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By JOHN NOBLE WILFORD Modern mothers love to debate how long to breast-feed, a topic that stirs both guilt and pride. Now — in a very preliminary finding — the Neanderthals are weighing in. By looking at barium levels in the fossilized molar of a Neanderthal child, researchers concluded that the child had been breast-fed exclusively for the first seven months, followed by seven months of mother’s milk supplemented by other food. Then the barium pattern in the tooth enamel “returned to baseline prenatal levels, indicating an abrupt cessation of breast-feeding at 1.2 years of age,” the scientists reported on Wednesday in the journal Nature. While that timetable conforms with the current recommendations of the American Academy of Pediatrics — which suggests that mothers exclusively breast-feed babies for six months and continue for 12 months if possible — it represents a much shorter span of breast-feeding than practiced by apes or a vast majority of modern humans. The average age of weaning in nonindustrial populations is about 2.5 years; in chimpanzees in the wild, it is about 5.3 years. Of course, living conditions were much different for our evolutionary cousins, the Neanderthals, extinct for the last 30,000 years. The findings, which drew strong skepticism from some scientists, were meant to highlight a method of linking barium levels in teeth to dietary changes. In the Nature report, researchers from the United States and Australia described tests among human infants and captive macaques showing that traces of the element barium in tooth enamel appeared to accurately reflect transitions from mother’s milk through weaning. The barium levels rose during breast-feeding and fell off sharply on weaning. © 2013 The New York Times Company

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: 18187 - Posted: 05.23.2013

By Scicurious Aging happens. As you get older, your body slows down, eventually your brain slows down, too. Some things go gradually, and some go suddenly. To many people, this might seem like a pretty random process. We used to think of aging this way, as just…well cells get old, which means we get old, too. DNA replication after a while starts making errors in repair, the errors build up, and on the whole body scale the whole thing just kind of goes downhill. It seems random. But in fact, it’s not. There are specific proteins which can help control this process. And one of these, NF-kB, in one particular brain region, may have a very important role indeed. NF-kB (which stands for nuclear factor kappa-light-chain-enhancer of activated B cells, which is why we use NF-kB) is a protein complex that has a lot of roles to play. It’s an important starting player in the immune system, where it helps to stimulate antibodies. It’s important in memory and stress responses. NF-kB is something called a transcription factor, which helps to control what DNA is transcribed to RNA, and therefore what proteins will eventually be produced. Transcription factors, as you can see, can have a very large number of functions. But in the hypothalamus, NF-kB may have the added function of helping to control aging. The hypothalamus is an area of many small nuclei (further sub areas of neurons) located at the base of the brain. It’s been coming more and more into vogue lately among neuroscientists. In the past, we were interested in the hypothalamus mostly for its role in controlling hormone release from the dangling pituitary gland before it, but now we are learning that the hypothalamus can play roles in fear, mood, food intake, reproduction, and now…aging. © 2013 Scientific American

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: 18152 - Posted: 05.14.2013

Chris Palmer NF-kB activation in neurons in the hypothalamus increases with age (left column), while the total number of neurons (middle column) and the total number of all cell types in the hypothalamus (right column) is maintained at a relatively steady rate across age groups. The area of the brain that controls growth, reproduction and metabolism also kick-starts ageing, according to a study published today in Nature1. The finding could lead to new treatments for age-related illnesses, helping people to live longer. Dongsheng Cai, a physiologist at Albert Einstein College of Medicine in New York, and his colleagues tracked the activity of NF-κB — a molecule that controls DNA transcription and is involved in inflammation and the body's response to stress — in the brains of mice. They found that the molecule becomes more active in the brain area called the hypothalamus as a mouse grows older. Further tests suggested that NF-κB activity helps to determine when mice display signs of ageing. Animals lived longer than normal when they were injected with a substance that inhibited the activity of NF-κB in immune cells called microglia in the hypothalamus. Mice that received a substance to stimulate the activity of NF-κB died earlier. “We have provided scientific evidence for the concept that systemic ageing is influenced by a particular tissue in the body,” says Cai. Health and well-being © 2013 Nature Publishing Group

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: 18108 - Posted: 05.02.2013

by Emily Underwood In the cartoon series named after them, Pinky and the Brain, two laboratory mice genetically enhanced to increase their intelligence plot to take over the world—and fail each time. Perhaps their creators hadn't tweaked the correct gene. Researchers have now found a genetic mutation that causes mammalian neural tissue to expand and fold. The discovery may help explain why humans evolved more elaborate brains than mice, and it could suggest ways to treat disorders such as autism and epilepsy that arise from abnormal neural development. In mice and humans alike, the cerebral cortex—the outermost layer of brain tissue associated with high-level functions such as memory and decision-making—starts out as a spherical sheet of tissue made up of only neural stem cells. As these stem cells divide, the cortex increases its surface area, expanding like an inflating balloon, says neuroscientist Victor Borrell of the Institute of Neurosciences of Alicante in Spain. Unlike the small, smooth mouse brain, however, the uppermost layers of tissue in the human brain cram millions of neurons into specialized folds and furrows responsible for complex tasks such as language and thought. Because the human cerebral cortex is generally considered "special," some scientists have hypothesized that the genes that govern its development of cortical folds and furrows are also unique to humans, Borrell says. In studies of neural development in mice, Stahl found that TRNP1 produces a protein that determines whether neural stem cells self-replicate, leading to a balloonlike expansion of cortical surface area, or whether they differentiate into a plethora of intermediate stem cell types and neurons, thickening the cortex and forming more complex brain structures. Based on that discovery, the team hypothesized that varying levels of the gene's expression in mice and humans might account for the varying levels of cortical thickness and different shapes between the two species. © 2010 American Association for the Advancement of Science

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: 18082 - Posted: 04.27.2013

By ABBY ELLIN Marvin Tolkin was 83 when he decided that the unexamined life wasn’t worth living. Until then, it had never occurred to him that there might be emotional “issues” he wanted to explore with a counselor. “I don’t think I ever needed therapy,” said Mr. Tolkin, a retired manufacturer of women’s undergarments who lives in Manhattan and Hewlett Harbor, N.Y. Though he wasn’t clinically depressed, Mr. Tolkin did suffer from migraines and “struggled through a lot of things in my life” — the demise of a long-term business partnership, the sudden death of his first wife 18 years ago. He worried about his children and grandchildren, and his relationship with his current wife, Carole. “When I hit my 80s I thought, ‘The hell with this.’ I don’t know how long I’m going to live, I want to make it easier,” said Mr. Tolkin, now 86. “Everybody needs help, and everybody makes mistakes. I needed to reach outside my own capabilities.” So Mr. Tolkin began seeing Dr. Robert C. Abrams, a professor of clinical psychiatry at Weill Cornell Medical College in Manhattan. They meet once a month for 45 minutes, exploring the problems that were weighing on Mr. Tolkin. “Dr. Abrams is giving me a perspective that I didn’t think about,” he said. “It’s been making the transition of living at this age in relation to my family very doable and very livable.” Mr. Tolkin is one of many seniors who are seeking psychological help late in life. Most never set foot near an analyst’s couch in their younger years. But now, as people are living longer, and the stigma of psychological counseling has diminished, they are recognizing that their golden years might be easier if they alleviate the problems they have been carrying around for decades. It also helps that Medicare pays for psychiatric assessments and therapy. Copyright 2013 The New York Times Company

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: 18061 - Posted: 04.23.2013

by Dennis Normile A human mother rocking a baby in her arms and a cat carrying her kitten by the scruff of its neck have the same physiological effect on both young animals and probably stem from the same maternal instinct to protect their young. That's the conclusion of a new study, which for the first time has compared the physiological impact of maternal carrying behaviors across species. The findings may lead to better parenting techniques for people and possibly to new ways to detect developmental disorders early in life. It's "really fascinating" work, says Oliver Bosch, a neurobiologist at the University of Regensburg in Germany, who was not involved in the research. "No one has looked at [this aspect] of maternal behavior in such detail." Japanese neuroscientist Kumi Kuroda began the study in her own home. She noticed that carrying her newborn baby boy while walking had a rapid calming effect on him. Back in her lab at the RIKEN Brain Science Institute, near Tokyo, she found that picking up mouse pups by the scruff of the neck makes them passive and easy to handle. Kuroda wondered if the same physiological processes were driving both behaviors. She and colleagues recorded pulse rates and observed the crying and squirming behavior of 12 infants, 1 to 6 months old, as each was left alone in a crib, held by its mother sitting in a chair, and carried as the mother walked around. In various durations and combinations of the three conditions, they found that the carried babies cried and squirmed the least and had the lowest pulse rates. Those left in the crib were the fussiest; holding the baby while sitting produced in-between results. What was particularly surprising, Kuroda says, was that when a mother started walking, the infant's pulse dropped, and the crying and squirming stopped within 2 to 3 seconds, not over several minutes. © 2010 American Association for the Advancement of Science.

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: 18048 - Posted: 04.20.2013

by Douglas Heaven A glimpse of consciousness emerging in the brains of babies has been recorded for the first time. Insights gleaned from the work may aid the monitoring of babies under anaesthesia, and give a better understanding of awareness in people in vegetative states – and possibly even in animals. The human brain develops dramatically in a baby's first year, transforming the baby from being unaware to being fully engaged with its surroundings. To capture this change, Sid Kouider at the Ecole Normale Supérieure in Paris, France, and colleagues used electroencephalography (EEG) to record electrical activity in the brains of 80 infants while they were briefly shown pictures of faces. In adults, awareness of a stimulus is known to be linked to a two-stage pattern of brain activity. Immediately after a visual stimulus is presented, areas of the visual cortex fire. About 300 milliseconds later other areas light up, including the prefrontal cortex, which deals with higher-level cognition. Conscious awareness kicks in only after the second stage of neural activity reaches a specific threshold. "It's an all-or-nothing response," says Kouider. Adults can verbally describe being aware of a stimulus, but a baby is a closed book. "We have learned a lot about consciousness in people who can talk about it, but very little in those who cannot," says Tristan Bekinschtein at the University of Cambridge, who was not involved in the work. © Copyright Reed Business Information Ltd.

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: 18047 - Posted: 04.20.2013

by Elizabeth Norton A loving gaze helps firm up the bond between parent and child, building social skills that last a lifetime. But what happens when mom is blind? A new study shows that the children of sightless mothers develop healthy communication skills and can even outstrip the children of parents with normal vision. Eye contact is one of the most important aspects of communication, according to Atsushi Senju, a developmental cognitive neuroscientist at Birkbeck, University of London. Autistic people don't naturally make eye contact, however, and they can become anxious when urged to do so. Children for whom face-to-face contact is drastically reduced—babies severely neglected in orphanages or children who are born blind—are more likely to have traits of autism, such as the inability to form attachments, hyperactivity, and cognitive impairment. To determine whether eye contact is essential for developing normal communication skills, Senju and colleagues chose a less extreme example: babies whose primary caregivers (their mothers) were blind. These children had other forms of loving interaction, such as touching and talking. But the mothers were unable to follow the babies' gaze or teach the babies to follow theirs, which normally helps children learn the importance of the eyes in communication. Apparently, the children don't need the help. Senju and colleagues studied five babies born to blind mothers, checking the children's proficiency at 6 to 10 months, 12 to 15 months, and 24 to 47 months on several measures of age-appropriate communications skills. At the first two visits, babies watched videos in which a woman shifted her gaze or moved different parts of her face while corresponding changes in the baby's face were recorded. Babies also followed the gaze of a woman sitting at a table and looking at various objects. © 2010 American Association for the Advancement of Science

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: 18023 - Posted: 04.11.2013

By DOUGLAS QUENQUA The French geneticist Jérôme Lejeune discovered more than 50 years ago that Down syndrome is caused by the presence of an extra copy of chromosome 21. But to this day it has remained a mystery why that results in impaired physical and cognitive development. Now researchers at the Sanford-Burnham Medical Research Institute think they have found a clue. The scientists, who were investigating Alzheimer’s disease, found that mice that lacked a protein known as SNX27 had many of the same learning and memory defects as mice with Down syndrome. Looking at the brains of people with the syndrome, the researchers discovered that they, too, lacked SNX27. While chromosome 21 is not directly involved in SNX27 production, it does encode a regulator — miR-155 — that inhibits production. According to the study, published in the journal Nature Medicine, levels of miR-155 in the brains of people with Down syndrome correlate almost exactly with the decrease in SNX27. “In the brain, SNX27 keeps certain receptors on the cell surface — receptors that are necessary for neurons to fire properly,” said the study’s senior author, Huaxi Xu, in a statement released by the institute. “So in Down syndrome, we believe lack of SNX27 is at least partly to blame for developmental and cognitive defects.” To test their findings, Dr. Xu’s team introduced more SNX27 to mice with Down syndrome. As they expected, the mice showed immediate improvements in cognitive function and behavior. Now the researchers are investigating molecules that might increase production of SNX27 in the human brain. © 2013 The New York Times Company

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: 18002 - Posted: 04.09.2013

by Dennis Normile Puberty has always been a time of stress and emotional turmoil for adolescents and for their parents. And scientists have long recognized that kids who start puberty ahead of their peers are particularly likely to have trouble getting along with other children and with adults. New research suggests that those difficulties can be traced back to even earlier ages, indicating that early puberty may not be the root cause. Australian researchers drew on data for 3491 children, roughly half boys and half girls, who were recruited at ages 4 or 5 and then followed until they reached ages 10 or 11. Every 2 years, a researcher visited each subject's home, evaluated the child, and interviewed the primary caregiver, which in most cases was a parent, who later completed and returned a questionnaire about their child's behavior. The primary caregiver was also asked to judge the child's pubertal status, based on indicators for an early phase of puberty such as breast growth in girls, adult-type body odor, and body hair; and growth spurts, deepening voices in boys, and menstruation in girls for a later stage. Girls typically enter puberty at age 10 or 11 and boys at 11 or 12. The researchers found that 16% of the girls and 6% of the boys in the study had entered puberty early, at age 8 or 9. Previously, researchers thought that any negative effects of early puberty showed up only after puberty's onset. But by tracking a cohort of children from age 4 to 5 to age 10 to 11, they found that problems thought restricted to postpuberty children actually appeared well before puberty. Retrospectively, they were able to show that children who later had early onset puberty had difficulty playing with other children and participating in normal school activities, even when they were 4 or 5 years old. Boys, though not girls, in this group had also showed behavior problems, such as being overactive, losing their tempers, and preferring to play alone from a young age. © 2010 American Association for the Advancement of Science.

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: 17987 - Posted: 04.03.2013

A lack of a protein in Down's syndrome brains could be the cause of learning and memory problems, says a US study. Writing in Nature Medicine, Californian researchers found that the extra copy of chromosome 21 in people with the condition triggered the protein loss. Their study found restoring the protein in Down's syndrome mice improved cognitive function and behaviour. The Down's Syndrome Association said the study was interesting but the causes of Down's were very complex. Prof Huaxi Xu, senior author of the study from the Sanford-Burnham Medical Research Institute, said that in experiments on mice they discovered that the SNX27 protein was important for brain function and memory formation. Mice with less SNX27 had fewer active glutamate receptors and therefore had impaired learning and memory. The SNX27-deficient mice shared some characteristics with Down's syndrome, so the researchers looked at human brains with the condition. This confirmed their findings in the lab - that people with Down's syndrome also have significantly lower levels of SNX27. BBC © 2013

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: 17945 - Posted: 03.25.2013

By Bruce Bower Malnutrition in the first year life, even when followed by a good diet and restored physical health, predisposes people to a troubled personality at age 40, new research suggests. The study of 77 formerly malnourished people represents the first evidence linking malnutrition shortly after birth to adult personality traits. The traits in some cases may foretell psychiatric problems, says a team led by psychiatrist Janina Galler of Harvard Medical School in Boston and psychologist Paul Costa of Duke University Medical Center in Durham. Compared with peers who were well-fed throughout their lives, formerly malnourished men and women reported markedly more anxiety, vulnerability to stress, hostility, mistrust of others, anger and depression, Galler’s team reports March 12 in the Journal of Child Psychology and Psychiatry. Survivors of early malnutrition also cited relatively little intellectual curiosity, social warmth, cooperativeness and willingness to try new experiences and to work hard at achieving goals. Previous studies of people exposed prenatally to famine have reported increased rates of certain personality disorders and schizophrenia. Another investigation found that malnutrition at age 3 predisposed youngsters on the Indian Ocean island of Mauritius to delinquent and aggressive behavior at ages 8, 11 and 17. As is true in the new study, distrust of others, anxiety and depression often accompany high levels of anger, says psychologist Adrian Raine of the University of Pennsylvania in Philadelphia, who directed the Mauritius research. “Poor nutrition early in life seems to predispose individuals to a suspicious personality, which may then fuel a hostile attitude toward others,” Raine proposes. © Society for Science & the Public 2000 - 2013

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: 17930 - Posted: 03.23.2013

By Janet Raloff Hospitals rush newborns into a neonatal intensive care unit when those babies are struggling to survive. Although NICUs offer tender and vigilant care, many of the devices they rely on can expose their tiny patients to a relatively large dose of a hormone-mimicking pollutant, bisphenol A. Newborns in intensive care excrete BPA, on average, at levels of around 17.8 micrograms per liter — well above the 0.45 µg/l typical of healthy infants, researchers report in the March Pediatrics. One of the most reliable indicators of BPA exposure was the level of care that a baby received, reflected by the number of devices used to deliver that care, notes nurse and exposure-science researcher Susan Duty of Simmons College in Boston. Breathing tubes, intravenous drug delivery lines and enclosed incubators are plastic, and several types of plastic can contain BPA. Although researchers have not figured out what doses of BPA cause toxicity in people, several studies have linked elevated prenatal exposures to later behavioral problems (SN Online: 7/16/12) and moodiness (SN: 11/7/09, p. 12) in young children. Animal studies have also linked BPA exposure during development to feminization in males and risks of later hypertension and diabetes. Duty’s team studied 55 infants, each of whom spent at least three days in a NICU in the Boston area, and most of whom had been born prematurely or were for other reasons very small. The researchers measured BPA in the breast milk and formula that these tiny babies consumed. Both nutritional sources had small, comparable amounts of BPA. © Society for Science & the Public 2000 - 2013

Related chapters from BP7e: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 13: Memory, Learning, and Development; Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Link ID: 17835 - Posted: 02.23.2013

Sandrine Ceurstemont, editor, New Scientist TV It's the sequel to fertilisation: the brains of unborn babies have now been imaged in action, showing how connections form. This fMRI movie, produced by Moriah Thomason from Wayne State University in Detroit, Michigan, shows a fly-through of several fetuses in their third trimester. By comparing the scans at slightly different stages of development, Thomason was able to pinpoint when different parts of the brain wire up. "The connection strength increases with fetal age," writes Thomason. By identifying how brain connectivity normally develops, the scans could help diagnose and treat conditions like schizophrenia and autism before birth. For more on this research, read our full-length news story, "First snaps made of fetal brains wiring themselves up". © Copyright Reed Business Information Ltd.

Related chapters from BP7e: Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 2: Cells and Structures: The Anatomy of the Nervous System; Chapter 13: Memory, Learning, and Development
Link ID: 17834 - Posted: 02.23.2013

By Emily Chung, CBC News Among musicians who learned to play an instrument before the age of seven, earlier training was linked to more connections in the area of the brain that co-ordinates both hands.Among musicians who learned to play an instrument before the age of seven, earlier training was linked to more connections in the area of the brain that co-ordinates both hands. (Jorge Silva/Reuters) Starting piano or violin lessons before the age of seven appears to cause permanent changes to the brain that are linked to better motor skills. Those changes in brain development don't occur in people who learn to play an instrument when they are older, a new study has found. "What we think is that it doesn't mean you can't be an amazing musician if you start later — just that if you start earlier it may give you some of these specific abilities that are helpful," said Virginia Penhune, a Concordia University psychologist who co-authored the research with two of her doctoral students and McGill University neuropsychologist Robert Zatorre. The Montreal researchers gave a test of motor skills to and scanned the brains of 36 musicians who were either enrolled in a university music program or performed professionally, and who had an average of 16 years experience playing musical instruments. Half of them began their musical training between age three and seven, while the other half started between the ages of eight and 18, but both groups had a comparable level of experience. The study also tested 17 non-musicians. © CBC 2013

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 13: Memory, Learning, and Development
Link ID: 17804 - Posted: 02.14.2013

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