Arquivo da tag: Cérebro

Why did humans evolve such large brains? Because smarter people have more friends (The Conversation)

June 19, 2017 10.01am EDT

Humans are the only ultrasocial creature on the planet. We have outcompeted, interbred or even killed off all other hominin species. We cohabit in cities of tens of millions of people and, despite what the media tell us, violence between individuals is extremely rare. This is because we have an extremely large, flexible and complex “social brain”.

To truly understand how the brain maintains our human intellect, we would need to know about the state of all 86 billion neurons and their 100 trillion interconnections, as well as the varying strengths with which they are connected, and the state of more than 1,000 proteins that exist at each connection point. Neurobiologist Steven Rose suggests that even this is not enough – we would still need know how these connections have evolved over a person’s lifetime and even the social context in which they had occurred. It may take centuries just to figure out basic neuronal connectivity.

Many people assume that our brain operates like a powerful computer. But Robert Epstein, a psychologist at the American Institute for Behavioural Research and Technology, says this is just shoddy thinking and is holding back our understanding of the human brain. Because, while humans start with senses, reflexes and learning mechanisms, we are not born with any of the information, rules, algorithms or other key design elements that allow computers to behave somewhat intelligently. For instance, computers store exact copies of data that persist for long periods of time, even when the power is switched off. Our brains, meanwhile, are capable of creating false data or false memories, and they only maintain our intellect as long as we remain alive.

We are organisms, not computers

Of course, we can see many advantages in having a large brain. In my recent book on human evolution I suggest it firstly allows humans to exist in a group size of about 150. This builds resilience to environmental changes by increasing and diversifying food production and sharing.

 

As our ancestors got smarter, they became capable of living in larger and larger groups. Mark Maslin, Author provided

A social brain also allows specialisation of skills so individuals can concentrate on supporting childbirth, tool-making, fire setting, hunting or resource allocation. Humans have no natural weapons, but working in large groups and having tools allowed us to become the apex predator, hunting animals as large as mammoths to extinction.

Our social groups are large and complex, but this creates high stress levels for individuals because the rewards in terms of food, safety and reproduction are so great. Hence, Oxford anthropologist Robin Dunbar argues our huge brain is primarily developed to keep track of rapidly changing relationships. It takes a huge amount of cognitive ability to exist in large social groups, and if you fall out of the group you lose access to food and mates and are unlikely to reproduce and pass on your genes.

 

Great. But what about your soap opera knowledge? ronstik / shutterstock

My undergraduates come to university thinking they are extremely smart as they can do differential equations and understand the use of split infinitives. But I point out to them that almost anyone walking down the street has the capacity to hold the moral and ethical dilemmas of at least five soap operas in their head at any one time. And that is what being smart really means. It is the detailed knowledge of society and the need to track and control the ever changing relationship between people around us that has created our huge complex brain.

It seems our brains could be even more flexible that we previously thought. Recent genetic evidence suggests the modern human brain is more malleable and is modelled more by the surrounding environment than that of chimpanzees. The anatomy of the chimpanzee brain is strongly controlled by their genes, whereas the modern human brain is extensively shaped by the environment, no matter what the genetics.

This means the human brain is pre-programmed to be extremely flexible; its cerebral organisation is adjusted by the environment and society in which it is raised. So each new generation’s brain structure can adapt to the new environmental and social challenges without the need to physically evolve.

 

Evolution at work. OtmarW / shutterstock

This may also explain why we all complain that we do not understand the next generation as their brains are wired differently, having grown up in a different physical and social environment. An example of this is the ease with which the latest generation interacts with technology almost if they had co-evolved with it.

So next time you turn on a computer just remember how big and complex your brain is – to keep a track of your friends and enemies.

Anúncios

How the brain leads us to believe we have sharp vision (Science Daily)

Date: October 17, 2014

Source: Bielefeld University

Summary: We assume that we can see the world around us in sharp detail. In fact, our eyes can only process a fraction of our surroundings precisely. In a series of experiments, psychologists have been investigating how the brain fools us into believing that we see in sharp detail.

The thumbnail at the end of an outstretched arm: This is the area that the eye actually can see in sharp detail. Researchers have investigated why the rest of the world also appears to be uniformly detailed. Credit: Bielefeld University

We assume that we can see the world around us in sharp detail. In fact, our eyes can only process a fraction of our surroundings precisely. In a series of experiments, psychologists at Bielefeld University have been investigating how the brain fools us into believing that we see in sharp detail. The results have been published in the scientific magazine Journal of Experimental Psychology: General. Its central finding is that our nervous system uses past visual experiences to predict how blurred objects would look in sharp detail.

“In our study we are dealing with the question of why we believe that we see the world uniformly detailed,” says Dr. Arvid Herwig from the Neuro-Cognitive Psychology research group of the Faculty of Psychology and Sports Science. The group is also affiliated to the Cluster of Excellence Cognitive Interaction Technology (CITEC) of Bielefeld University and is led by Professor Dr. Werner X. Schneider.

Only the fovea, the central area of the retina, can process objects precisely. We should therefore only be able to see a small area of our environment in sharp detail. This area is about the size of a thumb nail at the end of an outstretched arm. In contrast, all visual impressions which occur outside the fovea on the retina become progressively coarse. Nevertheless, we commonly have the impression that we see large parts of our environment in sharp detail.

Herwig and Schneider have been getting to the bottom of this phenomenon with a series of experiments. Their approach presumes that people learn through countless eye movements over a lifetime to connect the coarse impressions of objects outside the fovea to the detailed visual impressions after the eye has moved to the object of interest. For example, the coarse visual impression of a football (blurred image of a football) is connected to the detailed visual impression after the eye has moved. If a person sees a football out of the corner of her eye, her brain will compare this current blurred picture with memorised images of blurred objects. If the brain finds an image that fits, it will replace the coarse image with a precise image from memory. This blurred visual impression is replaced before the eye moves. The person thus thinks that she already sees the ball clearly, although this is not the case.

The psychologists have been using eye-tracking experiments to test their approach. Using the eye-tracking technique, eye movements are measured accurately with a specific camera which records 1000 images per second. In their experiments, the scientists have recorded fast balistic eye movements (saccades) of test persons. Though most of the participants did not realise it, certain objects were changed during eye movement. The aim was that the test persons learn new connections between visual stimuli from inside and outside the fovea, in other words from detailed and coarse impressions. Afterwards, the participants were asked to judge visual characteristics of objects outside the area of the fovea. The result showed that the connection between a coarse and detailed visual impression occurred after just a few minutes. The coarse visual impressions became similar to the newly learnt detailed visual impressions.

“The experiments show that our perception depends in large measure on stored visual experiences in our memory,” says Arvid Herwig. According to Herwig and Schneider, these experiences serve to predict the effect of future actions (“What would the world look like after a further eye movement”). In other words: “We do not see the actual world, but our predictions.”


Journal Reference:

  1. Arvid Herwig, Werner X. Schneider. Predicting object features across saccades: Evidence from object recognition and visual search. Journal of Experimental Psychology: General, 2014; 143 (5): 1903 DOI: 10.1037/a0036781

Scientists find ‘hidden brain signatures’ of consciousness in vegetative state patients (Science Daily)

Date: October 16, 2014

Source: University of Cambridge

Summary: Scientists in Cambridge have found hidden signatures in the brains of people in a vegetative state, which point to networks that could support consciousness even when a patient appears to be unconscious and unresponsive. The study could help doctors identify patients who are aware despite being unable to communicate.

These images show brain networks in two behaviorally similar vegetative patients (left and middle), but one of whom imagined playing tennis (middle panel), alongside a healthy adult (right panel). Credit: Srivas Chennu

Scientists in Cambridge have found hidden signatures in the brains of people in a vegetative state, which point to networks that could support consciousness even when a patient appears to be unconscious and unresponsive. The study could help doctors identify patients who are aware despite being unable to communicate.

There has been a great deal of interest recently in how much patients in a vegetative state following severe brain injury are aware of their surroundings. Although unable to move and respond, some of these patients are able to carry out tasks such as imagining playing a game of tennis. Using a functional magnetic resonance imaging (fMRI) scanner, which measures brain activity, researchers have previously been able to record activity in the pre-motor cortex, the part of the brain which deals with movement, in apparently unconscious patients asked to imagine playing tennis.

Now, a team of researchers led by scientists at the University of Cambridge and the MRC Cognition and Brain Sciences Unit, Cambridge, have used high-density electroencephalographs (EEG) and a branch of mathematics known as ‘graph theory’ to study networks of activity in the brains of 32 patients diagnosed as vegetative and minimally conscious and compare them to healthy adults. The findings of the research are published today in the journal PLOS Computational Biology. The study was funded mainly by the Wellcome Trust, the National Institute of Health Research Cambridge Biomedical Research Centre and the Medical Research Council (MRC).

The researchers showed that the rich and diversely connected networks that support awareness in the healthy brain are typically — but importantly, not always — impaired in patients in a vegetative state. Some vegetative patients had well-preserved brain networks that look similar to those of healthy adults — these patients were those who had shown signs of hidden awareness by following commands such as imagining playing tennis.

Dr Srivas Chennu from the Department of Clinical Neurosciences at the University of Cambridge says: “Understanding how consciousness arises from the interactions between networks of brain regions is an elusive but fascinating scientific question. But for patients diagnosed as vegetative and minimally conscious, and their families, this is far more than just an academic question — it takes on a very real significance. Our research could improve clinical assessment and help identify patients who might be covertly aware despite being uncommunicative.”

The findings could help researchers develop a relatively simple way of identifying which patients might be aware whilst in a vegetative state. Unlike the ‘tennis test’, which can be a difficult task for patients and requires expensive and often unavailable fMRI scanners, this new technique uses EEG and could therefore be administered at a patient’s bedside. However, the tennis test is stronger evidence that the patient is indeed conscious, to the extent that they can follow commands using their thoughts. The researchers believe that a combination of such tests could help improve accuracy in the prognosis for a patient.

Dr Tristan Bekinschtein from the MRC Cognition and Brain Sciences Unit and the Department of Psychology, University of Cambridge, adds: “Although there are limitations to how predictive our test would be used in isolation, combined with other tests it could help in the clinical assessment of patients. If a patient’s ‘awareness’ networks are intact, then we know that they are likely to be aware of what is going on around them. But unfortunately, they also suggest that vegetative patients with severely impaired networks at rest are unlikely to show any signs of consciousness.”


Journal Reference:

  1. Chennu S, Finoia P, Kamau E, Allanson J, Williams GB, et al. Spectral Signatures of Reorganised Brain Networks in Disorders of Consciousness. PLOS Computational Biology, 2014; 10 (10): e1003887 DOI:10.1371/journal.pcbi.1003887

Clouds in the Head: New Model of Brain’s Thought Processes (Science Daily)

May 21, 2013 — A new model of the brain’s thought processes explains the apparently chaotic activity patterns of individual neurons. They do not correspond to a simple stimulus/response linkage, but arise from the networking of different neural circuits. Scientists funded by the Swiss National Science Foundation (SNSF) propose that the field of brain research should expand its focus.

A new model of the brain’s thought processes explains the apparently chaotic activity patterns of individual neurons. They do not correspond to a simple stimulus/response linkage, but arise from the networking of different neural circuits. (Credit: iStockphoto/Sebastian Kaulitzki)

Many brain researchers cannot see the forest for the trees. When they use electrodes to record the activity patterns of individual neurons, the patterns often appear chaotic and difficult to interpret. “But when you zoom out from looking at individual cells, and observe a large number of neurons instead, their global activity is very informative,” says Mattia Rigotti, a scientist at Columbia University and New York University who is supported by the SNSF and the Janggen-Pöhn-Stiftung. Publishing inNature together with colleagues from the United States, he has shown that these difficult-to-interpret patterns in particular are especially important for complex brain functions.

What goes on in the heads of apes

The researchers have focussed their attention on the activity patterns of 237 neurons that had been recorded some years previously using electrodes implanted in the frontal lobes of two rhesus monkeys. At that time, the apes had been taught to recognise images of different objects on a screen. Around one third of the observed neurons demonstrated activity that Rigotti describes as “mixed selectivity.” A mixed selective neuron does not always respond to the same stimulus (the flowers or the sailing boat on the screen) in the same way. Rather, its response differs as it also takes account of the activity of other neurons. The cell adapts its response according to what else is going on in the ape’s brain.

Chaotic patterns revealed in context

Just as individual computers are networked to create concentrated processing and storage capacity in the field of Cloud Computing, links in the complex cognitive processes that take place in the prefrontal cortex play a key role. The greater the density of the network in the brain, in other words the greater the proportion of mixed selectivity in the activity patterns of the neurons, the better the apes were able to recall the images on the screen, as demonstrated by Rigotti in his analysis. Given that the brain and cognitive capabilities of rhesus monkeys are similar to those of humans, mixed selective neurons should also be important in our own brains. For him this is reason enough why brain research from now on should no longer be satisfied with just the simple activity patterns, but should also consider the apparently chaotic patterns that can only be revealed in context.

Journal Reference:

  1. Mattia Rigotti, Omri Barak, Melissa R. Warden, Xiao-Jing Wang, Nathaniel D. Daw, Earl K. Miller, Stefano Fusi. The importance of mixed selectivity in complex cognitive tasksNature, 2013; DOI: 10.1038/nature12160

Mind Over Matter? Core Body Temperature Controlled by the Brain (Science Daily)

Apr. 8, 2013 — A team of researchers led by Associate Professor Maria Kozhevnikov from the Department of Psychology at the National University of Singapore (NUS) Faculty of Arts and Social Sciences showed, for the first time, that it is possible for core body temperature to be controlled by the brain. The scientists found that core body temperature increases can be achieved using certain meditation techniques (g-tummo) which could help in boosting immunity to fight infectious diseases or immunodeficiency.

Meditation. (Credit: © Yuri Arcurs / Fotolia)

Published in science journal PLOS ONE in March 2013, the study documented reliable core body temperature increases for the first time in Tibetan nuns practising g-tummo meditation. Previous studies on g-tummo meditators showed only increases in peripheral body temperature in the fingers and toes. The g-tummo meditative practice controls “inner energy” and is considered by Tibetan practitioners as one of the most sacred spiritual practices in the region. Monasteries maintaining g-tummo traditions are very rare and are mostly located in the remote areas of eastern Tibet.

The researchers collected data during the unique ceremony in Tibet, where nuns were able to raise their core body temperature and dry up wet sheets wrapped around their bodies in the cold Himalayan weather (-25 degree Celsius) while meditating. Using electroencephalography (EEG) recordings and temperature measures, the team observed increases in core body temperature up to 38.3 degree Celsius. A second study was conducted with Western participants who used a breathing technique of the g-tummo meditative practice and they were also able to increase their core body temperature, within limits.

Applications of the research findings

The findings from the study showed that specific aspects of the meditation techniques can be used by non-meditators to regulate their body temperature through breathing and mental imagery. The techniques could potentially allow practitioners to adapt to and function in cold environments, improve resistance to infections, boost cognitive performance by speeding up response time and reduce performance problems associated with decreased body temperature.

The two aspects of g-tummo meditation that lead to temperature increases are “vase breath” and concentrative visualisation. “Vase breath” is a specific breathing technique which causes thermogenesis, which is a process of heat production. The other technique, concentrative visualisation, involves focusing on a mental imagery of flames along the spinal cord in order to prevent heat losses. Both techniques work in conjunction leading to elevated temperatures up to the moderate fever zone.

Assoc Prof Kozhevnikov explained, “Practicing vase breathing alone is a safe technique to regulate core body temperature in a normal range. The participants whom I taught this technique to were able to elevate their body temperature, within limits, and reported feeling more energised and focused. With further research, non-Tibetan meditators could use vase breathing to improve their health and regulate cognitive performance.”

Further research into controlling body temperature

Assoc Prof Kozhevnikov will continue to explore the effects of guided imagery on neurocognitive and physiological aspects. She is currently training a group of people to regulate their body temperature using vase breathing, which has potential applications in the field of medicine. Furthermore, the use of guided mental imagery in conjunction with vase breathing may lead to higher body temperature increases and better health.

Journal Reference:

  1. Maria Kozhevnikov, James Elliott, Jennifer Shephard, Klaus Gramann. Neurocognitive and Somatic Components of Temperature Increases during g-Tummo Meditation: Legend and RealityPLoS ONE, 2013; 8 (3): e58244 DOI:10.1371/journal.pone.0058244

Red Brain, Blue Brain: Republicans and Democrats Process Risk Differently, Research Finds (Science Daily)

Feb. 13, 2013 — A team of political scientists and neuroscientists has shown that liberals and conservatives use different parts of the brain when they make risky decisions, and these regions can be used to predict which political party a person prefers. The new study suggests that while genetics or parental influence may play a significant role, being a Republican or Democrat changes how the brain functions.

Republicans and Democrats differ in the neural mechanisms activated while performing a risk-taking task. Republicans more strongly activate their right amygdala, associated with orienting attention to external cues. Democrats have higher activity in their left posterior insula, associated with perceptions of internal physiological states. This activation also borders the temporal-parietal junction, and therefore may reflect a difference in internal physiological drive as well as the perception of the internal state and drive of others. (Credit: From: Darren Schreiber, Greg Fonzo, Alan N. Simmons, Christopher T. Dawes, Taru Flagan, James H. Fowler, Martin P. Paulus. Red Brain, Blue Brain: Evaluative Processes Differ in Democrats and Republicans. PLoS ONE, 2013; 8 (2): e52970 DOI: 10.1371/journal.pone.0052970)

Dr. Darren Schreiber, a researcher in neuropolitics at the University of Exeter, has been working in collaboration with colleagues at the University of California, San Diego on research that explores the differences in the way the brain functions in American liberals and conservatives. The findings are published Feb. 13 in the journalPLOS ONE.

In a prior experiment, participants had their brain activity measured as they played a simple gambling game. Dr. Schreiber and his UC San Diego collaborators were able to look up the political party registration of the participants in public records. Using this new analysis of 82 people who performed the gambling task, the academics showed that Republicans and Democrats do not differ in the risks they take. However, there were striking differences in the participants’ brain activity during the risk-taking task.

Democrats showed significantly greater activity in the left insula, a region associated with social and self-awareness. Meanwhile Republicans showed significantly greater activity in the right amygdala, a region involved in the body’s fight-or-flight system. These results suggest that liberals and conservatives engage different cognitive processes when they think about risk.

In fact, brain activity in these two regions alone can be used to predict whether a person is a Democrat or Republican with 82.9% accuracy. By comparison, the longstanding traditional model in political science, which uses the party affiliation of a person’s mother and father to predict the child’s affiliation, is only accurate about 69.5% of the time. And another model based on the differences in brain structure distinguishes liberals from conservatives with only 71.6% accuracy.

The model also outperforms models based on differences in genes. Dr. Schreiber said: “Although genetics have been shown to contribute to differences in political ideology and strength of party politics, the portion of variation in political affiliation explained by activity in the amygdala and insula is significantly larger, suggesting that affiliating with a political party and engaging in a partisan environment may alter the brain, above and beyond the effect of heredity.”

These results may pave the way for new research on voter behaviour, yielding better understanding of the differences in how liberals and conservatives think. According to Dr. Schreiber: “The ability to accurately predict party politics using only brain activity while gambling suggests that investigating basic neural differences between voters may provide us with more powerful insights than the traditional tools of political science.”

Journal Reference:

  1. Darren Schreiber, Greg Fonzo, Alan N. Simmons, Christopher T. Dawes, Taru Flagan, James H. Fowler, Martin P. Paulus. Red Brain, Blue Brain: Evaluative Processes Differ in Democrats and RepublicansPLoS ONE, 2013; 8 (2): e52970 DOI:10.1371/journal.pone.0052970

Books Change How a Child’s Brain Grows (Wired)

By Moheb Costandi, ScienceNOW – October 18, 2012

Image: Peter Dedina/Flickr

NEW ORLEANS, LOUISIANA — Books and educational toys can make a child smarter, but they also influence how the brain grows, according to new research presented here on Sunday at the annual meeting of the Society for Neuroscience. The findings point to a “sensitive period” early in life during which the developing brain is strongly influenced by environmental factors.

Studies comparing identical and nonidentical twins show that genes play an important role in the development of the cerebral cortex, the thin, folded structure that supports higher mental functions. But less is known about how early life experiences influence how the cortex grows.

To investigate, neuroscientist Martha Farah of the University of Pennsylvania and her colleagues recruited 64 children from a low-income background and followed them from birth through to late adolescence. They visited the children’s homes at 4 and 8 years of age to evaluate their environment, noting factors such as the number of books and educational toys in their houses, and how much warmth and support they received from their parents.

More than 10 years after the second home visit, the researchers used MRI to obtain detailed images of the participants’ brains. They found that the level of mental stimulation a child receives in the home at age 4 predicted the thickness of two regions of the cortex in late adolescence, such that more stimulation was associated with a thinner cortex. One region, the lateral inferior temporal gyrus, is involved in complex visual skills such as word recognition.

Home environment at age 8 had a smaller impact on development of these brain regions, whereas other factors, such as the mother’s intelligence and the degree and quality of her care, had no such effect.

Previous work has shown that adverse experiences, such as childhood neglect, abuse, and poverty, can stunt the growth of the brain. The new findings highlight the sensitivity of the growing brain to environmental factors, Farah says, and provide strong evidence that subtle variations in early life experience can affect the brain throughout life.

As the brain develops, it produces more synapses, or neuronal connections, than are needed, she explains. Underused connections are later eliminated, and this elimination process, called synaptic pruning, is highly dependent upon experience. The findings suggest that mental stimulation in early life increases the extent to which synaptic pruning occurs in the lateral temporal lobe. Synaptic pruning reduces the volume of tissue in the cortex. This makes the cortex thinner, but it also makes information processing more efficient.

“This is a first look at how nurture influences brain structure later in life,” Farah reported at the meeting. “As with all observational studies, we can’t really speak about causality, but it seems likely that cognitive stimulation experienced early in life led to changes in cortical thickness.”

She adds, however, that the research is still in its infancy, and that more work is needed to gain a better understanding of exactly how early life experiences impact brain structure and function.

The findings add to the growing body of evidence that early life is a period of “extreme vulnerability,” says psychiatrist Jay Giedd, head of the brain imaging unit in the Child Psychiatry Branch at the National Institute of Mental Health in Bethesda, Maryland. But early life, he says, also offers a window of opportunity during which the effects of adversity can be offset. Parents can help young children develop their cognitive skills by providing a stimulating environment.

Irony Seen Through the Eye of MRI (Science Daily)

ScienceDaily (Aug. 3, 2012) — In the cognitive sciences, the capacity to interpret the intentions of others is called “Theory of Mind” (ToM). This faculty is involved in the understanding of language, in particular by bridging the gap between the meaning of the words that make up a statement and the meaning of the statement as a whole.

In recent years, researchers have identified the neural network dedicated to ToM, but no one had yet demonstrated that this set of neurons is specifically activated by the process of understanding of an utterance. This has now been accomplished: a team from L2C2 (Laboratoire sur le Langage, le Cerveau et la Cognition, Laboratory on Language, the Brain and Cognition, CNRS / Université Claude Bernard-Lyon 1) has shown that the activation of the ToM neural network increases when an individual is reacting to ironic statements.

Published in Neuroimage, these findings represent an important breakthrough in the study of Theory of Mind and linguistics, shedding light on the mechanisms involved in interpersonal communication.

In our communications with others, we are constantly thinking beyond the basic meaning of words. For example, if asked, “Do you have the time?” one would not simply reply, “Yes.” The gap between what is saidand what it means is the focus of a branch of linguistics called pragmatics. In this science, “Theory of Mind” (ToM) gives listeners the capacity to fill this gap. In order to decipher the meaning and intentions hidden behind what is said, even in the most casual conversation, ToM relies on a variety of verbal and non-verbal elements: the words used, their context, intonation, “body language,” etc.

Within the past 10 years, researchers in cognitive neuroscience have identified a neural network dedicated to ToM that includes specific areas of the brain: the right and left temporal parietal junctions, the medial prefrontal cortex and the precuneus. To identify this network, the researchers relied primarily on non-verbal tasks based on the observation of others’ behavior[1]. Today, researchers at L2C2 (Laboratoire sur le Langage, le Cerveau et la Cognition, Laboratory on Language, the Brain and Cognition, CNRS / Université Claude Bernard-Lyon 1) have established, for the first time, the link between this neural network and the processing of implicit meanings.

To identify this link, the team focused their attention on irony. An ironic statement usually means the opposite of what is said. In order to detect irony in a statement, the mechanisms of ToM must be brought into play. In their experiment, the researchers prepared 20 short narratives in two versions, one literal and one ironic. Each story contained a key sentence that, depending on the version, yielded an ironic or literal meaning. For example, in one of the stories an opera singer exclaims after a premiere, “Tonight we gave a superb performance.” Depending on whether the performance was in fact very bad or very good, the statement is or is not ironic.

The team then carried out functional magnetic resonance imaging (fMRI) analyses on 20 participants who were asked to read 18 of the stories, chosen at random, in either their ironic or literal version. The participants were not aware that the test concerned the perception of irony. The researchers had predicted that the participants’ ToM neural networks would show increased activity in reaction to the ironic sentences, and that was precisely what they observed: as each key sentence was read, the network activity was greater when the statement was ironic. This shows that this network is directly involved in the processes of understanding irony, and, more generally, in the comprehension of language.

Next, the L2C2 researchers hope to expand their research on the ToM network in order to determine, for example, whether test participants would be able to perceive irony if this network were artificially inactivated.

Note:

[1] For example, Grèzes, Frith & Passingham (J. Neuroscience, 2004) showed a series of short (3.5 second) films in which actors came into a room and lifted boxes. Some of the actors were instructed to act as though the boxes were heavier (or lighter) than they actually were. Having thus set up deceptive situations, the experimenters asked the participants to determine if they had or had not been deceived by the actors in the films. The films containing feigned actions elicited increased activity in the rTPJ (right temporal parietal junction) compared with those containing unfeigned actions.

Journal Reference:

Nicola Spotorno, Eric Koun, Jérôme Prado, Jean-Baptiste Van Der Henst, Ira A. Noveck. Neural evidence that utterance-processing entails mentalizing: The case of ironyNeuroImage, 2012; 63 (1): 25 DOI:10.1016/j.neuroimage.2012.06.046

Brain Imaging Can Predict How Intelligent You Are: ‘Global Brain Connectivity’ Explains 10 Percent of Variance in Individual Intelligence (Science Daily)

ScienceDaily (Aug. 1, 2012) — When it comes to intelligence, what factors distinguish the brains of exceptionally smart humans from those of average humans?

New research suggests as much as 10 percent of individual variances in human intelligence can be predicted based on the strength of neural connections between the lateral prefrontal cortex and other regions of the brain. (Credit: WUSTL Image / Michael Cole)

As science has long suspected, overall brain size matters somewhat, accounting for about 6.7 percent of individual variation in intelligence. More recent research has pinpointed the brain’s lateral prefrontal cortex, a region just behind the temple, as a critical hub for high-level mental processing, with activity levels there predicting another 5 percent of variation in individual intelligence.

Now, new research from Washington University in St. Louis suggests that another 10 percent of individual differences in intelligence can be explained by the strength of neural pathways connecting the left lateral prefrontal cortex to the rest of the brain.

Published in the Journal of Neuroscience, the findings establish “global brain connectivity” as a new approach for understanding human intelligence.

“Our research shows that connectivity with a particular part of the prefrontal cortex can predict how intelligent someone is,” suggests lead author Michael W. Cole, PhD, a postdoctoral research fellow in cognitive neuroscience at Washington University.

The study is the first to provide compelling evidence that neural connections between the lateral prefrontal cortex and the rest of the brain make a unique and powerful contribution to the cognitive processing underlying human intelligence, says Cole, whose research focuses on discovering the cognitive and neural mechanisms that make human behavior uniquely flexible and intelligent.

“This study suggests that part of what it means to be intelligent is having a lateral prefrontal cortex that does its job well; and part of what that means is that it can effectively communicate with the rest of the brain,” says study co-author Todd Braver, PhD, professor of psychology in Arts & Sciences and of neuroscience and radiology in the School of Medicine. Braver is a co-director of the Cognitive Control and Psychopathology Lab at Washington University, in which the research was conducted.

One possible explanation of the findings, the research team suggests, is that the lateral prefrontal region is a “flexible hub” that uses its extensive brain-wide connectivity to monitor and influence other brain regions in a goal-directed manner.

“There is evidence that the lateral prefrontal cortex is the brain region that ‘remembers’ (maintains) the goals and instructions that help you keep doing what is needed when you’re working on a task,” Cole says. “So it makes sense that having this region communicating effectively with other regions (the ‘perceivers’ and ‘doers’ of the brain) would help you to accomplish tasks intelligently.”

While other regions of the brain make their own special contribution to cognitive processing, it is the lateral prefrontal cortex that helps coordinate these processes and maintain focus on the task at hand, in much the same way that the conductor of a symphony monitors and tweaks the real-time performance of an orchestra.

“We’re suggesting that the lateral prefrontal cortex functions like a feedback control system that is used often in engineering, that it helps implement cognitive control (which supports fluid intelligence), and that it doesn’t do this alone,” Cole says.

The findings are based on an analysis of functional magnetic resonance brain images captured as study participants rested passively and also when they were engaged in a series of mentally challenging tasks associated with fluid intelligence, such as indicating whether a currently displayed image was the same as one displayed three images ago.

Previous findings relating lateral prefrontal cortex activity to challenging task performance were supported. Connectivity was then assessed while participants rested, and their performance on additional tests of fluid intelligence and cognitive control collected outside the brain scanner was associated with the estimated connectivity.

Results indicate that levels of global brain connectivity with a part of the left lateral prefrontal cortex serve as a strong predictor of both fluid intelligence and cognitive control abilities.

Although much remains to be learned about how these neural connections contribute to fluid intelligence, new models of brain function suggested by this research could have important implications for the future understanding — and perhaps augmentation — of human intelligence.

The findings also may offer new avenues for understanding how breakdowns in global brain connectivity contribute to the profound cognitive control deficits seen in schizophrenia and other mental illnesses, Cole suggests.

Other co-authors include Tal Yarkoni, PhD, a postdoctoral fellow in the Department of Psychology and Neuroscience at the University of Colorado at Boulder; Grega Repovs, PhD, professor of psychology at the University of Ljubljana, Slovenia; and Alan Anticevic, an associate research scientist in psychiatry at Yale University School of Medicine.

Funding from the National Institute of Mental Health supported the study (National Institutes of Health grants MH66088, NR012081, MH66078, MH66078-06A1W1, and 1K99MH096801).