10.15.08
Posted in Biology at the University of Virginia, Body Clock, Jacob Canon, Nocturnin, Sleep, The Oscar Show, UVa College of Arts & Sciences, University of Virginia, biology, circadian rhythms, metabolism, nervous system, neurophysiology, physical health, physiology, sensory inputs, stress, visual processing at 11:04 am by Jacob Canon
In today’s show, adapted from an article written by Fariss Samarrai, Senior News Officer for the Office of Public Affairs, we will look at a team of UVa researchers who have discovered a switching mechanism in the eye that plays a key role in regulating the sleep/wake cycles in mammals.
Biologists at the University of Virginia have discovered a switching mechanism in the eye that plays a key role in regulating the sleep/wake cycles in mammals. The new finding demonstrates that light receptor cells in the eye are central to setting the rhythms of the brain’s primary timekeeper, the suprachiasmatic nuclei, which regulates activity and rest cycles. The finding appears in the current issue of the Proceedings of the National Academy of Sciences.
Susan Doyle, a research scientist at U.Va. and the study’s lead investigator said, “The finding is significant because it changes our understanding of how light input from the eye can affect activity and sleep patterns.”
Eyeing the Biological Clock [4:46m]:
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Funded by the National Institute of Mental Health, Doyle conducted her research with colleagues Tomoko Yoshikawa, a visiting scholar from Japan, and UVa undergraduate student Holly Hillson, in the laboratory of Michael Menaker, a leading researcher in the study of circadian rhythms.
Biological clocks are the body’s complex network of internal oscillators that regulate daily activity/rest cycles and other important aspects of physiology, including body temperature, heart rate and food intake.
The investigators did this by both reducing the intensity of light given to normal mice and also creating a mutated line of mice with reduced light sensitivity in their eyes, which rendered them fully active in the day but inactive at night, a complete reversal of the normal activity/rest cycles of mice.
The researchers discovered that they could reverse the “temporal niche” of mice—meaning that the animals’ activity phase could be switched from their normal nocturnality, or night activity, to being diurnal, or day active.
Doyle said, “This suggests that we have discovered an additional mechanism for regulating nocturnity and diurnity that is located in the light input pathways of the eye. The significance of this research for humans is that it could ultimately lead to new treatments for sleep disorders, perhaps even eye drops that would target neural pathways to the brain’s central timekeeper.”
An estimated one in six people in the United States suffer from sleep disorders, including insomnia and excessive sleepiness. And as the U.S. population ages, a growing number of people are developing visual impairments that can result in sleep disorders.
Besides sleep disorders, research in this field may eventually help treat the negative effects of shift work, aging and jet lag. Doyle said, “Currently, one in 28 Americans age 40 and over suffer from blindness or low vision, and this number is estimated to double in the next 15 years. Our discovery of the switching mechanism in the eye has direct relevance with respect to the eventual development of therapies to treat circadian and sleep disorders in the visually impaired.”
You’ve been listening to the Oscar Show, I’m Jacob Canon. Join us next week when we look at the University of Virginia’s Kath Weston and the journey that led to her new book, Traveling Light: On the Road with America’s Poor.
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09.10.08
Posted in Engineering, Jacob Canon, The Oscar Show, UVa College of Arts & Sciences, University of Virginia, physical health, physiology, stress at 11:04 am by Jacob Canon
In today’s show, adapted from an article written for the U.Va. Engineer , the Alumni Magazine of the UVA School of Egineering and Applied Science, by freelance writer Charlie Feigenoff, we discuss the research of Silvia Salinas Blemker, an assistant professor of mechanical and aerospace engineering, who is trying to identify reasons and mechanics of hamstring pulls.
When the world’s best sprinters stepped up to the mark at the 100 meter final during this summer’s Olympic Games in Peking, they were moments away from subjecting their leg muscles to thousands of pounds of force as they fought to be first across the finish line less than 10 seconds later. By and large, their leg muscles handled the strain well, but inevitably one or more of these elite runners, despite intense conditioning, will suffer a hamstring pull during the track and field season.
Identifying Reasons for Hamstring Pulls [5:35m]:
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As Silvia Salinas Blemker, an assistant professor of mechanical and aerospace engineering at the University of Virginia’s School of Engineering and Applied Science has said, “Of all the muscles that work together when we run quickly, the muscles in the hamstring group are most subject to injury, and one particular hamstrings muscle, the biceps femoris long head, is most commonly injured.”
Blemker has the expertise in three-dimensional muscle modeling to find out why this muscle is so susceptible to pulls. Collaborating with Darryl Thelen, an associate professor of mechanical engineeering at the University of Wisconsin, she has embarked on a project to identify the points of strain as the biceps femoris moves dynamically and compare it to the other two hamstring muscles. Their research is supported by a four-year, $1.2 million grant from the National Institutes of Health.
The hamstrings run along the back of the thigh and attach on both sides of the knee joint. They are responsible for pulling the foot from the ground with each stride. In the past, researchers treated these muscles like anatomical rubber bands, uniformly elastic along their length.
Blemker said, “This simplistic view made it difficult to understand why one muscle is prone to injury while another isn’t.”
Blemker’s approach is more detailed. She has developed models that incorporate the muscle’s intricate internal geometry, which she is combining with a model of the whole-body dynamics of sprinting, developed by Thelen. By combining the model of the hamstrings with the framework provided by Thelen, Blemker will be able to predict how the muscle behaves in the course of real movement.
Blemker and Thelen face a number of challenges. The first is to merge these two models. Second, they then have to validate their new model by comparing predictions with MRI-imaging techniques that measure muscle strain distribution.
Blemker said, “Ultimately, we hope to learn how the internal structure of muscle changes when it is injured, which will help us suggest more effective rehabilitation strategies.”
As director of the U.Va. Multiscale Muscle Mechanics Laboratory, Blemker is also developing computational models that connect the properties of muscle fibers and the extracellular matrix that binds them together with the properties of the muscle as a whole. This line of research will help us understand how aging and diseases such as cerebral palsy and muscular dystrophy affect muscles.
Blemker’s work straddles several fields. She has appointments in biomedical engineering and orthopedic surgery as well as mechanical and aerospace engineering, but muscles have always been her focus. “I’ve been fascinated by the fact that muscles, which are so strong, are so easily injured,” she said. “Now I am finding out why.”
You’ve been listening to the Oscar Show, I’m Jacob Canon. Join us for our next show, when we will well discuss the research of a multi-institutional team of scientists, including Bob Hirosky, a University of Virginia associate professor of physics, and there attempt to verify or refute the existence of the Higgs boson, which is theorized to be the essence of all matter, and the ultimate basis of everything in the universe.
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02.06.08
Posted in Cognitive Science, Jacob Canon, The Oscar Show, UVa College of Arts & Sciences, Uncategorized, University of Virginia, nuerology, physical health, physiology, sensory inputs, technology, visual processing at 12:06 pm by Jacob Canon
In today’s show, adapted from an article published on the Oscar web site written by Linda Kobert, we examine the work of Dennis Proffitt, Professor and Director of the Cognitive Science Program, whose research focuses on creating computer interfaces to help make life more bearable for patients with ALS and other diseases that are the cause of locked-in syndrome.
Locked-In Syndrome [6:23m]:
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Up to now, the most iconic connection to Amyotrophic Lateral Sclerosis or Lou Gehrig’s disease, is the famous farewell in Yankee stadium By Mr. Gerhig. Forced to retire from baseball, the profession he loved and was best known for, he became the personification of this devastating disease.
In 2002, Peggy Chun, a popular artist was diagnosed with ALS. This debilitating neurological disorder progressively destroys a person’s motor neurons. As a victim of this incurable disease, Chun can feel, see, smell, taste, think and imagine, but she can no longer move in any way. She is, in the parlance of the medical profession, “locked-in.” ALS is the most frequent cause of locked-in syndrome, which begins with numbness in the extremities and progresses upward until all motor function disappears.
Usually the last thing you lose is eye movement,” says Dennis Proffitt, U.Va. cognitive psychologist and Commonwealth Professor of Psychology. “When you lose that, you are cognitively alert, you can think, you can feel, but you can’t move a thing. As a result, you can’t communicate in any way. It’s awful.”
Funded by the National Science Foundation, Proffitt, his colleagues at Georgia Tech and a company called Archinoetics in Hawaii are working to develop computer interfaces that may one day make life for locked-in patients more bearable.
Scientists know different parts of the brain are activated when a person performs different functions. For example, moving the left arm activates an area on the right side of the brain, the back of the brain is active with visual imagery and the frontal lobe is active when one tries to focus attention on something. Proffitt’s system simply detects whether or not a particular area of the brain is actively engaged at the time.
With this in mind, researchers are currently testing a technology that allows Chun and other locked-in patients to answer simple yes/no questions. An interface using functional near infrared imaging (fNIR) assesses activity in Broca’s area, a part of the brain where verbal working memory occurs. They strap a device, just above the left ear that projects a light beam through the skull measuring changes in blood volume and oxygenation when Broca’s area is engaged.
With the device in place, subjects are asked to count in their head when they want to activate the verbal working memory and initiate a “yes” response. When they want to say “no,” subjects think of clouds or rest or think “la la la.” It’s a process that most people can engage easily without having to spend a long time training to do it.
Proffitt said, “it was hard for us to think of something we could ask a person to do — something easy to control, something you can turn on and off — that we could measure in this way. What we came up with was sub-vocal speech … talking to yourself. You could be counting, or you could be reciting a poem. We couldn’t tell the difference. We have no idea what you’re doing. We just know the kind of thing you’re doing.”
He stresses, “It’s not reading your thoughts, we can’t do that.”
Proffitt admitted, “at this time the system is primitive, but it’s a start. Right now it’s an on/off switch. What we want to do is to get continuous control so the person is not just activating … Not just ‘yes’ or ‘no,’ but small to large, continuous control within some range. If we could achieve that in the next few years, that would be a huge improvement in what we will be able to do with the technology.”
For the half million people in the world with locked-in syndrome, having the ability to communicate, even in this primitive fashion, can make the difference between suffering in silence and a meaningful life.
But Peggy Chun isn’t waiting for the technology to evolve. This future icon of the human spirit refuses to be shut down. She uses the system now as a tool for creativity. With the sensor in place over her left ear, the artist activates Broca’s area to select shades from a palette that show up on a computer screen as horizontal gradations of color. She calls it “brain art,” and it may be simple, but it’s selling like hotcakes.
You’ve been listening to the Oscar Show, I’m Jacob Canon. Join us next week when our topic will be the research of Jared Harris, assistant professor at the University of Virginia’s Darden School of Business concerning business ethics and strategy, as he looks to answer the questions, “What motivates a company to cook the books? And, what happens to businesses that get caught committing financial fraud?”
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12.06.07
Posted in Biology at the University of Virginia, Gaesser, Jacob Canon, The Oscar Show, UVa College of Arts & Sciences, University of Virginia, biology, kinesiology, metabolism, physiology, stress at 1:10 pm by Jacob Canon
In today’s show we will discuss the research of UVa professor of exercise physiology Glenn Gaesser and his findings on what has come to be termed “BAD CARBS.”
With the holiday season upon us, traditional meals are a big part of the celebration. Meat, vegetables and breads are a big part of these feasts. Breads and other sources of carbohydrates have become a big concern for individuals worried about their weight and health. The latest common wisdom on carbohydrates claims that eating so-called “bad carbs” will make you fat. But University of Virginia professor Glenn Gaesser, professor of exercise physiology and director of the kinesiology program in the Curry School of Education says, “that’s just nonsense. Eating sandwiches with white bread, or an occasional doughnut, isn’t going to kill you, or necessarily even lead to obesity.”
A popular speaker, Gaesser has lectured on the subject of fitness, body weight and health at numerous national and international meetings and has appeared on dozens of radio and TV shows in North America. In an article in the October issue of the Journal of the American Dietetic Association, Gaesser analyzed peer-reviewed, scientific research on carbohydrate consumption, glycemic index and body weight. In this article he gives the first detailed review of the literature on the correlation between them. His findings run counter to the current consensus on the effects of “good” and “bad” carbs.
Gaesser, author of “It’s the Calories, Not the Carbs” and other books, found that diets high in carbohydrates are almost universally associated with slimmer bodies. More importantly, Gaesser found that consuming lots of high-glycemic foods is not associated with higher body weights. In fact, several large studies in the United States revealed that high-glycemic diets were linked to better weight control. “There is no reason to be eating fewer carbs — they’re not the enemy,” says Gaesser.
The description of carbohydrates as “good” or “bad” is based on glycemic index, a measure of the quality of the carbohydrate in terms of how much it raises blood sugar. Foods having a high GI are generally thought to be “bad” because they raise blood sugar more than “good” carbs do. Proponents of the glycemic index claim that this leads to excessive insulin secretion, which can cause weight gain and health problems. Foods such as whole-grain breads are said to offer “good” carbs, because they have a lower GI than white bread, for example. Likewise, a glass of pineapple juice has a high GI compared to apple juice. Several popular low-carb diets use glycemic index as a key feature for optimum weight control, but it is not a reliable description of carbohydrate quality, Gaesser says. Digestion is a complicated process. It’s very difficult to determine the GI of a whole meal, for instance, so it doesn’t really make sense to use GI or “glycemic load” — the glycemic index multiplied by the quantity ingested — as a guide to eating.
After looking at hundreds of articles on large-scale studies using surveys or randomized, controlled trials, Gaesser says they show that “people who consume high-carb diets tend to be slimmer, and often healthier, than people who consume low-carb diets.” Even high-glycemic foods have a place in the diet, he said, attributing that to the overall higher quality of a high-carb diet, which includes more fiber-rich and other nutritional foods.
Gaesser also looked for a clear association between carbohydrate consumption and illnesses, such as type 2 diabetes, heart disease and cancer. He found no compelling evidence that avoiding carbohydrates with a high GI helps prevent these diseases and others.Gaesser said, “People with diabetes, as well as very sedentary women who are obese, may benefit from lowering their consumption of foods with a high GI. Reducing any part of the diet — carbs, proteins or fats — will result in modest weight loss in the short term, if calorie consumption is reduced, he points out. But for long-term weight maintenance, a high-carb, low-fat diet is still the best bet.”
You’ve been listening to the Oscar Show… I’m Jacob Canon. Join us next week when our topic will be the research of UVa biology professor DeForest Mellon and his work concerning how the brain detects, integrates and uses co-joined yet dissimilar sensory inputs.
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11.22.07
Posted in Jacob Canon, James Coan, MRI, Psychology, Relationships, The Oscar Show, University of Virginia, anxiety, brain, emotions, environmental conditions, happiness, hypothalamus, immune, nervous system, neurobiology, neurophysiology, physical health, physiology, sensory inputs, stress at 3:46 pm by Jacob Canon
How did you react the last time you had a fight with that significant someone in your life? With couples, the woman might apologize, or the man might make a joke or express understanding. By doing this, they subtly and briefly lighten the tension as they work their way through a disagreement.
Psychology Professor James Coan discovered a long time ago that by doing this, even when couples fight, they take care of each other. This interplay was significant when Coan designed a study exploring what happens in people’s brains when they behave emotionally or observe other people’s emotions. Coan said, “what we are learning is our emotions are more heavily involved in our day-to-day physical health than we previously thought.
How we deal with our relationships is closely tied to how long we live, how frequently we go to the doctor, how rapidly we recover from injury, how happy we tend to be in our lives.” With his colleagues, Hillary Schaefer and Richard J. Davidson from the University of Wisconsin, Coan sought to demonstrate the neurobiological basis of emotional expression and regulatory processes.
In the study, they used MRI technology to view these responses at the level of glucose metabolism and blood oxygenation in the brain. Because of the importance of emotional connectedness to the study, 16 happily married, heterosexual couples were recruited as test subjects. Wives were placed in the scanner so brain activity could be recorded as each was exposed to the anxiety-producing possibility of an electric shock to the ankle.
Researchers wanted to see what effect different types of emotional support would have in areas of the brain related to the body’s normal fight-or-flight stress response. Readings were taken when the woman was alone in facing this challenge, When a stranger, a male, was present to support her And when her husband offered support. Coan stated, “the scanning environment is pretty hostile to looking at interactions between people.” The MRI machine surrounds the subject’s body and restricts movement. The women weren’t even able to see the support person during the scanning process.
Having the man offer his hand for the woman to hold was about the only intervention possible in this setting. Not surprisingly, the results show there was a healthy reduction in the stress response when test subjects were supported. Stimulation in the regions of the brain that regulate physiological arousal and coordinate large muscles and joints was significantly decreased, no matter who was holding the woman’s hand. However, when it was her husband’s hand she was holding, the response was significantly greater.
Coan said, “When you’re holding a spouse’s hand, you get down-regulation in all of those same systems. But all the other systems that have to do with the conscious regulation of your emotions — having to pay attention to what’s happening with your body and having to become more vigilant for future dangers — all of these other systems come down as well. Your brain doesn’t work as hard when it’s your spouse. What surprised Coan and his colleagues most was the relaxation response demonstrated by what they called “super couples.” In those couples with exceptionally high-quality relationships, “Hand-holding had a significantly greater effect on soothing their brains.”
Tests showed differences involving two structures that were not affected at all in other test subjects. They observed evidence of reduced release of stress hormones by the hypothalamus. These hormones are responsible for inhibiting immune response and other activities that have critical implications for health and well-being.
Of greater interest was the reduction of activity in the right anterior insula. This brain structure modulates the amount of pain stimulus one experiences subjectively. Reduction of activity in this area means test subjects actually felt less pain when they held their husband’s hand.
So it can be said, having someone you love hold your hand really can take the hurt away.
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