Posts tagged BMI
Articles and news from the latest research reports.
"All systems go" for a paralyzed person to kick off the World Cup
The Walk Again Project is an international collaboration of more than one hundred scientists, led by Prof. Miguel Nicolelis of Duke University and the International Institute for Neurosciences of Natal, Brazil. Prof. Gordon Cheng, head of the Institute for Cognitive Systems at the Technische Universität München (TUM), is a leading partner.
Eight Brazilian patients, men and women between 20 and 40 years of age who are paralyzed from the waist down, have been training for months to use the exoskeleton. The system works by recording electrical activity in the patient’s brain, recognizing his or her intention – such as to take a step or kick a ball – and translating that to action. It also gives the patient tactile feedback using sensitive artificial skin created by Cheng’s institute.
The feeling of touching the ground
Inspiration for this so-called CellulARSkin technology – as well as for the Walk Again Project itself – came from a 2008 collaboration. As Cheng sums up that complex and widely reported experiment, “Miguel set up a monkey walking on a treadmill in North Carolina, and then I made my humanoid robot walk with the signal in Kyoto.” It was a short step for the researchers to envision a paralyzed person walking with the help of a robotic exoskeleton that could be guided by mental activity alone.
"Our brains are very adaptive in the way that we can extend our embodiment to use tools," Cheng says, "as in driving a car or eating with chopsticks. After the Kyoto experiment, we felt certain that the brain could also liberate a paralyzed person to walk using an external body." It was clear that technical advances would be required to allow a relatively compact, lightweight exoskeleton to be assembled, and that visual feedback would not be enough. A sense of touch would be essential for the patient’s emotional comfort as well as control over the exoskeleton. Thus the challenge was to give a paralyzed person, together with the ability to walk, the feeling of touching the ground.
A versatile solution
Upon joining TUM in 2010, Cheng made it a research priority for his institute to improve on the state of the art in tactile sensing for robotic systems. The result, CellulARSkin, provides a framework for a robust and self-organizing surface sensor network. It can be implemented using standard off-the-shelf hardware and thus will benefit from future improvements in miniaturization, performance, and cost.
The basic unit is a flat, six-sided package of electronic components including a low-power-consumption microprocessor as well as sensors that detect pre-touch proximity, pressure, vibration, temperature, and even movement in three-dimensional space. Any number of these individual “cells” can be networked together in a honeycomb pattern, protected in the current prototype by a rubbery skin of molded elastomer.
"It’s not just the sensor that’s important," Cheng says. "The intelligence of the sensor is even more important." Cooperation among the networked cells, and between the network and a central system, allows CellulARSkin to configure itself for each specific application and to recover automatically from certain kinds of damage. These capabilities offer advantages in enabling smarter, safer interaction of machines with people, and in rapid setup of industrial robots – as is being pursued in the EU-sponsored project "Factory in a Day."
In the Walk Again Project, CellulARSkin is being used in two ways. Integrated with the exoskeleton, for example on the bottoms of the feet, the artificial skin sends signals to tiny motors that vibrate against the patient’s arms. Through training with this kind of indirect sensory feedback, a patient can learn to incorporate the robotic legs and feet into his or her own body schema. CellulARSkin is also being wrapped around parts of the patient’s own body to help the medical team monitor for any signs of distress or discomfort.
A milestone, but “just the beginning”
"I think some people see the World Cup opening as the end," Cheng says, "but it’s really just the beginning. This may be a major milestone, but we have a lot more work to do." He views the event as a public demonstration of what science can do for people. "Also, I see it as a great tribute to all the patients’ hard work and their bravery!"
Bioengineer Studying How the Brain Controls Movement
A University of California, San Diego research team led by bioengineer Gert Cauwenberghs is working to understand how the brain circuitry controls how we move. The goal is to develop new technologies to help patients with Parkinson’s disease and other debilitating medical conditions navigate the world on their own. Their research is funded by the National Science Foundation’s Emerging Frontiers of Research and Innovation program.
"Parkinson’s disease is not just about one location in the brain that’s impaired. It’s the whole body. We look at the problems in a very holistic way, combine science and clinical aspects with engineering approaches for technology," explains Cauwenberghs, a professor at the Jacobs School of Engineering and co-director of the Institute for Neural Computation at UC San Diego. "We’re using advanced technology, but in a means that is more proactive in helping the brain to get around some of its problems—in this case, Parkinson’s disease—by working with the brain’s natural plasticity, in wiring connections between neurons in different ways."
Outcomes of this research are contributing to the system-level understanding of human-machine interactions, and motor learning and control in real world environments for humans, and are leading to the development of a new generation of wireless brain and body activity sensors and adaptive prosthetics devices. Besides advancing our knowledge of human-machine interactions and stimulating the engineering of new brain/body sensors and actuators, the work is directly influencing diverse areas in which humans are coupled with machines. These include brain-machine interfaces and telemanipulation.
Neural prosthesis restores behavior after brain injury
Scientists from Case Western Reserve University and University of Kansas Medical Center have restored behavior—in this case, the ability to reach through a narrow opening and grasp food—using a neural prosthesis in a rat model of brain injury.
Ultimately, the team hopes to develop a device that rapidly and substantially improves function after brain injury in humans. There is no such commercial treatment for the 1.5 million Americans, including soldiers in Afghanistan and Iraq, who suffer traumatic brain injuries (TBI), or the nearly 800,000 stroke victims who suffer weakness or paralysis in the United States, annually.
The prosthesis, called a brain-machine-brain interface, is a closed-loop microelectronic system. It records signals from one part of the brain, processes them in real time, and then bridges the injury by stimulating a second part of the brain that had lost connectivity.
Their work is published online this week in the science journal Proceedings of the National Academy of Sciences.
“If you use the device to couple activity from one part of the brain to another, is it possible to induce recovery from TBI? That’s the core of this investigation,” said Pedram Mohseni, professor of electrical engineering and computer science at Case Western Reserve, who built the brain prosthesis.
“We found that, yes, it is possible to use a closed-loop neural prosthesis to facilitate repair of a brain injury,” he said.
The researchers tested the prosthesis in a rat model of brain injury in the laboratory of Randolph J. Nudo, professor of molecular and integrative physiology at the University of Kansas. Nudo mapped the rat’s brain and developed the model in which anterior and posterior parts of the brain that control the rat’s forelimbs are disconnected.
Atop each animal’s head, the brain-machine-brain interface is a microchip on a circuit board smaller than a quarter connected to microelectrodes implanted in the two brain regions.
The device amplifies signals, which are called neural action potentials and produced by the neurons in the anterior of the brain. An algorithm separates these signals, recorded as brain spike activity, from noise and other artifacts. With each spike detected, the microchip sends a pulse of electric current to stimulate neurons in the posterior part of the brain, artificially connecting the two brain regions.
Two weeks after the prosthesis had been implanted and run continuously, the rat models using the full closed-loop system had recovered nearly all function lost due to injury, successfully retrieving a food pellet close to 70 percent of the time, or as well as normal, uninjured rats. Rat models that received random stimuli from the device retrieved less than half the pellets and those that received no stimuli retrieved about a quarter of them.
“A question still to be answered is must the implant be left in place for life?” Mohseni said. “Or can it be removed after two months or six months, if and when new connections have been formed in the brain?”
Brain studies have shown that, during periods of growth, neurons that regularly communicate with each other develop and solidify connections.
Mohseni and Nudo said they need more systematic studies to determine what happens in the brain that leads to restoration of function. They also want to determine if there is an optimal time window after injury in which they must implant the device in order to restore function.
(Source: blog.case.edu)
Neuroprosthesis gives rats the ability to ‘touch’ infrared light
Researchers have given rats the ability to “touch” infrared light, normally invisible to them, by fitting them with an infrared detector wired to microscopic electrodes implanted in the part of the mammalian brain that processes tactile information. The achievement represents the first time a brain-machine interface has augmented a sense in adult animals, said Duke University neurobiologist Miguel Nicolelis, who led the research team.
The experiment also demonstrated for the first time that a novel sensory input could be processed by a cortical region specialized in another sense without “hijacking” the function of this brain area said Nicolelis. This discovery suggests, for example, that a person whose visual cortex was damaged could regain sight through a neuroprosthesis implanted in another cortical region, he said.
Although the initial experiments tested only whether rats could detect infrared light, there seems no reason that these animals in the future could not be given full-fledged infrared vision, said Nicolelis. For that matter, cortical neuroprostheses could be developed to give animals or humans the ability to see in any region of the electromagnetic spectrum, or even magnetic fields. “We could create devices sensitive to any physical energy,” he said. “It could be magnetic fields, radio waves, or ultrasound. We chose infrared initially because it didn’t interfere with our electrophysiological recordings.”
Nicolelis and colleagues Eric Thomson and Rafael Carra published their findings February 12, 2013 in the online journal Nature Communications. Their research was sponsored by the National Institute of Mental Health.
Risk of childhood obesity can be predicted at birth
A simple formula can predict at birth a baby’s likelihood of becoming obese in childhood, according to a study published in the open access journal PLOS ONE.
The formula, which is available as an online calculator, estimates the child’s obesity risk based on its birth weight, the body mass index of the parents, the number of people in the household, the mother’s professional status and whether she smoked during pregnancy.
The researchers behind the study hope their prediction method will be used to identify infants at high risk and help families take steps to prevent their children from putting on too much weight.
Small genetic change has heavy consequences
One small change to the DNA sequence can cause more weighty changes to the human body, according to a new study released today. The discovery comes thanks to a worldwide consortium of researchers that includes Professor and Chair of Quantitative Genetics at The University of Queensland (UQ), Peter Visscher, from the Queensland Brain Institute (QBI) and Diamantina Institute (DI) at UQ.
He and his team have found a single change in genetic sequence at the gene FTO had a significant effect on the variability of body mass index (BMI). BMI is a commonly used measure of obesity. It measures someone’s weight adjusted for his or her height.
Professor Visscher said that the genetic change, called a single nucleotide polymorphism (SNP), was the replacement of one nucleotide – the units that make up our DNA – with another. “They are the most abundant type of variation in the human genome,” he said. “SNPs occur normally throughout our DNA and most have no effect on our health, however, we’ve found one that does have a small but significant effect on variation in BMI.”
After analysing data from almost 170,000 people, he and his team established that those with a sequence variant in the FTO gene not only weighed more on average, but the measured weights varied more than in the group without the variant. The variability of BMI within the group with two copies of the variant was, in fact, 7 per cent larger than the group without the variant.
Professor Visscher said this equated to around half a kilogram difference in the standard deviation of weight. “So as a group, people with two copies of the weight increasing variant are a few kilograms heavier and vary more,” he said. Genetic differences in variability of specific traits have been seen in many plant and animal species but specific genes or mechanisms to explain the phenomenon had not been identified.
Professor Visscher’s study is the first to look systematically at genetic effects on variation of a complex trait in humans using a very large sample size. “The study is important because it demonstrates that genes can be found that affect trait variability. “This is a first step towards understanding how genes control variation,” Professor Visscher said.
This study is also the first to offer researchers an indirect method to measure genotype by environment interactions without having a measure of specific environmental factors. “If a gene interacts with specific environmental factors then this can be observed with our method,” Professor Visscher said.
“For example, if the effect of a gene on weight is smaller in people who physically exercise than in people who do not, then this will lead to less variation among people with two copies of the weight decreasing variant.
“In our study we did not measure specific environmental effects such as physical exercise so we can’t say for sure whether our results are due to a genotype-environment interaction.”
This is the second study Professor Visscher has published in the prestigious journal Nature this year. Earlier this year he identified that genetic differences also affect how intelligence changes across a lifetime. The work also suggested these changes in intelligence were largely influenced by environmental factors.
(Source: uq.edu.au)
A new study by University of North Carolina School of Medicine pediatrics researchers finds a surprising difference in the eating habits of overweight children between ages 9 and 17 years compared to those younger than 9.
Younger children who are overweight or obese consume more calories per day than their healthy weight peers. But among older overweight children the pattern is reversed: They actually consume fewer calories per day than their healthy weight peers.
How to explain such a seemingly counterintuitive finding?
“Children who are overweight tend to remain overweight,” said Asheley Cockrell Skinner, PhD, assistant professor of pediatrics at UNC and lead author of the study published online Sept. 10, 2012 by the journal Pediatrics.
“So, for many children, obesity may begin by eating more in early childhood. Then as they get older, they continue to be obese without eating any more than their healthy weight peers,” Skinner said. “One reason this makes sense is because we know overweight children are less active than healthy weight kids. Additionally, this is in line with other research that obesity is not a simple matter of overweight people eating more — the body is complex in how it reacts to amount of food eaten and amount of activity.”
Snacking and BMI Linked to Double Effect of Brain Activity and Self-Control
ScienceDaily (July 23, 2012) — Snack consumption and BMI are linked to both brain activity and self-control, new research has found.
Snack consumption and BMI are linked to both brain activity and self-control, new research has found. (Credit: © farbkombinat / Fotolia)
The research, carried out by academics from the Universities of Exeter, Cardiff, Bristol, and Bangor, discovered that an individual’s brain ‘reward centre’ response to pictures of food predicted how much they subsequently ate. This had a greater effect on the amount they ate than their conscious feelings of hunger or how much they wanted the food,
A strong brain response was also associated with increased weight (BMI), but only in individuals reporting low levels of self-control on a questionnaire. For those reporting high levels of self-control a stronger brain response to food was actually related to a lower BMI.
This study, which is now published in the journal NeuroImage, adds to mounting evidence that overeating and increased weight are linked, in part, to a region of the brain associated with motivation and reward, called the nucleus accumbens. Responses in this brain region have been shown to predict weight gain in healthy weight and obese individuals, but only now have academics discovered that this is independent of conscious feelings of hunger, and that self-control also plays a key role.
Following these results, academics at the University of Exeter and Cardiff have begun testing ‘brain training’ techniques designed to reduce the influence of food cues on individuals who report low levels of self-control. Similar tests are being used to assist those with gambling or alcohol addiction.
Dr Natalia Lawrence of Psychology at the University of Exeter, lead researcher in both the original research and the new studies, said: “Our research suggests why some individuals are more likely to overeat and put on weight than others when confronted with frequent images of snacks and treats. Food images, such as those used in advertising, cause direct increases in activity in brain ‘reward areas’ in some individuals but not in others. If those sensitive individuals also struggle with self-control, which may be partly innate, they are more likely to be overweight. We are now developing computer programs that we hope will counteract the effects of this high sensitivity to food cues by training the brain to respond less positively to these cues.”
Twenty-five young, healthy females with BMIs ranging from 17-30 were involved in the study. Female participants were chosen because research shows females typically exhibit stronger responses to food-related cues. The hormonal changes during the menstrual cycle affect this reaction, so all participants were taking the monophasic combined oral contraceptive pill. Participants had not eaten for at least six hours to ensure they were hungry at the time of the scan and were given a bowl containing 150 g (four and a half packets) of potato chips to eat at the end of the study; they were informed that potato chip intake had been measured afterwards.
Researchers used MRI scanning to detect the participants’ brain activity while they were shown images of household objects, and food that varied in desirability and calorific content. After scanning, participants rated the food images for desirability and rated their levels of hunger and food craving. Results showed that participants’ brain responses to food (relative to objects) in the nucleus accumbens predicted how many potato chips they ate after the scan. However, participants’ own ratings of hunger and how much they liked and wanted the foods, including potato chips, were unrelated to their potato chip intake.
This study was funded by the Wales Institute of Cognitive Neuroscience.
What this study shows:
- Brain responses to food images vary considerably between individuals.
- Brain responses to food images but not conscious feelings of hunger or desire to eat predict subsequent potato chip consumption.
- Individuals’ reported levels of self-control influence whether this brain response is associated with a higher or lower BMI.
What this study does NOT show:
- Brain responses to food cues cause overeating.
- The associations reported here are true in everyone — only healthy young women were included.
- Whether our brain response and levels of self-control are learned or innate.
Source: Science Daily