Dementia ‘can take away meaning of flavors’

Washington, May 16 (ANI): Dementia sufferers can lose their capacity to understand sights, sounds and words. And in some cases, researchers say, they have a harder time identifying flavors and determining whether a certain flavor combination would generally be considered unusual.

According to the boffins, those with a specific type of dementia, called semantic dementia, face such a problem, reports Live Science.

The new study suggests that this type of semantic dementia causes a semantic deficit across the board (semantics is the study of meaning).

“It”s quite interesting and unexpected that one would find these sensory signals behaving in the same way words or music might behave,” said study researcher Jason Warren, of the University College London. “Flavor information is one example of a complex environmental signal that people can lose understanding about, it”s part of a more general problem,” he said.

The results are published in the June issue of the journal Cortex. (ANI)

Brain may use clot-busting drug naturally to offer protection against stroke

Washington, May 6 (ANI): The clot-busting stroke drug tPA (tissue-type plasminogen activator) can act as a neuroprotectant and may form the keystone of an adaptive response to a reduction in blood flow, say scientists from Emory University School of Medicine.

In a new study, the boffins have shown that certain parts of the brains of mice lacking the gene for tPA are more vulnerable to stroke. In addition, tPA can protect neurons in the same part of the brain from the stress of hypoxia (low oxygen).

The results are published online in the Journal of Clinical Investigation.

“tPA is not only a drug, it is a natural protein produced in response to hypoxia,” says senior author Manuel Yepes, MD, associate professor of neurology at Emory University School of Medicine. “If you look at the parts of brain where the gene for tPA is turned on the most, one of these is the hippocampus. It is well known that the hippocampus is especially vulnerable to hypoxia compared with other regions of the brain. We believe there is a reason for this overlap.”

The hippocampus is a structure in the middle of the brain thought to be responsible for memory formation. In mice lacking the gene for tPA, neurons in the hippocampus are more vulnerable to dying after a short simulated stroke lasting 20 minutes, Yepes and his colleagues found. In the laboratory, pre-treatment with tPA protects hippocampal neurons in culture from hypoxia. In contrast, tPA has the opposite effect on neurons from the cortex.

tPA”s protective properties suggest that it may be playing a role in a process called “ischemic preconditioning,” where a less-than-lethal stroke can protect the brain against a later repeat, Yepes says. tPA”s effects on the blood-brain barrier can be seen as a way to get more blood to a deprived part of the brain. (ANI)

Lottery game can assess brain damage following stroke

Washington, Apr 29 (ANI): A lottery game could help to assess brain damage in people who have had a stroke, say researchers.

Patients recovering from stroke sometimes behave as if completely unaware of one half of the world: colliding with obstacles on their left, or eating food only from the right side of their plate.

This puzzling phenomenon is termed “spatial neglect” and it affects roughly 45 percent of patients suffering from a stroke in the right side of the brain. The condition can indicate a long road to recovery, but researchers have now developed a quick and simple lottery game, which can be used to assess the extent of these symptoms and potentially aid the design of rehabilitation programmes.

The findings are reported in the May 2010 issue of Elsevier”s Cortex.

Dr Tobias Loetscher (University of Melbourne) and colleagues studied a group of stroke patients, using tests based on a simple lottery game in which patients first chose six lottery numbers by marking them with a pencil on a real lottery ticket. Predictably, the patients with spatial neglect tended to pick numbers located on the right-hand side of the ticket, neglecting those on the left.

However, spatial neglect does not only affect a patient”s interaction with the “real world”; it can also affect spatial imagination. In the second part of the test, patients were asked to spontaneously name six numbers without the aid of a lottery ticket. It is commonly believed that when we think of numbers we visualize them arranged along a mental number line with numbers increasing from left to right. The results of the study showed some patients picking only large numbers, indicating that they were unable to access the left side of mental images.

The information obtained from such simple bed-side tests could potentially be used to tailor effective rehabilitation procedures, which suit the individual patient. For example, patients who show signs of spatial neglect when marking numbers on the real lottery ticket, but not when picking numbers from their imagination, could be taught how to scan the missing part of their “real world”, since they may be able to envisage it in their minds. (ANI)

Network problem harms brain in Alzheimer’s disease!

Mon, Mar 29 12:02 PM

In what could pave the way for new strategies for early diagnosis and effective treatment of Alzheimer’s, scientists have found that the disease makes parts of the brain shrink “as messages fail to get through”.

The findings, published in the ‘Neurology’ journal, suggest a build-up of deposits of the protein amyloid-beta in a region of the brain known as temporal inferior cortex which is connected to the hippocampus involved in memory.

Alzheimer’s disease is characterised by two factors –a build-up of amyloid-beta plaques in the brain, and a loss of neurons.

Lead scientist Dr Cassandra Szoeke of CSIRO said the puzzle for them was that the parts of the brain that had shrunk (atrophied) due to neuron loss were not the same as those showing increased deposits of amyloid-beta.

Using MRI scans to study Alzheimer’s disease affected brain tissue, the scientists found that shrinking (atrophy) of the hippocampus was associated with plaque deposits in the temporal inferior cortex.

The results indicate that the increased accumulation of amyloid in temporal inferior cortex disrupts connections with the hippocampus, causing the neurons to die, say the scientists.

“By helping to better understand the mechanisms involved in the progression of the disease, the study may guide the development of new strategies for early diagnosis,” Dr Szoeke said.
Agencies

Scientists develop robotic hand that ‘restores sense of touch’

London, Sept 10 (ANI): The first robotic hand to give amputees a sense of touch has been created by Swedish scientists.

When pressed against an object the 40 sensors in the Smarthand get activated. It also has four motors, which move the thumb and fingers.

They stimulate nerves in the arm to activate the appropriate part of the brain. This allows patients to feel objects they are holding, reports Sky News.

“It’s a feeling I have not had in a long time,” said Robin af Ekenstam, the first amputee to try the hand.

“When I grab something tightly I can feel it in the fingertips. It’s strange since I don’t have them any more! It’s amazing,” he added.

The motors are connected to nerves in the arm that once moved Robin’s real digits. Thanks to the “hand”, he’s able to pick up a plastic water bottle, without crushing it, and pour himself a drink.

Professor Goran Lundborg, a surgeon at Malmo University Hospital, said the artificial hand was a significant advance.

“If you find the right spot the correct areas of the brain cortex will be activated. If you put pressure on the index finger of the artificial hand then the index finger area of the brain will be activated,” he said.

The research is funded by the European Commission. (ANI)

Healthy older brains not smaller than younger ones

Washington, Sept 8 (ANI): The belief that healthy older brains are substantially smaller than younger brains has been deemed incorrect by Dutch researchers.

The authors suggest that previous findings may have overestimated atrophy and underestimated normal size for the older brain.

The new study tested participants in Holland’s long-term Maastricht Aging Study who were free of neurological problems such as dementia, Parkinson’s disease or stroke.

Once participants were deemed otherwise healthy, they took neuropsychological tests, including a screening test for dementia, at baseline and every three years afterward for nine years.

MRI scans were used to measure seven different parts of the brain, including the memory-laden hippocampus, the areas around it, and the frontal and cingulate areas of the cognitively critical cortex.

The participants were later divided into two groups: one group with 35 cognitively healthy people who stayed free of dementia (average starting age 69.1 years), and the other group with 30 people who showed substantial cognitive decline but were still dementia-free (average starting age 69.2 years).

In contrast to the 35 people who stayed healthy, the 30 people who declined cognitively over study-period showed a significant effect for age in the hippocampus and parahippocampal areas, and in the frontal and cingulate cortices.

In short, among the people whose cognition got worse, older participants had smaller brain areas than younger participants.

Thus, the seeming age-related atrophy in gray matter more likely reflected pathological changes in the brain that underlie significant cognitive decline than aging itself, wrote the authors.

As long as people stay cognitively healthy, the researchers believe that the gray matter of areas supporting cognition might not shrink much at all.

If future longitudinal studies find similar results, our conception of ‘normal’ brain aging may become more optimistic,” said lead author Saartje Burgmans, who is due to receive her PhD later this year.

The study appears in journal Neuropsychology. (ANI)

Playing Tetris could boost brain power

London, September 2 (ANI): Playing Tetris may help increase brain efficiency, says a new research.

Researchers from Mind Research Network in Albuquerque, New Mexico, examined the effects of practice in the brain using two image techniques.

Dr. Rex Jung and Dr. Richard Haier, co-investigators in the Tetris study, made use of brain imaging and Tetris to see if practice makes the brain efficient because it increases gray matter.

Jung, a clinical neuropsychologist, said: “One of the most surprising findings of brain research in the last five years was that juggling practice increased gray matter in the motor areas of the brain.

“We did our Tetris study to see if mental practice increased cortical thickness, a sign of more gray matter. If it did, it could be an explanation for why previous studies have shown that mental practice increases brain efficiency.

“More gray matter in an area could mean that the area would not need to work as hard during Tetris play.”

Haier, lead author of a 1992 research that discovered practicing Tetris led to greater brain efficiency, also added: “We were excited to see cortical thickness differences between the girls that practiced Tetris and those that did not.

“But, it was surprising that these changes were not where we saw more efficiency. How a thicker cortex and increased brain efficiency are related remains a mystery.”

The study has been published in the open access journal BMC Research Notes. (ANI)

Our nostrils share a ‘smelly’ rivalry

Washington, Aug 21 (ANI): Our nostrils may look like a happy pair, but according to a new study, when they pick up conflicting scents, the nose holes become deadly rivals.

The study, published online in Current Biology, a Cell Press publication, explains that when the nose encounters two different scents simultaneously, the brain processes them separately through each nostril in an alternating fashion.

The finding by researchers at Rice University in Houston is the first demonstration of “perceptual rivalry” in the olfactory system.

“Our discovery opens up new avenues to explore the workings of the olfactory system and olfactory awareness,” said Denise Chen, assistant professor of psychology, who coauthored the research paper with graduate student Wen Zhou.

For the study, 12 volunteers sampled smells from two bottles containing distinctively different odors. One bottle had phenyl ethyl alcohol, which smells like a rose, and the other had n-butanol, which smells like a marker pen.

The bottles were fitted with nosepieces so that volunteers could sample both scents simultaneously-one through each nostril.

During 20 rounds of sampling, all 12 participants experienced switches between smelling predominantly the rose scent and smelling predominantly the marker scent. Some experienced more frequent and drastic switches than others, but there was no predictable pattern of the switch across the whole group of volunteers or within individuals.

Chen said this “binaral rivalry” between the nostrils resembles the rivalry that occurs between other pairs of sensory organs.

When the eyes simultaneously view two different images-one for each eye-the two images are perceived in alternation, one at a time. And when alternating tones an octave apart are played out of phase to each ear, most people experience a single tone that goes back and forth from ear to ear.

In the laboratory setting in which each nostril simultaneously received a different smell, the participants experienced an “olfactory illusion,” she said.

“Instead of perceiving a constant mixture of the two smells, they perceive one of the smells, followed by the other, in an alternating fashion, as if the nostrils were competing with one another. Although both smells are equally present, the brain attends to predominantly one of them at a time,” the expert added.

“The binaral rivalry involves adaptations at the peripheral sensory neurons and in the cortex,” Chen said.

“Our work sets the stage for future studies of this phenomenon so we can learn more about the mechanisms by which we perceive smells,” the expert said.

In binaral rivalry, the tug-of-war between dominance and suppression of the olfactory perception exists only in the mind of the person who smells the odors, while the physical properties of the olfactory stimuli remain unchanged, Chen said. This gives humans the rare opportunity to dissociate olfactory perception and physical stimulation. (ANI)

High levels of reward chemical dopamine favour adventurous choices

London, July 28 (ANI): If you are among those who love to try a new dish in a restaurant rather than going for the tried and tested one, then the level of the reward chemical dopamine you have in a brain region are probably high, according to a study.

A gene, called COMT, codes for an enzyme that breaks down dopamine in the prefrontal cortex.

People with a less efficient version of COMT have more dopamine in this region, and this makes them good at storing multiple ideas in the short term.

In order to determine whether COMT affects decision-making too, Michael Frank and colleagues at Brown University in Providence, Rhode Island, asked volunteers to stop a stop-clock hundreds of times in exchange for points.

They observed that sometimes stopping it early garnered most points, while at other times a late response did best.

That forced volunteers to keep changing their strategies, reports New Scientist magazine.

Those with the inefficient version of COMT were more likely than people with the active version to switch strategies to try to do even better

The team concluded that high levels of dopamine in the prefrontal cortex make people more adventurous, even when the status quo is fine.

The study has been published in Nature Neuroscience. (ANI)

How noise affects nervous system’s ability to transcribe sounds key to reading skills

Washington, July 14 (ANI): A new study conducted by Northwestern University researchers offers an unparalleled look at how noise affects the nervous system’s ability to transcribe sounds whose subtle differences are key to success with language and reading.

The study suggests that distinguishing such sounds is too much to ask of the nervous system of a subset of poor readers whose hearing is fine, but whose brains have trouble differentiating the “ba,” “da” and “ga” sounds in a noisy environment.

“The ‘b,’ ‘d’ and ‘g’ consonants have rapidly changing acoustic information that the nervous system has to resolve to eventually match up sounds with letters on the page,” said Nina Kraus, Hugh Knowles Professor of Communication Sciences and Neurobiology and director of Northwestern’s Auditory Neuroscience Laboratory, where the work was performed.

According to the researcher, the brain’s unconscious faulty interpretation of sounds makes a big difference in how words ultimately will be read.

“What your ear hears and what your brain interprets are not the same thing,” Kraus said.

This is the first time that any study has shown an unambiguous relationship between reading ability and neural encoding of speech sounds, which previous work has shown present phonological challenges for poor readers.

Published in the online edition of the Proceedings of the National Academy of Sciences (PNAS), the study focuses on what is happening in the brainstem, an evolutionarily ancient part of the brain that scientists in the not too distant past believed simply relayed sensory information from the ear to the cortex.

The researchers focused on the sensory system, and demonstrated that the technology developed during the last decade in the Kraus lab offered a neural metric sensitive enough to pick up how the nervous system represents differences in acoustic sounds in individual subjects, rather than, as in cortical-response studies, in groups of people.

What is significant to note is the fact that this metric reflects the negative influence of background noise on sound encoding in the brain.

“There are numerous reasons for reading problems or for difficulty hearing speech in noisy situations, and we now have a metric that is practically applicable for measuring sound transcription deficits in individual children. Auditory training and reducing background noise in classrooms, our research suggests, may provide significant benefit to poor readers,” said Kraus, the senior author of the study.

During the study, the researchers attached electrodes to the scalps of children with good and poor speech-in-noise perception skills, and delivered sounds through earphones to measure the nervous system’s ability to distinguish between “ba,” “da” and “ga”.

In another part of the study, sentences were presented in increasingly noisy environments, and children were asked to repeat what they heard.

“In essence, the kids were called upon to do what they would do in a classroom, which is to try to understand what the kid next to them is saying while there is a cacophony of sounds, a rustling of papers, a scraping of chairs,” Kraus said.

The researcher says that in a typical neural system, there is a clear distinction in how “ba,” “da” and “ga” are represented, and the information is more accurately transcribed in good readers and children who are good at extracting speech presented in background noise.

“So if a poor reader is having difficulty making sound-to-meaning associations with the ‘ba,’ ‘da’ and ‘ga’ speech sounds, it will show up in the objective measure we used in our study,” Kraus said.

Reflecting the interaction of cognitive and sensory processes, the brainstem response is not voluntary.

“The brainstem response is just what the brain does based on our auditory experience throughout our lives, but especially during development. The way the brain responds to sound will reflect what language you speak, whether you’ve had musical experience and how you have used sounds,” Kraus said. (ANI)

Gene-brain activity pattern combo behind difficult-to-hush babies

Washington, July 14 (ANI): People finding it difficult to soothe their babies need not worry about their parenting skills anymore, for a new study suggests that children’s temperament may be due in part to a combination of a certain gene and a specific pattern of brain activity.

Writing about their findings in the journal Psychological Science, McMaster University researcher Louis Schmidt points out that the pattern of brain activity in the frontal cortex of the brain has been associated with various types of temperament in children.

He highlights the fact that infants who have more activity in the left frontal cortex are characterized as temperamentally “easy” and are easily calmed down, while those with greater activity in the right half of the frontal cortex are temperamentally “negative” and are easily distressed and more difficult to soothe.

In the current study, he and his colleagues focused on the interaction between brain activity and the DRD4 gene to see whether it predicted children’s temperament.

According to background information in the Psychological Science article, previous studies have linked the longer version of this gene to increased sensory responsiveness, risk-seeking behaviour, and attention problems in children.

In the present study, brain activity was measured in 9-month-old infants through electroencephalography (EEG) recordings. When the children were 48 months old, their mothers completed questionnaires regarding their behaviour and DNA samples were taken from the children for analysis of the DRD4 gene.

Schmidt says that the results reveal interesting relations among brain activity, behaviour, and the DRD4 gene.

He says that among the children with more activity in the left frontal cortex at 9 months, those who had the long version of the DRD4 gene were more soothable at 48 months than those who possessed the shorter version of the gene.

However, he adds, the children with the long version of the DRD4 gene, who had more activity in the right frontal cortex, were the least soothable and exhibited more attention problems compared to the other children.

Schmidt says that these findings suggest that the long version of the DRD4 gene may act as a moderator of children’s temperament.

“(The) results suggest that it is possible that the DRD4 long allele plays different roles (for better and for worse) in child temperament (depending on internal conditions or the environment inside their bodies),” note the authors.

They conclude that the pattern of brain activity-that is, greater activation in left or right frontal cortex-may influence whether this gene is a protective factor or a risk factor for soothability and attention problems.

The authors cautioned that there are likely other factors that interact with these two measures in predicting children’s temperament. (ANI)

How a plant hormone is crucial in controlling root growth

London, July 8 (ANI): An international group of scientists, led by the Centre for Plant Integrative Biology at The University of Nottingham, UK, has shed light on how a plant hormone is crucial in controlling the growth of plant roots.

Plant growth is driven by an increase in two factors: the number of cells, and their size.

It is already known that the plant hormone gibberellin controls how root cells elongate as the root grows in the model plant Arabidopsis thaliana.

Now, a new research has described for the first time how this hormone also regulates the number of cells in the root in order to control root growth.

Gibberellin normally acts by signaling the removal of proteins which repress growth, and so promotes root cell production.

The new research shows that mutant plants that do not produce gibberellin are unable to increase their cell production rate and the size of the root meristem, the zone of cell proliferation.

Plants in which the cells in the meristem were made to express a mutant version of the growth-repressing protein GAI not degraded by gibberellin showed disrupted cell proliferation.

Expressing this mutant form, gai, in only one tissue, the endodermis (the innermost layer of the root cortex of a plant), was sufficient to stop the meristem enlarging.

In effect, the rate of expansion of dividing endodermal cells dictates the equivalent rate in other tissues.

According to Professor Malcolm Bennett, Biology Director for the Centre for Plant Integrative Biology and Professor of Plant Sciences in the Division of Plant and Crop Sciences, “We have shown that gibberellin plays a crucial role in controlling the size of the root meristem, and that it is the endodermis which sets the pace for expansion rates in the other tissues.”

“Understanding precisely how hormones regulate plant growth is one of the key areas of fundamental plant biology which will underpin crop improvements in the future,” he said. (ANI)

Ability to imagine oneself in someone else’s shoes ‘tied to empathy’

Washington, June 24 (ANI): The way our brain handles how we move through space-including being able to imagine literally stepping into someone else’s shoes-may be related to how and why we experience empathy toward others, say researchers.

The new study from Vanderbilt University has been published in the online scientific journal PLoS ONE.

Empathy, partly, involves the ability to simulate the internal states of others.

The authors hypothesized that humans’ ability to manipulate, rotate and simulate mental representations of the physical world, including their own bodies, would contribute significantly to their ability to empathize.

“Our language is full of spatial metaphors, particularly when we attempt to explain or understand how other people think or feel. We often talk about putting ourselves in others’ shoes, seeing something from someone else’s point of view, or figuratively looking over someone’s shoulder,” Sohee Park, report co-author and professor of psychology, said.

“Although future work is needed to elucidate the nature of the relationship between empathy, spatial abilities and their potentially overlapping neural underpinnings, this work provides initial evidence that empathy might be, in part, spatially represented,” the expert said.

“We use spatial manipulations of mental representations all the time as we move through the physical world. As a result, we have readily available cognitive resources to deploy in our attempts to understand what we see. This may extend to our understanding of others’ mental states,” Katharine N. Thakkar, a psychology graduate student at Vanderbilt and the report’s lead author, said.

“Separate lines of neuroimaging research have noted involvement of the same brain area, the parietal cortex, during tasks involving visuo-spatial processes and empathy,” she added.

To test their hypothesis that empathy and spatial processes are linked, the researchers designed an experiment in which subjects had to imagine themselves in the position of another person and make a judgment about where this other person’s arm was pointing. The task required the subject to mentally transform their body position to that of the other person.

“We expected that the efficiency with which people could imagine these transformations would be associated with empathy. Because we were interested in linking spatial ability with empathy, we also included a very simple task of spatial attention called the line bisection task.

This test involves looking at a horizontal line and marking the midpoint. Although this task is very simple, it appears to be a powerful way to assess subtle biases in spatial attention,” Thakkar said.

The researchers compared performance on the test with how empathetic the subjects reported themselves to be. They found that higher self-reported empathy was associated with paying more attention to the right side of space.

Boffins also found that in the female subjects only, the more empathetic people rated themselves, the longer they took to imagine themselves in the position of the person on the screen. (ANI)

Ability to imagine oneself in someone else’s shoes ‘tied to empathy’

Washington, June 24 (ANI): The way our brain handles how we move through space-including being able to imagine literally stepping into someone else’s shoes-may be related to how and why we experience empathy toward others, say researchers.

The new study from Vanderbilt University has been published in the online scientific journal PLoS ONE.

Empathy, partly, involves the ability to simulate the internal states of others.

The authors hypothesized that humans’ ability to manipulate, rotate and simulate mental representations of the physical world, including their own bodies, would contribute significantly to their ability to empathize.

“Our language is full of spatial metaphors, particularly when we attempt to explain or understand how other people think or feel. We often talk about putting ourselves in others’ shoes, seeing something from someone else’s point of view, or figuratively looking over someone’s shoulder,” Sohee Park, report co-author and professor of psychology, said.

“Although future work is needed to elucidate the nature of the relationship between empathy, spatial abilities and their potentially overlapping neural underpinnings, this work provides initial evidence that empathy might be, in part, spatially represented,” the expert said.

“We use spatial manipulations of mental representations all the time as we move through the physical world. As a result, we have readily available cognitive resources to deploy in our attempts to understand what we see. This may extend to our understanding of others’ mental states,” Katharine N. Thakkar, a psychology graduate student at Vanderbilt and the report’s lead author, said.

“Separate lines of neuroimaging research have noted involvement of the same brain area, the parietal cortex, during tasks involving visuo-spatial processes and empathy,” she added.

To test their hypothesis that empathy and spatial processes are linked, the researchers designed an experiment in which subjects had to imagine themselves in the position of another person and make a judgment about where this other person’s arm was pointing. The task required the subject to mentally transform their body position to that of the other person.

“We expected that the efficiency with which people could imagine these transformations would be associated with empathy. Because we were interested in linking spatial ability with empathy, we also included a very simple task of spatial attention called the line bisection task.

This test involves looking at a horizontal line and marking the midpoint. Although this task is very simple, it appears to be a powerful way to assess subtle biases in spatial attention,” Thakkar said.

The researchers compared performance on the test with how empathetic the subjects reported themselves to be. They found that higher self-reported empathy was associated with paying more attention to the right side of space.

Boffins also found that in the female subjects only, the more empathetic people rated themselves, the longer they took to imagine themselves in the position of the person on the screen. (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)

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)

‘Creativity chemical’ in the brain biased towards smarter people

London, May 21 (ANI): High levels of a so-called “creativity chemical” in a certain part of the brain is what boosts creativity in smart people, revealed a study.

People with average intelligence, on the other hand, are less ingenious because of low levels of the same chemical.

N-acetyl-aspartate, which is found in neurons, is apparently linked with neural health and metabolism.

Already, Rex Jung at the University of New Mexico in Albuquerque and his colleagues knew that high levels of NAA in the left parieto-occipital lobe, which coordinates sensory and visual information, were linked with intelligence.

In order to know whether NAA also plays a role in creativity, the researchers recruited 56 men and women aged 18 to 39, and measured the NAA levels in various regions of their brains.

The researchers also tested the volunteers’ general intelligence and, more specifically, their capacity for divergent thinking-a factor in creativity that includes coming up with novel ideas, such as new uses for everyday objects.

On the whole, volunteers’ creativity scores were concurrent with levels of NAA in a brain region called the anterior cingulate gyrus (ACG), which regulates the activity of the frontal cortex – implicated in higher mental functions.

However, while low levels of NAA in the ACG correlated with high creativity in people of average intelligence, the reverse was found to be true in people with IQs of above 120.

Jung predicted that if there is less NAA to regulate frontal cortex activity in “average” brains, they are freer to roam and find new ideas.

However, in highly intelligent people, tighter control over the frontal cortex could apparently enhance creativity.

This could be because they are more likely to come up with new ideas anyway, and the tighter control allows them to “fine-tune” that ability.

“People say you have to let your mind wonder freely to be creative. For people of average intelligence, perhaps it’s true that you need to utilise more areas of your [frontal cortex] for something truly novel and creative to emerge, but in more intelligent folks, there’s something different going on,” New Scientist magazine quoted Jung as saying.

In his opinion, the findings could shed new light on what made the brains of creative geniuses like Einstein tick. (ANI)

Ghrelin hormone increases appetite, favours build up of abdominal fat

Washington, May 21 (ANI): In a new study, scientists the University Hospital of Navarra have found that the ghrelin hormone not only increases appetite, but also favours the accumulation of lipids in visceral fatty tissue, located in the abdominal zone and considered to be the most harmful.

Ghrelin is a hormone produced in the stomach and its function is to tell the brain that the body has to be fed. Thus, the level of this secretion increases before eating and decreases after.

However, Amaia Rodríguez Murueta-Goyena, doctor in biology and main researcher of the study, and colleagues discovered that, besides stimulating the hypothalamus to generate appetite, ghrelin also acts on the tabula rasa cortex.

They observed how this hormone favoured the accumulation of lipids in visceral fatty tissue. In concrete, it causes the over-expression of the fatty genes that take part in the retention of lipids, Rodríguez said.

It is precisely this accumulated fat in the region of the abdomen that is deemed to be most harmful, as it is accompanied by comorbilities, visceral obesity being related to higher blood pressure or type 2 diabetes.

Moreover, being located in the abdominal zone and in direct contact with the liver, this type of fatty tissue favours the formation of liver fat and increases the risk of developing resistance to insulin.

The researcher pointed out that normally, on being associated with hypertension, high levels of triglycerides, resistance to insulin and hypercholesterolemia, visceral fat favours the metabolic syndrome.

Rodriguez said that ghrelin can show itself in acylated or deacylated form, the difference being in the octanoic acid present in the composition of the former.

Previously it was thought that only the acylated form was active in the process of weight increase, but many studies point to both hormones being biologically functional.

Researchers pointed out that this discovery of the twin action of ghrelin on the organism opens the door to future treatment for obesity and which, for the time being, is limited to in vitro studies in cell and animal models.

The study was published recently in the International Journal of Obesity. (ANI)

Meditation helps build stronger brains

Washington, May 13 (ANI): A new study has confirmed what many people believed: meditation helps increase gray matter.

A research team from University of California, Los Angeles scanned the brains of people who meditate and found that certain regions in the brains of long-term meditators were larger than in a similar control group.

Meditators showed significantly larger volumes of the hippocampus and areas within the orbito-frontal cortex, the thalamus and the inferior temporal gyrus – all known for regulating emotions.

“We know that people who consistently meditate have a singular ability to cultivate positive emotions, retain emotional stability and engage in mindful behaviour,” said Eileen Luders, lead author and a postdoctoral research fellow at the UCLA Laboratory of Neuro Imaging.

“The observed differences in brain anatomy might give us a clue why meditators have these exceptional abilities,” Luders added.

During the study, the research team looked at 44 people. Half were asked to practice various forms of meditation such as Zazen, Samatha and Vipassana and the other half acted as the control group.

More than half of all the meditators said that deep concentration was an essential part of their practice, and most meditated between 10 and 90 minutes every day.

The brains of the meditators showed larger volumes of the right hippocampus and increased gray matter in the right orbito-frontal cortex, the right thalamus and the left inferior temporal lobe.

Because these areas of the brain are closely linked to emotion, Luders said, “these might be the neuronal underpinnings that give meditators’ the outstanding ability to regulate their emotions and allow for well-adjusted responses to whatever life throws their way.”

The study is published in the journal NeuroImage. (ANI)

Brain mechanism behind confidence while making choices unravelled

Washington, May 8 (ANI): People tend to judge their confidence while making choices several times a day, and now researchers have uncovered the biological mechanisms behind the belief that a choice is likely to be correct.

Many studies have shown that choice certainty is closely associated with reaction time, and with decision accuracy.

The new study tested the possibility that the same brain cell mechanism that underlies decision-making might also underlie judgments about certainty.

“Choice certainty allows us to translate our convictions into suitable actions,” said Dr. Roozbeh Kiani at the University of Washington (UW).
In the study, rhesus monkeys played a video game in which they watched a dynamic, random dot display, while they had to determine the direction of motion.

The difficulty of the task was varied by both the percentage of moving dots and the viewing time. After a short delay, the fixation point faded, which cued the monkey to indicate its choice of direction by moving its eyes toward one of two targets.

The monkey would receive a reward for each correct choice, and no reward for an incorrect choice.

On a random half of the trials, the monkey could pick a third, fixed-position target that guaranteed a small reward, instead of making a choice.

While watching the moving dots, the monkeys didn’t know whether the third option would be offered. The sure bet was shown during the short delay.

“The monkeys opted for the sure target when the chance of making a correct decision about the motion direction was small,” noted the researchers.

They suggested that the monkeys chose the sure bet because of uncertainty, not because that round of the game was too hard.

The researchers recorded activity from 70 brain cells while the monkeys made their decisions, and the cells were located in the lateral intraparietal cortex of the brain, which plays a role in spatial sensations.

In rhesus monkeys, the lateral area of the parietal lobe is attuned to movement.

After analysing detailed data from the study results, the researchers showed that the mechanism underlying certainty in these brain cells is linked with the same evidence accumulation that underlies choice and decision time.

“Some research has suggested that brain cells in an area associated with reward expectation or conflict are associated with decision uncertainty. However, these brain cells presumably receive this information from neurons involved in decision making,” noted Kiani.

The results of this study advance the understanding of brain cell mechanisms that underlie decision making by coupling for the first time the mechanisms that lead to decision formation and the establishment of a degree of confidence in that decision.

The results of the study have been published in the latest edition of Science. (ANI)