Posts tagged psychology
Articles and news from the latest research reports.
Neuroscientists Determine How Treatment for Anxiety Disorders Silences Fear Neurons
Excessive fear can develop after a traumatic experience, leading to anxiety disorders such as post-traumatic stress disorder and phobias. During exposure therapy, an effective and common treatment for anxiety disorders, the patient confronts a fear or memory of a traumatic event in a safe environment, which leads to a gradual loss of fear. A new study in mice, published online today in Neuron, reports that exposure therapy remodels an inhibitory junction in the amygdala, a brain region important for fear in mice and humans. The findings improve our understanding of how exposure therapy suppresses fear responses and may aid in developing more effective treatments. The study, led by researchers at Tufts University School of Medicine and the Sackler School of Graduate Biomedical Sciences at Tufts, was partially funded by a New Innovator Award from the Office of the Director at the National Institutes of Health.
A fear-inducing situation activates a small group of neurons in the amygdala. Exposure therapy silences these fear neurons, causing them to be less active. As a result of this reduced activity, fear responses are alleviated. The research team sought to understand how exactly exposure therapy silences fear neurons.
The researchers found that exposure therapy not only silences fear neurons but also induces remodeling of a specific type of inhibitory junction, called the perisomatic synapse. Perisomatic inhibitory synapses are connections between neurons that enable one group of neurons to silence another group of neurons. Exposure therapy increases the number of perisomatic inhibitory synapses around fear neurons in the amygdala. This increase provides an explanation for how exposure therapy silences fear neurons.
“The increase in number of perisomatic inhibitory synapses is a form of remodeling in the brain. Interestingly, this form of remodeling does not seem to erase the memory of the fear-inducing event, but suppresses it,” said senior author, Leon Reijmers, Ph.D., assistant professor of neuroscience at Tufts University School of Medicine and member of the neuroscience program faculty at the Sackler School of Graduate Biomedical Sciences at Tufts.
Reijmers and his team discovered the increase in perisomatic inhibitory synapses by imaging neurons activated by fear in genetically manipulated mice. Connections in the human brain responsible for suppressing fear and storing fear memories are similar to those found in the mouse brain, making the mouse an appropriate model organism for studying fear circuits.
Mice were placed in a box and experienced a fear-inducing situation to create a fear response to the box. One group of mice, the control group, did not receive exposure therapy. Another group of mice, the comparison group, received exposure therapy to alleviate the fear response. For exposure therapy, the comparison group was repeatedly placed in the box without experiencing the fear-inducing situation, which led to a decreased fear response in these mice. This is also referred to as fear extinction.
The researchers found that mice subjected to exposure therapy had more perisomatic inhibitory synapses in the amygdala than mice who did not receive exposure therapy. Interestingly, this increase was found around fear neurons that became silent after exposure therapy.
“We showed that the remodeling of perisomatic inhibitory synapses is closely linked to the activity state of fear neurons. Our findings shed new light on the precise location where mechanisms of fear regulation might act. We hope that this will lead to new drug targets for improving exposure therapy,” said first author, Stéphanie Trouche, Ph.D., a former postdoctoral fellow in Reijmers’ lab at Tufts and now a medical research council investigator scientist at the University of Oxford in the United Kingdom.
“Exposure therapy in humans does not work for every patient, and in patients that do respond to the treatment, it rarely leads to a complete and permanent suppression of fear. For this reason, there is a need for treatments that can make exposure therapy more effective,” Reijmers added.
(Source: now.tufts.edu)
Exposure to Cortisol-Like Medications Before Birth May Contribute to Emotional Problems and Brain Changes
Neonatologists seem to perform miracles in the fight to support the survival of babies born prematurely.
To promote their survival, cortisol-like drugs called glucocorticoids are administered frequently to women in preterm labor to accelerate their babies’ lung maturation prior to birth. Cortisol is a substance naturally released by the body when stressed. But the levels of glucocorticoids administered to promote lung development are higher than that achieved with typical stress, perhaps only mirrored in the body’s reaction to extreme stresses.
The benefit of glucocorticoids is undisputed and has certainly saved the lives of countless babies, but this exposure also may have some negative consequences. Indeed, excessive glucocorticoid levels may have effects on brain development, perhaps contributing to emotional problems later in life.
In this issue of Biological Psychiatry, Dr. Elysia Davis at the University of Denver and her colleagues report new findings on the effects of synthetic glucocorticoid on human brain development. Their study focused on healthy children who were born full-term, avoiding the confounding effects of premature birth.
The investigators conducted brain imaging sessions in and carefully assessed 54 children, 6-10 years of age. The mothers of the participating children also completed reports on their child’s behavior. The researchers then divided the children into two groups: those who were exposed to glucocorticoids prenatally and those who were not.
In this study, children with fetal glucocorticoid exposure showed significant cortical thinning, and a thinner cortex also predicted more emotional problems. In one particularly affected part of the brain, the rostral anterior cingulate cortex, it was 8-9% thinner among children exposed to glucocorticoids. Interestingly, other studies have shown that this region of the brain is affected in individuals diagnosed with mood and anxiety disorders.
"Fetal exposure to a frequently administered stress hormone is associated with consequences for child brain development that persist for at least 6 to 10 years. These neurological changes are associated with increased risk for stress and emotional problems," Davis explained of their findings. "Importantly, these findings were observed among healthy children born full term."
Although such a finding does not indicate that glucocorticoids ‘caused’ these changes, the researchers did determine that the findings can’t be explained by any obvious confounding differences between the groups. The two groups did not differ on weight or gestational age at birth, apgar scores, maternal factors, or any other basic demographics. Thus, the findings do suggest that glucocorticoid administration may somehow alter the trajectory of brain development of exposed children.
"This study provides evidence that prenatal exposure to stress hormones shapes the construction of the fetal nervous system with consequences for the developing brain that persist into the preadolescent period," she added.
"This study highlights potential links between early cortisol exposure, cortical thinning and mood symptoms in children. It may provide important insights into the development of the brain and the long-term impact of maternal stress," commented Dr. John Krystal, Editor of Biological Psychiatry.
(Source: elsevier.com)
Babies can learn their first lullabies in the womb
An infant can recognise a lullaby heard in the womb for several months after birth, potentially supporting later speech development. This is indicated in a new study at the University of Helsinki.
The study focused on 24 women during the final trimester of their pregnancies. Half of the women played the melody of Twinkle Twinkle Little Star to their fetuses five days a week for the final stages of their pregnancies. The brains of the babies who heard the melody in utero reacted more strongly to the familiar melody both immediately and four months after birth when compared with the control group. These results show that fetuses can recognise and remember sounds from the outside world.
This is significant for the early rehabilitation, since rehabilitation aims at long-term changes in the brain.
“Even though our earlier research indicated that fetuses could learn minor details of speech, we did not know how long they could retain the information. These results show that babies are capable of learning at a very young age, and that the effects of the learning remain apparent in the brain for a long time,” expounds Eino Partanen, who is currently finishing his dissertation at the Cognitive Brain Research Unit.
“This is the first study to track how long fetal memories remain in the brain. The results are significant, as studying the responses in the brain let us focus on the foundations of fetal memory. The early mechanisms of memory are currently unknown,” points out Dr Minna Huotilainen, principal investigator.
The researchers believe that song and speech are most beneficial for the fetus in terms of speech development. According to the current understanding, the processing of singing and speech in the babies brains are partly based on shared mechanisms, and so hearing a song can support a baby’s speech development. However, little is known about the possible detrimental effects that noise in the workplace can cause to a fetus during the final trimester. An extensive research project on this topic is underway at the Finnish Institute of Occupational Health.
Baby brains are tuned to the specific actions of others
Imitation may be the sincerest form of flattery for adults, but for babies it’s their foremost tool for learning. As renowned people-watchers, babies often observe others demonstrate how to do things and then copy those body movements. It’s how little ones know, usually without explicit instructions, to hold a toy phone to the ear or guide a spoon to the mouth.
Now researchers from the University of Washington and Temple University have found the first evidence revealing a key aspect of the brain processing that occurs in babies to allow this learning by observation.
The findings, published online Oct. 30 by PLOS ONE, are the first to show that babies’ brains showed specific activation patterns when an adult performed a task with different parts of her body. When 14-month-old babies simply watched an adult use her hand to touch a toy, the hand area of the baby’s brain lit up. When another group of infants watched an adult touch the toy using only her foot, the foot area of the baby’s brain showed more activity.
"Babies are exquisitely careful people-watchers, and they’re primed to learn from others," said Andrew Meltzoff, co-author and co-director of the UW Institute for Learning & Brain Sciences. "And now we see that when babies watch someone else, it activates their own brains. This study is a first step in understanding the neuroscience of how babies learn through imitation."
The study took advantage of how the brain is organized. The sensory and motor area of the cortex, the outer portion of the brain known for its creased appearance, is arranged by body part with each area of the body represented in identifiable neural real estate. Prick your finger, stick out your tongue, or kick a ball and distinct areas of the brain light up according to a somatotopic map.
Other studies show that adults show this somatotopic brain activation while watching someone else use different body parts, suggesting that adults understand the actions of others in relation to their own bodies. The researchers wondered whether the same would be true in babies.
The 70 infants in the study wore electroencephalogram, or EEG, caps with embedded sensors that detected brain activity in the regions of the cortex that respond to movement or touch of the feet and hands. Sitting on a parent’s lap, each baby watched as an experimenter touched a toy placed on a low table between the baby and the experimenter.
The toy had a clear plastic dome and was mounted on a sturdy base. When the experimenter pressed the dome with her hand or foot, music played and confetti in the dome spun. The experimenter repeated the action – taking breaks after every four presses – until the baby lost interest.
"Our findings show that when babies see others produce actions with a particular body part, their brains are activated in a corresponding way," said Joni Saby, lead author and a psychology graduate student at Temple University in Philadelphia. "This mapping may facilitate imitation and could play a role in the baby’s ability to then produce the same actions themselves."
One of the basics for babies to learn is how to copy what they see adults do. In other words, they must first know that it is indeed their hand and not their foot, mouth or other body part that is needed.
The new study shows that babies’ brains are organized in a somatotopic way that helps crack the interpersonal code. The connection between doing and seeing actions maps hand to hand, foot to foot, all before they can name those body parts through language.
"The reason this is exciting is that it gives insight into a crucial aspect of imitation," said co-author Peter Marshall, an associate psychology professor at Temple University. "To imitate the action of another person, babies first need to register what body part the other person used. Our findings suggest that babies do this in a particular way by mapping the actions of the other person onto their own body."
Meltzoff added, “The neural system of babies directly connects them to other people, which jump-starts imitation and social-emotional connectedness and bonding. Babies look at you and see themselves.”
Research Finds Pain In Infancy Alters Response To Stress, Anxiety Later In Life
Early life pain alters neural circuits in the brain that regulate stress, suggesting pain experienced by infants who often do not receive analgesics while undergoing tests and treatment in neonatal intensive care may permanently alter future responses to anxiety, stress and pain in adulthood, a research team led by Dr. Anne Murphy, associate director of the Neuroscience Institute at Georgia State University, has discovered.
An estimated 12 percent of live births in the U.S. are considered premature, researchers said. These infants often spend an average of 25 days in neonatal intensive care, where they endure 10-to-18 painful and inflammatory procedures each day, including insertion of feeding tubes and intravenous lines, intubation and repeated heel lance. Despite evidence that pain and stress circuitry in the brain are established and functional in preterm infants, about 65 percent of these procedures are performed without benefit of analgesia. Some clinical studies suggest early life pain has an immediate and long-term impact on responses to stress- and anxiety-provoking events.
The Georgia State study examined whether a single painful inflammatory procedure performed on male and female rat pups on the day of birth alters specific brain receptors that affect behavioral sensitivity to stress, anxiety and pain in adulthood. The findings demonstrated that such an experience is associated with site-specific changes in the brain that regulate how the pups responded to stressful situations. Alterations in how these receptors function have also been associated with mood disorders.
The study findings mirror what is now being reported clinically. Children who experienced unresolved pain following birth show reduced responsiveness to pain and stress.
“While a dampened response to painful and stressful situations may seem advantageous at first, the ability to respond appropriately to a potentially harmful stimulus is necessary in the long term,” Dr. Murphy said.
“The fact that less than 35 percent of infants undergoing painful and invasive procedures receive any sort of pre- or post-operative pain relief needs to be re-evaluated in order to reduce physical and mental health complications associated with preterm birth.”
Find a space with total darkness and slowly move your hand from side to side in front of your face. What do you see?
If the answer is a shadowy shape moving past, you are probably not imagining things. With the help of computerized eye trackers, a new cognitive science study finds that at least 50 percent of people can see the movement of their own hand even in the absence of all light.
"Seeing in total darkness? According to the current understanding of natural vision, that just doesn’t happen," says Duje Tadin, a professor of brain and cognitive sciences at the University of Rochester who led the investigation. "But this research shows that our own movements transmit sensory signals that also can create real visual perceptions in the brain, even in the complete absence of optical input."
Through five separate experiments involving 129 individuals, the authors found that this eerie ability to see our hand in the dark suggests that our brain combines information from different senses to create our perceptions. The ability also “underscores that what we normally perceive of as sight is really as much a function of our brains as our eyes,” says first author Kevin Dieter, a post-doctoral fellow in psychology at Vanderbilt University.
The study seems to confirm anecdotal reports that spelunkers in lightless caves often are able to see their hands. In other words, the “spelunker illusion,” as one blogger dubbed it, is likely not an illusion after all.
For most people, this ability to see self-motion in darkness probably is learned, the authors conclude. “We get such reliable exposure to the sight of our own hand moving that our brains learn to predict the expected moving image even without actual visual input,” says Dieter.
Tadin, Dieter, and their team from the University of Rochester and Vanderbilt University reported their findings online October 30 in Psychological Science, the flagship journal of the Association for Psychological Science.
Although seeing one’s hand move in the dark may seem simple, the experimental challenge in this study was to measure objectively a perception that is, at its core, subjective. That hurdle at first stumped Tadin and his postdoctoral advisor at Vanderbilt Randolph Blake after they initially stumbled upon the puzzling observation in 2005. “While the phenomenon looked real to us, how could we determine if other people were really seeing their own moving hand rather than just telling us what they thought we wanted to hear?” asks Blake, the Centennial Professor of Psychology at Vanderbilt and a co-author on the paper.
Years later, Dieter, at the time a doctoral student working in Tadin’s Rochester lab, helped devise several experiments to probe the sight-without-light mystery. For starters, the researchers set up false expectations. In one scenario, they led subjects to expect to see “motion under low lighting conditions” with blindfolds that appeared to have tiny holes in them. In a second set up, the same participants had similar blindfolds without the “holes” and were led to believe they would see nothing. In both set ups, the blindfolds were, in fact, equally effective at blocking out all light. A third experiment consisted of the experimenter waving his hand in front of the blindfolded subject. Ultimately, participants were fitted with a computerized eye tracker in total darkness to confirm whether self-reported perceptions of movement lined up with objective measures.
In addition to testing typical subjects, the team also recruited people who experience a blending of their senses in daily life. Known as synesthetes, these individuals may, for example, see colors when they hear music or even taste sounds. This study focused on grapheme-color synesthetes, individuals who always see numbers or letters in specific colors.
The researchers enlisted individuals from Rochester, Nashville, Fenton, Michigan, and Seoul, South Korea, but, in a lucky coincidence, one synesthete could not have been closer. At the time, Lindsay Bronnenkant was working as a lab technician for co-author David Knill, a professor of brain and cognitive sciences at Rochester.
"As a child, I just assumed that everybody associated colors with letters," says the 2010 Rochester graduate who majored in brain and cognitive sciences. For Bronnenkant, "A is always yellow, but Y is an oranger yellow." B is navy, C burnt orange, and so on. She thought of these associations as normal, "like when you smell apple pie and you think of grandma." She doesn’t remember a time when she did not see numbers and letters in color, but she does wonder if the particular colors she associates with numbers derived from the billiard balls her family had going up. When she donned the blindfold and waved her hand in the experiment, "what I saw was a blur. It was very dim, but it was almost like I was looking at a light source."
Bronnenkant was not atypical in that respect. Across all types of participants, about half detected the motion of their own hand and they did so consistently, despite the expectations created with the faux holes. And very few subjects saw motion when the experimenter waved his hand, underscoring the importance of self-motion in this visual experience. As measured by the eye tracker, subjects who reported seeing motion were also able to smoothly track the motion of their hand in darkness more accurately than those who reported no visual sensation—46 percent versus 20 percent of the time.
Reports of the strength of visual images varied widely among participants, but synesthetes were strikingly better at not just seeing movement, but also experiencing clear visual form. As an extreme example in the eye tracking experiment, one synesthete exhibited near perfect smooth eye movement—95 percent accuracy—as she followed her hand in darkness. In other words, she could track her hand in total darkness as well as if the lights were on.
"You can’t just imagine a target and get smooth eye movement," explains Knill. "If there is no moving target, your eye movements will be noticeably jerky."
The link with synesthesia suggests that our human ability to see self-motion is based on neural connections between the senses, says Knill. “We know that sensory cross talk underlies synesthesia. But seeing color with numbers is probably just the tip of the iceberg; synesthesia may involve many areas of atypical brain processing.”
Does that mean that most humans are preprogrammed to see themselves in the dark? Not likely, says Tadin. “Innate or experience? I’m pretty sure it’s experience,” he concludes. “Our brains are remarkably good at finding such reliable patterns. The brain is there to pick up patterns—visual, auditory, thinking, movement. And this is one association that is so highly repeatable that it is logical our brains picked up on it and exploited it.”
Whether hardwired or learned, Bronnenkant finds the cross talk between her senses a potent reminder of the underlying interconnectivity of nature. “It’s almost a spiritual thing,” she says. “Sometimes, yeah, I think to myself, ‘I just got this sense from a billiard ball,’ but other times I think that being able to cross modalities actually reflects how unified the world is. We think of math and chemistry and art as different fields, but really they are facets of the same world; they are just ways of looking at the world through different lenses.”
Scientists reduce behaviours associated with problem gambling in rats
With the help of a rat casino, University of British Columbia brain researchers have successfully reduced behaviours in rats that are commonly associated with compulsive gambling in humans.
The study, which featured the first successful modeling of slot machine-style gambling with rats in North America, is the first to show that problem gambling behaviours can be treated with drugs that block dopamine D4 receptors. The findings have been published in Biological Psychiatry journal.
“More work is needed, but these findings offer new hope for the treatment of gambling addiction, which is a growing public health concern,” says Paul Cocker, lead author of the study and a PhD student in UBC’s Dept. of Psychology. “This study sheds important new light on the brain processes involved with gambling and gambling addictions.”
For the study, rats gambled for sugar pellets using a slot machine-style device that featured three flashing lights and two levers they could push with their paws. The rats exhibited several behaviours associated with problem gambling such as the tendency to treat “near misses” similar to wins.
Building on previous research, the team focused on the dopamine D4 receptor, which has been linked to a variety of behavioural disorders, but never proven useful in treatment. The study found that rats treated with a dopamine D4 receptor-blocking medication exhibited reduced levels of behaviours associated with problem gambling.
While findings suggest that blocking the D4 dopamine receptor may help to reduce pathological gambling behaviours in humans, the researchers note that further research is needed before the drugs can be considered a viable pharmaceutical treatment for pathological gambling in humans.
BACKGROUND
“Pathological gambling is increasingly seen as a behavioural addiction similar to drug or alcohol addiction, but we know comparatively little about how to treat problem gambling,” says Cocker. “Our study is the first to show that by blocking these receptors we might be able to reduce the rewarding aspects of near-misses that appear to be important in gambling.”
Methods: In the 16-month study,a cohort of 32 laboratory rats responded to a series of three flashing lights before choosing between two levers. One combination of lights (all lights illuminated) signaled a win and seven combinations (zero, one or two lights) signaled a loss. A “cash-out” lever rewarded the rat with 10 sugar pellets on winning trials, but gave a 10-second “time out” penalty on losing trails. The “roll again” lever allowed the rats to begin a new trial without penalty, but provided no sugar pellets.
Interestingly, the rats showed a tendency towards choosing the cash-out lever when two lights (near-miss) illuminated, suggesting that rats, like people, are susceptible to the near-miss effect. By blocking the D4 receptors with drugs, the researchers were successfully able to reduce the rat’s choice of the “cash-out” lever on non-winning trials.
The D4 blocker drug used in the study has previously been tested on humans in attempts to treat behaviour disorders like schizophrenia but appeared to have no effect.
Near misses: This common cognitive bias is considered an important factor in the development of pathological gambling problems. The fact that slot machines tend to have a relatively high proportion of near-misses in comparison to other gambling games may be the reason that slot machines are such a particularly addictive form of gambling.
Study authors: Paul Cocker and Prof.Catharine Winstanley (UBC Dept. of Psychology), Bernard Le Foll (University of Toronto, Centre for Addiction and Mental Health) and Robert D. Rogers (Bangor University). The study, A Selective Role for Dopamine D4 Receptors in Modulating Reward Expectancy in a Rodent Slot Machine Task, is available upon request.
UBC’s Laboratory of Molecular and Behavioural Neuroscience, led by Psychology Prof. Catharine Winstanley, focuses on understanding the biological mechanisms of functions such as impulse control and gambling, leading to new and improved treatments for disorders like attention deficit hyperactivity disorder, bipolar disorder, personality disorders, and drug addiction.
Problem gambling: Compulsive gambling affects between three and five percent of North Americans, according to recent statistics.
Poor motor performance linked to poor academic skills in the first school years
Children with poor motor performance at the school entry were found to have poorer reading and arithmetic skills than their better performing peers during the first three years of school. However, no relationship was found between cardiovascular fitness and academic skills, according to a new study published in Medicine & Science in Sports & Exercise.
The study investigated the relationships of cardiovascular fitness and motor performance in the first grade to reading and arithmetic skills in grades 1–3 among 174 Finnish children as part of The Physical Activity and Nutrition (PANIC) Study at the University of Eastern Finland and The First Steps Study at the University of Jyväskylä. Children who performed poorly in agility, speed and manual dexterity tests and had poor overall motor performance in the first grade had lower reading and arithmetic test scores in grades 1–3 than children with better performance in motor tests. Especially children in the lowest motor performance third had poorer reading and arithmetic test scores than children in the other thirds. These associations were stronger in boys than girls. Unexpectedly, however, cardiovascular fitness was not related to academic skills.
The findings of the study highlight the importance of motor performance and movement skills over cardiovascular fitness for children’s school success during the first years of school. The academic development of children with poor motor performance should be carefully monitored and appropriate actions to support the development of reading, arithmetic and movement skills should be started when needed.
Nurturing may protect kids from brain changes linked to poverty
Growing up in poverty can have long-lasting, negative consequences for a child. But for poor children raised by parents who lack nurturing skills, the effects may be particularly worrisome, according to a new study at Washington University School of Medicine in St. Louis.
Among children living in poverty, the researchers identified changes in the brain that can lead to lifelong problems like depression, learning difficulties and limitations in the ability to cope with stress. The study showed that the extent of those changes was influenced strongly by whether parents were nurturing.
The good news, according to the researchers, is that a nurturing home life may offset some of the negative changes in brain anatomy among poor children. And the findings suggest that teaching nurturing skills to parents — particularly those living in poverty — may provide a lifetime benefit for their children.
The study is published online Oct. 28 and will appear in the November issue of JAMA Pediatrics.
Using magnetic resonance imaging (MRI), the researchers found that poor children with parents who were not very nurturing were likely to have less gray and white matter in the brain. Gray matter is closely linked to intelligence, while white matter often is linked to the brain’s ability to transmit signals between various cells and structures.
The MRI scans also revealed that two key brain structures were smaller in children who were living in poverty: the amygdala, a key structure in emotional health, and the hippocampus, an area of the brain that is critical to learning and memory.
“We’ve known for many years from behavioral studies that exposure to poverty is one of the most powerful predictors of poor developmental outcomes for children,” said principal investigator Joan L. Luby, MD, a Washington University child psychiatrist at St. Louis Children’s Hospital. “A growing number of neuroscience and brain-imaging studies recently have shown that poverty also has a negative effect on brain development.
“What’s new is that our research shows the effects of poverty on the developing brain, particularly in the hippocampus, are strongly influenced by parenting and life stresses that the children experience.”
Luby, a professor of psychiatry and director of the university’s Early Emotional Development Program, is in the midst of a long-term study of childhood depression. As part of the Preschool Depression Study, she has been following 305 healthy and depressed kids since they were in preschool. As the children have grown, they also have received MRI scans that track brain development.
“We actually stumbled upon this finding,” she said. “Initially, we thought we would have to control for the effects of poverty, but as we attempted to control for it, we realized that poverty was really driving some of the outcomes of interest, and that caused us to change our focus to poverty, which was not the initial aim of this study.”
In the new study, Luby’s team looked at scans from 145 children enrolled in the depression study. Some were depressed, others healthy, and others had been diagnosed with different psychiatric disorders such as ADHD (attention-deficit hyperactivity disorder). As she studied these children, Luby said it became clear that poverty and stressful life events, which often go hand in hand, were affecting brain development.
The researchers measured poverty using what’s called an income-to-needs ratio, which takes a family’s size and annual income into account. The current federal poverty level is $23,550 for a family of four.
Although the investigators found that poverty had a powerful impact on gray matter, white matter, hippocampal and amygdala volumes, they found that the main driver of changes among poor children in the volume of the hippocampus was not lack of money but the extent to which poor parents nurture their children. The hippocampus is a key brain region of interest in studying the risk for impairments.
Luby’s team rated nurturing using observations made by the researchers — who were unaware of characteristics such as income level or whether a child had a psychiatric diagnosis — when the children came to the clinic for an appointment. And on one of the clinic visits, the researchers rated parental nurturing using a test of the child’s impatience and of a parent’s patience with that child.
While waiting to see a health professional, a child was given a gift-wrapped package, and that child’s parent or caregiver was given paperwork to fill out. The child, meanwhile, was told that s/he could not open the package until the caregiver completed the paperwork, a task that researchers estimated would take about 10 minutes.
Luby’s team found that parents living in poverty appeared more stressed and less able to nurture their children during that exercise. In cases where poor parents were rated as good nurturers, the children were less likely to exhibit the same anatomical changes in the brain as poor children with less nurturing parents.
“Parents can be less emotionally responsive for a whole host of reasons,” Luby said. “They may work two jobs or regularly find themselves trying to scrounge together money for food. Perhaps they live in an unsafe environment. They may be facing many stresses, and some don’t have the capacity to invest in supportive parenting as much as parents who don’t have to live in the midst of those adverse circumstances.”
The researchers also found that poorer children were more likely to experience stressful life events, which can influence brain development. Anything from moving to a new house to changing schools to having parents who fight regularly to the death of a loved one is considered a stressful life event.
Luby believes this study could provide policymakers with at least a partial answer to the question of what it is about poverty that can be so detrimental to a child’s long-term developmental outcome. Because it appears that a nurturing parent or caregiver may prevent some of the changes in brain anatomy that this study identified, Luby said it is vital that society invest in public health prevention programs that target parental nurturing skills. She suggested that a key next step would be to determine if there are sensitive developmental periods when interventions with parents might have the most powerful impact.
“Children who experience positive caregiver support don’t necessarily experience the developmental, cognitive and emotional problems that can affect children who don’t receive as much nurturing, and that is tremendously important,” Luby said. “This study gives us a feasible, tangible target with the suggestion that early interventions that focus on parenting may provide a tremendous payoff.”
New study shows promise for first effective medicine to treat cocaine dependence
New research published in JAMA Psychiatry reveals that topiramate, a drug approved by the U.S. Food and Drug Administration (FDA) to treat epilepsy and migraine headaches, also could be the first reliable medication to help treat cocaine dependence.
The study, led by Bankole A. Johnson, DSc. MD., MB.ChB., MPhil., chairman of the Department of Psychiatry at the University of Maryland School of Medicine and head of the School’s new Brain Science Research Consortium Unit, with support from the National Institutes of Health and Agency for Healthcare Research and Quality, is one of the first to establish a pharmacological treatment for cocaine addiction, for which there are currently no FDA-approved medications.
Addiction affects 13.2 to 19.7 million cocaine users worldwide. Cocaine is responsible for more U.S. emergency room visits than any other illegal drug. Cocaine harms the brain, heart, blood vessels, and lungs — and can even cause sudden death.
Professor Johnson, one of the nation’s leading neuroscientists and psychopharmacologists, had previously found that topiramate was a safe and effective treatment for alcohol dependence compared with placebo.
In releasing the new study, Professor Johnson, who conducted the research when he was with Department of Psychiatry and Neurobehavioral Sciences at the University of Virginia, provided full disclosures, which follow the text of this news announcement.*
The study enrolled 142 participants, aged 18 years or older, seeking treatment for cocaine dependence. Following enrollment, participants were randomly assigned into a topiramate group or placebo group. Neither the participants nor the healthcare professionals administering the treatment knew who was in which group (double-blinded study).
Using an intent-to-treat analysis, the researchers found that topiramate was more efficacious than placebo at increasing the participants’ weekly proportion of cocaine nonuse days and in increasing the likelihood that participants would have cocaine-free weeks. Furthermore, compared with placebo, topiramate also was significantly associated with a decrease in craving for cocaine and an improvement in participants’ global functioning.
The study investigators also observed few side effects due to drug treatment. In general, participants in the topiramate group experienced mild side-effects, including abnormal tingling skin sensations, taste distortions, anorexia, and difficulty concentrating.
"Our findings reveal that topiramate is a safe and robustly efficacious medicine for the treatment of cocaine dependence, and has the potential to make a major contribution to the global health crisis of addiction," Professor Johnson said. "However, topiramate treatment also is associated with glaucoma, and higher doses of the drug can increase the risk of side effects; therefore, caution must be exercised when prescribing the drug, especially when given in high doses."
These results build upon earlier work from Professor. Johnson’s group which indicated that individuals dependent on cocaine, but not seeking treatment, who took topiramate were more likely to experience reduced cravings and preference for cocaine, compared with placebo. The findings of the current study indicate that topiramate may be even more effective in treating people with addiction who actively want to quit using cocaine.
"Because topiramate is the first medication to demonstrate a robust therapeutic effect for the treatment of cocaine or alcohol dependence, its fundamental neurochemical effects provide important clues as to common links in the neurobiological basis of the addictive process in general," remarked Professor Johnson. "These findings also add to our understanding of how addiction affects the brain because it demonstrates the unique concept that dual neurotransmitter modulation, by simultaneously augmenting the inhibitory action of gamma amino butyric acid and inhibiting the excitatory effects of glutamate, can result in therapeutic effects that reduce the propensity to use cocaine."
*Editor’s Notes:
A. Statement of Disclosure
Professor Johnson reported serving as a consultant for Johnson & Johnson (Ortho-McNeil Janssen Scientific Affairs, LLC) the manufacturer of topiramate, from 2003-2008 and currently has no affiliation with that Company, Transcept Pharmaceuticals, Inc. from 2006-2008, Eli Lilly and Company from 2009-2010, and Organon from 2007-2010. He currently consults for D&A Pharma, ADial Pharmaceuticals, LLC, (with which he also serves as chairman), and Psychological Education Publishing Company (PEPCo), LLC. Topiramate is currently available as a generic medicine in the USA, and Professor Johnson has no commercial affiliation with any generic manufacturer of topiramate. Dr. Liu reported serving as a consultant for Celladon Corporation. No other disclosures were reported.
B. Funding/ Support
This study was supported by NIH grants 501 DAO17296-04 and 5 RC1AA019274-02, and Agency for Healthcare Research and Quality grant 7 RO1 HS020263092.