Teens can be so messed up because their brains are getting restructured.
Philadelphia, March 28, 2008 – Many parents are convinced that the brains of their teenage offspring are different than those of children and adults. New data confirms that this is the case. An article by Jay N. Giedd, MD, of the National Institute of Mental Health (NIMH), published in the April 2008 issue of the Journal of Adolescent Health describes how brain changes in the adolescent brain impact cognition, emotion and behavior.
Dr. Giedd reviews the results from the NIMH Longitudinal Brain Imaging Project. This study and others indicate that gray matter increases in volume until approximately the early teens and then decreases until old age. Pinning down these differences in a rigorous way had been elusive until MRI was developed, offering the capacity to provide extremely accurate quantifications of brain anatomy and physiology without the use of ionizing radiation.
Our brains go through big changes during adolescence. The brain gets a lot of executive function enhancements.
The NIMH Longitudinal Brain Imaging Project began in 1989. Participants visit the NIMH at approximately two-year intervals for brain imaging, neuropsychological and behavioral assessment and collection of DNA. As of September 2007, approximately 5000 scans from 2000 subjects have been acquired. Of these, 387 subjects, aged 3 to 27 years, have remained free of any psychopathology and serve as the models for typical brain development.
Three themes have emerged from this and other studies in this new era of adolescent neuroscience. The first is functional and structural increases in connectivity and integrative processing as distributed brain modules become more and more integrated. Using a literary metaphor, maturation would not be the addition of new letters but rather of combining earlier formed letters into words, and then words into sentences and then sentences into paragraphs.
The second is a general pattern of childhood peaks of gray matter (frontal lobe, parietal lobe, temporal lobe and occipital lobe) followed by adolescent declines. As parts of the brain are overdeveloped and then discarded, the structure of the brain becomes more refined.
The third theme is a changing balance between limbic/subcortical and frontal lobe functions that extends well into young adulthood as different cognitive and emotional systems mature at different rates. The cognitive and behavioral changes taking place during adolescence may be understood from the perspective of increased “executive” functioning, a term encompassing a broad array of abilities, including attention, response inhibition, regulation of emotion, organization and long-range planning.
What would be helpful: ways to identify when a kid's brain development has entered a stage which makes them more dangerous to self or other due. Detect a deficiency of functions that make them better able to understand themselves and others and more able to restraint their actions.
I can imagine some day drivers license requirements will include brain scans to show that one is not obviously prone to rash and dangerous actions. Also, I can imagine the development of drugs that will speed a teenager more quickly through stages since moms would just as soon have kids with more mature personalities once the kids hit adolescence.
The omega 3 fatty acid is suspected of boosting infant brain development.
Quebec City, April 9, 2008—A study supervised by Université Laval researchers Gina Muckle and Éric Dewailly reveals that omega-3 intake during the last months of pregnancy boosts an infant’s sensory, cognitive, and motor development. The details of this finding are published in a recent edition of the Journal of Pediatrics.
To come to this conclusion, researchers first measured docosahexaenoic acid (DHA) concentration—a type of omega-3 fatty acid involved in the development of neurons and retinas—in the umbilical cord blood of 109 infants. “DHA concentration in the umbilical cord is a good indicator of intra-uterine exposure to omega-3s during the last trimester of pregnancy, a crucial period for the development of retinal photoreceptors and neurons,” explains Dr. Dewailly.
Tests conducted on these infants at 6 and 11 months revealed that their visual acuity as well as their cognitive and motor development were closely linked to DHA concentration in the umbilical cord blood at the time of their birth. However, there was very little relation between test results and DHA concentration in a mother’s milk among infants who were breast-fed. “These results highlight the crucial importance of prenatal exposure to omega-3s in a child’s development,” points out Dr. Muckle.
This is not the first study to make that claim. But a lot of factors influence intellectual development including genetics. It is hard to prove the influence of this one factor. Still, given DHA's role in nerve cell membranes this claim seems highly plausible.
These results deal with averages of course. But personality types identifiable in preschool children have lasting effects.
Participants consisted of 230 children who were studied every year from their first or second year in preschool until age 12. After age 12, the sample was reassessed twice, at ages 17 and 23. Researchers led by Jaap Denissen of Humboldt-University Berlin assessed degrees of shyness and aggressiveness through parental scales and teacher reports.
Denissen tested the hypotheses on the predictive validity of three major preschool personality types. Resilient personality is characterized by above average emotional stability, IQ, and academic achievement. Overcontrol is characterized by low scores on extraversion, emotional stability, and self-esteem. Undercontrol is characterized by low scores on emotional stability and agreeableness and high scores on aggressive behavior.
The 19-year longitudinal study illustrated that childhood personality types were meaningfully associated with the timing of the transitions. Resilient males were found to leave their parents’ house approximately one year earlier than overcontrolled or undercontrolled children. Overcontrolled boys took more than a year longer than others in finding a romantic partner. Resilient boys and girls were faster in getting a part-time job than their overcontrolled and undercontrolled peers.
Okay, when offspring genetic engineering becomes possible will prospective parents opt to give their kids genetic variations that make them resilient personalities or maybe undercontrolled or overcontrolled? I'm expecting parents to boost the IQ of their kids. But will they go too far in giving the kids extraversion or perhaps make them too emotionally controlled?
Some kids have genes that make them better able to handle abuse with fewer long term repercussions.
Some forms of a gene that controls the body's response to stress hormones appear to protect adults who were abused in childhood from depression, psychiatrists have found.
People who had been abused as children and who carried the most protective forms of the gene, called corticotropin-releasing hormone receptor one (CRHR1), had markedly lower measures of depression, compared with people with less protective forms, the researchers found in a recent study.
The findings could guide doctors in finding new ways to treat depression in people who were abused as children, says senior author Kerry Ressler, MD, PhD, assistant professor of psychiatry and behavioral sciences at Emory University School of Medicine.
This is not the first report of genetic variations of brain genes that affect how well developing children handle abuse and adversity. Previous research found that children who carry the low MAOA activity allele (MAOA-L) and who are abused demonstrate more aggressive and violent behavior as adults.
Some kids have genes that let them shrug off all sorts of abuse and basically keep trucking. Other kids aren't so lucky. Those latter kids become problems for the rest of us too. Violence prone adults pose a danger to whoever they come into contact with.
Early identification of kids with genetic vulnerabilities might some day get used to guide more aggressive state intervention into bad families. You can imagine social workers arguing to take a kid out of an abusive home more quickly if the has genes that make him or her vulnerable to permanent and problematic behavioral and personality alterations.
Once offspring genetic engineering becomes possible we can't assume parents should avoid giving offspring these genetic variations that make kids more vulnerable to abuse. There might be benefits to these alleles in more benign environments. Though I see a more compelling argument for discouraging the passing along of these alleles if either prospective parent has a genetic profile and brain scans that suggests he or she is likely to abuse kids.
A team of scientists at the University of Melbourne in Australia watched some 11 to 14 year old early adolescent children discuss points of disagreement with their parents and measured their reactions. Then the scientists measured the size of brain areas in each of the children. Well, the children more prone to tantrums and sulking had different sizes of various brain areas as compared to the more agreeable children. Is anyone surprised by this result?
Next the team scanned the children’s brains, focusing on three regions: the amygdala, which triggers impulsive reactions to emotional situations, and the anterior cingulate cortex (ACC) and orbitofrontal cortex (OFC) – pre-frontal parts of the brain involved in more thoughtful and reflective responses.
Children of both sexes who behaved more aggressively during the problem-solving tasks had bigger amygdalas, while boys who had smaller ACCs on the left side of the brain, compared with the right, stayed aggressive for longer. Also, boys with smaller OFCs on the left side were more likely to respond to a parent’s sulky behaviour with a sulk of their own.
Picture our genetically engineered future. I expect many prospective parents to opt to give their offspring genetic variations that will make their brains develop bigger anterior cingulate cortex (ACC) and orbitofrontal cortex (OFC) brain regions and to develop those regions sooner during adolescence. Just genetically engineer surliness and brattiness right out of kids. Why not?
From the abstract of the PNAS paper:
In a sample of 137 early adolescents, we investigated the relationship between aspects of the adolescents' brain structure and their affective behavior as assessed during observation of parent–child interactions. We found a significant positive association between volume of the amygdala and the duration of adolescent aggressive behavior during these interactions. We also found male-specific associations between the volume of prefrontal structures and affective behavior, with decreased leftward anterior paralimbic cortex volume asymmetry associated with increased duration of aggressive behavior, and decreased leftward orbitofrontal cortex volume asymmetry associated with increased reciprocity of dysphoric behavior. These findings suggest that adolescent brain structure is associated with affective behavior and its regulation in the context of family interactions, and that there may be gender differences in the neural mechanisms underlying affective and behavioral regulation during early adolescence. Particularly as adolescence marks a period of rapid brain maturation, our findings have implications for mental health outcomes that may be revealed later along the developmental trajectory.
For most kids the bratty punk surly rude inconsiderate phase won't last. But the behavior of some adults suggests that not all escape from this phase. These who get stuck in adolescence probably need brain gene therapy to push their brains along a sorely needed development path.
Team leader Nicholas Allen, a clinical psychologist with the University of Melbourne and the Orygen Research Centre, said: "The good news is that to a certain extent it's a phase. Parents do find it helpful to understand that some of the inexplicable behaviours teenagers come up with is part of a brain developmental phase."
Professor Allen said that the research also cast light on why teenagers who one day approached tasks with a maturity beyond their years could act with immaturity the next. “Your 6ft 2 son can manage some very complicated work yet still do these dumb things. ‘What were you thinking?’ has been asked by every parent of teenagers,” he said.
Also see my previous post Adolescence Is Tough On The Brain.
Lead toxicity to the brain appears to kick in at pretty low blood levels of lead.
Even very small amounts of lead in children's blood -- amounts well below the current federal standard -- are associated with reduced IQ scores, finds a new six-year Cornell study.
The study examined the effect of lead exposure on cognitive function in children whose blood-lead levels (BLLs) were below the Centers for Disease Control and Prevention (CDC) standard of 10 micrograms per deciliter (mcg/dl) -- about 100 parts per billion. The researchers compared children whose BLLs were between 0 and 5 mcg/dl with children in the 5-10 mcg/dl range.
"Even after taking into consideration family and environmental factors known to affect a child's cognitive performance, blood lead played a significant role in predicting nonverbal IQ scores," says Richard Canfield, a senior researcher in Cornell's Division of Nutritional Sciences and senior author of the study in the journal Environmental Health Perspectives. "We found that the average IQ scores of children with BLLs of only 5 to 10 mcg/dl were about 5 points lower than the IQ scores of children with BLLs less than 5 mcg/dl. This indicates an adverse effect on children who have a BLL substantially below the CDC standard, suggesting the need for more stringent regulations," he said.
Vitamin C (ascorbic acid) and B1 (thiamine) enhance lead excretion. Screening of children in high risk neighborhoods might identify neighborhoods where children should take a multivitamin that will raise their IQs by reducing lead toxicity. A 5 point IQ jump would pay back the cost of the screening and vitamins many times over.
Kids with attention deficit develop in some areas their brains 3 years later than non-ADHD kids.
In youth with attention deficit hyperactivity disorder (ADHD), the brain matures in a normal pattern but is delayed three years in some regions, on average, compared to youth without the disorder, an imaging study by researchers at the National Institutes of Health’s (NIH) National Institute of Mental Health (NIMH) has revealed. The delay in ADHD was most prominent in regions at the front of the brain’s outer mantle (cortex), important for the ability to control thinking, attention and planning. Otherwise, both groups showed a similar back-to-front wave of brain maturation with different areas peaking in thickness at different times (see movie below).
“Finding a normal pattern of cortex maturation, albeit delayed, in children with ADHD should be reassuring to families and could help to explain why many youth eventually seem to grow out of the disorder,” explained Philip Shaw, M.D., NIMH Child Psychiatry Branch, who led research team.
So then maybe all those ADHD boys shouldn't be on Ritalin. Maybe we should let restless boys be restless and not expect them to act like calm girls.
Do ADHD kids who took Ritalin for years demonstrate higher or lower cognitive performance as adults than ADHD kids who do not take Ritalin?
Also, while I'm asking: Do the brains of ADHD kids develop more slowly because of genes, nutrition, or some other reason? I'm guessing it is at least partly genetic.
Children whose mothers have lower waist-hip ratio (WHR) are smarter.
Upper-body fat has negative effects and lower-body fat has positive effects on the supply of long-chain polyunsaturated fatty acids that are essential for neurodevelopment. Thus, waist-hip ratio (WHR), a useful proxy for the ratio of upper-body fat to lower-body fat, should predict cognitive ability in women and their offspring. Moreover, because teenage mothers and their children compete for these resources, their cognitive development should be compromised, but less so for mothers with lower WHRs. These predictions are supported by data from the Third National Health and Nutrition Examination Survey. Controlling for other correlates of cognitive ability, women with lower WHRs and their children have significantly higher cognitive test scores, and teenage mothers with lower WHRs and their children are protected from cognitive decrements associated with teen births. These findings support the idea that WHR reflects the availability of neurodevelopmental resources and thus offer a new explanation for men's preference for low WHR.
They suspect the omega-3 fatty acids in particular as beneficial. So women should eat salmon while pregnant and while nursing.
The answer could be encountered in omega-3 fatty acids, stored in the hips and thighs and which make a large percentage of the human brain. This type of fatty acids is stored by the female body below the waist with the installation of the puberty.
The male obsession with curviness shows how responsible we are to want smarter kids.
"Men respond because it's reproductively important," Lassek says.
This is not the only evolutionary reason why men prefer curvier women. Women With Hourglass Bodies Have More Reproductive Hormones.
What I wonder: Does the draining of omega 3 fatty acids from a woman in the last trimester of pregnancy contribute to post-partum depression? Check out some of the evidence on omega 3 fatty acids and depression here and here and here.
Also see my post Higher Fish Diet Seems To Make Babies Smarter.
Update: In fact, Joseph R. Hibbeln of the National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, has found evidence that postpartum depression is more common among women with lower omega 3 fatty acids (PDF format).
Higher fish consumption looks highly beneficial as protection against postpartum depression.
The new study is an analysis of 11,721 British women. Researchers found that the more omega-3 fatty acids a woman consumed in seafood during the third trimester, the less likely she was to show signs of major depression at that time and for up to eight months after the birth.
In fact, the rate of depression in the women with the highest intakes was only about half that of women with the lowest intakes, says senior author and psychiatrist Dr. Joseph R. Hibbeln.
Omega 3 fatty acids is one of the two nutrients most people should try to get more of. Vitamin D is the other one. go for salmon and sardines to get more omega 3 fatty acids. It'll even reduce the chances you'll commit a crime.
Here is news some new moms can use. Whether breast feeding will boost offspring IQ comes down to which genetic variations the babies carry.
DURHAM, N.C. – The known association between breast feeding and slightly higher IQ in children has been shown to relate to a particular gene in the babies, according to a report this week in the Proceedings of the National Academy of Sciences.
In two studies of breast-fed infants involving more than 3,000 children in Britain and New Zealand, breastfeeding was found to raise intelligence an average of nearly 7 IQ points if the children had a particular version of a gene called FADS2.
The distribution of FADS2 genetic variants probably varies around the world. Anyone know of a source of data for FADS2 genetic variant distributions in human races and local ethnic groups? That information would probably indicate whether results would hold up in all human populations.
"There has been some criticism of earlier studies about breastfeeding and IQ that they didn't control for socioeconomic status, or the mother's IQ or other factors, but our findings take an end-run around those arguments by showing the physiological mechanism that accounts for the difference," said Terrie Moffitt, a professor of psychological and brain sciences in Duke University's Institute for Genome Sciences and Policy.
Moffitt, who performed the research with her husband and co-author Avshalom Caspi at King's College in London, found that the baby's intellectual development is influenced by both genes and environment or, more specifically, by the interaction of its genes with its environment.
"The argument about intelligence has been about nature versus nurture for at least a century," Moffitt said. "We're finding that nature and nurture work together."
These results suggest that most women should breast feed. Only 10% of the women in the study groups had babies with genetic profiles which prevented a benefit from breast feeding.
Ninety percent of the children in the two study groups had at least one copy of the "C" version of FADS2, which yielded higher IQ if they were breast-fed. The other 10 percent, with only the "G" versions of the gene, showed no IQ advantage or disadvantage from breastfeeding.
A cheap test for FADS2 variants could help millions of women weigh the costs and benefits of breast feeding. Find out from a genetic test whether newly born junior will turn out smarter if you structure your life so that breast feeding is practical.
The benefit of the "C" version of FADS2 might come from its ability to convert other fatty acids to DHA.
The gene was singled out for the researchers' attention because it produces an enzyme that helps convert dietary fatty acids into the polyunsaturated fatty acids DHA (docosahexaenoic acid) and AA (arachidonic acid) that have been shown to accumulate in the human brain during the first months after birth.
A baby formula high in DHA might deliver the same benefit as breast feeding and deliver that benefit regardless of genetic variations carried by a baby. Mom eating salmon every day and then breast feeding might similarly deliver that benefit regardless of genetic variation.
A 7 point IQ boost is a really big deal. A country that boosted its average IQ by 7 points would experience a huge boost in economic growth and a rise in per capita GDP as the smarter kids made their way into the labor market.
Special videos not magic mental development tool for babies.
The Seattle team surveyed more than 1,000 families in February 2006 and found that infants between 8 and 16 months who regularly watched Baby Einstein and Brainy Baby videos knew substantially fewer words -- six to eight out of 90 -- than infants who did not watch them, according to parental reports. The deficit, which increased with each hour of video viewing, was not seen among babies who watched other programming, such as "Sesame Street" or "SpongeBob SquarePants" or adult shows such as "Oprah."
The study, published in the Journal of Pediatrics, is the first to examine the impact of videos that have been heavily promoted as educational, according to lead author Frederick J. Zimmerman, a University of Washington associate professor of public health and pediatrics. Zimmerman called the negative effect "large and significant" but said the study stopped short of establishing a causal connection.
I would expect babies to learn more from interacting with humans since interactions provide feedbacks on what they do.
What is striking to me about a story like this one is the lengths that some people will go to try to boost the mental development of little Johnnie and Jill. Imagine what parents will do once real mental boosting biotechnologies become available. A drug that boosts IQ by 10 points if taken for several years during childhood would be a big seller. But at least in some of the Western industrialized countries getting such drugs approved will be very difficult. The problem of how to prove safety is enormous. This leads me to expect bigger IQ boosts will happen in less developed countries which lack big drug regulatory agencies.
Much bigger IQ boosts will become available via genetic tinkering at the time of conception. The use of multiple embryos with pre-implantation genetic diagnosis (aka PIGD or PGD) to choose the potentially smartest embryo will a face fewer regulatory obstacles than the use of gene therapy to modify embryo genes. But the latter will offer far greater potential for intellectual boosting once scientists identify all the genetic variations that influence intelligence and once embryo genetic engineering techniques become fairly mature and safe.
More fish for developing fetuses?
Washington, D.C. ---- Today a Maternal Nutrition Group comprised of top professors of obstetrics and doctors of nutrition from across the country, in partnership with the National Healthy Mothers, Healthy Babies Coalition (HMHB), unveiled recommendations for seafood consumption during pregnancy. The recommendations come at a time when the debate about mercury in fish and an FDA/EPA advisory have created confusion for pregnant women, causing a reduction in their fish consumption. This leads to inadequate intake of omega-3 fatty acids resulting in risks to their health and the health of their children. This inadequate intake of fish is confirmed by data from the National Health and Nutrition Examination Survey (NHANES), which shows that 90 percent of women are consuming less than the FDA-recommended amount of fish.
The Group recommended that women who want to become pregnant, are pregnant or are breastfeeding should eat a minimum of 12 ounces per week of fish like salmon, tuna, sardines and mackerel, and can do so safely. The Group found that eating fish is the optimal way to gain the benefits of long-chain omega-3 fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Seafood is the richest dietary source of DHA and EPA in Americans’ diets. The Group also recognized that selenium, an essential mineral found in certain ocean fish, accumulates and appears to protect against the toxicity from trace amounts of mercury.
This advice is controversial and disputed by some. Also see here. Currently the US Food and Drug Administration recommends a maximum of 12 ounces of low mercury fish for pregnant women. But given the enormous range of mercury concentrations found in different fish species I think their advice should have been more nuanced. What is the justification for restricting salmon consumption to 12 ounces per week for example? Salmon is one of the richest omega 3 sources (and yours truly eats it 5 times a week on average) and salmon has very little mercury in it.
Omega 3 fatty acids are likely to boost baby intelligence, reduce the incidence of auto-immune diseases, delay Alzheimer's disease, reduce risk of macular degeneration, and reduce all-cause mortality. Omega 3s also appear to reduce depression and increase brain grey matter. Also, in practice the omega 3 fatty acids in fish seem to benefit babies more than the mercury might hurt them. My take: Omega 3 fatty acids deliver so many health benefits and fish sources are in such limited supply that we need seed companies to genetically engineer into grains the enzymes for making omega 3 fatty acids. Or how about transgenic pigs that make omega 3 fatty acids?
Two brain control networks found in adults exist as a single merged control network in children.
Two recently discovered control networks that govern voluntary brain activity in adults start life as a single network in children, report neuroscientists at Washington University School of Medicine in St. Louis.
Researchers previously showed the networks supervise most goal-oriented brain activity, enlisting the specialized talents of multiple brain regions for goal-oriented tasks as diverse as reading a word, listening to music or searching for a star. They were surprised to find the two networks merged together in children.
Kids don't just know a lot less. They think differently. Okay, you already knew that. But it is still great when science confirms our observations about human nature. Also, this sort of research is a useful lesson for those who try to force kids to act like adults.
A new brain scanning method made this discovery possible.
Scientists used a new brain scanning technique called resting state functional connectivity MRI to identify the control networks. Instead of analyzing mental activity when a volunteer works on a cognitive task, the new technique scans their brains while they do nothing. The scans reveal changes in the levels of oxygen in blood flowing to different areas of the brain. Researchers interpret correlations in the rise and fall of blood oxygen to different brain areas during inactivity as a sign that those areas likely work together. In neuroscientist's terms, this means the regions have functional connectivity.
A team of researchers led by Petersen and M.D./Ph.D. student Nico Dosenbach analyzed scans of volunteers with an approach called graph theory. They represented various brain regions of interest as shapes, and when two regions met a threshold for functional connectivity, they drew a line between them. The two control networks were distinctly separate even when the connectivity threshold was set to a low level.
For the new study, scientists used the same techniques to analyze the brains of 210 children, adolescents and adults. They found the two control networks are merged in children but begin pulling apart in adolescents, establishing themselves as separate entities and becoming more complex.
Some people complain that adolescents are so weird. To those people I ask: How would you act if your brain was undergoing a major reorganization of how it controls itself?
The brain continues to change as we get older.
Fair notes that an interesting pattern emerged as scientists looked at their data from a big picture perspective.
"As we get older, connections that are getting weaker tend to be between brain regions located close to each other, while the connections that are getting stronger tend be those between regions that are far apart," he says.
I'm skeptical of claims that there's a single best standard for aesthetic issues. Given that humans differ so much in how their brains are wired up we should expect people to differ in their tastes in music, architecture, annoyance at noise, desire to drive fast, and in countless other ways. This isn't to argue that every state of mind is equally morally justifiable. Murderers aren't justified in murdering just because some might be wired up to strongly want to murder.
Brain research will eventually present challenges when some differences in values are found to derive from innate differences in brain architectures. Hard to argue that a disagreement is due to misunderstandings when the disagreement is the result of innate differences in how brains reason and form emotions.
Brain development research will probably change how we grant rights. Children have fewer rights (e.g. a very limited right to contract) in most societies. That's a recognition of the lower capacity of children to judge and to fulfill responsibilities. Well, once research can show that some fast developing 16 year olds have a greater capacity to evaluate and fulfill obligations in contracts than some 25 year olds why should all 25 year olds have more rights than all 16 year olds?
Instead of an all-or-little granting of rights might it make more sense to grant levels of rights and even categories of rights incrementally based on extent of cognitive capabilities? We lack the capability to measure small gradations in ability to respect rights or honor contracts. But that won't always be the case. I expect results of brain scans and other measurements of cognitive capability to some day get used by governments to determine when a person can get a driver's license, enlist in the military, or become an emancipated minor.
Is susceptibility to peer pressure identifiable in adolescents using brain scans? ("but mom, my weak brain connections made it impossible for me to say no")
WASHINGTON, DC July 26, 2007 – Brain regions that regulate different aspects of behavior are more interconnected in children with high resistance to peer influence than those with low resistance, according to a new study published in the July 25 issue of The Journal of Neuroscience.
"These findings may help develop more effective strategies to prevent the development of lifestyles of violence and crime,” says John Sweeney, PhD, Director of the Center for Cognitive Medicine at the University of Illinois at Chicago. Sweeney was not involved in this study.
In the new study, Tomas Paus, MD, PhD, at the University of Nottingham, and his colleagues used functional neuroimaging to scan adolescents while they watched video clips of neutral or angry hand and face movements. Previous research has shown that anger is the most easily recognized emotion.
Paus and his team observed 35 10-year-olds with high and low resistance to peer influence, as determined by a questionnaire. The researchers then showed the children video clips of angry hand movements and angry faces and measured their brain activity. They found that the brains of all children showed activity in regions important for planning and extracting information about social cues from movement, but the connectivity between these regions was stronger in children who were marked as less vulnerable to peer influence. These children were also found to have more activity in the prefrontal cortex, an area important for decision making and inhibition of socially inappropriate behavior.
Do stronger connections between these brain regions form as these children with weaker connections get older? Or perhaps do they remain more susceptible to peer pressure?
Do babies conceived during summer perform worse at cognitive tasks?
INDIANAPOLIS — Does the time of year in which a child is conceived influence future academic achievement? Yes, according to research by neonatologist Paul Winchester, M.D., Indiana University School of Medicine professor of clinical pediatrics. Dr. Winchester, who studied 1,667,391 Indiana students, presents his finding on May 7 at the Pediatric Academic Societies' annual meeting.
Dr. Winchester and colleagues linked the scores of the students in grades 3 through 10 who took the Indiana Statewide Testing for Educational Progress (ISTEP) examination with the month in which each student had been conceived. The researchers found that ISTEP scores for math and language were distinctly seasonal with the lowest scores received by children who had been conceived in June through August.
Why might children conceived in June through August have the lowest ISTEP scores? "The fetal brain begins developing soon after conception. The pesticides we use to control pests in fields and our homes and the nitrates we use to fertilize crops and even our lawns are at their highest level in the summer," said Dr. Winchester, who also directs Newborn Intensive Care Services at St. Francis Hospital in Indianapolis.
"Exposure to pesticides and nitrates can alter the hormonal milieu of the pregnant mother and the developing fetal brain," said Dr. Winchester. "While our findings do not represent absolute proof that pesticides and nitrates contribute to lower ISTEP scores, they strongly support such a hypothesis."
I can think of many other potential explanations. For example, maybe the babies conceived in the summer do not get enough vitamin D in the winter and this lack of vitamin D causes their brains to develop poorly when their brains are developing most rapidly. Maybe nutritional status matters more during later months of pregnancy.
Pesticides might also be upping the rate of premature births.
INDIANAPOLIS — The growing premature birth rate in the United States appears to be strongly associated with increased use of pesticides and nitrates, according to work conducted by Paul Winchester, M.D., professor of clinical pediatrics at the Indiana University School of Medicine. He reports his findings May 7 at the Pediatric Academic Societies' annual meeting, a combined gathering of the American Pediatric Society, the Society for Pediatric Research, the Ambulatory Pediatric Association and the American Academy of Pediatrics.
Dr. Winchester and colleagues found that preterm birth rates peaked when pesticides and nitrates measurements in surface water were highest (April-July) and were lowest when nitrates and pesticides were lowest (Aug.-Sept.).
A repeat of this experiment in other regions could control for the pesticide effect since not all areas of the United States have much agriculture. Also, growing season start dates and lengths differ by region. The effect of pesticides would start later and end earlier in Maine than in Missouri for example. We could also see a difference depending on the source of water supply. Water supplies probably vary considerably in their pesticide concentrations.
A professor at the University of Maryland Child Development Laboratory claims the short version of a gene involved in metabolism of neurotransmitter serotonin combined with stress creates a shy kid.
In a study published in the February issue of Current Directions in Psychological Science, Nathan Fox, professor and director of the Child Development Laboratory, and his team found that kids who are consistently shy while growing up are particularly likely to be raised by stressed-out parents, and to possess a genetic variant associated with stress sensitivity.
...
Like all genes, the particular serotonin-related gene examined in this study has 2 alleles, which can be long or short. The protein produced by the short form of the gene is known to predispose towards some forms of stress sensitivity.
Fox's research found that among children exposed to a mother's stress, it was only those who also inherited the short forms of the gene who showed consistently shy behavior.
"If you have two short alleles of this serotonin gene, but your mom is not stressed, you will be no more shy than your peers as a school age child," says Fox. "But we found that when stress enters the picture, the gene starts to show a strong relationship to the child's behavior," says Fox. "If you are raised in a stressful environment, and you inherit the short form of the gene, there is a higher likelihood that you will be fearful, anxious or depressed."
From this press release we do not know the sample size of his study. But his result is at least plausible.
Suppose this gene's short version works as advertised. When offspring genetic engineering becomes possible will prospective parents choose to make shyness a thing of the past? Will some future generation be anywhere between extroverted and extremely extroverted? If so, what will we lose? My guess is that governments will become more corrupt as people with genetically engineered lack of shyness feel less fear of getting held up to public condemnation.
As part of the University of Bristol Children Of The 90s project dietary information and child cognitive performance was checked for children in thousands of families (the news reports speak of 9000 families or 11,875 pregnant women - maybe the higher number includes multiple pregnancies from some of the women?) . Children whose mothers ate fish more than 3 times a week did better in tests of cognitive function.
Mothers who ate more seafood than the US guidelines (340 grams, or three portions a week) had children who were more advanced in development tests measuring fine motor, communication and social skills as toddlers, had more positive social behaviours and were less likely to have low verbal IQ scores at the age of eight. Those children whose mothers had eaten no fish were 28 per cent more likely to have poor communication skills at 18 months, 35 per cent more likely to have poor fine motor coordination at age three and a half, 44 per cent more likely to have poor social behaviour at age seven and 48 per cent more likely to have a relatively low verbal IQ at age eight, when compared with children of women who ate more than the US guidelines advised.
But did they test parental IQ? Or did they control for socio-economic status of the parents? (which would be a rough proxy for genetic differences)
The new findings suggest that, for developing brains, the risks of limiting seafood consumption outweigh the benefits of such a limit, the NIH's Joseph R. Hibbeln, MD, tells WebMD.
"Regrettably, these data indicate that the [FDA-EPA] advisory apparently causes the harm that it was intended to prevent, especially with regard to verbal development," Hibbeln says.
The FDA-EPA advisory is aimed at reducing mercury exposure. But you can avoid the mercury while still getting lots of omega 3 fatty acids by either eating low mercury fish or by taking fish oil capsules.
Avoid higher mercury fish from the top of the food chain.
The study supports the contrary advice, given by the Food Standards Agency in the UK, which backs fish as a healthy food. The FSA simply advises mothers to avoid shark, swordfish and marlin, and restrict their intake of tuna.
The new research into children’s behaviour and intelligence suggests that women who follow the US “advisory” issued in 2004 to limit consumption, or cut fish out of their diet altogether, may miss nutrients that the developing brain needs — and so harm their children.
The women filled out a seafood consumption questionnaire while pregnant.
At 32 weeks into their pregnancy, the women were asked to fill in a seafood consumption questionnaire. They were subsequently sent questionnaires four times during their pregnancy, and then up to eight years after the birth of their child. Researchers examined issues including the children's social and communication skills, their hand-eye coordination, and their IQ levels. As with any study based on self-reporting methods, however, the results cannot be considered entirely definitive.
What I want to know: Did the mothers who ate less fish have lower IQs than the mothers who ate more fish? In other words, did these researchers measure an effect of nutritional differences or of genetic differences?
We still do not know with certainty that omega 3 fatty acids help make babies smarter. But since there's a chance they might it seems prudent for women to eat very low mercury fish.
High Fish Consumption Raises Baby Intelligence But Mercury Lowers IQ Also see the US FDA table Mercury Levels in Commercial Fish and Shellfish.
Researchers at King's College London followed 1,000 people in New Zealand from birth to the age of 32.
A third of those who were maltreated had high levels of inflammation - an early indicator of conditions such as heart disease and diabetes.
...
They took blood samples to measure levels of C-reactive protein, fibrinogen and white blood cells - substances which are known to be associated with inflammation in the body.
Adult survivors of childhood maltreatment who appeared to be healthy were twice as likely to show clinically relevant levels of inflammation compared to those who had not been maltreated.
So you get abused as a kid. Bad enough. But then you go on to suffer more diseases when you get older. The suffering lasts a lifetime. How incredibly cruel.
Twenty years hence will cheap in-school testing of kids for elevated inflammation response get used to spot kids who might be getting abused at home?
The findings could explain why children who are abused show a higher incidence of conditions such as heart disease and diabetes as adults, the researchers say. Until now, it has not been clear exactly how early stress could cause these future health problems, says Andrea Danese, a psychiatrist at King's College London in the UK.
What is the mechanism? Do the various endocrine organs become more prone to turn on the inflammatory responses? Or does brain development in the abused alter in a way that makes the brain send out stress chemicals in potentially stressful situations? I'm going to guess that the latter mechanism is at least partially responsible because abuse of children makes them more prone to violence when they get older - especially if they have the right version of the gene for the mono-amine oxidase A enzyme.
This brings up another thought: Could people who have higher levels of stress-related inflammation indicators get trained by biofeedback or other means to reduce their inflammatory response? It might not be that easy. During childhood development cells throughout the body might have gotten their epigenetic state altered to make them more prone to inflammation response.
More generally: We need better ways to dampen down inflammation responses. We have lots of responses that have ceased to be adaptive in the modern environment. Ever been in an argument at work where you felt the "fight or flight" urge? That response is a maladaptive vestige of our evolutionary history. You might some day find youself in a situation where the adrenaline rush could help you survive. But in most cases the response just makes you age more rapidly.
More evidence that omega 3 fatty acids found in fish help with the development of baby brains:
Fish oil supplements given to pregnant mums boost the hand-eye coordination of their babies as toddlers, reveals a small study published ahead of print in the Archives of Disease in Childhood (Fetal and Neonatal Edition).
The researchers base their findings on 98 pregnant women, who were either given 4g of fish oil supplements or 4g of olive oil supplements daily from 20 weeks of pregnancy until the birth of their babies.
Only non-smokers and those who did not routinely eat more than two weekly portions of fish were included in the study. Eighty three mothers completed the study.
Once the children had reached two and a half years of age, they were assessed using validated tests to measure growth and development.
These included tests of language, behaviour, practical reasoning and hand-eye coordination. In all, 72 children were assessed (33 in the fish oil group and 39 in the olive oil group).
There were no significant overall differences in language skills and growth between the two groups of children
But those whose mothers had taken fish oil supplements scored more highly on measures of receptive language (comprehension), average phrase length, and vocabulary.
And children whose mothers had taken fish oil supplements scored significantly higher in hand-eye coordination than those whose mothers had taken the olive oil supplements.
The effect might be even stronger if the mothers on the fish oil supplements breast feed. Though some baby formula contains omega 3 fatty acid DHA.
You can read the full paper as a PDF document:
Our finding of enhanced eye and hand coordination with fish oil supplementation is plausible and consistent with previously reported benefits on visual function after postnatal n-3 PUFA supplementation in both preterm14 24 and term15 25 infants. Although the underlying mechanism is not understood, DHA is known to facilitate rapid phototransduction in the retinal membrane,26 and deficiencies are associated with reduced retinal function in infant primates.2 Furthermore, effects on visual evoked potential could indicate that DHA may also have an effect on the development of the visual cortex.27 Finally, improved stereoacuity in infants has been associated with LC PUFA formula supplementation28 and fish intake of lactating mothers.29
To our knowledge, only one other study has assessed the effects of supplementation with high-dose fish oil in pregnancy on cognitive development of the offspring. A randomised clinical trial by Helland et al9 involved 590 pregnant women who received fish oil at half the dose we used in this study, from 18 weeks’ gestation until 3 months post partum. No differences in development were observed in the 269 infants tested at 6 and 9 months; however, fish oil supplementation was associated with increased mental processing in children at age 4 years. Additionally, mental processing scores were significantly correlated with maternal intake of DHA in pregnancy after adjusting for potential confounding factors10; this is consistent with observed correlations of DHA (and EPA) intake with eye and hand coordination in this study.
Other studies have found positive relationships between n- 3 PUFAs at birth (principally DHA) and aspects of visual and neurological development, in either observational studies30–32 or intervention studies using much lower levels of supplementation. 11 12 33 Our findings suggest that detection of the potentially beneficial effects of DHA in pregnancy may require larger doses. Further, although it is difficult to directly extrapolate the pregnancy dosage to supplementation of the preterm infant, the doses in our study resulted in similar increases in cord blood levels of DHA to those achieved with the higher doses trialled in preterm infants.34
The researchers acknowledge that their study was too small to prove their conclusions. But they think their conclusions are consistent with other studies of the effects of omega 3 fatty acid DHA on brain development.
Women who want to give their offspring every advantage should consider regular salmon meals or high quality omega 3 fatty acid supplements while pregnant and while lactating and breast feeding. Also, if you use baby formula and if DHA fortification is optional in your legal jurisdiction look for the formula brands that have DHA added.
Dr Sarah-Jayne Blakemore of the University College London Institute of Cognitive Neuroscience has found from brain scans that when compared to adults kids from age 8 through the teen years use less of an area of the brain involved in empathy and emotional evaluation when making decisions about the reactions of themselves and others to future hypothetical situations.
Teenagers take less account than adults of people's feelings and, often, even fail to think about their own, according to a UCL neuroscientist. The results, presented at the BA Festival of Science today, show that teenagers hardly use the area of the brain that is involved in thinking about other people's emotions and thoughts, when considering a course of action.
Many areas of the brain alter dramatically during adolescence. One area in development well beyond the teenage years is the medial prefrontal cortex, a large region at the front of the brain associated with higher-level thinking, empathy, guilt and understanding other people's motivations. Scientists have now found that, when making decisions about what action to take, the medial prefrontal cortex is under-used by teenagers. Instead, a posterior area of the brain, involved in perceiving and imagining actions, takes over.
Kids are deficient in empathy and guilt because they haven't yet developed the brain areas needed to fully consider the effects of their actions on others.
Functional Magnetic Resonance Imaging (fMRI) brain scans done while adults and teenagers were asked the same questions showed a different pattern of brain activation in teenagers versus adults.
In the study, teenagers and adults were asked questions about the actions they would take in a given situation while their brains were being scanned using fMRI. For example, 'You are at the cinema and have trouble seeing the screen. Do you move to another seat?' A second set of questions asked what they would expect to happen as a result of a natural event eg. 'A huge tree comes crashing down in a forest. Does it make a loud noise?'
Although teenagers and adults chose similar responses, the medial pre-frontal cortex was significantly more active in adults than in teenagers when questioned about their intended actions. Teenagers, on the other hand, activated the posterior area of the brain known as the superior temporal sulcus – an area that's involved in predicting future actions based on past actions.
Adults can imagine emotional reactions more rapidly than teenagers can.
Participants aged eight to 36 years were asked how they would feel and how they would expect someone else to feel in a series of situations. Adults were far quicker than teenagers at judging emotional reactions – both how they would feel and how a third party might feel in a given situation. For example, "How would you feel if you were not allowed to go to your best friend's party?" or 'A girl has just had an argument with her best friend. How does she feel?"
Brains of kids undergo sharp growth spurts. Therefore the brain undergoes distinct stages of development.
"Whatever the reasons, it is clear that teenagers are dealing with, not only massive hormonal shifts, but also substantial neural changes. These changes do not happen gradually and steadily between the ages of 0–18. They come on in great spurts and puberty is one of the most dramatic developmental stages."
I'd like to see various types of criminals compared to a general adult population. Do some criminals lack fully developed medial prefrontal cortexes? Could neural growth hormones delivered in adolescence to juvenile delinquents steer them away from a life of crime?
"The superior temporal sulcus is usually used in making simple actions, or watching other people make actions," said Dr Blakemore. "We think adolescents are performing this task by simply thinking about the action they're going to take.
"The part of the brain that the adults are using more is involved in much higher level thinking, such as thinking about the consequences of your actions in terms of other peoples' emotions and feelings."
Basically, adults run more complex models of the world that take into account more factors. They also experience feelings resulting from their internal mental simulations of the world and those feelings temper their actions.
Blakemore thinks the law should take into account differences in stages of brain development (and FuturePundit agrees).
The work has implications for the types of responsibility given to adolescents, Blakemore says: “Teenager’s brains are a work in progress and profoundly different from adults. If you’re making decisions about how to treat teenagers in terms of the law, you need to take this new research into account.”
Brains go through quite a transformation in the adolescent years. Kids are not just surly, sullen, rude, cruel, unhappy, and insensitive because they are sexually frustrated or resentful of their low status. Their ability to read the emotions in the faces of others even dips sharply starting around the age of 11. See my post Adolescence Is Tough On The Brain.
Youth with superior IQ are distinguished by how fast the thinking part of their brains thickens and thins as they grow up, researchers at the National Institutes of Health's (NIH) National Institute of Mental Health (NIMH) have discovered. Magnetic resonance imaging (MRI) scans showed that their brain's outer mantle, or cortex, thickens more rapidly during childhood, reaching its peak later than in their peers — perhaps reflecting a longer developmental window for high-level thinking circuitry. It also thins faster during the late teens, likely due to the withering of unused neural connections as the brain streamlines its operations. Drs. Philip Shaw, Judith Rapoport, Jay Giedd and colleagues at NIMH and McGill University report on their findings in the March 30, 2006 issue of Nature.
"Studies of brains have taught us that people with higher IQs do not have larger brains. Thanks to brain imaging technology, we can now see that the difference may be in the way the brain develops," said NIH Director Elias A. Zerhouni, M.D.
Here is where political correctness enters in. Zerhouni holds a highly visible position as head of a large government research agency. So in today's intellectual environment we can't expect much from him on the topic of intelligence. There is a positive correlation between IQ and brain size. There's an even higher positive correlation between IQ and brain gray matter size. But when it comes to differences in intelligence the taboos kick in with a vengeance. See links below for the truth of the matter.
While most previous MRI studies of brain development compared data from different children at different ages, the NIMH study sought to control for individual variation in brain structure by following the same 307 children and teens, ages 5-19, as they grew up. Most were scanned two or more times, at two-year intervals. The resulting scans were divided into three equal groups and analyzed based on IQ test scores: superior (121-145), high (109-120), and average (83-108).
The researchers found that the relationship between cortex thickness and IQ varied with age, particularly in the prefrontal cortex, seat of abstract reasoning, planning, and other "executive" functions. The smartest 7-year-olds tended to start out with a relatively thinner cortex that thickened rapidly, peaking by age 11 or 12 before thinning. In their peers with average IQ, an initially thicker cortex peaked by age 8, with gradual thinning thereafter. Those in the high range showed an intermediate trajectory (see below). While the cortex was thinning in all groups by the teen years, the superior group showed the highest rates of change.
"Brainy children are not cleverer solely by virtue of having more or less gray matter at any one age," explained Rapoport. "Rather, IQ is related to the dynamics of cortex maturation."
The observed differences are consistent with findings from functional magnetic resonance imaging, showing that levels of activation in prefrontal areas correlates with IQ, note the researchers. They suggest that the prolonged thickening of prefrontal cortex in children with superior IQs might reflect an "extended critical period for development of high-level cognitive circuits." Although it's not known for certain what underlies the thinning phase, evidence suggests it likely reflects "use-it-or-lose-it" pruning of brain cells, neurons, and their connections as the brain matures and becomes more efficient during the teen years.
The development of higher intellectual abilities required longer childhoods for humans than for other primates. Therefore it is not surprising that those who are smartest have longer periods of brain development.
"People with very agile minds tend to have a very agile cortex," said Shaw. The NIMH researchers are following-up with a search for gene variants that might be linked to the newly discovered trajectories. However, Shaw notes mounting evidence suggesting that the effects of genes often depends on interactions with environmental events, so the determinants of intelligence will likely prove to be a very complex mix of nature and nurture.
I'd really like to see a massive search for the genetic variations that boost intelligence. Identification of those genetic variations will lead to identification of targets for drug development and other means for boosting IQ in children whose brains are still developing.
As for the claim above that IQ does not correlate with brain size: Studies of brain size and intelligence have found correlations around r = 0.4. One study found that after controlling for body size the correlation with brain size was 0.65. Wikipedia has a short survey of brain size and IQ research results.
Modern studies using MRI imaging shows a weak to moderate correlation between brain size and IQ (Harvey, Persaud, Ron, Baker, & Murray, 1994) and have shown that brain size correlates with IQ by a factor of approximately .40 among adults (McDaniel, 2005). In 1991, Willerman et al. used data from 40 White American university students and reported a correlation coefficient of .35. Other studies done on samples of Caucasians show similar results, with Andreasen et al (1993) determining a correlation of .38[1], while Raz et al (1993) obtained a figure of .43 and Wickett et al. (1994) obtained a figure of .40. The correlation between brain size and IQ seems to hold for comparisons between and within families (Gignac et al. 2003; Jensen 1994; Jensen & Johnson 1994). However, one study found no within family correlation (Schoenemann et al. 2000).
The brain is a metabolically expensive organ, and consumes about 25% of the body's metabolic energy. Because of this fact, although larger brains are associated with higher intelligence, smaller brains might be advantageous from an evolutionary point of view if they are equal in intelligence to larger brains. Skull size correlates with brain size, but is not necessarily indicative.
The metabolic expense of the brain is the reason why brain size positively correlates with intelligence. Calorie malnutrition has been one of the biggest causes of death of humans since humans came into existence. The cost of a larger brain is such that it will get selected against unless it provides a selective advantage. Therefore it seems unreasonable to expect no correlation between brain size and intelligence.
P. Tom Schoenemann, an anthropologist at UC Berkeley, had this to say about brain size and IQ:
More interestingly, 4 recent studies of this question for the first time derived estimates of brain size from high quality magnetic resonance imaging (MRI), instead of using external cranial dimensions. All 4 studies show much higher correlations: Willerman et al. (1991) report an estimated correlation of r = .35 (N = 40); Andreasen et al. (1993) found a correlation of r= .38 (N = 67); Raz et al (in press) found a correlation of r = .43 (N = 29); and Wickett et al. (in press) report a correlation of r = .395 (N = 40, all females). These are all statistically significant. It is quite simply a myth that brain size and IQ are empirically unrelated in modern populations.
But it is a popular myth among public intellectuals.
Also see my post Brain Gray Matter Size Correlated To Intelligence.
Update: The New York Times coverage by Nicholas Wade notes that Dr. Paul Thompson of UCLA also found in 2001 that frontal lobes gray matter volume correlates with IQ.
In 2001, Dr. Thompson reported that based on imaging twins' brains the volume of gray matter in the frontal lobes and other areas correlated with I.Q. and was heavily influenced by genetics.
Wade also reports that the team around Shaw is doing many genetic studies on intelligence and have taken genetic samples from the Bethesda children used in this study.
But the researchers do not explain what goes wrong later. Kids start out on the road to science and enlightenment.
Even preschoolers approach the world much like scientists: They are convinced that perplexing and unpredictable events can be explained, according to an MIT brain researcher's study in the April issue of Child Development.
The way kids play and explore suggests that children believe cause-and-effect relationships in the world are governed by fundamental laws rather than by mysterious forces, said Laura E. Schulz, assistant professor of cognitive science and co-author of the study "God Does Not Play Dice: Causal Determinism and Preschoolers' Causal Inferences."
"It's important to understand that kids are approaching the world with deep assumptions that affect their actions and their explanations and shape what they're able to learn next," Schulz said. "Kids' fundamental beliefs affect their learning. Their theoretical framework affects their understanding of evidence, just as it does for scientists."
Kids believe in cause and effect.
Schulz and colleague Jessica Sommerville of the University of Washington tested 144 preschoolers to look at whether children believe that causes always produce effects. If a child believes causes produce effects deterministically, then whenever causes appear to work only some of the time, children should think some necessary cause is missing or an inhibitory cause is present.
In one study, the experimenters showed children that a switch made a toy with a metal ring light up. Half the children saw the switch work all the time; half saw that the switch only lit the ring toy some of the time. The experimenters also showed the children that removing the ring stopped the toy from lighting up. The experimenters kept the switch, gave the toy to the children and asked the children to stop the toy from lighting up.
If the switch always worked, children removed the ring. If the switch only worked some of the time, children could have removed the ring but they didn't--they assumed that the experimenter had some additional sneaky way of stopping the effect. Children did something completely new: They picked up an object that had been hidden in the experimenter's hand (a squeezable keychain flashlight) and used that to try to stop the toy. That is, the children didn't just accept that the switch might work only some of the time. They looked for an explanation.
They also figured out that adults are crafty and tricky. I wonder how old they were when they figured that out.
Perhaps the most startling finding was that the children of those women who had consumed the smallest amounts of omega-3 fatty acids during their pregnancies had verbal IQs six points lower than average. That may not sound much, but it would have a serious effect on a country's brainpower if it were widespread. And the finding is particularly pertinent because existing dietary advice to pregnant women, at least in America, is that they should limit their consumption of seafood in order to avoid exposing their fetuses to trace amounts of brain-damaging methyl mercury. Ironically, that means they avoid one of the richest sources of omega-3s.
Dr Hibbeln, however, says his work shows that the benefits of eating such fish vastly outweigh the risks from the mercury in them. Indeed, in the Avon study, it was those children exposed to the lowest levels of methyl mercury who were at greatest risk of having low verbal IQ.
Higher omega 3 fatty acid consumption was positively correlated with better fine motor performance and negatively correlated with pathological social behavior.
One obvious question: Are smarter women more atune to popular dietary advice and hence more likely to eat fish? That could explain at least part of the results in this study. Maybe the fish eating is just a proxy for having higher IQ genes to pass on to one's children. However, other studies support the argument that omega 3 fatty acid consumption improves brain development and brain performance.
Read the whole article.
Aside: I use a margarine substitute that contains a decent amount of omega 3 fatty acids and no trans fatty acids. Keep an eye out for such products if you want to boost your omega 3 fatty acid consumption but don't want to eat fish all that often.
Social and economic circumstances do not explain why twins have significantly lower IQ in childhood than single-born children, according to a study in this week's BMJ.
Researchers studied 9,832 single-born children and 236 twins born in Aberdeen, Scotland between 1950 and 1956, using a previous child development survey as a base. They also gathered further information on mother's age at delivery, birth weight, at what stage of the child's gestation they were born, their father's occupational social class, and information on other siblings.
They found that at age seven, the average IQ score for twins was 5.3 points lower than that for single-born children of the same family, and 6.0 points lower at age nine.
The study also showed that taking into account factors such as the child's sex, mother's age, and number of older siblings made little difference to the IQ gap.
Despite advances in recent years in obstetric practice and neonatal care, the authors argue that the likely explanation is because some twins have a shorter length of time in the womb than other children and are prone to impaired fetal growth.
I've been expecting this finding for years. It makes perfect sense. Mom can't feed two fetuses as well as she can feed one. I wonder if diet and perhaps exercise could at least partially compensate for this effect.
I also wonder if the use of drugs to prolong pregnancy could raise average IQ. If pregnancies could be stretched out a few extra weeks would the resulting babies grow up to be smarter? Anything that could raise average IQ a few points would do more to boost economic growth and lower social pathologies than increased educational spending or the other typical liberal or free market libertarian nostrums.
Another point: IVF therapies ought to be aimed to reduce the odds of multiple fetus pregnancies. Each baby is going to pay a steep cognitive cost from not being the sole pregnancy.
While decay of myelin due to auto-immune damage is suspected as a cause of multiple sclerosis some UCLA researchers see a much wider role for insufficient myelination as a cause of a large assortment of mental and behavioral disorders.
New evidence points to production of myelin, a fatty insulation coating the brain's internal wiring, as a neural Achilles' heel early in life.
An upcoming application of a novel model of human brain development and degeneration pioneered by a UCLA neuroscientist identifies disruption of myelination as a key neurobiological component behind childhood developmental disorders and addictive behaviors.
Detailed in an article in press with the upcoming annual peer-reviewed publication Adolescent Psychiatry (Hillsdale, N.J.; The Analytic Press Inc.; 2005) the analysis suggests that many factors can disrupt myelination and contribute to or worsen disorders such as autism, attention deficit/hyperactivity disorder and schizophrenia.
Note above that problems with myelination may contribute to addictive behaviors and ADHD.
There's a vicious cycle aspect to this report. Due to insufficient myelination a kid could be more prone to use of addictive drugs. But then the use of the drugs could prevent the myelination process from proceeding. This reminds me of people I know who used a lot of drugs while teenagers who never seem to have grown up since then. Did their drug and alcohol use block their own brain's maturation?
In addition, the analysis suggests that alcohol and other drugs of abuse have toxic effects on the myelination process in some adolescents, contributing to poor treatment outcomes and exacerbating co-existing psychiatric disorders.
Author Dr. George Bartzokis, a professor of neurology at UCLA's David Geffen School of Medicine, concludes that the high incidence of impulsive behaviors that characterize the teen years as well as many psychiatric disorders that occur in the teens and 20s are related to incomplete myelination of inhibitory "stop" brain circuits, while the "go" circuits become fully functional earlier in development. These inhibitory circuits are not on line to quickly interrupt high-risk behaviors that are so prevalent in teens and young adults.
If memory serves the development of the inhibitory circuits does not complete until about age 25. As a consequence of blocked myelin formation are heavy adolescent drug users more prone to impulsive, self-destructive, and violent behaviors even as adults?
There's an aging angle to myelination and demyelination.
"Myelination, a process uniquely elaborated in humans, arguably is the most important and most vulnerable process of brain development as we mature and age," said Bartzokis, who directs the UCLA Memory Disorders and Alzheimer's Disease Clinic and the Clinical Core of the UCLA Alzheimer's Disease Research Center.
"Environmental toxins, genetic predispositions and even diet appear to influence and sometimes disrupt this process," he added. "By shifting our research focus to medications that act on brain metabolism and development, as opposed to brain neurotransmitter chemistry, neuroscientists will likely find a wealth of novel opportunities for addressing the cause of brain disease rather than simply the symptoms."
Myelin is a sheet of lipid, or fat, with very high cholesterol content — the highest of any brain tissue. The high cholesterol content allows myelin to wrap tightly around axons, speeding messages through the brain by insulating these neural "wire" connections.
Bartzokis' analysis of magnetic resonance images and post-mortem tissue data suggests that the production of myelin is a key component of brain development through childhood and well into middle age, when development peaks and deterioration begins (Neurobiology of Aging, January 2004). He also identifies the midlife breakdown of myelin as a key to onset of Alzheimer's disease later in life (Archives of Neurology, March 2003; Neurobiology of Aging, August 2004).
We need rejuvenation therapies that will repair and replace aging myelin sheaths in the brain. Sign me up. I want rejuvenated myelin. Myelin rejuvenation no doubt will be part of the Strategies for Engineered Negligible Senescence (SENS) treatments.
Imagine a future two or three decades hence where parents take their kids in for cell therapies and gene therapies to make their myelin sheaths grow over their inhibitory circuitry more rapidly. Such therapies would reduce adolescent deaths from car accidents and from murder. Plus, the therapies would also reduce adolescent use of destructive drugs.
Adolescent rashness might have been selected for so that males in particular would compete more aggressively for mates. The slow myelination of inhibitory brain circuits might be an obsolete and maladaptive left-over consequence of evolution by natural selection.
Trained musicians are better at detecting differences in syllable sounds.
In two Stanford studies, researchers demonstrated that people with musical experience found it easier than non-musicians to detect small differences in word syllables. They also discovered that musical training helps the brain work more efficiently in distinguishing split-second differences between rapidly changing sounds that are essential to processing language.
Nadine Gaab, a former Stanford postdoctoral fellow, will present the findings at 9:30 a.m. Nov. 16 at the Society for Neuroscience's annual meeting in Washington, D.C. "These results have important potential implications for improving speech processing in children struggling with language and reading skills," she said. They also could help "seniors experiencing a decline in their ability to pick up rapid changes in the pitch and timing of sounds, as well as speech perception and verbal memory skills, and even for people learning a second language."
But does musical training really help language skills development all that much? The problem with this study (and with most social science for that matter) is that it compares people at a snapshot point. All sorts of selection effects could be responsible for this result.
Adults with and without musical training were compared in their ability to recognize syllable sequences.
In the first study, researchers took 28 adults, divided into musicians and non-musicians, who were matched for age, gender, intelligence and general language ability. Musicians in the study were required to have started playing an instrument before the age of 7, to have never stopped playing and to have continued to play several hours a week. When musicians play, Gaab said, they must actively distinguish between sounds and their order, and adjust as necessary.
Suppose a large cohort of 7 year olds were tested for general intelligence and language skills and then some proceeded to learn music an others did not. Would the music learners be better at understanding and speaking language 20 years later? I'm skeptical.
Non-musicians in the study had to be native English speakers with minimal experience studying non-tonal foreign languages such as Spanish. People who had studied a tonal language such as Mandarin were not included.
During the experiment, participants listened to pairs of syllables such as ba-da, ba-wa and ga-ka, and noted if each syllable in the pair sounded the same or different. Depending on how they performed, the scientists made the task increasingly difficult by using syllables that sounded more and more alike. Musicians outperformed their non-musician peers in how quickly and accurately they perceived these rapid changes, Gaab said.
In the second experiment, researchers used functional magnetic resonance imaging (fMRI) to find out whether musical training changes the way the brain processes sound. The fMRI scanning machines, which look like beds that slide into tubes, normally are used to check for brain injuries or tumors. With slightly different software they can be used to measure which regions of the brain are active by looking for changes in blood oxygenation, a process that occurs in parts of the brain where the neurons are active.
Forty people, evenly divided into musicians and non-musicians, listened to three-tone sequences made from different combinations of low and high pitches. Participants had to reproduce the order of the tones they heard by manually pressing buttons on a panel.
Musicians once again beat the non-musicians with this task. "We were surprised that musicians could do it almost perfectly," Gaab said. Musicians got the fastest tone sequences right at least 85 percent of the time, compared to non-musicians who hit a 50-percent average. They also could replicate the sequences a lot faster. "Non-musicians needed to make a lot more effort—their brains were not as finely attuned."
According to Gaab, musical training appears to alter the ability of the brain's language areas to process pitch and timing changes that are common to perceiving both words and music. "The brain becomes more efficient and can process more subtle auditory cues that occur simultaneously," she said.
I see these results as analogous to how a doctor or nurse has a fingertip that is very good at measuring a pulse. The ability measured is fairly narrow. A person who learns music might be better able to distinguish syllables and words which are mumbled or spoken quietly or spoken with an acccent or under noisy conditions. The effect would be equivalent to simply having better hearing. But the benefit might be limited to just an enhanced ability to signal process sounds and may not carry over at all into enhanced ability to parse sentences and understand, say, written language.
I've long wondered how much the learning of particular skills enhance or interfere with the ability to learn other skills. For example, learning math enables the learning of physics, engineering, andd sciences because it provides a conceptual toolbox needed to understand many other subjects. But does, say, learning foreign languages use up neuons that then are unavailable for learning other subjects? Or if a person is born blind does that person have more mental resources available to learn, say, spoken languages because their mind is not cluttered by visual image information? Do parts of their brain which otherwise would have been recruited for processing images instead get recruited for better processing of sounds?
Kids from Russian and Romanian orphanages have lower levels of hormones involved in bonding.
Crucial to making the link between social behavior and hormones was the work of co-author Toni Ziegler, an endocrinologist at the UW-Madison National Primate Research Center, who developed a technique that enables researchers to track vasopressin and oxytocin levels through the analysis of urine. The procedure is far less invasive than the existing method of analyzing blood or cerebrospinal fluid, and may one day find applications in several areas of child research such as the field of autism, Ziegler says.
The UW-Madison scientists worked with 18 four-year-old children who had lived in Russian and Romanian orphanages before being adopted into homes in the Milwaukee area. Despite the fact that the children now live in stable homes - for over three years, in some cases - they might still display some of the telltale behaviors that researchers have come to associate with early neglect. The abnormal willingness of a child to seek comfort from unfamiliar adults, even in the presence of the adopted parent, is one common instance of such behavior, says Wismer Fries.
Before starting her experiment, Wismer Fries collected urine samples from the young subjects to track baseline levels of vasopressin and oxytocin. Immediately, the scientists noticed that the children who experienced early neglect had markedly lower levels of vasopressin than the control group of non-adopted children. Researchers believe that vasopressin is essential for recognizing individuals in a familiar social environment. Lower levels of the hormone, Pollak says, may point to the social deprivation these children endured early on.
During the experiment, study subjects sat on the laps of either their mother or an unfamiliar woman and participated in an animated interactive computer game. The 30-minute game directed the children to engage in various types of physical contact with the adult they were sitting with, such as whispering or tickling each other, and patting each other on the head. When the game ended, Wismer Fries collected another urine sample from each child.
The UW-Madison researchers expected to see a hormonal response in the children following the physical contact with their mothers. And predictably, oxytocin levels rose in family-reared subjects. Yet, levels stayed the same among the previously neglected group. That result may help explain the difficulties many of these children have in forming secure relationships, the UW-Madison scientists say.
An obvious long term question needs answering: Do oxytocin and vasopressin levels of neglected kids eventually converge with levels found in normal kids of the neglected kids are adopted into stable homes? What happens after 10 or 15 years? Are these kids permanently tweaked?