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Mice with a condition that serves as a laboratory model for Down syndrome perform better on memory and learning tasks as adults if they were treated before birth with neuroprotective peptides, according to researchers at the National Institutes of Health. Down syndrome results when an individual receives an extra copy of chromosome 21. According to the Centers for Disease Control and Prevention, Down syndrome occurs in 1 of every 691 births. Features of Down syndrome include delays in mental and physical development and poor muscle tone. These features may vary greatly, ranging from mild to severe. The researchers studied growth factors that are important at certain key stages of brain development in the womb. Named for the first three amino acids making up their chemical sequence, NAP and SAL, are small peptides (small protein sub units) of two proteins. These two proteins enhance the ability of brain cells to receive and transmit signals, and enable them to survive. (NAP is an abbreviation for NAPVSIPQ and SALfor SALLRSIPA.) The mice in the study had an extra copy of mouse chromosome 16, which has mouse counterparts to 55 percent of the genes on human chromosome 21.The researchers treated pregnant mice with NAP and SAL for five days, then tested the mouse offspring at 8 to 12 months of age, comparing them to mice treated with a saline solution (placebo). Mice with the extra chromosomal material that were treated with NAP and SAL in the womb learned as well as mice that did not have the extra chromosome, and significantly faster than mice with the extra chromosome that were treated with saline solution.

Related chapters from BP7e: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory, Learning, and Development
Link ID: 17555 - Posted: 12.01.2012

By NICHOLAS BAKALAR Everyone yawns. And we start yawning even before we are born. Now, using ultrasound video recordings, researchers have worked out a technique to distinguish prenatal yawns from the simple mouth openings that we also engage in well before birth. For the study, published on Wednesday in PLoS One, scientists scanned 15 healthy fetuses, eight girls and seven boys, at 24, 28, 32 and 36 weeks’ gestation. They distinguished yawns from jaw openings by the timing of the action and shape of the fetuses’ mouths. In all, they counted 56 yawns and 27 non-yawn mouth openings. By 36 weeks, the yawning had completely disappeared. Why fetuses yawn is unclear — for that matter, it is unclear why adults yawn. In any case, the study’s lead author, Nadja Reissland, a developmental psychologist at Durham University in England, said that yawning in a fetus is different from yawning in adults. “When you see a fetus yawning, it’s not because it’s tired,” she said. “The yawning itself might have some kind of function in healthy development. Fetuses yawn, and then as they develop they stop yawning. There’s something special in yawning.” Copyright 2012 The New York Times Company

Related chapters from BP7e: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 13: Memory, Learning, and Development; Chapter 10: Biological Rhythms and Sleep
Link ID: 17529 - Posted: 11.24.2012

By Laura Beil Kotex, the company that first capitalized on the concept of “feminine hygiene” more than 90 years ago, recently gained newfound success after it began targeting an underserved market: girls who start their periods before they start middle school. With hearts, swirls and sparkles, the U brand offers maxi pads and tampons for — OMG! — girls as young as 8, promoted through a neon-hued website with chatty girl-to-girl messages and breezy videos. “When I had my first period I was prepared,” reads one testimonial. “It was the summer before 4th grade….” Today it has become common for girls to enter puberty before discovering Are You There God? It’s Me, Margaret. Over the second half of the 20th century, the average age for girls to begin breast development has dropped by a year or more in the industrialized world. And the age of first menstruation, generally around 12, has advanced by a matter of months. Hispanic and black girls may be experiencing an age shift much more pronounced. The idea of an entire generation maturing faster once had a strong cadre of doubters. In fact, after one of the first studies to warn of earlier puberty in American girls was published in 1997, skeptics complained in the journal Pediatrics that “many of us in the field of pediatric endocrinology believe that it is premature to conclude that the normal age of puberty is occurring earlier.” Today, more than 15 years later, a majority of doctors appear to have come around to the idea. Have a conversation with a pediatric endocrinologist, and it isn’t long before you hear the phrase “new normal.” © Society for Science & the Public 2000 - 2012

Related chapters from BP7e: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 5: Hormones and the Brain
Related chapters from MM:Chapter 13: Memory, Learning, and Development; Chapter 8: Hormones and Sex
Link ID: 17503 - Posted: 11.19.2012

David Cyranoski In December 2010, Robin Ali became suddenly excited by the usually mundane task of reviewing a scientific paper. “I was running around my room, waving the manuscript,” he recalls. The paper described how a clump of embryonic stem cells had grown into a rounded goblet of retinal tissue. The structure, called an optic cup, forms the back of the eye in a growing embryo. But this one was in a dish, and videos accompanying the paper showed the structure slowly sprouting and blossoming. For Ali, an ophthalmologist at University College London who has devoted two decades to repairing vision, the implications were immediate. “It was clear to me it was a landmark paper,” he says. “He has transformed the field.” 'He' is Yoshiki Sasai, a stem-cell biologist at the RIKEN Center for Developmental Biology in Kobe, Japan. Sasai has impressed many researchers with his green-fingered talent for coaxing neural stem cells to grow into elaborate structures. As well as the optic cup1, he has cultivated the delicate tissue layers of the cerebral cortex2 and a rudimentary, hormone-making pituitary gland3. He is now well on the way to growing a cerebellum4 — the brain structure that coordinates movement and balance. “These papers make for the most addictive series of stem-cell papers in recent years,” says Luc Leyns, a stem-cell scientist at the Free University of Brussels. Sasai's work is more than tissue engineering: it tackles questions that have puzzled developmental biologists for decades. How do the proliferating stem cells of an embryo organize themselves seamlessly into the complex structures of the body and brain? And is tissue formation driven by a genetic program intrinsic to cells, or shaped by external cues from neighbouring tissues? © 2012 Nature Publishing Group

Related chapters from BP7e: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 13: Memory, Learning, and Development; Chapter 7: Vision: From Eye to Brain
Link ID: 17480 - Posted: 11.13.2012

By ANDREW SOLOMON Drew Petersen didn’t speak until he was 3½, but his mother, Sue, never believed he was slow. When he was 18 months old, in 1994, she was reading to him and skipped a word, whereupon Drew reached over and pointed to the missing word on the page. Drew didn’t produce much sound at that stage, but he already cared about it deeply. “Church bells would elicit a big response,” Sue told me. “Birdsong would stop him in his tracks.” Sue, who learned piano as a child, taught Drew the basics on an old upright, and he became fascinated by sheet music. “He needed to decode it,” Sue said. “So I had to recall what little I remembered, which was the treble clef.” As Drew told me, “It was like learning 13 letters of the alphabet and then trying to read books.” He figured out the bass clef on his own, and when he began formal lessons at 5, his teacher said he could skip the first six months’ worth of material. Within the year, Drew was performing Beethoven sonatas at the recital hall at Carnegie Hall. “I thought it was delightful,” Sue said, “but I also thought we shouldn’t take it too seriously. He was just a little boy.” On his way to kindergarten one day, Drew asked his mother, “Can I just stay home so I can learn something?” Sue was at a loss. “He was reading textbooks this big, and they’re in class holding up a blowup M,” she said. Drew, who is now 18, said: “At first, it felt lonely. Then you accept that, yes, you’re different from everyone else, but people will be your friends anyway.” Drew’s parents moved him to a private school. They bought him a new piano, because he announced at 7 that their upright lacked dynamic contrast. “It cost more money than we’d ever paid for anything except a down payment on a house,” Sue said. When Drew was 14, he discovered a home-school program created by Harvard; when I met him two years ago, he was 16, studying at the Manhattan School of Music and halfway to a Harvard bachelor’s degree. © 2012 The New York Times Company

Related chapters from BP7e: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 13: Memory, Learning, and Development; Chapter 14: Attention and Consciousness
Link ID: 17454 - Posted: 11.05.2012

by Ann Gibbons Eating a raw food diet is a recipe for disaster if you're trying to boost your species' brainpower. That's because humans would have to spend more than 9 hours a day eating to get enough energy from unprocessed raw food alone to support our large brains, according to a new study that calculates the energetic costs of growing a bigger brain or body in primates. But our ancestors managed to get enough energy to grow brains that have three times as many neurons as those in apes such as gorillas, chimpanzees, and orangutans. How did they do it? They got cooking, according to a study published online today in the Proceedings of the National Academy of Sciences. "If you eat only raw food, there are not enough hours in the day to get enough calories to build such a large brain," says Suzana Herculano-Houzel, a neuroscientist at the Federal University of Rio de Janeiro in Brazil who is co-author of the report. "We can afford more neurons, thanks to cooking." Humans have more brain neurons than any other primate—about 86 billion, on average, compared with about 33 billion neurons in gorillas and 28 billion in chimpanzees. While these extra neurons endow us with many benefits, they come at a price—our brains consume 20% of our body's energy when resting, compared with 9% in other primates. So a long-standing riddle has been where did our ancestors get that extra energy to expand their minds as they evolved from animals with brains and bodies the size of chimpanzees? © 2010 American Association for the Advancement of Science.

Related chapters from BP7e: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory, Learning, and Development
Link ID: 17408 - Posted: 10.23.2012

Researchers in the U.S. have found signs of puberty in American boys up to two years earlier than previously reported — age nine on average for blacks, 10 for whites and Hispanics. Other studies have suggested that girls, too, are entering puberty younger. Why is this happening? Theories range from higher levels of obesity and inactivity to chemicals in food and water, all of which might interfere with normal hormone production. But those are just theories, and they remain unproven. Doctors say earlier puberty is not necessarily cause for concern. And some experts question whether the trend is even real. Boys are more likely than girls to have an underlying physical cause for early puberty.Boys are more likely than girls to have an underlying physical cause for early puberty. (Jennifer DeMonte/Associated Press) Dr. William Adelman, an adolescent medicine specialist in the Baltimore area, says the new research is the first to find early, strong physical evidence that boys are maturing earlier. But he added that the study still isn't proof and said it raises a lot of questions. Earlier research based on 20-year-old national data also suggested a trend toward early puberty in boys, but it was based on less rigorous information. The new study involved testes measurements in more than 4,000 boys. Enlargement of testes is generally the earliest sign of puberty in boys. The study was published online Saturday in Pediatrics to coincide with the American Academy of Pediatrics' national conference in New Orleans. © CBC 2012

Related chapters from BP7e: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 5: Hormones and the Brain
Related chapters from MM:Chapter 13: Memory, Learning, and Development; Chapter 8: Hormones and Sex
Link ID: 17401 - Posted: 10.22.2012

by Helen Thomson, New Orleans HUMANS are constantly searching for an elixir of youth - could it be that an infusion of young blood holds the key? This seems to be true for mice, at least. According to research presented this week at the Society for Neuroscience conference in New Orleans, Louisiana, giving young blood to old mice can reverse some of the effects of age-related cognitive decline. Last year, Saul Villeda, then at Stanford University in California, and colleagues showed they could boost the growth of new cells in the brains of old mice by giving them a blood infusion from young mice (Nature, doi.org/c9jwvm). "We know that blood has this huge effect on brain cells, but we didn't know if its effects extended beyond cell regeneration," he says. Now the team has tested for changes in cognition by linking the circulatory systems of young and old mice. Once the blood of each conjoined mouse had fully mixed with the other, the researchers analysed their brains. Tissue from the hippocampus of old mice given young blood showed changes in the expression of 200 to 300 genes, particularly in those involved in synaptic plasticity, which underpins learning and memory. They also found changes in some proteins involved in nerve growth. The infusion of young blood also boosted the number and strength of neuronal connections in an area of the brain where new cells do not grow. This didn't happen when old mice received old blood. © Copyright Reed Business Information Ltd.

Related chapters from BP7e: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 17: Learning and Memory
Related chapters from MM:Chapter 13: Memory, Learning, and Development; Chapter 13: Memory, Learning, and Development
Link ID: 17385 - Posted: 10.18.2012

Nearly a quarter of seniors said they'd like to participate in more social activities, according to a new report by Statistics Canada. The agency released the first nationally representative study on barriers to social participation by seniors on Wednesday. "Social engagement — involvement in meaningful activities and maintaining close relationships — is a component of successful aging," wrote Heather Gilmour of Statistics Canada's health analysis division. "The results of this analysis highlight the importance of frequent social participation to maintaining quality of life." Overall, an estimated 80 per cent said they were frequent participants in at least one social activity, such as seeing relatives or friends outside the household, attending church or religious activities like a choir or sports at least weekly or attending concerts or volunteering at least monthly. "The greater the number of frequent social activities, the higher the odds of positive self-perceived health, and the lower the odds of loneliness and life dissatisfaction," Gilmour said. "This is consistent with research that has found seniors with a wider range of social ties have better well-being." © CBC 2012

Related chapters from BP7e: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory, Learning, and Development
Link ID: 17384 - Posted: 10.18.2012

by Moheb Costandi NEW ORLEANS, LOUISIANA—Books and educational toys can make a child smarter, but they also influence how the brain grows, according to new research presented here on Sunday at the annual meeting of the Society for Neuroscience. The findings point to a "sensitive period" early in life during which the developing brain is strongly influenced by environmental factors. Studies comparing identical and nonidentical twins show that genes play an important role in the development of the cerebral cortex, the thin, folded structure that supports higher mental functions. But less is known about how early life experiences influence how the cortex grows. To investigate, neuroscientist Martha Farah of the University of Pennsylvania and her colleagues recruited 64 children from a low income background and followed them from birth through to late adolescence. They visited the children's homes at 4 and 8 years of age to evaluate their environment, noting factors such as the number of books and educational toys in their houses, and how much warmth and support they received from their parents. More than 10 years after the second home visit, the researchers used MRI to obtain detailed images of the participants' brains. They found that the level of mental stimulation a child receives in the home at age 4 predicted the thickness of two regions of the cortex in late adolescence, such that more stimulation was associated with a thinner cortex. One region, the lateral inferior temporal gyrus, is involved in complex visual skills such as word recognition. © 2010 American Association for the Advancement of Science

Related chapters from BP7e: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 19: Language and Hemispheric Asymmetry
Related chapters from MM:Chapter 13: Memory, Learning, and Development; Chapter 15: Language and Our Divided Brain
Link ID: 17382 - Posted: 10.18.2012

By Jason G. Goldman Television has a bad side. According to a report from the University of Michigan, the average American child has seen sixteen thousand murders on TV by age 18. Indeed, programs explicitly designed for kids often contain more violence than adult programming, and that violence is often paired with humor. Every single animated feature film produced by US production houses between 1937 and 1999 contained violence, and the amount of violence increased throughout that time period. Researchers from the University of Michigan found that just being awake and in the room with a TV on more than two hours a day – even if the kids aren’t explicitly paying attention to the TV – was a risk factor for being overweight at ages three and four-and-a-half. This may be related to the fact that two thirds of the twenty thousand television commercials the average child sees each year are for food. The American Academy of Pediatrics, in their wisdom, recommend that children under age two have zero hours of screen time. (Meanwhile, a bevy of DVDs are marketed to parents of children age zero to 2, promising to “teach your child about language and logic, patterns and sequencing, analyzing details and more.”) Despite the warning, however, many parents of infants age 0 to 2 do allow their children some screen time. In 2007, Frederick J. Zimmerman of the University of Washington (now at UCLA) wondered what the effects of TV watching were on those infants. He collected data from 1008 parents about the infants’ TV habits, as well as the amount of time they spent doing things like reading (with parents), playing, and so on. He also administered, for each child, a survey called the MacArthur-Bates Communicative Development Inventory (CDI). The CDI is a standard tool used by developmental psychologists to assess language development in infants and children. He and his team then looked to see if there were statistical relationships between time spent watching TV (and the other activities) and language abilities, as measured by the CDI. Here’s the catch: they only included infants whose TV watching consisted entirely of infant-directed programming. That is, TV programs especially designed for infants age 0 to 2. If the infants were shown other sorts of TV programs, they were not included in the study. © 2012 Scientific American,

Related chapters from BP7e: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory, Learning, and Development
Link ID: 17373 - Posted: 10.16.2012

By Ferris Jabr In the 1970s biologist Sydney Brenner and his colleagues began preserving tiny hermaphroditic roundworms known as Caenorhabditis elegans in agar and osmium fixative, slicing up their bodies like pepperoni and photographing their cells through a powerful electron microscope. The goal was to create a wiring diagram—a map of all 302 neurons in the C. elegans nervous system as well as all the 7,000 connections, or synapses, between those neurons. In 1986 the scientists published a near complete draft of the diagram. More than 20 years later, Dmitri Chklovskii of Janelia Farm Research Campus and his collaborators published an even more comprehensive version. Today, scientists call such diagrams "connectomes." So far, C. elegans is the only organism that boasts a complete connectome. Researchers are also working on connectomes for the fruit fly nervous system and the mouse brain. In recent years some neuroscientists have proposed creating a connectome for the entire human brain—or at least big chunks of it. Perhaps the most famous proponent of connectomics is Sebastian Seung of the Massachusetts Institute of Technology, whose impressive credentials, TED talk, popular book, charisma and distinctive fashion sense (he is known to wear gold sneakers) have made him a veritable neuroscience rock star. Other neuroscientists think that connectomics at such a large scale—the human brain contains around 86 billion neurons and 100 trillion synapses—is not the best use of limited resources. It would take far too long to produce such a massive map, they argue, and, even if we had one, we would not really know how to interpret it. To bolster their argument, some critics point out that the C. elegans connectome has not provided many insights into the worm's behavior. In a debate* with Seung at Columbia University earlier this year, Anthony Movshon of New York University said, "I think it's fair to say…that our understanding of the worm has not been materially enhanced by having that connectome available to us. We don't have a comprehensive model of how the worm's nervous system actually produces the behaviors. What we have is a sort of a bed on which we can build experiments—and many people have built many elegant experiments on that bed. But that connectome by itself has not explained anything." © 2012 Scientific American

Related chapters from BP7e: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior
Related chapters from MM:Chapter 13: Memory, Learning, and Development; Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 17325 - Posted: 10.03.2012

By Simon J Makin Humans are born to a longer period of total dependence than any other animal we know of, and we also know that mistreatment or neglect during this time often leads to social, emotional, cognitive and mental health problems in later life. It’s not hard to imagine how a lack of proper stimulation in our earliest years – everything from rich sensory experiences and language exposure to love and care – might adversely affect our development, but scientists have only recently started to pull back the curtain on the genetic, molecular and cellular mechanisms that might explain how these effects arise in the brain. You’ll often hear it said that human beings are “social animals”. What biologists tend to mean by that phrase is behaviour like long-lasting relationships or some kind society, whether that’s the social hierarchy of gorillas or the extreme organisation of bees and ants. But, to an extent, most animals are social. A mother usually bonds with its offspring in any species of bird or mammal you care to mention, and almost all animals indulge in some kind of social behaviour when they mate. But there is another sense in which most animals seem to be fundamentally social. There is an emerging scientific understanding of the way social experience moulds the biochemistry of the brain and it looks like most species don’t just prefer the company of others – they need it to develop properly. Take that staple of genetics research, drosophila – aka the fruit fly. While they are not as social as primates or bees, they are more social than you might think, and there have been studies showing that social isolation can disrupt their mating behaviour or even reduce their lifespan. © 2012 Scientific American,

Related chapters from BP7e: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior
Related chapters from MM:Chapter 1: An Introduction to Brain and Behavior
Link ID: 17318 - Posted: 10.02.2012

by Melissa Lee Phillips Giving a whole new meaning to "pregnancy brain," a new study shows that male DNA—likely left over from pregnancy with a male fetus—can persist in a woman's brain throughout her life. Although the biological impact of this foreign DNA is unclear, the study also found that women with more male DNA in their brains were less likely to have suffered from Alzheimer's disease—hinting that the male DNA could help protect the mothers from the disease, the researchers say. During mammalian pregnancy, the mother and fetus exchange DNA and cells. Previous work has shown that fetal cells can linger in the mother's blood and bone for decades, a condition researchers call fetal microchimerism. The lingering of the fetal DNA, research suggests, may be a mixed blessing for a mom: The cells may benefit the mother's health—by promoting tissue repair and improving the immune system—but may also cause adverse effects, such as autoimmune reactions. One question is how leftover fetal cells affect the brain. Researchers have shown that fetal microchimerism occurs in mouse brains, but they had not shown this in humans. So a team led by autoimmunity researcher and rheumatologist J. Lee Nelson of the Fred Hutchinson Cancer Research Center in Seattle, Washington, took samples from autopsied brains of 59 women who died between the ages of 32 and 101. By testing for a gene specific to the Y chromosome, they found evidence of male DNA in the brains of 63% of the women. (The researchers did not have the history of the women's pregnancies.) The male DNA was scattered across multiple brain regions, the team reports online today in PLoS ONE. © 2010 American Association for the Advancement of Science

Related chapters from BP7e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 13: Memory, Learning, and Development
Link ID: 17310 - Posted: 09.27.2012

FRANK JORDANS, Associated Press BERLIN (AP) — More than half the cases of severe intellectual disability caused by genetic defects are the result of random mutations, not inherited, a European study published Thursday suggests. The findings of the small-scale study give hope to parents of children born with a severe intellectual disabilities who are worried about having another baby with the same condition, said Anita Rauch, a researcher at the Institute of Medical Genetics in Zurich who was one of the study's lead authors. It examined the genetic makeup of 51 children, both of their parents and a control group. The study concluded that in at least 55 percent of cases there was no evidence that parents carried faulty genes responsible for the disability. "The average chances of having another child with the same disability are usually estimated at eight percent, but if we know that it was caused by a random mutation the chances of recurrence drop dramatically," Rauch said. Hans-Hilger Ropers, the director of Berlin's Max Planck Institute for Molecular Genetics, who was not involved in the study, said the basic science appeared sound but noted that it excluded children whose parents were blood relatives and so the results could be biased toward random mutations. Ropers said a larger study that included subjects from parts of the world where marriage between blood relatives is more common could produce different results. © 2012 Hearst Communications Inc.

Related chapters from BP7e: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory, Learning, and Development
Link ID: 17308 - Posted: 09.27.2012

Analysis by Tracy Staedter From the department of "I hope this never happens to me," scientists have used a laser to manipulate the behavior of a worm. First, a research team from the Howard Hughes Medical Institute genetically engineered a tiny, transparent worm called Caenorhabditis elegans to have neurons that give off fluorescent light. This allowed the neurons to be tracked during experiments. The scientists also engineered the neurons to be sensitive to light, which made it possible to activate them with pulses of laser light. Next, they built a movable table for the worm to crawl on, keeping it aligned beneath a camera and laser. They used the laser to activate a single neuron at a time. By doing so, they were able to control a worm's behavior and its senses. In tests, which the researchers published in the journal Nature, the laser made the worm turn left or right and move through a loop. The laser also tricked the worm brain into thinking food was nearby. The worm, in turn, wiggled toward what it thought was a meal. The research, which on the surface seems like a bit of a circus, actually is important because it shows scientists which neurons are responsible for what. "If we can understand simple nervous systems to the point of completely controlling them, then it may be a possibility that we can gain a comprehensive understanding of more complex systems," said Sharad Ramanathan, an Assistant Professor of Molecular and Cellular Biology, and of Applied Physics. "This gives us a framework to think about neural circuits, how to manipulate them, which circuit to manipulate and what activity patterns to produce in them." © 2012 Discovery Communications, LLC

Related chapters from BP7e: Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals; Chapter 13: Memory, Learning, and Development
Link ID: 17299 - Posted: 09.26.2012

by Emily Underwood A human newborn's brain is uniquely impressionable, allowing social interactions and the environment to shape its development. But this malleability may come with a price, a new study finds. A comparison of juvenile chimpanzee and human brains suggests that differences in the development of myelin—the fatty sheath that surrounds nerve fibers—may contribute not only to our unusual adaptability, but also to our vulnerability to psychiatric diseases that start in early adulthood. Research increasingly suggests that psychiatric illnesses like depression and schizophrenia may involve problems with the timing of neural signals, says Douglas Fields, a neuroscientist at the National Institutes of Health in Bethesda, Maryland, who was not involved in the study. The nerve fibers, or axons, that connect neurons are usually protected by myelin, which enhances the neural relay of information throughout the brain. "Myelin speeds transmission of information [by] at least 50 times," Fields says, "so it matters a great deal whether or not an axon becomes myelinated." Humans start out with comparatively few myelinated axons as newborns. We experience a burst of myelin development during infancy that is followed by a long, slow growth of myelin that can last into our thirties, says Chet Sherwood, a neuroscientist at George Washington University in Washington, D.C., and a co-author of the new study. In contrast, other primates, such as macaques, start out with significantly more myelin at birth, but stop producing it by the time they reach sexual maturity. However, Sherwood says, "extraordinarily little data exists" on brain growth and the development of myelin in our closest genetic relatives, chimpanzees. © 2010 American Association for the Advancement of Science.

Related chapters from BP7e: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory, Learning, and Development
Link ID: 17295 - Posted: 09.25.2012

Sandrine Ceurstemont, editor, New Scientist TV Chimps may be similar to us in many ways but they can't compete when it comes to brain size. Now for the first time we can see when the differences emerge by tracking the brain development of unborn chimps. As seen in this video, Tomoko Sakai and colleagues from Kyoto University in Japan subjected a pregnant chimp to a 3D ultrasound to gather images of the fetus between 14 and 34 weeks of development. The volume of its growing brain was then compared to that of an unborn human. The team found that brain size increases in both chimps and humans until about 22 weeks, but after then only the growth of human brains continues to accelerate. This suggests that as the brain of modern humans rapidly evolved, differences between the two species emerged before birth as well as afterwards. The researchers now plan to examine how different parts of the brain develop in the womb, particularly the forebrain, which is responsible for decision-making, self-awareness and creativity. If you enjoyed this post, watch the first video MRI of unborn twins or the first MRI movie of a baby's birth. © Copyright Reed Business Information Ltd.

Related chapters from BP7e: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory, Learning, and Development
Link ID: 17293 - Posted: 09.25.2012

by Michael Marshall The human brain may be the most complex object in the universe, but its construction mostly depends on one thing: the shape of neurons. Different kinds of neuron are selective about which other neurons they connect to and where they attach. Specific signalling chemicals are thought to be vital in guiding this process. Henry Markram of the Swiss Federal Institute of Technology in Lausanne and colleagues built 3D computer models of the rat somatosensory cortex, each containing a random mix of cell types found in rat brains, but no signalling chemicals. Nevertheless, 74 per cent of the connections ended up in the correct place, merely by allowing the cells to develop into their normal shape. The results suggest that much of the brain could be mapped without incorporating signalling chemicals. This is good news for neuroscientists struggling to map the brain's dizzying web of connections. "It would otherwise take decades to map each synapse in the brain," says Markram. The work could also help untangle the causes of conditions like schizophrenia that are thought to be caused by flaws in brain wiring. If Markram's work proves correct, malformed neurons that don't connect up properly could be a factor. Journal reference: Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.1202128109 © Copyright Reed Business Information Ltd.

Related chapters from BP7e: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory, Learning, and Development
Link ID: 17267 - Posted: 09.18.2012

By Ingrid Wickelgren In a room tucked next to the reception desk in a colorful lobby of a Park Avenue office tower, kids slide into the core of a white cylinder and practice something kids typically find quite difficult: staying still. Inside the tunnel, a child lies on her back and looks up at a television screen, watching a cartoon. If her head moves, the screen goes blank, motivating her to remain motionless. This dress rehearsal, performed at The Child Mind Institute, prepares children emotionally and physically to enter a real magnet for a scan of their brain. The scan is not part of the child’s treatment; it is his or her contribution to science. What scientists learn from hundreds to thousands of brain scans from children who are ill, as well as those who are not, is likely to be of enormous benefit to children in the future. The Child Mind Institute is a one-of-a-kind facility dedicated to the mental health of children. Its clinicians offer state-of-the-art treatments for children with psychiatric disorders. (For more on its clinical services see my previous post, “Minding Our Children’s Minds.”) In addition to spotting and treating mental illness, The Child Mind Institute is dedicated to improving both through science. Its researchers are helping build a repository of brain scans to better understand both ordinary brain development and how mental illness might warp that process. Tracking the developmental trajectory of mental illness is a critical, overlooked enterprise. Almost three quarters of psychiatric disorders start before age 24 and psychological problems in childhood often portend bona fide, or more severe, diagnoses in adults. If scientists can pinpoint changes that forecast a mental disorder, they might be able to diagnose an incipient disease, when it might be preventable, and possibly target the troublesome circuits through therapy. Certain brain signatures might also provide information about disease risk and prognosis, and about what types of treatments might work best for an individual. © 2012 Scientific American

Related chapters from BP7e: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 13: Memory, Learning, and Development; Chapter 12: Psychopathology: Biological Basis of Behavioral Disorders
Link ID: 17253 - Posted: 09.13.2012