By Tina Hesman Saey Mice and cats don’t usually agree, but both animals have the same bright idea about night vision. Cats, rats, mice and other nocturnal mammals arrange DNA in some eye cells to form miniature lenses that help focus light, a new study shows. Scientists at the Ludwig-Maximilians University Munich in Germany and colleagues discovered the unusual DNA arrangement while investigating the function of several genes in the rod cells of mouse eyes, says Boris Joffe, one of the authors of the new study, which appears in the April 17 Cell. Rod cells are light-gathering cells in the retina of the eye. They operate under low-light conditions, while cone cells perform the light-gathering duty when it is bright. Usually active genes are located in the part of the DNA that is at the center of a cell’s nucleus. There, the genes have easy access to the cellular machinery that rewrites instructions encoded in the DNA into RNA. Inactive DNA is pushed to the periphery of the nucleus, where it is out of the way. But rod cells in the mouse retina shove active genes to the outside of the nucleus, the researchers found. The center of the nucleus is instead occupied by densely-packed inactive DNA called heterochromatin. Mice put this type of DNA front and center in their rod cells. © Society for Science & the Public 2000 - 2009

Keyword: Vision; Genes & Behavior
Link ID: 12772 - Posted: 06.24.2010

By TARA PARKER-POPE The transition from high school to college is tough for most students. But for those with attention deficit hyperactivity disorder, university life poses a host of academic, medical and personal challenges. Students with A.D.H.D. struggle to stay focused on their studies and to meet the organizational demands of schoolwork. Although some children appear to outgrow the disorder as they age, doctors say that as many as two-thirds have symptoms that persist into adulthood. Medications help, but students need a support system of family, teachers and friends. Last year, The Journal of Pediatric Nursing published a report in which college students with A.D.H.D. recounted the role family members played in their academic success in high school. Mothers made flash cards, gave them books on tape, proofread papers and helped them prioritize. Even school friends would tap them in class if they “zoned out.” When teenagers leave for college, that personal support system disappears. They move away from parents, trusted teachers and the pediatrician who prescribes their medication. For a teenager struggling to stay organized, the unusual class schedules, hourlong lectures, late-night study sessions and disrupted sleep routines of college can be a nightmare. Studies suggest that college students with A.D.H.D. are at greater risk for academic and psychological difficulties, and have lower grade-point averages, than peers without the problem. “We have found that there are a lot of significant barriers these students face,” says Dr. Mark H. Thomas, a physician at the University of Alabama student health center, who is part of a campuswide effort to provide additional resources to students with the disorder, including a series of podcasts on how to cope. Copyright 2009 The New York Times Company

Keyword: ADHD
Link ID: 12771 - Posted: 06.24.2010

by Sandrine Ceurstemont If you're surrounded by smiling faces, you're more likely to feel happy than if everyone around you is looking glum. But we know relatively little about how emotions spread from one person to another. The Chameleon Project, a collaboration between artist Tina Gonsalves - currently in residence at the MIT Media Lab - and neuroscientists could help. The installation involves using face recognition software that analyses a person's expression as they walk into a room and shows them a video portrait of another person displaying a related emotion. The project employs an algorithm developed by neuroscientist Chris Frith from University College London that tries to read and respond to the emotions of a person in the same way another person would. That algorithm builds on research that suggests that when we interact with someone, we try to reach a neutral emotional state where communication can occur more easily. People tend to mirror the expression of someone who is happy or scared, but try to calm down someone who is angry. As well as producing a unique art installation, the Chameleon Project should provide neuroscientists with new insight into how people respond to less-studied emotions such as anger. The underlying technology could be used with little modification for research into empathy – for example, investigating how people with mental illnesses like autism and schizophrenia respond to the emotions of people around them. © Copyright Reed Business Information Ltd

Keyword: Emotions; Robotics
Link ID: 12770 - Posted: 06.24.2010

by Helen Thomson If somebody is in your personal space, you can thank a bunch of "mirror neurons" in your frontal lobes for helping you to decide how you should respond. That's the conclusion of a study by German researchers that suggests mirror neurons, which fire both when you perform an action and when you watch someone else perform it, have greater responsibilities than were previously realised. Antonino Casile from the Hertie Institute for Clinical Brain Research at the University of Tübingen in Germany and colleagues probed the personal space of two rhesus monkeys, while monitoring their mirror neurons that respond to seeing a human grasping an object some distance away. Monkey do The team compared how the neurons fired when a person grabbed a metallic object within a monkey's reach and again from a greater distance. They found that rather than simply responding to the action, the mirror neurons also responded to whether or not the action was close enough for the monkey to intervene. Specific subsets of neurons responded to grasping actions inside and outside of a monkey's reach. Of the mirror neurons that fired when a monkey grabbed an object for itself around a quarter fired only in response to seeing a person grasp an object within the monkey's reaching distance while a different quarter responded to actions outside that space. © Copyright Reed Business Information Ltd

Keyword: Vision
Link ID: 12769 - Posted: 06.24.2010

By Michael Balter When a rare genius like Albert Einstein comes along, scientists naturally wonder if he had something special between his ears. The latest study of Einstein's brain concludes that certain parts of it were indeed very unusual and might explain how he was able to go where no physicist had gone before when he devised the theory of relativity and other groundbreaking insights. The findings also suggest that Einstein's famed love of music was reflected in the anatomy of his brain. When Einstein died in 1955 at Princeton Hospital in New Jersey, his brain was removed by a local pathologist named Thomas Harvey, who preserved, photographed, and measured it. A colleague of Harvey's cut most of the brain into 240 blocks and mounted them on microscope slides. From time to time, he sent the slides to various researchers, although few publications resulted. Harvey, who moved around the United States several times in the course of his career, kept the jar containing what remained of the brain in cardboard box. Finally, in 1998, Harvey--who died in 2007--gave the jar to the University Medical Center of Princeton, where it remains today. The first anatomical study of Einstein's brain was published in 1999, by a team led by Sandra Witelson, a neurobiologist at McMaster University in Hamilton, Canada. Working from Harvey's photographs, which were all that remained of the whole brain, Witelson's team found that Einstein's parietal lobes--which are implicated in mathematical, visual, and spatial cognition--were 15% wider than normal parietal lobes. The team also found other unusual features in the parietal region, although some of these were questioned by other researchers at the time. One parameter that did not explain Einstein's mental prowess, however, was the size of his brain: At 1230 grams, it fell at the low end of average for modern humans. © 2009 American Association for the Advancement of Science

Keyword: Intelligence
Link ID: 12768 - Posted: 06.24.2010

Peter Aldhous, San Francisco The obvious schizophrenic symptoms - such as having animated conversations with people who aren't really there - can be controlled by antipsychotic drugs. However, people with schizophrenia find their difficulties with learning, remembering, making decisions and processing information even more problematic than hallucinations. These symptoms have proved hard to treat, making it difficult for people with the condition to hold down a job or deal with social situations. Now there is hope. At the San Francisco Veterans Affairs Medical Center, a team led by Sophia Vinogradov has put 55 volunteers with schizophrenia through "brain fitness" training, using software made by the firm Posit Science, also in San Francisco. The brain fitness software starts by giving volunteers basic tasks such as identifying whether the pitch of various tones rises or falls (see "Can I hear that again?") and ends with a comprehension test of a spoken narrative. After the training, Vinogradov's volunteers performed better in cognitive tests, including tests of verbal learning and memory, compared with a control group who played simple computer games. The improvements were about twice as great as those seen in previous trials of cognitive training, Vinogradov's team reports in a paper to appear in The American Journal of Psychiatry. Susan McGurk of Dartmouth Medical School in Hanover, New Hampshire, who has analysed the evidence from earlier trials, calls Vinogradov's results "exciting". © Copyright Reed Business Information Ltd

Keyword: Schizophrenia
Link ID: 12767 - Posted: 06.24.2010

By Coco Ballantyne A drug commonly used to treat heroin addiction appears to ease the symptoms of fibromyalgia, a poorly understood but potentially debilitating condition that affects up to 12 million people in the U.S. (4 percent of the population), a small pilot study has found. "We have a medication that seems to have low side effects and seems to reduce pain and fatigue [in fibromyalgia patients]," says Jarred Younger, a pain researcher at Stanford University School of Medicine and co-author of the study appearing today in Pain Medicine. "I think this is a potential treatment to add to the doctor's arsenal," he adds, noting that longer studies involving more patients are needed to confirm the results. Fibromyalgia, a mysterious ailment whose symptoms include chronic widespread muscle pain, fatigue, sleep problems, anxiety and depression, often appears between the ages of 34 and 53 and is more common in women (affecting 5 percent of women and 1.6 percent of men in the U.S.), the researchers report. The U.S. Food and Drug Administration (FDA) has approved three drugs for treating fibromyalgia, but many patients don't respond to them, Younger says. For 14 weeks, Younger and his colleague Sean Mackey, chief of the pain management division at Stanford, monitored the symptoms of 10 women ages 22 to 55 with fibromyalgia before, during and after they took small doses (4.5 milligrams per day) of naltrexone, a drug that for about three decades has been used to wean addicts off of heroin and other street drugs. (Naltrexone works by latching onto nerve cell receptors where heroin and other opioid drugs would dock, thus blocking their ability to act on the cells and induce a feeling of being high.) Using handheld computers, the women reported the severity of their daily symptoms on a scale of one to 100 (100 being the most severe). Every two weeks, they visited the researchers who downloaded the data entered in the computers and ran tests to measure the women's pain thresholds for pressure, heat and cold applied to the skin. © 1996-2009 Scientific American Inc.

Keyword: Drug Abuse; Stress
Link ID: 12766 - Posted: 06.24.2010

Millions of people carry two common genetic variants that significantly increase the risk of stroke, researchers have found. A stroke is a brain injury caused by a lack of blood. It is the third-leading cause of death in the U.S., and 50,000 Canadians have strokes each year. In Wednesday's online issue of the New England Journal of Medicine, researchers in the U.S. said they found two genetic variants on chromosome 12 that are linked to ischemic strokes — the most common type of stroke, caused by blocked blood vessels in the brain. "Even though this variant is common, it has a modest effect on stroke risk," said study author Eric Boerwinkle, chair in human genetics at University of Texas Health Science Center at Houston. "Therefore, everyone, whether they carry this variant or not, should be aware of the risk factors for stroke, such as high blood pressure and smoking, and do everything they can to avoid those risk factors," he added in a release. To find the variants, researchers compared the genomes of 1,544 individuals who developed stroke with the genomes of 18,058 individuals who did not. © CBC 2009

Keyword: Stroke; Genes & Behavior
Link ID: 12765 - Posted: 06.24.2010

By RONI CARYN RABIN Pregnant women who took a popular epilepsy drug, also widely used to treat migraines, pain and psychiatric disorders, had children whose I.Q. scores were significantly lower than those whose mothers took a different antiseizure medication, a new study has found. The drug, valproate, sold generically and under the brand name Depakote, remains the second-most-popular antiseizure medication used for epilepsy, but earlier studies found that use during pregnancy also increased the risk of developmental delays and major malformations. The risks that other epilepsy drugs may pose are not clear, experts say. While some are likely to be safer than others, there have not been enough studies to guide patients and their doctors. About half of the women who take valproate are not epileptics. The new study is to be published on Thursday in The New England Journal of Medicine. Three-year-olds whose mothers had taken valproate during pregnancy had I.Q. scores that were nine points lower on average than children whose mothers had taken a different antiseizure medication, lamotrigine. The I.Q. scores of toddlers whose mothers took valproate were also lower than scores of children whose mothers took two other antiseizure medications, phenytoin and carbamazepine. Copyright 2009 The New York Times Company

Keyword: Epilepsy; Development of the Brain
Link ID: 12764 - Posted: 04.16.2009

By Carolyn Y. Johnson CAMBRIDGE - Studying a species known to chase its own tail may seem an unlikely way to better understand the human mind. But scientists at Harvard University's new Canine Cognition Lab hope to gain insight into more than the psychology of dogs from visiting pet pooches - including an alert German shepherd named Celia and a rottweiler called Taylor who loves to eat chicken. Researchers have long looked at other species' reasoning abilities and behavior to discern what makes humans distinct. The Harvard team is now turning to dogs because on certain tasks, such as understanding pointing, dogs easily outperform animals much more closely related to humans, even chimpanzees. Scientists are also drawn to dogs because of their unique history growing up in the same environment as people, and they hope to learn whether domestication has led to dogs that think and act more like their masters - or whether we just think they have human traits. "Here's this species we live with. Everyone has their views about how smart they are. No doubt we are overinterpreting - and in some cases underinterpreting," said Marc Hauser, a Harvard professor who has long studied cognition in cottontop tamarin monkeys and who heads the new lab. "To what extent is an animal that's really been bred to be with humans capable of some of the same psychological mechanisms?" Can dogs understand such abstract concepts as "same," for example? Or, can dogs be patient? To answer such canine conundrums, Hauser is recruiting both purebreds and mutts and running them through simple tests. In return, they earn tasty treats. © 2009 NY Times Co

Keyword: Intelligence; Evolution
Link ID: 12763 - Posted: 06.24.2010

By Coco Ballantyne Cholesterol-busting statins may lower the odds of suffering from a heart attack or stroke, but they don't appear to ward off dementia as researchers had hoped, a new review of clinical trials suggests. "There is really no evidence that statins do prevent dementia, especially in elderly people (age 70 and older)," says Bernadette McGuinness, a geriatrician at Queen's University in Belfast, Ireland, and co-author of the study published today in The Cochrane Library. McGuinness and her colleagues analyzed the findings of two large clinical trials probing the health effects of statins: the Medical Research Council/British Heart Foundation Heart Protection Study (HPS), which investigated the effects over five years of simvastatin (Zocor) in 20,536 patients, and The Prospective Study of Pravastatin in the Elderly at Risk (PROSPER) trial, which followed 5,804 patients taking pravastatin (Pravachol) for an average of 3.2 years. Participants in these trials ranged in age from 40 to 82. In both studies, the odds of developing Alzheimer's and other forms of dementia were about the same among patients taking statins and not taking statins, McGuinness says. Earlier research has suggested that statins might help reduce the risk of developing Alzheimer's by lowering cholesterol, which helps in the production of beta-amyloid protein (the suspected culprit in the disease), says Benjamin Wolozin, a neuroscientist at Boston University. © 1996-2009 Scientific American Inc

Keyword: Alzheimers
Link ID: 12762 - Posted: 06.24.2010

By Sydney Spiesel Autism can present in many ways—hence "autism spectrum disorders"—but that range is nothing compared with the diverse techniques that parents use in their attempts to cure, ameliorate, or disrupt the progress of the disease. In the 60-plus years since autism was first described, many methods to treat it have been proposed—one research paper identified 111 recognized treatments or strategies. Studies have found that parents try an average of between 4.3 and seven interventions simultaneously; one family reported using 47 different treatments at one time. Alas, almost none of these treatments are evidence-based, and some have been clearly demonstrated to be worthless. In dealing with other medical problems, like the common cold, I've always annoyed medication-seeking parents by pointing out the obvious: If there is any illness for which 100 treatments are available, you can be sure that none of them works. But with autism, the stakes are much higher. It is especially difficult to know where to look for treatments when a condition is poorly defined and characterized. There are no laboratory tests or gross anatomical findings that establish the diagnosis, but experienced clinicians often "know it when they see it" almost instantly, especially when patients are severely affected. I once made the diagnosis from a dog-eared snapshot. Since most of the ways we diagnose autism are based on behavior, we can't rely on biological, structural, or chemical findings to determine if a treatment is working. We primarily measure success based on a patient's change, or lack thereof, in behavior. 2009 Washington Post.Newsweek Interactive Co. LLC

Keyword: Autism
Link ID: 12761 - Posted: 06.24.2010

by Celeste Biever Savant-like skills, such as astounding memory, perfect pitch or the ability to multiply very high numbers together, may be much more common among people with autism than previously thought. A new study of about 100 adults with autism shows that one third have skills that stand out, both in comparison with their other abilities and with the skills of the general population. Previous studies put the prevalence of savantism in autistic people as around 1 in 10. "People often focus on the things people with autism can't do," says Patricia Howlin of the Institute of Psychiatry at King's College in London, who led the study. "One of the things our study illustrates is that these are people who do have special skills but they are not being used." The notion of the savant – someone who has a skill that is exceptional both compared to the general population and to that person's other skills – has long captured the imagination of cognitive scientists and the general public alike. But despite this fascination, the connection between autism and savantism remains mysterious. Some studies indicate that there are more savants within the autistic population than among the general population and among the populations of people with other mental difficulties. Putting an exact figure on the prevalence of such special skills among people with autism, however, has proved difficult. © Copyright Reed Business Information Ltd.

Keyword: Autism
Link ID: 12760 - Posted: 06.24.2010

by Ewen Callaway If rollercoasters and rock concerts sound fun but leave you with a headache, a drug-free sugar pill might be all that's needed to soothe you. Thrill-seekers enjoy a stronger placebo response than people with more restrained personalities, new research shows. It's too early to prescribe phoney pain treatments based on personality tests, says neuroscientist Petra Schweinhardt, of McGill University in Montreal, whose team tested 22 male university students. But if confirmed in larger trials, her team's findings could help pharmaceutical companies avoid testing experimental drugs on people with strong placebo responses, she says. Her team injected a pain-inducing saline solution into the left and right legs of willing volunteers for 20 minutes. "It's a dull pain, a dumb pain, it's aching, it's annoying," she says. Before the injection, her team told volunteers they were testing an experimental analgesic cream – really just skin lotion. To make the ruse more believable, researchers said they would test one leg with the treatment and one leg with a non-medicated lotion. "We really told them the whole story in order to counteract any doubts in the treatment," Schweinhardt says. Volunteers then rated their pain across both trials, and the difference amounted to the placebo response. © Copyright Reed Business Information Ltd.

Keyword: Pain & Touch
Link ID: 12759 - Posted: 06.24.2010

by Richard Webb I WAS rounding the corner to the bus stop when it hit me - a bright shaft of sunlight smack between the eyes. My reaction was immediate: an unpleasant prickling in my nose, a quickening of my breath, an uncontrollable watering of my eyes. Then, almost as quickly as the sensation came, relief, blessed relief. Aaaaa-tisshoo! A sneeze. It wasn't the first time. In fact, the same thing happens every time I go into the sun. For a long time, I thought it was a quirk all of my own. Then a friend mentioned she was similarly afflicted. Next my mother came out of the closet. With a bit of digging around I came to a startling realisation: not only am I not alone, but the "photic sneeze reflex" is actually common. Quite how common, no one knows exactly - but anything between 1 in 10 and 1 in 3 of us might be affected. The more I looked, the more mysterious things became. Sunlight is the most widespread, but by no means the only, odd stimulus that sets off sneezing. Thinking about sex, eyebrow tweezing, eating chocolate or a mint, or drinking a glass of wine - all these activities can leave us groping around for handkerchiefs. Members of one Kuwaiti family were even reported to sneeze whenever they had a full stomach - a phenomenon dubbed "snatiation". Then there was the case of the medical student who sneezed with almost clockwork precision around 8.20 every morning. © Copyright Reed Business Information Ltd.

Keyword: Miscellaneous
Link ID: 12758 - Posted: 06.24.2010

By Kayt Sukel Research has shown that lead kills neurons (nerve cells), resulting in smaller brains. It has long been hypothesized that such changes in the brain caused by childhood lead exposure may be behind a higher incidence of poor cognitive performance and criminal behavior. And although it is difficult to disentangle the confounding effects of race, class and economics, a recent study by Kim Dietrich, a professor of environmental health at the University of Cincinnati, found that individuals who suffered from the highest lead exposure as children had the smallest brain sizes—as well as the most arrests. "That early lead exposure was associated with smaller volumes of cortical gray matter [the parts of the brain rich in neural cell bodies and synapses] in the prefrontal area," he says. "And the fact that we saw both criminal behavior and volume loss in this critical area for executive function is probably more than just a coincidence." That may be so, however, new scientific studies across several animal species, including humans, are challenging the notion that brain size alone is a measure of intelligence. Rather, scientists now argue, it is a brain's underlying organization and molecular activity at its synapses (the communication junctions between neurons through which nerve impulses pass) that dictate intelligence. Two years ago, Paul Manger, a professor of health sciences at the University of the Witwatersrand in Johannesburg, South Africa, caused quite a stir when he referred to the beloved bottlenose dolphin, owner of a large, nearly human-size brain, as "dumber than a goldfish." © 1996-2009 Scientific American Inc.

Keyword: Intelligence; Evolution
Link ID: 12757 - Posted: 06.24.2010

By Nathan Seppa A single episode of low blood sugar severe enough to require prompt medical attention increases a person’s risk of developing dementia in old age, a study in people with diabetes suggests. More than one bout of hypoglycemia seems to heighten the risk even further, researchers report in the April 15 Journal of the American Medical Association. While chronically high blood sugar is known to increase the risk of dementia and other health problems, less is understood about the long-term effects of periodic low blood sugar, says study coauthor Rachel Whitmer, an epidemiologist at the Kaiser Permanente Division of Research, in Oakland, Calif. She and her colleagues analyzed medical records from a Kaiser Permanente registry dating from 1980 to 2002 and identified nearly 17,000 people who had type 2 diabetes but no signs of dementia, mild cognitive impairment or even memory complaints during the time span. The people averaged 65 years of age as of 1994. The scientists noted any low blood sugar episodes that required a trip to a hospital or other emergency facility. For such treatment, Whitmer says, a patient would have gone beyond just being shaky and weak, as happens with mildly low blood sugar. “These were events where patients may have fainted or passed out or may have been unable to communicate with others — and were brought in,” she says. © Society for Science & the Public 2000 - 2009

Keyword: Alzheimers; Obesity
Link ID: 12756 - Posted: 06.24.2010

By Bryan Walsh Monday Medical science has deciphered many of the body's workings, down to the level of the gene, and isn't too far from using stem cells to repair its hobbled organs. But in many ways, the human body remains a vast and peculiar mystery. Take the common itch. Everyone knows from experience that a good scratch can cure an itch, but doctors still don't understand the physiological mechanism behind the itch-scratch connection. And that ignorance can have serious medical consequences. The common itch isn't so benign in many conditions, including shingles and AIDS, which can cause uncomfortably severe itching. Sometimes itching can occur inexplicably, without any apparent physical cause, and a patient's unchecked scratching can lead to excessive skin damage or worse. (Read "The Year in Medicine 2008: From A to Z.") But a study published today in the journal Nature Neuroscience offers some hope of lasting relief. A group of neuroscientists led by Glenn Giesler at the University of Minnesota, Minneapolis, hypothesized that the mechanism by which scratching relieves an itch takes place not along the nerve fibers of itchy skin but deep within the central nervous system — specifically, in the spinothalamic tract (STT) neurons in the spinal cord, which transmit information about pain, temperature and touch to the brain. (Previous studies have shown that STT neurons can be activated with the application of an itch-producing chemical like histamine and that the neurons send that itch sensation to the brain.) © 2009 Time Inc.

Keyword: Pain & Touch
Link ID: 12755 - Posted: 06.24.2010

A new drug which shows promise as a treatment for Alzheimer's disease has been developed by UK scientists. The Proceedings of the National Academy of Sciences reports the drug, CPHPC, removes a protein thought to play a key role in Alzheimer's from the blood. Tests at the University College London found the protein also disappeared from the brains of five Alzheimer's patients given the drug for three months. Longer and larger scale clinical studies are now being planned. The protein - serum amyloid P component (SAP) is always present in both the sticky clumps (plaques) and the tangles of nerve fibres that are found in the brains of people with Alzheimer's disease, and are thought to damage healthy cells. It appears to protect both structures from breaking up, and has also been shown - in lab experiments at least - to promote formation of the amyloid protein which forms the damaging plaques. There is also some evidence that SAP itself can damage brain cells directly. Two of the big potential advantages CPHPC are that it is not broken down once inside the body, and it has a very specific action, not interacting with cells at all, thus reducing the risk of side effects. The researchers expected a depletion of SAP in the five patients' blood - but were taken aback at the drug's apparent effect on the brain. By using laboratory tests they were also able to reveal both the molecular process underpinning the effect of the drug, and the way in which SAP accumulates in the brain in Alzheimer's disease. The study also confirmed that use of the drug - and the removal of SAP from the brain - had no side effects on the patients. CPHPC has already been given to patients with other diseases without any any adverse effects. (C)BBC

Keyword: Alzheimers
Link ID: 12754 - Posted: 04.14.2009

Does postpartum depression serve some evolutionary purpose? —Clint Johnson, Ridgecrest, Calif. Anthropologist Edward H. Hagen of Washington State University replies: Postpartum depression (PPD), which af­flicts 10 to 15 percent of new mothers, may have evolved as a strategic response to a lack of social support because it helped in passing on genes successfully. Many doc­tors believe PPD is triggered by the changes in a mother’s hormones after giving birth, yet studies have failed to find much evi­dence for a link between extreme hormone fluctuations and PPD. The fact that fathers, who do not experi­ence such changes, also suffer from PPD is strong evidence that it is not “just hormones.” The finding that PPD often plagues people who have marital problems or little outside support led biologists Randy Thornhill and F. Bryant Furlow of the University of New Mexico and me independently to propose that PPD has an evolved function. Many animals improve their chances of passing on their genes if they desert their young when food or parenting help is scarce and invest instead in future offspring that are more likely to survive and reproduce. This “parental investment theory” should apply especially well to humans. Human children are “expensive” to raise, requiring years of parenting before they can survive on their own. When a mother lacks support from the father or other family members, she may unconsciously conclude she cannot successfully raise her infant. The ensuing emotional pain from PPD operates somewhat like physical pain: stop what you’re doing—it’s harming your reproductive fitness! Studies confirm that mothers with PPD do significantly reduce parenting efforts and often have thoughts of harming their baby. © 1996-2009 Scientific American Inc.

Keyword: Depression; Evolution
Link ID: 12753 - Posted: 06.24.2010