Physical Activity May Strengthen Children's Ability To Pay Attention

Charles Hillman and Darla Castelli, professors of kinesiology and community health, have found that physical activity may increase students' cognitive control -- or ability to pay attention -- and also result in better performance on academic achievement tests.

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As school districts across the nation revamped curricula to meet requirements of the federal “No Child Left Behind” Act, opportunities for children to be physically active during the school day diminished significantly.

Future mandates, however, might be better served by taking into account findings from a University of Illinois study suggesting the academic benefits of physical education classes, recess periods and after-school exercise programs. The research, led by Charles Hillman, a professor of kinesiology and community health and the director of the Neurocognitive Kinesiology Laboratory at Illinois, suggests that physical activity may increase students’ cognitive control – or ability to pay attention – and also result in better performance on academic achievement tests.
“The goal of the study was to see if a single acute bout of moderate exercise – walking – was beneficial for cognitive function in a period of time afterward,” Hillman said. “This question has been asked before by our lab and others, in young adults and older adults, but it’s never been asked in children. That’s why it’s an important question.”
For each of three testing criteria, researchers noted a positive outcome linking physical activity, attention and academic achievement.
Study participants were 9-year-olds (eight girls, 12 boys) who performed a series of stimulus-discrimination tests known as flanker tasks, to assess their inhibitory control.
On one day, students were tested following a 20-minute resting period; on another day, after a 20-minute session walking on a treadmill. Students were shown congruent and incongruent stimuli on a screen and asked to push a button to respond to incongruencies. During the testing, students were outfitted with an electrode cap to measure electroencephalographic (EEG) activity.
“What we found is that following the acute bout of walking, children performed better on the flanker task,” Hillman said. “They had a higher rate of accuracy, especially when the task was more difficult. Along with that behavioral effect, we also found that there were changes in their event-related brain potentials (ERPs) – in these neuroelectric signals that are a covert measure of attentional resource allocation.”
One aspect of the neuroelectric activity of particular interest to researchers is a measure referred to as the P3 potential. Hillman said the amplitude of the potential relates to the allocation of attentional resources.
“What we found in this particular study is, following acute bouts of walking, children had a larger P3 amplitude, suggesting that they are better able to allocate attentional resources, and this effect is greater in the more difficult conditions of the flanker test, suggesting that when the environment is more noisy – visual noise in this case – kids are better able to gate out that noise and selectively attend to the correct stimulus and act upon it.”
In an effort to see how performance on such tests relates to actual classroom learning, researchers next administered an academic achievement test. The test measured performance in three areas: reading, spelling and math.
Again, the researchers noted better test results following exercise.
“And when we assessed it, the effect was largest in reading comprehension,” Hillman said. In fact, he said, “If you go by the guidelines set forth by the Wide Range Achievement Test, the increase in reading comprehension following exercise equated to approximately a full grade level.
“Thus, the exercise effect on achievement is not statistically significant, but a meaningful difference.”
Hillman said he’s not sure why the students’ performance on the spelling and math portions of the test didn’t show as much of an improvement as did reading comprehension, but suspects it may be related to design of the experiment. Students were tested on reading comprehension first, leading him to speculate that too much time may have elapsed between the physical activity and the testing period for those subjects.
“Future attempts will definitely look at the timing,” he said. Subsequent testing also will introduce other forms of physical-activity testing.
“Treadmills are great,” Hillman said. “But kids don’t walk on treadmills, so it’s not an externally valid form of exercise for most children. We currently have an ongoing project that is looking at treadmill walking at the same intensity relative to a Wii Fit game – which is a way in which kids really do exercise.”
Still, given the preliminary study’s positive outcomes on the flanker task, ERP data and academic testing, study co-author Darla Castelli believes these early findings could be used to inform useful curricular changes.
“Modifications are very easy to integrate,” Castelli said. For example, she recommends that schools make outside playground facilities accessible before and after school.
“If this is not feasible because of safety issues, then a school-wide assembly containing a brief bout of physical activity is a possible way to begin each day,” she said. “Some schools are using the Intranet or internal TV channels to broadcast physical activity sessions that can be completed in each classroom.”
Among Castelli’s other recommendations for school personnel interested in integrating physical activity into the curriculum:

• scheduling outdoor recess as a part of each school day;
• offering formal physical education 150 minutes per week at the elementary level, 225 minutes at the secondary level;
• encouraging classroom teachers to integrate physical activity into learning.

An example of how physical movement could be introduced into an actual lesson would be “when reading poetry (about nature or the change of seasons), students could act like falling leaves,” she said.
The U. of I. study appears in the current issue of the journal Neuroscience. Along with Castelli and Hillman, co-authors are U. of I. psychology professor Art Kramer and kinesiology and community health graduate student Mathew Pontifex and undergraduate Lauren Raine.
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Adapted from materials provided by University of Illinois at Urbana-Champaign.

Action Video Games Improve Vision, New Research Shows

This is a photo illustrating 58 percent better contrast perception versus "regular" contrast perception.

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Video games that involve high levels of action, such as first-person-shooter games, increase a player's real-world vision, according to research in Nature Neuroscience March 29.

The ability to discern slight differences in shades of gray has long been thought to be an attribute of the human visual system that cannot be improved. But Daphne Bavelier, professor of brain and cognitive sciences at the University of Rochester, has discovered that very practiced action gamers become 58 percent better at perceiving fine differences in contrast.
"Normally, improving contrast sensitivity means getting glasses or eye surgery—somehow changing the optics of the eye," says Bavelier. "But we've found that action video games train the brain to process the existing visual information more efficiently, and the improvements last for months after game play stopped."
The finding builds on Bavelier's past work that has shown that action video games decrease visual crowding and increases visual attention. Contrast sensitivity, she says, is the primary limiting factor in how well a person can see. Bavelier says that the findings show that action video game training may be a useful complement to eye-correction techniques, since game training may teach the visual cortex to make better use of the information it receives.
To learn whether high-action games could affect contrast sensitivity, Bavelier, in collaboration with graduate student Renjie Li and colleagues Walt Makous, professor of brain and cognitive sciences at the University of Rochester, and Uri Polat, professor at the Eye Institute at Tel Aviv University, tested the contrast sensitivity function of 22 students, then divided them into two groups: One group played the action video games "Unreal Tournament 2004" and "Call of Duty 2." The second group played "The Sims 2," which is a richly visual game, but does not include the level of visual-motor coordination of the other group's games. The volunteers played 50 hours of their assigned games over the course of 9 weeks. At the end of the training, the students who played the action games showed an average 43% improvement in their ability to discern close shades of gray—close to the difference she had previously observed between game players and non-game players—whereas the Sims players showed none.
"To the best of our knowledge, this is the first demonstration that contrast sensitivity can be improved by simple training," says Bavelier. "When people play action games, they're changing the brain's pathway responsible for visual processing. These games push the human visual system to the limits and the brain adapts to it, and we've seen the positive effect remains even two years after the training was over."
Bavelier says that the findings suggest that despite the many concerns about the effects of action video games and the time spent in front of a computer screen, that time may not necessarily be harmful, at least for vision.
Bavelier is now taking what she has learned with her video game research and collaborating with a consortium of researchers to look into treatments for amblyopia, a problem caused by poor transmission of the visual image to the brain.
This research was funded by the National Eye Institute and the Office of Naval Research.
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Adapted from materials provided by University of Rochester, via EurekAlert!, a service of AAAS.

Food Choices Evolve Through Information Overload

Just as information overload leads to people repeatedly choosing what they know, same concept applies equally to hundreds of animal species, too, new research shows

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Ever been so overwhelmed by a huge restaurant menu that you end up choosing an old favourite instead of trying something new?

Psychologists have long since thought that information overload leads to people repeatedly choosing what they know. Now, new research has shown that the same concept applies equally to hundreds of animal species, too.

Researchers from the University of Leeds have used computer modelling to examine the evolution of specialisation, casting light on why some animal species have evolved to eat one particular type of food. For example some aphids choose to eat garden roses, but not other plants which would offer similar nutritional values.
"This is a major leap forward in our understanding of the way in which animals interact with their environment," says lead researcher Dr Colin Tosh from the University's Faculty of Biological Sciences. "Our computer models show the way in which neural networks operate in different environments. They have made it possible for us to see how different species make decisions, based on what's happening – or in this case, which foods are available - around them."
Despite the prevalence of specialisation in the animal kingdom, very little is known about why it occurs. The work conducted at Leeds has provided strong evidence in support of the 'neural limitations' hypothesis put forward by academics in the 1990s. This hypothesis, derived from human psychology, is based on the concept of information overload.
"There are several hypotheses to explain specialisation: one suggests that animals adapt to eat certain foods and this prevents them from eating other types of food," says Dr Tosh.
"For example, cows have evolved flat teeth which allow them to chew grass but they are unable to efficiently process meat. However, the problem with these hypotheses is that they don't apply across the board. Some species – such as many plant eating insects – have evolved to specialise even though there are many other available foods they could eat perfectly well."
This is the first study to provide a realistic representation of neural information processing in animals and how these interact with their environment. The research team believe that it could also have major implications for predicting the effects of environmental change.
"A good example of a struggling specialist is the giant panda, which relies on high mountain bamboo," says Dr Tosh. "In understanding how neural processes work, we may be able to gain an insight into how future environmental conditions – such as the dying out of particular types of plants - may affect a range of different animal species that utilise them for food."
This research was funded by the Natural Environment Research Council in the UK.
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Adapted from materials provided by University of Leeds, viaEurekAlert!, a service of AAAS.

Teenage Boys Who Eat Fish At Least Once A Week Achieve Higher Intelligence Scores

New research has found that 15-year-old males who ate fish at least once a week displayed higher cognitive skills at the age of 18 than those who it ate it less frequently.

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Fifteen-year-old males who ate fish at least once a week displayed higher cognitive skills at the age of 18 than those who it ate it less frequently, according to a study of nearly 4,000 teenagers published in the March issue of Acta Paediatrica.
Eating fish once a week was enough to increase combined, verbal and visuospatial intelligence scores by an average of six per cent, while eating fish more than once a week increased them by just under 11 per cent.
Swedish researchers compared the responses of 3,972 males who took part in the survey with the cognitive scores recorded in their Swedish Military Conscription records three years later.

"We found a clear link between frequent fish consumption and higher scores when the teenagers ate fish at least once a week" says Professor Kjell Torén from the Sahlgrenska Academy at the University of Gothenburg, one of the senior scientists involved in the study. "When they ate fish more than once a week the improvement almost doubled.
"These findings are significant because the study was carried out between the ages of 15 and 18 when educational achievements can help to shape the rest of a young man's life."
The research team found that:

• • 58 per cent of the boys who took part in the study ate fish at least once a week and a further 20 per cent ate fish more than once a week.
• • When male teenagers ate fish more than once a week their combined intelligence scores were on average 12 per cent higher than those who ate fish less than once a week. Teenagers who ate fish once a week scored seven per cent higher.
• • The verbal intelligence scores for teenagers who ate fish more than once a week were on average nine per cent higher than those who ate fish less than once a week. Those who ate fish once a week scored four per cent higher.
• • The same pattern was seen in the visuospatial intelligence scores, with teenagers who ate fish more than once a week scoring on average 11 per cent higher than those who ate fish less than once a week. Those who ate fish once a week scored seven per cent higher.

"A number of studies have already shown that fish can help neurodevelopment in infants, reduce the risk of impaired cognitive function from middle age onwards and benefit babies born to women who ate fish during pregnancy" says Professor Torén.

"However we believe that this is the first large-scale study to explore the effect on adolescents."
The exact mechanism that links fish consumption to improved cognitive performance is still not clear.
"The most widely held theory is that it is the long-chain polyunsaturated fatty acids found in fish that have positive effects on cognitive performance" explains Professor Torén.
"Fish contains both omega-3 and omega-6 fatty acids which are known to accumulate in the brain when the foetus is developing. Other theories have been put forward that highlight their vascular and anti-inflammatory properties and their role in suppressing cytokines, chemicals that can affect the immune system."
In order to isolate the effect of fish consumption on the study subjects, the research team looked at a wide range of variables, including ethnicity, where they lived, their parents' educational level, the teenagers' well-being, how frequently they exercised and their weight.
"Having looked very carefully at the wide range of variables explored by this study it was very clear that there was a significant association between regular fish consumption at 15 and improved cognitive performance at 18" concludes lead author Dr Maria Aberg from the Centre for Brain Repair and Rehabilitation at the University of Gothenburg.
"We also found the same association between fish and intelligence in the teenagers regardless of their parents' level of education."
The researchers are now keen to carry out further research to see if the kind of fish consumed - for example lean fish in fish fingers or fatty fish such as salmon - makes any difference to the results.
"But for the time being it appears that including fish in a diet can make a valuable contribution to cognitive performance in male teenagers" says Dr Aberg.
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Adapted from materials provided by Wiley-Blackwell, viaEurekAlert!, a service of AAAS.

Molecular Motors In Cells Work Together, Study Shows

Jeneva Laib, Robert Bloodgood and William Guilford.

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Even within cells, the left hand knows what the right hand is doing. Molecular motors, the little engines that power cell mobility and the ability of cells to transport internal cargo, work together and in close coordination, according to a new finding by researchers at the University of Virginia. The work could have implications for the treatment of neurodegenerative disorders.
"We found that molecular motors operate in an amazingly coordinated manner when moving an algal cell one way or the other," said Jeneva Laib, the lead author and an undergraduate biomedical engineering student at the University of Virginia. "This provides a new understanding of the ways cells move."

The finding appears online in the current issue of The Proceedings of the National Academy of Sciences.
Laib, a second-year student from Lorton, Va., and her collaborators, U.Va. professors Robert Bloodgood and William Guilford, used the alga Chlamydomonas as a model to study how molecular motors in most types of cells work to move internal cargo, such as organelles associated with energy production and nutrient transport, or even the entire cell.
These motions are caused by a line of motors that pull the cell along, like the locomotive on a train. Previous studies had suggested that these motors pulled in opposite directions, like a game of tug of war. More recent studies indicated that the motors were working together rather than independently.
The new U.Va. study provides strong evidence that the motors are indeed working in coordination, all pulling in one direction, as if under command, or in the opposite direction — again, as if under strict instruction.
"We've found that large numbers of these molecular motors are turning on at the same time to generate large amounts of force, and then turning off at the same time to allow transport in the particular direction," said Guilford, Laib's adviser and lab director. "This insight opens up the possibility for us to begin to understand the mechanism that instructs the motors to pull one way or the other."
A greater understanding of cell motility and the ways in which cells move cargo within cells could eventually lead to therapies for neurodegenerative disorders such as amyotrophic lateral sclerosis (Lou Gehrig's Disease), diabetic neuropathy, and Usher syndrome, a progressive loss of hearing and vision. Neurodegenerative diseases can be caused by defects in the transport processes within neural cells.
"You basically get a logjam within the cell that prevents forward progress of these motors and their cargo," Guilford said. "So if we could understand how the motors are normally coordinated inside cells, we might be able to eventually realize therapeutic approaches to restoring transport for cell revival."
"There is some amazing cooperation going on among these motors," noted Bloodgood, a specialist in cell locomotion research. "When one set of as many as 10 motors turn on, another set turns off in unison. Understanding this process could help us to restore this locomotion when defects occur."
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Adapted from materials provided by University of Virginia.

When Texting, Eligible Women Express Themselves Better

Indiana researchers have found that when men and women text message each other in a public, interactive dating market, it is the women who use more non-standard, expressive language techniques.

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The book Men Are from Mars, Women Are from Venus and its gender stereotypes on how the sexes communicate remains fodder for debate, but two Indiana University researchers have confirmed one thing: When men and women talk through technology, it's the women who are more expressive.
Indiana researchers have found that when men and women text message each other in a public, interactive dating market, it is the women who use more non-standard, expressive language techniques.
In an article in the latest edition of the quarterly journal Written Communication, IU researchers Susan Herring and Asta Zelenkauskaite show that while men historically talk more in public settings, when the exchanges occur via text messaging in a public venue -- in this case, Italy's real-time interactive music television channel Allmusic -- it is the women who push their messages closest to the character-count limit, who use more abbreviations and insertions, and who implement more emoticons (like smiling and frowning faces).

"The messages are very flirtatious and have nothing to do with the television show," said Herring, a professor in the IU School of Library and Information Science. "In the linguistic marketplace there have always been different values associated with standard and non-standard language, and here we have found results that are paradoxical, that are the opposite of the recognized socio-linguistic gender patterns."
Women use standard language more than men, in part because it is seen as a type of symbolic currency used to acquire upward mobility, the preponderance of research has shown.
"Women have historically used standard language when they are social aspirers, or want to be perceived as above their station," Herring said. "Men talk more; women are more polite."
But that historical footnote falls apart under the influence of computer-mediated communication such as short message services (SMS) and text messaging, the researchers found, after looking at 1,164 gender-defined messages posted on-screen during the real-time Italian music video program.
Expecting findings consistent with past research on gender-patterned public communication, Herring and Zelenkauskaite were predicting men would post more and longer text messages, and that men would also employ more non-standard techniques. Instead, the opposite was true when it came to communication within a new, convergent medium that mixes interactive television (iTV) with SMS or texting.
The study found women used more non-standard language such as abbreviations or expressive insertions that represented characteristics including enthusiasm, sadness, emphasis and individuality. And while women were both more economical and expressive, they also came closer to maxing out, or did max out, on the 160-character message limit more often than their male counterparts.
"Since iTV is based on texting, which was marketed extensively in Europe, it is extremely popular," said Zelenkauskaite, a doctoral student and native of Lithuania who has spent more than two years studying at Italian universities. "Since cell phones in Italy experience some of the highest levels of penetration in Europe, it is an ideal country to study iTV."
Now the researchers say they want to explore whether they could identify similar amounts and types of non-standard language in text-messaging when different topics available for interactive, public discussion -- like politics or news-oriented programming -- are studied.
"There are news shows in Europe where viewers can comment through iTV but we have not analyzed any of those yet," Herring said. "There are different linguistic marketplaces, and politics is one of them, just like dating is."
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Adapted from materials provided by Indiana University.

Mixed Population Provides Insights Into Human Genetic Makeup

These are three-dimensional images of a face with location points indicated.

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Genetic diseases and genetically mixed populations can help researchers understand human diversity and human origins according to a Penn State physical anthropologist.
"We wanted to get to a strategy to predict what a face will look like," said Mark D. Shriver, associate professor of biological anthropology. "We want to understand the path of evolution that leads to that part of the selection process."
To pinpoint genes that influence the shape of the human face and head, Shriver began with an online database of genes linked to disease -- Online Mendelian Inheritance of Man. If the symptoms of the disease involved the face or skull the gene implicated in the disease became a candidate for those facial traits.

This approach works because although Shriver looked at genes implicated in disease, those same genes in a healthy person may also influence the same physical trait -- length, width, shape, size -- but within the range normal for healthy individuals. Facial traits vary among humans, but do tend to group by population. For example, in general, West Africans have wider faces than Europeans and Europeans have longer faces than West Africans.
"There is a strong relationship between genetic ancestry and facial traits," said Shriver. "Using individuals of combined ancestry, European and African, we can see how the target genes alter facial traits," he told attendees at the 2009 Annual Meeting of the American Association for the Advancement of Science.
The researchers looked at a combined sample of African Americans with West African and European ancestry whose genetic makeup was known through DNA testing. To make it simpler, anyone with Native American ancestry was eliminated so that only two genetic pools were represented -- West African and European. The researchers reported on a sample of 254 individuals using three-dimensional imaging and measured the distances between specific portions of the face. Each individual had provided a DNA sample.
"We started with 22 landmarks on the faces that could be accurately located in all the images," said Shriver.
These landmarks might be the tip of the nose, the tip of the chin, the outer corner of the eye or other repeatable locations. They then recorded the distances between all the points in all directions, so they had a distance map of each of the faces.
From their DNA profiles, Shriver could determine the admixture percentages of each individual, how much of their genetic make up came from each group. He could then compare the genetically determined admixture to the facial feature differences and determine the relative differences from the parental populations.
"This type of study, done on admixed populations shows that each person is a composite of their ancestors and that the range of facial features is a continuum," says Shriver.
Shriver found that there was a very strong statistical correlation between the amounts of admixture and the facial traits.
"We chose to look at African Americans because they were a large enough and available admixed population," said Shriver. "We are trying to solidify our understanding of the origins of humans and the evolutionary processes. Looking at admixed populations shows us the influence genes have and how they relate to physical features."
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Adapted from materials provided by Penn State.

Buying Experiences, Not Possessions, Leads To Greater Happiness

A new study demonstrates that experiential purchases, such as a meal out or theater tickets, result in increased well-being because they satisfy higher order needs, specifically the need for social connectedness and vitality -- a feeling of being alive.

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Can money make us happy if we spend it on the right purchases? A new psychology study suggests that buying life experiences rather than material possessions leads to greater happiness for both the consumer and those around them.
The study demonstrates that experiential purchases, such as a meal out or theater tickets, result in increased well-being because they satisfy higher order needs, specifically the need for social connectedness and vitality -- a feeling of being alive.

"These findings support an extension of basic need theory, where purchases that increase psychological need satisfaction will produce the greatest well-being," said Ryan Howell, assistant professor of psychology at San Francisco State University.
Participants in the study were asked to write reflections and answer questions about their recent purchases. Participants indicated that experiential purchases represented money better spent and greater happiness for both themselves and others. The results also indicate that experiences produce more happiness regardless of the amount spent or the income of the consumer.
Experiences also lead to longer-term satisfaction. "Purchased experiences provide memory capital," Howell said. "We don't tend to get bored of happy memories like we do with a material object.
"People still believe that more money will make them happy, even though 35 years of research has suggested the opposite," Howell said. "Maybe this belief has held because money is making some people happy some of the time, at least when they spend it on life experiences."
"The mediators of experiential purchases: Determining the impact of psychological need satisfaction" was conducted by Ryan Howell, assistant professor of psychology at San Francisco State University and SF State graduate Graham Hill.
These findings will be presented at the Society for Personality and Social Psychology annual meeting on Feb. 7.
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Adapted from materials provided by San Francisco State University, via EurekAlert!, a service of AAAS.

Why Sleep Is Needed To Form Memories

The world as the brain sees it. Optical 'polar' maps of the visual cortex are generated by measuring micro-changes in blood oxygenation as the left eye (left panel) or right eye is stimulated by bars of light of different orientations (0-180 degrees). The cortical response to each stimulus is pseudo-colored to represent the orientation that best activates visual cortical neurons. If vision is blocked in an eye (the right eye in this example) during a critical period of development, neurons no longer respond to input from the deprived eye pathway (indicated by a loss of color in the right panel) and begin to respond preferentially to the non-deprived eye pathway. These changes are accompanied by alterations in synaptic connections in single neurons. This process, known as ocular dominance plasticity, is enhanced by sleep via activation of NMDA receptors and intracellular kinase activity. Through these mechanisms, sleep strengthens synaptic connections in the non-deprived eye pathway.

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If you ever argued with your mother when she told you to get some sleep after studying for an exam instead of pulling an all-nighter, you owe her an apology, because it turns out she's right. And now, scientists are beginning to understand why.
In research published recently in Neuron, Marcos Frank, PhD, Assistant Professor of Neuroscience, at the University of Pennsylvania School of Medicine, postdoctoral researcher Sara Aton, PhD, and colleagues describe for the first time how cellular changes in the sleeping brain promote the formation of memories.

"This is the first real direct insight into how the brain, on a cellular level, changes the strength of its connections during sleep," Frank says.
The findings, says Frank, reveal that the brain during sleep is fundamentally different from the brain during wakefulness.
"We find that the biochemical changes are simply not happening in the neurons of animals that are awake," Frank says. "And when the animal goes to sleep it's like you’ve thrown a switch, and all of a sudden, everything is turned on that's necessary for making synaptic changes that form the basis of memory formation. It's very striking."
The team used an experimental model of cortical plasticity – the rearrangement of neural connections in response to life experiences. "That's fundamentally what we think the machinery of memory is, the actual making and breaking of connections between neurons,” Frank explains
In this case, the experience Frank and his team used was visual stimulation. Animals that were young enough to still be establishing neural networks in response to visual cues were deprived of stimulation through one eye by covering that eye with a patch. The team then compared the electrophysiological and molecular changes that resulted with control animals whose eyes were not covered. Some animals were studied immediately following the visual block, while others were allowed to sleep first.
From earlier work, Frank's team already knew that sleep induced a stronger reorganization of the visual cortex in animals that had an eye patch versus those that were not allowed to sleep. Now they know why.

A molecular explanation is emerging. The key cellular player in this process is a molecule called N-methyl D-aspartate receptor (NMDAR), which acts like a combination listening post and gate-keeper. It both receives extracellular signals in the form of glutamate and regulates the flow of calcium ions into cells.
Essentially, once the brain is triggered to reorganize its neural networks in wakefulness (by visual deprivation, for instance), intra- and intercellular communication pathways engage, setting a series of enzymes into action within the reorganizing neurons during sleep.
To start the process, NMDAR is primed to open its ion channel after the neuron has been excited. The ion channel then opens when glutamate binds to the receptor, allowing calcium into the cell. In turn, calcium, an intracellular signaling molecule, turns other downstream enzymes on and off.
Some neural connections are strengthened as a result of this process, and the result is a reorganized visual cortex. And, this only happens during sleep.
“To our amazement, we found that these enzymes never really turned on until the animal had a chance to sleep," Frank explains, "As soon as the animal had a chance to sleep, we saw all the machinery of memory start to engage." Equally important was the demonstration that inhibition of these enzymes in the sleeping brain completely prevented the normal reorganization of the cortex.
Frank stresses that this study did not examine recalling memories. For example, these animals were not being asked to remember the location of their food bowl. "It's a mechanism that we think underlies the formation of memory.” And not only memory; the same mechanism could play a role in all neurological plasticity processes.
As a result, this study could pave the way to understanding, on a molecular level, why humans need sleep, and why they are so affected by the lack of it. It could also conceivably lead to novel therapeutics that could compensate for the lack of sleep, by mimicking the molecular events that occur during sleep.
Finally, the study could lead to a deeper understanding of human memory. Though how and even where humans store long-lasting memories remains a mystery, Frank says, "we do know that changes in cortical connections is at the heart of the mystery. By understanding that in animal models, it will bring us close to understanding how it works in humans."
The research was funded by the National Institutes of Health, the National Sleep Foundation, and L'Oreal USA, and also involved researchers at the Penn’s Center for Sleep and Respiratory Neurobiology, and the School of Life Sciences, Jawaharlal Nehru University, New Delhi, India.
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Adapted from materials provided by University of Pennsylvania School of Medicine.

High Hormone Levels In Women May Lead To Infidelity, Study Shows

"The researchers found that a woman's oestradiol level (sex hormone level) was positively associated with self-perceived physical attractiveness. Women with a higher oestradiol level also reported a greater likelihood of flirting, kissing and having a serious affair (but not a one-night stand) with a new partner."

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Women with high levels of the sex hormone oestradiol may engage in opportunistic mating, according to a new study by psychology researchers at The University of Texas at Austin.

Doctoral candidate Kristina Durante and Assistant Professor of Psychology Norm Li published their findings in the Proceedings of the Royal Society of London: Biology Letters.

"The study offers further evidence that physiological mechanisms continue to play a major role in guiding women's sexual motivations and behavior," Durante said.
Durante and Li investigated the relationship between oestradiol, an ovarian hormone linked to fertility, and sexual motivation in a study of 52 female undergraduates not using contraception. Participants' ages ranged from 17 to 30 years old.
The researchers measured the participants' hormone levels at two points during each woman's ovulatory cycle and then asked them to rate their own physical attractiveness. Independent observers also rated the participants' physical attractiveness.
Participants also answered survey questions that measured their propensity to cheat on a partner.
The researchers found that a woman's oestradiol level was positively associated with self-perceived physical attractiveness. Women with a higher oestradiol level also reported a greater likelihood of flirting, kissing and having a serious affair (but not a one-night stand) with a new partner.
Oestradiol levels were negatively associated with a woman's satisfaction with her primary partner.
"Our findings show that highly fertile women are not easily satisfied by their long-term partners and are motivated to seek out more desirable partners," Durante explained. "However, that doesn't mean they're more likely to engage in casual sex. Instead, they adopt a strategy of serial monogamy".

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Adapted from materials provided by University of Texas.