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By Anahad O'Connor For much of his life, Dr. Vincent Pedre, an internist in New York City, suffered from digestive problems that left him feeling weak and sick to his stomach. As an adult he learned he had irritable bowel syndrome, or I.B.S., a chronic gut disorder that affects up to 10 percent of Americans. Through the process of elimination, Dr. Pedre discovered that his diet was the source of many of his problems. Cutting out dairy and gluten reversed many of his symptoms. Replacing processed foods with organic meats, fresh vegetables and fermented foods gave him more energy and settled his sensitive stomach. Dr. Pedre, a clinical instructor in medicine at the Mount Sinai School of Medicine, began to encourage many of his patients who were struggling with digestive disorders to do the same, helping them to identify food allergens and food sensitivities that could act as triggers. He also urged his patients to try yoga and meditation to alleviate chronic stress, which can worsen digestive problems. Dr. Pedre now has a medical practice specializing in gastrointestinal disorders and is the author of a new book called “Happy Gut.” In the book, Dr. Pedre argues that chronic health problems can in some cases be traced to a dysfunctional digestive system, which can be quelled through a variety of lifestyle behaviors that nurture the microbiota, the internal garden of microbes that resides in the gut. Recently, we caught up with Dr. Pedre to talk about what makes a “happy gut,” how you can avoid some common triggers of digestive problems, and why fermented foods like kombucha and kimchi should be part of your diet. Here are edited excerpts from our conversation. © 2016 The New York Times Company
Link ID: 21788 - Posted: 01.14.2016
By Katherine Harmon Here’s another reason to eat your vegetables. Trillions of microbes in the human large intestine—known as the microbiome—depend on dietary fiber to thrive and give us energy. As fiber intake declines, so, too, does the range of bacteria that can survive in the gut. Now, a new study of multiple generations of mice fed a low-fiber diet indicates that this diversity plummets further with each generation, a hint of what might be happening in the human gut as we continue eating a contemporary diet of refined foods. The work might also help explain rises in many Western diseases, such as inflammatory bowel disease and obesity. "This is a seminal study," says microbial ecologist Jens Walter, of the University of Alberta in Canada. "The magnitude by which the low-[fiber] diet depletes the microbiome in the mouse experiments is startling." For much of human history in hunter-gatherer and early agrarian times, daily fiber intake was likely at least three or four times the officially recommended amounts today (something like 100 grams versus 25 grams)—and several times greater than average U.S. consumption now (about 15 grams). The trend has led many researchers, including microbiologist Erica Sonnenburg of Stanford University in Palo Alto, California, to suspect that the well-documented low diversity of gut microbes among people in developed countries—some 30% less diverse than in modern hunter-gatherers—is, in part, a product of drastically reduced fiber intake. © 2016 American Association for the Advancement of Science. A
Link ID: 21787 - Posted: 01.14.2016
David Cox In the spring of 1930, Danish artist Einar Wegener arrived in Berlin for a consultation that he hoped would both save and change his life. Wegener had spent the previous twenty years dressing as a woman, Lili Elbe. In public, his wife, painter Gerda Gottlieb, introduced Elbe as Wegener’s sister . But by 1930 he could not bear his double life any longer. He resolved to commit suicide, even naming a date – May 1. Instead, Wegener made a different choice, electing to undergo a series of pioneering gender reassignment operations, transitioning into Lili Ilse Elvenes, better known as Lili Elbe. Elbe’s extraordinary story remains controversial; indeed, the film The Danish Girl, starring Eddie Redmayne and based on Elbe’s life was this week banned from Qatari cinemas after protests about its “depravity”. Elbe’s revolutionary transition would not have been possible without the contribution of the sexologist Magnus Hirschfeld, a man who had become both renowned and notorious across Europe for his groundbreaking research into human gender and sexuality. While Elbe’s posthumous 1933 biography, “Man into Woman: The First Sex Change”, made her story internationally famous, Hirschfeld is a less well-known figure today. As both a Jew and gay activist, much of his legacy was burnt to ashes when his Institute for Sexual Research was targeted by a Nazi attack in 1933. But through colleagues and pupils, his work has gone on to transform the way we view sexual minorities and has helped make gender reassignment surgery the widely accepted procedure it is today. © 2016 Guardian News and Media Limited o
Keyword: Sexual Behavior
Link ID: 21786 - Posted: 01.14.2016
Eva Emerson Chronic stress takes its toll on everyone. But it may hit women harder (or at least differently) than men, much research finds. New studies in rodents show that females remain sensitive to ongoing stress longer than males do, as Susan Gaidos reports. It remains to be seen whether such results can explain the differences in rates of depression and anxiety disorders in men and women. (Perhaps women are more likely to discuss their symptoms and be diagnosed. Men, on the other hand, are more likely to abuse drugs and alcohol, disorders which may also be related to stress.) Still, the new work offers an intriguing idea: If stress induces distinct biochemical signaling in men and women, perhaps therapies should also be tailored to each sex. Another fascinating line of research mentioned in Gaidos’ story involves altering female mice’s response to chronic stress (making it more like a male’s) by targeting DNA modifications known as epigenetic tags. Consisting of chemicals such as methyl groups, these tags are attached to DNA and influence gene activity. They seem like a perfect target for drugs. Epigenetic tags don’t change the underlying genes, just the instructions for turning those genes on or off, up or down. In the mice, scientists used enzymes to alter the chemical tags on genes involved in the response to chronic stress. It’s an exciting approach, one I’m sure many scientists will try in efforts to modulate the body’s response, not just to stress, but also to other threats to health. Maybe even to fat. A woman’s extra fat can trigger metabolic changes in a developing fetus, Laura Beil reports. Beil describes the latest research about the risks faced by children of obese moms or moms who have gained too much weight while pregnant. Neurological effects are the new twist, and a scary one, given the prevalence of obesity among women of childbearing age. © Society for Science & the Public 2000 - 2015
Maggie Koerth-Baker In 1990, when James Danckert was 18, his older brother Paul crashed his car into a tree. He was pulled from the wreckage with multiple injuries, including head trauma. The recovery proved difficult. Paul had been a drummer, but even after a broken wrist had healed, drumming no longer made him happy. Over and over, Danckert remembers, Paul complained bitterly that he was just — bored. “There was no hint of apathy about it at all,” says Danckert. “It was deeply frustrating and unsatisfying for him to be deeply bored by things he used to love.” A few years later, when Danckert was training to become a clinical neuropsychologist, he found himself working with about 20 young men who had also suffered traumatic brain injury. Thinking of his brother, he asked them whether they, too, got bored more easily than they had before. “And every single one of them,” he says, “said yes.” Those experiences helped to launch Danckert on his current research path. Now a cognitive neuroscientist at the University of Waterloo in Canada, he is one of a small but growing number of investigators engaged in a serious scientific study of boredom. There is no universally accepted definition of boredom. But whatever it is, researchers argue, it is not simply another name for depression or apathy. It seems to be a specific mental state that people find unpleasant — a lack of stimulation that leaves them craving relief, with a host of behavioural, medical and social consequences. © 2016 Nature Publishing Group
By SABRINA TAVERNISE SILVER SPRING, Md. — A panel of medical experts recommended Tuesday that the Food and Drug Administration approve a new way of treating opioid addicts, using a slender rod implanted into the arm that delivers medicine for months at a time. Some doctors say it could help ease the national epidemic of drug overdoses. The rod is about the size of a small matchstick and delivers daily doses of buprenorphine — one of the most common medical treatments for opioid addicts — for six-month periods. In controlled doses, buprenorphine can help the body withdraw from opioid addiction, but can also itself be addictive. That risk is increased by the fact that the medicine can be taken only by mouth, requiring patients, often ill from addiction, to manage their daily dosages. The advisory panel voted 12 to 5 to recommend approval. The panel concluded that flaws in the evidence the company presented, including missing data in a clinical study, were not fatal, and that the product was roughly as effective as the oral form of the drug. They agreed it would be a useful tool for doctors in the face of a major public health epidemic and could help stem the flow of illicit use of buprenorphine. “I think this will save some folks’ lives,” said Dr. David Pickar, adjunct professor of psychiatry at Johns Hopkins Medical School, who voted to recommend approval. “From a safety point of view I think we’re in good shape.” Dr. Thomas Grieger, a staff psychiatrist at the Maryland Department of Health and Mental Hygiene, said: “There is not evidence of significant risk using this agent, but there is evidence of significant benefit.” © 2016 The New York Times Company
Keyword: Drug Abuse
Link ID: 21783 - Posted: 01.13.2016
By Virginia Morell When you hear a bird warbling, you probably think the crooner is a male. And chances are if you’re in the Northern Hemisphere, you would be right. But females also evolved to sing, and many still do—although generally less than the males. One reason may be that it’s more dangerous for them to sing especially when nesting, scientists report today. At least, that’s the case for female fairywrens, the most vocal of which are the most likely to have their eggs and chicks eaten. The study “provides some of the first field evidence indicating why females of so many songbird species might have lost song,” says Karan Odom, a Ph.D. candidate at the University of Maryland, Baltimore, and the lead author of a 2014 study on the evolution of birdsong. Female superb fairywrens (Malarus cyaneus)—a small Australian species—aren’t the only female songbirds that sing. In fact, females sing in 71% of songbird species, often for territorial defense. In species like the superb fairywren, some females even sing when they’re on their nests, a place where, at least theoretically, they should pipe down so as not to attract predators. Rodents, birds, cats, and foxes have all been seen preying on the fairywrens’ nests. “People had observed [this singing in the nest behavior], but they hadn’t investigated it,” says Sonia Kleindorfer, a behavioral ecologist at Flinders University in Adelaide, Australia. “It struck me as odd, and very risky.” © 2016 American Association for the Advancement of Science
Laura Beil When Elinor Sullivan was a postdoctoral fellow at Oregon Health & Science University in Portland, she set out to explore the influence of food and exercise habits on obesity. In one experiment, she and her colleagues fed a troop of macaque monkeys regular chow. Other macaques dined American-style, with a hefty 32 percent of calories from fat and ready access to peanut butter treats. Over time, the second group of monkeys grew noticeably fatter. Then they all had babies. Sullivan, now at the University of Portland, noticed odd behavior in the plump moms’ offspring. At playtime, they often slinked off by themselves. When handled by keepers, the infants tended to vocalize anxiously, and the males became aggressive. They were prone to repetitive habits, like pacing. In their carefully controlled world, the only difference between those monkeys and others at the facility was their mothers’ extra pounds and indulgent diet. The behavior was so striking that Sullivan changed the course of her research. “It made me start thinking about human children,” she says, and the twin epidemics of obesity and behavioral problems such as attention-deficit/hyperactivity disorder. Her research, published in 2010 in the Journal of Neuroscience, was one of the first studies to note that the progeny of female monkeys eating a high-fat diet were more likely to experience altered brain development and suffer anxiety. Not long after, researchers worldwide began compiling evidence linking the heaviness of human mothers to mental health in their children. One headline-grabbing study of more than 1,000 births, reported in 2012, found that autism spectrum disorders showed up more often in children of obese mothers than in normal-weight women (SN: 5/19/12, p. 16). © Society for Science & the Public 2000 - 2015.
By Gretchen Reynolds. To handle stress and adversity more effectively, we should probably pay closer attention to what is happening inside our bodies, according to a fascinating new brain study of resilience and why some people seem to have more of it than others. We live in difficult times, as readers of this newspaper know well. Worries about the state of our world, our safety, our finances, health and more can lead to a variety of physiological and psychological responses. “When faced with stress, whether it’s giving a talk in front of a hundred people or feeling pressured to get a second gold medal at the Olympics, we experience changes in our body,” said Lori Haase, a clinical professor of psychiatry at the University of California in San Diego and lead author of the new study. Our heart rates rise, breathing grows shallow, and blood levels of adrenaline and other stress chemicals soar. While this stress response can have desirable results — “I need anxiety to motivate myself to write a grant,” Dr. Haase said — it can easily can get out of hand. Remaining in a state of heightened arousal undermines physical and mental performance, she explained. So while our bodies should respond to dangers and worries, our stress reactions also should dissipate as soon as possible afterward. This is where resilience comes in. In scientific terms, resilience is the ability to rapidly return to normal, both physically and emotionally, after a stressful event. Scientists and therapists long have known that some people are more resilient than others but had not known precisely why. © 2016 The New York Times Company
Link ID: 21780 - Posted: 01.13.2016
By Virginia Morell Dog owners often say they “know” that their dog understands what they’re feeling. Now, scientists have the evidence to back this up. Researchers tested 17 adult dogs of various breeds to see whether they could recognize emotional expressions in the faces and voices of humans and other dogs—an ability that’s considered a higher cognitive talent because two different senses are involved. Each dog took part in two test sessions with 10 trials. One by one, they stood facing two screens on which the researchers projected photos of unfamiliar but happy/playful human or dog faces versus the same faces with angry/aggressive expressions (as in the photo above). At the same time, the scientists played a single vocalization—either a dog bark, or an unfamiliar human speaking in Portuguese, a language none of the dogs had previously heard, or a neutral sound. The dogs looked much longer at a face (dog or human) when the expression matched the tone of the voice, a measure that’s also been used to assess various cognitive abilities of other mammals, the scientists report online today in Biology Letters. The dogs were best at this when looking at a fellow dog, which supports another study showing that dogs preferred looking at images of other dogs rather than those of humans. It’s the first time that a species, other than humans, has been shown to be capable of interpreting the vocal and facial expressions of an entirely different species of animal—a talent that surely helps Fido survive in its ecological niche: the jungle of the human home. © 2016 American Association for the Advancement of Science.
Link ID: 21779 - Posted: 01.13.2016
Susan Gaidos Muscles tighten, the heart pounds and nausea takes hold: In the face of sudden stress, men and women respond alike. But when threats, scares or frustrations continue for days or months, differences between the sexes emerge. Scientists have long known that women are more likely than men to suffer depression, post-traumatic stress disorder and other anxiety disorders, all of which have been linked to chronic stress, says Temple University psychologist Debra Bangasser. But until recently, studies of people’s responses to such stress have focused primarily on men. Now, a growing number of scientists are studying what happens at the cellular and genetic levels in the brains of stressed-out rodents — male and female — to gain insight into the human brain. The studies are beginning to reveal differences between the sexes that may help explain the variability in their reactions and perhaps even provide much-needed insight into why stress-related disorders are more common in women than men. Recent findings reported at the annual meeting of the Society for Neuroscience, held in Chicago in October, show that a common stress hormone triggers different responses in specific brain cells of male and female animals. The differences make females less able than males to adapt to chronic stress. Other studies are exploring how exposure to the same hormone influences gene expression in a part of the brain that controls mood and behavior. Still other research suggests that a different hormone, associated with trust, could render females more susceptible than males to depression, anxiety and PTSD. © Society for Science & the Public 2000 - 2015.
By Ralph G. Neas In mid-February of 1979, I started experiencing tingling sensations in my feet and fingers. I told myself I was only feeling some residual effects from a bout with the flu several weeks before, and I caught the afternoon plane to Minneapolis to join my new boss, U.S. Sen. David Durenberger (R-Minn.), for several days of political meetings. That was on Sunday. On Tuesday, midway through a presentation, I began slurring my words and I found it hard to swallow. A local doctor, on hearing I’d had the flu, told me to go to my hotel room, take a couple of aspirin and call him in the morning. I spent the night moving from the bed to the couch to the chair to the floor, seeking relief from pain that was affecting more and more of my body. Just before dawn, I noticed that the right side of my face was paralyzed. On my way to the ER, the left side became paralyzed. I wasn’t having a recurrence of the flu. A spinal tap confirmed doctors’ suspicions that I’d come down with Guillain-Barré syndrome, or GBS, a rare neurological disorder that can cause total paralysis. Within 10 days I was so weakened by the spreading paralysis in my legs and arms that I could not get out of my bed at St. Mary’s, the Minneapolis hospital where I was being treated. Within three weeks, doctors performed a tracheostomy — connecting a mechanical respirator to my windpipe — because my ability to breathe was getting so poor.
Laura Sanders Pain can sear memories into the brain, a new study finds. A full year after viewing a picture of a random, neutral object, people could remember it better if they had been feeling painful heat when they first saw it. “The results are fun, they are interesting and they are provocative,” says neuroscientist A. Vania Apkarian of Northwestern University in Chicago. The findings “speak to the idea that pain really engages memory.” Neuroscientists G. Elliott Wimmer and Christian Büchel of University Medical Center Hamburg-Eppendorf in Germany reported the results in a paper online at BioRxiv.org first posted December 24 and revised January 6. The findings are under review at a journal, and Wimmer declined to comment on the study until it is accepted for publication. Wimmer and Büchel recruited 31 brave souls who agreed to feel pain delivered by a heat-delivering thermode on their left forearms. Each person’s pain sensitivity was used to calibrate the amount of heat they received in the experiment, which was either not painful (a 2 on an 8-point scale) or the highest a person could endure multiple times (a full 8). While undergoing a functional MRI scan, participants looked at a series of pictures of unremarkable household objects, such as a camera, sometimes feeling pain and sometimes not. Right after seeing the images, the people took a pop quiz in which they answered whether an object was familiar. Pain didn’t influence memory right away. Right after their ordeal, participants remembered about three-quarters of the previously seen objects, regardless of whether pain was present, the researchers found. © Society for Science & the Public 2000 - 2015.
Answered by Anne Masten, You raise one of the most intriguing questions in modern resilience science: Can adversity be good for development? The answer appears to be yes, depending on the timing and nature of the stresses. But it is important to note that it is a person's adaptive responses to life's challenges that are beneficial, not the exposure to adversity itself. Beneficial responses have been called steeling effects, stress inoculation and post-traumatic growth. Extreme deprivation or stress can clearly cause lasting life consequences. Yet many individuals endure, recover and thrive in the aftermath of devastating events. A few, such as Malala Yousafzai, Stephen Hawking or Oprah Winfrey, even become famous. What distinguishes them? An individual's resilience can be viewed as the capacity to adapt to adversity at a given point. Resilience is not innate, nor is it fixed. It can fluctuate throughout a person's lifetime and is influenced by a complex set of adaptive processes. Many of these protective systems improve with experience or require challenges to reach their full potential. On a biological and environmental level, our capabilities to fight off infections and respond to stress are both shaped by experience. For instance, we vaccinate our children to promote immunity to dangerous pathogens. Similarly, exposure to manageable levels of psychological stress can improve future adaptation abilities. It is important to remember, however, that too much adversity can deplete the resources any child or adult needs to muster resilience. There is psychological and neurobiological evidence that prolonged or overwhelming stress can wear down our body and mind. © 2016 Scientific American
Link ID: 21775 - Posted: 01.12.2016
By Tania Rabesandratana Here’s one trick to make yourself feel happier: Listen to your own voice—digitally manipulated to make it sound cheery. That’s one potential application of a new study, in which researchers modified the speech of volunteers as they read a short story by Japanese writer Haruki Murakami. The team then altered the voice’s pitch, among other features, to make it sound happy, sad, or fearful. (Compare this normal voice with the same voice modified to sound afraid.) Listening to their own modified voices in real time through a headset, only 16 of 109 participants detected some kind of manipulation. The rest took the voice’s emotion as their own, feeling sad or happy themselves. (The result was less clear for fear.) The researchers suggest that emotions expressed through our voices are part of an ancient, unconscious primate communication system, whereas we have more conscious control over the words we utter. The voice manipulation software is available online, so anyone can experiment with it. The scientists speculate that emotion manipulation could help treat psychiatric disorders like depression. It could also change the mood of online meetings or gaming, they say, or even lend more emotional impact to singing performances. © 2016 American Association for the Advancement of Science
When Jack O'Connor was 19, he was so desperate to beat his addictions to alcohol and opioids that he took a really rash step. He joined the Marines. "This will fix me," O'Connor thought as he went to boot camp. "It better fix me or I'm screwed." After 13 weeks of sobriety and exercise and discipline, O'Connor completed basic training, but he started using again immediately. "Same thing," he says. "Percocet, like, off the street. Pills." Percocet is the brand name for acetaminophen and oxycodone. Oxycodone is a powerful opioid. It's one of the most commonly prescribed painkillers, and is a key factor in one of the country's most pressing public health problems — an opioid addiction epidemic. It is a crisis that started, in part, from the over-prescription of painkillers, like Percocet, and then shifted to heroin, as people addicted to prescription drugs looked for a cheaper high. O'Connor is one of an estimated 2.5 million Americans addicted to opioids and heroin, according to the National Institute on Drug Abuse. Over three years, he detoxed from prescription painkillers — and heroin — more than 20 times. Each time, he started using again. So why is it so hard for opioid addicts to quit? You can boil it down to two crucial bits of science: the powerful nature of opioids and the neuroscience behind how addiction hijacks the brain. "The first recording of opioid use was 5,000 years ago," says Dr. Seddon Savage, an addiction and pain specialist at Dartmouth College. It was "a picture of the opium poppy and the words 'the joy plant.' "
Keyword: Drug Abuse
Link ID: 21773 - Posted: 01.11.2016
Don’t blame impulsive people for their poor decisions. It’s not necessarily their fault. Impulsivity could result from not having enough time to veto our own actions. At least that is the implication of a twist on a classic experiment on free will. In 1983, neuroscientist Benjamin Libet performed an experiment to test whether we have free will. Participants were asked to voluntarily flex a finger while watching a clock-face with a rotating dot. They had to note the position of the dot as soon as they became aware of their intention to act. As they were doing so, Libet recorded their brain activity via EEG electrodes attached to the scalp. He found that a spike in brain activity called the readiness potential, which precedes a voluntary action, occurred about 350-milliseconds before the volunteers became consciously aware of their intention to act. The readiness potential is thought to signal the brain preparing for movement. Libet interpreted his results to mean that free will is an illusion. But we’re not complete slaves to our neurons, he reasoned, as there was a 200-millisecond gap between conscious awareness of our intention and the initiation of movement. Libet argued that this was enough time to consciously veto the action, or exert our “free won’t”. While Libet’s interpretations have remained controversial, this hasn’t stopped scientists carrying out variations of his experiment. Among other things, this has revealed that people with Tourette’s syndrome, who have uncontrollable tics, experience a shorter veto window than people without the condition, as do those with schizophrenia. © Copyright Reed Business Information Ltd.
By Veronique Greenwood Last year a new sleep drug called Belsomra came on the market, featuring a mechanism unlike any other pill: it mimics narcolepsy. That might sound odd, but the potential users are many. More than 8.5 million Americans take prescription sleep aids, and many others use snooze-inducing over-the-counter medications. All these pills, including Belsomra, do one of two things: they enhance the effects of the neurotransmitter GABA, known for quieting brain activity, or they arrest the actions of neurotransmitters that keep the brain aroused. Yet it's not quite as simple as flipping a switch; the drugs have a range of side effects, including daytime drowsiness, hallucinations and sleep-eating. Here's an overview of the sleeping pills currently available in the U.S.—plus a look at cognitive-behavior therapy for insomnia, which may be more successful than drugs alone. It requires a lot more work than popping a pill, but cognitive-behavior therapy for insomnia (CBT-I) has been shown to successfully alleviate sleep problems. Aimed at developing healthy habits, CBT-I comes with a lot of homework—between weekly or so visits with a specialist, a patient keeps track of hours spent in bed and hours sleeping and uses the bed only for sleep and sex. The patient must stay up until an established bedtime and get up on awakening, generating a sleep deficit that makes it easier to fall asleep at the right time. Avoiding caffeine and alcohol after 4 P.M. and timing exercise so that it doesn't interfere with drowsiness are also part of the system. © 2016 Scientific American
Link ID: 21770 - Posted: 01.11.2016
by Laura Sanders Young babies get a bad rap. They’re helpless, fickle and noisy. And even though they allegedly sleep for 16 hours a day, those hours come in 20-minute increments. Yet hidden in the chaos of a young infant’s life are some truly magnificent skills — perceptual feats that put adults to shame. So next time your baby loses it because she can’t get her thumb into her mouth, keep in mind that her strengths lie elsewhere. Six-month-old babies can spot subtle differences between two monkey faces easy as pie. But 9-month-olds — and adults — are blind to the differences. In a 2002 study of facial recognition, scientists pitted 30 6-month-old babies against 30 9-month-olds and 11 adults. First, the groups got familiar with a series of monkey and human faces that flashed on a screen. Then new faces showed up, interspersed with already familiar faces. The idea is that the babies would spend more time looking at new faces than ones they had already seen. When viewing human faces, all of the observers, babies and adults alike, did indeed spend more time looking at the new people, showing that they could easily pick out familiar human faces. But when it came to recognizing monkey faces, the youngsters blew the competition out of the water. Six-month-old babies recognized familiar monkey faces and stared at the newcomers longer. But both adults and 9-month-old babies were flummoxed, and looked at the new and familiar monkey faces for about the same amount of time. © Society for Science & the Public 2000 - 2015
By Christof Koch While “size does not matter” is a universally preached dictum among the politically correct, everyday experience tells us that this can't be the whole story—under many conditions, it clearly does. Consider the size of Woody Allen's second favorite organ, the brain. Adjectives such as “highbrow” and “lowbrow” have their origin in the belief, much expounded by 19th-century phrenologists, of a close correspondence between a high forehead—that is, a big brain—and intelligence. Is this true? Does a bigger brain make you necessarily smarter or wiser? And is there any simple connection between the size of a nervous system, however measured, and the mental powers of the owner of this nervous system? While the answer to the former question is a conditional “yes, somewhat,” the lack of any accepted answer to the second one reveals our ignorance of how intelligent behavior comes about. The human brain continues to grow until it reaches its peak size in the third to fourth decade of life. An MRI study of 46 adults of mainly European descent found that the average male had a brain volume of 1,274 cubic centimeters (cm3) and that the average female brain measured 1,131 cm3. Given that a quart of milk equals 946 cm3, you could pour a bit more than that into a skull without any of it spilling out. Of course, there is considerable variability in brain volume, ranging from 1,053 to 1,499 cm3 in men and between 975 and 1,398 cm3 in women. As the density of brain matter is just a little bit above that of water plus some salts, the average male brain weighs about 1,325 grams, close to the proverbial three pounds often cited in U.S. texts. © 2016 Scientific American