Pavlov’s Rats? Rodents Trained to Link Rewards to Visual Cues

Jan. 23, 2013 — In experiments on rats outfitted with tiny goggles, scientists say they have learned that the brain’s initial vision processing center not only relays visual stimuli, but also can “learn” time intervals and create specifically timed expectations of future rewards. The research, by a team at the Johns Hopkins University School of Medicine and the Massachusetts Institute of Technology, sheds new light on learning and memory-making, the investigators say, and could help explain why people with Alzheimer’s disease have trouble remembering recent events.


 

Results of the study, in the journalNeuron, suggest that connections within nerve cell networks in the vision-processing center can be strengthened by the neurochemical acetylcholine (ACh), which the brain is thought to secrete after a reward is received. Only nerve cell networks recently stimulated by a flash of light delivered through the goggles are affected by ACh, which in turn allows those nerve networks to associate the visual cue with the reward. Because brain structures are highly conserved in mammals, the findings likely have parallels in humans, they say.

“We’ve discovered that nerve cells in this part of the brain, the primary visual cortex, seem to be able to develop molecular memories, helping us understand how animals learn to predict rewarding outcomes,” says Marshall Hussain Shuler, Ph.D., assistant professor of neuroscience at the Institute for Basic Biomedical Sciences at the Johns Hopkins University School of Medicine.

To maximize survival, an animal’s brain has to remember what cues precede a positive or negative event, allowing the animal to alter its behavior to increase rewards and decrease mishaps. In the Hopkins-MIT study, the researchers sought clarity about how the brain links visual information to more complex information about time and reward.

The presiding theory, Hussain Shuler says, assumed that this connection was made in areas devoted to “high-level” processing, like the frontal cortex, which is known to be important for learning and memory. The primary visual cortex seemed to simply receive information from the eyes and “re-piece” the visual world together before presenting it to decision-making parts of the brain.

To monitor the vision-reward connection process, the team fitted rats with special goggles that let researchers flash a light before either their left or right eye. Thirsty rats with goggles were given access to a water spout inside a testing chamber. When they approached the water spout, a brief visual cue was presented to one eye.

If light was sent to the left eye, the water spout would have to be licked a few times before water came to the rat; if light was sent to the right eye, the rat would have to lick many more times before water came. After a few daily sessions of such “conditioning” (not unlike Pavlov’s famous dog-bell-reward experiments), the rats learned how long they would have to lick before getting a water reward. If they didn’t get the reward in the expected amount of time, they would give up and leave the spout.

Monitoring the pattern of electrical signals given off by individual nerve cells in the rat brains, the researchers found that the signals’ “spikes” weren’t just reflecting the visual cue alone. Rather, the signals seemed to relay the time of expected reward delivery through altered spiking patterns. They also saw that many nerve cells seemed to report one or the other visual cue-reward interval, but not both. In cells stimulated by a flash to the left eye, the electrical signal returned to its baseline after a short delay, in sync with the timing of the water reward; a cue to the right eye correlated with a longer delay, also in sync with the reward. According to the researchers, the amount of time that passed before nerve cells returned to their resting state was the brain’s way of setting up a “timed expectation.”

Knowing that the basal forebrain is implicated in learning, the researchers wanted to know if their observations could be explained by nerves from the basal forebrain delivering ACh to the vision-processing center. To remove those nerve cells from the equation, they paired a neurotoxin with a “homing device” that targets only ACh-releasing neurons coming from the basal forebrain. They then repeated their experiments in trained rats that received the neurotoxin and in those that didn’t, and found that the nerve cell signals continued to relay the old time intervals, suggesting that ACh and the basal forebrain weren’t needed to express previously learned time information.

The researchers next used those same rats to ask if ACh is necessary for nerve cells to learn new time delays. To do that, they switched the visual cues so that a flash in the left eye meant a long delay and one in the right eye meant a short one. Vision-processing nerve cells in the rats in which ACh delivery was left intact adapted their signals to the new associations; but those in the rats that no longer received ACh continued to relay the old associations, suggesting that ACh is necessary to make new associations but not to express old ones.

Hussain Shuler explains, “When a reward is received, ACh is sent throughout the brain and reinforces only those nerve cell connections that were recently active. The process of conditioning continues to strengthen these nerve connections, giving rise to a timed expectation of reward in the brain.”

According to Hussain Shuler, studies have shown that Alzheimer’s patients have low levels of ACh and have trouble forming new memories. Though medication may elevate ACh, alleviation of symptoms is limited. “Our research explains that limitation,” he says. “Therapeutically, we predict that the problem isn’t just low levels of ACh — the timing of ACh delivery is key.”

Other authors of the report include Emma Roach of the Johns Hopkins University School of Medicine and Alexander Chubykin and Mark Bear of the Massachusetts Institute of Technology.

This work was supported by grants from the National Institute of Mental Health (R01MH084911), the National Institute on Drug Abuse (F31DA026687), the National Eye Institute (R01EYO12309), the National Institute of Child Health and Human Development (R01HD046943) and The Johns Hopkins University.

 

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Johns Hopkins Medicine (2013, January 23). Pavlov’s rats? Rodents trained to link rewards to visual cues. ScienceDaily. Retrieved January 28, 2013, from http://www.sciencedaily.com/releases/2013/01/130123195834.htm
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Many Apples a Day Keep the Blues at Bay

Jan. 23, 2013 — Eating more fruit and vegetables may make young people calmer, happier and more energetic in their daily life, new research from the University of Otago suggests.


 

Department of Psychology researcher Dr Tamlin Conner, and Dr Caroline Horwath and Bonnie White from Otago’s Department of Human Nutrition, investigated the relationship between day-to-day emotions and food consumption.

The study is published in the British Journal of Health Psychology on January 24.

A total of 281 young adults (with a mean age of 20 years) completed an internet-based daily food diary for 21 consecutive days. Prior to this, participants completed a questionnaire giving details of their age, gender, ethnicity, weight and height. Those with a history of an eating disorder were excluded.

On each of the 21 days participants logged into their diary each evening and rated how they felt using nine positive and nine negative adjectives. They were also asked five questions about what they had eaten that day. Specifically, participants were asked to report the number of servings eaten of fruit (excluding fruit juice and dried fruit), vegetables (excluding juices), and several categories of unhealthy foods like biscuits/cookies, potato crisps, and cakes/muffins.

The results showed a strong day-to-day relationship between more positive mood and higher fruit and vegetable consumption, but not other foods.

“On days when people ate more fruits and vegetables, they reported feeling calmer, happier and more energetic than they normally did,” says Dr Conner.

To understand which comes first — feeling positive or eating healthier foods — Dr Conner and her team ran additional analyses and found that eating fruits and vegetables predicted improvements in positive mood the next day, suggesting that healthy foods may improve mood. These findings held regardless of the BMI of individuals.

“After further analysis we demonstrated that young people would need to consume approximately seven to eight total servings of fruits and vegetables per day to notice a meaningful positive change. One serving of fruit or vegetables is approximately the size that could fit in your palm, or half a cup. My co-author Bonnie White suggests that this can be done by making half your plate at each meal vegetables and snacking on whole fruit like apples,” says Dr Conner.

She adds that while this research shows a promising connection between healthy foods and healthy moods, further research is necessary and the authors recommend the development of randomised control trials evaluating the influence of high fruit and vegetable intake on mood and wellbeing.

 

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University of Otago (2013, January 23). Many apples a day keep the blues at bay.ScienceDaily. Retrieved January 28, 2013, from http://www.sciencedaily.com/releases/2013/01/130123195351.htm

Frequent Multitaskers Are Bad at It: Can’t Talk and Drive Well

Jan. 23, 2013 — Most people believe they can multitask effectively, but a University of Utah study indicates that people who multitask the most — including talking on a cell phone while driving — are least capable of doing so.


“What is alarming is that people who talk on cells phones while driving tend to be the people least able to multitask well,” says psychology Professor David Sanbonmatsu, a senior author of the study. “Our data suggest the people talking on cell phones while driving are people who probably shouldn’t. We showed that people who multitask the most are those who appear to be the least capable of multitasking effectively.”

The new study was scheduled for publication Jan. 23 in PLOS ONE, an online journal of the Public Library of Science.

The other senior author, University of Utah psychology Professor David Strayer, adds, “The people who are most likely to multitask harbor the illusion they are better than average at it, when in fact they are no better than average and often worse.”

Citing humorist Garrison Keillor’s catchphrase about kids in Keillor’s fictitious hometown, Strayer says people who use cell phones while driving “all think they live in Lake Wobegon, where everybody is above average. But it’s a statistical impossibility.”

The study ran 310 undergraduate psychology students through a battery of tests and questionnaires to measure actual multitasking ability, perceived multitasking ability, cell phone use while driving, use of a wide array of electronic media, and personality traits such as impulsivity and sensation-seeking.

The key findings:

  • “The persons who are most capable of multitasking effectively are not the persons who are most likely to engage in multiple tasks simultaneously.” Instead, people who score high on a test of actual multitasking ability tend not to multitask because they are better able to focus attention on the task at hand.
  • The more people multitask by talking on cell phones while driving or by using multiple media at once, the more they lack the actual ability to multitask, and their perceived multitasking ability “was found to be significantly inflated.” In fact, 70 percent of participants thought they were above average at multitasking, which is statistically impossible.
  • People with high levels of impulsivity and sensation-seeking reported more multitasking. However, there was an exception: People who talk on cell phones while driving tend not to be impulsive, indicating that cell phone use is a deliberate choice.
  • The research suggests that people who engage in multitasking often do so not because they have the ability, but “because they are less able to block out distractions and focus on a singular task.”

The researchers conclude, “The negative relation between cellular communication while driving and multitasking ability appears to further bolster arguments for legislation limiting the use of cell phones while operating a motor vehicle.”

Sanbonmatsu and Strayer conducted the study with University of Utah co-authors Jason Watson, an associate professor of psychology, and Nathan Medeiros-Ward, a doctoral student in psychology. The study was funded by the American Automobile Association Foundation for Traffic Safety.

How the Study Was Performed

The researchers say that while people frequently multitask to try to achieve several goals at once, “relatively little is known about when and why people perform more than one attention-demanding task at a time. Related to this, little is known about who is most likely to multitask.”

The study participants were 310 University of Utah psychology undergraduates — 176 female and 134 male with a median age of 21 — who volunteered for their department’s subject pool in exchange for extra course credit.

To measure actual multitasking ability, participants performed a test named Operation Span, or OSPAN. The test involves two tasks: memorization and math computation. Participants must remember two to seven letters, each separated by a math equation that they must identify as true or false. A simple example of a question: “is 2+4=6?, g, is 3-2=2?, a, is 4×3=12.” Answer: true, g, false, a, true.

Participants also ranked their perceptions of their own multitasking ability by giving themselves a score ranging from zero to 100, with 50 percent meaning average.

Study subjects reported how often they used a cell phone while driving, and what percentage of the time they are on the phone while driving. They also completed a survey of how often and for how many hours they use which media, including printed material, television and video, computer video, music, nonmusic audio, video games, phone, instant and text messaging, e-mail, the Web and other computer software such as word processing. The results were used to compute an index of media multitasking.

They also completed well-established questionnaires that measure impulsivity and sensation-seeking.

Who Multitasks and Why?

The researchers looked for significant correlations among results of the various tests and questionnaires.

“The people who multitask the most tend to be impulsive, sensation-seeking, overconfident of their multitasking abilities, and they tend to be less capable of multitasking,” says Strayer, summarizing the findings.

The 25 percent of the people who performed best on the OSPAN test of multitasking ability “are the people who are least likely to multitask and are most likely to do one thing at a time,” Sanbonmatsu says.

In contrast, 70 percent of participants said they were above-average at multitasking, and they were more likely to multitask.

“One of the main reasons people multitask is because they think they are good at it,” Sanbonmatsu says. “But our study suggests people rarely are as good at multitasking as they think they are.”

Multitasking ability on the OSPAN was significantly and negatively correlated with actual media multitasking and cell phone use while driving, meaning the people who multitask the most have the least ability to do so.

“If you have people who are multitasking a lot, you might come to the conclusion they are good at multitasking,” Strayer says. “In fact, the more likely they are to do it, the more likely they are to be bad at it.”

Sanbonmatsu adds: “Our data show people multitask because they have difficulty focusing on one task at a time. They get drawn into secondary tasks. … They get bored and want that stimulation of talking while they are driving.”

Study participants reported spending 13 percent of their driving time talking on a cell phone, which Strayer says roughly squares with federal estimates that one in 10 drivers are on the phone at any given time.

Media multitasking — except cell phone use while driving — correlated significantly with impulsivity, particularly the inability to concentrate and acting without thinking. Impulsive people tend to be more reward-oriented and more apt to take risks, so they may be less sensitive to the costs of multitasking, the researchers say.

Multitasking, including cell phone use while driving, correlated significantly with sensation-seeking, indicating some people multitask because it is more stimulating, interesting and challenging, and less boring — even if it may hurt their overall performance.

 

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The above story is reprinted from materials provided byUniversity of Utah.

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Journal Reference:

  1. David M. Sanbonmatsu, David L. Strayer, Nathan Medeiros-Ward, Jason M. Watson. Who Multi-Tasks and Why? Multi-Tasking Ability, Perceived Multi-Tasking Ability, Impulsivity, and Sensation SeekingPLoS ONE, 2013; 8 (1): e54402 DOI: 10.1371/journal.pone.0054402
University of Utah (2013, January 23). Frequent multitaskers are bad at it: Can’t talk and drive well. ScienceDaily. Retrieved January 28, 2013, from http://www.sciencedaily.com/releases/2013/01/130123195101.htm

Children’s Complex Thinking Skills Begin Before Going to School

Jan. 23, 2013 — New research at the University of Chicago and the University of North Carolina at Chapel Hill shows that children begin to show signs of higher-level thinking skills as young as age 4 ½. Researchers have previously attributed higher-order thinking development to knowledge acquisition and better schooling, but the new longitudinal study shows that other skills, not always connected with knowledge, play a role in the ability of children to reason analytically.


The findings, reported in January in the journal Psychological Science, show for the first time that children’s executive function has a role in the development of complicated analytical thinking. Executive function includes such complex skills as planning, monitoring, task switching, and controlling attention. High, early executive function skills at school entry are related to higher than average reasoning skills in adolescence.

Growing research suggests that executive function may be trainable through pathways, including preschool curriculum, exercise and impulse control training. Parents and teachers may be able to help encourage development of executive function by having youngsters help plan activities, learn to stop, think, and then take action, or engage in pretend play, said lead author of the study, Lindsey Richland, assistant professor in comparative human development at the University of Chicago.

Although important to a child’s education, “little is known about the cognitive mechanisms underlying children’s development of the capacity to engage in complex forms of reasoning,” Richland said.

The new research is reported in the paper “Early Executive Function Predicts Reasoning Development” and follows the development of complex reasoning in children from before the time they go to school until they are 15. Richland’s co-author is Margaret Burchinal, senior scientist at the Frank Porter Graham Child Development Institute at the University of North Carolina at Chapel Hill.

The two studied the acquisition of analogical thinking, one form of complex reasoning. “The ability to see relationships and similarities between disparate phenomena is fundamental to analytical and inductive reasoning, and is closely related to measurements of general fluid intelligence,” said Richland. Developing complex reasoning ability is particularly fundamental to the innovation and adaptive thinking skills necessary for a modern workforce, she pointed out.

Richland and Burchinal studied a database of 1,364 children who were part of the Early Child Care and Youth Development study from birth through age 15. The group was fairly evenly divided between boys and girls and included families from a diverse cross-section of ethnic and income backgrounds.

The current study examined tests children took when they were 4 ½, when they were in first grade, third grade, and when they were 15. Because the study was longitudinal, the same children were tested at each interval. Among the tests they took were ones to measure analytical reasoning, executive function, vocabulary knowledge, short-term memory and sustained attention.

Children were tested at 4 ½ on their ability to monitor and control their automatic responses to stimuli. In first grade they worked on a test that judged their ability to move objects in a “Tower of Hanoi” game, in which they had to move disks between pegs in a specific order.

In third grade and at 15 year olds, they were tested on their ability to understand analogies, asked in third grade for instance to complete the question “dog is to puppy as cat is to__?” At 15 year olds, they were asked to complete written tests of analogies.

The study found a strong relationship between high scores among children who, as preschoolers, had strong vocabularies and were good at monitoring and controlling their responses to later ability on tests of understanding analogies.

“Overall, these results show that knowledge is necessary for using thinking skills, as shown by the importance of early vocabulary, but also inhibitory control and executive function skills are important contributors to children’s analytical reasoning development,” Richland said.

The National Academy of Education/Spencer Foundation, the Office of Naval Research and the National Science Foundation supported the research.

 

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The above story is reprinted from materials provided byUniversity of Chicago.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Journal Reference:

  1. L. E. Richland, M. R. Burchinal. Early Executive Function Predicts Reasoning DevelopmentPsychological Science, 2012; 24 (1): 87 DOI:10.1177/0956797612450883
University of Chicago (2013, January 23). Children’s complex thinking skills begin before going to school. ScienceDaily. Retrieved January 28, 2013, from http://www.sciencedaily.com/releases/2013/01/130123164858.htm

Learning and Memory May Play a Central Role in Synesthesia: Link to Childhood Toys Containing Magnetic Colored Letters

Jan. 23, 2013 — People with color-grapheme synesthesia experience color when viewing written letters or numerals, usually with a particular color evoked by each grapheme (i.e., the letter ‘A’ evokes the color red). In a new study, researchers Nathan Witthoft and Jonathan Winawer of Stanford University present data from 11 color grapheme synesthetes who had startlingly similar color-letter pairings that were traceable to childhood toys containing magnetic colored letters.

 (Credit: © teressa / Fotolia)

 

Their findings are published inPsychological Science, a journal of the Association for Psychological Science.

Matching data from the 11 participants showed reliably consistent letter-color matches, both within and between testing sessions (data collected online athttp://www.synesthete.org/). Participants’ matches were consistent even after a delay of up to seven years since their first session.

Participants also performed a timed task, in which they were presented with colored letters for 1 second each and required to indicate whether the color was consistent with their synesthetic association. Their data show that they were able to perform the task rapidly and accurately.

Together, these data suggest that the participants’ color-letter associations are specific, automatic, and relatively constant over time, thereby meeting the criteria for true synesthesia.

The degree of similarity in the letter-color pairings across participants, along with the regular repeating pattern in the colors found in each individual’s letter-color pairings, indicates that the pairings were learned from the magnetic colored letters that the participants had been exposed to in childhood.

According to the researchers, these are the first and only data to show learned synesthesia of this kind in more than a single individual.

They point out that this does not mean that exposure to the colored letter magnets was sufficient to induce synesthesia in the participants, though it may have increased the chances. After all, many people who do not have synesthesia played with the same colored letter magnets as kids.

Based on their findings, Witthoft and Winawer conclude that a complete explanation of synesthesia must incorporate a central role for learning and memory.

 

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The above story is reprinted from materials provided byAssociation for Psychological Science.

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Journal Reference:

  1. N. Witthoft, J. Winawer. Learning, Memory, and SynesthesiaPsychological Science, 2013; DOI:10.1177/0956797612452573
Association for Psychological Science (2013, January 23). Learning and memory may play a central role in synesthesia: Link to childhood toys containing magnetic colored letters.ScienceDaily. Retrieved January 28, 2013, from http://www.sciencedaily.com/releases/2013/01/130123144220.htm

New Brain Circuit Sheds Light On Development of Voluntary Movements

Jan. 23, 2013 — All parents know the infant milestones: turning over, learning to crawl, standing, and taking that first unassisted step. Achieving each accomplishment presumably requires the formation of new connections among subsets of the billions of nerve cells in the infant’s brain. But how, when and where those connections form has been a mystery.

A mouse pup learns to use its whiskers to sense objects at about the second week of life. The nerve connections that enable this activity are helping researchers at Duke Medicine learn how human brains develop and function. (Credit: Image courtesy of Duke University Medical Center)

Now researchers at Duke Medicine have begun to find answers. In a study reported Jan. 23, 2013, in the scientific journal Neuron, the research team describes the entire network of brain cells that are connected to specific motor neurons controlling whisker muscles in newborn mice.

A better understanding of such motor control circuits could help inform how human brains develop, potentially leading to new ways of restoring movement in people who suffer paralysis from brain injuries, or to the development of better prosthetics for limb replacement.

“Whiskers to mice are like fingers to humans, in that both are moving touch sensors,” said lead investigator Fan Wang, PhD, associate professor of cell biology and member of the Duke Institute for Brain Sciences. “Understanding how the mouse’s brain controls whisker movements may tell us about neural control of finger movements in people.”

Mice are active at night, so they rely heavily on whiskers to detect and discriminate objects in the dark, brushing their whiskers against objects in a rhythmic back-and-forth sweeping pattern referred to as “whisking.” But this whisking behavior does not appear until about two weeks after birth, when young mice start to explore the world outside their nest.

To learn how motor control of whiskers takes place, Wang and postdoctoral fellow Jun Takatoh used a new technique that takes advantage of the rabies virus’ ability to spread through connected nerve cells. A disabled form of the virus used to vaccinate pets was created with the ability to express a fluorescent protein. The researchers were able to trace its path through a network of brain cells directly connected to the motor neurons controlling whisker movement.

“The precision of this mapping method allowed us to ask a key question, namely are parts of the whisker motor control circuitry not yet connected in newborn mice, and are such missing links added later to enable whisking?” Wang said.

By taking a series of pictures in the fluorescently labeled brains during the first two weeks after birth, the research team chronicled the developing circuits before and after mice start whisking.

“When we traced the circuit it was stunning in the sense that we didn’t realize there are so many pools of neurons located throughout the brainstem that are connected to whisker motor neurons,” said Wang. “It’s remarkable that a single motor neuron receives so many inputs, and somehow is able to integrate them.”

At the same time whisking movements emerge, motor neurons receive a new set of inputs from a region of the brainstem called the LPGi. A single LPGi neuron is connected to motor neurons on both sides of the face, putting them in perfect position to synchronize the movements of left and right whiskers.

To learn more about the new circuit formed between LPGi and motor neurons, Wang and Takatoh drew on the expertise of Duke colleague Richard Mooney, PhD, professor of neurobiology, and his student Anders Nelson. Together, the researchers were able to record the labeled neurons and found the LPGi neurons communicate with motor neurons using glutamate, the main neurotransmitter that stimulates the brain. They further discovered that LPGi neurons receive direct inputs from the motor cortex.

“This makes sense because exploratory whisking is a voluntary movement under control of the motor cortex,” Wang said. “Excitatory input is needed for initiating such movements, and LPGi may be critical for relaying signals from the motor cortex to whisker motor neurons.”

The researchers will next explore the connectivity by using genetic, viral and optical tools to see what happens when certain components of the circuits are activated or silenced during various motor tasks.

In addition to Wang, Takatoh, Mooney and Nelson at Duke, study authors include Xiang Zhou of the University of Chicago; Michael D. Ehlers of Pfizer Inc. R&D; M. McLean Bolton of the Max Planck Institute; and Benjamin R. Arenkiel of Baylor College of Medicine.

The research was supported by grants from the National Institutes of Health (DA028302, DE19440, NS079929) and by the Duke Institute for Brain Sciences.

 

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The above story is reprinted from materials provided byDuke University Medical Center.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Journal Reference:

  1. Jun Takatoh, Anders Nelson, Xiang Zhou, M. McLean Bolton, Michael D. Ehlers, Benjamin R. Arenkiel, Richard Mooney, Fan Wang. New Modules Are Added to Vibrissal Premotor Circuitry with the Emergence of Exploratory WhiskingNeuron, 2013; 77 (2): 346 DOI:10.1016/j.neuron.2012.11.010
Duke University Medical Center (2013, January 23). New brain circuit sheds light on development of voluntary movements.ScienceDaily. Retrieved January 28, 2013, from http://www.sciencedaily.com/releases/2013/01/130123133610.htm

Exercise: Women Must Do More to Reap Same Positive Health Outcomes as Men

Jan. 23, 2013 — More than one-third of Americans are obese, and these individuals often experience accompanying health issues, such as Type 2 diabetes and cardiovascular problems. In response to the so-called “obesity epidemic,” many medical professionals have suggested ways to improve the health outcomes of obese individuals through diet and exercise. Now, research conducted at the University of Missouri suggests certain exercises that benefit obese men may not have the same positive results for obese women. These findings could help health providers and researchers develop targeted exercise interventions for obese women.


“Our results indicate gender may contribute to differences in cardiovascular function of obese individuals with Type 2 diabetes,” said Jill Kanaley, a professor in the Department of Nutrition and Exercise Physiology at MU. “Men saw improvement after aerobic exercise training, but the women did not experience the same benefits.”

Kanaley and her colleagues monitored cardiovascular responses, such as heart rate and blood pressure, of nearly 75 obese men and women with Type 2 diabetes. To monitor cardiovascular responses, the individuals completed an isometric handgrip test, which involves continually and forcefully squeezing an object for a few minutes, at the beginning and end of a structured, 16-week walking program.

“What this research highlights, at least using the handgrip test, is that the advantages we think exercise is going to give individuals may not be the same across genders, particularly for those who have Type 2 diabetes,” Kanaley said. “This is a concern because there are high mortality rates with Type 2 diabetes, especially for women. We’re trying to find successful interventions to help these individuals, and we keep assuming that exercise will do the trick — we think when we tell people to “go train,” regardless of gender, everyone will get the same results. Our research indicates certain exercises may not be enough for women, as our walking program did not show positive improvements for them.”

Obese women with Type 2 diabetes might benefit from longer durations or higher intensities of exercise, Kanaley said. In addition, Kanaley said more concern should be placed on how long it takes cardiovascular function to return to normal after exercise as well as how fast the heart beats during physical exertion.

“A lot of people focus on how high individuals’ heart rates get during exercise, but their recovery rates also should be monitored,” Kanaley said. “When you exercise, you want your blood pressure to rise, but you don’t want it to get too high. Your blood pressure should return to normal relatively quickly after you stop exercise. In our study, the recovery rate for women was not as rapid as for men. After the men trained, they got an even better recovery time, whereas women’s time stayed about the same.”

The study, “Exercise training improves hemodynamic recovery to isometric exercise in obese men with Type 2 diabetes but not in obese women,” was published in the December issue of Metabolism.

 

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The above story is reprinted from materials provided byUniversity of Missouri-Columbia.

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Journal Reference:

  1. Jill A. Kanaley, Styliani Goulopoulou, Ruth Franklin, Tracy Baynard, Robert L. Carhart, Ruth S. Weinstock, Bo Fernhall. Exercise training improves hemodynamic recovery to isometric exercise in obese men with type 2 diabetes but not in obese womenMetabolism, 2012; 61 (12): 1739 DOI: 10.1016/j.metabol.2012.07.014
University of Missouri-Columbia (2013, January 23). Exercise: Women must do more to reap same positive health outcomes as men.ScienceDaily. Retrieved January 28, 2013, from http://www.sciencedaily.com/releases/2013/01/130123115411.htm

Benefits of Social Grooming in Wild Chimpanzees: Hormone Oxytocin Facilitates Cooperation

Jan. 23, 2013 — Animals which maintain cooperative relationships show gains in longevity and offspring survival. However, little is known about the cognitive or hormonal mechanisms involved in cooperation. Researchers of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, have now found that cooperative relationships are facilitated by an endocrinological mechanism involving the hormone oxytocin, even when these are between non-kin.


They collected urine samples of 33 chimpanzees from Budongo Forest, Uganda, and measured their urinary oxytocin levels after single episodes of a specific cooperative behavior, mutual grooming. The result: Oxytocin levels were higher after grooming with cooperation partners compared with non-cooperation partners or after no grooming, regardless of genetic relatedness or sexual interest. This suggests that in chimpanzees oxytocin, which acts directly on neural reward and social memory systems, plays a key role maintaining social relations beyond genetic ties and in keeping track of social interactions with multiple individuals over time.

In non-human primates and other social animals strong and enduring social bonds are typically seen between genetically related individuals but also, occasionally, between non-kin, same-sex individuals. Although such relationships are typically defined by high rates of cooperative behaviors, how they are maintained over time is still unclear. In humans and other social mammals the neuropeptide hormone oxytocin plays a central role in facilitating bonding between kin and mating partners. Catherine Crockford, Roman Wittig and colleagues of the Max Planck Institute for Evolutionary Anthropology have now analyzed the role of this hormone in the social relationships between wild chimpanzees.

To this end the researchers observed social interactions – like mutual grooming – in a group of wild chimpanzees from Budongo Forest in Uganda and non-invasively collected urine samples of the 33 female and male adult group members on plastic bags or leaves. They determined the level of the hormone oxytocin before and shortly after the animals had been grooming with each other and found that oxytocin levels were especially high in chimpanzees who had been grooming with a “bond partner”,  a cooperation partner, irrespective of whether this bond partner happened to be their kin or not. On the other hand, the level of urinary oxytocin was much lower in chimpanzees who had been grooming with a “non-bond partner”, with whom they did not share a cooperative relationship, or in animals who had not been grooming at all. Furthermore, the researchers found that the animal’s sex or age, grooming duration and other factors did not have a significant influence on urinary oxytocin levels.

“Our results demonstrate that a rise in oxytocin was dependent upon the combined effects of social grooming with a bond partner”, says Catherine Crockford of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. “Crucially, oxytocin levels were similarly high after grooming with non-kin and kin bond partners. This suggests that, in chimpanzees, oxytocin plays a key role in maintaining social relations beyond immediate genetic ties”.

“This is the first study that measures the levels of the hormone oxytocin on wild animals in a non-invasive way”, says Roman Wittig of the Max Planck Institute for Evolutionary Anthropology. “We have developed a tool with which cross-species comparisons that link underlying physiology and behavior can eventually be made of social mammals in their natural environment”. In future field research this tool will be used to compare single behaviors – like other cooperative  or aggressive behaviors–by measuring how they differ from each other hormonally.

 

Story Source:

The above story is reprinted from materials provided byMax-Planck-Gesellschaft.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Journal Reference:

  1. C. Crockford, R. M. Wittig, K. Langergraber, T. E. Ziegler, K. Zuberbuhler, T. Deschner. Urinary oxytocin and social bonding in related and unrelated wild chimpanzees.Proceedings of the Royal Society B: Biological Sciences, 2013; 280 (1755): 20122765 DOI: 10.1098/rspb.2012.2765
Max-Planck-Gesellschaft (2013, January 23). Benefits of social grooming in wild chimpanzees: Hormone oxytocin facilitates cooperation. ScienceDaily. Retrieved January 28, 2013, from http://www.sciencedaily.com/releases/2013/01/130123094251.htm

How the Purple and Pink Sunscreens of Reef Corals Work

Jan. 23, 2013 — New research by the University of Southampton has found a mechanism as to how corals use their pink and purple hues as sunscreen to protect them against harmful sunlight.

Pocillopora damicornis coral from the Red Sea expressing a pink photoprotective chromoprotein. (Credit: Image courtesy of University of Southampton)
 

Many reef corals need light to survive, as they benefit from sugars and lipids that are produced by their light-dependent symbiotic algae. However, in the shallow water of coral reefs, light levels are often higher than required by the corals, so paradoxically, the vital sunlight can become harmful for the algae and their hosts.

Apart from temperature, light stress is a major driver of coral bleaching — the loss of the symbiotic algae that represents a threat to coral reef survival.

Working in the Great Barrier Reef and under tightly controlled conditions in the Coral Reef Laboratory of the University of Southampton, the team of researchers produced experimental evidence that the pink and purple chromoproteins can act as sunscreens for the symbiotic algae by removing parts of the light that might become otherwise harmful.

Dr Jörg Wiedenmann, Senior Lecturer of Biological Oceanography and Head of the University’s Coral Reef Laboratory, who led the study says: “The beautiful pink and purple hues that are produced by the coral host are often evoked by chromoproteins; pigments that are biochemically related to the green fluorescent protein (GFP) of the jellyfish Aequorea victoria. In contrast to their green glowing counterpart, the chromoproteins take up substantial amounts of light, but they don’t re-emit light.

“GFP-like proteins were suggested to contribute to the protection of corals and their symbionts from excess sunlight. This hypothesis has been controversially discussed as the mechanism as to how these pigments function remained unclear. At least for the chromoproteins we know now that they have indeed the capacity to fulfill this function.” The researchers also proposed an explanation for the mysterious phenomenon that some corals accumulate exceptionally high amounts of chromoproteins in growing areas, such as branch tips or in the region of healing wounds.

Dr Wiedenmann, who is based at the National Oceanography Centre, Southampton, explains: “These growing areas contain essentially no symbiotic algae, so much of the light is reflected by the white coral skeleton instead of being used by the algae. The resulting increased light intensities in the new parts of the coral represent a potential danger for the algal cells that need to colonise these areas. Hence, it seems that the corals use a clever trick to help their symbionts. The higher light intensity switches on the genes that are responsible for the production of the sunscreening chromoproteins.

“Our results suggest that the screening effect of the chromoproteins could help the algae to enter the new tissue. Once the symbiont population is fully established, the light levels in the tissue decrease as the algae use most of the light for photosynthesis. As a consequence, the genes of the chromoproteins are switched off again which allows the coral to save the energy required for their production.”

The research contributes to a better understanding of the coral’s response to environmental stress. Knowledge of the stress resilience of corals is an important requirement to help predictions of the fate of coral reefs that are exposed to climate change and various forms of anthropogenic disturbance.

The paper is published in the latest edition of the journalCoral Reefs.

 

Story Source:

The above story is reprinted from materials provided byUniversity of Southampton.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Journal Reference:

  1. E. G. Smith, C. D’Angelo, A. Salih, J. Wiedenmann.Screening by coral green fluorescent protein (GFP)-like chromoproteins supports a role in photoprotection of zooxanthellaeCoral Reefs, 2013; DOI: 10.1007/s00338-012-0994-9
University of Southampton (2013, January 23). How the purple and pink sunscreens of reef corals work. ScienceDaily. Retrieved January 28, 2013, from http://www.sciencedaily.com/releases/2013/01/130123094129.htm

From Dark Hearts Comes the Kindness of Humankind

Jan. 22, 2013 — The kind­ness of humankind most likely devel oped from our more sin is ter and self-serving ten den cies, accord­ing to Prince ton Uni ver sity and Uni ver sity of Ari zona research that sug gests society’s rules against self­ish ness are rooted in the very exploita tion they condemn.


 

The report in the jour nal Evo lu tionpro poses that altru ism — society’s pro tec tion of resources and the col­lec tive good by pun ish ing “cheaters” — did not develop as a reac tion to avarice. Instead, com mu nal dis­avowal of greed orig i nated when com pet ing self ish indi vid u als sought to con trol and can cel out one another. Over time, the direct efforts of the dom i nant fat cats to con tain a few com peti tors evolved into a community-wide desire to guard its own well-being.

The study authors pro pose that a sys tem of greed dom i nat ing greed was sim ply eas ier for our human ances tors to man age. In this way, the work chal lenges dom i nant the o­ries that self ish and altru is tic social arrange ments formed inde pen dently — instead the two struc tures stand as evo lu tion ary phases of group inter­ac tion, the researchers write.

Sec ond author Andrew Gallup, a for­mer Prince ton post doc toral researcher in ecol ogy and evo lu tion­ary biol ogy now a vis it ing assis tant pro fes sor of psy chol ogy at Bard Col­lege, worked with first author Omar Eldakar, a for mer Ari zona post doc­toral fel low now a vis it ing assis tant pro fes sor of biol ogy at Ober lin Col­lege, and William Driscoll, an ecol­ogy and evo lu tion ary biol ogy doc­toral stu dent at Arizona.

To test their hypoth e sis, the researchers con structed a sim u la­tion model that gauged how a com mu nity with stands a sys tem built on altru is tic pun ish ment, or selfish-on-selfish pun ish­ment. The authors found that altru ism demands a lot of ini tial expen di ture for the group — in terms of com mu nal time, resources and risk of reprisal from the pun ished — as well as advanced lev els of cog ni tion and cooperation.

On the other hand, a con struct in which a few prof li gate play­ers keep like-minded indi vid u als in check involves only those mem bers of the com mu nity — every one else can pas sively enjoy the ben e fits of fewer peo ple tak ing more than their share. At the same time, the reign ing indi vid u als enjoy uncon­tested spoils and, in some cases, reverence.

Social orders main tained by those who bend the rules play out in nature and human his tory, the authors note: Tree wasps that police hives to make sure that no mem ber other than the queen lays eggs will often lay illicit eggs them selves. Can cer cells will pre vent other tumors from form ing. Medieval knights would pil lage the same civil ians they read ily defended from invaders, while neigh bor hoods ruled by the Ital ian Mafia tra di­tion ally had the low est lev els of crime.

What comes from these arrange ments, the researchers con­clude, is a sense of order and equal ity that the group even tu­ally takes upon itself to enforce, thus giv ing rise to altruism.

 

Story Source:

The above story is reprinted from materials provided byPrinceton University. The original article was written by Mor gan Kelly.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Journal Reference:

  1. Omar Tonsi Eldakar, Andrew C. Gallup, William Wallace Driscoll. When Hawks Give Rise To Doves: The Evo lu­tion and Tran si tion of Enforce ment Strate gies.Evolution, 2013; DOI: 10.1111/evo.12031
Princeton University (2013, January 22). From dark hearts comes the kindness of humankind.ScienceDaily. Retrieved January 27, 2013, from http://www.sciencedaily.com/releases/2013/01/130122143105.htm