Chapter 7. Life-Span Development of the Brain and Behavior
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By Smitha Mundasad Health reporter, BBC News The risk of developing autism may be passed on through - and not just to - future generations, researchers say. The international study suggests older fathers are more likely to have grandchildren with autism than their younger counterparts. The mechanism is unclear but it is thought they may transmit "silent mutations" to their grandchildren. But experts have urged caution, stressing autism is the result of many different factors. The study, looking at almost 6,000 people with the condition, is published in the journal Jama Psychiatry. According to the National Autistic Society, more than one in every 100 people in the UK have the condition. Previous studies suggested older fathers may be at greater risk of having children with autism than younger dads. But the team of UK, Swedish and Australian researchers say this is one of the first pieces of evidence to show the risk can be passed on through - rather than just straight to - future generations. The "silent mutations" - changes in genetic material - are likely to have no obvious impact on older fathers' own children, but they may build up through subsequent generations, or interact with other genes and environmental factors, to increase the chance of their grandchildren developing the condition, the researchers say. BBC © 2013
by Peter Aldhous Women abused in childhood are more likely to have children with autism, a new epidemiological study suggests. The finding adds a disturbing new dimension to the heated debate over the condition's underlying causes. Andrea Roberts of the Harvard School of Public Health suspected that there might be a link between childhood abuse and having an autistic child: women abused early in life are more likely to smoke, suffer from gestational diabetes and have premature babies – all factors that may affect fetal brain development. To investigate, Roberts and her colleagues turned to the Nurses' Health Study II, which includes almost 55,000 women who had indicated if they had a child with autism spectrum disorder and also answered a questionnaire about their experience of abuse as a child. This allowed the researchers to develop a scale rating all the women for the intensity of abuse in their childhood. There was a clear link between the "dose" of abuse received and the risk of having an autistic child. "The associations get stronger as the level of abuse increases," Roberts says. After accounting for demographic factors such as age and socioeconomic status, the 2 per cent of women who reported the most serious childhood abuse – who were frequently hit and also sexually abused – were about 3.5 times as likely to have a child with autism as those who reported no abuse at all. "I think it's a really interesting, innovative and well-conducted study," says Hannah Gardener at the University of Miami in Florida. "There aren't a lot of risk factors with that magnitude." © Copyright Reed Business Information Ltd.
At 7 months of age, children who are later diagnosed with autism take a split second longer to shift their gaze during a task measuring eye movements and visual attention than do typically developing infants of the same age, according to researchers supported by the National Institutes of Health. The difference between the groups’ test results was 25 to 50 milliseconds on average, the researchers found, too brief to be detected in social interactions with an infant. However, they showed that this measurable delay could be accounted for by differences in the structure and organization of actively developing neurological circuits of a child’s brain. Image of brain structure known as the splenium of the corpus callosum When they were infants, children who were later diagnosed with autism took longer to shift their gaze during a measure of eye movements than did infants who were not diagnosed with autism. The researchers believe that brain circuits involved with a brain structure known as the splenium of the corpus callosum (shown in this scan) may account for the differences in gaze shifting between the two groups. Image courtesy of Jason Wolff, Ph.D., University of North Carolina at Chapel Hill. Efficiently shifting attention early in infancy is thought to be important for later social and cognitive development. Split-second delays, the researchers suggested, could be a precursor to such well known symptoms of autism as difficulty making eye contact or following a parent’s pointing finger, problems that generally emerge after a child turns 1. Typically, autism spectrum disorder (ASD) is not diagnosed until after 3 or 4 years of age. The study appears in the American Journal of Psychiatry.
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
A staggering 1 in 3 seniors dies with Alzheimer's disease or other types of dementia, says a new U.S. report that highlights the impact the mind-destroying disease is having on the rapidly aging population. Dying with Alzheimer's is not the same as dying from it. But even when dementia isn't the direct cause of death, it can be the final blow — speeding someone's decline by interfering with their care for heart disease, cancer or other serious illnesses. That's the assessment of the report released Tuesday by the Alzheimer's Association, which advocates for more research and support for families afflicted by it. "Exacerbated aging," is how Dr. Maria Carrillo, an association vice president, terms the Alzheimer's effect. "It changes any health care situation for a family." In fact, only 30 per cent of 70-year-olds who don't have Alzheimer's are expected to die before their 80th birthday. But if they do have dementia, 61 per cent are expected to die, the report found. Already, 5.2 million Americans have Alzheimer's or some other form of dementia. Those numbers will jump to 13.8 million by 2050, Tuesday's report predicts. That's slightly lower than some previous estimates. Count just the deaths directly attributed to dementia, and they're growing fast. Nearly 85,000 people died from Alzheimer's in 2011, the U.S. Centers for Disease Control and Prevention estimated in a separate report Tuesday. Those are people who had Alzheimer's listed as an underlying cause on a death certificate, perhaps because the dementia led to respiratory failure. Those numbers make Alzheimer's the sixth leading cause of death. © CBC 2013
Link ID: 17927 - Posted: 03.20.2013
By GINA KOLATA The Food and Drug Administration plans to loosen the rules for approving new treatments for Alzheimer’s disease. Drugs in clinical trial would qualify for approval if people at very early stages of the disease subtly improved their performance on memory or reasoning tests, even before they developed any obvious impairments. Companies would not have to show that the drugs improved daily, real-world functioning. For more than a decade, the only way to get Alzheimer’s drugs to market was with studies showing that they improved the ability of patients not only to think and remember, but also to function day to day at activities like feeding, dressing or bathing themselves. The proposal, published online Wednesday in The New England Journal of Medicine, could help millions of people at risk of developing the disease by speeding the development and approval of drugs that might slow or prevent it. The proposed policy could also be a boon for the pharmaceutical industry and researchers. They have often felt stymied by regulations that left them uncertain of how to get drugs tested and approved for marketing to people early in the course of Alzheimer’s, when the medications are most likely to be useful. Several studies are being planned for people at high risk of developing Alzheimer’s, and the proposed regulations should lead to even more clinical trials, said Dr. P. Murali Doraiswamy, an Alzheimer’s researcher and professor of psychiatry at Duke University School of Medicine. © 2013 The New York Times Company
Link ID: 17904 - Posted: 03.15.2013
By Jan Brogan Paula Driscoll had a hard time sitting still as a kid, doodled a lot, and often wrestled with the feeling that she should be accomplishing more. But she made it through high school and college and became an elementary school teacher. With three small children at home, she did not feel she had trouble managing her life. But when her youngest child went to school, she found herself with what felt like too much time on her hands. “I couldn’t get anything done,” she said. “I had one room I started to paint, another I was going to reorganize, and I could never complete a task. I couldn’t stay in the house. I went out on one errand after the next.” Driscoll was 45 when she was diagnosed with attention deficit hyperactivity disorder, or ADHD. ADHD, a neurobiological disorder that makes it difficult to focus and can also include hyperactivity and impulsivity, has historically been viewed as a childhood disease. Over the last couple decades, research has shown that many of those afflicted carry symptoms into adulthood. The latest study, led by a Boston Children’s Hospital researcher and published Monday in the journal Pediatrics, suggests that nearly 30 percent of those with childhood ADHD still have the condition as adults — often after discontinuing treatment. The researchers followed hundreds of children with ADHD into adulthood and reported that the majority had mental health problems such as alcohol or drug dependence, anxiety, depression, or a personality disorder. © 2012 NY Times Co.
British researchers have developed a test to detect Alzheimer's disease in its earliest stages. It works by looking for a combination of "markers" in the blood which are different in healthy people and those with the disease. Delegates at the Alzheimer's Research UK Conference heard that the University of Nottingham is now developing a quick and easy test to do in clinics. It could mean much earlier diagnosis and better treatments, they said. The test uses some proteins that have been strongly linked with Alzheimer's disease, such as amyloid and APOE. But through careful analysis of blood from people with the disease, as well as those with early-stage memory problems, the researchers detected some other markers that were suggestive of the disease. Most notably, some proteins related to inflammation seem to have been added to increase the power of the test. Prof Kevin Morgan from the University of Nottingham said they still had to validate the test and it could be a decade before it was used in patients. But he added that the combination of markers they had found was looking very promising. BBC © 2013
Link ID: 17889 - Posted: 03.11.2013
By GINA KOLATA The psychiatric illnesses seem very different — schizophrenia, bipolar disorder, autism, major depression and attention deficit hyperactivity disorder. Yet they share several genetic glitches that can nudge the brain along a path to mental illness, researchers report. Which disease, if any, develops is thought to depend on other genetic or environmental factors. Their study, published online Wednesday in the Lancet, was based on an examination of genetic data from more than 60,000 people worldwide. Its authors say it is the largest genetic study yet of psychiatric disorders. The findings strengthen an emerging view of mental illness that aims to make diagnoses based on the genetic aberrations underlying diseases instead of on the disease symptoms. Two of the aberrations discovered in the new study were in genes used in a major signaling system in the brain, giving clues to processes that might go awry and suggestions of how to treat the diseases. “What we identified here is probably just the tip of an iceberg,” said Dr. Jordan Smoller, lead author of the paper and a professor of psychiatry at Harvard Medical School and Massachusetts General Hospital. “As these studies grow we expect to find additional genes that might overlap.” The new study does not mean that the genetics of psychiatric disorders are simple. Researchers say there seem to be hundreds of genes involved and the gene variations discovered in the new study confer only a small risk of psychiatric disease. Steven McCarroll, director of genetics for the Stanley Center for Psychiatric Research at the Broad Institute of Harvard and M.I.T., said it was significant that the researchers had found common genetic factors that pointed to a specific signaling system. © 2013 The New York Times Company
Regina Nuzzo Despite having brains that are still largely under construction, babies born up to three months before full term can already distinguish between spoken syllables in much the same way that adults do, an imaging study has shown1. Full-term babies — those born after 37 weeks' gestation — display remarkable linguistic sophistication soon after they are born: they recognize their mother’s voice2, can tell apart two languages they’d heard before birth3 and remember short stories read to them while in the womb4. But exactly how these speech-processing abilities develop has been a point of contention. “The question is: what is innate, and what is due to learning immediately after birth?” asks neuroscientist Fabrice Wallois of the University of Picardy Jules Verne in Amiens, France. To answer that, Wallois and his team needed to peek at neural processes already taking place before birth. It is tough to study fetuses, however, so they turned to their same-age peers: babies born 2–3 months premature. At that point, neurons are still migrating to their final destinations; the first connections between upper brain areas are snapping into place; and links have just been forged between the inner ear and cortex. To test these neural pathways, the researchers played soft voices to premature babies while they were asleep in their incubators a few days after birth, then monitored their brain activity using a non-invasive optical imaging technique called functional near-infrared spectroscopy. They were looking for the tell-tale signals of surprise that brains display — for example, when they suddenly hear male and female voices intermingled after hearing a long run of simply female voices. © 2013 Nature Publishing Group
By Meghan Rosen Mouse brain cells scamper close to eternal life: They can actually outlive their bodies. Mouse neurons transplanted into rat brains lived as long as the rats did, surviving twice as long as the mouse’s average life span, researchers report online February 25 in the Proceedings of the National Academy of Sciences. The findings suggest that long lives might not mean deteriorating brains. “This could absolutely be true in other mammals — humans too,” says study author Lorenzo Magrassi, a neurosurgeon at the University of Pavia in Italy. The findings are “very promising,” says Carmela Abraham, a neuroscientist at Boston University. “The question is: Can neurons live longer if we prolong our life span?” Magrassi’s experiment, she says, suggests the answer is yes. One theory about aging, Magrassi says, is that every species has a genetically determined life span and that all the cells in the body wear out and die at roughly the same time. For the neurons his team studied, he says, “We have shown that this simple idea is certainly not true.” Magrassi’s team surgically transplanted neurons from embryonic mice with an average life span of 18 months into rats. To do so, the researchers slipped a glass microneedle through the abdomens of anesthetized pregnant mice. Then, using a dissecting microscope and a tool to illuminate the corn-kernel-sized mouse embryos, the researchers scraped out tiny bits of brain tissue and injected the neurons into fetal rat brains. After the rat pups were born, Magrassi and colleagues waited as long as three years, until the animals were near death, to euthanize the rats and dissect their brains. © Society for Science & the Public 2000 - 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
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.
Canadian researchers have found out how to restore normal vision to kittens with a lazy eye without using an eye patch. The cure was relatively simple — putting the kittens in complete darkness for 10 days. Once the kittens were returned to daylight, they regained normal vision in the lazy eye within a week, reported researchers at Dalhousie University in Halifax in the journal Current Biology this month. Lazy eye is a condition where the brain effectively turns off one eye. It affects about four per cent of the population in humans, and the most common treatment is fix the vision problem (for example, by using glasses) and then patch the good eye, forcing the person to use their bad eye. Kevin Duffy, a neuroscientist who co-authored the new study, told CBC's Quirks & Quarks that the condition is typically the result of a vision problem such as a cataract, a misalignment of the eyes, or poor focus in one eye, which then causes the brain to develop abnormally. "If the eye is providing abnormal vision, then the circuits that connect to that eye are going to develop abnormally," he said. The brain "becomes effectively disconnected." © CBC 2013
Stephen S. Hall Male sexual dysfunction is never pretty, even in nematodes. In normal roundworm courtship, a slender male will sidle up to a plump hermaphrodite, make contact, and then initiate a set of steps leading up to insemination: a sinuous backwards motion as he searches for the sexual cleft, a pause to probe, and finally the transfer of sperm. The whole business is usually over in a couple of minutes. “It's very slithery, and affectionate,” says Cornelia Bargmann, who has been observing the behaviour of this particular worm, Caenorhabditis elegans, for 25 years. Last October, scientists in Bargmann's laboratory at the Rockefeller University, New York, reported the discovery of a gene that seems to be crucial to successful mating. Disrupting the action of this gene causes male sexual confusion of almost epic pathos: nematodes with certain mutations poke tentatively at an inert hermaphrodite, making confused, fruitless curlicues around the potential mate. Occasionally the mutant male succeeds, but often he literally falls off the job and begins the search anew for a mate. Jennifer Garrison, a postdoc of Bargmann's who tracked the behaviour of these males, just shakes her head as she replays the scene on her computer screen. “Really sad,” she says. There are two punchlines to this story of thwarted invertebrate mating. One is the charming squeamishness with which Bargmann describes it, hesitating at words such as “vulva” and “spicule” and other anatomical gewgaws of roundworm reproduction. “As a well-brought-up Southern girl,” she says with a laugh, “it's still difficult to talk about this!” © 2013 Nature Publishing Group
By Erin Wayman BOSTON — “Birdbrain” may not be much of an insult: Humans and songbirds share genetic changes affecting parts of the brain related to singing and speaking, new research shows. The finding may help scientists better understand how human language evolved, as well as unravel the causes of speech impairments. Neurobiologist Erich Jarvis of Duke University Medical Center in Durham, N.C., and colleagues discovered roughly 80 genes that turn on and off in similar ways in the brains of humans and songbirds such as zebra finches and parakeets. This gene activity, which occurs in brain regions involved in the ability to imitate sounds and to speak and sing, is not present in birds that can’t learn songs or mimic sounds. Jarvis described the work February 15 at the annual meeting of the American Association for the Advancement of Science. Songbirds are good models for language because the birds are born not knowing the songs they will sing as adults. Like human infants learning a specific language, the birds have to observe and imitate others to pick up the tunes they croon. The ancestors of humans and songbirds split some 300 million years ago, suggesting the two groups independently acquired a similar capacity for song. With the new results and other recent research, Jarvis said, “I feel more comfortable that we can link structures in songbird brains to analogous structures in human brains due to convergent evolution.” © Society for Science & the Public 2000 - 2013
Changing the channel on what TV children watch could improve their behaviour, but watching too much regular programming may have harmful long-term consequences, new research suggests. In Monday's issue of the journal Pediatrics, researchers reported that preschoolers spent less time watching violent programming when they were randomly assigned to participate in a program that encouraged aggression-filled shows to be replaced with educational or empathy-building viewing compared with a control group. Muppets Bert, left, and Ernie, from the children's program Sesame Street, were created to teach preschoolers that people can be good friends with those who are very different from themselves, which builds empathy. "We demonstrated that an intervention to modify the viewing habits of preschool-aged children can significantly enhance their overall social and emotional competence and that low-income boys may derive the greatest benefit," Dr. Dimitri Christakis of Seattle Children's Research Institute and his co-authors concluded. "Although television is frequently implicated as a cause of many problems in children, our research indicates that it may also be part of the solution." There was no difference in total viewing time between the 820 families involved in the study. The educational or "prosocial" programs included Sesame Street, Dora the Explorer and Super Why. A second category of shows also promoted co-operative problem-solving and non-violent conflict resolution but inconsistently, such as on Mickey Mouse Clubhouse. © CBC 2013
Mo Costandi Prions are best known as the infectious agents that cause ‘mad cow’ disease and the human versions of it, such as variant Creutzfeldt–Jakob Disease. But the proteins also have at least one known useful function, in the cells that insulate nerves, and are suspected to have more. Now researchers have provided the first direct evidence that the proteins play an important role in neurons themselves. The team reports in the Journal of Neuroscience1 that prions are involved in developmental plasticity, the process by which the structure and function of neurons in the growing brain is shaped by experience. Prions come in two main forms: the normal version and the misfolded, infectious version. The normal version, known as cellular prion protein (or PrPC), is present in every cell of the body and helps to maintain the myelin sheath in the cells that protect the nerves2. But the molecule is abundant in neurons themselves, especially during development. Because it is tethered to the membrane, it is widely assumed to be involved in signalling between nerve cells, but little direct evidence has been found for this. Neurobiologist Enrico Cherubini of the International School for Advanced Studies in Trieste, Italy, and his colleagues therefore decided to look at the effects of electrical stimulation on slices of tissue from the hippocampus of healthy 3–7-day-old mice and of animals genetically engineered to lack the gene that encodes the prion protein. They used electrodes to stimulate individual cells at the same time as the networks of young neurons showed bursts of spontaneous electrical activity, or to simultaneously stimulate pairs of cells that are connected to each other. © 2013 Nature Publishing Group
by Gisela Telis A stint in the dark may be just what the doctor ordered—at least if you have "lazy eye." Researchers report that kittens with the disorder, a visual impairment medically known as amblyopia that leads to poor sight or blindness in one eye, can completely recover their vision by simply spending 10 days in total darkness. "It's a remarkable study, with real potential to change how we think about recovery from amblyopia," says neuroscientist Frank Sengpiel of Cardiff University in the United Kingdom who was not involved in the work. Amblyopia affects about 4% of the human population. It's thought to start with an imbalance in vision early in life: If one eye doesn't see as well as the other—because, for example, of a cataract or astigmatism—the brain reroutes most of the connections needed for visual processing to the "good" eye. Doctors often treat the condition by patching the good eye and forcing the brain to rely on the other eye, but the treatment risks damaging vision in the good eye, and if it doesn't succeed or occur early enough in a child's visual development, the vision loss in the impaired eye can be permanent. Earlier studies with cats, whose complex visual systems are good stand-ins for human vision, showed that neurons in the brain's visual centers shrink when the brain decides to disconnect from the bad eye, but that they grow again when the cats are placed in darkness. So neuroscientists Kevin Duffy and Donald Mitchell of Dalhousie University in Halifax, Canada, set out to test darkness itself as a treatment. © 2010 American Association for the Advancement of Science
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