Chapter 13. Memory, Learning, and Development
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|By Michele Solis An individual with obsessive-compulsive disorder (OCD) is overcome with an urge to engage in unproductive habits, such as excessive hand washing or lock checking. Though recognizing these behaviors as irrational, the person remains trapped in a cycle of life-disrupting compulsions. Previous studies found that OCD patients have abnormalities in two different brain systems—one that creates habits and one that plays a supervisory role. Yet whether the anomalies drive habit formation or are instead a consequence of doing an action over and over remained unclear. To resolve this question, a team at the University of Cambridge monitored brain activity while people were actually forming new habits. Lapses in supervision are to blame, the researchers reported in a study published online in December 2014 in the American Journal of Psychiatry. They scanned 37 people with OCD and 33 healthy control subjects while they learned to avoid a mild shock by pressing on a foot pedal. Pressing the pedal became a habit for everyone, but people with OCD continued to press even when the threat of shock was over. Those with OCD showed abnormal activity in the supervisory regions important for goal-directed behavior but not in those responsible for habit formation. The finding suggests that shoring up the goal-directed systems through cognitive training might help people with OCD. The growing understanding of OCD's roots in the brain may also help convince individuals to engage in standard habit-breaking treatments, which expose a person to a trigger but prevent his or her typical response. “It's hard for people to not perform an action that their whole body is telling them to do,” says first author Claire Gillan, now at New York University. “So if you have an awareness that the habit is just a biological slip, then it makes OCD a lot less scary and something you can eventually control.” © 2015 Scientific American
By Aleksandra Sagan, CBC News In a Dutch town about 20 kilometres outside of Amsterdam, a small community lives in what at first glance seems like a real-life version of The Truman Show. Hogewey has a grocery store, a theatre and a barber shop. The only twist is that many of its 152 residents live unaware that their orderly community is actually a nursing home for people with severe dementia. "We protect our residents from the unsafe world. They do not understand the world outside this because the outside world doesn't understand them," says Yvonne van Amerongen, an employee at Hogewey who also helped develop the concept. Hogewey was officially opened in 2007, but the idea has now caught the attention of health-care professionals in Ontario and Alberta. Rhonda Desroches, who helped create a smaller-scale Hogewey in Penetanguishene, Ont., says relatives of the residents are pleased with how happy their family members seem to be in the new facility. Dementia is a growing problem. According to the Alzheimer Society Canada, one out of 20 Canadians over 65 has Alzheimer's Disease, and that figure jumps to one in four for Canadians over 85. In 2012, the World Health Organization declared dementia a public health priority. Many dementia patients move into nursing homes, where they are monitored in a safe setting. But some medical professionals want to shift patients away from unfamiliar, clinical settings and into spaces that resemble more typical surroundings. Hogewey creates a familiar, "normal" environment that dementia patients understand, says van Amerongen. The citizens of Hogewey share a house with about six others, and are classified according to one of seven lifestyles. ©2015 CBC/Radio-Canada
Link ID: 20875 - Posted: 05.04.2015
Neuroscientists have discovered brain circuitry for encoding positive and negative learned associations in mice. After finding that two circuits showed opposite activity following fear and reward learning, the researchers proved that this divergent activity causes either avoidance or reward-driven behaviors. Funded by the National Institutes of Health, they used cutting-edge optical-genetic tools to pinpoint these mechanisms critical to survival, which are also implicated in mental illness. “This study exemplifies the power of new molecular tools that can push and pull on the same circuit to see what drives behavior,” explained Thomas R. Insel, M.D., director of NIH’s National Institute of Mental Health (NIMH). “Improved understanding of how such emotional memory works holds promise for solving mysteries of brain circuit disorders in which these mechanisms are disrupted.” NIMH grantee Kay Tye, Ph.D. External Web Site Policy, Praneeth Namburi and Anna Beyeler, Ph.D., of the Massachusetts Institute of Technology (MIT), Cambridge, and colleagues, report their findings April 29, 2015 in the journal Nature. Prior to the new study, scientists suspected involvement of the circuits ultimately implicated, but were stumped by a seeming paradox. A crossroads of convergent circuits in an emotion hub deep in the brain, thebasolateral amygdala, seem to be involved in both fear and reward learning, but how one brain region could orchestrate such opposing behaviors – approach and avoidance – remained an enigma. How might signals find the appropriate path to follow at this fork in the road?
Children who were often bullied by their peers may experience more anxiety and depression than children who were abused by adults, a finding that U.S. and British researchers say highlights an "imbalance" in school services to tackle bullying. Researchers followed the mental health of more than 4,000 children in Avon, south west England from birth to age 18 and 1,400 others in North Carolina from age nine up to age 26 through parent questionnaires and clinical interviews. In the Avon study, maltreatment was defined as physical, emotional, or sexual abuse or "maladaptive parenting" such as hitting, shouting and hostility. Children were interviewed about the frequency of bullying, which included overt threats, physical violence and nasty names as well as social exclusion or spreading lies or rumours. The results consistently showed an increased risk of anxiety, depression, self-harm and suicidal tendencies in children who were bullied, whether or not they had a history of abuse by adults, Prof. William Copeland, a clinical psychologist at Duke University School of Medicine in Durham, N.C. and his co-authors concluded in Tuesday's issue of Lancet Psychiatry. "What was a surprise was to see [the results] were as significant and pervasive as what we see for children that are physically abused, sexually abused or neglected," Copeland said. Government policies have focused almost exclusively on providing services for child abuse but much less attention and resources are devoted to bullying, the researchers said. Copeland's previous research showed long-term repercussions from bullying persist — and that includes impacts on physical health, dropping out of school and trouble with authorities. ©2015 CBC/Radio-Canada
By Tina Hesman Saey People with depression have more mitochondrial DNA and shorter telomeres than nondepressed people do, an international team of researchers reports online April 23 in Current Biology. Mitochondria are organelles that produce energy for cells. Mitochondria seem to become inefficient under stress, the team found, so more mitochondria may be needed to produce enough energy. Telomeres are the DNA endcaps on chromosomes that prevent the genetic material from unraveling. Short telomeres are associated with shorter life spans. The altered DNA may reflect metabolic changes associated with depression, the researchers say. Experiments with mice showed that these DNA changes are brought on by stress or by stress hormones. Four weeks after scientists stopped stressing the mice, their mitochondrial and telomere DNA had returned to normal. Those results indicate that the molecular changes are reversible. Researchers also studied DNA from more than 11,000 people to learn whether past stress was responsible for the molecular changes seen in people with depression. Depression was associated with the DNA changes, but having a stressful life was not. For instance, people who had experienced childhood sexual abuse but were not depressed did not have statistically meaningful changes to their DNA compared with people who had no history of abuse. The findings suggest that stress can change DNA but many people can bounce back. Depressed people may have a harder time recovering from the molecular damage. © Society for Science & the Public 2000 - 2015.
Pete Etchells Over the past few years, there seems to have been a insidious pandemic of nonsense neuroscientific claims creeping into the education system. In 2013, the Wellcome Trust commissioned a series of surveys of parents and teachers, asking about various types of educational tools or teaching methods, and the extent to which they believe they have a basis in neuroscience. Worryingly, 76% of teachers responded that they used learning styles in their teaching, and a further 19% responded that they either use, or intend to use, left brain/right brain distinctions to help inform learning methods. Both of these approaches have been thoroughly debunked, and have no place in either neuroscience or education. In October last year, I reported on another study that showed that in the intervening time, things hadn’t really improved – 91% of UK teachers in that survey believed that there were differences in the way that students think and learn, depending on which hemisphere of the brain is ‘dominant’. And despite lots of great attempts to debunk myths about the brain, they still seem to persist and take up residence as ‘commonplace’ knowledge, being passed onto children as if they are fact. When I wrote about an ATL proposal to train teachers in neuroscience – a well-intended idea, but ultimately grounded in nonsense about left brain/right brain myths – I commented at the end that we need to do more to bring teachers and neuroscientists together, to discuss whether neuroscience has a relevant role in informing the way we teach students. Now, a new initiative funded by the Wellcome Trust is aiming to just that. © 2015 Guardian News and Media Limited
by Katie Collins Sarah-Jayne Blakemore is just as fascinated by the links between neuroscience and education as she is outraged by the pseudo science that often intrudes upon this territory. Neuroscience in education has really been flourishing in recent years, she says on stage at WIRED Health 2015, but some theories about neuroscience have already infiltrated schools, and not necessarily in a good way. Some products that makes claims about having a positive effect on cognition make bogus claims that may well have positive effects in the classroom, but at the same time promote completely inaccurate science. Blakemore points specifically to the Brain Gym educational model, which claims to improve memory, concentration and information retention. There are no problems with the exercises themselves, she says, but the claims made about the brain are baseless. For a start, she said, Brain Gym claims that children can push "brain buttons" on their bodies that will stimulate blood flow to the brain. Another physical exercise claimed to increase and improve connectivity between the two sides of the brain. "This makes no sense -- they are in communication anyway," says Blakemore. Teachers like Brain Gym because it does what it says and results in improvements in the classroom, but it could just as easily be placebo or novelty causing the effects. One thing Blakemore is sure of? "They're nothing to do with brain buttons or coordinating the two brain hemispheres."
Keyword: Development of the Brain
Link ID: 20844 - Posted: 04.25.2015
By Felicity Muth One of the first things I get asked when I tell people that I work on bee cognition (apart from ‘do you get stung a lot?’) is ‘bees have cognition?’. I usually assume that this question shouldn’t be taken literally otherwise it would mean that whoever was asking me this thought that there was a possibility that bees didn’t have cognition and I had just been making a terrible mistake for the past two years. Instead I guess this question actually means ‘please tell me more about the kind of cognitive abilities bees have, as I am very much surprised to hear that bees can do more than just mindlessly sting people’. So, here it is: a summary of some of the more remarkable things that bees can do with their little brains. In the first part of two articles on this topic, I introduce the history and basics of bee learning. In the second article, I go on to discuss the more advanced cognitive abilities of bees. The study of bee cognition isn’t a new thing. Back in the early 1900s the Austrian scientist Karl von Frisch won the Nobel Prize for his work with honeybees (Apis mellifera). He is perhaps most famous for his research on their remarkable ability to communicate through the waggle dance but he also showed for the first time that honeybees have colour vision and learn the colours of the flowers they visit. Appreciating how he did this is perhaps the first step to understanding everything we know about bee cognition today. Before delving into the cognitive abilities of bees it’s important to think about what kinds of abilities a bee might need, given the environment she lives in (all foraging worker bees are female). Bees are generalists, meaning that they don’t have to just visit one particular flower type for food (nectar and pollen), but can instead visit hundreds of different types. However, not all flowers are the same. © 2015 Scientific American,
By Maggie Fox Another study aimed at soothing the fears of some parents shows that vaccines don't cause autism. This one takes a special look at children with older siblings diagnosed with autism, who do themselves have a higher risk of an autism spectrum disorder. But even these high-risk kids aren't more likely to develop autism if they're vaccinated, according to the report in the Journal of the American Medical Association. "We found that there was no harmful association between receipt of the MMR (measles, mumps and rubella) vaccine and development of autism spectrum disorder," said Dr. Anjali Jain of The Lewin Group, a health consulting group in Falls Church, Virginia, who led the study. Kids who had older brothers or sisters with autism were less likely to be vaccinated on time themselves, probably because their parents had vaccine worries. But those who were vaccinated were no more likely than the unvaccinated children to develop autism, Jain's team found. Autism is very common. The Centers for Disease Control and Prevention says one in 68 U.S. kids has an autism spectrum disorder. Numbers have been growing but CDC says much of this almost certainly reflects more awareness and diagnosis of kids who would have been missed in years past.
Link ID: 20829 - Posted: 04.22.2015
The brains of babies “light up” in a similar way to adults when exposed to the same painful stimulus, suggesting they feel pain much like adults do, researchers said on Tuesday. In the first of its kind study using magnetic resonance imaging (MRI), scientists from Britain’s Oxford University found that 18 of the 20 brain regions active in adults experiencing pain were also active in babies. Brain scans of the sleeping infants while they were subjected to mild pokes on the bottom of their feet with a special rod – creating a sensation “like being poked with a pencil” – also showed their brains had the same response to a slighter “poke” as adults did to a stimulus four times as strong, suggesting babies have a much lower pain threshold. “Obviously babies can’t tell us about their experience of pain and it is difficult to infer pain from visual observations,” said Rebeccah Slater, a doctor at Oxford’s paediatrics department who led the study. “In fact some people have argued that babies’ brains are not developed enough for them to really feel pain ... [yet] our study provides the first really strong evidence this is not the case.” Even as recently as the 1980s it was common practice for babies undergoing surgery to be given neuromuscular blocks but no pain relief medication. Last year, a review of neonatal pain management in intensive care found that although these babies experience an average of 11 painful procedures per day, 60% do not receive any kind of pain medication. © 2015 Guardian News and Media Limited
By Alix Spiegel In 1979, when Jim Stigler was still a graduate student at the University of Michigan, he went to Japan to research teaching methods and found himself sitting in the back row of a crowded fourth-grade math class. “The teacher was trying to teach the class how to draw three-dimensional cubes on paper,” Stigler explains, “and one kid was just totally having trouble with it. His cube looked all cockeyed, so the teacher said to him, ‘Why don’t you go put yours on the board?’ So right there I thought, ‘That’s interesting! He took the one who can’t do it and told him to go and put it on the board.’ ” Stigler knew that in American classrooms, it was usually the best kid in the class who was invited to the board. And so he watched with interest as the Japanese student dutifully came to the board and started drawing, but still couldn’t complete the cube. Every few minutes, the teacher would ask the rest of the class whether the kid had gotten it right, and the class would look up from their work, and shake their heads no. And as the period progressed, Stigler noticed that he — Stigler — was getting more and more anxious. In Japanese classrooms, teachers consciously design tasks that are slightly beyond the capabilities of the students they teach, so the students can actually experience struggling with something just outside their reach. “I realized that I was sitting there starting to perspire,” he says, “because I was really empathizing with this kid. I thought, ‘This kid is going to break into tears!’ ” © 2015 KQED Inc.
Keyword: Learning & Memory
Link ID: 20820 - Posted: 04.20.2015
Mothers may influence the mood and behaviour of their babies through their breast milk, researchers say. There's growing evidence that mother's milk doesn't just affect the growth of a baby's body "but also areas of their brain that shape their motivations, their emotions, and therefore their behavioural activity," says Katie Hinde, an assistant professor of human evolutionary biology at Harvard University. In a paper published in the journal Evolution, Medicine and Public Health, Hinde and two other researchers propose a way in which the composition of breast milk could influence a baby's brain and behaviour. If food is scarce or there are a lot of predators around, it may be better for a mother to have a baby that is calmer and focuses on growing rather than one that is very active and playful, Hinde told CBC Radio's Quirks & Quarks in an interview that airs Saturday. It may be possible to influence a baby's activity level by changing the composition of the milk to affect the bacteria in the infant's gut, she added. Breast milk contains a lot of sugars that infants can't digest, but that feed bacteria that live in human intestines. Those bacteria don't just help digest food, said Hinde. "They can release chemical signals that travel to the infant's brain and shape neurodevelopment." ©2015 CBC/Radio-Canada
by Beth Mole Small doses of lead may have big impacts on reading and math scores, scientists report April 7 in Environmental Health. Researchers looked at third grade test scores and levels of lead in blood samples from 58,650 students in Chicago public schools. As little as 2 micrograms of lead per deciliter of blood was associated with lower reading and math scores. The Centers for Disease Control and Prevention recommends that anything above 5 micrograms per deciliter is of concern. The researchers estimate that childhood lead levels at or above 5 micrograms per deciliter of blood accounted for as many as 25 percent of the children in the study failing reading and math standardized tests. The findings confirm that lead exposure, even at low doses, is associated with poor school performance. © Society for Science & the Public 2000 - 2015
By Nicholas Bakalar Breathing problems during sleep may be linked to early mental decline and Alzheimer’s disease, a new study suggests. But treating apnea with a continuous positive airway pressure machine can significantly delay the onset of cognitive problems. In a group of 2,470 people, average age 73, researchers gathered information on the incidence of sleep apnea, a breathing disorder marked by interrupted breathing and snoring, and the incidence of mild cognitive impairment and Alzheimer’s disease. After adjusting for a range of variables, they found that people with disordered breathing during sleep became cognitively impaired an average of about 10 years sooner than those without the disorder. But compared with those whose sleep disorder was untreated, those using C.P.A.P. machines delayed the appearance of cognitive impairment by an average of 10 years — making their age of onset almost identical to those who had no sleep disorder at all. The lead author, Dr. Ricardo S. Osorio, a research professor of psychiatry at New York University, said the analysis, published online in Neurology, is an observational study that does not prove cause and effect. “But,” he added, “we need to increase the awareness that sleep disorders can increase the risk for cognitive impairment and possibly for Alzheimer’s. Whether treating sleep disorders truly slows the decline is still not known, but there is some evidence that it might.” © 2015 The New York Times Company
|By Cari Nierenberg and LiveScience Women who develop gestational diabetes early in their pregnancy have a higher chance of having a child with autism than women who don't develop the condition, a new study suggests. Researchers found that mothers-to-be who developed gestational diabetes — high blood sugar during pregnancy in women who have never had diabetes — by their 26th week of pregnancy were 63 percent more likely to have a child diagnosed with an autism spectrum disorder (ASD) compared with women who did not have gestational diabetes at any point during their pregnancy (and who also did not have type 2 diabetes prior to pregnancy). The finding does not mean that autism is common among children born to women who had gestational diabetes. "Autism is still rare," said study co-author Anny Xiang, a research scientist at Kaiser Permanente Southern California in Pasadena. The findings show that, although the risk of having a child with autism is still low among women who have gestational diabetes early in pregnancy (before 26 weeks), the study did find a relationship between these women and an increased risk that the child would have autism, Xiang said. The study, published today (April 14) in the Journal of the American Medical Association, looked at more than 320,000 children born in Southern California between 1995 and 2009. About 8 percent of the kids were born to mothers who had pregnancy-related diabetes, and 2 percent had mothers with type 2 diabetes. © 2015 Scientific American
By Neuroskeptic According to a large study just published in the Journal of Autism and Developmental Disorders, there’s no correlation between brain anatomy and self-reported autistic traits. Dutch researchers P. Cedric M. P. Koolschijn and colleagues looked at two samples of young Dutch adults: an ‘exploration’ sample of 204, and a separate ‘validation’ group of 304 individuals. Most of the participants did not have autism. The researchers looked for associations between various aspects of brain structure and autistic traits, using the AQ questionnaire, a popular self-report measure. Autistic traits are personality or behavior features similar to (but generally milder than) autism symptoms. For example, the first item on the AQ is “I prefer to do things with others rather than on my own.” If you disagree with that, you get a point. More points means more autistic traits. Koolschijn et al. used VBM, vertex-based cortical thickness analysis, and diffusion weighted imaging to explore different aspects of brain grey and white matter anatomy. However, although AQ scores were weakly correlated with the volume of a few brain areas in the exploration sample, none of these correlations were confirmed in the larger validation sample, suggesting that they were just false positives caused by the large number of multiple comparisons.
A study using mice has uncovered a possible cause of Alzheimer’s disease, and suggests that a drug currently being investigated in human clinical trials to treat cancer could prevent the illness. The research has been heralded as offering hope of finding new treatments for dementia, an illness that affects 850,000 people in the UK. The findings, by Duke University in America and published in the Journal of Neuroscience, are surprising, according to one of the authors, as they contradict current thinking on the disease. The research suggests that in mice with Alzheimer’s disease certain immune cells that normally protect the brain begin abnormally to consume an important nutrient called arginine. By blocking this process using the drug difluoromethylornithine (DFMO), memory loss and a buildup of sticky proteins known as brain plaques were prevented. The study used a type of mouse in which a number of important genes had been swapped to make the animal’s immune system more similar to a human’s. Senior author Carol Colton, professor of neurology at the Duke University School of Medicine, and a member of the Duke Institute for Brain Sciences, said: “If indeed arginine consumption is so important to the disease process, maybe we could block it and reverse the disease.” It was previously thought the brain releases molecules that ramp up the immune system, apparently damaging the brain, but the study found a heightened expression of genes associated with the suppression of the immune system. Author Matthew Kan said: “It’s surprising because [suppression of the immune system is] not what the field has been thinking is happening in AD [Alzheimer’s disease].” © 2015 Guardian News and Media Limited
Link ID: 20802 - Posted: 04.15.2015
Jon Hamilton There's new evidence that the brain's activity during sleep isn't random. And the findings could help explain why the brain consumes so much energy even when it appears to be resting. "There is something that's going on in a very structured manner during rest and during sleep," says Stanford neurologist Dr. Josef Parvizi, "and that will, of course, require energy consumption." For a long time, scientists dismissed the brain's electrical activity during rest and sleep as meaningless "noise." But then studies using fMRI began to reveal patterns suggesting coordinated activity. To take a closer look, Parvizi and a team of researchers studied three people awaiting surgery for epilepsy. These people spent several days with electrodes in their brains to help locate the source of their seizures. And that meant Parvizi's team was able to monitor the activity of small groups of brain cells in real time. "We wanted to know exactly what's going on during rest," Parvizi says, "and whether or not it reflects what went on during the daytime when the subject was not resting." In the study published online earlier this month in Neuron, the team first studied the volunteers while they were awake and answering simple questions like: Did you drive to work last week? "In order to answer yes or no, you retrieve a lot of facts; you retrieve a lot of visualized memories," Parvizi says. © 2015 NPR
By James Gallagher Health editor, BBC News website Those who were overweight had an 18% reduction in dementia, researchers found Being overweight cuts the risk of dementia, according to the largest and most precise investigation into the relationship. The researchers admit they were surprised by the findings, which run contrary to current health advice. The analysis of nearly two million British people, in the Lancet Diabetes & Endocrinology, showed underweight people had the highest risk. Dementia charities still advised not smoking, exercise and a balanced diet. Dementia is one of the most pressing modern health issues. The number of patients globally is expected to treble to 135 million by 2050. There is no cure or treatment, and the mainstay of advice has been to reduce risk by maintaining a healthy lifestyle. Yet it might be misguided. The team at Oxon Epidemiology and the London School of Hygiene and Tropical Medicine analysed medical records from 1,958,191 people aged 55, on average, for up to two decades. Their most conservative analysis showed underweight people had a 39% greater risk of dementia compared with being a healthy weight. But those who were overweight had an 18% reduction in dementia - and the figure was 24% for the obese. "Yes, it is a surprise," said lead researcher Dr Nawab Qizilbash. He told the BBC News website: "The controversial side is the observation that overweight and obese people have a lower risk of dementia than people with a normal, healthy body mass index. "That's contrary to most if not all studies that have been done, but if you collect them all together our study overwhelms them in terms of size and precision." Loss of tissue in a demented brain compared with a healthy one © 2015 BBC
By Ariana Eunjung Cha Autism has always been a tricky disorder to diagnose. There’s no such thing as a blood test, cheek swap or other accepted biological marker so specialists must depend on parent and teacher reports, observations and play assessments. Figuring out a child's trajectory once he or she is diagnosed is just as challenging. The spectrum is wide and some are destined to be on the mild end and be very talkative, sometimes almost indistinguishable from those without the disorder in some settings, while others will suffer from a more severe form and have trouble being able to speak basic words. Now scientists believe that they have a way to distinguish between those paths, at least in terms of language ability, in the toddler years using brain imaging. In an article published Thursday in the journal Neuron, scientists at the University of California-San Diego have found that children with autism spectrum disorder, or ASD, with good language outcomes have strikingly distinct patterns of brain activation as compared to those with poor language outcomes and typically developing toddlers. "Why some toddlers with ASD get better and develop good language and others do not has been a mystery that is of the utmost importance to solve," Eric Courchesne, one of the study’s authors and co-director of the University of California-San Diego's Autism Center, said in a statement. The images of the children in the study -- MRIs of the brain -- were taken at 12 to 29 months while their language was assessed one to two years later at 30 to 48 months.