The Healthy woman with no Cerebellum

A woman has reached the age of 24 without anyone realising she was missing a large part of her brain. The case highlights just how adaptable the organ is.

The discovery was made when the woman was admitted to the Chinese PLA General Hospital of Jinan Military Area Command in Shandong Province complaining of dizziness and nausea.

She told doctors she'd had problems walking steadily for most of her life, and her mother reported that she hadn't walked until she was 7 and that her speech only became intelligible at the age of 6.

Doctors did a CAT scan and immediately identified the source of the problem – her entire cerebellum was missing (see scan, below left).

The space where it should be was empty of tissue. Instead it was filled with cerebrospinal fluid, which cushions the brain and provides defence against disease.

The cerebellum – sometimes known as the "little brain" – is located underneath the two hemispheres.

It looks different from the rest of the brain because it consists of much smaller and more compact folds of tissue. It represents about 10 per cent of the brain's total volume but contains 50 per cent of its neurons.

Although it is not unheard of to have part of your brain missing, either congenitally or from surgery, the woman joins an elite club of just nine people who are known to have lived without their entire cerebellum.

A detailed description of how the disorder affects a living adult is almost non-existent, say doctors from the Chinese hospital, because most people with the condition die at a young age and the problem is only discovered on autopsy (Brain, doi.org/vh7)

The cerebellum's main job is to control voluntary movements and balance, and it is also thought to be involved in our ability to learn specific motor actions and speak. Problems in the cerebellum can lead to severe mental impairment, movement disorders, epilepsy or a potentially fatal build-up of fluid in the brain.

However, in this woman, the missing cerebellum resulted in only mild to moderate motor deficiency, and mild speech problems such as slightly slurred pronunciation.

Her doctors describe these effects as "less than would be expected", and say her case highlights the remarkable plasticity of the brain.

"These rare cases are interesting to understand how the brain circuitry works and compensates for missing parts," says Mario Manto, who researches cerebellar disorders at the Free University of Brussels in Belgium.

The patient's doctors suggest that normal cerebellar function may have been taken over by the cortex – brain scans should reveal the answer.

AUTISM: Difficulty in Recognising Faces Linked to Performance in a Group of Neurons

Neuroscientists at Georgetown University Medical Center (GUMC) have discovered a brain anomaly that explains why some people diagnosed with autism cannot easily recognize faces -- a deficit linked to the impairments in social interactions considered to be the hallmark of the disorder.

They also say that the novel neuroimaging analysis technique they developed to arrive at this finding is likely to help link behavioral deficits to differences at the neural level in a range of neurological disorders.

The final manuscript published March 15 in the online journal NeuroImage: Clinical, the scientists say that in the brains of many individuals with autism, neurons in the brain area that processes faces (the fusiform face area, or FFA) are too broadly "tuned" to finely discriminate between facial features of different people.

They made this discovery using a form of functional magnetic resonance imaging (fMRI) that scans output from the blueberry-sized FFA, located behind the right ear.

"When your brain is processing faces, you want neurons to respond selectively so that each is picking up a different aspect of individual faces. The neurons need to be finely tuned to understand what is dissimilar from one face to another," says the study's senior investigator, Maximilian Riesenhuber, PhD., an associate professor of neuroscience at GUMC.

"What we found in our 15 adult participants with autism is that in those with more severe behavioral deficits, the neurons are more broadly tuned, so that one face looks more like another, as compared with the fine tuning seen in the FFA of typical adults," he says.

"And we found evidence that reduced selectivity in FFA neurons corresponded to greater behavioral deficits in everyday face recognition in our participants. This makes sense. If your neurons cannot tell different faces apart, it makes it more difficult to tell who is talking to you or understand the facial expressions that are conveyed, which limits social interaction."

Riesenhuber adds that there is huge variation in the ability of individuals diagnosed with autism to discriminate faces, and that some autistic people have no problem with facial recognition.

"But for those that do have this challenge, it can have substantial ramifications -- some researchers believe deficits in face processing are at the root of social dysfunction in autism," he says.

The neural basis for face processing
Neuroscientists have used traditional fMRI studies in the past to probe the neural bases of behavioral differences in people with autism, but these studies have produced conflicting results, says Riesenhuber.

"The fundamental problem with traditional fMRI techniques is that they can tell which parts of the brain become active during face processing, but they are poor at directly measuring neuronal selectivity," he says, "and it is this neuronal selectivity that predicts face processing performance, as shown in our previous studies."

To test their hypothesis that differences in neuronal selectivity in the FFA are foundational to differences in face processing abilities in autism, Riesenhuber and the study's lead author, neuroscientist Xiong Jiang, PhD, developed a novel brain imaging analysis technique, termed local regional heterogeneity, to estimate neuronal selectivity.

Read the full article here

Brain research: Slues to why people think and behave differently

Intersubject variability was quantified at each surface vertex across 23 subjects after correction for underlying intrasubject variability. 

Values below the global mean are shown in cool colours while values above the global mean are shown in warm colours. 

Credit: Neuron, Mueller et al. 

Differences in the physical connections of the brain are at the root of what make people think and behave differently from one another.

Researchers reporting in the February 6 issue of the Cell Press journal Neuron shed new light on the details of this phenomenon, mapping the exact brain regions where individual differences occur.

Their findings reveal that individuals' brain connectivity varies more in areas that relate to integrating information than in areas for initial perception of the world.

"Understanding the normal range of individual variability in the human brain will help us identify and potentially treat regions likely to form abnormal circuitry, as manifested in neuropsychiatric disorders," says senior author Dr. Hesheng Liu, of the Massachusetts General Hospital.

Dr. Liu and his colleagues used an imaging technique called resting-state functional magnetic resonance imaging to examine person-to-person variability of brain connectivity in 23 healthy individuals five times over the course of six months.

Functional connectivity variability is significantly associated with the variability in sulcal depth (A) but not the variability in cortical thickness (B). Intersubject anatomical variability was calculated using intraclass correlation (ICC), with the intrasubject variance properly accounted for. 

Sulcal depth variability showed a significant correlation with functional variability (r = 0.30, p < 0.0001) while cortical thickness variability was uncorrelated with functional variability (r = 0.05, p > 0.05). Credit: Neuron, Mueller et al. 

The researchers discovered that the brain regions devoted to control and attention displayed a greater difference in connectivity across individuals than the regions dedicated to our senses like touch and sight.

When they looked at other published studies, the investigators found that brain regions previously shown to relate to individual differences in cognition and behavior overlap with the regions identified in this study to have high variability among individuals.

The researchers were therefore able to pinpoint the areas of the brain where variable connectivity causes people to think and behave differently from one another.

Higher rates of variability across individuals were also displayed in regions of the brain that have undergone greater expansion during evolution.

"Our findings have potential implications for understanding brain evolution and development," says Dr. Liu.

"This study provides a possible linkage between the diversity of human abilities and evolutionary expansion of specific brain regions," he adds.

More information: Neuron, Mueller et al.: "Individual Variability in Functional Connectivity Architecture of the Human Brain." dx.doi.org/10.1016… .2012.12.028

Chronic stress during pregnancy prevents brain benefits of motherhood

A new study in animals shows that chronic stress during pregnancy prevents brain benefits of motherhood, a finding that researchers suggest could increase understanding of postpartum depression.

Rat mothers showed an increase in brain cell connections in regions associated with learning, memory and mood.

In contrast, the brains of mother rats that were stressed twice a day throughout pregnancy did not show this increase.

The researchers were specifically interested in dendritic spines – hair-like growths on brain cells that are used to exchange information with other neurons.

Previous animal studies conducted by lead author Benedetta Leuner of Ohio State University showed that an increase of dendritic spines in new mothers’ brains was associated with improved cognitive function on a task that requires behavioral flexibility – in essence, enabling more effective multitasking.

The dendritic spines increased by about 20 percent in these brain regions in new mothers, according to her findings.

The stress in this new study negated those brain benefits of motherhood, causing the stressed rats’ brains to match brain characteristics of animals that had no reproductive or maternal experience.

The stressed rats also had less physical interaction with their babies than did unstressed rats, a behaviour observed in human mothers who experience postpartum depression.

“Animal mothers in our research that are unstressed show an increase in the number of connections between neurons. Stressed mothers don’t,” said Leuner, assistant professor of psychology and neuroscience at Ohio State.

“We think that makes the stressed mothers more vulnerable. They don’t have the capacity for brain plasticity that the unstressed mothers do, and somehow that’s contributing to their susceptibility to depression.”


Previous research has suggested that there are a number of risk factors for postpartum depression, including hormone fluctuations, prior history of mental illness and environmental factors such as smoking or low socioeconomic status.

One of the strongest predictors, however, is chronic stress during pregnancy, so Leuner sought to create an animal model that could help explain brain changes linked to postpartum depression.

“It’s devastating not only for the mother, because it affects her well-being, but previous research also has shown that children of depressed mothers have impaired cognitive and social development, may have impaired physical development, and are more likely as adults to have depression or anxiety,” she said.

“A better understanding of postpartum depression is important to help the mother but also to prevent some of the damaging effects that this disorder can have on the child.”

The researchers exposed pregnant rats to stress twice a day by limiting their mobility on some days and on other days placing them in water. For three weeks after the rats gave birth, Leuner and colleagues monitored the rats.

The animals showed classic signs of the effects of stress, including lower than normal weight gain and enlarged adrenal glands, a sign of high stress-hormone production. The mothers stressed during pregnancy also gave birth to smaller pups.

“And they were not very good mothers,” Leuner said. After separation from pups for 30 minutes, unstressed mothers would gather up their babies, put them in the nest and nurse them. Stressed mother rats left the pups scattered around, wandered around the cage and fed the babies less frequently.

The stressed mother rats also exhibited more floating than unstressed rats in a water test; animals that float rather than swim are showing depressive-like symptoms.

“These findings in rats mimic some of the symptoms that are seen in women with postpartum depression,” Leuner said.

An examination of the animals’ brains showed that the rats exposed to chronic stress did not grow the additional dendritic spines in the hippocampus and prefrontal cortex that the unstressed mother rats did.

The stressed rats’ brains more closely resembled the brains of control rats that had never been mothers.

“We don’t yet know what the exact trigger is for the increase in spines in motherhood, but we know that the increase goes away with stress,” Leuner said.

She is continuing the work by investigating whether the beneficial effects of motherhood on cognitive functions are also blocked in mothers who are exposed to pregnancy stress as well as whether hormonal factors play a role.

The Developing Brain: There is no final, optimal state

To reflect the ongoing structural changes in the adolescent and twenty-something brain, many journalists and scientists use words and phrases like “unfinished,” “work in progress,” “under construction” and “half-baked.”

Such language implies that the brain eventually reaches a kind of ideal state when it is “done.” But there is no final, optimal state.

The human brain is not a soufflé that gradually expands over time and finally finishes baking at age 30.

Yes, we can identify and label periods of dramatic development—or windows of heightened plasticity—but that should not eclipse the fact that brain changes throughout life.

Whether we can, at this moment in time, meaningfully link this life stage to neuroscience seems a tenuous proposition at best. By itself, brain biology does not dictate who we are.

The members of any one age group are not reducible to a few distinguishing structural changes in the brain.

Ultimately, the fact that a twenty-something has weaker bridges between various brain regions than someone in their thirties is not hugely important—it’s just one aspect of a far more complex identity.

Short-term memory is based on synchronized brain oscillations

In each of the two brain regions (IPF and V4) brain activity shows strong oscillations in a certain set of frequencies called the theta-band.

Credit: Stefanie Liebe, MPI for Biological Cybernetics

Holding information within one's memory for a short while is a seemingly simple and everyday task.

We use our short-term memory when remembering a new telephone number if there is nothing to write at hand, or to find the beautiful dress inside the store that we were just admiring in the shopping window.

Yet, despite the apparent simplicity of these actions, short-term memory is a complex cognitive act that entails the participation of multiple brain regions.

However, whether and how different brain regions cooperate during memory has remained elusive.

A group of researchers from the Max Planck Institute for Biological Cybernetics in Tübingen, Germany have now come closer to answering this question.

They discovered that oscillations between different brain regions are crucial in visually remembering things over a short period of time.

It has long been known that brain regions in the frontal part of the brain are involved in short-term memory, while processing of visual information occurs primarily at the back of the brain.

However, to successfully remember visual information over a short period of time, these distant regions need to coordinate and integrate information.

To better understand how this occurs, scientists from the Max Planck Institute of Biological Cybernetics in the department of Nikos Logothetis recorded electrical activity both in a visual area and in the frontal part of the brain in monkeys.

The scientists showed the animals identical or different images within short intervals while recording their brain activity. The animals then had to indicate whether the second image was the same as the first one.

The scientists observed that, in each of the two brain regions, brain activity showed strong oscillations in a certain set of frequencies called the theta-band.

Importantly, these oscillations did not occur independently of each other, but synchronized their activity temporarily: "It is as if you have two revolving doors in each of the two areas.

During working memory, they get in sync, thereby allowing information to pass through them much more efficiently than if they were out of sync," explains Stefanie Liebe, the first author of the study, conducted in the team of Gregor Rainer in cooperation with Gregor Hörzer from the Technical University Graz.

The more synchronized the activity was, the better could the animals remember the initial image. Thus, the authors were able to establish a direct relationship between what they observed in the brain and the performance of the animal. 

Our brains get confused when we're anxious

Competing neurons in this part of the brain help us make decisions, such as choosing words. (Credit: Image courtesy of Marie Banich)

A new University of Colorado at Boulder study sheds light on the brain mechanisms that allow us to make choices and ultimately could be helpful in improving treatments for the millions of people who suffer from the effects of anxiety disorders.

In the study, CU-Boulder psychology Professor Yuko Munakata and her research colleagues found that "neural inhibition," a process that occurs when one nerve cell suppresses activity in another, is a critical aspect in our ability to make choices.

"The breakthrough here is that this helps us clarify the question of what is happening in the brain when we make choices, like when we choose our words," Munakata said.

"Understanding more about how we make choices, how the brain is doing this and what the mechanisms are, could allow scientists to develop new treatments for things such as anxiety disorders."

Researchers have long struggled to determine why people with anxiety can be paralyzed when it comes to decision-making involving many potential options.

Munakata believes the reason is that people with anxiety have decreased neural inhibition in their brain, which leads to difficulty making choices.

"A lot of the pieces have been there," she said. "What's new in this work is bringing all of this together to say here's how we can fit all of these pieces of information together in a coherent framework explaining why it's especially hard for people with anxiety to make decisions and why it links to neural inhibitors."

A paper on the findings appeared in the Aug. 30 Proceedings of the National Academy of Sciences.

CU-Boulder professors Tim Curran, Marie Banich and Randall O'Reilly, graduate students Hannah Snyder and Erika Nyhus and undergraduate honors thesis student Natalie Hutchison co-authored the paper.

In the study, they tested the idea that neural inhibition in the brain plays a big role in decision-making by creating a computer model of the brain called a neural network simulation.

"We found that if we increased the amount of inhibition in this simulated brain then our system got much better at making hard choices," said Hannah Snyder, a psychology graduate student who worked with Munakata on the study.

"If we decreased inhibition in the brain, then the simulation had much more trouble making choices."

Through their model they looked at the brain mechanisms involved when we choose words. They then tested the model's predictions on people by asking them to think of the first verb that comes to mind when they are presented with a noun.

Thinking on your feet - Brain Size

Smithsonian researchers report that the brains of tiny spiders are so large that they fill their body cavities and overflow into their legs. 

As part of ongoing research to understand how miniaturization affects brain size and behaviour, researchers measured the central nervous systems of nine species of spiders, from rainforest giants to spiders smaller than the head of a pin.

As the spiders get smaller, their brains get proportionally bigger, filling up more and more of their body cavities.

A whole new meaning for thinking on your feet

SAD: Take your light therapy, and stick it in your ear

Many readers in the Northern Hemisphere are likely already starting to experience seasonal affective disorder, appropriately enough known as SAD.

For those people fortunate enough not to be familiar with it, SAD is a mood disorder that is brought on by the shorter day-length experienced in winter - less sunlight results in gloomier people.

One of the most common treatments involves regular exposure to bright artificial lights, that appear to psychologically serve the same purpose as sunlight.

Now, one might assume that such light therapy would require that people see the light. According to the Finnish designers of the Valkee device, however, light also does the trick if you shine it up your ears.

The invention is based around the assertion that not only are our visual systems photosensitive, but so are our brains themselves.

More specifically, there are apparently 18 sites in our brains, where OPN3 photoreceptor proteins are located. These regions will supposedly react favourably to exposure to light, even when that light is filtered through tissue and bone.

The Valkee itself looks a lot like a personal music player, complete with earbuds. Instead of emitting music, however, these buds contain fiber optic lights.

By turning the device on and sticking the glowing fibers in your ears for about ten minutes a day, it is claimed that your brain will receive enough light to send the SAD packing.

Does it sound like quackery? A great deal of people would certainly say so.

Not among those people, however, would be a group of scientists from Finland's University of Oulu.

In two clinical trials, they had people with severe SAD use the device daily, for 8 to 12 minutes a day.

Afterward, when those people completed a BDI-21 questionnaire (a standard for assessing depression), it was found that 92 percent of the subjects in the first trial had completely recovered.

The information presented by the company is definitely somewhat difficult to sort out, although it appears that the results of the second trial were similarly encouraging.

A placebo group was included in at least one of the trials, to ensure that people weren't feeling better merely because they expected to.

To read more about the Valkee device visit their website

Parasite directly alters brain chemistry

A research group from the University of Leeds has shown that infection by the brain parasite Toxoplasma gondii, found in 10-20 per cent of the UK’s population, directly affects the production of dopamine, a key chemical messenger in the brain.

Their findings are the first to demonstrate that a parasite found in the brain of mammals can affect dopamine levels.

Whilst the work has been carried out with rodents, lead investigator Dr. Glenn McConkey of the University’s Faculty of Biological Sciences, believes that the findings could ultimately shed new light on treating human neurological disorders that are dopamine-related such as schizophrenia, attention deficit hyperactivity disorder, and Parkinson’s disease.

This research may explain how these parasites, remarkably, manipulate rodents’ behaviour for their own advantage. Infected mice and rats lose their innate fear of cats, increasing the chances of being caught and eaten, which enables the parasite to return to its main host to complete its life cycle.

In this study, funded by the Stanley Medical Research Institute and Dunhill Medical Trust, the research team found that the parasite causes production and release of many times the normal amount of dopamine in infected brain cells.

Dopamine is a natural chemical which relays messages in the brain controlling aspects of movement, cognition and behaviour. It helps control the brain’s reward and pleasure centres and regulates emotional responses such as fear. The presence of a certain kind of dopamine receptor is also associated with sensation-seeking, whereas dopamine deficiency in humans results in Parkinson’s disease.

These findings build on earlier studies in which Dr. McConkey’s group found that the parasite actually encodes the enzyme for producing dopamine in its genome.

“Based on these analyses, it was clear that T. gondii can orchestrate a significant increase in dopamine production in neural cells,” says Dr. McConkey.

“Humans are accidental hosts to T. gondii and the parasite could end up anywhere in the brain, so human symptoms of toxoplasmosis infection may depend on where parasite ends up. This may explain the observed statistical link between incidences of schizophrenia and toxoplasmosis infection.”

Dr. McConkey says his next experiments will investigate how the parasite enzyme triggers dopamine production and how this may change behaviour.

First two-way interaction between a primate brain and a virtual body

In a first-ever demonstration of a two-way interaction between a primate brain and a virtual body, two monkeys trained at the Duke University Center for Neuroengineering learned to employ brain activity alone to move an avatar hand and identify the texture of virtual objects.

“Someday in the near future, quadriplegic patients will take advantage of this technology not only to move their arms and hands and to walk again, but also to sense the texture of objects placed in their hands, or experience the nuances of the terrain on which they stroll with the help of a wearable robotic exoskeleton,” said study leader Miguel Nicolelis, MD, PhD, professor of neurobiology at Duke University Medical Center and co-director of the Duke Center for Neuroengineering.

Without moving any part of their real bodies, the monkeys used their electrical brain activity to direct the virtual hands of an avatar to the surface of virtual objects and, upon contact, were able to differentiate their textures.

Although the virtual objects employed in this study were visually identical, they were designed to have different artificial textures that could only be detected if the animals explored them with virtual hands controlled directly by their brain’s electrical activity.

The texture of the virtual objects was expressed as a pattern of minute electrical signals transmitted to the monkeys’ brains. Three different electrical patterns corresponded to each of three different object textures.

Because no part of the animal’s real body was involved in the operation of this brain-machine-brain interface, these experiments suggest that in the future patients severely paralyzed due to a spinal cord lesion may take advantage of this technology, not only to regain mobility, but also to have their sense of touch restored, said Nicolelis, who was senior author of the study published in the journal Nature on October 5, 2011.

“This is the first demonstration of a brain-machine-brain interface (BMBI) that establishes a direct, bidirectional link between a brain and a virtual body,” Nicolelis said

“In this BMBI, the virtual body is controlled directly by the animal’s brain activity, while its virtual hand generates tactile feedback information that is signaled via direct electrical microstimulation of another region of the animal’s cortex.”

“We hope that in the next few years this technology could help to restore a more autonomous life to many patients who are currently locked in without being able to move or experience any tactile sensation of the surrounding world,” Nicolelis said.

“This is also the first time we’ve observed a brain controlling a virtual arm that explores objects while the brain simultaneously receives electrical feedback signals that describe the fine texture of objects ‘touched’ by the monkey’s newly acquired virtual hand,” Nicolelis said.

Read more of this article here

South African fossils: Between ape and human

Two fossil skeletons of early humans appear to mark a halfway stage between primitive "ape-men" and our direct ancestors.

A year of detailed study has revealed that the skeletons are a hodgepodge of anatomical features: some bones look almost human while others are chimpanzee-like.

The two fossils, an adult female and a juvenile male, were discovered in the Malapa cave system near Johannesburg, South Africa, in 2008.

Both about 1.2 metres tall, they are unusually complete and well-preserved and date from 1,977,000 years ago.

Excavated by Lee Berger of the University of the Witwatersrand in Johannesburg, and colleagues, they were given the name Australopithecus sediba.

Australopithecines were early hominids that lived between 4 and 2 million years ago: the best-known fossil example is a 3.2-million-year-old Australopithecus afarensis skeleton found in Ethiopia and nicknamed Lucy. Unlike chimpanzees and other apes, they walked on two legs, but their brains were still small. Not until Homo erectus evolved, around 1.8 million years ago, did larger brains appear.

Together with a large team of researchers, Berger has spent the last year intensively studying the two A. sediba skeletons. He says they are unusually advanced for an Australopithecus, and may show how the australopiths evolved into humans.
Brainy

One area of particular interest is the brain size. So far, the male skull has been excavated. It's also been named: South African schoolchildren chose the name Karabo, which means "answer" in the Setswana and Sotho languages of southern Africa.

Kristian Carlson of the University of the Witwatersrand and colleagues used synchrotron scans to build a detailed 3D image of the inside of the skull, allowing them to calculate the shape of Karabo's brain.

This was small even for an australopith, with a volume of just 420 cubic centimetres. A. afarensis, by contrast, averaged 459 cc, despite being an earlier species. That suggests there was no overall increase in brain size over the course of australopith evolution.

But Carlson says A. sediba's brain had been subtly reorganised. The orbitofrontal region, which sits just behind the eyes, is a different shape to those of other australopiths and apes, and may have been rewired into a more human-like design.

Carlson draws particular attention to an area called the inferior frontal gyrus, which has bulged out in A. sediba. In modern humans this area is important for language processing, hinting that A. sediba had advanced communication skills.

Carlson remains cautious, however, pointing out that spoken language relies on adaptations like vocal cords. Although neck bones were part of the find, they have not yet been studied in detail, so we don't know if A. sediba was built for speech.

We need to treat the brain studies with great caution, says Robert Barton of Durham University in the UK. "Interpretation of surface features of brains is fraught at the best of times," he says, "but on individual specimens that are merely impressions of the original brain and millions of years old to boot?"

Scientists find they can control how people react to group pressure

Researchers found they were able to control whether volunteers conformed to social pressure by using powerful electromagnetic pulses that changed the activity of a small part of the brain.

Volunteers whose posterior medial frontal cortex, an area in the middle of the brain that is associated with reward processing, were exposed to the magnetic pulses suffered reduced levels of conformity.

The researchers believe this part of the brain dates back a long way in the evolution of animals and is responsible or automatically "correcting" our performance when we fall out of line with a group.

They say that by suspending this mechanism, it allows people to think and behave differently. They now believe it may be possible to develop drugs or behaviour changing techniques that could increase or decrease people's conformity.

Dr Vasily Klucharev, a neuroscientist who led the research at the Radboud University Nijmegen, in Holland, said: "People can try to reduce conformity in certain situations, especially when they know about negative consequences of group pressure such as criminal behaviour, propaganda or aggressive marketing.

"Right now we can search for behavioural techniques that modulate activity of the posterior medial frontal cortex without any physical intervention. Hopefully, with help of these techniques someone would be able to partly immune themselves to 'group pressure'.

"Drug manipulation of dopamine could also affect conformity."

Such drugs would be controversial, however, as they could be used by companies hoping to make their employees more reliable or to help control rebellious individuals.

In the study, the researchers asked 49 female volunteers to take part in a study where they were asked to rate the attractiveness of 220 photographs of female faces, but they were allowed to change their ratings after seeing what others in the study had scored.

When Transcranial Electromagnetic Stimulation (TMS) was used to inhibit the activity of the neurons in the posterior medial frontal cortex, the participants did not change their ratings of the photographs so they were more in line with the rest of the group.

Dr Klucharev believes this part of the brain is responsible for generating an "error" signal when individuals deviate from the group opinion, triggering a cascade that leads them to conform with the group view.

He said: "What if that mechanism could be suspended for a time? The group who were exposed to the TMS changed their views to a much lesser extent – they were immune to 'group pressure'.

"Individuals differ in the strength of the error signal – which is why some people are more conformist than others. It also tells us that conformity is a rather automatic process that is based on an old evolutionary mechanism."

Speaking and Understanding Speech Share the Same Parts of the Brain

The brain has two big tasks related to speech: making it and understanding it.

Psychologists and others who study the brain have debated whether these are really two separate tasks or whether they both use the same regions of the brain.

Now, a new study, published in the August issue of Psychological Science, a journal of the Association for Psychological Science, finds that speaking and understanding speech share the same parts of the brain, with one difference: we don't need the brain regions that control the movements of lips, teeth, and so on to understand speech.

Most studies of how speech works in the brain focuses on comprehension. That's mostly because it's easier to image the brains of people who are listening quietly; talking makes the head move, which is a problem when you're measuring the brain.

But now, the Donders Institute at the Radboud University Nijmegen, where the study was conducted, has developed technology that allows recording from a moving brain.

Laura Menenti, a Postdoctoral Research Associate at the University of Glasgow, co-wrote the paper along with Peter Hagoort of Radboud University Nijmegen and the Max Planck Institute for Psycholinguistics, Sarah Gierhan and Katrien Segaert.

Menenti was initially interested in how the brain produces grammatical sentences and wanted to track the process of producing a sentence in its entirety; looking not only at its grammatical structure but also at its meaning.

"What made this particularly exciting to us was that no one had managed to perform such a study before, meaning that we could explore an almost completely new topic," says Menenti.

The authors used functional MRI technology to measure brain activity in people who were either listening to sentences or speaking sentences.

The other problem with measuring brain activity in people who are speaking is that you have to get them to say the right kind of sentence.

The authors accomplished this with a picture of an action -- a man strangling a woman, say -- with one person coloured green and one coloured red to indicate their order in the sentence.

This prompted people to say either "The man is strangling the woman" or "The woman is strangled by the man." (The experiments were all carried out in Dutch.)

From this, the researchers were able to tell where in the brain three different speech tasks (computing meaning, coming up with the words, and building a grammatical sentence) -- were taking place.

They found that the same areas were activated for each of these tasks in people who were speaking and people who were listening to sentences.

However, although some studies have suggested that while people are listening to speech, they silently articulate the words in order to understand them, the authors found no involvement of motor regions when people were listening.

According to Menenti, though the study was largely designed to answer a specific theoretical question, it also points towards some useful avenues for treatment of people with language-related problems.

It suggests that while it sometimes seems that people with comprehension problems may have intact production, and vice versa, this may not necessarily be the case. According to Menenti, "Our data suggest that these problems would be expected to always at least partly coincide.

On the other, our data confirm the idea that many different processes in the language system, such as understanding meaning or grammar, can at least partly, be damaged independently of each other."

TMS Transcranial Magnetic Stimulation of Brain

Anyone who remembers high-school physics knows that a fluctuating magnetic field can induce an electrical current. That's the principle behind transcranial magnetic stimulation (TMS), where an electromagnet is held over the head and pulsed rapidly. Depending on the frequency of the pulses, this can either enhance or suppress activity in neurons a few centimetres under the skull.

TMS is seen as one of the safer forms of brain stimulation, as it requires no surgery. Yet it is not completely risk free: some people experience pain in the scalp, headaches or facial spasms. More concerning were the 10 cases of seizures triggered by TMS in the first few years of its use.

Fortunately these became very rare once those administering TMS learned to limit the intensity and frequency of the stimulation and give patients regular breaks in treatment. TMS was leapt on as the perfect research tool. Much knowledge of the brain has come from people who have had a stroke or head injury - the mental abilities they lack reveal the role of the damaged area. TMS allows researchers to disable parts of the brain at will in a way that is completely reversible.

The method has also been tried out in numerous medical conditions and forms of enhancement. But many of the studies are regarded sceptically, because it is hard to control for the placebo effect. Researchers have typically tried to give half the volunteers fake therapy with the TMS machine turned off, but people often know if they are getting real treatment or not by the presence or absence of the characteristic physical signs.

TMS has now been approved in the US for treating severe depression. The downside is that patients need to go to a hospital to receive TMS for about 35 minutes a day, five days a week, for four to six weeks. "There's a big schlepp factor," admits Mark George, a neuropsychiatrist at the Medical University of South Carolina.

Last year, however, a group at Emory University in Atlanta found that a month's worth of treatment could be crammed into a few days with no apparent ill effects (Depression and Anxiety, vol 27, p 960). That approach might lead to wider use.

Language and Your Brain - Infographics

For centuries, researchers have studied the brain to find exactly where mechanisms for producing and interpreting language reside. Theories abound on how humans acquire new languages and how our developing brains learn to process languages. We take a look at the mysteries of language and the brain in the infographic below.

Click on the picture to see the whole Infographics on VOXY Blog

Learning Difficulties: Exposure to Pesticides in Womb

Babies exposed to high levels of pesticides while in the womb may suffer from learning problems, a new study suggests.

The study focused on a chemical called permethrin, one of the pyrethroid pesticides, commonly used in agriculture and to kill termites, fleas and household bugs, says lead author Megan Horton of the Columbia Center for Children's Environmental Health. 

Most of the pregnant women in this New York-based study were exposed by spraying for cockroaches.

Permethrin — among the most commonly detected pesticides in homes — is being used more often today as older organophosphorous pesticides are phased out because of concerns that they harm brain development, says Horton, whose study is being published today in Pediatrics.

Researchers measured 348 pregnant women's exposures by asking them to wear backpack air monitors, Horton says. Researchers followed the women and their children for three years.

Children exposed to the highest pesticide levels before birth were three times as likely to have a mental delay compared to children with lower levels, the study says. 

Children with the highest prenatal exposures also scored about 4 points lower on an intelligence test, the Bayley Mental Developmental Index. That test has a mean score of 100, with most people's scores falling within 15 points of that range.

That's about the same intelligence loss caused by lead, says Philip Landrigan, a pediatrics professor and environmental health expert at New York's Mount Sinai School of Medicine.

Pyrethroid pesticides kill bugs by "being toxic to the developing brain," Landrigan says. The results are "very believable and should be taken seriously," Landrigan says.

Because the study is the first to link permethrin with brain damage, researchers need to conduct additional studies before concluding that the pesticide really harms the brain, says Mary Fox, an assistant professor at John Hopkins' Bloomberg School of Public Health.

Even without definitive data, however, Fox says it makes sense for pregnant women to reduce their exposure to bug sprays and other pesticides.

To control bugs, for example, she suggests fixing water leaks, keeping food tightly covered and, if necessary, spraying outside instead of inside the home.

PTSD: Woman who cannot feel fear

A Red Knee'd Tarantula

A woman who cannot feel afraid because of a missing structure in her brain could help scientists discover treatments for post-traumatic stress disorder (PTSD).

Research published in Current Biology showed the woman felt no fear in a variety of scary situations.

These included exposure to snakes and spiders, horror films and a "haunted house". The woman feels other emotions but said as an adult, she had never felt afraid. She is the first known case of someone who is unable to process fear.

Researchers at the University of Iowa said her inability to feel frightened was because she is missing a structure in her brain called the amygdala.

The structure has long been associated with emotional learning - experiments in animals have shown that removing it makes them fearless. However, it has never been observed in a human before.

The woman experienced fear as a child and knows that some situations should be frightening. As an adult she has been in various frightening situations, including being threatened with a knife and held at gunpoint.

Researchers at the University of Iowa, in Iowa City, observed and recorded the woman's responses in situations that would make most people feel fear.

She watched a series of horror films, went to a reputedly haunted house and to an exotic pet store - where she handled dangerous snakes and asked to handle a tarantula.

She showed no fear in any of the situations and had to be prevented from touching the tarantula because of the high risk of being bitten.

When asked why she wanted to touch something that she knows is dangerous, she replied that she was overcome with curiosity.

Lead researcher Justin Feinstein said: "Because she is missing her amygdala, she is also missing the ability to detect and avoid danger in the world. "It is quite remarkable that she is still alive."

Mind-Blowing Brain Images From Then and Now | Wired Science

It is not an accident. There is a grand tradition of scientists making art out of human anatomy, from the comic grotesqueries of Vesalius to the exquisite drawings of Cajal. The twenty-first century is no exception.

Just because these images depend on expensive machines doesn't mean the scientist has become a passive observer, or no longer thinks about the aesthetics.

Keats knew that truth exists in a tangled relationship with beauty, and nothing illustrates that poetic concept better than these scientific images. Their empirical power is entwined with their visual majesty.

More pictures and their stories from Wired Science

Deceivers have less grey matter

A study appearing in the British Journal of Psychiatry documents evidence of structural brain abnormalities in people who habitually lie, cheat and manipulate others.

The researchers, from the University of Southern California, built on previous research that showed there is heightened activity in the prefrontal cortex - the area of the brain that enables most people to feel remorse or learn moral behaviour - when normal people lie.

The new study provides evidence of structural differences in that area among pathological liars.

The subjects for the study were taken from a Los Angeles' temporary employment pool. The researchers conducted a series of psychological tests and interviews that categorized the subjects according to their propensity for mistruth.

"We looked for things like inconsistencies in their stories about occupation, education, crimes and family background," said Adrian Raine, co-author of the study. After categorisation, Raine and co-researcher Yaling Yang used Magnetic Resonance Imaging (MRI) to explore structural brain differences between the groups.

What the researchers found was that the liars had significantly more "white matter" - the wiring in the brain - and slightly less "gray matter", than the truthful subjects. The researchers explained that white matter is the "networking" tissue that holds together and links the grey matter.

Apparently, pathological liars have a surplus of white matter and a deficit of gray matter, meaning they have more tools to lie, coupled with fewer moral restraints. When compared to the normal control subjects, liars had a 22 percent increase in white matter and a 14 percent decrease in prefrontal gray matter.