Chapter 16. None
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by Julia Belluz When neuroscientists stuck a dead salmon in an fMRI machine and watched its brain light up, they knew they had a problem. It wasn't that there was a dead fish in their expensive imaging machine; they'd put it there on purpose, after all. It was that the medical device seemed to be giving these researchers impossible results. Dead fish should not have active brains. The lit of brain of a dead salmon — a cautionary neuroscience tale. (University of California Santa Barbara research poster) The researchers shared their findings in 2009 as a cautionary tale: If you don't run the proper statistical tests on your neuroscience data, you can come up with any number of implausible conclusions — even emotional reactions from a dead fish. In the 1990s, neuroscientists started using the massive, round fMRI (or functional magnetic resonance imaging) machines to peer into their subjects' brains. But since then, the field has suffered from a rash of false positive results and studies that lack enough statistical power — the likelihood of finding a real result when it exists — to deliver insights about the brain. When other scientists try to reproduce the results of original studies, they too often fail. Without better methods, it'll be difficult to develop new treatments for brain disorders and diseases like Alzheimer's and depression — let alone learn anything useful about our most mysterious organ. © 2015 Vox Media, Inc
Keyword: Brain imaging
Link ID: 21292 - Posted: 08.13.2015
Your body may be still, but as you dream, your eyes can flicker manically. The rapid eye movement stage of sleep is when we have our most vivid dreams – but do our flickering eyes actually “see” anything? It is a question psychologists have been asking since REM sleep was first described in the 1950s, says Yuval Nir at Tel Aviv University in Israel. “The idea was that we scan an imaginary scene,” says Nir. “It’s an intuitive idea, but it has been very difficult to provide evidence for it.” Until now, much of the evidence has been anecdotal, says Nir. “People who were woken up when their eyes were moving from left to right would say they were dreaming about tennis, for example,” he says. More evidence comes from a previous study that monitored the sleep of people who have a disorder that means they often physically act out their dreams. Their eye movements matched their actions around 80 per cent of the time – a man dreaming about smoking, for example, appeared to look at a dream ashtray as he put out a cigarette. But most of the REM sleep these people had was not accompanied by body movements, making it hard to know for sure. And other researchers have argued that the eye flickers can’t be linked to “seeing” anything because rapid eye movements happen in both fetuses and people who are blind – neither group would have experience of vision and so wouldn’t be expected to move their eyes to follow an object, for example. © Copyright Reed Business Information Ltd.
Link ID: 21290 - Posted: 08.12.2015
There may finally be a way to stop people progressing beyond the first signs of schizophrenia – fish oil. When people with early-stage symptoms took omega-3 supplements for three months, they had much lower rates of progression than those who did not, according to one small-scale trial. People with schizophrenia are usually diagnosed in their teens or 20s, but may experience symptoms for years beforehand, such as minor delusions or paranoid thoughts. Only about a third of people with such symptoms do go on to develop psychosis, however, and antipsychotic drugs can cause nasty side effects, so these are rarely given as a preventative. Fish oil supplements, which contain polyunsaturated fatty acids like omega-3, may be a benign alternative. These fatty acids may normally help dampen inflammation in the brain and protect neurons from damage, and lower levels in the brain have been implicated in several mental illnesses. Tests have found that people with schizophrenia have lower levels of these fatty acids in their blood cells, suggesting the same could be true for their brain cells. Fish oil supplements have been investigated as a treatment for adults with schizophrenia, but so far results have been mixed – four trials found no benefit while another four found a small reduction in symptoms. But a study that gave omega-3 fish oil pills to younger people suggests that what matters is catching the condition in time. The trial followed 81 people aged 13 to 25 with early signs of schizophrenia. Roughly half took fish oil pills and half took placebo tablets for three months. A year later, those given fish oils were less likely to have developed psychosis. © Copyright Reed Business Information Ltd.
Link ID: 21288 - Posted: 08.12.2015
Despite virtual reality’s recent renaissance, the technology still has some obvious problems. One, you look like a dumbass using it. Two, the stomach-churning mismatch between what you see and what you feel contributes to “virtual reality sickness.” But there’s another, less obvious flaw that could add to that off-kilter sensation: an eye-focusing problem called vergence-accommodation conflict. It’s only less obvious because, well, you rarely experience it outside of virtual reality. At SIGGRAPH in Los Angeles this week, Stanford professor Gordon Wetzstein and his colleagues are presenting a new head-mounted display that minimizes the vergence-accommodation conflict. This isn’t just some esoteric academic problem. Leading VR companies like Oculus and Microsoft know all too well their headsets are off, and Magic Leap, the super secret augmented reality company in Florida, is betting the house on finding a solution first. “It’s an exciting area of research,” says Martin Banks, a vision scientist at the University of California, Berkeley. “I think it’s going to be the next big thing in displays.” Okay okay, so what’s the big deal with the vergence-accommodation conflict? Two things happen when you simply “look” at an object. First, you point your eyeballs. If an object is close, your eyes naturally converge on it; if it’s far, they diverge. Hence, vergence. If your eyes don’t line up correctly, you end up seeing double. The second thing that happens is the lenses inside your eyes focus on the object, aka accommodation. Normally, vergence and accommodation are coupled. “The visual system has developed a circuit where the two response talk to each other,” says Banks. “That makes perfect sense in the natural environment. They’re both trying to get to the same distance, so why wouldn’t they talk to one another?” In other words, your meat brain has figured out a handy shortcut for the real world.
Link ID: 21287 - Posted: 08.12.2015
By Dina Fine Maron Don’t stress too much about cutting calories if you want to shed pounds—focus on getting more exercise. That’s the controversial message beverage giant Coca-Cola is backing in its new campaign to curb obesity. Coke is pushing this idea via a new Coke-backed nonprofit called Global Energy Balance Network, The New York Times reported on August 9. Money from Coke, the Times reported, is also financing studies that support the notion that exercise trumps diet. But is there any merit to such a stance? Not much, says Rutgers University–based diet and behavior expert Charlotte Markey. She is the author of an upcoming cover story in Scientific American MIND on this topic, and spoke about the Coke claims with Scientific American on Monday. In your fall Scientific American MIND feature you write “study after study shows that working out is not terribly effective for weight loss on its own.” Why is that? Exercise increases appetite, and most people just make up for whatever they exercised off. There’s a lot of wonderful reasons to exercise and I always suggest it to people who are trying to lose weight—some sort of exercise regimen keeps them focused on their health and doing what is good for them, and it’s psychologically healthy. But in and of itself it won’t usually help people lose weight. Two years ago there was a review study in Frontiers in Psychology that concluded dieting often actually led to weight gain. Why would that happen? When people try to diet, they try to restrict themselves, which often leads to overeating. They cut out food groups which make those food groups more desirable to them. They think too much about short-term goals and don’t think about sustainable changes. But if you are going to lose weight, you have to change your behaviors for the rest of your life or otherwise you gain it back. That’s not a sexy message because it seems daunting. © 2015 Scientific American
Link ID: 21285 - Posted: 08.12.2015
Sarah Schwartz In 2011, science journalist Jon Palfreman saw a doctor about a tremor in his left hand. The doctor diagnosed Palfreman, then 60, with Parkinson’s disease. The disorder, which is newly diagnosed in 60,000 Americans each year, promised a crippling future of tremors, loss of mobility, dementia and more. Palfreman decided to use his reporting expertise to investigate how Parkinson’s disease affects the body and learn about efforts to find a cure. With Brain Storms, Palfreman follows Parkinson’s history from the careful observations of 19th century physicians to today’s cutting-edge research. Palfreman relates complex research studies as gripping medical mysteries. He describes how scientists connected Parkinson’s with the dramatic loss of the brain chemical dopamine and with tenacious protein knots called Lewy bodies that are a hallmark of the disease. Palfreman also explores treatments past and present, including the widely used drug levodopa that restores motion (sometimes uncontrollably), gene therapies, brain surgeries and promising experimental antibody treatments that attack and dissolve misfolded Parkinson’s-related proteins. Ultimately, Brain Storms is about more than Parkinson’s disease; it’s about the people living with the disorder. Palfreman describes patients who must teach themselves to walk without falling over or who freeze in place. He writes about a researcher driven to search for a cure after the disease affects his own father. © Society for Science & the Public 2000 - 2015
Link ID: 21284 - Posted: 08.12.2015
By Anahad O’Connor Coca-Cola, the world’s largest producer of sugary beverages, is backing a new “science-based” solution to the obesity crisis: To maintain a healthy weight, get more exercise and worry less about cutting calories. The beverage giant has teamed up with influential scientists who are advancing this message in medical journals, at conferences and through social media. To help the scientists get the word out, Coke has provided financial and logistical support to a new nonprofit organization called the Global Energy Balance Network, which promotes the argument that weight-conscious Americans are overly fixated on how much they eat and drink while not paying enough attention to exercise. “Most of the focus in the popular media and in the scientific press is, ‘Oh they’re eating too much, eating too much, eating too much’ — blaming fast food, blaming sugary drinks and so on,” the group’s vice president, Steven N. Blair, an exercise scientist, says in a recent video announcing the new organization. “And there’s really virtually no compelling evidence that that, in fact, is the cause.” Health experts say this message is misleading and part of an effort by Coke to deflect criticism about the role sugary drinks have played in the spread of obesity and Type 2 diabetes. They contend that the company is using the new group to convince the public that physical activity can offset a bad diet despite evidence that exercise has only minimal impact on weight compared with what people consume. This clash over the science of obesity comes in a period of rising efforts to tax sugary drinks, remove them from schools and stop companies from marketing them to children. In the last two decades, consumption of full-calorie sodas by the average American has dropped by 25 percent. © 2015 The New York Times Company
Link ID: 21283 - Posted: 08.10.2015
Rachel Martin The National Football League held its annual hall of fame induction ceremony Saturday night, in Canton, Ohio. Eight players were given football's highest honor, including a posthumous induction for Junior Seau, the former linebacker for the San Diego Chargers who killed himself in 2012. After his death, Seau's brain showed signs of chronic damage — the same kind of damage that has been found in dozens of other former NFL players. Scientific studies have shown that the kind of repeated hits NFL players take is linked to chronic traumatic encephalopathy, or CTE, a degenerative brain disease. CTE is associated with memory loss, impulse control problems, depression and eventually dementia. Some players are rethinking their careers — like up-and-coming linebacker Chris Borland, who quit after his first season with the 49ers a few months ago — for fear of head injuries. Parents are weighing the risks as well. So when someone like Chicago Bears coach Mike Ditka talks, they listen. When host Bryant Gumbel asked Ditka on HBO's Real Sports earlier this year whether, if he had an 8-year-old now, he would want him to play football. "No," he answered. "That's sad. I wouldn't, and my whole life was football. I think the risk is worse than the reward." Tregg Duerson's father, Dave Duerson, a defensive back who played most of his pro football career with the Chicago Bears, killed himself in 2011 in his Miami home. Duerson was part of the legendary '85 team that won the Superbowl, and five years later helped the New York Giants win their own championship. © 2015 NPR
Keyword: Brain Injury/Concussion
Link ID: 21281 - Posted: 08.10.2015
By John Danaher Discoveries in neuroscience, and the science of behaviour more generally, pose a challenge to the existence of free will. But this all depends on what is meant by ‘free will’. The term means different things to different people. Philosophers focus on two conditions that seem to be necessary for free will: (i) the alternativism condition, according to which having free will requires the ability to do otherwise; and (ii) the sourcehood condition, according to which having free will requires that you (your ‘self’) be the source of your actions. A scientific and deterministic worldview is often said to threaten the first condition. Does it also threaten the second? That is what Christian List and Peter Menzies article “My brain made me do it: The exclusion argument against free will and what’s wrong with it” tries to figure out. As you might guess from the title, the authors think that the scientific worldview, in particular the advances in neuroscience, do not necessarily threaten the sourcehood condition. I discussed their main argument in the previous post. To briefly recap, they critiqued an argument from physicalism against free will. According to this argument, the mental states which constitute the self do not cause our behaviour because they are epiphenomenal: they supervene on the physical brain states that do all the causal work. List and Menzies disputed this by appealing to a difference-making account of causation. This allowed for the possibility of mental states causing behaviour (being the ‘difference makers’) even if they were supervenient upon underlying physical states.
Link ID: 21279 - Posted: 08.10.2015
Nell Greenfieldboyce Take a close look at a house cat's eyes and you'll see pupils that look like vertical slits. But a tiger has round pupils — like humans do. And the eyes of other animals, like goats and horses, have slits that are horizontal. Scientists have now done the first comprehensive study of these three kinds of pupils. The shape of the animal's pupil, it turns out, is closely related to the animal's size and whether it's a predator or prey. The pupil is the hole that lets light in, and it comes in lots of different shapes. "There are some weird ones out there," says Martin Banks, a vision scientist at the University of California, Berkeley. Cuttlefish have pupils that look like the letter "W," and dolphins have pupils shaped like crescents. Some frogs have heart-shaped pupils, while geckos have pupils that look like pinholes arranged in a vertical line. Needless to say, scientists want to know why all these different shapes evolved. "It's been an active point of debate for quite some time," says Banks, "because it's something you obviously observe. It's the first thing you see about an animal — where their eye is located and what the pupil shape is." For their recent study, Banks and his colleagues decided to keep things simple. They looked at just land animals, and just three kinds of pupils. "We restricted ourselves to just pupils that are elongated or not," Banks explains. "So they're either vertical, horizontal or round." © 2015 NPR
By John Danaher Consider the following passage from Ian McEwan’s novel Atonement. It concerns one of the novel’s characters (Briony) as she philosophically reflects on the mystery of human action: She raised one hand and flexed its fingers and wondered, as she had sometimes done before, how this thing, this machine for gripping, this fleshy spider on the end of her arm, came to be hers, entirely at her command. Or did it have some little life of its own? She bent her finger and straightened it. The mystery was in the instant before it moved, the dividing moment between not moving and moving, when her intention took effect. It was like a wave breaking. If she could only find herself at the crest, she thought, she might find the secret of herself, that part of her that was really in charge. Is Briony’s quest forlorn? Will she ever find herself at the crest of the wave? The contemporary scientific understanding of human action seems to cast this into some doubt. A variety of studies in the neuroscience of action paint an increasingly mechanistic and subconscious picture of human behaviour. According to these studies, our behaviour is not the product of our intentions or desires or anything like that. It is the product of our neural networks and systems, a complex soup of electrochemical interactions, oftentimes operating beneath our conscious awareness. In other words, our brains control our actions; our selves (in the philosophically important sense of the word ‘self’) do not. This discovery — that our brains ‘make us do it’ and that ‘we’ don’t — is thought to have a number of significant social implications, particularly for our practices of blame and punishment.
Link ID: 21276 - Posted: 08.08.2015
By SAM ROBERTS Dr. Louis Sokoloff, who pioneered the PET scan technique for measuring human brain function and diagnosing disorders, died on July 30 in Washington. He was 93. His death was confirmed by his daughter, Ann, his only immediate survivor. Dr. Sokoloff, who headed the brain metabolism laboratory at the National Institute of Mental Health in Bethesda, Md., received the Albert Lasker Clinical Medical Research Award in 1981 for his role in developing the vivid color images that map brain function. The technique measures the metabolism of its primary fuel, glucose, through a radioactive substitute that, unlike glucose, lingers long enough to undergo chemical analysis. “The Sokoloff method,” the Lasker Foundation said, “has facilitated the diagnosis, understanding and possible future treatment of such disorders of the brain as schizophrenia, epilepsy, brain changes due to drug addiction and senile dementia.” As early as the mid-1940s, when he was practicing psychotherapy in the Army as chief of neuropsychiatry at Camp Lee, Va. (now Fort Lee), he believed there was a physiological and biochemical component to mental illness. “Of course, the psychoanalysts said it had nothing to do with the brain; it had to do with the mind — it could have been anywhere, it could have been in the big toe,” he said in an interview in 2005, shortly after he officially retired from the institute. “For me, mind and brain were inextricably linked,” he wrote in an autobiographical essay published in 1996, “a linkage that was irrelevant to psychiatry at that time.” © 2015 The New York Times Company
Keyword: Brain imaging
Link ID: 21273 - Posted: 08.08.2015
By Rachel Feltman Ever wondered what the world looks like to nonhuman animals? Scientists do, too. It can actually be a really important question. Sometimes humans can't see things -- like skin markings designed to attract mates or flower colors meant to draw pollinators -- that are incredibly important in the life and behavior of an animal. That's why researchers at the University of Exeter have developed a software that converts photos to "animal vision." The software, which is available for free online, is described in a recent paper in the journal Methods in Ecology and Evolution. Its creators have already used it extensively themselves to perform studies on animals who see light outside the spectrum visible to humans. They've also used it to track imperceptible color changes that occur in women's faces during ovulation. The software works by integrating photos taken using ultraviolet filters with those taken using regular color filters, a process that scientists used to have to dial in manually for whatever species they were studying. By meshing the visible light spectrum with information from a full-spectrum image, the software can replicate the visual experience of animals who see more colors than humans, including light in the ultraviolet range.
Link ID: 21272 - Posted: 08.08.2015
Tina Hesman Saey Memory Transfer Seen — Experiments with rats, showing how chemicals from one rat brain influence the memory of an untrained animal, indicate that tinkering with the brain of humans is also possible. In the rat tests, brain material from an animal trained to go for food either at a light flash or at a sound signal was injected into an untrained rat. The injected animals then "remembered" whether light or sound meant food. — Science News Letter, August 21, 1965 Update: After this report, scientists from eight labs attempted to repeat the memory transplants. They failed, as they reported in Science in 1966. Science fiction authors and futurists often predict that a person’s memories might be transferred to another person or a computer, but the idea is likely to remain speculation, says neuroscientist Eric Kandel, who won a Nobel Prize in 2000 for his work on memory. Brain wiring is too intricate and complicated to be exactly replicated, and scientists are still learning about how memories are made, stored and retrieved. W. L. Byrne et al. Technical Comments: Memory Transfer. Science Vol. 153, August 5, 1966, p. 658. doi:10.1126/science.153.3736.658 © Society for Science & the Public 2000 - 2015
Keyword: Learning & Memory
Link ID: 21271 - Posted: 08.08.2015
By Mitch Leslie If you need to lose a lot of weight, surgeons have a drastic option: They can reroute and sometimes remove parts of your stomach, making it smaller. But instead of limiting the amount of food you can eat, the surgery may work by triggering long-term changes in the types of microbes that inhabit your intestines, a new study suggests. If so, altering the kinds of microbes that live in your gut may be a simpler—and safer—route to weight loss. The research provides “some of the best evidence in humans so far” that bariatric surgery works “in part by changing the bacteria in your gut,” says David Cummings, an endocrinologist at the University of Washington, Seattle, who was not involved with the work. Weight loss isn’t the only benefit of so-called bariatric surgery. If a patient has diabetes, for instance, it will usually disappear. The surgery alters metabolism and digestive system functions in several ways, and researchers are still trying to pin down why it’s effective. “This is not about making your stomach small,” says Randy Seeley, an obesity and diabetes researcher at the University of Michigan, Ann Arbor, who wasn’t connected to the study. One way that bariatric surgery might trigger its effects is through its influence on the microbiota, the swarms of microbes that dwell in our intestines and help us digest food. Studies have found that bariatric surgery dramatically alters the microbiota’s makeup in mice and humans. Two years ago, scientists put mice through a Roux-en-Y gastric bypass—a type of bariatric surgery that involves reducing the stomach to a small pouch and stitching it to the middle part of the small intestine—and then transplanted microbes from the slimmed down animals into mice that lacked intestinal bacteria. The recipient rodents lost 5% of their body weight in 2 weeks. But these studies only checked for short-term changes. © 2015 American Association for the Advancement of Science
Link ID: 21269 - Posted: 08.05.2015
By Julie Scelfo This week, I wrote about the pressures college students face and the related risk for depression and suicide. The article, “Suicide on Campus and the Pressure for Perfection,” generated numerous comments, and readers also raised important questions about other aspects of mental health. Q.Your story seemed to focus on women. Do boys and men experience the same kinds of pressure? A.Yes, male college students experience the same kind of pressure and commit suicide at significantly higher rates than their female counterparts. The rate of suicide among 15 to 24-year-old males in the United States was 17.3 per 100,000 in 2013, compared with 4.5 among females of the same age, according to the Centers for Disease Control and Prevention. In fact, men of all ages are far more likely to commit suicide than women. Q.If men are more likely to commit suicide, why did the story focus on a female student? A. There is still tremendous stigma surrounding mental illness, and not everyone who experiences depression is willing to talk about it. The young woman I profiled, Kathryn DeWitt, offered a rare opportunity to hear from someone who had gone all the way down to the depths of despair but — thankfully — was still alive to talk about it (and could do so articulately). Male depression is a significant concern, and a topic I have written about in the past. More information and resources are available from The National Alliance on Mental Illness. Q.Why didn’t you talk about high rates of suicide among Asian-American students? A.While suicide among Asian-American students is a significant concern, data from the C.D.C. shows the racial/ethnic group with the highest suicide rate is actually American-Indian/Alaskan Native. According to the C.D.C, the rate of suicide in that group for 15 to 24-year-olds is 9.4 for females and a staggering 29.1 for males. Q.Are parents to blame for suicide? A. The cause of any individual suicide is complex, and it would be a mistake to assume parents are to blame if a child attempts suicide. Gregory Eels, the director of Counseling and Psychological Services at Cornell, who has worked in higher education for 20 years and says he has seen “too many” student deaths, describes it this way: “The causes of a completed suicide are never a single thing. It’s a combination of thousands of things.” © 2015 The New York Times Company
Link ID: 21266 - Posted: 08.05.2015
// by Richard Farrell Bonobos have a capacity to do something human infants have been shown to do: use a single sound whose meaning varies based on context, a form of "flexible" communication previously thought specific to humans. The finding was made by researchers from the University of Birmingham and the University of Neuchatel, in a paper just published in the journal Peer J. The newly identified bonobo call is a short, high-pitched "peep," made with a closed mouth. The scientists studied the call's acoustic structure and observed that it did not change between what they termed "neutral" and "positive" circumstances (for example, between activities such as feeding or resting), suggesting that other bonobos receiving the call would need to weigh contextual information to discern its meaning. Human babies do something similarly flexible, using sounds called protophones -- different from highly specific sounds such as crying or laughter -- that are made independent of how they are feeling emotionally. The appearance of this capability in the first year of life is "a critical step in the development of vocal language and may have been a critical step in the evolution of human language," an earlier study on infant vocalization noted. The find challenges the idea that calls from primates such as bonobos -- which, along with chimpanzees, are our closest relatives -- are strictly matched with specific contexts and emotions, whether those sounds are territorial barks or shrieks of alarm. © 2015 Discovery Communications, LLC.
By Michael Balter Have you ever wondered why you say “The boy is playing Frisbee with his dog” instead of “The boy dog his is Frisbee playing with”? You may be trying to give your brain a break, according to a new study. An analysis of 37 widely varying tongues finds that, despite the apparent great differences among them, they share what might be a universal feature of human language: All of them have evolved to make communication as efficient as possible. Earth is a veritable Tower of Babel: Up to 7000 languages are still spoken across the globe, belonging to roughly 150 language families. And they vary widely in the way they put sentences together. For example, the three major building blocks of a sentence, subject (S), verb (V), and object (O), can come in three different orders. English and French are SVO languages, whereas German and Japanese are SOV languages; a much smaller number, such as Arabic and Hebrew, use the VSO order. (No well-documented languages start sentences or clauses with the object, although some linguists have jokingly suggested that Klingon might do so.) Yet despite these different ways of structuring sentences, previous studies of a limited number of languages have shown that they tend to limit the distance between words that depend on each other for their meaning. Such “dependency” is key if sentences are to make sense. For example, in the sentence “Jane threw out the trash,” the word “Jane” is dependent on “threw”—it modifies the verb by telling us who was doing the throwing, just as we need “trash” to know what was thrown, and “out” to know where the trash went. Although “threw” and “trash” are three words away from each other, we can still understand the sentence easily. © 2015 American Association for the Advancement of Science.
By Roni Caryn Rabin For years experts have urged physicians to screen infants and toddlers for autism in order to begin treatment as early as possible. But now an influential panel of experts has concluded there is not enough evidence to recommend universal autism screening of young children. The findings, from a draft proposal by the U.S. Preventive Services Task Force published Monday, are already causing consternation among specialists who work with autistic children. “I was in a meeting when I read this, and I started feeling like I’d have chest pain,” said Dr. Susan E. Levy, a pediatrician who helped write the American Academy of Pediatrics guidelines urging universal screening of all babies, with standardized screening tools at both 18 and 24 months. “I would hate to see people stop screening.” Dr. David Grossman, a pediatrician and vice chairman of the U.S. Preventive Services Task Force, emphasized that the panel’s draft proposal was a call for more research and not intended to change practices. About half of all pediatricians routinely screen toddlers for autism. “This doesn’t mean ‘don’t screen.’ ” Dr. Grossman said. “It means there is not enough evidence to make a recommendation.” Dr. Grossman also noted that the panel’s conclusion applied only to routine screening of healthy children without symptoms. A child displaying symptoms associated with autism should always be evaluated, he said. “If a parent comes in and says, ‘My child isn’t looking at me,’ that’s not a screening,” Dr. Grossman said. “You hear that as a doctor and you say, ‘That needs to be looked at,’ and you embark on a series of tests.” Despite those reassurances, autism experts worry that the panel’s lack of support for early autism screening could undermine efforts to identify and treat children as early as possible. The task force is an independent panel of experts in prevention and primary care appointed by the federal Department of Health and Human Services. The task force wields enormous influence in the medical community. In 2009, the panel issued controversial screening guidelines for breast cancer, stating that routine mammograms should start at 50 rather than 40. © 2015 The New York Times Company
Link ID: 21262 - Posted: 08.04.2015
By Andrea Alfano Forget the insult “fathead.” We may actually owe our extraordinary smarts to the fat in our brain. A study published in Neuron in February revealed that the variety of fat molecules found in the human neocortex, the brain region responsible for advanced cognitive functions such as language, evolved at an exceptionally fast rate after the human-ape split. The researchers analyzed the concentrations of 5,713 different lipids, or fat molecules and their derivatives, present in samples of brain, kidney and muscle tissues taken from humans, chimpanzees, macaques and mice. Lipids have a variety of critical functions in all cells, including their role as the primary component of a cell's membrane. They are particularly important in the brain because they enable electrical signal transmission among neurons. Yet until this study, it was unknown whether the lipids in the human brain differed significantly from lipids in other mammals. The team discovered that the levels of various lipids found in human brain samples, especially from the neocortex, stood out. Humans and chimps diverged from their common ancestor around the same time, according to much evolutionary evidence. Because the two species have had about the same amount of time to rack up changes to their lipid profiles, the investigators expected them to have roughly the same number of species-specific lipid concentrations, explains computational biologist and study leader Kasia Bozek of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. Indeed, lipid changes in the cerebellum, a primitive part of the brain similar in all vertebrates, were comparable between humans and chimps. But the human neocortex has accumulated about three times more lipid changes than the chimpanzee cortex has since we split from our common ancestor. © 2015 Scientific American
Link ID: 21260 - Posted: 08.04.2015