By NICHOLAS BAKALAR Using functional magnetic resonance imaging, researchers have found brain changes in preschool-age children with depression that are not apparent in their nondepressed peers. The study, in the July issue of The Journal of the American Academy of Child & Adolescent Psychiatry, examined 23 children 4 to 6 years old who had been diagnosed with depression and 31 of their healthy peers. Researchers used well-validated tests to diagnose depression, and eliminated from the study children with neurological disorders, autism or developmental disorders, or who had been born prematurely. None of the subjects was taking antidepressants. The children underwent M.R.I. brain scans while viewing pictures of happy, sad, fearful or neutral faces. The researchers found that right amygdala and right thalamus activity was significantly greater in the depressed children than in the others, a finding that has also been observed in depressed adolescents and adults. “We found something in the brain that is aligned with the idea of neurobiological models of depression — which parts of the brain are involved and how they interact,” said the lead author, Michael S. Gaffrey, an assistant professor in the department of psychiatry at Washington University in St. Louis. “We can begin to use this information in conjunction with other information — symptoms, other biological markers — to identify and eventually prevent and treat this disorder.” Copyright 2013 The New York Times Company

Keyword: Depression; Development of the Brain
Link ID: 18371 - Posted: 07.13.2013

By Bruce Bower A surprisingly simple decision-making tool shows promise as a way for physicians to identify people with depression. An answer to the first of four questions was all that researchers usually needed to identify women who weren’t depressed, say psychologist Mirjam Jenny of the Max Planck Institute for Human Development in Berlin and her colleagues. Using all four questions, this tool spotted depressed women about as well as two more-complex methods, Jenny’s team reports June 24 in the Journal of Applied Research in Memory and Cognition. If the findings hold up in other studies, physicians and other professionals with no mental-health training could use this brief technique to tag individuals who need thorough depression evaluations. “This decision tree can be used to screen for depression, but not to reach a final diagnosis,” Jenny says. Her team drew on data from 1,382 German women who completed a 21-item screening questionnaire for depression on two occasions, separated by 18 months. Based on this measure, depression initially affected 3.6 percent of the sample, or 50 individuals, and later appeared in 1.9 percent of the sample, or 26 individuals. Women’s initial responses to a handful of items that best predicted whether they would rank as depressed 18 months later were used to create a four-question decision tree. The first question in the tree — “Have you cried more than usual in the last week?” — led the pack in identifying cases of depression. A “no” response to this or any of the other three questions — which inquired about feelings in the last week of disappointment or self-hate, discouragement about the future and personal failure — exempted women from being categorized as depressed. Those who responded “yes” to all four questions were classified as depressed. © Society for Science & the Public 2000 - 2013

Keyword: Depression
Link ID: 18370 - Posted: 07.13.2013

Heidi Ledford The growth of new nerves in and around prostate cancers spurs tumours to grow and invade other tissues, studies in mice have shown. The results, published today in Science1, could steer researchers towards novel approaches to treating cancer. Although it is not yet clear whether the mechanism occurs in humans — or in cancers affecting other organs — an analysis of samples from 43 patients with prostate cancer found that nerve density was high in patients who fared poorly in the clinic. “It’s a catalytic paper,” says John Isaacs, a cancer researcher at the Johns Hopkins Medical Institutions in Baltimore, Maryland, who was not affiliated with the study. “People may now focus on trying to tackle these unanswered questions.” Previous work had shown that cancer cells sometimes migrate along nerves, and that this process can be associated with poor responses to therapy2. To learn more, Claire Magnon and Paul Frenette of the Albert Einstein College of Medicine in New York and their colleagues studied tumour development in mice injected with human prostate cancer cells. The resulting tumours, they saw, were infiltrated with certain types of nerve fibres. Chemically destroying those nerves prevented the development of tumours in the prostate. Furthermore, the team found that another class of nerves was associated with tumour spread, and that blocking certain receptors on those nerves prevented the cancer from invading nearby lymph nodes. © 2013 Nature Publishing Group

Keyword: Development of the Brain
Link ID: 18369 - Posted: 07.13.2013

by Emily Underwood "Antibrain" antibodies that slip through the placenta from mother to fetus during pregnancy may account for roughly a quarter of autism cases, a new study suggests. Some scientists say the work could lead to a blood test that accurately predicts whether a mother will bear a child with this immune-triggered form of the disorder—a claim that's raising eyebrows among skeptics. Autism spectrum disorder (ASD), a range of communication and social deficits estimated to affect 1 in 88 children, is now largely thought to be a neurodevelopmental malady that begins in the womb. For years, many researchers have brushed aside the idea that an out-of-whack immune response could contribute to this, preferring to focus on genetic factors that could derail typical brain development, says immunologist Judy Van de Water. Over the past decade, however, she and her colleagues at the University of California (UC), Davis, as well as several other research groups, have been slowly building a case for the role of an immune disorder in a subset of autism cases. "We just didn't quit," she says. In 2008, Van de Water found that roughly a quarter of 61 women with autistic children carried in their blood an unusual group of antibodies—large, Y-shaped proteins with sticky ends that normally bind to and destroy foreign or potentially harmful microbes. Some of these, called autoantibodies, occasionally go rogue and attack the body's healthy cells, causing autoimmune diseases such as lupus and rheumatoid arthritis. The higher the level of autoantibodies in the mother's blood, the more severe the child's autistic symptoms, Van de Water observed. She hypothesized that these autoantibodies were attacking proteins necessary for fetal brain development. © 2010 American Association for the Advancement of Science

Keyword: Autism; Neuroimmunology
Link ID: 18368 - Posted: 07.11.2013

Josh Howgego Thresher sharks can use their lengthy tail fins to swat sardines from shoals, researchers have found by taking underwater footage. Such tactical use of the tail fin during hunting — which was previously observed only in mammals such as dolphins and killer whales1 — might indicate that sharks are more intelligent than scientists thought. Pelagic thresher sharks (Alopias pelagicus) are nocturnal and notoriously shy. Researchers have long suspected that the shark uses its tail — which makes up half of its body length — to stun its prey, but the behaviour has not been documented before under natural conditions2. Simon Oliver, lead investigator of the Thresher Shark Research and Conservation Project, and his colleagues studied the sharks off the coast of Cebu, an island in the Philippines. Oliver, who is based at the University of Liverpool, UK, has been watching the animals during the day since 2005, but he hadn’t seen the sharks hunting until some divers saw it happening and phoned him. “Immediately I dropped everything and went to investigate,” he says. The sharks hunt by first lunging into a school of fish, priming their tails as they move in. They then swipe the tail in a trebuchet-like motion through an arc of 180o in just one-third of a second — fast enough to both physically hit the fish and to create a stunning shock wave (see image below). Each strike can take out up to seven sardines, so Oliver thinks it is probably the most energy-efficient way for the animals to hunt. The team published the results today in PLOS ONE3. © 2013 Nature Publishing Group

Keyword: Intelligence; Evolution
Link ID: 18367 - Posted: 07.11.2013

By Helen Briggs BBC News Today's 90-year-olds are surviving into very old age with better mental performance than ever before, Danish research suggests. People born in 1915 scored higher in cognitive tests in their 90s compared with those born a decade earlier, according to a study in The Lancet. Better living standards and intellectual stimulation may be key factors, experts say. The number of people reaching very old age is on the rise globally. In the US, for example, the amount of people aged 90 or above has more than doubled in 30 years. In Denmark, where the study took place, the chance of surviving into the 10th decade of life has gone up by about 30% each decade for people born in 1895, 1905 and 1915. However, there has been little research on the quality of life that people reaching such an old age can look forward to. The researchers, led by Prof Kaare Christensen, of the University of Southern Denmark in Odense, surveyed all Danes born in 1905 who were still alive and living in the country in 1998 (3,600 people, aged 92-93). They assessed their physical strength, mental functioning, ability to carry out daily living tasks such as walking inside and outside, and any symptoms of depression. BBC © 2013

Keyword: Alzheimers
Link ID: 18366 - Posted: 07.11.2013

by Jessica Hamzelou THE next generation may live to see 100, and with old age inevitably comes illness. While older people may be more prone to getting cancer or Alzheimer's, it seems they are unlikely to succumb to both. Understanding this link could offer insights into treating both diseases. The association was first noticed in 2005 when researchers looked at how many people over 65 with cancer later developed Alzheimer's, and vice versa. To further explore the link, Massimo Musicco at the Institute of Biomedical Technology in Milan, Italy, and his colleagues recorded cancer and Alzheimer's diagnoses for over a million people by looking at registries of drug prescriptions and hospital admissions between 2004 and 2009. In each case of cancer or Alzheimer's, they checked for the other disease before the person was treated, as well as in the years after. The group found that people with Alzheimer's were half as likely to develop cancer as their age-matched peers. People with cancer, on the other hand, were 35 per cent less likely to get Alzheimer's. "It's a very convincing demonstration of the links between two pathologies that we often think of as separate," says Richard Faragher of the British Society for Research on Ageing. "The question is: what is going on?" Although both diseases are linked to ageing, they work in very different ways. While cancer results from the uncontrolled growth of cells, Alzheimer's is related to the death of brain cells. © Copyright Reed Business Information Ltd.

Keyword: Alzheimers
Link ID: 18365 - Posted: 07.11.2013

By Kate Wong In the July issue of Scientific American, anthropologist Barbara King of The College of William & Mary makes the case that animals ranging from ducks to dolphins may grieve when a relative or close companion dies. In so doing she departs from a long-standing tradition among animal behaviorists of assiduously avoiding projecting human emotions onto other animals. Not all animal responses to death qualify as mourning, however. King is careful to establish criteria for grief, noting that “researchers may strongly suspect grief only when certain conditions are met: First, two (or more) animals choose to spend time together beyond survival-oriented behaviors such as foraging or mating. Second, when one animal dies, the survivor alters his or her normal behavioral routine—perhaps reducing the amount of time devoted to eating or sleeping, adopting a body posture or facial expression indicative of depression or agitation, or generally failing to thrive.” Here King describes two recent, well-publicized examples of animal reactions to death that illustrate the challenges of interpreting such behaviors: “Occasionally the pull of anthropomorphism may overwhelm scientists’ normal caution in reporting animal responses to death. When Teresa Iglesias of the University of California at Davis and her colleagues published a paper in Animal Behaviour last year entitled ‘Western scrub jay funerals: cacophonous aggregations in response to dead conspecifics,’ the news media responded enthusiastically to the notion of a bird funeral. Yet nothing like a caretaking ritual around jay bodies actually had been observed. From a series of experiments, the scientists had discovered that scrub jays respond by vocalizing upon sighting the bodies of dead companions; they seem to be communicating information to their flock mates about potential risks in the environment. Iglesias told me last year, for my post about her paper at NPR.org’s 13.7 blog, that ‘funeral’ is an apt term ‘only to the extent that it is an animal paying attention to another dead animal’ (and excluding behaviors such as scavenging). Any of the animal examples discussed in this article would, on this definition, quality as a ‘funeral,’ a too-generous application of the term.” © 2013 Scientific American

Keyword: Emotions; Evolution
Link ID: 18364 - Posted: 07.09.2013

by Kelly Servick It almost seems like a mystical correlation. Babies conceived at certain times of the year appear healthier than those conceived during other times. Now, scientists have shown that the bizarre phenomenon is actually true—and they think they may know why it happens. The work is "a really long-overdue analysis," says economist Douglas Almond of Columbia University, who was not involved in the study. "This is maybe not quite a smoking gun," he says, "but it's much stronger than the previous evidence." As early as the 1930s, researchers noticed that children born in winter were more prone to health problems later in life: slower growth, mental illness, and even early death. Among the proposed explanations were diseases, harsh temperatures, and higher pollution levels associated with winter, when those expectant mothers and near-term fetuses might be most vulnerable. But recently, as economists looked at demographics, the picture got more complicated. Mothers who are nonwhite, unmarried, or lack a college education are more likely to have children with health and developmental problems. They are also more likely to conceive in the first half of the year. That made it hard to tease out the socioeconomic effects from the seasonal ones. Economists Janet Currie and Hannes Schwandt of Princeton University took a new approach to resolving this long-standing question, using data from the vital statistics offices in New Jersey, New York, and Pennsylvania about births between 1994 and 2006. To control for socioeconomic status, their study looked only at siblings born to the same mother. And lo and behold, seasonal patterns persist, they report online today in the Proceedings of the National Academy of Sciences. © 2010 American Association for the Advancement of Science

Keyword: Biological Rhythms; Schizophrenia
Link ID: 18363 - Posted: 07.09.2013

By Michelle Roberts Health editor, BBC News online Late nights and lax bedtime routines can blunt young children's minds, research suggests. The findings on sleep patterns and brain power come from a UK study of more than 11,000 seven-year-olds. Youngsters who had no regular bedtime or who went to bed later than 21:00 had lower scores for reading and maths. Lack of sleep may disrupt natural body rhythms and impair how well the brain learns new information say the study authors. They gathered data on the children at the ages of three, five and then seven to find out how well they were doing with their learning and whether this might be related to their sleeping habits. Erratic bedtimes were most common at the age of three, when around one in five of the children went to bed at varying times. By the age of seven, more than half the children had a regular bedtime of between 19:30 and 20:30. Overall, children who had never had regular bedtimes tended to fare worse than their peers in terms of test scores for reading, maths and spatial awareness. The impact was more obvious throughout early childhood in girls than in boys and appeared to be cumulative. BBC © 2013

Keyword: Sleep; Learning & Memory
Link ID: 18362 - Posted: 07.09.2013

By Darold Treffert The good news is that occasionally one reads about children who have ‘recovered’ from, or who have ‘out-grown’ their ‘autism’. And that’s great. Not to detract anything from that good news, though, if truth be told, the ‘recovery’ in many cases is from autism they fortunately never had. Instead what those children ‘outgrew’ were conditions such as hyperlexia (children who read early) or Einstein Syndrome (children who speak late) in which ‘autistic-like’ symptoms can be, for a period of time, in my view, prematurely and mistakenly misdiagnosed as Autistic Spectrum Disorder. The good news that these non-autistic children turn out to be bright, successful, neurotypical children remains undiminished. But the bad news is that in the meantime parents have been needlessly pessimistic and worried about their child, and sometimes unnecessary or even misguided treatment, educational and other management decisions have been carried out. I have been involved with the study of autism for many years. In fact I had the opportunity to learn about autism directly from Dr. Leo Kanner himself when he was a visiting professor at times during my medical school years. Dr.Kanner was the first to identify and name early infantile autism in 1943. Following my psychiatric residency I started a Children’s Unit at a psychiatric hospital in Wisconsin. Most of the patients were autistic and it was there I also met my first savants that have also so intrigued me and have been the object of my research for over 50 years as documented in my 2010 book on the topic: Islands of Genius: The Bountiful Mind of the Autistic, Acquired and Sudden Savant. © 2013 Scientific American

Keyword: Autism
Link ID: 18361 - Posted: 07.09.2013

By PERRI KLASS, M.D. My patient was missing a lot of middle school because of headaches. Her physical exam was completely normal, and the symptoms sounded like migraine — she had a throbbing sensation on both sides of her head, was more comfortable when the room was dark, and felt much better if she took ibuprofen. I asked her to keep a “headache diary,” noting when the headaches came, how long they lasted, what made them better or worse. Instead, that evening she and her mother went to the emergency room, where a head CT scan was done. The scan was normal, the diagnosis migraine, and mother and daughter felt better. They had been worried the girl might have had a brain tumor. Headaches are common in children, interfering with school, with activities, with life in general. Many children get migraines, even some too young to describe their symptoms: Sometimes they hit themselves in the head in reaction to the pain. Other children get “tension-type” headaches, sometimes related to muscle tightness or to stress. Children’s headaches can be related to ailments, from allergies to ear infections to sinus problems, and most of the time they don’t indicate a dangerous illness. But for many parents, the shadow of a terrible diagnosis lurks in the corner of the darkened room where a headachy child is lying with a cool cloth on her brow. Sometimes, children with headaches need neuroimaging — brain CTs or M.R.I.’s. But recently several large studies have raised concerns about CT scans done on children because the radiation from these scans can increase the risk of eventually developing cancer, though that overall risk is still very small. Copyright 2013 The New York Times Company

Keyword: Pain & Touch
Link ID: 18360 - Posted: 07.09.2013

Research from the National Institutes of Health has identified neural circuits in mice that are involved in the ability to learn and alter behaviors. The findings help to explain the brain processes that govern choice and the ability to adapt behavior based on the end results. Researchers think this might provide insight into patterns of compulsive behavior such as alcoholism and other addictions. “Much remains to be understood about exactly how the brain strikes the balance between learning a behavioral response that is consistently rewarded, versus retaining the flexibility to switch to a new, better response,” said Kenneth R. Warren, Ph.D., acting director of the National Institute on Alcohol Abuse and Alcoholism. “These findings give new insight into the process and how it can go awry.” The study, published online in Nature Neuroscience, indicates that specific circuits in the forebrain play a critical role in choice and adaptive learning. Like other addictions, alcoholism is a disease in which voluntary control of behavior progressively diminishes and unwanted actions eventually become compulsive. It is thought that the normal brain processes involved in completing everyday activities become redirected toward finding and abusing alcohol. Researchers used a simple choice task in which mice viewed images on a computer touchscreen and learned to touch a specific image with their nose to get a food reward. Using various techniques to visualize and record neural activity, researchers found that as the mice learned to consistently make a choice, the brain’s dorsal striatum was activated. The dorsal striatum is thought to play an important role in motivation, decision-making, and reward.

Keyword: Drug Abuse; Learning & Memory
Link ID: 18359 - Posted: 07.09.2013

Meredith Wadman The woman was four months pregnant, but she didn't want another child. In 1962, at a hospital in Sweden, she had a legal abortion. The fetus — female, 20 centimetres long and wrapped in a sterile green cloth — was delivered to the Karolinska Institute in northwest Stockholm. There, the lungs were dissected, packed on ice and dispatched to the airport, where they were loaded onto a transatlantic flight. A few days later, Leonard Hayflick, an ambitious young microbiologist at the Wistar Institute for Anatomy and Biology in Philadelphia, Pennsylvania, unpacked that box. Working with a pair of surgical scalpels, Hayflick minced the lungs — each about the size of an adult fingertip — then placed them in a flask with a mix of enzymes that fragmented them into individual cells. These he transferred into several flat-sided glass bottles, to which he added a nutrient broth. He laid the bottles on their sides in a 37 °C incubation room. The cells began to divide. So began WI-38, a strain of cells that has arguably helped to save more lives than any other created by researchers. Many of the experimental cell lines available at that time, such as the famous HeLa line, had been grown from cancers or were otherwise genetically abnormal. WI-38 cells became the first 'normal' human cells available in virtually unlimited quantities to scientists and to industry and, as a result, have become the most extensively described and studied normal human cells available to this day. © 2013 Nature Publishing Group

Keyword: Stem Cells
Link ID: 18358 - Posted: 07.09.2013

by Debora MacKenzie Starfish use the light-sensitive organs at the tips of their arms to form images, helping the animals find their way home if they stray from the reef. We have known about the sensors that starfish have at the ends of their arms for 200 years, but no one knew whether they are real eyes that form images or simply structures that detect changes in light intensity. We finally have an answer: they appear to act as real eyes. The discovery is another blow to creationist arguments that something as complex as a human eye could never evolve from simpler structures. The blue sea star (Linckia laevigata), which is widely sold as dried souvenirs, lives on shallow rock reefs in the Indian and Pacific oceans. It can detect light, preferring to come out at night to graze on algae. The light sensitivity has recently been found to be due to pigments called opsins, expressed in cells close to the animal's nerve net. What has not been clear, says Anders Garm at the University of Copenhagen in Denmark, is whether these cells simply tell the starfish about ambient light levels, as happens in more primitive light-sensitive animals, or whether they actually form spatial images. © Copyright Reed Business Information Ltd.

Keyword: Vision; Evolution
Link ID: 18357 - Posted: 07.08.2013

By MICHAEL WINERIP PETA, considered by many to be the highest-profile animal rights group in the country, kills an average of about 2,000 dogs and cats each year at its animal shelter here. And the shelter does few adoptions — 19 cats and dogs in 2012 and 24 in 2011, according to state records. At a time when the major animal protection groups have moved to a “no kill” shelter model, People for the Ethical Treatment of Animals remains a holdout, confounding some and incensing others who know the organization as a very vocal advocacy group that does not believe animals should be killed for food, fur coats or leather goods. This is an organization that on Thanksgiving urges Americans not to eat turkey. “Honestly, I don’t understand it,” says Joan E. Schaffner, an animal rights lawyer and an associate professor at the George Washington University Law School, which hosts an annual no-kill conference. “PETA does lots of good for animals, but I could never support them on this.” As recently as a decade ago, it was common practice at shelters to euthanize large numbers of dogs and cats that had not been adopted. But the no-kill movement has grown very quickly, leaving PETA behind. In New York City last year, 8,252 dogs and cats were euthanized, compared with 31,701 in 2003. “Through spay, neuter, transfer and adoption programs, we think New York City can close the gap toward becoming a ‘no-kill community’ by 2015,” said Matthew Bershadker, the president and chief executive of the American Society for the Prevention of Cruelty to Animals, one of 150 rescue groups and shelters that make up the Mayor’s Alliance for N.Y.C.’s Animals. © 2013 The New York Times Company

Keyword: Animal Rights
Link ID: 18356 - Posted: 07.08.2013

By Emma Tracey BBC News, Ouch An online magazine for the deaf community, Limping Chicken, recently ran an item on how deaf and hearing people sneeze differently. The article by partially deaf journalist Charlie Swinbourne got readers talking - and the cogs started turning at Ouch too. Swinbourne observes that deaf people don't make the "achoo!" sound when they sneeze, while hearing people seem to do it all the time - in fact, he put it in his humorous list, The Top 10 Annoying Habits of Hearing People. Nor is "achoo" universal - it's what English-speaking sneezers say. The French sneeze "atchoum". In Japan, it's "hakashun" and in the Philippines, they say "ha-ching". Inserting words into sneezes - and our responses such as "bless you" - are cultural habits we pick up along the way. So it's not surprising that British deaf people, particularly users of sign language, don't think to add the English word "achoo" to this most natural of actions. For deaf people, "a sneeze is what it should be... something that just happens", says Swinbourne in his article. He even attempts to describe what an achoo-free deaf sneeze sounds like: "[There is] a heavy breath as the deep pre-sneeze breath is taken, then a sharper, faster sound of air being released." Very little deaf-sneeze research exists, but a study has been done on deaf people and their laughter. BBC © 2013

Keyword: Hearing
Link ID: 18355 - Posted: 07.08.2013

Melatonin is marketed as a natural sleep aid but it's potentially risky for healthy children to use long term, Canadian pediatricians say. Difficulties settling, falling asleep and staying asleep affect up to 25 per cent of children generally and up to half of those with physical and mental health problems, according to the Canadian Sleep Society. Melatonin is a hormone of darkness that is part of the sleep cycle. People can buy melatonin supplements at pharmacies and health food stores to overcome jet lag or occasional insomnia. But long-term use by healthy, developing children isn't advised, said Dr. Shelly Weiss, a neurologist at the Hospital for Sick Children in Toronto, who is studying the use of melatonin supplements for improving sleep in children with epilepsy. "It's being touted as this magic pill," said Weiss. "There's definitely concern that people are going to use it more widely and not appreciate that their child can learn to sleep better without a hormone being given." Melatonin supplements contain between 25 to 50 times as much melatonin as the body makes at night, Weiss noted. "There's definitely potential risk, mostly to delayed puberty or delayed development in children who have taken it for a long time," said Weiss, who is also president of the Canadian Sleep Society and an associate professor at the University of Toronto. © CBC 2013

Keyword: Sleep; Hormones & Behavior
Link ID: 18354 - Posted: 07.08.2013

By Jessica Wright and SFARI.org With the right incentive, such as winning a prize, children with autism do fairly well at inferring the thoughts and beliefs of others, according to a study published in the May issue of Developmental Science. Research has shown that children with autism usually struggle with a widely used test designed to gauge this ability, called theory of mind. The new study suggests that they are able to grasp theory of mind, but don’t have a strong motivation to give the correct answer when taking the classic test. The particulars of the test vary, but children are generally told a story in which two characters (often called Sally and Ann) place an object in a basket. After Sally leaves the room, Ann moves the item into a box. The child passes the test if he or she knows that Sally will look for the item in the basket and not the box. Typical children struggle with this test as 3-year-olds, but most pass it by 5 years of age. The majority of children with autism continue to fail the test well into their teenage years. Adults with autism are usually able to pass the Sally-Ann test, as it is often called, but struggle with more subtle examples of theory of mind. In the new study, the researchers revised the Sally-Ann test into a game. For typically developing children, the motivation to answer a question correctly may be tied to a desire for social interactions. In contrast, children with autism may use theory of mind when they want something concrete, for example when competing for things with a sibling, the researchers say. © 2013 Scientific American,

Keyword: Autism; Learning & Memory
Link ID: 18353 - Posted: 07.06.2013

by Sara Reardon As a baby's brain rewires itself to face the world ahead, its DNA is rewiring itself at the same time. New maps of chemical modifications to brain DNA have revealed massive epigenetic changes during the first few years of life. Environmental stressors that disrupt the process during this crucial period could lead to mental disorders. During development in mammals, chemical tags called methyl groups are added to certain cytosine nucleotides in the DNA, which affects how nearby genes are expressed. Later, environmental stressors such as stress, diet and disease can alter these patterns and change the genes' expression. These epigenetic modifications appear to play a role in some neurological disorders. For instance, one recent study found that in genetically identical twin pairs in which only one twin has autism, genes involved in brain development have different epigenetic patterns. Because epigenetic patterns can differ between tissues in the body, Ryan Lister of the University of Western Australia in Crawley and colleagues decided to zero in on the brain's methylation. They collected nine human brains including examples from fetuses, two-month-old babies, toddlers, teenagers and older adults, and the same from mice at equivalent stages of development. © Copyright Reed Business Information Ltd.

Keyword: Development of the Brain; Neurogenesis
Link ID: 18352 - Posted: 07.06.2013