1. Study suggests smart people have better connected brains

    December 4, 2017 by Ashley

    From the Goethe University Frankfurt press release:

    Differences in intelligence have so far mostly been attributed to differences in specific brain regions. However, are smart people’s brains also wired differently to those of less intelligent persons? A new study supports this assumption. In intelligent persons, certain brain regions are more strongly involved in the flow of information between brain regions, while other brain regions are less engaged.

    Understanding the foundations of human thought is fascinating for scientists and laypersons alike. Differences in cognitive abilities — and the resulting differences for example in academic success and professional careers — are attributed to a considerable degree to individual differences in intelligence. A study just published in Scientific Reports shows that these differences go hand in hand with differences in the patterns of integration among functional modules of the brain. Kirsten Hilger, Christian Fiebach and Ulrike Basten from the Department of Psychology at Goethe University Frankfurt combined functional MRI brain scans from over 300 persons with modern graph theoretical network analysis methods to investigate the neurobiological basis of human intelligence.

    Already in 2015, the same research group published a meta-study in the journal Intelligence, in which they identified brain regions — among them the prefrontal cortex — activation changes of which are reliably associated with individual differences in intelligence. Until recently, however, it was not possible to examine how such ‘intelligence regions’ in the human brain are functionally interconnected.

    Earlier this year, the research team reported that in more intelligent persons two brain regions involved in the cognitive processing of task-relevant information (i.e., the anterior insula and the anterior cingulate cortex) are connected more efficiently to the rest of the brain (2017, Intelligence). Another brain region, the junction area between temporal and parietal cortex that has been related to the shielding of thoughts against irrelevant information, is less strongly connected to the rest of the brain network. “The different topological embedding of these regions into the brain network could make it easier for smarter persons to differentiate between important and irrelevant information — which would be advantageous for many cognitive challenges,” proposes Ulrike Basten, the study’s principle investigator.

    In their current study, the researchers take into account that the brain is functionally organized into modules. “This is similar to a social network which consists of multiple sub-networks (e.g., families or circles of friends). Within these sub-networks or modules, the members of one family are more strongly interconnected than they are with people from other families or circles of friends. Our brain is functionally organized in a very similar way: There are sub-networks of brain regions — modules — that are more strongly interconnected among themselves while they have weaker connections to brain regions from other modules. In our study, we examined whether the role of specific brain regions for communication within and among brain modules varies with individual differences in intelligence, i.e., whether a specific brain region supports the information exchange within their own ‘family’ more than information exchange with other ‘families’, and how this relates to individual differences in intelligence.”

    The study shows that in more intelligent persons certain brain regions are clearly more strongly involved in the exchange of information between different sub-networks of the brain in order for important information to be communicated quickly and efficiently. On the other hand, the research team also identified brain regions that are more strongly ‘de-coupled’ from the rest of the network in more intelligent people. This may result in better protection against distracting and irrelevant inputs. “We assume that network properties we have found in more intelligent persons help us to focus mentally and to ignore or suppress irrelevant, potentially distracting inputs,” says Basten. The causes of these associations remain an open question at present. “It is possible that due to their biological predispositions, some individuals develop brain networks that favor intelligent behaviors or more challenging cognitive tasks. However, it is equally as likely that the frequent use of the brain for cognitively challenging tasks may positively influence the development of brain networks. Given what we currently know about intelligence, an interplay of both processes seems most likely.”


  2. Theory: Flexibility is at the heart of human intelligence

    by Ashley

    From the University of Illinois at Urbana-Champaign press release:

    Centuries of study have yielded many theories about how the brain gives rise to human intelligence. Some neuroscientists think intelligence springs from a single region or neural network. Others argue that metabolism or the efficiency with which brain cells make use of essential resources are key.

    A new theory, published in the journal Trends in Cognitive Sciences, makes the case that the brain’s dynamic properties — how it is wired but also how that wiring shifts in response to changing intellectual demands — are the best predictors of intelligence in the human brain.

    “When we say that someone is smart, we understand intuitively what that means,” said University of Illinois psychology professor Aron Barbey, the author of the new paper. “Usually, we’re referring to how good they are at making decisions and solving particular types of problems. But recently in neuroscience, there’s been a focus on understanding in biological terms how general intelligence arises.” That requires studying the structural and functional characteristics of the brain.

    Scientists have long understood that the brain is modular, with different regions supporting specific abilities, Barbey said.

    “For example, brain regions within the occipital lobe at the back of the brain are known to processes visual information,” he said. But interpreting what one sees requires the integration of information from other brain modules.

    “To identify an object, we also must classify it. That doesn’t depend only on vision. It also requires conceptual knowledge and other aspects of information processing, which are supported by other brain regions,” he said. “And as the number of modules increases, the type of information represented in the brain becomes increasingly abstract and general.”

    Scientists have struggled to understand how the brain organizes itself and have tried to identify a structure or region that performs that function.

    “The prefrontal cortex, a structure at the front of the brain, for example, has expanded dramatically over the course of human evolution,” Barbey said. Because this brain region is known to support several higher-order functions such as planning and organizing one’s behavior, scientists have suggested that the prefrontal cortex drives general intelligence.

    “But really, the entire brain — its global architecture and the interactions among lower- and higher-level mechanisms — is required for general intelligence,” Barbey said.

    Brain modules provide the basic building blocks from which larger, “intrinsic connectivity networks” are constructed, Barbey said. Each network includes multiple brain structures that are activated together when a person engages a particular cognitive skill.

    “For example, the frontoparietal network is activated when attention is focused on external cues, the salience network is engaged when attention is directed to relevant events, and the default mode network is recruited when attention is focused internally,” he said.

    Neural networks are made up of two types of connections that are believed to support two types of information processing, Barbey said.

    “There are the pathways that encode prior knowledge and experience, which we call ‘crystallized intelligence.’ And there are adaptive reasoning and problem-solving skills that are quite flexible, called ‘fluid intelligence,'” he said.

    Crystallized intelligence involves robust connections, the result of months or years of neural traffic on well-worn pathways. Fluid intelligence involves weaker, more transient pathways and connections that are formed when the brain tackles unique or unusual problems.

    “Rather than forming permanent connections, we are constantly updating our prior knowledge, and this involves forming new connections,” Barbey said. The more readily the brain forms and reforms its connectivity in response to changing needs, the better it works, he said.

    Although researchers have known that flexibility is an important characteristic of human brain function, only recently has the idea emerged that flexibility provides the basis for human intelligence, he said.

    “General intelligence requires both the ability to flexibly reach nearby, easy-to-access states — to support crystallized intelligence — but also the ability to adapt and reach difficult-to-access states — to support fluid intelligence,” Barbey said. “What my colleagues and I have come to realize is that general intelligence does not originate from a single brain region or network. Emerging neuroscience evidence instead suggests that intelligence reflects the ability to flexibly transition between network states.”


  3. Videogame study suggests link between intelligence and skill at game

    November 27, 2017 by Ashley

    From the University of York press release:

    Researchers at the University of York have discovered a link between young people’s ability to perform well at two popular video games and high levels of intelligence.

    Studies carried out at the Digital Creativity Labs (DC Labs) at York found that some action strategy video games can act like IQ tests. The researchers’ findings are published today in the journal PLOS ONE.

    The York researchers stress the studies have no bearing on questions such as whether playing computer games makes young people smarter or otherwise. They simply establish a correlation between skill at certain online games of strategy and intelligence.

    The researchers focused on ‘Multiplayer Online Battle Arenas’ (MOBAs) — action strategy games that typically involve two opposing teams of five individuals — as well as multiplayer ‘First Person Shooter’ games. These types of games are hugely popular with hundreds of millions of players worldwide.

    The team from York’s Departments of Psychology and Computer Science carried out two studies. The first examined a group of subjects who were highly experienced in the MOBA League of Legends — one of the most popular strategic video games in the world with millions of players each day.

    In this study, the researchers observed a correlation between performance in the strategic game League of Legends and performance in standard paper-and-pencil intelligence tests.

    The second study analysed big datasets from four games: Two MOBAs (League of Legends and Defence of the Ancients 2 (DOTA 2)) and two ‘First Person Shooters’ (Destiny and Battlefield 3). First Person Shooters (FPSs) are games involving shooting enemies and other targets, with the player viewing the action as though through the eyes of the character they are controlling.

    In this second study, they found that for large groups consisting of thousands of players, performance in MOBAs and IQ behave in similar ways as players get older. But this effect was not found for First Person Shooters, where performance declined after the teens.

    The researchers say the correlation between ability at action strategy video games such as League of Legends and Defence of the Ancients 2 (DOTA 2) and a high IQ is similar to the correlation seen in other more traditional strategy games such as chess.

    Corresponding author Professor Alex Wade of the University of York’s Department of Psychology and Digital Creativity Labs said: “Games such as League of Legends and DOTA 2 are complex, socially-interactive and intellectually demanding. Our research would suggest that your performance in these games can be a measure of intelligence.

    “Research in the past has pointed to the fact that people who are good at strategy games such as chess tend to score highly at IQ tests. Our research has extended this to games that millions of people across the planet play every day.”

    The discovery of this correlation between skill and intelligence opens up a huge new data source. For example, as ‘proxy’ tests of IQ, games could be useful at a global population level in fields such as ‘cognitive epidemiology’ — research that examines the associations between intelligence and health across time — and as a way of monitoring cognitive health across populations.

    Athanasios Kokkinakis, a PhD student with the EPSRC Centre for Intelligent Games and Game Intelligence (IGGI) research programme at York, is the lead author on the study.

    He said: “Unlike First Person Shooter (FPS) games where speed and target accuracy are a priority, Multiplayer Online Battle Arenas rely more on memory and the ability to make strategic decisions taking into account multiple factors.

    “It is perhaps for these reasons that we found a strong correlation between skill and intelligence in MOBAs.”

    Co-author Professor Peter Cowling, Director of DC Labs and the IGGI programme at York, said: “This cutting-edge research has the potential for substantial impact on the future of the games and creative industries — and on games as a tool for research in health and psychology.

    “The IGGI programme has 48 excellent PhD students working with industry and across disciplines — there is plenty more to come!”


  4. Study suggests visual intelligence is not the same as IQ

    November 17, 2017 by Ashley

    From the Vanderbilt University press release:

    Just because someone is smart and well-motivated doesn’t mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

    That is the implication of a new study which shows for the first time that there is a broad range of differences in people’s visual ability and that these variations are not associated with individuals’ general intelligence, or IQ. The research is reported in a paper titled “Domain-specific and domain-general individual differences in visual object recognition” published in the September issue of the journal Cognition and the implications are discussed in a review article in press at Current Directions in Psychological Science.

    “People may think they can tell how good they are at identifying objects visually,” said Isabel Gauthier, David K. Wilson Professor of Psychology at Vanderbilt University, who headed the study. “But it turns out that they are not very good at evaluating their own skills relative to others.”

    In the past, research in visual object recognition has focused largely on what people have in common, but Gauthier became interested in the question of how much visual ability varies among individuals. To answer this question, she and her colleagues had to develop a new test, which they call the Novel Object Memory Test (NOMT), to measure people’s ability to identify unfamiliar objects.

    Gauthier first wanted to gauge public opinions about visual skills. She did so by surveying 100 laypeople using the Amazon Mechanical Turk crowdsourcing service. She found that respondents generally consider visual tasks as fairly different from other tasks related to general intelligence. She also discovered that they feel there is less variation in people’s visual skills than there is in non-visual skills such as verbal and math ability.

    The main problem that Gauthier and colleagues had to address in assessing individuals’ innate visual recognition ability was familiarity. The more time a person spends learning about specific types of objects, such as faces, cars or birds, the better they get at identifying them. As a result, performance on visual recognition tests that use images of common objects are a complex mixture of people’s visual ability and their experience with these objects. Importantly, they have proven to be a poor predictor of how well someone can learn to identify objects in a new domain.

    Gauthier addressed this problem by using novel computer-generated creatures called greebles, sheinbugs and ziggerins to study visual recognition. The basic test consists of studying six target creatures, followed by a number of test trials displaying creatures in sets of three. Each set contains a creature from the target group along with two unfamiliar creatures, and the participant is asked to pick out the creature that is familiar.

    Analyzing the results from more than 2000 subjects, Gauthier and colleagues discovered that the ability to recognize one kind of creature was well predicted by how well subjects could recognize the other kind, although these objects were visually quite different. This confirmed the new test can predict the ability to learn new categories.

    The psychologists also used performance on several IQ-related tests and determined that the visual ability measured on the NOMT is distinct from and independent of general intelligence.

    “This is quite exciting because performance on cognitive skills is almost always associated with general intelligence,” Gauthier said. “It suggests that we really can learn something new about people using these tests, over and beyond all the abilities we already know how to measure.” Although the study confirms the popular intuition that visual skill is different from general intelligence, it found that individual variations in visual ability are much larger than most people think. For instance, on one metric, called the coefficient of variation, the spread of people was wider on the NOMT than on a nonverbal IQ test.

    “A lot of jobs and hobbies depend on visual skills,” Gauthier said. “Because they are independent of general intelligence, the next step is to explore how we can use these tests in real-world applications where performance could not be well predicted before.”


  5. Study debunks myth of OCD linkage to superior intelligence

    September 28, 2017 by Ashley

    From the American Associates, Ben-Gurion University of the Negev press release:

    Obsessive-compulsive disorder (OCD) is not associated with a higher intelligence quotient (IQ), a myth popularized by Sigmund Freud, according to researchers at Ben-Gurion University of the Negev (BGU), Texas State University and University of North Carolina at Chapel Hill.

    The study, published in the Neuropsychology Review, is believed to be the first analysis of existing data on the link between IQ and OCD sufferers verses the general population. The authors tracked the origins of the myth to the French philosopher, physician and psychologist Pierre Janet in 1903, but it was Freud, the father of psychoanalysis, who popularized the hypothesis in 1909.

    “Although this myth was never studied empirically until now, it is still a widely held belief among mental-health professionals, OCD sufferers and the general public,” says Dr. Gideon Anholt, a senior lecturer in BGU’s Department of Psychology.

    The researchers conducted a meta-analysis of all the available literature on IQ in OCD samples versus non-psychiatric controls (98 studies), and found that contrary to the prevailing myth, OCD is not associated with superior IQ, but with normative IQ that is slightly lower compared to control samples. The authors suggested that the small reduction in IQ scores in OCD sufferers may be largely attributed to OCD-related slowness and not to intellectual ability.

    The popular misconception about OCD has been further promoted by TV programs like “Monk,” which show an individual with OCD using his superior intelligence to solve challenging mysteries. Yet, such beliefs about OCD may facilitate the misconception that there are advantages associated with the disorder, potentially decreasing one’s motivation to seek professional help.

    “Future IQ assessments of individuals with OCD should focus on verbal and not performance IQ — a score heavily influenced by slowness,” the researchers say.

    The research team also included Dr. Amitai Abromovich, Texas State University; Sagi Raveh-Gottfried, psychology department, BGU; Dr. Jonathan S. Abramowitz, University of North Carolina at Chapel Hill; and Naama Hamo, Ruppin Academic Center, Israel.


  6. Higher IQ in childhood is linked to a longer life

    July 20, 2017 by Ashley

    From the BMJ press release:

    Higher intelligence (IQ) in childhood is associated with a lower lifetime risk of major causes of death, including heart disease, stroke, smoking related cancers, respiratory disease and dementia, finds a study published by The BMJ today.

    It is the largest study to date reporting causes of death in men and women across the life course, and the findings suggest that lifestyle, especially tobacco smoking, is an important component in the effect of intelligence on differences in mortality.

    Previous studies have shown that, on average, individuals with higher IQs tend to live a little longer than those with lower IQs, but these are largely based on data from male conscripts followed up only to middle adulthood.

    So a team of researchers from the University of Edinburgh set out to examine the association between intelligence test scores measured at age 11 and leading causes of death in men and women up to age 79.

    Their findings are based on data from 33,536 men and 32,229 women born in Scotland in 1936, who took a validated childhood intelligence test at age 11, and who could be linked to cause of death data up to December 2015.

    Cause of death included coronary heart disease, stroke, specific cancers, respiratory disease, digestive disease, external causes (including suicide and death from injury), and dementia.

    After taking account of several factors (confounders) that could have influenced the results, such as age, sex and socioeconomic status, the researchers found that higher childhood intelligence was associated with a lower risk of death until age 79.

    For example, a higher test score was associated with a 28% reduced risk of death from respiratory disease, a 25% reduced risk of death from coronary heart disease, and a 24% reduced risk of death from stroke.

    Other notable associations were seen for deaths from injury, smoking related cancers (particularly lung and stomach), digestive disease, and dementia. There was no evident association between childhood intelligence and death from cancers not related to smoking.

    The authors outline some study limitations which could have introduced bias. However, key strengths include the whole population sample, 68-year follow up, and ability to adjust for important confounders.

    They also point out that significant associations remained after further adjustment for smoking and socioeconomic status, suggesting that these factors did not fully account for mortality differences. And they say future studies “would benefit from measures of the cumulative load of such risk factors over the life course.”

    This study is the largest to date reporting causes of death across the life course, and it provides us with interesting results, say researchers based in Sweden, in a linked editorial.

    “Importantly, it shows that childhood IQ is strongly associated with causes of death that are, to a great extent, dependent on already known risk factors,” they write. And they suggest that “tobacco smoking and its distribution along the socioeconomic spectrum could be of particular importance here.”

    In conclusion, they say: “It remains to be seen if this is the full story or if IQ signals something deeper, and possibly genetic, in its relation to longevity.”


  7. Study suggests blood vessels in eye linked with IQ, cognitive function

    June 9, 2013 by Ashley

    From the Association for Psychological Science press release:

    senior man visionThe width of blood vessels in the retina, located at the back of the eye, may indicate brain health years before the onset of dementia and other deficits, according to a new study published in Psychological Science, a journal of the Association for Psychological Science.

    Research shows that younger people who score low on intelligence tests, such as IQ, tend to be at higher risk for poorer health and shorter lifespan, but factors like socioeconomic status and health behaviors don’t fully account for the relationship. Psychological scientist Idan Shalev of Duke University and colleagues wondered whether intelligence might serve as a marker indicating the health of the brain, and specifically the health of the system of blood vessels that provides oxygen and nutrients to the brain.

    To investigate the potential link between intelligence and brain health, the researchers borrowed a technology from a somewhat unexpected domain: ophthalmology.

    Shalev and colleagues used digital retinal imaging, a relatively new and noninvasive method, to gain a window onto vascular conditions in the brain by looking at the small blood vessels of the retina, located at the back of the eye. Retinal blood vessels share similar size, structure, and function with blood vessels in the brain and can provide a way of examining brain health in living humans.

    The researchers examined data from participants taking part in the Dunedin Multidisciplinary Health and Development Study, a longitudinal investigation of health and behavior in over 1000 people born between April 1972 and March 1973 in Dunedin, New Zealand.

    The results were intriguing.

    Having wider retinal venules was linked with lower IQ scores at age 38, even after the researchers accounted for various health, lifestyle, and environmental risk factors that might have played a role.

    Individuals who had wider retinal venules showed evidence of general cognitive deficits, with lower scores on numerous measures of neurospsychological functioning, including verbal comprehension, perceptual reasoning, working memory, and executive function.

    Surprisingly, the data revealed that people who had wider venules at age 38 also had lower IQ in childhood, a full 25 years earlier.

    It’s “remarkable that venular caliber in the eye is related, however modestly, to mental test scores of individuals in their 30s, and even to IQ scores in childhood,” the researchers observe.

    The findings suggest that the processes linking vascular health and cognitive functioning begin much earlier than previously assumed, years before the onset of dementia and other age-related declines in brain functioning.

    “Digital retinal imaging is a tool that is being used today mainly by eye doctors to study diseases of the eye,” Shalev notes. “But our initial findings indicate that it may be a useful investigative tool for psychological scientists who want to study the link between intelligence and health across the lifespan.”

    The current study doesn’t address the specific mechanisms that drive the relationship between retinal vessels and cognitive functioning, but the researchers surmise that it may have to do with oxygen supply to the brain.

    Increasing knowledge about retinal vessels may enable scientists to develop better diagnosis and treatments to increase the levels of oxygen into the brain and by that, to prevent age-related worsening of cognitive abilities,” they conclude.

     

     


  8. Study suggests IQ predicted by ability to filter motion

    May 27, 2013 by Ashley

    From the University of Rochester press release via EurekAlert!:

    mind mazeA brief visual task can predict IQ, according to a new study.

    This surprisingly simple exercise measures the brain’s unconscious ability to filter out visual movement. The study shows that individuals whose brains are better at automatically suppressing background motion perform better on standard measures of intelligence.

    The test is the first purely sensory assessment to be strongly correlated with IQ and may provide a non-verbal and culturally unbiased tool for scientists seeking to understand neural processes associated with general intelligence.

    “Because intelligence is such a broad construct, you can’t really track it back to one part of the brain,” says Duje Tadin, a senior author on the study and an assistant professor of brain and cognitive sciences at the University of Rochester. “But since this task is so simple and so closely linked to IQ, it may give us clues about what makes a brain more efficient, and, consequently, more intelligent.”

    The unexpected link between IQ and motion filtering was reported online in the Cell Press journal Current Biology on May 23 by a research team lead by Tadin and Michael Melnick, a doctoral candidate in brain and cognitive sciences at the University of Rochester.

    In the study, individuals watched brief video clips of black and white bars moving across a computer screen. Their sole task was to identify which direction the bars drifted: to the right or to the left. The bars were presented in three sizes, with the smallest version restricted to the central circle where human motion perception is known to be optimal, an area roughly the width of the thumb when the hand is extended. Participants also took a standardized intelligence test.

    As expected, people with higher IQ scores were faster at catching the movement of the bars when observing the smallest image. The results support prior research showing that individuals with higher IQs make simple perceptual judgments swifter and have faster reflexes. “Being ‘quick witted’ and ‘quick on the draw’ generally go hand in hand,” says Melnick.

    But the tables turned when presented with the larger images. The higher a person’s IQ, the slower they were at detecting movement. “From previous research, we expected that all participants would be worse at detecting the movement of large images, but high IQ individuals were much, much worse,” says Melnick. That counter-intuitive inability to perceive large moving images is a perceptual marker for the brain’s ability to suppress background motion, the authors explain. In most scenarios, background movement is less important than small moving objects in the foreground. Think about driving in a car, walking down a hall, or even just moving your eyes across the room. The background is constantly in motion.

    The key discovery in this study is how closely this natural filtering ability is linked to IQ. The first experiment found a 64 percent correlation between motion suppression and IQ scores, a much stronger relationship than other sensory measures to date. For example, research on the relationship between intelligence and color discrimination, sensitivity to pitch, and reaction times have found only a 20 to 40 percent correlation. “In our first experiment, the effect for motion was so strong,” recalls Tadin, “that I really thought this was a fluke.”

    So the group tried to disprove the findings from the initial 12-participant study conducted while Tadin was at Vanderbilt University working with co-author Sohee Park, a professor of psychology. They reran the experiment at the University of Rochester on a new cohort of 53 subjects, administering the full IQ test instead of an abbreviated version and the results were even stronger; correlation rose to 71 percent. The authors also tested for other possible explanations for their findings.

    For example, did the surprising link to IQ simply reflect a person’s willful decision to focus on small moving images? To rule out the effect of attention, the second round of experiments randomly ordered the different image sizes and tested other types of large images that have been shown not to elicit suppression. High IQ individuals continued to be quicker on all tasks, except the ones that isolated motion suppression. The authors concluded that high IQ is associated with automatic filtering of background motion.

    “We know from prior research which parts of the brain are involved in visual suppression of background motion. This new link to intelligence provides a good target for looking at what is different about the neural processing, what’s different about the neurochemistry, what’s different about the neurotransmitters of people with different IQs,” says Tadin.

    The relationship between IQ and motion suppression points to the fundamental cognitive processes that underlie intelligence, the authors write. The brain is bombarded by an overwhelming amount of sensory information, and its efficiency is built not only on how quickly our neural networks process these signals, but also on how good they are at suppressing less meaningful information. “Rapid processing is of little utility unless it is restricted to the most relevant information,” the authors conclude.

    The researchers point out that this vision test could remove some of the limitations associated with standard IQ tests, which have been criticized for cultural bias. “Because the test is simple and non-verbal, it will also help researchers better understand neural processing in individuals with intellectual and developmental disabilities,” says co-author Loisa Bennetto, an associate professor of psychology at the University of Rochester.


  9. Study suggests genetic schizophrenia risk linked to lower IQ among people who do not develop schizophrenia

    May 23, 2013 by Ashley

    From the Elsevier press release via EurekAlert!:

    mental healthThe relationship between the heritable risk for schizophrenia and low intelligence (IQ) has not been clear. Schizophrenia is commonly associated with cognitive impairments that may cause functional disability.

    There are clues that reduced IQ may be linked to the risk for developing schizophrenia. For example, reduced cognitive ability may precede the onset of schizophrenia symptoms. Also, these deficits may be present in healthy relatives of people diagnosed with schizophrenia.

    In a remarkable new study published in Biological Psychiatry, Dr. Andrew McIntosh and his colleagues at the University of Edinburgh provide new evidence that the genetic risk for schizophrenia is associated with lower IQ among people who do not develop this disorder.

    The authors analyzed data from 937 individuals in Scotland who first completed IQ testing in 1947, at age 11. Around age 70, they were retested and their DNA was analyzed to estimate their genetic risk for schizophrenia.

    The researchers found that individuals with a higher genetic risk for schizophrenia had a lower IQ at age 70 but not at age 11. Having more schizophrenia risk-related gene variants was also associated with a greater decline in lifelong cognitive ability.

    If nature has loaded a person’s genes towards schizophrenia, then there is a slight but detectable worsening in cognitive function between childhood and old age. With further research into how these genes affect the brain, it could become possible to understand how genes linked to schizophrenia affect people’s cognitive function,” said McIntosh.

    These findings suggest that common genetic variants may underlie both cognitive aging and risk of schizophrenia.

    “While this study does not show that these common gene variants produce schizophrenia per se, it elegantly suggests that these variants may contribute to declines in intelligence, a clinical feature associated with schizophrenia,” commented Dr. John Krystal, Editor of Biological Psychiatry. “However, we have yet to understand the development of cognitive impairments that produce disability in young adulthood, the period when schizophrenia develops for many affected people.”

    Clearly, more research is necessary, but this new study adds to the growing and substantial effort to understand how the gene variants that contribute to the development of schizophrenia give rise to the cognitive disability commonly associated with it.

     


  10. Study links flame retardants to hyperactivity, lower intelligence

    May 6, 2013 by Ashley

    From the University of Cincinnati press release via HealthCanal:

    lab_researchA new study led by researchers at the University of Cincinnati (UC) College of Medicine shows that prenatal exposure to chemical flame retardants used in everyday products such as baby strollers, carpeting and electronics is associated with hyperactivity and lower intelligence in early childhood.

    The research on the chemicals, known as polybrominated diphenyl ethers (PBDEs), is being presented Monday, May 6, at the Pediatric Academic Societies (PAS) annual meeting in Washington, D.C. The study’s lead author is Aimin Chen, MD, PhD, an assistant professor of environmental health at UC.

    “In animal studies, PBDEs can disrupt thyroid hormone and cause hyperactivity and learning problems,” says Chen. “Our study adds to several other human studies to highlight the need to reduce exposure to PBDEs in pregnant women.”

    Chen and his colleagues at UC collected blood samples from 309 pregnant women enrolled in a study at Cincinnati Children’s Hospital Medical Center to measure PBDE levels. They also performed intelligence and behavior tests on the women’s children annually until they were 5 years old.

    We found that maternal exposure to PBDEs, a group of brominated flame retardants mostly withdrawn from the U.S. market in 2004, was associated with deficits in child cognition at age 5 years and hyperactivity at ages 2 to 5 years,” Chen says. A 10-fold increase in maternal PBDEs was associated with about a four-point IQ deficit in 5-year-old children.

    Even though PBDEs, except Deca-BDEs, are not used as a flame retardant in the United States anymore, they are found on many consumer products bought several years ago. In addition, the chemicals are not easily biodegradable, so they remain in human tissues and are transferred to the developing fetus.

    Because PBDEs exist in the home and office environment as they are contained in old furniture, carpet pads, foams and electronics, the study raises further concern about their toxicity in developing children,” Chen says.