as much for the meal as for either the regular or "neat arrangements". © 2014 Guardian News and Media Limited
By Gary Stix James DiCarlo: We all have this intuitive feel for what object recognition is. It’s the ability to discriminate your face from other faces, a car from other cars, a dog from a camel, that ability we all intuitively feel. But making progress in understanding how our brains are able to accomplish that is a very challenging problem and part of the reason is that it’s challenging to define what it isn’t and is. We take this problem for granted because it seems effortless to us. However, a computer vision person would tell you is that this is an extremely challenging problem because each object presents an essentially infinite number of images to your retina so you essentially never see the same image of each object twice. SA: It seems like object recognition is actually one of the big problems both in neuroscience and in the computational science of machine learning? DiCarlo: That’s right., not only machine learning but also in psychology or cognitive science because the objects that we see are the sources in the world of what we use to build higher cognition, things like memory and decision-making. Should I reach for this, should I avoid it? Our brains can’t do what you would call higher cognition without these foundational elements that we often take for granted. SA: Maybe you can talk about what’s actually happening in the brain during this process. DiCarlo: It’s been known for several decades that there’s a portion of the brain, the temporal lobe down the sides of our head, that, when lost or damaged in humans and non-human primates, leads to deficits of recognition. So we had clues that that’s where these algorithms for object recognition are living. But just saying that part of your brain solves the problem is not really specific. It’s still a very large piece of tissue. Anatomy tells us that there’s a whole network of areas that exist there, and now the tools of neurophysiology and still more advanced tools allow us to go in and look more closely at the neural activity, especially in non-human primates. We can then begin to decipher the actual computations to the level that an engineer might, for instance, in order to emulate what’s going on in our heads. © 2014 Scientific American
by Tania Lombrozo Science doesn't just further technology and help us predict and control our environment. It also changes the way we understand ourselves and our place in the natural world. This understanding can and a sense of . But it can also be , especially when it calls into question our basic assumptions about the kinds of creatures we are and the universe we inhabit. Current developments in neuroscience seem to be triggering precisely this jumble of reactions: wonder alongside disquiet, hope alongside alarm. A recent at Salon.com, for example, promises an explanation for "how neuroscience could save addicts from relapse," while an by Nathan Greenslit at The Atlantic, published less than a week later, raises worries that neuroscience is being used to reinforce racist drug policy. Obama's hails "," but with it comes the need to rapidly work out the of what we're learning about the brain and about ourselves. We're ; but we're not always sure what to make of it. In at the journal Psychological Science, psychologists Azim Shariff, Joshua Greene and six of their colleagues bring these heady issues down to earth by considering whether learning about neuroscience can influence judgments in a real-world situation: deciding how someone who commits a crime should be punished. The motivating intuition is this: to hold someone responsible for her actions, she must have acted with free will. ©2014 NPR
Link ID: 19737 - Posted: 06.17.2014
By MARIA KONNIKOVA THE absurdity of having had to ask for an extension to write this article isn’t lost on me: It is, after all, a piece on time and poverty, or, rather, time poverty — about what happens when we find ourselves working against the clock to finish something. In the case of someone who isn’t otherwise poor, poverty of time is an unpleasant inconvenience. But for someone whose lack of time is just one of many pressing concerns, the effects compound quickly. We make a mistake when we look at poverty as simply a question of financial constraint. Take what happened with my request for an extension. It was granted, and the immediate time pressure was relieved. But even though I met the new deadline (barely), I’m still struggling to dig myself out from the rest of the work that accumulated in the meantime. New deadlines that are about to whoosh by, a growing list of ignored errands, a rent check and insurance payment that I just realized I haven’t mailed. And no sign of that promised light at the end of the tunnel. My experience is the time equivalent of a high-interest loan cycle, except instead of money, I borrow time. But this kind of borrowing comes with an interest rate of its own: By focusing on one immediate deadline, I neglect not only future deadlines but the mundane tasks of daily life that would normally take up next to no time or mental energy. It’s the same type of problem poor people encounter every day, multiple times: The demands of the moment override the demands of the future, making that future harder to reach. When we think of poverty, we tend to think about money in isolation: How much does she earn? Is that above or below the poverty line? But the financial part of the equation may not be the single most important factor. “The biggest mistake we make about scarcity,” Sendhil Mullainathan, an economist at Harvard who is a co-author of the book “Scarcity: Why Having Too Little Means So Much,” tells me, “is we view it as a physical phenomenon. It’s not.” © 2014 The New York Times Company
By Brian Palmer Maureen Dowd, a 62-year-old Pulitzer Prize–winning columnist for the New York Times, had a bad marijuana trip earlier this year. As part of her research into the legalization of recreational cannabis in Colorado, she ate a few too many bites of a pot-infused candy bar, entered a “hallucinatory state,” and spent eight paranoid hours curled up on her hotel room bed. Dowd used the experience as a jumping-off point to discuss the risks of overdosing on edible marijuana, which has become a major issue in pot-friendly states. It’s also possible, however, that Dowd just doesn’t handle cannabis very well. While pot mellows most people out, everyone has heard of someone who barricaded himself or herself in a dorm room after a few bongs hits in college. (Or maybe that someone is you.) Why do people react so differently to the same drug? The question itself may be something of a fallacy. Cannabis is not a single drug—it contains dozens of compounds, and they appear to have varying, and sometimes opposing, effects on the brain. Tetrahydrocannabinol, or THC, and cannabidiol, or CBD, have been the subject of some intriguing research. In 2010, researchers showed that pretreating people with a dose of CBD can protect against the less pleasant effects of THC, such as paranoia. In a similar 2012 study, participants took pills that contained only one of the two chemicals, rather than the combination that you receive in cannabis. The subjects who took THC pills were more likely to suffer paranoia and delusion than those who took CBD. The researchers went one step further to investigate which specific cognitive effects of THC are likely to lead to paranoia and other symptoms of psychosis. After taking either THC or CBD, participants watched a series of arrows appear on a screen and responded by indicating which direction the arrows were pointing. Most of the arrows pointed directly left or right, but occasionally a tilted arrow appeared. (Researchers called the tilted arrows “oddballs.”) Subjects who took the CBD had a heightened brain activity response to the oddballs. That’s the way a nondrugged person typically reacts—repetitions of the same stimulus don’t interest us, but a sudden change grabs our attention. The THC-takers had an abnormal response: They found the left and right arrows, which constituted the overwhelming majority of the images, more noteworthy than the oddballs. © 2014 The Slate Group LLC
—By Indre Viskontas and Chris Mooney We've all been mesmerized by them—those beautiful brain scan images that make us feel like we're on the cutting edge of scientifically decoding how we think. But as soon as one neuroscience study purports to show which brain region lights up when we are enjoying Coca-Cola, or looking at cute puppies, or thinking we have souls, some other expert claims that "it's just a correlation," and you wonder whether researchers will ever get it right. Sam Kean But there's another approach to understanding how our minds work. In his new book, The Tale of the Dueling Neurosurgeons, Sam Kean tells the story of a handful of patients whose unique brains—rendered that way by surgical procedures, rare diseases, and unfortunate, freak accidents—taught us much more than any set of colorful scans. Kean recounts some of their unforgettable stories on the latest episode of the Inquiring Minds podcast. "As I was reading these [case studies] I said, 'That's baloney! There's no way that can possibly be true,'" Kean remembers, referring to one particularly surprising case in which a woman's brain injury left her unable to recognize and distinguish between different kinds of animals. "But then I looked into it, and I realized that, not only is it true, it actually reveals some important things about how the brain works." Here are five patients, from Kean's book, whose stories transformed neuroscience: 1. The man who could not imagine the future: Kent Cochrane (KC), pictured below, was a '70s wild child, playing in a rock band, getting into bar fights, and zooming around Toronto on his motorcycle. But in 1981, a motorcycle accident left him without two critical brain structures. Both of his hippocampi, the parts of the brain that allow us to form new long-term memories for facts and events in our lives, were lost. That's quite different from other amnesiacs, whose damage is either restricted to only one brain hemisphere, or includes large portions of regions outside of the hippocampus. Copyright ©2014 Mother Jones