Just Pretend Those Carrots Are Cheese Fries

The problem with your diet is not that you’ve been eating the wrong food, but rather you’ve been thinking about your food all wrong.  According to Alia Crum, a clinical psychology researcher at Yale University, our mind’s opinion of food labeled or thought of to be “diet” or “low fat” can actually affect our body’s physiological response after eating it, which changes our metabolism.  

Her sneaky research team told 46 volunteers that they were getting two milkshakes to drink.  In the first test, they were told they were sampling a “health” shake that had no fat, no added sugar and a skinny 140 calories.  At a separate test, the same group were told they were rewarded with an “indulgent” shake weighing in at a guilt-inducing 620 calories and full of fat.

The trick was that in each test, the milkshakes were actually identical with each having 360 calories.  Only the description and labelling of the shakes were different.

At this point, Crum and her less than honest team could have just asked the volunteers which shake made them “feel fuller.”  Instead, they chose to measure satiety by observing changes in the level of ghrelin, the so-called “hunger hormone” in the stomach that signals the brain when to eat and when to stop eating.  When you’re hungry, your level of ghrelin goes up, telling your brain to find some snacks.  After a meal, your ghrelin goes down trying to convince you not to go back for a third helping.

Blood tests were gathered from the drinkers before, during and after the shakes to measure their ghrelin.  

Results showed that when the participants drank the “health” shake, their ghrelin levels stayed about the same or slightly increased.  However, after drinking the “indulgent” shake, their ghrelin levels dropped significantly.  In other words, their perception of what they were eating tricked their body into responding differently. Same shake, different physiological responses.

The study was published last month in the journal Health Psychology.

So, let’s put this in the real world.  You’re trying to lose weight by eating “healthy” foods, with lower calories and fat.  But, you’ve also been conditioned to think that these foods just don’t satisfy your hunger like a greasy cheeseburger would.  Eating 500 calories of fruits and vegetables doesn’t feel as good as eating 500 calories of french fries.  

"What was most interesting," Crum said, "is that the results were somewhat counter-intuitive. Consuming the shake thinking it was ‘indulgent' was healthier than thinking it was ‘sensible.' It led to a sharper reduction in ghrelin." By drinking the “indulgent” shake, you actually might eat less after that since your lower ghrelin levels would dampen the hunger signal to your brain.

"I think the most important message from this study is for consumers to be aware of the mind-set that they are in while they are eating, and especially the mind-set that individuals seem to automatically adopt when trying to maintain or lose weight," writes Crum.. "The mind-set of 'sensibility' or 'restraint'—no matter what we're eating—might be compromising our body's physiological response, counteracting our hard work at dieting. People should still work to eat healthy, but do so in a mind-set of indulgence."

Tricking the brain is not new to Crum.  In 2007, she assisted psychologist Ellen Langer in a groundbreaking mindfulness study that convinced New York City hotel maids that the daily work they performed was enough to improve their health.  They interviewed 84 maids on their daily exercise habits outside of work.  Most said they barely worked out at all.  

Then, they educated half the group on how their daily work of changing beds, vacuuming, etc. was actually good exercise.  After one month, they reported that the educated group’s blood pressure had dropped by 10% without any additional work or exercise.  Langer and Crum claim the placebo effect had changed the women’s health, just by the perception that they were exercising.  The study had its critics, but it was an interesting finding nonetheless.

So, while a Big Mac is still bad for you, it may actually convince you to eat less that day then trying to fool your brain into thinking your bag of carrots is actually a bag of cheese fries.

You might also like: Exercise Burns Fat During But Not After Your Workout and New Proof That Exercise Pumps Up Your Metabolism

If Your Brain Is Over 40, It Needs To Move

There was a time when I could hide my gray hairs with some strategic combing.  Now, I have succumbed and describe my new hair color as “executive blond.”  Of course, that also means that the important stuff under my scalp is getting older too.  Brains start to “go gray” about the same time the hair does, which is why exercise for older adults has become the new anti-aging fix for our senior cerebellums. Several new studies provide more evidence that a brain in motion tends to remain... young.

The older population (which does not include me yet!), persons 65 years or older, totaled 39.6 million in 2009 (the latest year for which data is available). They represented 12.9% of the U.S. population, about one in every eight Americans. By 2030, there will be about 72.1 million older persons, more than twice their number in 2000. People 65+ represented 12.4% of the population in the year 2000 but are expected to grow to be 19% of the population by 2030.

Over the last several years, dozens of studies have concluded that exercise helps not only your reflection in the mirror but also your cognitive ability.  Just in the last four months, three research projects, one small, one medium and one large, reported their findings of the effects of exercise on the older brain.

First up, a micro study of 16 women, aged 60 and over, hypothesized that a moderate exercise program would increase blood flow to the brain.  Dr. Rong Zhang, a researcher at the Institute for Exercise and Environmental Medicine at Texas Health Presbyterian Hospital Dallas, first measured the blood flow in the women's internal carotid arteries, using Doppler ultrasonography.  Next, a baseline test was taken of their maximal oxygen consumption (VO2 max) to gauge their body’s ability to use oxygen during exercise.

Then the walking started.  Each woman was given a training plan based on their current fitness level that started with three 30-minute sessions per week of walking at a pace of 50-60% of their VO2 maximum.  By the third month, this was increased to four sessions at 70-80% of VO2 max.

A second blood flow test showed a significant increase in cerebral blood flow by an average of 15% in the women’s left carotid artery and 11% in the right artery.  VO2 max also went up by 13%, while their blood pressures and heart rates declined by 4% and 5%, respectively.

Dr. Zhang likes the correlation, "There are many studies that suggest that exercise improves brain function in older adults, but we don't know exactly why the brain improves. Our study indicates it might be tied to an improvement in the supply of blood flow to the brain."

So, what might that extra blood be doing for the brain?  Kirk Erickson, professor of psychology at the University of Pittsburgh, is convinced that exercise actually grows the size of the brain.  He and a cross-university team of scientists recruited 120 dementia-free, sedentary senior citizens to measure their brain size before and after a one year long walking program.  After measuring each volunteers’ hippocampus dimensions using magnetic resonance imaging (MRI), they were split into two groups.  One group would start a walking program of 40 minutes per session, three days per week, while the other group simply did a stretching and toning program.

After one year, a second MRI showed that the walkers increased their hippocampus size by an average of 2% while those that only stretched showed a decrease in brain volume of about 1.4%.  Also, a spatial memory test performed pre and post exercise showed a significant improvement for the walkers versus the stretchers.

"We think of the atrophy of the hippocampus in later life as almost inevitable," said Kirk Erickson, professor of psychology at the University of Pittsburgh and the paper's lead author. "But we've shown that even moderate exercise for one year can increase the size of that structure. The brain at that stage remains modifiable."

There is another important benefit to that extra blood flow, preventing strokes or even small brain lesions, or infarcts, often known as silent strokes.  "These 'silent strokes' are more significant than the name implies, because they have been associated with an increased risk of falls and impaired mobility, memory problems and even dementia, as well as stroke," said brain researcher Joshua Z. Willey, MD of Columbia University in New York.

Willey and his team asked 1,238 people over age 60, who had never had a stroke, about the frequency and intensity of their exercise regimen.  About 43 percent of the participants reported that they had no regular exercise; 36 percent did regular light exercise, such as golf, walking, bowling or dancing; and 21 percent performed regular moderate to intense exercise, such as hiking, tennis, swimming, biking, jogging or racquetball.

Six years later, all participants underwent an MRI scan of their brain.  Sixteen percent of the group, 197 volunteers, had suffered from an infarct or silent stroke during the time frame.  However, the moderate to intense exercise group was 40% less likely to have had the small lesions than the group that did not exercise at all.  There was no significant difference between those that did light exercise and those that did no exercise.

"Encouraging older people to take part in moderate to intense exercise may be an important strategy for keeping their brains healthy,” concluded Willey. "Of course, light exercise has many other beneficial effects, and these results should not discourage people from doing light exercise."

So, no excuses anymore.  Throw some hair color on your scalp, then go for that walk.  Your hair will look young and your brain will think young.


See also: Exercise Pumps Up Your Brain and Boomer Brains Need Exercise

Exercise Helps Older Brains - Now We Know Why

Research conducted at Texas Health Presbyterian Hospital's Institute for Exercise and Environmental Medicine in Dallas suggests that it's never too late for women to reap the benefits of moderate aerobic exercise. In a 3-month study of 16 women age 60 and older, brisk walking for 30-50 minutes three or four times per week improved blood flow through to the brain as much as 15%.

Rong Zhang, the lead researcher in the study, discussed the team's findings in a presentation titled, "Aerobic exercise training increases brain perfusion in elderly women" at the Experimental Biology meeting (EB 2011), held April 9-13, 2011 at the Walter E. Washington Convention Center, Washington, DC.

At the beginning of the study, the researchers used Doppler ultrasonography to measure blood flow in the women's internal carotid arteries, which are located in the neck and supply the brain with necessary glucose and oxygen-rich blood. After assessing the women's physical health and maximal oxygen consumption (VO2 max), which is the body's maximum capacity to transport and use oxygen during exercise, the team tailored training programs for each woman according to her fitness level.

Training started at a base pace of 50-60% of the participants' VO2 max for 30 minutes per session, three times per week. By the third month, the team had increased the sessions to 50 minutes each, four times per week, and added two more sessions at 70-80% of the women's VO2 max for 30 minutes.

At study's end, the team measured blood flow in the women's carotid arteries again and found that cerebral blood flow increased an average of 15% and 11% in the women's left and right internal carotid arteries, respectively. The women's VO2 max increased roughly 13%, their blood pressure dropped an average of 4%, and their heart rates decreased approximately 5%.

According to Dr. Zhang, the results provide insight into how vascular health affects brain health. "There are many studies that suggest that exercise improves brain function in older adults, but we don't know exactly why the brain improves. Our study indicates it might be tied to an improvement in the supply of blood flow to the brain."

A steady, healthy flow of blood to the brain achieves two things. First, the blood brings oxygen, glucose and other nutrients to the brain, which are vital for the brain's health. Second, the blood washes away brain metabolic wastes such as amyloid-beta protein released into the brain's blood vessels. Amyloid-beta protein has been implicated in the development of Alzheimer's disease.

Whether the increased blood flow to the brain improves learning and reasoning has yet to be determined, says Dr. Zhang. "I don't have the data to suggest a correlation between brain perfusion and cognitive function, but this is something we eventually will see after this study is completed," he says. "We do know there is strong evidence to suggest that cardiovascular risk is tied to the risk for Alzheimer's disease. We want to see how we can fight that."

Dr. Zhang stresses the importance of the finding that improvement in brain blood flow is possible in one's senior years. "We often start to see a decline in brain perfusion and cognitive function in the 60s and 70s. That's when the downward trajectory starts. We want to see how much we can do to reverse or delay that process."

Source:  American Physiological Society

You'll Also Like: Exercise Grows Kids' Brains, Literally and Exercise Pumps Up Your Brain

Exercise Grows Kids' Brains, Literally

Researchers have found an association between physical fitness and the brain in 9- and 10-year-old children: Those who are more fit tend to have a bigger hippocampus and perform better on a test of memory than their less-fit peers.  The new study, which used magnetic resonance imaging to measure the relative size of specific structures in the brains of 49 child subjects, appears in the journal Brain Research.

"This is the first study I know of that has used MRI measures to look at differences in brain between kids who are fit and kids who aren't fit," said University of Illinois psychology professor and Beckman Institute director Art Kramer, who led the study with doctoral student Laura Chaddock and kinesiology and community health professor Charles Hillman. "Beyond that, it relates those measures of brain structure to cognition."

The study focused on the hippocampus, a structure tucked deep in the brain, because it is known to be important in learning and memory. Previous studies in older adults and in animals have shown that exercise can increase the size of the hippocampus. A bigger hippocampus is associated with better performance on spatial reasoning and other cognitive tasks.

"In animal studies, exercise has been shown to specifically affect the hippocampus, significantly increasing the growth of new neurons and cell survival, enhancing memory and learning, and increasing molecules that are involved in the plasticity of the brain," Chaddock said.

Rather than relying on second-hand reports of children's physical activity level, the researchers measured how efficiently the subjects used oxygen while running on a treadmill.

"This is the gold standard measure of fitness," Chaddock said.

The physically fit children were "much more efficient than the less-fit children at utilizing oxygen," Kramer said.  When they analyzed the MRI data, the researchers found that the physically fit children tended to have bigger hippocampal volume -- about 12 percent bigger relative to total brain size -- than their out-of-shape peers.

The children who were in better physical condition also did better on tests of relational memory -- the ability to remember and integrate various types of information -- than their less-fit peers.

"Higher fit children had higher performance on the relational memory task, higher fit children had larger hippocampal volumes, and in general, children with larger hippocampal volumes had better relational memory," Chaddock said.

Further analyses indicated that a bigger hippocampus boosted performance on the relational memory task.

"If you remove hippocampal volume from the equation," Chaddock said, "the relationship between fitness and memory decreases."

The new findings suggest that interventions to increase childhood physical activity could have an important effect on brain development.  "We knew that experience and environmental factors and socioeconomic status all impact brain development," Kramer said. "If you get some lousy genes from your parents, you can't really fix that, and it's not easy to do something about your economic status. But here's something that we can do something about."

Source: University of Illinois at Urbana-Champaign and A neuroimaging investigation of the association between aerobic fitness, hippocampal volume and memory performance in preadolescent children. Brain Research, 2010; DOI: 10.1016/j.brainres.2010.08.049

See also: Fit Kids Get Better Grades and For Kids' Health, Just Let Them Play

Exercise Pumps Up Your Brain

Regular exercise speeds learning and improves blood flow to the brain, according to a new study led by researchers from the University of Pittsburgh School of Medicine that is the first to examine these relationships in a non-human primate model. The findings are available in the journal Neuroscience.

While there is ample evidence of the beneficial effects of exercise on cognition in other animal models, such as the rat, it has been unclear whether the same holds true for people, said senior author Judy L. Cameron, Ph.D., a psychiatry professor at Pitt School of Medicine and a senior scientist at the Oregon National Primate Research Center at Oregon Health and Science University. Testing the hypothesis in monkeys can provide information that is more comparable to human physiology.

"We found that monkeys who exercised regularly at an intensity that would improve fitness in middle-aged people learned to do tests of cognitive function faster and had greater blood volume in the brain's motor cortex than their sedentary counterparts," Dr. Cameron said. "This suggests people who exercise are getting similar benefits."

For the study, the researchers trained adult female cynomolgus monkeys to run on a human-sized treadmill at 80 percent of their individual maximal aerobic capacity for one hour each day, five days per week, for five months. Another group of monkeys remained sedentary, meaning they sat on the immobile treadmill, for a comparable time. Half of the runners went through a three-month sedentary period after the exercise period. In all groups, half of the monkeys were middle aged (10 to 12 years old) and the others were more mature (15 to 17 years old). Initially, the middle-aged monkeys were in better shape than their older counterparts, but with exercise, all the runners became more fit.


During the fifth week of exercise training, standardized cognitive testing was initiated and then performed five days per week until week 24. In a preliminary task, the monkeys learned that by lifting a cover off a small well in the testing tray, they could have the food reward that lay within it. In a spatial delay task, a researcher placed a food reward in one of two wells and covered both wells in full view of the monkey. A screen was lowered to block the animal's view for a second, and then raised again. If the monkey displaced the correct cover, she got the treat. After reliably succeeding at this task, monkeys that correctly moved the designated one of two different objects placed over side-by-side wells got the food reward that lay within it.

"Monkeys that exercised learned to remove the well covers twice as quickly as control animals," Dr. Cameron said. "Also, they were more engaged in the tasks and made more attempts to get the rewards, but they also made more mistakes."

She noted that later in the testing period, learning rate and performance was similar among the groups, which could mean that practice at the task will eventually overshadow the impact of exercise on cognitive function.

When the researchers examined tissue samples from the brain's motor cortex, they found that mature monkeys that ran had greater vascular volume than middle-aged runners or sedentary animals. But those blood flow changes reversed in monkeys that were sedentary after exercising for five months.

"These findings indicate that aerobic exercise at the recommended levels can have meaningful, beneficial effects on the brain," Dr. Cameron said. "It supports the notion that working out is good for people in many, many ways."

Source: University of Pittsburgh Schools of the Health Sciences.

See also: Take Your Brain To The Gym and Boomer Brains Need Exercise

Aerobic Fitness Helps Brains of Multiple Sclerosis Patients

Highly fit multiple sclerosis patients perform significantly better on tests of cognitive function than similar less-fit patients, a new study shows.  In addition, MRI scans of the patients showed that the fitter MS patients showed less damage in parts of the brain that show deterioration as a result of MS, as well as a greater volume of vital gray matter.

"We found that aerobic fitness has a protective effect on parts of the brain that are most affected by multiple sclerosis," said Ruchika Shaurya Prakash, lead author of the study and assistant professor of psychology at Ohio State University.  "As a result, these fitter patients actually show better performance on tasks that measure processing speed."

The study, done with colleagues Robert Motl and Arthur Kramer of the University of Illinois and Erin Snook of the University of Massachusetts, Amherst, appears online in the journal Brain Research and will be published in a future print edition.


The study involved 21 women diagnosed with relapsing-remitting MS. They were compared with 15 age- and education-matched healthy female controls. The study assessed fitness, cognitive function, and structural changes in all participants.  In order to measure fitness levels, the participants underwent a VO2 max test, in which they rode a stationary bicycle until they felt exhausted. During the test, they breathed into a mask which measured their oxygen consumption.

All the women also took a variety of tests designed to evaluate cognitive functions, such as processing speed and selective attention. In one test, for example, participants had to write down in one minute as many words as they could think of that began with the letter "F." MS patients generally perform poorly on these tests compared to healthy people.  The third analysis involved MRIs of the participants, revealing any damage to their brains.

As expected, the MS patients did much worse than the healthy controls on the tests of brain functioning, and showed more deterioration in their brains as revealed through the MRIs.  But what was interesting, Prakash said, was the significant differences between the more aerobically fit MS patients and those who were less fit.

Take, for instance, lesions, which are the characteristic feature of MS. Lesions are areas of inflammation in the central nervous system in which neurons have been stripped of myelin, an insulating protein.

"Physically fit MS patients had fewer lesions compared to those who weren't as fit and the lesions they did have tended to be smaller," Prakash said. "This is significant and can help explain why the higher-fit patients did better on tests of brain functioning."

Aerobic fitness was also associated with less-damaged brain tissue in MS patients, both the gray matter and white matter.  Gray matter is the cell bodies in the brain tissue, while white matter is the fibers that connect the various gray matter areas.

The study found that fitness in MS patients was associated with larger volume of gray matter, accounting for about 20 percent of the volume in gray matter. That's important, Prakash said, because gray matter is linked to brain processing skills.

"Even in gray matter that appeared relatively healthy, we found a deterioration in the volume in MS patients," she said. "But for some of the highest fit MS patients, we found that their gray matter volume was nearly equivalent to that of healthy controls."

Another MRI analysis involved the integrity of the white matter in the brain. In MS patients, the white matter deteriorates as the myelin is stripped from neurons. Again, higher-fit MS patients showed less deterioration of white matter compared to those who were less fit.

Overall, the three MRI tests in this study showed that parts of the brain involved in processing speed are all negatively affected by MS -- but less so in patients who are aerobically fit.

Prakash noted that other researchers have found that exercise promotes the production of nerve growth factors, proteins which are important for the growth and maintenance of neurs in the brain.  "Our hypothesis is that aerobic exercise enhances these nerve growth factors in MS patients, which increases the volume of the gray matter and increases the integrity of the white matter," she said.  "As a result there is an improvement in cognitive function."

Prakash and her colleagues plan to extend this research by studying whether exercise interventions with MS patients can actually improve their cognition and have positive physical effects on the brain.

"For a long time, MS patients were told not to exercise because there was a fear it could exacerbate their symptoms," she said.  "But we're finding that if MS patients exercise in a controlled setting, it can actually help them with their cognitive function."

The research was supported by a grant from the National Institute on Aging.

Source: Ohio State University
See also: Take Your Brain To The Gym,  Boomer Brains Need Exercise and Exercise May Help Schizophrenia Patients

Exercise May Help Schizophrenia Patients

Potentially beneficial brain changes (an increase in the volume of an area known as the hippocampus) occur in response to exercise both in patients with schizophrenia and healthy controls, according to a report in the February issue of Archives of General Psychiatry, one of the JAMA/Archives journals. The findings suggest that the brain retains some plasticity, or ability to adapt, even in those with psychotic disorders.

Schizophrenia is known to be associated with a reduced volume in the area of the brain known as the hippocampus, which helps regulate emotion and memory, according to background information in the article. "In contrast to other illnesses that may display psychotic features, such as bipolar disorder, schizophrenia is often characterized by incomplete recovery of psychotic symptoms and persistent disability," the authors write. "These clinical features of illness may relate to an impairment of neural plasticity or mechanisms of reorganizing brain function in response to a challenge."

The formation of new neurons is one component of plasticity; previous studies have shown that neuron growth in the hippocampus of healthy individuals can be stimulated by exercise. Frank-Gerald Pajonk, M.D., of The Saarland University Hospital, Homburg, and Dr. K. Fontheim's Hospital for Mental Health, Liebenburg, Germany, and colleagues assessed changes in hippocampal volume in response to an exercise program in both male patients with schizophrenia and men who had similar demographics and physical characteristics but did not have the condition.

Eight participants with schizophrenia and eight controls were randomly assigned to exercise (supervised cycling) three times per week for 30 minutes, whereas an additional eight patients with schizophrenia instead played tabletop football for the same period of time. The game enhances coordination and concentration but does not affect aerobic fitness. All participants underwent fitness testing, magnetic resonance imaging of the hippocampus, neuropsychological testing and other clinical measures before and after participating in the program for 12 weeks.

Following exercise training, hippocampal volume increased 12 percent in patients with schizophrenia and 16 percent in healthy controls. "To provide a context, the magnitude of these changes in volume was similar to that observed for other subcortical structures when patients were switched from typical to atypical antipsychotic drug therapy," the authors write. Conversely, patients with schizophrenia who played tabletop football instead of exercising experienced a 1 percent decrease in hippocampal volume.

Aerobic fitness also increased among all who exercised, and improvement in test scores for short-term memory was correlated with increases in hippocampal volume among patients and healthy controls.
"Further clinical studies are needed to determine if an incremental improvement in the disability related to schizophrenia could be obtained by incorporating exercise into treatment planning and lifestyle choice for individuals with the illness," the authors conclude.

Sources:  JAMA and Archives Journals  and  Hippocampal Plasticity in Response to Exercise in Schizophrenia

Stroke Patients Benefit From New Brain And Motor Skills Research

Bioengineers have taken a small step toward improving physical recovery in stroke patients by showing that a key feature of how limb motion is encoded in the nervous system plays a crucial role in how new motor skills are learned.

Published in a recent issue of Neuron, a Harvard-based study about the neural learning elements responsible for motor learning may help scientists design rehabilitation protocols in which motor adaptation occurs more readily, potentially allowing for a more rapid recovery.

Neuroscientists have long understood that the brain's primary motor cortex and the body's low-level peripheral stretch sensors encode information about the position and velocity of limb motion in a positively-correlated manner rather than as independent variables.

"While this correlation between the brain's encoding of the position and the velocity of motion is well-known, its potential importance and practical use has been unclear until now," says coauthor Maurice A. Smith, Assistant Professor of Bioengineering at the Harvard School of Engineering and Applied Sciences (SEAS) and the Center for Brain Science in the Faculty of Arts and Sciences.

Smith and colleagues showed that the correlated neural tuning to position and velocity is also present in the neural learning elements responsible for motor learning. Moreover, this correlated drive can explain key features of the motor adaptation process.

To study and record motor adaptation, the researchers had subjects grasp a robotic arm. The device was programmed to simulate novel physical dynamics as subjects made reaching motions. In addition, the team used a newly developed measurement technique called an "error-clamp" to tease apart the resulting data.

The method measures motor output during learning, allowing learning-related changes in motor output over the course of a movement to be dissociated from feedback adjustments that correct motor errors that happen simultaneously.

"Conceptually, this error-clamp is analogous to a voltage-clamp, commonly used in electrophysiology to measure how ions move through a neuron's membrane when it fires," explains lead author Gary C. Sing, a graduate student at SEAS. "The general idea is that devising an experimental method to clamp and control the key variable in an experiment can allow for greater insight into the underlying physiology."

Analysis of the data extracted by the error-clamp technique led to the creation of a computational model that identifies a set of vectors that characterize the principal components of motor adaptation in the state space of physical motion. While such analysis is commonplace in systems engineering -- for example, in evaluating how a bridge might react to high winds or earthquakes -- the method has only been recently applied to how motor output evolves.

"We observed that the initial stages of motor learning are often quick but non-specific, whereas later stages of learning are slower and more precise," says Sing. "Further, we saw that some physical patterns of movement are learned more quickly than others."

By understanding what types of motor adaptations are easier to learn, the researchers hope to design rehabilitation activities that will encourage patients to use an affected limb more.

"In stroke rehabilitation, patients who make a greater effort to use their impaired limbs can achieve better outcomes," says Smith. "However, there is often a vicious cycle, as a patient is far less likely to use an impaired limb if his or her other limb is fine. This pattern slows recovery and leads to greater impairment of the affected limb."

Smith and his colleagues are beginning studies with stroke patients to determine whether training them with such optimized patterns will, in fact, improve their rate of motor learning and speed up recovery.
More broadly, untangling the algorithms the brain uses for motor learning could help improve a wide range of neural and muscular rehabilitation programs. The researchers also anticipate that such findings could be one day be adapted for enhancing the brain/machine interfaces increasingly used for those with amputated limbs.

Sources:  Harvard University and "Primitives for Motor Adaptation Reflect Correlated Neural Tuning to Position and Velocity"

Boomer Brains Need Exercise

Moderate physical activity performed in midlife or later appears to be associated with a reduced risk of mild cognitive impairment, whereas a six-month high-intensity aerobic exercise program may improve cognitive function in individuals who already have the condition, according to two reports in the January issue of Archives of Neurology.

Mild cognitive impairment is an intermediate state between the normal thinking, learning and memory changes that occur with age and dementia, according to background information in one of the articles. Each year, 10 percent to 15 percent of individuals with mild cognitive impairment will develop dementia, as compared with 1 percent to 2 percent of the general population. Previous studies in animals and humans have suggested that exercise may improve cognitive function.

In one article, Laura D. Baker, Ph.D., of the University of Washington and Veterans Affairs Puget Sound Health Care System, Seattle, and colleagues report the results of a randomized, controlled clinical trial involving 33 adults with mild cognitive impairment (17 women, average age 70). A group of 23 were randomly assigned to an aerobic exercise group and exercised at high intensity levels under the supervision of a trainer for 45 to 60 minutes per day, four days per week. The control group of 10 individuals performed supervised stretching exercises according to the same schedule but kept their heart rate low. Fitness testing, body fat analysis, blood tests of metabolic markers and cognitive functions were assessed before, during and after the six-month trial.

A total of 29 participants completed the study. Overall, the patients in the high-intensity aerobic exercise group experienced improved cognitive function compared with those in the control group. These effects were more pronounced in women than in men, despite similar increases in fitness. The sex differences may be related to the metabolic effects of exercise, as changes to the body's use and production of insulin, glucose and the stress hormone cortisol differed in men and women.

"Aerobic exercise is a cost-effective practice that is associated with numerous physical benefits. The results of this study suggest that exercise also provides a cognitive benefit for some adults with mild cognitive impairment," the authors conclude. "Six months of a behavioral intervention involving regular intervals of increased heart rate was sufficient to improve cognitive performance for an at-risk group without the cost and adverse effects associated with most pharmaceutical therapies."

In another report, Yonas E. Geda, M.D., M.Sc., and colleagues at Mayo Clinic, Rochester, Minn., studied 1,324 individuals without dementia who were part of the Mayo Clinic Study of Aging. Participants completed a physical exercise questionnaire between 2006 and 2008. They were then assessed by an expert consensus panel, who classified each as having normal cognition or mild cognitive impairment.

A total of 198 participants (median or midpoint age, 83 years) were determined to have mild cognitive impairment and 1,126 (median age 80) had normal cognition. Those who reported performing moderate exercise—such as brisk walking, aerobics, yoga, strength training or swimming—during midlife or late life were less likely to have mild cognitive impairment. Midlife moderate exercise was associated with 39 percent reduction in the odds of developing the condition, and moderate exercise in late life was associated with a 32 percent reduction. The findings were consistent among men and women.

Light exercise (such as bowling, slow dancing or golfing with a cart) or vigorous exercise (including jogging, skiing and racquetball) were not independently associated with reduced risk for mild cognitive impairment.

Physical exercise may protect against mild cognitive impairment via the production of nerve-protecting compounds, greater blood flow to the brain, improved development and survival of neurons and the decreased risk of heart and blood vessel diseases, the authors note. "A second possibility is that physical exercise may be a marker for a healthy lifestyle," they write. "A subject who engages in regular physical exercise may also show the same type of discipline in dietary habits, accident prevention, adherence to preventive intervention, compliance with medical care and similar health-promoting behaviors."

Future study is needed to confirm whether exercise is associated with the decreased risk of mild cognitive impairment and provide additional information on cause and effect relationships, they conclude.

Sources:  JAMA and Archives Journals, Physical Exercise, Aging, and Mild Cognitive Impairment: A Population-Based Study  and Effects of Aerobic Exercise on Mild Cognitive Impairment: A Controlled Trial.

Running Addicts Need Their Fix

Just as there is the endorphin rush of a "runner's high," there can also be the valley of despair when something prevents avid runners from getting their daily fix of miles.

Now, researchers at Tufts University may have confirmed this addiction by showing that an intense running regimen in rats can release brain chemicals that mimic the same sense of euphoria as opiate use. They propose that moderate exercise could be a "substitute drug" for human heroin and morphine addicts.

Given all of the benefits of exercise, many people commit to an active running routine. Somewhere during a longer, more intense run when stored glycogen is depleted, the pituitary gland and the hypothalamus release endorphins that can provide that "second wind" that keeps a runner going.

This sense of being able to run all day is similar to the pain-relieving state that opiates provide, scientists have known. So a team led by Robin Kanarek, professor of psychology at Tufts University, wondered whether they could also produce similar withdrawal symptoms, which would indicate that intense running and opiate abuse have a similar biochemical effect.

Running rodents
The team divided 44 male rats and 40 female rats into four groups. One group was housed inside an exercise wheel, and another group had none. Each group was divided again, either allowing access to food for only one hour per day or for 24 hours per day. Though tests on humans would be needed to confirm this research, rodents are typically good analogues to illuminate how the human body works.
The rodents existed in these environments for several weeks. Finally, all groups were given Naloxone, a drug used to counteract an opiate overdose and produce immediate withdrawal symptoms.

The active rats displayed a significantly higher level of withdrawal symptoms than the inactive rats. Also, the active rats that were only allowed food for one hour per day exercised the most and showed the most intense reaction to Naloxone. This scenario mimics the actions of humans suffering from anorexia athletica, also known as hypergymnasia, that causes an obsession not only with weight but also with continuous exercise to lose weight.

"Exercise, like drugs of abuse, leads to the release of neurotransmitters such as endorphins and dopamine, which are involved with a sense of reward," Kanarek said. "As with food intake and other parts of life, moderation seems to be the key. Exercise, as long as it doesn't interfere with other aspects of one's life, is a good thing with respect to both physical and mental health."

The study appears in the August issue of Behavioral Neuroscience, published by the American Psychological Association.

Treatment ideas
Kanarek hopes to use these results to design treatment programs for heroin and morphine addicts that substitute the all-natural high of exercise in place of the drugs.  "These findings, in conjunction with results of studies demonstrating that intake of drugs of abuse and running activates the endogenous opioid and dopamine reward systems, suggest that it might be possible to substitute drug-taking behavior with naturally rewarding behavior," she writes.

She also wants to do further research on understanding the neurophysiology of extreme eating and exercise disorders. "The high comorbidity of drug abuse and eating disorders provides further evidence of a common neurobiological basis for these disorders," Kanarek concludes.

Take Your Brain To The Gym

The moment of truth has arrived, again. The holidays have passed, the bowl games are over and you have renewed your annual New Year's resolution to get back into shape... for real. Don't worry, you are not alone. According to the Centers for Disease Control (CDC), 63 percent of Americans have a Body Mass Index (BMI) in excess of 25 (defined as overweight), while a quarter are greater than 30 (obese).

Its not just kids that benefit from exercise. As we get older, those extra pounds start to affect other areas of our health, contributing to the onset of diabetes, hypertension and high cholesterol.

Several new studies in the last month have now built stronger links between our levels of physical activity and the health of our most important body part, the brain. Conditions such as dementia, Parkinson's, Alzheimer's and even mild age-related memory loss can be delayed by regular physical activity.

Shrinking brain

According to John Ratey, clinical associate professor of psychiatry at Harvard Medical School and author of "Spark: the revolutionary new science of exercise and the brain" (2008, Little, Brown), "Age happens. Getting older is unavoidable, but falling apart is not."

Starting at age 40, we lose about 5 percent of our brain volume per decade, but then at age 70 other conditions may start to accelerate the deterioration. As we age, our cells are less able to cope with stress from waste products such as free radicals.

In the brain, as this stress claims more neuron cells, the web of interconnections between neurons weakens. As we each have more than one hundred billion neurons with each having oodles of connections to other neurons, this gradual net loss is not as dramatic, at first. However, as we age, if this neurodegenerative process accelerates, then our general focus and memory loss as well as more serious conditions like Alzheimer's may appear.

What the aging brain needs is a pumped-up blood flow. Exercise-induced neurotrophins such as brain-derived neurotropic factor (BDNF), vascular endothelial growth factor (VEGF), as well as the neurotransmitter dopamine are needed to grow and fertilize new and existing neurons and their synapse connections. Ratay calls BDNF "Miracle-Gro for the brain."

Make new brain cells

Researchers at the National Cheng Kung University Medical College in Taiwan recently tested the effects of BDNF in the brains of mice of different ages. Half were trained to run a maze for 1 hour a day for exercise, while the control group did not exercise.

As expected, the researchers first found that neurogenesis, the creation of new neuron cells in the brain, dropped of dramatically in the middle-aged mice compared with younger mice. They also were able to conclude that exercise significantly slows down the loss of new nerve cells in the middle-aged mice.

Production of neural stem cells improved by approximately 200 percent compared to the middle-aged mice that did not exercise.

Increase blood flow

OK, that was mice. What about humans?  University of North Carolina brain researchers recently found that older adult humans who regularly exercised had increased blood flow in their brains. They compared long-time exercisers with sedentary adults using 3D MRI brain-scanning techniques.

"The active adults had more small blood vessels and improved cerebral blood flow," said the study's senior author, J. Keith Smith, associate professor of radiology at UNC School of Medicine. "These findings further point out the importance of regular exercise to healthy aging."

The research builds on a host of other studies, summarized in an August review, that show a balanced diet and regular exercise can protect the brain and ward off mental disorders.

Helps manage glucose

Finally, in a report released last month, Scott A. Small, associate professor of neurology at Columbia University Medical Center, found that levels of blood sugar (glucose) have a direct effect on blood flow in the brain.

By testing 240 elderly volunteers, and using functional magnetic resonance imaging (fMRI), Small and his colleagues found a correlation between elevated blood glucose levels and decreased cerebral blood flow, in the dentate gyrus, an area in the brain's hippocampus that has a direct effect on our memories. This corresponds with Smith's findings by showing that exercise may help manage glucose levels, which will improve blood flow to the brain.

Small's previous imaging studies have shown that physical exercise causes an improvement in dentate gyrus function.

"By improving glucose metabolism, physical exercise also reduces blood glucose" Small said. "We have a behavioral recommendation — physical exercise."

Please visit my other articles on Livescience.com