Posts tagged psychology

ScienceDaily (Mar. 26, 2012) — Smoking alters the impact of a schizophrenia risk gene. Scientists from the universities of Zurich and Cologne demonstrate that healthy people who carry this risk gene and smoke process acoustic stimuli in a similarly deficient way as patients with schizophrenia. Furthermore, the impact is all the stronger the more the person smokes.

Schizophrenia has long been known to be hereditary. However, as a melting pot of disorders with different genetic causes is concealed behind manifestations of schizophrenia, research has still not been able to identify the main gene responsible to this day.

In order to study the genetic background of schizophrenia, the frequency of particular risk genes between healthy and ill people has mostly been compared until now. Pharmacopyschologist Professor Boris Quednow from University Hospital of Psychiatry, Zurich, and Professor Georg Winterer’s workgroup at the University of Cologne have now adopted a novel approach. Using electroencephalography (EEG), the scientists studied the processing of simple acoustic stimuli (a sequence of similar clicks). When processing a particular stimulus, healthy people suppress the processing of other stimuli that are irrelevant to the task at hand. Patients with schizophrenia exhibit deficits in this kind of stimulus filtering and thus their brains are probably inundated with too much information. As psychiatrically healthy people also filter stimuli with varying degrees of efficiency, individual stimulus processing can be associated with particular genes.

Smokers process stimuli less effectively

In a large-scale study involving over 1,800 healthy participants from the general population, Boris Quednow and Georg Winterer examined how far acoustic stimulus filtering is connected with a known risk gene for schizophrenia: the so-called “transcription factor 4” gene (TCF4). TCF4 is a protein that plays a key role in early brain development. As patients with schizophrenia often smoke, the scientists also studied the smoking habits of the test subjects.

The data collected shows that psychiatrically healthy carriers of the TCF4 gene also filter stimuli less effectively — like people who suffer from schizophrenia. It turned out that primarily smokers who carry the risk gene display a less effective filtering of acoustic impressions. This effect was all the more pronounced the more the people smoked. Non-smoking carriers of the risk gene, however, did not process stimuli much worse. “Smoking alters the impact of the TCF4 gene on acoustic stimulus filtering,” says Boris Quednow, explaining this kind of gene-environment interaction. “Therefore, smoking might also increase the impact of particular genes on the risk of schizophrenia.”

The results could also be significant for predicting schizophrenic disorders and for new treatment approaches, says Quednow and concludes: “Smoking should also be considered as an important cofactor for the risk of schizophrenia in future studies.” A combination of genetic (e.g. TCF4), electrophysiological (stimulus filtering) and demographic (smoking) factors could help diagnose the disorder more rapidly or also define new, genetically more uniform patient subgroups.

Source: Science Daily

ScienceDaily (Mar. 26, 2012) — Though autism is often not diagnosed until the age of three, some children begin to show signs of developmental delay before they turn a year old. While not all infants and toddlers with delays will develop autism spectrum disorders (ASD), experts point to early detection of these signs as key to capitalizing on early diagnosis and intervention, which is believed to improve developmental outcomes.

According to Dr. Rebecca Landa, director of the Center for Autism and Related Disorders at the Kennedy Krieger Institute in Baltimore, Md., parents need to be empowered to identify the warning signs of ASD and other communication delays.

"We want to encourage parents to become good observers of their children’s development so that they can see the earliest indicators of delays in a baby’s communication, social and motor skills," says Dr. Landa, who also cautions that some children who develop ASD don’t show signs until after the second birthday or regress after appearing to develop typically.

For the past decade, Dr. Landa has followed infant siblings of children with autism to identify red flags of the disorder in their earliest form. Her research has shown that diagnosis is possible in some children as young as 14 months and sparked the development of early intervention models that have been shown to improve outcomes for toddlers showing signs of ASD as young as one and two years old.

Dr. Landa recommends that as parents play with their infant (6 — 12 months), they look for the following signs that have been linked to later diagnosis of ASD or other communication disorders:

1. Rarely smiles when approached by caregivers 2. Rarely tries to imitate sounds and movements others make, such as smiling and laughing, during simple social exchanges 3. Delayed or infrequent babbling 4. Does not respond to his or her name with increasing consistency from 6 — 12 months 5. Does not gesture to communicate by 10 months 6. Poor eye contact 7. Seeks your attention infrequently 8. Repeatedly stiffens arms, hands, legs or displays unusual body movements such as rotating the hands on the wrists, uncommon postures or other repetitive behaviors 9. Does not reach up toward you when you reach to pick him or her up 10. Delays in motor development, including delayed rolling over, pushing up and crawling

"If parents suspect something is wrong with their child’s development, or that their child is losing skills, they should talk to their pediatrician or another developmental expert," says Dr. Landa. "Don’t adopt a ‘wait and see’ perspective. We want to identify delays early in development so that intervention can begin when children’s brains are more malleable and still developing their circuitry."

Source: Science Daily

March 26, 2012

A meta-analysis of previously published studies found that the ratio of blood plasma amyloid-β (Aβ) peptides Aβ42:Aβ40 was significantly associated with development of Alzheimer disease and dementia, according to a report published Online First by Archives of Neurology.

"Plasma levels of amyloid-β (Aβ) peptides have been a principal focus of the growing literature on blood-based biomarkers, but studies to date have varied in design, assay methods, and sample size, making it difficult to readily interpret the overall data," the authors write as background in the study.

Alain Koyama, S.M., then of Harvard School of Public Health and Brigham and Women’s Hospital, Boston, now with the University of California, San Francisco, and colleagues conducted a meta-analysis of 13 previously published studies to examine the association between plasma amyloid-β and development of dementia, Alzheimer disease (AD) and cognitive decline.

The 13 studies included in the analysis had a total of 10,303 participants, and were published between 1995 and 2011. The studies also included measurement of at least one relevant plasma amyloid-β species (Aβ40, Aβ42, or Aβ42: Aβ40 ratio) and reported an effect estimate for dementia, AD or cognitive decline.

The authors found that lower Aβ42: Aβ40 ratios were significantly associated with development of Alzheimer disease and dementia, with most studies in the analysis reporting similar findings. Plasma levels of Aβ40 and Aβ42 alone, however, were not significantly associated with either outcome.

"In conclusion, despite the limitations of existing research and heterogeneity across the studies considered, this systematic review and meta-analysis suggests that the ratio of plasma Aβ42: Aβ40 may have value in predicting the risk for later development of dementia or AD and merits further investigation."

More information: Arch Neurol. Published online March 26, 2012. doi:10.1001/archneurol.2011.1841

Provided by JAMA and Archives Journals

Source: medicalxpress.com

ScienceDaily (Mar. 26, 2012) — A new study, using brain imaging technology, reveals structural adaptations in short-track speed skaters’ brains which are likely to explain their extraordinary balance and co-ordination skills.

Short track speed skaters. (Credit: © sarah besson / Fotolia)

The work by Im Joo Rhyu from the Korea University College of Medicine, and colleagues, is published online in Springer’s journal Cerebellum.

The cerebellum in the brain plays an essential role in balance control, coordinated movement, and visually guided movement, which are key abilities required for short-track speed skaters as they glide on perfectly smooth ice, cornering and passing at high speeds. Previous studies have shown that damage to the cerebellum results in impaired balance and coordination. In addition, structural changes in the brain have been documented following training of complex motor skills, in both jugglers and basketball players for instance. Are these changes sports-specific?

To assess the effect of short-track speed skating training on the relative structure and size of the two brain hemispheres, the authors analyzed brain MRI scans of 16 male professional short-track speed skaters. They compared them to scans of 18 non-skaters, who did not engage in regular exercise.

They found that skaters had larger right hemispheres of the cerebellum and vermian lobules VI-VII (the lobes connecting the left and right parts of the cerebellum) than non-skaters. These results suggest that the specialized abilities of balance and coordination in skaters are associated with a certain amount of flexibility in the structure of the right hemisphere of the cerebellum and vermian VI-VII.

Why do the structural changes occur to the right side of the cerebellum? Gliding on smooth ice requires specialized abilities to control dynamic balance and coordination. During cornering at high speed, short-track speed skaters turn only to the left while maintaining balance on their right foot. Standing on the right foot activates the right lobes of the cerebellum.

In addition, learning a visually guided task is thought to occur in the right side of the brain. Therefore the larger volume of the right hemisphere of the cerebellum in these skaters is likely to be associated with the type of movements which the sport requires, for strong visual guidance while cornering and passing.

The authors conclude: “Short-track speed skaters’ specialized abilities of balance and coordination stimulate specific structural changes in the cerebellum, following extensive training. These changes reflect the effects of extraordinary abilities of balance and coordination on the right region of the brain.”

Source: Science Daily

March 26, 2012 by Bob Yirka

(Medical Xpress) — A research team made up of people from a wide variety of biological sciences has found that mice fed a diet high in fat tend to see an increase in the number of neurons created in the hypothalamus, a region of the brain associated with regulating energy use in the body. The team, as they describe in their paper published in Nature Neuroscience, write that the increase in neurons occurs in a part of the hypothalamus called the median eminence, which lies outside the blood-brain barrier.

Hypothalamic proliferative zone. For more details, Nature Neuroscience (2012) doi:10.1038/nn.3079

Suspecting that something unusual goes on with the hypothalamus and the median eminence in particular, when mice eat more fat, the research team put a group of mice on a diet very high in it. In the lab, mice are usually fed a diet that is approximately thirty five percent fat, which keeps them from gaining weight. In this study, the fat content was raised to sixty percent, which of course caused the mice to get fat. But, the team found, it also caused the creation of new brain cells in the median eminence to increase, from one to five percent.

Next the researchers forced the mouse brains to stop creating new brain cells while continuing to feed the mice the high fat diet. And surprisingly, the mice weight gain slowed and the mice demonstrated more energy. Adding to the good news was the fact that the median eminence lies outside of the blood-brain area (a separation of blood and brain fluid that prevents many materials in blood from reaching brain cells) meaning that the possibility of developing a therapy based on this research to help humans lose weight might be possible.

The researchers are quick to point out however, that there is no evidence yet that increased neuron production occurs in people who eat extra amounts of fat, or even in any other animal. They also say they don’t yet understand why new neuron growth occurs when mice are fed a high fat diet, but speculate that it may have something to do with detecting chemicals in the bloodstream and responding by sending signals to the rest of the hypothalamus.

More information: Tanycytes of the hypothalamic median eminence form a diet-responsive neurogenic niche, Nature Neuroscience (2012) doi:10.1038/nn.3079

Source: medicalxpress.com

March 26, 2012 By Angela Herring

All human languages contain two levels of structure, said Iris Berent, a psychology professor in Northeastern’s College of Science. One is syntax, or the ordering of words in a sentence. The other is phonology, or the sound structure of individual words.

Berent — whose research focuses on the phonological structure of language — examines the nature of linguistic competence, its origins and its interaction with reading. While previous studies have all centered on adult language acquisition, she is now working with infants to address two core questions.

“First,” she said, “do infants have the capacity to encode phonological rules? And, second, are some phonological rules innate?”

To address the first issue, Berent collaborated with neuroscientists Janet Werker, of the University of British Columbia, and Judit Gervain, of the Paris-based Centre National de la Recherche Scientifique.

By utilizing an optical brain imaging technique called near-infrared spectroscopy, or NIRS, the researchers found that newborns have the capacity to learn linguistic rules. This finding — published this month in the Journal of Cognitive Neuroscience — suggests that the neural foundations of language acquisition are present at birth.

Armed with this knowledge, Berent has begun conducting behavioral studies on more than two-dozen infants to explore whether linguistic rules are innate or entirely learned.

“We want to see whether infants prefer certain sound patterns to others even if neither occurs in their language,” Berent explained. “For instance, we know that human languages prefer sequences such as bnog over bdog. Would six-month-old infants show this preference even if their language (English) does not include either sequence?”

For the study, each child is placed in front of a video screen that displays an image pulsing in coordination with rotating sounds, such as “bnog” and “bdog.” Berent hypothesized that infants would look longer at the video screen when they hear sounds to which they are innately biased.

Preliminary results have upheld the hypothesis, but Berent is still accepting new subjects for the study. Her entire research program forms part of a new book called “The Phonological Mind,” which will be published by Cambridge University Press this year.

Provided by Northeastern University

Source: medicalxpress.com

March 26, 2012

(Medical Xpress) — Storytelling is a skill not everyone can master, but even the most crashing bore gets help from their audience’s brain which ‘talks over’ their monotonous quotes, according to scientists.

Researchers from the University of Glasgow’s Institute of Neuroscience and Psychology investigated the ‘voice-selective’ areas of the brain and revealed that when listening to someone monotonously repeating direct speech quotations, the brain will ‘talk over’ the speaker to make the quotes more vivid.

Previously, the researchers had shown the brain ‘talks’ when silently reading direct quotations.

Dr Bo Yao, the principal investigator of the study, said: “You may think the brain need not produce its own speech while listening to one that is already available.

“But, apparently, the brain is very picky on the speech it hears. When the brain hears monotonously-spoken direct speech quotations which it expects to be more vivid, the brain simply ‘talks over’ the speech it hears with more vivid speech utterances of its own.”

Dr Bo Yao explains why the brain ‘talks over’ boring speech: 

[Audio]

The research was conducted by Dr Yao and colleagues Professor Pascal Belin and Professor Christoph Scheepers within the Institute’s Centre for Cognitive Neuroimaging.

The team enlisted 18 participants in the study and scanned their brains using functional magnetic resonance imaging (fMRI) while they listened to audio clips of short stories containing direct or indirect speech quotations. The direct speech quotations — e.g., Mary said excitedly: “The latest Sherlock Holmes film is fantastic!” – were either spoken ‘vividly’ or ‘monotonously’ (i.e., with or without much variation in speech melody).

The results showed that listening to monotonously spoken direct speech quotations increased brain activity in the ‘voice-selective areas’ of the brain. These voice-selective areas – originally discovered by Prof Belin – are certain areas of the auditory cortex which are particularly interested in human voices when stimulated by actual speech sounds perceived by the ears.

However, the present and previous studies also reveal that these areas can be activated by different linguistic reporting styles – such as direct versus indirect speech.

Prof Scheepers said: “Direct speech quotations are generally assumed to be more vivid and perceptually engaging than indirect speech quotations as they are more frequently associated with depictions of voices, facial expressions and co-speech gestures.

“When the brain does not receive actual stimulation of auditory speech during silent reading, it tends to produce its own to enliven written direct speech quotations – a phenomenon commonly referred to as the ‘inner voice’ during silent reading. Now it appears the brain does the same even when listening to monotonously-spoken direct speech quotations.”

Dr Yao added: “This research demonstrates that human speech processing is an active process in which the brain generates models for the incoming speech utterances in order to predict actual auditory input.

“By doing so, the brain attempts to optimise the processing of the incoming speech, ensuring more speedy and accurate responses.

“These predictions are probably grounded in our past experiences in which direct speech is frequently associated with vivid depictions of the reported speaker’s voice whereas indirect speech is usually stated in a more flat and steady tone.

“The brain’s ‘talking over’ monotonously spoken direct quotes seems to reflect that it tries to bridge the incongruence between the expected speech utterances (vivid) and the actually perceived speech (monotonous) by simulating or imagining the expected vivid vocal depictions.

“We believe that such a simulation mechanism is an integral part of language comprehension — we naturally recruit our sensory and motor systems to interpret the language input. Language processing, in this sense, is embodied.”

The research paper ‘Brain “talks over” boring quotes: Top-down activation of voice-selective areas while listening to monotonous direct speech quotations’ is published in NeuroImage.

Provided by University of Glasgow

Source: medicalxpress.com 

March 24, 2012

(HealthDay) — Neurodegenerative diseases may be characterized by specific regions of the brain that are critical network epicenters, with disease-related vulnerability associated with shorter paths to the epicenter and greater total connectional flow, according to a study published in the March 22 issue of Neuron.

Neurodegenerative diseases may be characterized by specific regions of the brain that are critical network epicenters, with disease-related vulnerability associated with shorter paths to the epicenter and greater total connectional flow, according to a study published in the March 22 issue of Neuron.

To investigate how intrinsic connectivity in health predicts regional vulnerability to neurodegenerative disease, Juan Zhou, Ph.D., from the University of California in San Francisco, and colleagues used task-free functional magnetic resonance imaging to identify the healthy intrinsic connectivity patterns seeded by brain regions vulnerable to five neurodegenerative diseases (Alzheimer’s disease, behavioral variant frontotemporal dementia, semantic dementia, progressive nonfluent aphasia, and corticobasal syndrome).

The investigators found that, for each neurodegenerative disease, specific regions emerged as critical network epicenters, and their normal connectivity profile was most similar to the disease-linked pattern of atrophy. In healthy subjects, greater disease-related vulnerability was consistently associated with regions with shorter functional paths to the epicenters and also with higher total connectional flow.

"These findings best fit a transneuronal spread model of network-based vulnerability. Molecular pathological approaches may help clarify what makes each epicenter vulnerable to its targeting disease and how toxic protein species travel between networked brain structures," the authors write.

More information: Abstract

Source: medicalxpress.com

ScienceDaily (Mar. 24, 2012) — Researchers are suggesting that there is a link between the number of friends you have and the size of the region of the brain — known as the orbital prefrontal cortex — that is found just above the eyes. A new study shows that this brain region is bigger in people who have a larger number of friendships.

Friends. Researchers are suggesting that there is a link between the number of friends you have and the size of the region of the brain — known as the orbital prefrontal cortex — that is found just above the eyes. (Credit: © Rido / Fotolia)

Their study is published on 1 February 2012 in the journal, Proceedings of the Royal Society B.

The research was carried out as part of the British Academy Centenary ‘Lucy to Language’ project, led by Professor Robin Dunbar of the University of Oxford in a collaboration with Dr Joanne Powell and Dr Marta Garcia-Finana at Liverpool University, Dr Penny Lewis at Manchester University and Professor Neil Roberts at Edinburgh University.

The study suggests that we need to employ a set of cognitive skills to maintain a number of friends (and the keyword is ‘friends’ as opposed to just the total number of people we know). These skills are described by social scientists as ‘mentalising’ or ‘mind-reading’- a capacity to understand what another person is thinking, which is crucial to our ability to handle our complex social world, including the ability to hold conversations with one another. This study, for the first time, suggests that our competency in these skills is determined by the size of key regions of our brains (in particular, the frontal lobe).

Professor Dunbar, from the Institute of Cognitive and Evolutionary Anthropology, explained: ‘“Mentalising” is where one individual is able to follow a natural hierarchy involving other individuals’ mind states. For example, in the play ‘Othello’, Shakespeare manages to keep track of five separate mental states: he intended that his audience believes that Iago wants Othello to suppose that Desdemona loves Cassio [the italics signify the different mind states]. Being able to maintain five separate individuals’ mental states is the natural upper limit for most adults.’

The researchers took anatomical MR images of the brains of 40 volunteers at the Magnetic Resonance and Image Analysis Research Centre at the University of Liverpool to measure the size of the prefrontal cortex, the part of the brain used in high-level thinking. Participants were asked to make a list of everyone they had had social, as opposed to professional, contact with over the previous seven days. They also took a test to determine their competency in mentalising.

Professor Robin Dunbar, said: ‘We found that individuals who had more friends did better on mentalising tasks and had more neural volume in the orbital frontal cortex, the part of the forebrain immediately above the eyes. Understanding this link between an individual’s brain size and the number of friends they have helps us understand the mechanisms that have led to humans developing bigger brains than other primate species. The frontal lobes of the brain, in particular, have enlarged dramatically in humans over the last half million years.’

Dr Joanne Powell, from the Department of Psychology, University of Liverpool, said: ‘Perhaps the most important finding of our study is that we have been able to show that the relationship between brain size and social network size is mediated by mentalising skills. What this tells us is that the size of your brain determines your social skills, and it is these that allow you have many friends.’

Professor Dunbar said: ‘All the volunteers in this sample were postgraduate students of broadly similar ages with potentially similar opportunities for social activities. Of course, the amount of spare time for socialising, geography, personality and gender all influence friendship size, but we also know that at least some of these factors, notably gender, also correlate with mentalising skills. Our study finds there is a link between the ability to read how other people think and social network size.’

Professor Dunbar’s research was funded by the British Academy Centenary Research Project and by the British Academy Research Professorship. His research has already examined the different brain sizes of different species, but this study looks at the differences within species. Professor Dunbar published a paper last year, which found that people living near to the Poles needed larger brains for visual processing because of the dimmer light conditions.

Source: Science Daily

ScienceDaily (Mar. 23, 2012) — Nodding off in class may not be such a bad idea after all. New research from the University of Notre Dame shows that going to sleep shortly after learning new material is most beneficial for recall.

New research shows that going to sleep shortly after learning new material is most beneficial for recall. (Credit: © Claudia Nagel / Fotolia)

Notre Dame psychologist Jessica Payne and colleagues studied 207 students who habitually slept for at least six hours per night. Participants were randomly assigned to study declarative, semantically related or unrelated word pairs at 9 a.m. or 9 p.m., and returned for testing 30 minutes, 12 hours or 24 hours later. Declarative memory refers to the ability to consciously remember facts and events, and can be broken down into episodic memory (memory for events) and semantic memory (memory for facts about the world). People routinely use both types of memory every day — recalling where we parked today or learning how a colleague prefers to be addressed.

At the 12-hour retest, memory overall was superior following a night of sleep compared to a day of wakefulness. However, this performance difference was a result of a pronounced deterioration in memory for unrelated word pairs; there was no sleep-wake difference for related word pairs. At the 24-hour retest, with all subjects having received both a full night of sleep and a full day of wakefulness, subjects’ memories were superior when sleep occurred shortly after learning, rather than following a full day of wakefulness.

"Our study confirms that sleeping directly after learning something new is beneficial for memory. What’s novel about this study is that we tried to shine light on sleep’s influence on both types of declarative memory by studying semantically unrelated and related word pairs," Payne says.

"Since we found that sleeping soon after learning benefited both types of memory, this means that it would be a good thing to rehearse any information you need to remember just prior to going to bed. In some sense, you may be ‘telling’ the sleeping brain what to consolidate."

Source: Science Daily