Category: Brain Injury

Despite an increase in media attention, as well as national and local efforts to educate athletes on the potential dangers of traumatic brain injuries, a new study found that many high school football players are not concerned about the long-term effects of concussions and don't report their own concussion symptoms because they fear exclusion from play.

The abstract, "Awareness and Attitudes of High School Athletes Towards Concussions," was presented on Oct. 22, at the American Academy of Pediatrics (AAP) National Conference and Exhibition in New Orleans.

Researchers provided high school varsity football players with an Internet link to a confidential survey. The survey asked players about their previous concussion history, level of comfort in recognizing concussion symptoms, awareness of potential long-term health risks, and whether or not their attitudes on concussions had changed with the recent influx of information and warnings.

Of the 134 players who completed the survey, 10 percent reported that they had been diagnosed with a concussion by a physician or team trainer, while 32 percent reported they had concussion-like symptoms at some point over the past two years but did not seek medical attention. More than half of the respondents said they did not seek attention due to concerns of being excluded from play. Seventy-one percent of the athletes noted that they were more aware of concussion symptoms than they were when entering high school; however, less than half reported they are more likely to report symptoms despite this increased awareness.

"Interestingly, 85 percent of respondents noted that they received a majority of their concussion knowledge from their coach or trainer, while less than 10 percent obtained information from media outlets including TV, newspapers, magazines, and the Internet," said study author Michael Israel, MD, of the University of Arkansas for Medical Sciences.

Overall, the study showed that while the growing media attention has increased the awareness of high school athletes, there has been only a marginal change in student athlete behaviors and concerns for possible health consequences, Israel said. "New evidence about sports-related concussions is constantly being produced, and we as a medical community need to do a better job of disseminating this information to coaches, trainers, and athletic associations to help ensure the safety of their athletes," he said.

Blood-circulating immune cells can take over the essential immune surveillance of the brain, this is shown by scientists of the German Center for Neurodegenerative Diseases (DZNE) and the Hertie Institute for Clinical Brain Research in Tübingen. Their study, now published in PNAS, might indicate new ways of dealing with diseases of the nervous system.

The immune system is composed of multiple cell types each capable of specialized functions to protect the body from invading pathogens and promote tissue repair after injury. One cell type, known as monocytes, circulates throughout the organism in the blood and enters tissues to actively phagocytose (eat) foreign cells and assist in tissue healing. While monocytes can freely enter most bodily tissues, the healthy, normal brain is different as it is sequestered from circulating blood by a tight network of cells known as the blood brain barrier. Thus, the brain must maintain a highly specialized, resident immune cell, known as microglia, to remove harmful invaders and respond to tissue damage.

In certain situations, such as during disease, monocytes can enter the brain and also contribute to tissue repair or disease progression. However, the potential for monocytes to actively replace old or injured microglia is under considerable debate. To address this, Nicholas Varvel, Stefan Grathwohl and colleagues from the German Center for Neurodegenerative Diseases (DZNE) Tübingen and the Hertie Institute for Clinical Brain Research in Tübingen used a transgenic mouse model in which almost all brain microglia cells (>95%) can be removed within two weeks. This was done by introducing a so-called suicide gene into microglia cells and administering a pharmaceutical agent that leads to acute death of the cells. Surprisingly, after the ablation of the microglia, the brain was rapidly repopulated by blood-circulating monocytes. The monocytes appeared similar, but not identical to resident microglia. The newly populated monocytes, evenly dispersed throughout the brain, responded to acute neuronal injury and other stimuli — all activities normally assumed by microglia. Most interestingly, the monocytes were still present in the brain six months — nearly a quarter of the life of a laboratory mouse — after initial colonization.

These studies now published in PNAS provide evidence that blood-circulating monocytes can replace brain resident microglia and take over the essential immune surveillance of the brain. Furthermore, the findings highlight a strong homeostatic mechanism to maintain a resident immune cell within the brain. The observation that the monocytes took up long-term residence in the brain raises the possibility that these cells can be utilized to deliver therapeutic agents into the diseased brain or replace microglia when they become dysfunctional. Can monocytes be exploited to combat the consequences of Alzheimer's disease and other neurodegenerative diseases? The scientists and their colleagues in the research groups headed by Mathias Jucker are now following exactly this research avenue.

The Who asked "who are you?" but Dartmouth neurobiologist Jeffrey Taube asks "where are you?" and "where are you going?" Taube is not asking philosophical or theological questions. Rather, he is investigating nerve cells in the brain that function in establishing one's location and direction.

Taube, a professor in the Department of Psychological and Brain Sciences, is using microelectrodes to record the activity of cells in a rat's brain that make possible spatial navigation — how the rat gets from one place to another — from "here" to "there." But before embarking to go "there," you must first define "here."

Survival Value

"Knowing what direction you are facing, where you are, and how to navigate are really fundamental to your survival," says Taube. "For any animal that is preyed upon, you'd better know where your hole in the ground is and how you are going to get there quickly. And you also need to know direction and location to find food resources, water resources, and the like."

Not only is this information fundamental to your survival, but knowing your spatial orientation at a given moment is important in other ways, as well. Taube points out that it is a sense or skill that you tend to take for granted, which you subconsciously keep track of. "It only comes to your attention when something goes wrong, like when you look for your car at the end of the day and you can't find it in the parking lot," says Taube.

Perhaps this is a momentary lapse, a minor navigational error, but it might also be the result of brain damage due to trauma or a stroke, or it might even be attributable to the onset of a disease such as Alzheimer's. Understanding the process of spatial navigation and knowing its relevant areas in the brain may be crucial to dealing with such situations.

The Cells Themselves

One critical component involved in this process is the set of neurons called "head direction cells." These cells act like a compass based on the direction your head is facing. They are located in the thalamus, a structure that sits on top of the brainstem, near the center of the brain.

He is also studying neurons he calls "place cells." These cells work to establish your location relative to some landmarks or cues in the environment. The place cells are found in the hippocampus, part of the brain's temporal lobe. They fire based not on the direction you are facing, but on where you are located.

Studies were conducted using implanted microelectrodes that enabled the monitoring of electrical activity as these different cell types fired.

Taube explains that the two populations — the head direction cells and the place cells — talk to one another. "They put that information together to give you an overall sense of 'here,' location wise and direction wise," he says. "That is the first ingredient for being able to ask the question, 'How am I going to get to point B if I am at point A?' It is the starting point on the cognitive map."

The Latest Research

Taube and Stephane Valerio, his postdoctoral associate for the last four years, have just published a paper in the journal Nature Neuroscience, highlighting the head direction cells. Valerio has since returned to the Université Bordeaux in France.

The studies described in Nature Neuroscience discuss the responses of the spatial navigation system when an animal makes an error and arrives at a destination other than the one targeted — its home refuge, in this case. The authors describe two error-correction processes that may be called into play — resetting and remapping — differentiating them based on the size of error the animal makes when performing the task.

When the animal makes a small error and misses the target by a little, the cells will reset to their original setting, fixing on landmarks it can identify in its landscape. "We concluded that this was an active behavioral correction process, an adjustment in performance," Taube says. "However, if the animal becomes disoriented and makes a large error in its quest for home, it will construct an entirely new cognitive map with a permanent shift in the directional firing pattern of the head direction cells." This is the "remapping."

Taube acknowledges that others have talked about remapping and resetting, but they have always regarded them as if they were the same process. "What we are trying to argue in this paper is that they are really two different, separate brain processes, and we demonstrated it empirically," he says. "To continue to study spatial navigation, in particular how you correct for errors, you have to distinguish between these two qualitatively different responses."

Taube says other investigators will use this distinction as a basis for further studies, particularly in understanding how people correct their orientation when making navigational errors.

High schools with athletic trainers have lower overall injury rates, according to a new study, "A Comparative Analysis of Injury Rates and Patterns Among Girls' Soccer and Basketball Players," presented Oct. 22 at the American Academy of Pediatrics (AAP) National Conference and Exhibition in New Orleans. In addition, athletes at schools with athletic trainers are more likely to be diagnosed with a concussion.

Researchers reviewed national sports injury data on girls' high school soccer and basketball programs with athletic trainers, between the fall of 2006 and the spring of 2009, from the Reporting Information Online (RIO™) and compared it to local Sports Injury Surveillance System (SISS) data on a sample of Chicago public high school programs without athletic trainers for the same sports and time period.

Overall injury rates were 1.73 times higher among soccer players and 1.22 times higher among basketball players in schools without athletic trainers. Recurrent injury rates were 5.7 times higher in soccer and 2.97 times higher in basketball in schools without athletic trainers. In contrast, concussion injury rates were 8.05 times higher in soccer and 4.5 times higher in basketball in schools with athletic trainers.

While less than 50 percent of U.S. high schools have athletic trainers, "this data shows the valuable role that they can play in preventing, diagnosing and managing concussions and other injuries," said Cynthia LaBella, MD, FAAP. "Athletic trainers have a skill set that is very valuable, especially now when there is such a focus on concussions and related treatment and care. Concussed athletes are more likely to be identified in schools with athletic trainers and thus more likely to receive proper treatment.

"Athletic trainers facilitate treatment of injuries and monitor recovery so that athletes are not returned to play prematurely. This likely explains the lower rates of recurrent injuries in schools with athletic trainers," said Dr. LaBella.

Ancient Greek philosophers considered the ability to "know thyself" as the pinnacle of humanity. Now, thousands of years later, neuroscientists are trying to decipher precisely how the human brain constructs our sense of self.

Self-awareness is defined as being aware of oneself, including one's traits, feelings, and behaviors. Neuroscientists have believed that three brain regions are critical for self-awareness: the insular cortex, the anterior cingulate cortex, and the medial prefrontal cortex.

However, a research team led by the University of Iowa has challenged this theory by showing that self-awareness is more a product of a diffuse patchwork of pathways in the brain — including other regions — rather than confined to specific areas.

Meet "Patient R"

The conclusions came from a rare opportunity to study a person with extensive brain damage to the three regions believed critical for self-awareness. The person, a 57-year-old, college-educated man known as "Patient R," passed all standard tests of self-awareness. He also displayed repeated self-recognition, both when looking in the mirror and when identifying himself in unaltered photographs taken during all periods of his life.

"What this research clearly shows is that self-awareness corresponds to a brain process that cannot be localized to a single region of the brain," says David Rudrauf, co-corresponding author of the paper, published online Aug. 22 in the journal PLoS ONE. "In all likelihood, self-awareness emerges from much more distributed interactions among networks of brain regions."

The authors believe the brainstem, thalamus, and posteromedial cortices play roles in self-awareness, as has been theorized.

Introspection and agency

The researchers observed that Patient R's behaviors and communication often reflected depth and self-insight. First author Carissa Philippi, who earned her doctorate in neuroscience at the UI in 2011, conducted a detailed self-awareness interview with Patient R and found he had a deep capacity for introspection, one of humans' most evolved features of self-awareness.

"During the interview, I asked him how he would describe himself to somebody," says Philippi, now a postdoctoral research scholar at the University of Wisconsin-Madison. "He said, 'I am just a normal person with a bad memory.'"

Patient R also demonstrated self-agency, meaning the ability to perceive that an action is the consequence of one's own intention. When rating himself on personality measures collected over the course of a year, Patient R showed a stable ability to think about and perceive himself. However, his brain damage also affected his temporal lobes, causing severe amnesia that has disrupted his ability to update new memories into his "autobiographical self." Beyond this disruption, all other features of R's self-awareness remained fundamentally intact.

"Most people who meet R for the first time have no idea that anything is wrong with him," notes Rudrauf, a former assistant professor of neurology at the UI and now a research scientist at the INSERM Laboratory of Functional Imaging in France. "They see a normal-looking middle-aged man who walks, talks, listens, and acts no differently than the average person.

"According to previous research, this man should be a zombie," he adds. "But as we have shown, he is certainly not one. Once you've had the chance to meet him, you immediately recognize that he is self-aware."

Unique pool of patients

Patient R is a member of the UI's world-renowned Iowa Neurological Patient Registry, which was established in 1982 and has more than 500 active members with various forms of damage to one or more regions in the brain.

The researchers had begun questioning the insular cortex's role in self-awareness in a 2009 study that showed that Patient R was able to feel his own heartbeat, a process termed "interoceptive awareness."

The UI researchers estimate that Patient R has ten percent of tissue remaining in his insula and one percent of tissue remaining in his anterior cingulate cortex. Some had seized upon the presence of tissue to question whether those regions were in fact being used for self-awareness. But neuroimaging results presented in the current study reveal that Patient R's remaining tissue is highly abnormal and largely disconnected from the rest of the brain.

"Here, we have a patient who is missing all the areas in the brain that are typically thought to be needed for self-awareness yet he remains self-aware," says co-corresponding author Justin Feinstein, who earned his doctorate at the UI in February. "Clearly, neuroscience is only beginning to understand how the human brain can generate a phenomenon as complex as self-awareness."

The research team included Daniel Tranel, UI professor of neurology and psychology and director of the Neuroscience Graduate Program; Gregory Landini, UI professor of philosophy; Antonio Damasio, professor of neuroscience at the University of Southern California; Sahib Khalsa, co-chief resident of psychiatry at the University of California Los Angeles; and Kenneth Williford, associate professor of philosophy and humanities at the University of Texas at Arlington.

The National Institute of Neurological Disorders and Stroke, the National Institute on Drug Abuse, the Mathers Foundation, and the UI Carver College of Medicine funded the research.

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Journal Reference:

1. Carissa L. Philippi, Justin S. Feinstein, Sahib S. Khalsa, Antonio Damasio, Daniel Tranel, Gregory Landini, Kenneth Williford, David Rudrauf. Preserved Self-Awareness following Extensive Bilateral Brain Damage to the Insula, Anterior Cingulate, and Medial Prefrontal Cortices. PLoS ONE, 2012; 7 (8): e38413 DOI: 10.1371/journal.pone.0038413

The frontal lobes are the largest part of the human brain, and thought to be the part that expanded most during human evolution. Damage to the frontal lobes — which are located just behind and above the eyes — can result in profound impairments in higher-level reasoning and decision making. To find out more about what different parts of the frontal lobes do, neuroscientists at the California Institute of Technology (Caltech) recently teamed up with researchers at the world's largest registry of brain-lesion patients. By mapping the brain lesions of these patients, the team was able to show that reasoning and behavioral control are dependent on different regions of the frontal lobe than the areas called upon when making a decision.

Their findings are described online this week in the early edition of the Proceedings of the National Academy of Sciences (PNAS).

The team analyzed data that had been acquired over a 30-plus-year time span by scientists from the University of Iowa's department of neurology — which has the world's largest lesion patient registry. They used that data to map brain activity in nearly 350 people with damage, or lesions, in their frontal lobes. The records included data on the performances of each patient while doing certain cognitive tasks.

By examining these detailed files, the researchers were able to see exactly which parts of the frontal lobes are critical for tasks like behavioral control and decision making. The intuitive difference between these two types of processing is something we encounter in our lives all the time. Behavioral control happens when you don't order an unhealthy chocolate sundae you desire and go running instead. Decision making based on reward, on the other hand, is more like trying to win the most money in Vegas — or indeed choosing the chocolate sundae.

"These are really unique data that could not have been obtained anywhere else in the world," explains Jan Glascher, lead author of the study and a visiting associate in psychology at Caltech. "To address the question that we were interested in, we needed both a large number of patients with very well-measured lesions in the brain, and also a very thorough assessment of their reasoning and decision-making abilities across a battery of tasks."

That quantification of the lesions as well as the different task measurements came from several decades of work led by two coauthors on the study: Hanna Damasio, Dana Dornsife Chair in Neuroscience at the University of Southern California (USC); and Daniel Tranel, professor or neurology and psychology at the University of Iowa.

"The patterns of lesions that impair specific tasks showed a very clear separation between those regions of the frontal lobes necessary for controlling behavior, and those necessary for how we give value to choices and how we make decisions," says Tranel.

Ralph Adolphs, Bren Professor of Psychology and Neuroscience at Caltech and a coauthor of the study, says that aspects of what the team found had been observed previously using fMRI methods in healthy people. But, he adds, those previous studies only showed which parts of the brain are activated when people think or choose, but not which are the most critical areas, and which are less important.

"Only lesion mapping, like we did in the present study, can show you which parts of the brain are actually necessary for a particular task," he says. "This information is crucial, not only for basic cognitive neuroscience, but also for linking these findings to clinical relevance."

For example, several different parts of the brain might be activated when you are making a particular type of decision, explains Adolphs. If there is a lesion in one of these areas, the rest of your brain might be able to compensate, leaving little or no impairment. But if a lesion occurs in another area, you might wind up with a lifelong disability in decision making. Knowing which lesion leads to which outcome is something only this kind of detailed lesion study can provide, he says.

"That knowledge will be tremendously useful for prognosis after brain injury," says Adolphs. "Many people suffer injury to their frontal lobes — for instance, after a head injury during an automobile accident — but the precise pattern of the damage will determine their eventual impairment."

According to Tranel, the team is already working on their next project, which will use lesion mapping to look at how damage to particular brain regions can impact mood and personality. " There are so many other aspects of human behavior, cognition, and emotion to investigate here, that we've barely begun to scratch the surface," he says.

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Journal Reference:

1. J. Glascher, R. Adolphs, H. Damasio, A. Bechara, D. Rudrauf, M. Calamia, L. K. Paul, D. Tranel. Lesion mapping of cognitive control and value-based decision making in the prefrontal cortex. Proceedings of the National Academy of Sciences, 2012; DOI: 10.1073/pnas.1206608109

Scientists at UCLA and the Technion, Israel's Institute of Technology, have unraveled how our brain cells encode the pronunciation of individual vowels in speech. Published in the Aug. 21 edition of Nature Communications, the discovery could lead to new technology that verbalizes the unspoken words of people paralyzed by injury or disease.

"We know that brain cells fire in a predictable way before we move our bodies," explained Dr. Itzhak Fried, a professor of neurosurgery at the David Geffen School of Medicine at UCLA. "We hypothesized that neurons would also react differently when we pronounce specific sounds. If so, we may one day be able to decode these unique patterns of activity in the brain and translate them into speech."

Fried and Technion's Ariel Tankus, formerly a postdoctoral researcher in Fried's lab, followed 11 UCLA epilepsy patients who had electrodes implanted in their brains to pinpoint the origin of their seizures. The researchers recorded neuron activity as the patients uttered one of five vowels or syllables containing the vowels.

With Technion's Shy Shoham, the team studied how the neurons encoded vowel articulation at both the single-cell and collective level. The scientists found two areas — the superior temporal gyrus and a region in the medial frontal lobe — that housed neurons related to speech and attuned to vowels. The encoding in these sites, however, unfolded very differently.

Neurons in the superior temporal gyrus responded to all vowels, although at different rates of firing. In contrast, neurons that fired exclusively for only one or two vowels were located in the medial frontal region.

"Single neuron activity in the medial frontal lobe corresponded to the encoding of specific vowels," said Fried. "The neuron would fire only when a particular vowel was spoken, but not other vowels."

At the collective level, neurons' encoding of vowels in the superior temporal gyrus reflected the anatomy that made speech possible-specifically, the tongue's position inside the mouth.

"Once we understand the neuronal code underlying speech, we can work backwards from brain-cell activity to decipher speech," said Fried. "This suggests an exciting possibility for people who are physically unable to speak. In the future, we may be able to construct neuro-prosthetic devices or brain-machine interfaces that decode a person's neuronal firing patterns and enable the person to communicate."

The study was supported by grants from the European Council, the National Institute of Neurological Disorders and Stroke, the Dana Foundation, Lady David and L. and L. Richmond research funds.

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Journal Reference:

1. Ariel Tankus, Itzhak Fried, Shy Shoham. Structured neuronal encoding and decoding of human speech features. Nature Communications, 2012; 3: 1015 DOI: 10.1038/ncomms1995

A technique called high-definition fiber tractography (HDFT) provides a powerful new tool for tracing the course of nerve fiber connections within the brain — with the potential to improve the accuracy of neurosurgical planning and to advance scientific understanding of the brain's structural and functional networks, reports a paper in the August issue of Neurosurgery, official journal of the Congress of Neurological Surgeons.

In the new report, Dr. Juan C. Fernandez-Miranda and colleagues of University of Pittsburgh describe and illustrate the use of the HDFT to track the course of the nerve fibers that make up the white matter of the brain. The researchers write, "Our HDFT approach provides an accurate reconstruction of white matter fiber tracts with unprecedented detail in both the normal and pathological human brain."

HDFT Shows White Matter Tracts in Living Brain Dr. Fernandez-Miranda and coauthors report on the development and evaluation of the HDFT technique, including initial findings in healthy people and patients with various brain lesions. The new technique adds advanced digital processing and reconstruction techniques to current methods of tractography — a method used to trace the course of bundles of white matter fibers, or "tracts," in the brain.

Tractography using a technique called diffusion tensor imaging (DTI) has been available for more than a decade. However, DTI has some important limitations: it can't show the complex course of white matter fiber tracts as they cross each other, and it can't accurately show the starting point and ending points of white matter tracts. The researchers call these the "crossing problem" and the "termination problem," respectively.

Over the past three years, Dr. Fernandez-Miranda and colleagues have been working on refining new fiber mapping techniques — such as high-angular resolution diffusion imaging and diffusion spectrum imaging — to study the structural connections of the brain. They write, "In an attempt to more effectively solve the crossing and termination problems, we have focused on optimizing these methods to obtain what we refer to as HDFT." Through a combination of imaging processing and reconstruction and tractography methods, HDFT can track white matter fiber tracts from their origin, through complex fiber crossings, to their termination point, with resolution of one millimeter or less.

For brain researchers, HDFT provides an unprecedented level of detail to solve both the crossing and termination problems. Color-coded images show the complex architecture of white matter fibers, as they cross each other in complex patterns. The HDFT images accurately replicate known features of the brain anatomy, including the folds and grooves (gyri and sulci) of the brain and the characteristic shape of brain structures.

To evaluate how the new technique might be used for surgical planning, the researchers analyzed HDFT images obtained in patients with cancers and other brain lesions. In patients with brain cancers, HDFT clearly showed the disruption of brain tissue caused by rapid tumor growth. Importantly, it was able to show the absence of white matter fibers within the tumor itself in two types of brain cancers.

In patients with brain blood vessel malformations, HDFT provided information likely to be useful in planning the safest approach to surgery. The ability to differentiate displacement versus disruption of fibers may become a critical factor in determining whether or not damage caused by brain lesions is reversible.

The researchers emphasize that much more research will be needed to refine the HDFT technique and to evaluate its scientific and clinical uses. "From a clinical perspective, we show that accurate structural connectivity studies in patients facilitate white matter damage assessment, aid in understanding lesional patterns of white matter structural damage, and allow innovative neurosurgical applications," the researchers write. They also believe that structural connections shown by HDFT will provide a useful complement to efforts to map the functional connections of brain networks, such as the Human Connectome Project.

Amputation disrupts not only the peripheral nervous system but also central structures of the brain. While the brain is able to adapt and compensate for injury in certain conditions, in amputees the traumatic event prevents adaptive cortical changes. A group of scientists reports adaptive plastic changes in an amputee's brain following implantation of multielectrode arrays inside peripheral nerves.

Their results are available in the current issue of Restorative Neurology and Neuroscience.

"We found that a neurally-interfaced hand prosthesis re-established communication between the central and peripheral nervous systems, not only restructuring the areas directly responsible for motor control but also their functional balance within the bi-hemispheric system necessary for motor control," says lead investigator Camillo Porcaro, PhD, of the Institute of Neuroscience, Newcastle University, Medical School, Newcastle upon Tyne, UK and the Institute of Cognitive Sciences and Technologies (ISTC) — National Research Council (CNR).

A 26-year old male with a left arm amputation was implanted with four microelectrode arrays in the ulnar and median nerves of his stump for four weeks. Prior to implantation, he was trained for two weeks by video to perform three specific movements with his phantom hand. During the experimental period, he underwent intensive training to control a hand prosthesis using the implanted microelectrodes to perform the same hand grip tasks. Together with visual feedback from the prosthesis, the patient received sensory feedback from an experimenter, who delivered electrical pulses to the nerves activated by each movement. EEG signals were recorded as the patient moved his right hand and the prosthesis.

The patient's right hand movement showed clear activation of the primary sensory and motor areas for right hand movement, on the left side of the brain. Prior to implantation, commands to move the phantom left hand triggered the primary sensory and motor areas on the left side of the brain, and the pre-motor and supplementary motor cortices on both sides of the brain. No primary motor cortex movement was found on the right side of the brain, as would be expected.

After the four weeks of prosthesis motor control training with implanted microelectrodes, cerebral activation changed markedly. Cortical recruitment became almost symmetrical with right hand movements. The presence of intra-fascicular electrodes allowed new signals to be delivered through peripheral nerves towards the cortex and produced an intensive exchange of sensori-motor afferent and efferent inputs and outputs. Four weeks of training led to a new functional recruitment of sensorimotor areas devoted to hand control.

"Taken together, the results of this study confirm that neural interfaces are optimal candidates for hand prosthesis control," says Dr. Porcaro. "They establish communication channels needed for natural control of the prosthesis. Furthermore, neural interfaces recreate the connection with the environment that promotes restorative neuroplasticity. Bi-hemispheric networks regain the physiological communication necessary for motor control."

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Journal Reference:

1. G. DiPino, C. Porcaro, M. Tombini, G. Assenza, G. Pellegrino, F. Tecchio, P.M. Rossini. A neurally -interfaced hand prosthesis tuned inter-hemispheric communication. Restorative Neurology and Neuroscience, September 2012 DOI: 10.3233/RNN-2012-120224

Everyone knows the adage: "If something sounds too good to be true, then it probably is." Why, then, do some people fall for scams and why are older folks especially prone to being duped?

An answer, it seems, is because a specific area of the brain has deteriorated or is damaged, according to researchers at the University of Iowa. By examining patients with various forms of brain damage, the researchers report they've pinpointed the precise location in the human brain, called the ventromedial prefrontal cortex, that controls belief and doubt, and which explains why some of us are more gullible than others.

"The current study provides the first direct evidence beyond anecdotal reports that damage to the vmPFC (ventromedial prefrontal cortex) increases credulity. Indeed, this specific deficit may explain why highly intelligent vmPFC patients can fall victim to seemingly obvious fraud schemes," the researchers wrote in the paper published in a special issue of the journal Frontiers in Neuroscience.

A study conducted for the National Institute of Justice in 2009 concluded that nearly 12 percent of Americans 60 and older had been exploited financially by a family member or a stranger. And, a report last year by insurer MetLife Inc. estimated the annual loss by victims of elder financial abuse at $2.9 billion.

The authors point out their research can explain why the elderly are vulnerable.

"In our theory, the more effortful process of disbelief (to items initially believed) is mediated by the vmPFC, which, in old age, tends to disproportionately lose structural integrity and associated functionality," they wrote. "Thus, we suggest that vulnerability to misleading information, outright deception and fraud in older adults is the specific result of a deficit in the doubt process that is mediated by the vmPFC."

The ventromedial prefrontal cortex is an oval-shaped lobe about the size of a softball lodged in the front of the human head, right above the eyes. It's part of a larger area known to scientists since the extraordinary case of Phineas Gage that controls a range of emotions and behaviors, from impulsivity to poor planning. But brain scientists have struggled to identify which regions of the prefrontal cortex govern specific emotions and behaviors, including the cognitive seesaw between belief and doubt.

The UI team drew from its Neurological Patient Registry, which was established in 1982 and has more than 500 active members with various forms of damage to one or more regions in the brain. From that pool, the researchers chose 18 patients with damage to the ventromedial prefrontal cortex and 21 patients with damage outside the prefrontal cortex. Those patients, along with people with no brain damage, were shown advertisements mimicking ones flagged as misleading by the Federal Trade Commission to test how much they believed or doubted the ads. The deception in the ads was subtle; for example, an ad for "Legacy Luggage" that trumpets the gear as "American Quality" turned on the consumer's ability to distinguish whether the luggage was manufactured in the United States versus inspected in the country.

Each participant was asked to gauge how much he or she believed the deceptive ad and how likely he or she would buy the item if it were available. The researchers found that the patients with damage to the ventromedial prefrontal cortex were roughly twice as likely to believe a given ad, even when given disclaimer information pointing out it was misleading. And, they were more likely to buy the item, regardless of whether misleading information had been corrected.

"Behaviorally, they fail the test to the greatest extent," says Natalie Denburg, assistant professor in neurology who devised the ad tests. "They believe the ads the most, and they demonstrate the highest purchase intention. Taken together, it makes them the most vulnerable to being deceived." She added the sample size is small and further studies are warranted.

Apart from being damaged, the ventromedial prefrontal cortex begins to deteriorate as people reach age 60 and older, although the onset and the pace of deterioration varies, says Daniel Tranel, neurology and psychology professor at the UI and corresponding author on the paper. He thinks the finding will enable doctors, caregivers, and relatives to be more understanding of decision making by the elderly.

"And maybe protective," Tranel adds. "Instead of saying, 'How would you do something silly and transparently stupid,' people may have a better appreciation of the fact that older people have lost the biological mechanism that allows them to see the disadvantageous nature of their decisions."

The finding corroborates an idea studied by the paper's first author, Erik Asp, who wondered why damage to the prefrontal cortex would impair the ability to doubt but not the initial belief as well. Asp created a model, which he called the False Tagging Theory, to separate the two notions and confirm that doubt is housed in the prefrontal cortex.

"This study is strong empirical evidence suggesting that the False Tagging Theory is correct," says Asp, who earned his doctorate in neuroscience from the UI in May and is now at the University of Chicago.

Kenneth Manzel, Bryan Koestner, and Catherine Cole from the UI are contributing authors on the paper. The National Institute on Aging and the National Institute of Neurological Disorders and Stroke funded the research.

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Journal Reference:

1. Erik Asp, Kenneth Manzel, Bryan Koestner, Catherine A. Cole, Natalie L. Denburg, Daniel Tranel. A Neuropsychological Test of Belief and Doubt: Damage to Ventromedial Prefrontal Cortex Increases Credulity for Misleading Advertising. Frontiers in Neuroscience, 2012; 6 DOI: 10.3389/fnins.2012.00100