ScienceDaily (July 5, 2012) — Sensory substitution devices (SSDs) use sound or touch to help the visually impaired perceive the visual scene surrounding them. The ideal SSD would assist not only in sensing the environment but also in performing daily activities based on this input. For example, accurately reaching for a coffee cup, or shaking a friend’s hand. In a new study, scientists trained blindfolded sighted participants to perform fast and accurate movements using a new SSD, called EyeMusic. Their results are published in the July issue of Restorative Neurology and Neuroscience.

Left: An illustration of the EyeMusic SSD, showing a user with a camera mounted on the glasses, and scalp headphones, hearing musical notes that create a mental image of the visual scene in front of him. He is reaching for the red apple in a pile of green ones. Top right: close-up of the glasses-mounted camera and headphones; bottom right: hand-held camera pointed at the object of interest. (Credit: Maxim Dupliy, Amir Amedi and Shelly Levy-Tzedek)

The EyeMusic, developed by a team of researchers at the Hebrew University of Jerusalem, employs pleasant musical tones and scales to help the visually impaired “see” using music. This non-invasive SSD converts images into a combination of musical notes, or “soundscapes.”

The device was developed by the senior author Prof. Amir Amedi and his team at the Edmond and Lily Safra Center for Brain Sciences (ELSC) and the Institute for Medical Research Israel-Canada at the Hebrew University. The EyeMusic scans an image and represents pixels at high vertical locations as high-pitched musical notes and low vertical locations as low-pitched notes according to a musical scale that will sound pleasant in many possible combinations. The image is scanned continuously, from left to right, and an auditory cue is used to mark the start of the scan. The horizontal location of a pixel is indicated by the timing of the musical notes relative to the cue (the later it is sounded after the cue, the farther it is to the right), and the brightness is encoded by the loudness of the sound.

The EyeMusic’s algorithm uses different musical instruments for each of the five colors: white (vocals), blue (trumpet), red (reggae organ), green (synthesized reed), yellow (violin); Black is represented by silence. Prof. Amedi mentions that “The notes played span five octaves and were carefully chosen by musicians to create a pleasant experience for the users.” Sample sound recordings are available at http://brain.huji.ac.il/em/.

"We demonstrated in this study that the EyeMusic, which employs pleasant musical scales to convey visual information, can be used after a short training period (in some cases, less than half an hour) to guide movements, similar to movements guided visually," explain lead investigators Drs. Shelly Levy-Tzedek, an ELSC researcher at the Faculty of Medicine, Hebrew University, Jerusalem, and Prof. Amir Amedi. "The level of accuracy reached in our study indicates that performing daily tasks with an SSD is feasible, and indicates a potential for rehabilitative use."

The study tested the ability of 18 blindfolded sighted individuals to perform movements guided by the EyeMusic, and compared those movements to those performed with visual guidance. At first, the blindfolded participants underwent a short familiarization session, where they learned to identify the location of a single object (a white square) or of two adjacent objects (a white and a blue square).

In the test sessions, participants used a stylus on a digitizing tablet to point to a white square located either in the north, the south, the east or the west. In one block of trials they were blindfolded (SSD block), and in the other block (VIS block) the arm was placed under an opaque cover, so they could see the screen but did not have direct visual feedback from the hand. The endpoint location of their hand was marked by a blue square. In the SSD block, they received feedback via the EyeMusic. In the VIS block, the feedback was visual.

"Participants were able to use auditory information to create a relatively precise spatial representation," notes Dr. Levy-Tzedek.

The study lends support to the hypothesis that representation of space in the brain may not be dependent on the modality with which the spatial information is received, and that very little training is required to create a representation of space without vision, using sounds to guide fast and accurate movements. “SSDs may have great potential to provide detailed spatial information for the visually impaired, allowing them to interact with their external environment and successfully make movements based on this information, but further research is now required to evaluate the use of our device in the blind ” concludes Dr. Levy-Tzedek. These results demonstrate the potential application of the EyeMusic in performing everyday tasks — from accurately reaching for the red (but not the green!) apples in the produce aisle, to, perhaps one day, playing a Kinect / Xbox game.

Source: Science Daily

July 5, 2012

Feeling full involves more than just the uncomfortable sensation that your waistband is getting tight. Investigators reporting online on July 5th in the Cell Press journal Cell have now mapped out the signals that travel between your gut and your brain to generate the feeling of satiety after eating a protein-rich meal. Understanding this back and forth loop between the brain and gut may pave the way for future approaches in the treatment and/or prevention of obesity.

Feeling full involves more than just the uncomfortable sensation that your waistband is getting tight. Investigators reporting online on July 5th in the Cell Press journal Cell have now mapped out the signals that travel between your gut and your brain to generate the feeling of satiety after eating a protein-rich meal. Understanding this back and forth loop between the brain and gut may pave the way for future approaches in the treatment and/or prevention of obesity. Credit: Duraffourd et al., Cell

Food intake can be modulated through mu-opioid receptors (MORs, which also bind morphine) on nerves found in the walls of the portal vein, the major blood vessel that drains blood from the gut. Specifically, stimulating the receptors enhances food intake, while blocking them suppresses intake. Investigators have now found that peptides, the products of digested dietary proteins, block MORs, curbing appetite. The peptides send signals to the brain that are then transmitted back to the gut to stimulate the intestine to release glucose, suppressing the desire to eat.

Mice that were genetically engineered to lack MORs did not carry out this release of glucose, nor did they show signs of ‘feeling full’, after eating high-protein foods. Giving them MOR stimulators or inhibitors did not affect their food intake, unlike normal mice.

Because MORs are also present in the neurons lining the walls of the portal vein in humans, the mechanisms uncovered here may also take place in people.

"These findings explain the satiety effect of dietary protein, which is a long-known but unexplained phenomenon,” says senior author Dr. Gilles Mithieux of the Université de Lyon, in France. “They provide a novel understanding of the control of food intake and of hunger sensations, which may offer novel approaches to treat obesity in the future,” he adds.

Provided by Cell Press

Source: medicalxpress.com

ScienceDaily (July 5, 2012) — The widely used diabetes drug metformin comes with a rather unexpected and alluring side effect: it encourages the growth of new neurons in the brain. The study reported in the July 6th issue of Cell Stem Cell, a Cell Press publication, also finds that those neural effects of the drug also make mice smarter.

New research finds that the widely used diabetes drug metformin comes with a rather unexpected and alluring side effect: it encourages the growth of new neurons in the brain. (Credit: iStockphoto/Guido Vrola)

The discovery is an important step toward therapies that aim to repair the brain not by introducing new stem cells but rather by spurring those that are already present into action, says the study’s lead author Freda Miller of the University of Toronto-affiliated Hospital for Sick Children. The fact that it’s a drug that is so widely used and so safe makes the news all that much better.

Earlier work by Miller’s team highlighted a pathway known as aPKC-CBP for its essential role in telling neural stem cells where and when to differentiate into mature neurons. As it happened, others had found before them that the same pathway is important for the metabolic effects of the drug metformin, but in liver cells.

"We put two and two together," Miller says. If metformin activates the CBP pathway in the liver, they thought, maybe it could also do that in neural stem cells of the brain to encourage brain repair.

The new evidence lends support to that promising idea in both mouse brains and human cells. Mice taking metformin not only showed an increase in the birth of new neurons, but they were also better able to learn the location of a hidden platform in a standard maze test of spatial learning.

While it remains to be seen whether the very popular diabetes drug might already be serving as a brain booster for those who are now taking it, there are already some early hints that it may have cognitive benefits for people with Alzheimer’s disease. It had been thought those improvements were the result of better diabetes control, Miller says, but it now appears that metformin may improve Alzheimer’s symptoms by enhancing brain repair.

Miller says they now hope to test whether metformin might help repair the brains of those who have suffered brain injury due to trauma or radiation therapies for cancer.

Source: Science Daily

ScienceDaily (July 5, 2012) — Although many areas of the human brain are devoted to social tasks like detecting another person nearby, a new study has found that one small region carries information only for decisions during social interactions. Specifically, the area is active when we encounter a worthy opponent and decide whether to deceive them.

(Credit: © wtamas / Fotolia)

A brain imaging study conducted by researchers at the Duke Center for Interdisciplinary Decision Science (D-CIDES) put human subjects through a functional MRI brain scan while playing a simplified game of poker against a computer and human opponents. Using computer algorithms to sort out what amount of information each area of the brain was processing, the team found only one brain region — the temporal-parietal junction, or TPJ — carried information that was unique to decisions against the human opponent.

Some of the time, the subjects were dealt an obviously weak hand. The researchers wanted to see whether they could watch the player calculate whether to bluff his opponent. The brain signals in the TPJ told the researchers whether the subject would soon bluff against a human opponent, especially if that opponent was judged to be skilled. But against a computer, signals in the TPJ did not predict the subject’s decisions.

The TPJ is in a boundary area of the brain, and may be an intersection for two streams of information, said lead researcher McKell Carter, a postdoctoral fellow at Duke. It brings together a flow of attentional information and biological information, such as “is that another person?”

Carter observed that in general, participants paid more attention to their human opponent than their computer opponent while playing poker, which is consistent with humans’ drive to be social.

Throughout the poker game experiment, regions of the brain that are typically thought to be social in nature did not carry information specific to a social context. “The fact that all of these brain regions that should be specifically social are used in other circumstances is a testament to the remarkable flexibility and efficiency of our brains,” said Carter.

"There are fundamental neural differences between decisions in social and non-social situations," said D-CIDES Director Scott Huettel, the Hubbard professor of psychology & neuroscience at Duke and senior author of the study. "Social information may cause our brain to play by different rules than non-social information, and it will be important for both scientists and policymakers to understand what causes us to approach a decision in a social or a non-social manner.

"Understanding how the brain identifies important competitors and collaborators — those people who are most relevant for our future behavior — will lead to new insights into social phenomena like dehumanization and empathy," Huettel added.

Source: Science Daily

ScienceDaily (July 4, 2012) — A study by researchers at Universidad Carlos III de Madrid and Universidad de Zaragoza has determined that when deciding whether to cooperate with others, people do not act thinking about their own reward, as had been previously believed, but rather individuals are more influenced by their own mood at the time and by the number of individuals with whom they have cooperated before.

In addition to previous studies, this research is also based on an experiment carried out by the Institute for Biocomputation and Physics of Complex Systems (BIFI) at the Universidad de Zaragoza, together with the Fundación Ibercivis and Universidad Carlos III de Madrid (UC3M), the largest study of its kind to date in real time regarding cooperation in society. It was carried out during this past December, with 1,200 Aragon secondary students participating, who interacted electronically in real time via a social conflict prototype known as the “Prisoner’s Dilemma.” This game shows that the greatest benefit for individuals who interact is produced when both of them collaborate, but if one collaborates and the other does not, the latter will receive more benefits than the one who cooperates. On occasion, this allows an individual to take advantage of the cooperation of others, but if this tendency is extended, in the end, no one cooperates and as such, nobody obtains rewards.

After analyzing the information, the main conclusion drawn by the researchers is that in a situation where cooperating with others is beneficial, the way the individuals involved are organized into one social structure or another is irrelevant. A first analysis contradicts what many researchers have held based on theoretical studies.

In the experiment, the degree of cooperation in a network in which each subject interacts with four other individuals is compared to a network in which the number of connections vary between 2 and 16, that is, one that is more similar to a social network. What has been observed is that the results in the two networks are identical. “This happens because, contrary to what has been proposed in the majority of studies, people do not make their decisions based on the rewards obtained (by them or by their neighbors), but rather based on how many people have recently cooperated with them, as well as on their own mood at the time,” the researchers explained.

These results help understand how people make decisions, above all in the context in which one has to decide between collaborating with or taking advantage of others. “Understanding why we do one thing or another can help in designing incentives that induce people to cooperate,” the authors of the research pointed out. On the other hand, the fact that the networks are not important has implications, for organizational design, for example. The experiment revealed that people are not going to cooperate more because of being organized in a certain way. In this respect, it can be inferred that we do not have to be concerned with the design of organizational structure, but rather with motivating people individually to cooperate.

Ruling out that network organization influences in the cooperation of people, and having discovered that what is important is reciprocity, that is, cooperating according to cooperation received, will radically change the focus of a significant number of researchers who are developing theories on the emergence of cooperation among individuals.

Source: Science Daily

July 4, 2012

(Medical Xpress) — Researchers at the UCL Institute of Neurology have found that giving the drug rotigotine as a skin patch can improve inattention in some stroke patients.

Hemi-spatial neglect, a severe and common form of inattention that can be caused by brain damage following a stroke, is one of the most debilitating symptoms, frequently preventing patients from living independently. When the right side of the brain has suffered damage, the patient may have little awareness of their left-hand side and have poor memory of objects that they have seen, leaving them inattentive and forgetful. Currently there are few treatment options.

The randomised control trial took 16 patients who had suffered a stroke on the right-hand side of their brain and assessed to see whether giving the drug rotigotine improved their ability to concentrate on their left-hand side. The results showed that even with treatment for just over a week, patients who received the drug performed significantly better on attention tests than when they received the placebo treatment.

Rotigotine acts by stimulating receptors on nerve cells for dopamine, a chemical normally produced within the brain.

Professor Masud Husain who led the study at the Institute of Neurology at UCL says: “Inattention can have a devastating effect on stroke patients and their families. It impacts on all aspects of their lives. If the results of our clinical trial are replicated in further, larger studies, we will have overcome a major hurdle towards providing a new treatment for this important consequence of stroke.

“Milder forms of inattention occur in other brain disorders, across all ages - from ADHD (attention deficit hyperactivity disorder) to Parkinson’s disease. Our findings show that it is possible to alter attention by using a drug that acts at specific receptors in the brain, and therefore have implications for understanding the mechanisms that might cause inattention in conditions other than stroke.”

Provided by University College London

Source: medicalxpress.com

ScienceDaily (July 3, 2012) — University of Granada researchers have developed an artificial cerebellum (a biologically-inspired adaptive microcircuit) that controls a robotic arm with human-like precision. The cerebellum is the part of the human brain that controls the locomotor system and coordinates body movements.

To date, although robot designers have achieved very precise movements, such movements are performed at very high speed, require strong forces and are power consuming. This approach cannot be applied to robots that interact with humans, as a malfunction might be potentially dangerous.

To solve this challenge, University of Granada researchers have implemented a new cerebellar spiking model that adapts to corrections and stores their sensorial effects; in addition, it records motor commands to predict the action or movement to be performed by the robotic arm. This cerebellar model allows the user to articulate a state-of-the-art robotic arm with extraordinary mobility.

Automatic Learning

The developers of the new cerebellar model have obtained a robot that performs automatic learning by extracting the input layer functionalities of the brain cortex. Furthermore, they have developed two control systems that enable accurate and robust control of the robotic arm during object handling.

The synergy between the cerebellum and the automatic control system enables robot’s adaptability to changing conditions i.e. the robot can interact with humans. The biologically-inspired architectures used in this model combine the error training approach with predictive adaptive control.

The designers of this model are Silvia Tolu, Jesús Garrido and Eduardo Ros Vidal, at the University of Granada Department of Computer Architecture and Technology, and the University of Almería researcher Richard Carrillo.

Source: Science Daily

ScienceDaily (July 3, 2012) — When a person injures their knee, it becomes inflamed. When a person has a cold, their throat becomes inflamed. This type of inflammation is the body’s natural and protective response to injury.

Interestingly, there is growing evidence that a similar process happens when a person experiences psychological trauma. Unfortunately, this type of inflammation can be destructive.

Previous studies have linked depression and inflammation, particularly in individuals who have experienced early childhood adversity, but overall, findings have been inconsistent. Researchers Gregory Miller and Steve Cole designed a longitudinal study in an effort to resolve these discrepancies, and their findings are now published in a study in Biological Psychiatry.

They recruited a large group of female adolescents who were healthy, but at high risk for experiencing depression. The volunteers were then followed for 2 ½ years, undergoing interviews and giving blood samples to measure their levels of C-reactive protein and interleukin-6, two types of inflammatory markers. Their exposure to childhood adversity was also assessed.

The researchers found that when individuals who suffered from early childhood adversity became depressed, their depression was accompanied by an inflammatory response. In addition, among subjects with previous adversity, high levels of interleukin-6 forecasted risk of depression six months later. In subjects without childhood adversity, there was no such coupling of depression and inflammation.

Dr. Miller commented on their findings: “What’s important about this study is that it identifies a group of people who are prone to have depression and inflammation at the same time. That group of people experienced major stress in childhood, often related to poverty, having a parent with a severe illness, or lasting separation from family. As a result, these individuals may experience depressions that are especially difficult to treat.”

Another important aspect to their findings is that the inflammatory response among the high-adversity individuals was still detectable six months later, even if their depression had abated, meaning that the inflammation is chronic rather than acute. “Because chronic inflammation is involved in other health problems, like diabetes and heart disease, it also means they have greater-than-average risk for these problems. They, along with their doctors, should keep an eye out for those problems,” added Dr. Miller.

"This study provides important additional support for the notion that inflammation is an important and often under-appreciated factor that compromises resilience after major life stresses. It provides evidence that these inflammatory states persist for long periods of time and have important functional correlates," said Dr. John Krystal, Editor of Biological Psychiatry.

Further research is necessary, to extend the findings beyond female adolescents and particularly in individuals with more severe, long-term depression.. However, findings such as these may eventually help doctors and clinicians better manage depression and medical illness for particularly vulnerable patients.

Source: medicalxpress.com

ScienceDaily (July 3, 2012) — Exposure to childhood maltreatment increases the risk for most psychiatric disorders as well as many negative consequences of these conditions. This new study, by Dr. Gustavo Turecki and colleagues at McGill University, Canada, provides important insight into one of the most extreme outcomes, suicide.

"In this study, we expanded our previous work on the epigenetic regulation of the glucocorticoid receptor gene by investigating the impact of severe early-life adversity on DNA methylation," explained Dr. Turecki. The glucocorticoid receptor is important because it is a brain target for the stress hormone cortisol.

The researchers studied brain tissue from people who had committed suicide, some of whom had a history of childhood maltreatment, and compared that tissue to people who had died from other causes. They found that particular variants of the glucocorticoid receptor were less likely to be present in the limbic system, or emotion circuit, of the brain in people who had committed suicide and were maltreated as children compared to the other two groups..

This study also advances the understanding of how the altered pattern of glucocorticoid receptor regulation developed in the maltreated suicide completers. The authors found that the pattern of methylation of the gene coding for the glucocorticoid receptors was altered in those who completed suicide and who also had a history of abuse. These DNA methylation differences were associated with distinct gene expression patterns.

Since methylation is one way that genes are switched on or off for long periods of time, it appears that childhood adversity can produce long-lasting changes in the regulation of a key stress response system that may be associated with increased risk for suicide.

"Preventing suicide is a critical challenge for psychiatry. This study provides important new information about brain changes that may increase the risk of suicide," said Dr. John Krystal, Editor of Biological Psychiatry. "It is striking that early life maltreatment can produce these long-lasting changes in the control of specific genes in the brain. It is also troubling that the consequences of this process can be so dire. Thus, it is important that we continue to study these epigenetic processes that seem to underlie aspects of the lasting consequences of childhood adversity."

Source: Science Daily