Two key brain regions work in tandem like integrated network

Washington, Apr 20 (ANI): Two important areas in the central nervous system— basal ganglia and the cerebellum—are linked together to form an integrated functional network, say researchers at the University of Pittsburgh.

Each subcortical structure houses a unique learning mechanism.

It is believed that the basal ganglia circuits are involved in reward-driven learning and the gradual formation of habits.

On the other hand, cerebellar circuits are thought to contribute to more rapid and plastic learning in response to errors in performance.

“The basal ganglia and the cerebellum are two major subcortical structures that receive input from and send output to the cerebral cortex to influence movement and cognition,” explained senior author Dr. Peter L. Strick, professor of neurobiology and co-director of the Center for the Neural Basis of Cognition, Pitt School of Medicine.

“In the past, these two learning mechanisms were viewed as entirely separate, and we wondered how signals from the two were integrated. Using a unique method for revealing chains of synaptically linked neurons, we have demonstrated that the cerebellum and basal ganglia are actually interconnected and communicate with each other,” said Strick.

The finding not only has important implications for the normal control of movement and cognition, but it also helps to explain some puzzling findings from patients with basal ganglia disorders.

“Our findings provide a neural basis for these findings. In essence, the pathways that we have discovered may enable abnormal signals from the basal ganglia to disrupt cerebellar function. The alterations in cerebellar function are likely to contribute to the disabling symptoms of basal ganglia disorders. Thus, a new approach for treating these symptoms might be to attempt to normalize cerebellar activity,” said Strick.

The findings are available online this week in the Proceedings of the National Academy of Sciences. (ANI)

Babies recognise emotions by 7 months

Washington, Mar 27 (ANI): Babies as young as 7 months old can discern a voice”s emotional state, suggests a new study.

The new research found that the brains of infants demonstrate a sensitivity to the human voice and to emotions communicated through the voice that is remarkably similar to what is observed in the brains of adults.

The study, published by Cell Press in the March 25 issue of the journal Neuron, probes the origins of voice processing in the human brain and may provide important insight into neurodevelopmental disorders such as autism.

Dr. Tobias Grossmann from the Centre for Brain and Cognitive Development at the University of London led the study which was performed in Dr. Angela D. Friederici”s laboratory at the Max Planck Institute for Human Cognitive and Brain Sciences in Germany.

The researchers used near-infrared spectroscopy to investigate when during development regions in temporal cortex become specifically sensitive to the human voice. These specific cortical regions have been shown to play a key role in processing spoken language in adults.

Grossmann and colleagues observed that 7-month-olds but not 4-month-olds showed adult-like increased responses in the temporal cortex in response to the human voice when compared to nonvocal sounds, suggesting that voice sensitivity emerges between 4 and 7 months of age.

Another important question addressed in this study was whether activity in infants” voice-sensitive brain regions is modulated by emotional prosody. Prosody, essentially the “music” of speech, can reflect the feelings of the speaker, thereby helping to convey the context of language. In humans, sensitivity to emotional prosody is crucial for social communication.

The researchers observed that a voice-sensitive region in the right temporal cortex showed increased activity when 7-month-old infants listened to words spoken with emotional (angry or happy) prosody. Such a modulation of brain activity by emotional signals is thought to be a fundamental brain mechanism to prioritize the processing of significant stimuli in the environment.

“Our findings demonstrate that voice-sensitive brain regions are already specialized and modulated by emotional information by the age of 7 months and raise the possibility that the critical neurodevelopmental processes underlying impaired voice-processing reported in disorders like autism might occur before 7 months,” explains Dr. Grossmann. “Therefore, in future work the current approach could be used to assess individual differences in infants” responses to voices and emotional prosody and might thus serve as one of potentially multiple markers that can help with an early identification of infants at risk for a neurodevelopmental disorder.” (ANI)

Fatness can lead to ‘brain shrinkage’

London, Aug 24 (ANI): A new study from University of California in Los Angeles suggests that piling on the pounds can shrink brains of older people, making them more vulnerable to cognitive problems.

According to Paul Thompson, brains of elderly obese people looked 16 years older than the brains of leaner peers.

The research involving 94 people in their 70s showed that people with higher body mass indexes had smaller brains on average, with the frontal and temporal lobes – important for planning and memory, respectively – particularly affected.

While no one knows whether these people are more likely to develop dementia, a smaller brain is indicative of destructive processes that can develop into dementia.

The team also found that the brains of the 51 overweight people were 6 per cent smaller than those of their normal-weight counterparts, on average, and those of the 14 obese people were 8 per cent smaller.

“The brains of overweight people looked eight years older than the brains of those who were lean, and 16 years older in obese people,” New Scientist quoted Thompson as saying.

Thompson suggests that as increased body fat ups the chances of having clogged arteries, which can reduce blood and oxygen flow to brain cells, the resulting reduction in metabolism could cause brain cell death and the shrinking seen.

He said that exercise protects the very brain regions that had shrunk.

“The most strenuous kind of exercise can save about the same amount of brain tissue that is lost in the obese,” he said.

The findings appear in journal Human Brain Mapping. (ANI)

New drug helps rescue memory loss in mice with Alzheimer’s disease

Washington, July 15 (ANI): A drug similar to the one used in clinical trials for treatment of rheumatoid arthritis and psoriasis has been found to be effective against Alzheimer’s disease, say researchers.

The drug called PMX205 has been found to prevent inflamed immune cells from gathering in brain regions with Alzheimer’s lesions called amyloid plaques.

Cell inflammation in these areas accelerates neuron damage, exacerbating the disease.

“We used a multidisciplinary approach combining an understanding of immunology and neurobiology to uncover a completely different target than other therapies,” said Andrea Tenner, lead author of the study that led to the findings, and a molecular biology and biochemistry professor at UCI.

During the study, the researchers fed the mice, genetically altered to develop age-related Alzheimer’s-like symptoms, with PMX205 mixed in drinking water for 12 weeks.

The treatment occurred at an age when plaques were accumulating in their brains.

The researchers then gave the treated mice learning and memory tests and examined their brains for evidence of the disease.

The study showed that Alzheimer’s mice that were not given the drug performed significantly worse on the test than normal mice.

But – in all but one case – the treated Alzheimer’s mice performed almost as well as the normal mice.

Those with the rescued cognitive ability had more than 50 percent fewer Alzheimer’s lesions and inflammatory immune cells than the untreated diseased mice.

The study has been published in the Journal of Immunology. (ANI)

Brain scans can tell ‘honest’ person from ‘dishonest’ one even when both tell the truth

Washington, July 14 (ANI): Researching into the cognitive process involved with honesty, Harvard University psychologists have come to the conclusion that truthfulness depends more on absence of temptation than active resistance to temptation.

Assistant Professor Joshua Greene and graduate student Joe Paxton, the duo that led the study, have revealed that they used neuroimaging to look at the brain activity of people given the chance to gain money dishonestly by lying, and found that honest people showed no additional neural activity when telling the truth.

The researchers say that that observation implied that extra cognitive processes were not necessary to choose honesty.

However, the researchers also found that individuals who behaved dishonestly, even when telling the truth, showed additional activity in brain regions that involve control and attention.

“Being honest is not so much a matter of exercising willpower as it is being disposed to behave honestly in a more effortless kind of way. This may not be true for all situations, but it seems to be true for at least this situation,” says Greene.

The researchers say that they carried out the study to test two theories about the nature of honesty – the “Will” theory, in which honesty results from the active resistance of temptation, and the “Grace” theory in which honesty is a product of lack of temptation.

Writing about their findings in the journal Proceedings of the National Academy of Sciences, they have suggested that the “Grace” theory is true, because the honest participants did not show any additional neural activity when telling the truth.

To prompt participants to lie, the researchers created a cover story about the focus of their study. The research was presented as a study of paranormal ability to predict the future.

The researchers asked those participating in the study to predict the outcomes of a series of coin tosses.

The subjects were told that the research team believed predicting the future was more likely when given a monetary incentive, and when the prediction was not shared in advance of the outcome. That gave the participants the opportunity to lie and say that they had correctly predicted the coin toss to win the money.

The subjects’ honesty was assessed based on whether their number of correct responses was statistically feasible.

According to the researchers, the participants who reported improbably high levels of accuracy were classified as dishonest, and those reporting statistically feasible levels of accuracy were classified as honest.

With the aid of fMRI technique, Greene found that the honest individuals displayed little to no additional brain activity when reporting their prediction of the coin toss. However, the dishonest participants’ brains were most active in control-related brain regions when they chose not to lie.

Greene notes that there was an important distinction between the brain activity when the honest participants told the truth, and when the dishonest participants told the truth.

“When the honest people leave money on the table, you don’t see anything special or extra going on in their brains at all. Whereas, when the dishonest people leave money on the table, that’s when you saw the most robust control network activation,” says the researcher.

The researchers hope that their findings may pave the way for a technique to detect lies by looking at someone’s brain activity, but they also concede that a lot more work must be done before this becomes possible. (ANI)

How brain waves fire in unison while paying attention

Washington, May 29 (ANI): While the neurons in human brains are known to start firing in unison when a person pays attention, scientists have now found the brain centre that controls this neural chorus.

MIT neuroscientists have found that neurons in the prefrontal cortex – the brain’s planning centre – fire in unison and send signals to the visual cortex to do the same, generating high-frequency waves that oscillate between these distant brain regions like a vibrating spring.

The waves, also known as gamma oscillations, have long been associated with cognitive states like attention, learning, and consciousness.

“We are especially interested in gamma oscillations in the prefrontal cortex because it provides top-down influences over other parts of the brain. We know that the prefrontal cortex is affected in people with schizophrenia, ADHD and many other brain disorders, and that gamma oscillations are also altered in these conditions.

Our results suggest that altered neural synchrony in the prefrontal cortex could disrupt communication between this region and other areas of the brain, leading to altered perceptions, thoughts, and emotions,” said senior author Robert Desimone.

The researchers explained this neural synchrony by using the analogy of a crowded party with people talking in different rooms-if individuals raise their voices at random, the noise just becomes louder.

But if a group of individuals in one room chant together in unison, the next room is more likely to hear the message, and if the people in the other room respond in the same way, the two rooms can communicate.

In the study, the researchers looked for patterns of neural synchrony in two “rooms” of the brain associated with attention – the frontal eye field (FEF) within the prefrontal cortex and the V4 region of the visual cortex.

By training two macaque monkeys to watch a monitor displaying multiple objects, and to concentrate on one of the objects, the researchers monitored neural activity in both the above regions of the brain.

They analysed the timing of the neural activity and found that the prefrontal cortex became engaged by attention first, followed by the visual cortex-as if the prefrontal cortex commanded the visual region to snap to attention.

The delay between neural activity in these areas during each wave cycle revealed the speed at which signals travel from one region to the other, which indicated that the two brain regions were talking to one another.

The study has been published in the journal Science. (ANI)

Everyone uses different strategies while making risky decisions

Washington, May 28 (ANI): People use different strategies while making difficult economic decisions, according to a brain activation study by neuroscientists at the Duke University Medical Center.

In the study, the researchers used functional magnetic resonance imaging (fMRI) to observe real-time changes in brain function while participants evaluated complex decision-making problems.

“People in our study, like the population at large, differed in the strategies they use to make economic decisions. What sort of strategy people tended to use could be predicted, surprisingly, by how their brain responded to rewards: if there were large responses to monetary reward in a brain area called the ventral striatum, that person tended to simplify decision problems to only consider winning or losing,” said Scott Huettel, senior author of the study.

“Using studies like this to build a better understanding of how our brains represent our decision strategies may someday allow researchers to use someone’s personal traits – say, an adolescent with high impulsivity, but ongoing depression – to predict the decisions that he or she will make.

“This could lead to many real-world benefits: designing more effective interventions or creating more useful educational material,” he added.

In the study, the researchers scanned 23 participants, and observed real-time changes in brain function as they evaluated complex multi-outcome lotteries.

“Our goal was to come up with a risky decision task that would both discriminate between alternative models of choice and represent something that often happens when people allocate scarce resources to make a risky choice more attractive. It was also nice that the task is complex enough to relate to ‘real-world’ decisions but simple enough to be studied using functional MRI,” said Dr. John W. Payne, the Joseph J. Ruvane, Jr. Professor of Business.

And the results revealed that the brain regions classically associated with “rational” processing, particularly the lateral prefrontal cortex, were most active when subjects used a simplifying strategy inconsistent with traditional rational-choice models.

“This result suggests that it was the type of computation that the participants were doing at any given time that activates a brain region, not whether the thought process is rational or irrational,” said lead author Vinod Venkatraman, from the Department of Psychology and Neuroscience at Duke.

“(The finding) argues strongly against the commonly held notion that there are ‘rational’ and ‘irrational’ parts of the brain,’” added Huettel.

The study also showed that the medial prefrontal region of the brain shapes moment-to-moment changes in the strategies people use to make decisions.

“We all make some decisions opposite to our usual tendencies. When we do so, this brain region comes online and alters activation in other choice-related regions,” said Huettel.

The study has been published online in Neuron. (ANI)

How the brain processes speech

London, May 27 (ANI): A review of human and non-human primate studies suggests that scientists are very close to forming a conclusive theory about the brain processes speech and language.

Dr. Josef Rauschecker of Georgetown University and his co-author Sophie Scott, a neuroscientist at University College, London, say that both human and animal studies have confirmed that speech is processed in the brain along two parallel pathways, each of which run from lower- to higher-functioning neural regions.

The authors describe these pathways as the “what” and “where” streams, which are similar to how the brain processes sight, but are located in different regions.

Both pathways begin with the processing of signals in the auditory cortex, located inside a deep fissure on the side of the brain underneath the temples – the so-called “temporal lobe”.

Information processed by the “what” pathway then flows forward along the outside of the temporal lobe, and the job of that pathway is to recognize complex auditory signals, which include communication sounds and their meaning (semantics).

The “where” pathway is mostly in the parietal lobe, above the temporal lobe, and it processes spatial aspects of a sound – its location and its motion in space – but is also involved in providing feedback during the act of speaking.

Rauschecker says that auditory perception – the processing and interpretation of sound information – is tied to anatomical structures.

“Sound as a whole enters the ear canal and is first broken down into single tone frequencies, then higher-up neurons respond only to more complex sounds, including those used in the recognition of speech, as the neural representation of the sound moves through the various brain regions,” he says.

“In both species, we are using species-specific communication sounds for stimulation, such as speech in humans and rhesus-specific calls in rhesus monkeys. We find that the structure of these communication sounds is similar across species,” he adds.

Rauschecker believes that the findings of this research may ultimately yield some valuable insights into disorders that involve problems in comprehending auditory signals, such as autism and schizophrenia.

“Understanding speech is one of the major problems seen in autism, and a person with schizophrenia hears sounds that are just hallucinations. Eventually, this area of research will lead us to better treatment for these issues,” Rauschecker says.

The study is published in the June issue of Nature Neuroscience. (ANI)

Novel study offers new targets for cocaine addiction

Washington, May 26 (ANI): When given a psychological test, parts of the brain involved in monitoring behaviours and emotions showed different levels of activity in cocaine users relative to non-drug users, a new study has found.

This was when both groups perform equally well on a psychological test.

The study’s results – from a brain-imaging study conducted at the U.S. Department of Energy’s Brookhaven National Laboratory and published online the week of May 25, 2009, by the Proceedings of the National Academy of Sciences – suggest that such impairments may underlie addictive vulnerability, and that treatments aimed at improving these functions could help addicted individuals resist drugs.

“Many studies have found decreased brain activity in drug-addicted individuals relative to healthy control subjects during psychological tests,” said lead author Rita Goldstein, a psychologist at Brookhaven Lab.

“But it’s never been clear if these differences were due to varying levels of interest or ability between the two groups. This is the first study to look at two groups matched for performance and interest – and we still see dramatic differences in the brain regions that play a very significant role in the ability to monitor behavior and regulate emotion, which are both important to resisting drug use.

“Whether these brain differences are an underlying cause or a consequence of addiction, the brain regions involved should be considered targets for new kinds of treatments aimed at improving function and self-regulatory control,” Goldstein said.

To reach the conclusion, researchers studied 17 active cocaine users and 17 demographically matched healthy control subjects. Both groups were trained to push one of four colored buttons corresponding to the color of type used to present words that were either related to drug use (e.g., crack, addict) or neutral household terms. Subjects were given monetary rewards for fast, accurate performance – up to 50 cents for each correct answer on some tests, for a maximum of 75 dollars.

After training, both groups performed equally well on this same test while lying in a magnetic resonance imaging (MRI) scanner, with performance improving when they knew they’d be earning the highest monetary reward. During the tests, the scientists used functional MRI (fMRI) to indirectly measure the amount of oxygen being used by specific regions of the brain, as an indicator of brain activity in those regions.

There were three main differences between the cocaine-addicted subjects and the healthy controls – the cocaine users had reduced activity in a portion of the anterior cingulate cortex that usually becomes more active (compared to a passive baseline) when monitoring behavior.

Second difference was that the cocaine users also had reduced activity in another part of the anterior cingulate cortex that usually becomes less active (compared to a passive baseline) when someone is successfully suppressing emotional feelings.

Last one was that the functions within the behavior-monitoring and emotion-monitoring brain regions were interconnected in the healthy control subjects but not in the addicted individuals.

“When you really have to suppress a powerful negative emotion, like sadness, anxiety or drug craving, activity in this brain region is supposed to decrease, possibly to tune out the background ‘noise’ of these emotions so you can focus on the task at hand,” Goldstein said.

“Our results show that activity in this region indeed went down in the drug-using group, suggesting they were actively trying to suppress craving. Indeed subjects who reported the highest levels of task-induced craving were the least able to suppress activity in this particular brain region.

“This could be because these drug users were still being distracted by background ‘noise’ stimuli, like memories of having taken drugs or anticipation of further use,” Goldstein said. (ANI)

Brain area that makes person sociable identified

Washington, May 20 (ANI): Whether someone is a ‘people-person’ may depend on their brain’s structure, say researchers.

The greater the concentration of brain tissue in certain parts of the brain, the more likely they are to be a warm, sentimental person, Cambridge University researchers added.

To reach the conclusion, Maël Lebreton and colleagues from the Cambridge Department of Psychiatry, in collaboration with Oulu University, Finland, examined the relationship between personality and brain structure in 41 male volunteers.

The volunteers underwent a brain scan using Magnetic Resonance Imaging (MRI). They also completed a questionnaire that asked them to rate themselves on items such as ‘I make a warm personal connection with most people’, or ‘I like to please other people as much as I can’. The answers to the questionnaire provide an overall measure of emotional warmth and sociability called social reward dependence.

The researchers then analysed the relationship between social reward dependence and the concentration of grey matter (brain-cell containing tissue) in different brain regions. They found that the greater the concentration of tissue in the orbitofrontal cortex (the outer strip of the brain just above the eyes), and in the ventral striatum (a deep structure in the centre of the brain), the higher they tended to score on the social reward dependence measure.

The research is published in the European Journal of Neuroscience.

Dr Graham Murray, who is funded by the Medical Research Council and who led the research, said: “Sociability and emotional warmth are very complex features of our personality. This research helps us understand at a biological level why people differ in the degrees to which we express those traits.”

But he cautioned, “As this research is only correlational and cross-sectional, it cannot prove that brain structure determines personality. It could even be that your personality, through experience, helps in part to determine your brain structure.” (ANI)

Kids’ brains are organised differently than adults’

Washington, May 16 (ANI): Children often confront their parents over some or the other issue. Perhaps scientists have now found out why kids show such behaviour.

Researchers at Washington University and Oregon Health and Science University suggest that children’s brains are organised differently than adults’.

However, the same study also provides parents with a rejoinder: hile the overarching organization scheme differs, one of the most important core principals of adult brain organization is present in the brains of children as young as 7.

“Regardless of how tempting it might be to assume otherwise, a normal child’s brain is not inherently disorganized or chaotic. It’s differently organized but at least as capable as an adult brain,” says senior author Dr. Steven E. Petersen, the James McDonnell Professor of Cognitive Neuroscience at Washington University School of Medicine in St. Louis.

Scientists previously revealed four brain networks with varying responsibilities in the adult brain. Two of those networks appear to be co-captains in charge of most voluntary brain function. The networks typically involve tight links between several brain regions that are physically distant from each other.

In the new study, this is where the organizational contrast arises. The researchers observed that instead of having networks made of brain regions that are distant from each other but functionally linked, most of the tightest connections in a child’s brain are between brain regions that are physically close to each other.

Lead researchers Dr. Damien A. Fair, a former Washington University graduate student who is now associated with Oregon Health and Science University, and Alexander L. Cohen, a current Washington University graduate student, directed analysis of data from 210 subjects ranging from 7 to 31 years old.

“We took a group of the youngest subjects, analysed their results, then dropped data from the youngest and added data from the next-oldest and redid the analysis until we had worked our way through all subjects. The result was a detailed movie of how the organizational transition from a child’s brain to an adult’s brain takes place. It clearly shows a switch from localized networks based on physical proximity to long-distance networks centred on functionality,” Fair says.

Scientists already knew that children had many fewer long-distance links among brain regions than adults, but when they looked more closely, they found there were enough of these links and nodes with multiple connections to establish small-world organization.

The researchers set the lower limit for study subjects at 7 years of age because the brain is approximately 95 percent of its adult size at this age, but they are currently examining ways to adapt the study to the changing physical geography of younger brains.

They have also begun looking at the same phenomena in subjects with brain injuries and developmental disorders.

The study has been published online in PLoS Computational Biology. (ANI)

Kids’ brains are organised differently than adults’

Washington, May 16 (ANI): Children often confront their parents over some or the other issue. Perhaps scientists have now found out why kids show such behaviour.

Researchers at Washington University and Oregon Health and Science University suggest that children’s brains are organised differently than adults’.

However, the same study also provides parents with a rejoinder: hile the overarching organization scheme differs, one of the most important core principals of adult brain organization is present in the brains of children as young as 7.

“Regardless of how tempting it might be to assume otherwise, a normal child’s brain is not inherently disorganized or chaotic. It’s differently organized but at least as capable as an adult brain,” says senior author Dr. Steven E. Petersen, the James McDonnell Professor of Cognitive Neuroscience at Washington University School of Medicine in St. Louis.

Scientists previously revealed four brain networks with varying responsibilities in the adult brain. Two of those networks appear to be co-captains in charge of most voluntary brain function. The networks typically involve tight links between several brain regions that are physically distant from each other.

In the new study, this is where the organizational contrast arises. The researchers observed that instead of having networks made of brain regions that are distant from each other but functionally linked, most of the tightest connections in a child’s brain are between brain regions that are physically close to each other.

Lead researchers Dr. Damien A. Fair, a former Washington University graduate student who is now associated with Oregon Health and Science University, and Alexander L. Cohen, a current Washington University graduate student, directed analysis of data from 210 subjects ranging from 7 to 31 years old.

“We took a group of the youngest subjects, analysed their results, then dropped data from the youngest and added data from the next-oldest and redid the analysis until we had worked our way through all subjects. The result was a detailed movie of how the organizational transition from a child’s brain to an adult’s brain takes place. It clearly shows a switch from localized networks based on physical proximity to long-distance networks centred on functionality,” Fair says.

Scientists already knew that children had many fewer long-distance links among brain regions than adults, but when they looked more closely, they found there were enough of these links and nodes with multiple connections to establish small-world organization.

The researchers set the lower limit for study subjects at 7 years of age because the brain is approximately 95 percent of its adult size at this age, but they are currently examining ways to adapt the study to the changing physical geography of younger brains.

They have also begun looking at the same phenomena in subjects with brain injuries and developmental disorders.

The study has been published online in PLoS Computational Biology. (ANI)

Our brains remain much more active while daydreaming than earlier thought

Washington, May 12 (ANI): Out brains are much more active while daydreaming than previously thought, if a new study is to be believed.

Conducted by researchers at the University of British Colombia, the study has shown that activity in numerous brain regions increases when a person’s mind wanders.

It has also found that brain areas linked with complex problem-solving, which were previously thought to go dormant while daydreaming, remain highly active during such episodes.

“Mind wandering is typically associated with negative things like laziness or inattentiveness. But this study shows our brains are very active when we daydream – much more active than when we focus on routine tasks,” says lead author, Prof. Kalina Christoff, UBC Department of Psychology.

During the study, the researchers placed the subjects inside an fMRI scanner, where they performed the simple routine task of pushing a button when numbers appear on a screen.

The research team tracked the participants’ attentiveness moment-to-moment through brain scans, subjective reports from the subjects, and by tracking their performance on the task.

They found daydreaming to be an important cognitive state in which one may unconsciously turn one’s attention from immediate tasks to sort through important problems.

Scientists have to date thought that the brain’s “default network” – which is linked to easy, routine mental activity and includes the medial prefrontal cortex (PFC), the posterior cingulate cortex and the temporoparietal junction – is the only part of the brain that is active while a person’s mind wanders.

However, the latest study has shown that the brain’s “executive network” – associated with high-level, complex problem-solving and including the lateral PFC and the dorsal anterior cingulate cortex – also gets activated while people daydream.

“This is a surprising finding, that these two brain networks are activated in parallel. Until now, scientists have thought they operated on an either-or basis – when one was activated, the other was thought to be dormant,” says Christoff.

According to the researchers, the less the participants were aware that their mind was wandering, the more both networks were activated.

The quantity and quality of brain activity suggests that people struggling to solve complicated problems might be better off switching to a simpler task, and letting their mind wander.

“When you daydream, you may not be achieving your immediate goal – say reading a book or paying attention in class – but your mind may be taking that time to address more important questions in your life, such as advancing your career or personal relationships,” says Christoff.

A research article on the study has been published in the Proceedings of the National Academy of Sciences. (ANI)

Scientists studying brains at rest to gain fresh insights into mental health disorders

Washington, May 8 (ANI): Hoping to some day develop new tools for diagnosing mental health disorders and monitoring the progress of their treatments, scientists have now turned to uncovering new information about the mind by studying brains while they are at rest.

Researchers at Oregon Health and Science University are running one such research project in collaboration with experts at Washington University in St. Louis, the latest findings of which have been published in the journal the Public Library of Science Computational Biology.

“For years, the vast majority of scientists studying human functional brain organization have focused on how activity changes when engaged in specific tasks,” said Dr. Damien Fair, a postdoctoral research scientist in psychiatry, OHSU School of Medicine.

“However now we know there are several regions in the brain that continue to interact while a person is supposedly at rest – sort of like a car that idles at a stoplight. Our lab is studying these interactions, or spontaneous brain activity, while the brain is at rest. We think that this approach will eventually help us distinguish typical function from atypical function and therefore help more rapidly diagnose and appropriately treat mental disorders,” the researcher said.

The researchers use a form of magnetic resonance imaging (MRI), known as functional connectivity MRI, to study the brains of a large group of subjects while they were at rest.

The researchers said that their efforts led to the identification of brain regions that spontaneously activated together while the subjects were at rest.

According to the, these regions operate in tandem with one another, and group into regional networks.

“After observing a large group of study subjects between the ages of 7 and 31, we witnessed an interesting phenomenon. Communications between brain regions seem to be localized in children, but over time, regional communication becomes distributed across the whole brain. Despite these differences, children’s brains are still very efficient. As with the adults, the brains in the children were still organized like a ‘small world,’” added Fair.

The researchers will next compare functional connectivity MRI images taken from typically developing human subjects with images taken from human subjects with mental disorders, as they believe that doing so can help them pinpoint distinct functional differences that may one day assist physicians in diagnosing certain disorders.

“One of our key interest areas is ADHD. ADHD is one of the most widely diagnosed mental disorders in children, yet diagnosing it can be very difficult because diagnosis is based on patient and parent interviews and observational studies. Having a more tangible form of diagnosis – such as an MRI screening tool would be tremendously valuable to patients and physicians,” said Fair. (ANI)

‘Free will’ spot found in brain

London, May 8 (ANI): Researchers in France have identified the place where free will resides.

Lead scientist Angela Sirigu, a neuroscientist at the CNRS Cognitive Neuroscience Centre in Bron, say that the place lies towards the back of the brain called the parietal cortex.

The finding was made when a neurosurgeon electrically jolted this region in patients undergoing surgery, they felt a desire to wiggle their finger, roll their tongue or move a limb.

Stronger electrical pulses convinced patients they had actually performed these movements, although their bodies remained motionless, reports New Scientist.

“What it tells us is there are specific brain regions that are involved in the consciousness of your movement,” says Sirigu.

Sirigu’s team, including neurosurgeon Carmine Mottolese, performed the experiments on seven patients undergoing brain surgery to remove tumours.

In all but one case, the cancers were located far from the parietal cortex and other areas that Mottolese stimulated.

The team’s work points to two brain areas involved in the decision to move a limb and then execute the action.

Sirigu believes that the parietal cortex makes predictions about future movements and sends instructions to another brain area, the premotor cortex, which returns the outcome of the movement to the parietal cortex.

The study has been published in the journal Science. (ANI)

Sex hormone oestrogen controls sound processing in the brain

Washington, May 6 (ANI): University of Rochester scientists in New York have found that sex hormone oestrogen controls how the brain processes sounds.

This is the first time that any study has shown that a sex hormone can directly affect auditory function.

The researchers say that their study points toward the possibility that oestrogen controls other types of sensory processing as well.

According to them, understanding how oestrogen changes the brain’s response to sound may open the door to new ways of treating hearing deficiencies.

“We’ve discovered estrogen doing something totally unexpected. We show that estrogen plays a central role in how the brain extracts and interprets auditory information. It does this on a scale of milliseconds in neurons, as opposed to days, months or even years in which estrogen is more commonly known to affect an organism,” says Raphael Pinaud, assistant professor of brain and cognitive sciences at the University of Rochester and lead author of the study.

The researcher has revealed that past studies have already hinted at a connection between oestrogen and hearing in women who have its low levels, something that often occurs after menopause.

He, however, insists that no one actually knew that oestrogen plays such a direct role in determining auditory functions in the brain.

“Now it is clear that estrogen is a key molecule carrying brain signals, and that the right balance of hormone levels in men and women is important for reasons beyond its role as a sex hormone,” says Pinaud.

Working in collaboration with Assistant Professor Liisa Tremere and postdoctoral fellow Jin Jeong, Pinaud showed that increasing oestrogen levels in brain regions, which process auditory information, caused heightened sensitivity of sound-processing neurons, which encoded more complex and subtle features of the sound stimulus.

He reveals that when the actions of oestrogen were blocked, or brain cells were prevented from producing the hormone within auditory centres, the signalling that is necessary for the brain to process sounds shut down.

His team have also shown that oestrogen is required to activate genes that instruct the brain to lay down memories of those sounds.

“It turns out that estrogen plays a dual role. It modulates the gain of auditory neurons instantaneously, and it initiates cellular processes that activate genes that are involved in learning and memory formation,” says Pinaud.

Pinaud and his colleagues made these findings while studying how oestrogen may help change neuronal circuits to form memories of familiar songs in a type of bird typically used to understand the biology of vocal communication.

“Based on our findings we must now see estrogen as a central regulator of hearing. It both determines how carefully a sound must be processed, and activates intracellular processes that occur deep within the cell to form memories of sound experiences,” he says.

The researchers will continue their work studies to find out how neurons adapt their functionality when encountering new sensory information, and how these changes may ultimately enable the formation of memories.

They also will continue exploring the specific mechanisms by which estrogen might impact these processes.

“While we are currently conducting further experiments to confirm it, we believe that our findings extrapolate to other sensory systems and vertebrate species,” says Pinaud. “If this is the case, we are on the way to showing that estrogen is a key molecule for processing information from all the senses.”

The study has been published in The Journal of Neuroscience. (ANI)

Racing games ‘lead to aggressive behaviour’

London, April 12 (ANI): Console driving games leave you feeling more aggressive than violent shoot ‘em ups, says a new study.

Previous studies have linked violence in video games to aggression. However, the new study has suggested that video games don’t have to be violent to trigger an emotional response.

It found that driving games could activate more brain regions involved in emotional processing than shoot ‘em ups.

For the study, Simon Goodson and Sarah Pearson of the University of Huddersfield in the UK recruited 30 adults aged between 18 and 45 to play either a competitive driving game, a shoot ‘em up or virtual table tennis against computer-generated competitors.

Brain activity, heart rate and breathing were all monitored during the game, and a questionnaire afterwards assessed their levels of anger, hostility and aggression.

The volunteers scored normally for aggression after playing the driving and shoot ‘em up games, while those playing the table tennis game scored as slightly less aggressive than the average for the volunteers.

However, when it came to brain activity, the driving game caused a significant increase in the temporal lobe, an area of the brain linked to emotional processing.

“It cannot be assumed that aggression is solely related to violent content,” New Scientist quoted Goodson, as saying.

The study was presented at a British Psychological Society meeting in Brighton last week. (ANI)

Adult human brain processes fractions ‘intuitively’

Washington, April 8 (ANI): Fractions are often considered a major stumbling block in math education, but the adult brain encodes them automatically without conscious thought, says a new study.

The study, conducted by researchers Simon Jacob, MD, and Andreas Nieder, PhD, at the University of Tübingen in Germany, has shown that cells in the intraparietal sulcus (IPS) and the prefrontal cortex – brain regions important for processing whole numbers – are tuned to respond to particular fractions.

The findings suggest that adults have an intuitive understanding of fractions and may aid in the development of new teaching techniques.

“This new study challenges the notion that children must undergo a qualitative shift in order to understand fractions and use them in calculations. The findings instead suggest that fractions are built upon the system that is employed to represent basic numerical magnitude in the brain,” Daniel Ansari, PhD, at the University of Western Ontario in Canada, an expert on numerical cognition in children and adults who was not affiliated with the study.

For the study, the research team scanned the brains of adult participants as they watched fractions flashed on a screen.

The researchers used a technique called functional MRI adaptation (fMRA) to identify brain regions that adapt – or show decreased activity – to the same stimulus presented over and over again.

When the researchers rapidly and repeatedly presented study participants with fractions that equaled approximately 1/6, they found decreased activation in the IPS and prefrontal cortex.

Then, the researchers showed the participants fractions that deviated from 1/6. The more the fraction differed from 1/6, the greater the activity in IPS cells.

The rapid presentation of each fraction and small variations in fraction value ensured that study participants directly processed the fractions, rather than calculating their values.

These findings suggest that fractions automatically activate the IPS and prefrontal cortex in adults.

The researchers found that distinct groups of cells in these brain regions responded to different fraction values. Moreover, the cells responded the same way, whether fractions were presented as either numbers (1/4) or words (one-fourth).

“These experiments change the way we should think about fractions. We have shown that our highly-trained brains represent fractions intuitively, a result that could influence the teaching of arithmetic and mathematics in schools,” said study author Jacob.

The research has been published in the April 8 issue of The Journal of Neuroscience. (ANI)

Double hand transplant helps regain lost brain control

London, Apr 7 (ANI): In a novel study, French scientists have found that transplanted hands successfully activate the brain region linked to muscular movement, thus raising the prospect of regaining full movement.

It is known that motor cortex, the part of the brain region that maintains a physical map of the body with different areas registering sensations in different body parts.

When the hand gets amputated the brain region linked to it goes unused.

To stop from remaining unused, the brain rewires itself thus taking over the region formerly dominated by the hand.

For the study, the research team led by Angela Sirigu, at the Institute for Cognitive Science in Lyon, France used magnetic pulses to stimulate these areas in two people who had undergone double hand transplants.

They found that muscles in the new hands reacted to the stimulation, thus making it evident that the brain had fully accepted them.

“We can see the brain directly activating the new transplanted muscles,” New Scientist quoted Sirigu as saying.

However, the left hand was quicker in regaining the movement than the right one.

In one case, the left hand re-acquired a significant “presence” in the brain after 10 months while the right hand took 26 months.

The researchers believe this could be due to the varying flexibility of the brain regions responsible for each hand.

They believe that because both subjects were right-handed, the brain regions dominated by the right hand were more active prior to amputation and therefore not as flexible to rearrangement.

But the areas corresponding to the left hand were commandeered to a greater extent by other body parts. This may have led to greater flexibility in the left-hand region, thus allowing signals from the transplanted left hand to be integrated faster.

The study appears in Proceedings of the National Academy of Sciences. (ANI)

Brain’s ‘wisdom centre’ found

London, Apr 5 (ANI): The seat of human wisdom has been identified by researchers at University of California in San Diego.

Using sophisticated brain scanning techniques, scientists were able to pinpoint parts of the brain that guide people when they face difficult moral dilemmas.

Boffins have found that humans respond by activating areas associated with the primitive emotions of sex, fear and anger as well as their capability for abstract thought, reports The Telegraph.

The findings are to be published in the Archives of General Psychiatry.

Dilip Jeste, professor of psychiatry and neuroscience at the University of California in San Diego, said: “Our research suggests there may be a basis in neurobiology for wisdom’s most universal traits.”

The research team, including Jeste and Thomas Meeks, found that pondering a simple situation calling for altruism activated the medial prefrontal cortex, an area linked to intelligence and learning. However, when faced with a difficult moral judgment, the brain activated other areas including those connected with both rational thought and primitive emotions.

Meek said: “Several brain regions appear to be involved in different components of wisdom. It seems to involve a balance between more primitive brain regions, like the limbic system, and the newest ones, such as the prefrontal cortex.” (ANI)