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By Laura Sanders Before you can run, you have to walk, and before you can walk well, you have to walk like a brand-new baby. A new study uncovers the logistics of newborns’ herky-jerky, Frankensteinian stepping action and how this early reflex morphs into refined adult locomotion. In the study, electrodes on infants’ chubby legs picked up signals from neurons that tell muscles to fire, revealing that three-day old babies tense up many of their leg muscles all at once. Toddlers, preschoolers and adults, by contrast, showed a progressively more sophisticated, selective pattern of neuron activity. From birth to adulthood, motor neurons in the spine get an overhaul as neurons in different locations along the spine become specialized for various aspects of walking, such as foot position, balance and direction, Yuri Ivanenko of the Santa Lucia Foundation in Rome and colleagues conclude in the Feb. 13 Journal of Neuroscience. © Society for Science & the Public 2000 - 2013

Related chapters from BP7e: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 13: Memory, Learning, and Development; Chapter 5: The Sensorimotor System
Link ID: 17802 - Posted: 02.14.2013

by Douglas Heaven The learning difficulties that can result from premature birth may not be inevitable. That's the exciting conclusion of two independent but complementary studies. Together, the studies suggest that the relatively small cerebral cortex seen in many preterm babies contains a normal number of neurons despite its size – and that these neurons could be nurtured back to health with the right postnatal care. "For decades we thought of survivors of preterm birth as having a devastating permanent injury," says Stephen Back at the Oregon Health & Science University in Portland. The small cerebral cortex was widely assumed to reflect insufficient neurons in this part of the brain, perhaps because some of the cells are lost following the ischemia – reduced blood flow to brain tissue – often experienced by premature babies. Back and colleagues decided to look at the effects of ischemia on the developing cortex in more detail. To do so they used a fetal sheep brain, as this animal model has been shown to closely match the brain of human fetuses. In a "painstaking but very accurate" process, Back's team used microscopy techniques to count the number of neurons in samples taken from fetal sheep brains that had suffered induced ischemic injury and those that had not. Though the injured cortices had a smaller volume, Back's team was surprised to find that they had the same number of cells as uninjured cortices. "We counted the money and it was all there," says Back. "But the cells were all squished together." Neuron 'saplings' © 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: 17698 - Posted: 01.19.2013

By Rita Levi-Montalcini and Pietro Calissano The human nervous system is a vast network of several billion neurons, or nerve cells, endowed with the remarkable ability to receive, store and transmit information. In order to communicate with one another and with non-neuronal cells the neurons rely on the long extensions called axons, which are somewhat analogous to electrically conducting wires. Unlike wires, however, the axons are fluid-filled cylindrical structures that not only transmit electrical signals but also ferry nutrients and other essential substances to and from the cell body. Many basic questions remain to be answered about the mechanisms governing the formation of this intricate cellular network. How do the nerve cells differentiate into thousands of different types? How do their axons establish specific connections (synapses) with other neurons and non-neuronal cells? And what is the nature of the chemical messages neurons send and receive once the synaptic connections are made? This article will describe some major characteristics and effects of a protein called the nerve-growth factor (NGF), which has made it possible to induce and analyze under highly favorable conditions some crucial steps in the differentiation of neurons, such as the growth and maturation of axons and the synthesis and release of neurotransmitters: the bearers of the chemical messages. The discovery of NGF has also promoted an intensive search for other specific growth factors, leading to the isolation and characterization of a number of proteins with the ability to enhance the growth of different cell lines. © 2013 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: 17652 - Posted: 01.05.2013

By Robert Martone The link between a mother and child is profound, and new research suggests a physical connection even deeper than anyone thought. The profound psychological and physical bonds shared by the mother and her child begin during gestation when the mother is everything for the developing fetus, supplying warmth and sustenance, while her heartbeat provides a soothing constant rhythm. The physical connection between mother and fetus is provided by the placenta, an organ, built of cells from both the mother and fetus, which serves as a conduit for the exchange of nutrients, gasses, and wastes. Cells may migrate through the placenta between the mother and the fetus, taking up residence in many organs of the body including the lung, thyroid muscle, liver, heart, kidney and skin. These may have a broad range of impacts, from tissue repair and cancer prevention to sparking immune disorders. It is remarkable that it is so common for cells from one individual to integrate into the tissues of another distinct person. We are accustomed to thinking of ourselves as singular autonomous individuals, and these foreign cells seem to belie that notion, and suggest that most people carry remnants of other individuals. As remarkable as this may be, stunning results from a new study show that cells from other individuals are also found in the brain. In this study, male cells were found in the brains of women and had been living there, in some cases, for several decades. What impact they may have had is now only a guess, but this study revealed that these cells were less common in the brains of women who had Alzheimer’s disease, suggesting they may be related to the health of the brain. © 2012 Scientific American

Related chapters from BP7e: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 13: Memory, Learning, and Development; Chapter 8: Hormones and Sex
Link ID: 17579 - Posted: 12.05.2012

By Michelle Warwicker BBC Nature The youngest members of zebra finch broods "explore more" than older siblings in adult life, say scientists. Researchers investigated how the birds' behaviour was affected by the way their parents cared for them as hatchlings. The team studied broods where females lay and incubate a clutch of eggs over a period of days, resulting in a size hierarchy within the clutch. They found the youngest birds were more likely to explore their environment as adults in search of food. The study, published in Animal Behaviour, tested over 100 captive zebra finches' exploratory behaviour to see whether hatching order, and consequently parental investment, affected their behaviour in adulthood. Late hatched birds are smaller than their older siblings, and it is the larger hatchlings that "get the lion's share" when parents bring in food "because they can reach up higher and beg better," explained research team member Dr Ian Hartley from Lancaster University. Hatching eggs over a span of time, rather than all at once, is known as "hatching asynchrony" and occurs when eggs are incubated as soon as they are laid. For zebra finch, this means that birds born up to four days apart can share the same nest and must compete for food. BBC © 2012

Related chapters from BP7e: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 13: Memory, Learning, and Development; Chapter 11: Emotions, Aggression, and Stress
Link ID: 17563 - Posted: 12.03.2012

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