Posts tagged psychology
Articles and news from the latest research reports.
Inside the Letterbox: How Literacy Transforms the Human Brain
Although I find the diversity of the world’s writing systems bewildering, there is also a striking regularity that remains hidden. Whenever we read—whether our language is Japanese, Hebrew, English, or Italian—each of us relies on very similar brain networks. In particular, a small region of the visual cortex becomes active with remarkable reproducibility in the brains of all readers. A brief localizer scan, during which images of brain activity are collected as a person responds to written words, faces, objects, and other visual stimuli, serves to identify this region. Written words never fail to activate a small region at the base of the left hemisphere, always at the same place, give or take a few millimeters.
Experts call this region the visual word form area, but in a recent book for the general public, I dubbed it the brain’s letterbox, because it concentrates much of our visual knowledge of letters and their configurations. Indeed, this site is amazingly specialized. The letterbox responds to written words more than it does to most other categories of visual stimuli, including pictures of faces, objects, houses, and even Arabic numerals.Its efficiency is so great that it even responds to words that we fail to recognize consciously—words made subliminal by flashing them for a fraction of a second. Yet it performs highly sophisticated operations that are indispensable to fluent reading. For instance, the letterbox is the first visual area that recognizes that “READ” and “read” depict the same word by representing strings of letters invariantly for changes in case, which is no small feat if you consider that uppercase and lowercase letters such as “A” and “a” bear very little similarity. Furthermore, if it is impaired or disconnected via brain surgery or a cerebral infarct (type of stroke), the patient may develop a syndrome called pure alexia. He or she will be unable to recognize even a single word, as well as faces, objects, digits, and Arabic numerals. Yet many of these patients can still speak and understand spoken language fluently, and they may even still write; only their visual capacity to process letter strings seems dramatically affected.
The brain of any educated adult contains a circuit specialized for reading. But how is this possible, given that reading is an extremely recent and highly variable cultural activity? The alphabet is only about 4,000 years old, and until recently, only a very small fraction of humanity could read. Thus, there was no time for Darwinian evolution to shape our genome and adapt our brain networks to the particularities of reading. How is it, then, that we all possess a specialized letterbox area?
People can sense a smile before it appears on the face
But a forced or polite smile does not transmit the same signals, meaning we only detect it when it is visible, reports journal Psychological Science.
Researchers say the study reflects the unique social value of a heartfelt smile, which involves specific movements of muscles around the eyes.
A team from Bangor University had noted that pairs of strangers getting to know one another not only exchanged smiles, they almost always matched the particular smile type, whether genuine or polite.
But they responded much more quickly to their partners’ genuine smiles than their polite smiles, suggesting that they were anticipating the genuine smiles.
In the lab, the results were repeated and data from electrical sensors on participants’ faces revealed that they engaged smile-related muscles when they expected a genuine smile to appear but showed no such activity when expecting polite smiles.
The different responses suggest that genuine smiles are more valuable social rewards, said Dr Erin Heerey.
She said: “These findings give us the first clear suggestion that the basic processes that guide responses to reward also play a role in guiding social behaviour on a moment-to-moment basis during interactions.
"No two interactions are alike, yet people still manage to smoothly coordinate their speech and nonverbal behaviors with those of another person."
She said that polite smiles typically occur when sociocultural norms dictate that smiling is appropriate.
Genuine smiles, on the other hand, signify pleasure, occur spontaneously, and are indicated by engagement of specific muscles around the eye.
She said the study could help those who find social interactions tricky.
She explained: “As we progress in our understanding of how social interactions unfold, these findings may help to guide the development of interventions for people who find social interactions difficult, such as those with social anxiety, autism, or schizophrenia.”
From the mouths of babes – The truth about toddler talk
The sound of small children chattering has always been considered cute – but not particularly sophisticated. However, research by a Newcastle University expert has shown their speech is far more advanced than previously understood.
Dr Cristina Dye, a lecturer in child language development, found that two to three- year-olds are using grammar far sooner than expected.
She studied fifty French speaking youngsters aged between 23 and 37 months, capturing tens of thousands of their utterances.
Dr Dye, who carried out the research while at Cornell University in the United States, found that the children were using ‘little words’ which form the skeleton of sentences such as a, an, can, is, an, far sooner than previously thought.
Dr Dye and her team used advanced recording technology including highly sensitive microphones placed close to the children, to capture the precise sounds the children voiced. They spent years painstakingly analysing every minute sound made by the toddlers and the context in which it was produced.
They found a clear, yet previously undetected, pattern of sounds and puffs of air, which consistently replaced grammatical words in many of the children’s utterances.
Dr Dye said: “Many of the toddlers we studied made a small sound, a soft breath, or a pause, at exactly the place that a grammatical word would normally be uttered.”
“The fact that this sound was always produced in the correct place in the sentence leads us to believe that young children are knowledgeable of grammatical words. They are far more sophisticated in their grammatical competence than we ever understood.
“Despite the fact the toddlers we studied were acquiring French, our findings are expected to extend to other languages. I believe we should give toddlers more credit – they’re much more amazing than we realised.”
For decades the prevailing view among developmental specialists has been that children’s early word combinations are devoid of grammatical words. On this view, children then undergo a ‘tadpole to frog’ transformation where due to an unknown mechanism, they start to develop grammar in their speech. Dye’s results now challenge the old view.
Dr Dye said: “The research sheds light on a really important part of a child’s development. Language is one of the things that makes us human and understanding how we acquire it shows just how amazing children are.
“There are also implications for understanding language delay in children. When children don’t learn to speak normally it can lead to serious issues later in life. For example, those who have it are more likely to suffer from mental illness or be unemployed later in life. If we can understand what is ‘normal’ as early as possible then we can intervene sooner to help those children.”
The research was originally published in the Journal of Linguistics.
(Source: ncl.ac.uk)
Stress Test and Brain Scans Pinpoint Two Distinct Forms of Gulf War Illness
Researchers at Georgetown University Medical Center say their new work suggests that Gulf War illness may have two distinct forms depending on which brain regions have atrophied. Their study of Gulf War veterans, published online today in PLOS ONE, may help explain why clinicians have consistently encountered veterans with different symptoms and complaints.
Using brain imaging that was acquired before and after exercise tests, the researchers studied the effects of physical stress on the veterans and controls. Following exercise, subgroups were evident. In 18 veterans, they found that pain levels increased after completion of the exercise stress tests exercised; fMRI scans in these participants showed loss of brain matter in adjacent regions associated with pain regulation.
During cognitive tasks, this group showed an increased use of the basal ganglia — a potential compensatory strategy the brain uses that is also seen in neurodegenerative disorders such as Alzheimer’s disease. Following exercise, this group lost the ability to employ their basal ganglia, suggesting an adverse response to a physiological stressor.
In addition, “a separate group of 10 veterans had a very different clinical alteration,” says lead author Rakib Rayhan, a researcher in the lab of the study’s senior investigator, James Baraniuk, MD, a professor of medicine at GUMC.
In these 10 veterans, the researchers found substantial increases in heart rate. They also discovered that this subgroup had atrophy in the brain stem, which regulates heart rate. .
In addition, brain scans during a cognitive task performed prior to exercise showed increased compensatory use of the cerebellum, again a trait seen in neurodegenerative disorders. Like the other group, this cohort lost the ability to use this compensatory area after exercise.
Alterations in cognition, brain structure and exercise-induced symptoms found in the veterans were absent in the 10-participant matched control group, the researchers say.
“The use of other brain areas to compensate for a damaged area is seen in other disorders, such as Alzheimer’s disease, which is why we believe our data show that these veterans are suffering from central nervous system dysfunction,” Rayhan explains. He adds, however, that because such changes are similar to other neurodegenerative states, it doesn’t mean that veterans will progress to Alzheimer’s or other diseases.
These findings — a surprise to researchers — follow a study in Gulf War veterans published in March in PLOS ONE that reported abnormalities in the bundle of nerve fibers connecting the brain areas involved in the processing and perception of pain and fatigue.
Gulf War Illness is the mysterious malady believed to have affected more than 200,000 military personnel who served in the 1990-1991 Operation Desert Shield and Desert Storm.
Although veterans were exposed to nerve agents, pesticides and herbicides (among other toxic chemicals), no one has definitively linked any single exposure or underlying mechanism to Gulf War illness.
The symptoms of Gulf War illness — which have not been widely accepted by the public or medical professionals — range from mild to debilitating and can include widespread pain, fatigue and headache, as well as cognitive and gastrointestinal dysfunctions.
“Our findings help explain and validate what these veterans have long said about their illness,” Rayhan says.
Sleep Mechanism Identified That Plays Role in Emotional Memory
Sleep researchers from University of California campuses in Riverside and San Diego have identified the sleep mechanism that enables the brain to consolidate emotional memory and found that a popular prescription sleep aid heightens the recollection of and response to negative memories.
Their findings have implications for individuals suffering from insomnia related to posttraumatic stress disorder (PTSD) and other anxiety disorders who are prescribed zolpidem (Ambien) to help them sleep.
The study — “Pharmacologically Increasing Sleep Spindles Enhances Recognition for Negative and High-arousal Memories” — appears in the Journal of Cognitive Neuroscience. It was funded by a National Institutes of Health career award to Sara C. Mednick, assistant professor of psychology at UC Riverside, of $651,999 over five years.
Mednick and UC San Diego psychologists Erik J. Kaestner and John T. Wixted determined that a sleep feature known as sleep spindles — bursts of brain activity that last for a second or less during a specific stage of sleep — are important for emotional memory.
Research Mednick published earlier this year demonstrated the critical role that sleep spindles play in consolidating information from short-term to long-term memory in the hippocampus, located in the cerebral cortex of the brain. Zolpidem enhanced the process, a discovery that could lead to new sleep therapies to improve memory for aging adults and those with dementia, Alzheimer’s and schizophrenia. It was the first study to show that sleep can be manipulated with pharmacology to improve memory.
“We know that sleep spindles are involved in declarative memory — explicit information we recall about the world, such as places, people and events, ” she explained.
But until now, researchers had not considered sleep spindles as playing a role in emotional memory , focusing instead on rapid eye movement (REM) sleep.
Using two commonly prescribed sleep aids — zolpidem and sodium oxybate (Xyrem) — Mednick, Kaestner and Wixted were able to tease apart the effects of sleep spindles and rapid eye movement (REM) sleep on the recall of emotional memories. They determined that sleep spindles, not REM, affect emotional memory.
The researchers gave zolpidem, sodium oxybate (Xyrem) and a placebo to 28 men and women between the ages of 18 and 39 who were normal sleepers, allowing several days between doses to allow the pharmaceuticals to leave their bodies. The participants viewed standardized images known to elicit positive and negative responses for one second before and after taking supervised naps. They recalled more images that had negative or highly arousing content after taking zolpidem, a finding that also suggests that the brain may favor consolidation of negative memories, she said.
“I was surprised by the specificity of the results, that the emotional memory improvement was specifically for the negative and high-arousal memories, and the ramifications of these results for people with anxiety disorders and PTSD,” Mednick said. “These are people who already have heightened memory for negative and high-arousal memories. Sleep drugs might be improving their memories for things they don’t want to remember.”
The study may have even broader implications, the researchers said. Clinical guidelines of the U.S. Department of Veterans Affairs and Department of Defense recommend against the routine use of benzodiazepines to treat PTSD, although their use increased among men and women with PTSD between 2003 and 2010. The effects of benzodiazepines on sleep are similar to those of zolpidem.
The U.S. Air Force uses zolpidem as one of the prescribed “no-go pills” to help flight crews calm down after taking stimulants to stay awake during long missions, the researchers noted in the study.
“In light of the present results, it would be worthwhile to investigate whether the administration of benzodiazepine-like drugs may be increasing the retention of highly arousing and negative memories, which would have a countertherapeutic effect,” they wrote. “Further research on the relationship between hypnotics and emotional mood disorders would seem to be in order.”
(Source: ucrtoday.ucr.edu)
In a National Institutes of Health (NIH) funded clinical trial, researchers at Emory have discovered that specific patterns of brain activity may indicate whether a depressed patient will or will not respond to treatment with medication or psychotherapy. The study was published June 12, 2013, in JAMA Psychiatry Online First.
The choice of medication versus psychotherapy is often based on the preference of the patient or clinician, rather than objective factors. On average, only 35-40 percent of patients get well with whatever treatment they start with.
"To be ill with depression any longer than necessary can be perilous," says Helen Mayberg,md principal investigator for the study and professor of psychiatry, neurology and radiology at Emory University School of Medicine. "This is a serious illness and the prolonged suffering resulting from an ineffective treatment can have serious medical, personal and social consequences. Our goal is not just to get patients well, but to get them well as fast as possible, using the treatment that is best for each individual."
Mayberg’s positron emission tomography (PET) studies over the years have given clues about what may be going on in the brain when people are depressed, and how different treatments affect brain activity.
These studies have also suggested that scan patterns prior to treatment might provide important clues as to which treatment to choose. In this study, the investigators used PET scans to measure brain glucose metabolism, an important index of brain functioning to test this hypothesis.
Participants in the trial were randomly assigned to receive a 12-week course of either the SSRI medication escitalopram or cognitive behavior therapy (CBT) after first undergoing a pretreatment PET scan.
The team found that activity in one particular region of the brain, the anterior insula, could discriminate patients who recovered from those who were non-responders to the treatment assigned. Specifically, patients with low activity in the insula showed remission with CBT, but poor response to medication; patients with high activity in the insula did well with medication, and poorly with CBT.
"These data suggest that if you treat based on a patient’s brain type, you increase the chance of getting them into remission," says Mayberg.
Mayberg is quick to add that this approach needs to be replicated before it would be appropriate for routine treatment selection decisions for individual depressed patients. It is, however, a first step to better define different types of depression that can be used to select a specific treatment for a patient.
A treatment stratification approach is done routinely in the management of other medical conditions such as infections, cancer, and heart disease, notes Mayberg. “The study reported here provides important first results towards the development of brain-based treatment algorithms that match a patient to the treatment with the highest likelihood of success, while also avoiding those treatments that will be ineffective.”
A rather complex complex: Brain scans reveal internal conflict during Jung’s word association test
Over 100 years ago psychologist Carl Gustav Jung penned his theory of ‘complexes’ where he explained how unconscious psychological issues can be triggered by people, events, or Jung believed, through word association tests.
New research in the Journal of Analytical Psychology is the first to reveal how modern brain function technology allows us to see inside the mind as a ‘hot button’ word triggers a state of internal conflict between the left and right parts of the brain.
The study revealed that some words trigger a subconscious internal conflict between our sense of selves and downloaded brain programs referring to “other” beings.
Analysis showed how this conflict takes place between the left and the right brain over three seconds, after which the left brain takes over to ensure ‘hot buttons’ will continue to be active.
"We found that when a complex is activated, brain circuits involved in how we sense ourselves, but also other people, get activated," said Dr. Leon Petchkovsky. "However, as there is no external person, the ‘other’ circuits really refer to internalized programs about how an ‘other’ person might respond. When a hot button gets pressed, ‘internal self’ and ‘internal other’ get into an argument."
"If we can manage to stay with the conflict rather than pseudo-resolve it prematurely, it may be possible to move beyond it," said Petchkovsky. "We can do this in psychotherapy, or by developing ‘mindfulness’ meditation skills. This makes for fewer ‘hot-buttons’ and a happier life."
Further research into this technology may help to develop an office-based test for condtions such as schizophrenia. Jung noticed that when schizophrenic patients responded to the word association test, their complexes tended to predominate for a much longer time and they would often get a burst of auditory hallucinations when they hit complexed responses.
In Dr Petchkovsky’s research with two schizophrenic patients found that their right brain activity persists for much longer than other patients and they reported an increase in auditory hallucination activity when complexes are struck.
(Source: eurekalert.org)
Do Antidepressants Impair the Ability to Extinguish Fear?
An interesting new report of animal research published in Biological Psychiatry suggests that common antidepressant medications may impair a form of learning that is important clinically.
(Photo: ALAMY)
Selective serotonin reuptake inhibitors, commonly called SSRIs, are a class of antidepressant widely used to treat depression, as well as a range of anxiety disorders, but the effects of these drugs on learning and memory are poorly understood.
In a previous study, Nesha Burghardt, then a graduate student at New York University, and her colleagues demonstrated that long-term SSRI treatment impairs fear conditioning in rats. As a follow-up, they have now tested the effects of antidepressant treatment on extinction learning in rats using auditory fear conditioning, a model of fear learning that involves the amygdala. The amygdala is a region of the brain vitally important for processing memory and emotion.
They found that long-term, but not short-term, SSRI treatment impairs extinction learning, which is the ability to learn that a conditioned stimulus no longer predicts an aversive event.
"This impairment may have important consequences clinically, since extinction-based exposure therapy is often used to treat anxiety disorders and antidepressants are often administered simultaneously," said Dr. Burghardt. "Based on our work, medication-induced impairments in extinction learning may actually disrupt the beneficial effects of exposure-therapy."
This finding is consistent with the results of several clinical studies showing that combined treatment can impede the benefits of exposure therapy or even natural resilience to the impact of traumatic stress at long-term follow-up.
The authors also suggest a mechanism for this effect on fear learning. They reported that the antidepressants decreased the levels of one of the subunits of the NMDA receptor (NR2B) in the amygdala. The NMDA receptor is critically involved in fear-related learning, so these reductions are believed to contribute to the observed effects.
Dr. John Krystal, Editor of Biological Psychiatry, commented, “We know that antidepressants play important roles in the treatment of depression and anxiety disorders. However, it is important to understand the limitations of these medications so that we can improve the effectiveness of the treatment for these disorders.”
(Source: elsevier.com)
Reduced brain volume in kids with low birth-weight tied to academic struggles
An analysis of recent data from magnetic resonance imaging (MRI) of 97 adolescents who were part of study begun with very low birth weight babies born in 1982-1986 in a Cleveland neonatal intensive care unit has tied smaller brain volumes to poor academic achievement.
More than half of the babies that weighed less than 1.66 pounds and more than 30 percent of those less than 3.31 pounds at birth later had academic deficits. (Less than 1.66 pounds is considered extremely low birth weight; less than 3.31 pounds is labeled very low birth weight.) Lower birth weight was associated to smaller brain volumes in some of these children, and smaller brain volume, in turn, was tied to academic deficits.
Researchers also found that 65.6 percent of very low birth weight and 41.2 percent of extremely preterm children had experienced academic achievement similar to normal weight peers.
The research team — led by Caron A.C. Clark, a scientist in the Department of Psychology and Child and Family Center at the University of Oregon — detected an overall reduced volume of mid-brain structures, the caudate and corpus callosum, which are involved in connectivity, executive attention and motor control.
The findings, based a logistic regression analyses of the MRIs done approximately five years ago, were published in the May issue of the journal Neuropsychology. The longitudinal study originally was launched in the 1980s with a grant from the National Institute of Child Health and Human Development (National Institutes of Health, grant HD 26554) to H. Gerry Taylor of Case Western University, who was the senior author and principal investigator on the new paper.
"Our new study shows that pre-term births do not necessarily mean academic difficulties are ahead," Clark said. "We had this group of children that did have academic difficulties, but there were a lot of kids in this data set who didn’t and, in fact, displayed the same trajectories as their normal birth-weight peers."
Academic progress of the 201 original participants had been assessed early in their school years, again four years later and then annually until they were almost 17 years old. “We had the opportunity to explore this very rich data set,” Clark said. “There are very few studies that follow this population of children over time, where their trajectories of growth at school are tracked. We were interested in seeing how development unfolds over time.”
The findings, Clark added, provide new insights but also raise questions such as why some low-birth-weight babies develop normally and others do not? “It is very difficult to pick up which kids will need the most intensive interventions really early, which we know can be really important.”
The findings also provide a snapshot of children of very low birth weights who were born in NICU 30 years ago. Since then, technologies and care have improved, she said, meaning that underweight babies born prematurely today might have an advantage over those followed in the study. However, she added, improving NICUs also are allowing yet smaller babies to survive.
Clark now is exploring these findings for early warning clues that might help drive informed interventions. “Pre-term birth does mean that you are much more likely to experience brain abnormalities that seem to put you at risk for these outcomes,” she said. “They seem to be a pretty strong predictor of poor cognitive development as children age. We really need to find ways to prevent these brain abnormalities and subsequent academic difficulties in these kids who are born so small.”
China’s Alzheimer’s time bomb revealed
In 2010, China had more people living with Alzheimer’s disease than any other country in the world – and twice as many cases of Alzheimer’s and other kinds of dementia as the World Health Organization thought.
Cases of all kinds of age-related dementia in the country rose from 3.7 million in 1990 to 9.2 million in 2010. This is the finding of the first comprehensive analysis of Chinese epidemiological research, made possible by the recent digitisation of Chinese-language research papers. Previous estimates, based on English-language papers, seem to have under-reported the number of cases by half.
"We are now only beginning to comprehend the enormous value in this ‘parallel universe’ of information," says Igor Rutan of the University of Edinburgh, UK, who was part of the team that carried out the research.
The figures are bad news for a country where 90 per cent of the elderly must be cared for by their families – old people who still have family members living are not allowed to be admitted to a nursing home – even as widespread migration to cities has disrupted the traditional family structure.
Population bulge
The findings are a reflection of China’s ageing population, and its policies.
As countries modernise, death rates fall, and later on birth rates fall as more people take up birth control. Between the two events, though, there is a “bulge” of births, the source of the modern world’s population explosion. Eventually birth and death rates roughly equalise, but the birth bulge remains as an age bulge in the population.
This reached an extreme in China, where a surge in births in the 1950s and 1960s was followed by plummeting birth rates in the 1970s, later reinforced by China’s one-child policy. “Family planning policy means China is becoming an ageing country much faster than other middle-income countries such as India,” says co-author Wei Wang of Edith Cowan University in Perth, Australia.
In its youth, the bulge underpinned China’s economic development. But by 2033, it is predicted that working-age people will be outnumbered by dependents, mostly the elderly.
The new research shows that they will need more care than China was expecting. Dementia rises in an ageing population: cases increased from 4.9 to 6.3 million in the greying European Union between 2004 and 2010.
Unhealthy lifestyle
"The rates in China are similar or even higher than rates in Europe and the US," says Wang.
And they are rising. In 1990, the team estimates, 1.8 per cent of Chinese aged 65 to 69, and 42.1 per cent aged 95 to 99, had dementia. In 2010 those figures were 2.6 and 60.5 per cent, respectively. If similar rates hold in other middle-income countries, there might be 20 per cent more cases of Alzheimer’s worldwide – five million more – than now estimated, the authors calculate.
The increase in China might reflect better diagnosis, but an urbanising lifestyle could also be causing more dementia. “Obesity, diabetes and suboptimal health contribute,” says Wang.
Martin Prince of King’s College London, who is organising another survey for dementia in China, says that if midlife obesity is a risk factor for dementia, then future rates in China could be 20 per cent higher than estimated.
(Source: newscientist.com)