Posts tagged psychology
Articles and news from the latest research reports.
Study shows anaesthesia may harm memory
General anaesthesia before the age of one may impair memory later in childhood, and the effects may possibly be lifelong, a study said Monday.
This was the conclusion of scientists who compared the recollection skills of two groups of children — some who had undergone anaesthesia in infancy and others who had not.
The children, aged six to 11 and divided into two groups of 28 each, were tested over a period of 10 months for their ability to recollect specific drawings and details therein.
The children who had been anaesthetised as babies had about 28 per cent less recollection on average than their peers, and scored 20 per cent lower in tests that assessed how much detail they could remember about the drawings.
"The children did not differ in tests measuring intelligence or behaviour, but those who had received anaesthesia had significantly lower recollection scores," said a media summary provided by the journal Neuropsychopharmacology, which published the results.
Does ‘free will’ stem from brain noise?
Our ability to make choices — and sometimes mistakes — might arise from random fluctuations in the brain’s background electrical noise, according to a recent study from the Center for Mind and Brain at the University of California, Davis.
"How do we behave independently of cause and effect?" said Jesse Bengson, a postdoctoral researcher at the center and first author on the paper. "This shows how arbitrary states in the brain can influence apparently voluntary decisions."
The brain has a normal level of “background noise,” Bengson said, as electrical activity patterns fluctuate across the brain. In the new study, decisions could be predicted based on the pattern of brain activity immediately before a decision was made.
Bengson sat volunteers in front of a screen and told them to fix their attention on the center, while using electroencephalography, or EEG, to record their brains’ electrical activity. The volunteers were instructed to make a decision to look either to the left or to the right when a cue symbol appeared on screen, and then to report their decision.
The cue to look left or right appeared at random intervals, so the volunteers could not consciously or unconsciously prepare for it.
The brain has a normal level of “background noise,” Bengson said, as electrical activity patterns fluctuate across the brain. The researchers found that the pattern of activity in the second or so before the cue symbol appeared — before the volunteers could know they were going to make a decision — could predict the likely outcome of the decision.
"The state of the brain right before presentation of the cue determines whether you will attend to the left or to the right," Bengson said.
The experiment builds on a famous 1970s experiment by Benjamin Libet, a psychologist at UCSF who was later affiliated with the UC Davis Center for Neuroscience.
Libet also measured brain electrical activity immediately before a volunteer made a decision to press a switch in response to a visual signal. He found brain activity immediately before the volunteer reported deciding to press the switch.
The new results build on Libet’s finding, because they provide a model for how brain activity could precede decision, Bengson said. Additionally, Libet had to rely on when volunteers said they made their decision. In the new experiment, the random timing means that “we know people aren’t making the decision in advance,” Bengson said.
Libet’s experiment raised questions of free will — if our brain is preparing to act before we know we are going to act, how do we make a conscious decision to act? The new work, though, shows how “brain noise” might actually create the opening for free will, Bengson said.
"It inserts a random effect that allows us to be freed from simple cause and effect," he said.
The work, which was funded by the National Institutes of Health, was published online in the Journal of Cognitive Neuroscience.
Rats show regret, a cognitive behavior once thought to be uniquely human
New research from the Department of Neuroscience at the University of Minnesota reveals that rats show regret, a cognitive behavior once thought to be uniquely and fundamentally human.
Research findings were recently published in Nature Neuroscience.
To measure the cognitive behavior of regret, A. David Redish, Ph.D., a professor of neuroscience in the University of Minnesota Department of Neuroscience, and Adam Steiner, a graduate student in the Graduate Program in Neuroscience, who led the study, started from the definitions of regret that economists and psychologists have identified in the past.
"Regret is the recognition that you made a mistake, that if you had done something else, you would have been better off," said Redish. "The difficult part of this study was separating regret from disappointment, which is when things aren’t as good as you would have hoped. The key to distinguishing between the two was letting the rats choose what to do."
Redish and Steiner developed a new task that asked rats how long they were willing to wait for certain foods. “It’s like waiting in line at a restaurant,” said Redish. “If the line is too long at the Chinese food restaurant, then you give up and go to the Indian food restaurant across the street.”
In this task, which they named “Restaurant Row,” the rat is presented with a series of food options but has limited time at each “restaurant.”
Research findings show rats were willing to wait longer for certain flavors, implying they had individual preferences. Because they could measure the rats’ individual preferences, Steiner and Redish could measure good deals and bad deals. Sometimes, the rats skipped a good deal and found themselves facing a bad deal.
"In humans, a part of the brain called the orbitofrontal cortex is active during regret. We found in rats that recognized they had made a mistake, indicators in the orbitofrontal cortex represented the missed opportunity. Interestingly, the rat’s orbitofrontal cortex represented what the rat should have done, not the missed reward. This makes sense because you don’t regret the thing you didn’t get, you regret the thing you didn’t do," said Redish.
Redish adds that results from Restaurant Row allow neuroscientists to ask additional questions to better understand why humans do things the way they do. By building upon this animal model of regret, Redish believes future research could help us understand how regret affects the decisions we make.
How do people lose their native language?
Sgt Bowe Bergdahl spoke English for 23 years until he was captured by Taliban fighters in Afghanistan five years ago. But since his release, he has trouble speaking it, says his father. How can you lose your native language, asks Taylor Kate Brown.
Losing the left side of the world: Rightward shift in human spatial attention with sleep onset
Unilateral brain damage can lead to a striking deficit in awareness of stimuli on one side of space called Spatial Neglect. Patient studies show that neglect of the left is markedly more persistent than of the right and that its severity increases under states of low alertness. There have been suggestions that this alertness-spatial awareness link may be detectable in the general population. Here, healthy human volunteers performed an auditory spatial localisation task whilst transitioning in and out of sleep. We show, using independent electroencephalographic measures, that normal drowsiness is linked with a remarkable unidirectional tendency to mislocate left-sided stimuli to the right. The effect may form a useful healthy model of neglect and help in understanding why leftward inattention is disproportionately persistent after brain injury. The results also cast light on marked changes in conscious experience before full sleep onset.
(Image: ALAMY)
Study shows increasing rates of premature death and violent crime in people with schizophrenia since 1970s
New research, published in The Lancet Psychiatry journal, shows that rates of adverse outcomes, including premature death and violent crime, in people with schizophrenia are increasing, compared to the general population.
The results come from a unique study, led by Dr Seena Fazel, at Oxford University, UK, which analyses long-term adverse outcomes – including conviction for a violent crime (such as homicide or bodily harm) premature death (before the age of 56), and death by suicide – between 1972 and 2009 in nearly 25,000 people in Sweden diagnosed with schizophrenia or related disorders.
For the first time, the researchers compared adverse outcomes in people with a diagnosis of schizophrenia to both the general population and to unaffected siblings, allowing them to account for risk factors within families (such as parental criminality or violence) which might be expected to affect the risk of suicide or violent behaviour in siblings.
Overall, the results show that within five years of diagnosis, around 1 in 50 men and women with schizophrenia (2.3% of men and 1.7% of women) died by suicide; around one in 10 (10.7%) of men and around one in 37 (2.7%) of women with schizophrenia were convicted of a violent offence within five years of diagnosis. Overall, men and women with schizophrenia were eight times more likely to die prematurely than the general population.
Analysing the changing rate of adverse outcomes across the study period (1972 – 2009), the researchers found that the risk of premature death, suicide, and conviction for a violent offence has increased for men and women with schizophrenia in the last 38 years, compared with both the general population, and their unaffected siblings.
By tracking the number of nights spent in hospital by people with schizophrenia during the study period, the study shows that these increased rates of adverse outcomes appear to be associated with decreasing levels of inpatient care for these patients, although the study does not provide any evidence for a causal connection between decreasing inpatient care and adverse outcomes.
The researchers also analysed risk factors for adverse outcomes in both people with schizophrenia, the general population, and unaffected siblings. Across all three groups, the risk factors for violence and premature death were broadly similar, and included drug use disorders, criminality, and self-harm, all before diagnosis – suggesting that improved strategies to address these risk factors have the potential to reduce violence and premature deaths across the population, and not just in those with schizophrenia.
According to Dr Fazel, “In recent years, there has been a lot of focus on primary prevention of schizophrenia – preventing people from getting ill. While primary prevention is clearly essential and may be some decades away, our study highlights the crucial importance of secondary prevention – treating and managing the risks of adverse outcomes, such as self-harm or violent behaviour, in patients. Risks of these adverse outcomes relative to others in society appear to be increasing in recent decades, suggesting that there is still much work to be done in developing new treatments and mitigating risks of adverse outcomes in people with schizophrenia.”*
Dr Eric Elbogen and Sally Johnson, at the University of North Carolina-Chapel Hill School of Medicine, USA, write in a linked Comment that, “One of the unique aspects of this study—that violence and suicide were analysed simultaneously—has an important implication for how we as a society perceive people with mental illness. News coverage of schizophrenia and other psychiatric disorders often focuses on violence and crime. Much less attention is paid to suicide and self-harm in people with severe mental illnesses.”
However, they add that, “Importantly, we should remember that, when reporting about the intricate links between schizophrenia and these adverse outcomes, most people with schizophrenia and related disorders are neither violent nor suicidal. Despite the need to ensure people with schizophrenia are provided help to reduce their risks of suicide, violence, or premature death, researchers reporting findings also bear the burden of ensuring that most people with schizophrenia and related disorders, who are not violent, are not left to contend with stigma and discrimination. Policy makers, researchers, and clinicians need to remember the importance of appropriately weighing up the issue of schizophrenia relative to the myriad of other factors that contribute to increased risk of violence and suicide.”
(Source: alphagalileo.org)
Brain signals link physical fitness to better language skills in children
Children who are physically fit have faster and more robust neuro-electrical brain responses during reading than their less-fit peers, researchers report.
These differences correspond with better language skills in the children who are more fit, and occur whether they’re reading straightforward sentences or sentences that contain errors of grammar or syntax.
The new findings, reported in the journal Brain and Cognition, do not prove that higher fitness directly influences the changes seen in the electrical activity of the brain, the researchers say, but offer a potential mechanism to explain why fitness correlates so closely with better cognitive performance on a variety of tasks.
“All we know is there is something different about higher and lower fit kids,” said University of Illinois kinesiology and community health professor Charles Hillman who led the research with graduate student Mark Scudder and psychology professor Kara Federmeier. “Now whether that difference is caused by fitness or maybe some third variable that (affects) both fitness and language processing, we don’t know yet.”
The researchers used electroencephalography (EEG), placing an electrode cap on the scalp to capture some of the electrical impulses associated with brain activity. The squiggly readouts from the electrodes look like seismic readings captured during an earthquake, and characteristic wave patterns are associated with different tasks.
These patterns are called “event-related potentials” (ERPs), and vary according to the person being evaluated and the nature of the stimulus, Scudder said.
For example, if you hear or read a word in a sentence that makes sense (“You wear shoes on your feet”), the component of the brain waveform known as the N400 is less pronounced than if you read a sentence in which the word no longer makes sense (“At school we sing shoes and dance,” for example), Scudder said.
“We focused on the N400 because it is associated with the processing of the meaning of a word,” he said. “And then we also looked at another ERP, the P600, which is associated with the grammatical rules of a sentence.” Federmeier, a study co-author, is an expert in the neurobiological basis of language. Her work inspired the new analysis.
The researchers found that children who were more fit (as measured by oxygen uptake during exercise) had higher amplitude N400 and P600 waves than their less-fit peers when reading normal or nonsensical sentences. The N400 also had shorter latency in children who were more fit, suggesting that they processed the same information more quickly than their peers.
Most importantly, the researchers said, these differences in brain activity corresponded to better reading performance and language comprehension in the children who were more fit.
“Previous reports have shown that greater N400 amplitude is seen in higher-ability readers,” Scudder said.
“Our study shows that the brain function of higher fit kids is different, in the sense that they appear to be able to better allocate resources in the brain towards aspects of cognition that support reading comprehension,” Hillman said.
More work must be done to tease out the causes of improved cognition in kids who are more fit, Hillman said, but the new findings add to a growing body of research that finds strong links between fitness and healthy brain function.
Many studies conducted in the last decade, on children and older adults, ”have repeatedly demonstrated an effect of increases in either physical activity in one’s lifestyle or improvements in aerobic fitness, and the implications of those health behaviors for brain structure, brain function and cognitive performance,” Hillman said.
Children with autism have elevated levels of steroid hormones in the womb
Children who later develop autism are exposed to elevated levels of steroid hormones (for example testosterone, progesterone and cortisol) in the womb, according to scientists from the University of Cambridge and the Statens Serum Institute in Copenhagen, Denmark. The finding may help explain why autism is more common in males than females. However, the researchers caution it should not be used to screen for the condition.
The team of researchers, led by Professor Simon Baron-Cohen and Dr Michael Lombardo in Cambridge and Professor Bent Nørgaard-Pedersen in Denmark, utilized approximately 19,500 amniotic fluid samples stored in a Danish biobank from individuals born between 1993-1999. Amniotic fluid surrounds the baby in the womb during pregnancy and is collected when some women choose to have an amniocentesis around 15-16 weeks of pregnancy. This coincides with a critical period for early brain development and sexual differentiation, and thus allows scientists access into this important window in fetal development. The researchers identified amniotic fluid samples from 128 males later diagnosed with an autism spectrum condition and matched these up with information from a central register of all psychiatric diagnoses in Denmark.
Within the amniotic fluid the researchers looked at four key ‘sex steroid’ hormones that are each synthesized, step-by-step from the preceding one*. They also tested the steroid hormone cortisol that lies outside this pathway. The researchers found that levels of all steroid hormones were highly associated with each other and most importantly, that the autism group on average had higher levels of all steroid hormones, compared to a typically developing male comparison group. The results of the study, which was funded by the Medical Research Council, are published today in the journal Molecular Psychiatry.
Professor Baron-Cohen said: “This is one of the earliest non-genetic biomarkers that has been identified in children who go on to develop autism. We previously knew that elevated prenatal testosterone is associated with slower social and language development, better attention to detail, and more autistic traits. Now, for the first time, we have also shown that these steroid hormones are elevated in children clinically diagnosed with autism. Because some of these hormones are produced in much higher quantities in males than in females, this may help us explain why autism is more common in males.”
He added: “These new results are particularly striking because they are found across all the subgroups on the autism spectrum, for the first time uniting those with Asperger Syndrome, classic autism, or Pervasive Developmental Disorder Not-Otherwise-Specified. We now want to test if the same finding is found in females with autism.”
Dr Michael Lombardo said: “This result potentially has very important implications about the early biological mechanisms that alter brain development in autism and also pinpoints an important window in fetal development when such mechanisms exert their effects.”
Steroid hormones are particularly important because they exert influence on the process of how instructions in the genetic code are translated into building proteins. The researchers believe that altering this process during periods when the building blocks for the brain are being laid down may be particularly important in explaining how genetic risk factors for autism get expressed.
Dr Lombardo adds: “Our discovery here meshes nicely with other recent findings that highlight the prenatal period around 15 weeks gestation as a key period when important genetic risk mechanisms for autism are working together to be expressed in the developing brain.”
Professor Baron-Cohen said: “These results should not be taken as a reason to jump to steroid hormone blockers as a treatment as this could have unwanted side effects and may have little to no effect in changing the potentially permanent effects that fetal steroid hormones exert during the early foundational stages of brain development.”
He cautioned further: “Nor should these results be taken as a promising prenatal screening test. There is considerable overlap between the groups and our findings showed differences found at an average group level, rather than at the level of accurately predicting diagnosis for individuals. The value of the new results lies in identifying key biological mechanisms during fetal development that could play important roles in atypical brain development in autism.”
*Within the amniotic fluid the researchers looked at 4 key ‘sex steroid’ hormones that are each synthesized, step-by-step from the preceding one, in the ‘Δ4 sex steroid’ pathway: progesterone, 17α-hydroxy-progesterone, androstenedione and testosterone.
Hypnosis extends restorative slow-wave sleep
Deep sleep promotes our well-being, improves our memory and strengthens the body’s defences. Zurich and Fribourg researchers demonstrate how restorative SWS can also be increased without medication – using hypnosis.
Sleeping well is a crucial factor contributing to our physical and mental restoration. SWS in particular has a positive impact for instance on memory and the functioning of the immune system. During periods of SWS, growth hormones are secreted, cell repair is promoted and the defence system is stimulated. If you feel sick or have had a hard working day, you often simply want to get some good, deep sleep. A wish that you can’t influence through your own will – so the widely held preconception.
Sleep researchers from the Universities of Zurich and Fribourg now prove the opposite. In a study that has now been published in the scientific journal “Sleep”, they have demonstrated that hypnosis has a positive impact on the quality of sleep, to a surprising extent. “It opens up new, promising opportunities for improving the quality of sleep without drugs”, says biopsychologist Björn Rasch who heads the study at the Psychological Institute of the University of Zurich in conjunction with the “Sleep and Learning” project*.
Brain waves – an indicator of sleep quality
Hypnosis is a method that can influence processes which are very difficult to control voluntarily. Patients with sleep disturbances can indeed be successfully treated with hypnotherapy. However, up to now it hadn’t been proven that this can lead to an objectively measurable change in sleep. To objectively measure sleep, electrical brain activity is recorded using an electroencephalogram (EEG). The characteristic feature of slow-wave sleep, which is deemed to have high restorative capacity, is a very even and slow oscillation in electrical brain activity.
70 healthy young women took part in the UZH study. They came to the sleep laboratory for a 90-minute midday nap. Before falling asleep they listened to a special 13-minute slow-wave sleep hypnosis tape over loudspeakers, developed by hypnotherapist Professor Angelika Schlarb, a sleep specialist, or to a neutral spoken text. At the beginning of the experiment the subjects were divided into highly suggestible and low suggestible groups using a standard procedure (Harvard Group Scale of Hypnotic Susceptibility). Around half of the population is moderately suggestible. With this method women achieve on average higher values for hypnotic susceptibility than men. Nevertheless, the researchers expect the same positive effects on sleep for highly suggestible men.
Slow-wave sleep increased by 80 percent
In their study, sleep researchers Maren Cordi and Björn Rasch were able to prove that highly suggestible women experienced 80 percent more slow-wave sleep after listening to the hypnosis tape compared with sleep after listening to the neutral text. In parallel, time spent awake was reduced by around one-third. In contrast to highly suggestible women, low suggestible female participants did not benefit as much from hypnosis. With additional control experiments the psychologists confirmed that the beneficial impact of hypnosis on slow-wave sleep could be attributed to the hypnotic suggestion to “sleep deeper” and could not be reduced to mere expectancy effects.
According to psychologist Maren Cordi “the results may be of major importance for patients with sleep problems and for older adults. In contrast to many sleep-inducing drugs, hypnosis has no adverse side effects”. Basically, everyone who responds to hypnosis could benefit from improved sleep through hypnosis.
* The project “Sleep and Learning” is headed by Professor Björn Rasch from the University of Fribourg and conducted at the Universities of Zurich and Fribourg. The project is financed by the Swiss National Fund and the University of Zurich (main area of clinical research “Sleep and Health”). The goal of the project is to identify psychological and neurophysiological mechanisms underlying the positive role of sleep for our memory and mental health.
(Source: mediadesk.uzh.ch)
Left-handed fetuses could show effects of maternal stress on unborn babies
Fetuses are more likely to show left-handed movements in the womb when their mothers are stressed, according to new research.
Researchers at Durham and Lancaster universities say their findings are an indicator that maternal stress could have a temporary effect on unborn babies, adding that their research highlights the importance of reducing stress during pregnancy.
However, the researchers emphasised that their study was not evidence that maternal stress led to fixed left-handedness in infants after birth. They said that some people might be genetically predisposed to being left-handed and that there are examples where right and left-handedness can switch throughout a person’s life.
Using 4d ultrasound scans, the researchers observed 57 scans of 15 healthy fetuses, recording 342 facial touches.
The fetuses were scanned at four different stages between 24 and 36 weeks of pregnancy. Researchers also asked the mothers of these babies how much stress they had experienced in the four weeks between each of the scans.
The researchers found that the more stress mothers reported, the more frequently fetuses touched their faces with their left hands. They added that a significant number of touches by the fetuses of stressed mothers were done with their left, rather than right hands - therefore fetal touches of their own faces, indicated a left-handed tendency.
As right-handedness is more common in the general population, the researchers had expected to see more of a bias towards right-handed movements in the fetuses as they grew older. The high percentage of left-handed behaviour, observed only when mothers reported being stressed, led them to conclude that maternal stress has an effect on the lateral behaviour of the babies they scanned.
The findings are published in the journal Laterality: Asymmetries of Body, Brain and Cognition.
Lead author Dr Nadja Reissland, in Durham University’s Department of Psychology, said: “Our research suggests that stressed mothers have fetuses who touch their face relatively more with their left hand.
“This suggests maternal stress could be having on effect on the child’s behaviour in the womb and highlights the importance of reducing maternal stress in pregnancy.
“Such measures may include increased emphasis on stopping stressful work early, the inclusion of relaxation classes in pre-natal care and involvement of the whole family in the pre-natal period.
“While we observed a higher degree of left-handed behaviour in the fetuses of stressed mothers than had been expected, we are not saying that maternal stress leads to a child becoming left-handed after birth, as there could be a number of reasons for this.
“The research does suggest, however, that a fetus can detect when a mother is stressed and that it responds to this stress.”
Professor Brian Francis, of Lancaster University, emphasised that the study also showed that overall preference for left or right hand varied considerably from scan to scan within each fetus, though fetuses showed more left-hand movements when mothers reported that they had experienced stress. He said: “Overall, there was no consistent handedness preference being shown by the fetuses, with most fetuses switching in preference at least once over the four scans.”
The researchers added that while mothers were asked to report their stress levels in the four weeks between scans, in practice some might have reported the stress they were experiencing at the time of being surveyed.
Previous research has shown that maternal stress in pregnancy leads to increased levels of cortisol – a hormone produced in response to stress - in mothers that could lead to an altered preference for left-sided or right-sided behaviour in fetuses.
The current study did not assess the stress levels of fetuses and Dr Reissland said that future research could examine cortisol levels in fetuses to further determine the effect of stress on lateral behaviour.
Dr Reissland added that further research was also needed to look at whether or not maternal prenatal stress had longer-term effects on the development of infants and children after birth.
(Source: dur.ac.uk)