• Received June 16, 2011.
• Accepted November 21, 2011.

Age-related delays in neural timing are not inevitable and can be avoided or offset with musical training, according to a new study from Northwestern University. The study is the first to provide biological evidence that lifelong musical experience has an impact on the aging process.

“The older musicians not only outperformed their older non-musician counterparts, they encoded the sound stimuli as quickly and accurately as the younger non-musicians,” said Northwestern neuroscientist Nina Kraus. “This reinforces the idea that how we actively experience sound over the course of our lives has a profound effect on how our nervous system functions.”

Kraus, professor of communication sciences in the School of Communication and professor of neurobiology and physiology in the Weinberg College of Arts and Sciences, is co-author of “Musical experience offsets age-related delays in neural timing” published online in the journal Neurobiology of Aging.

“These are very interesting and important findings,” said Don Caspary, a nationally known researcher on age-related hearing loss at Southern Illinois University School of Medicine. “They support the idea that the brain can be trained to overcome, in part, some age-related hearing loss.”

“The new Northwestern data, with recent animal data from Michael Merzenich and his colleagues at University of California, San Francisco, strongly suggest that intensive training even late in life could improve speech processing in older adults and, as a result, improve their ability to communicate in complex, noisy acoustic environments,” Caspary added.

Previous studies from Kraus’ Auditory Neuroscience Laboratory suggest that musical training also offset losses in memory and difficulties hearing speech in noise — two common complaints of older adults. The lab has been extensively studying the effects of musical experience on brain plasticity across the life span in normal and clinical populations, and in educational settings.

However, Kraus warns that the current study’s findings were not pervasive and do not demonstrate that musician’s have a neural timing advantage in every neural response to sound. “Instead, this study showed that musical experience selectively affected the timing of sound elements that are important in distinguishing one consonant from another.”

The automatic neural responses to speech sounds delivered to 87 normal-hearing, native English-speaking adults were measured as they watched a captioned video. “Musician” participants began musical training before age 9 and engaged consistently in musical activities through their lives, while “non-musicians” had three years or less of musical training.

The above story is reprinted from materials provided by Northwestern University. The original article was written by Wendy Leopold.

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1. Alexandra Parbery-Clark, Samira Anderson, Emily Hittner, Nina Kraus. Musical experience offsets age-related delays in neural timing. Neurobiology of Aging, 2012; DOI: 10.1016/j.neurobiolaging.2011.12.015

A study recently published in Nature Genetics has found new evidence for a link between the body clock hormone melatonin and type 2 diabetes. The study found that people who carry rare genetic mutations in the receptor for melatonin have a much higher risk of type 2 diabetes.

Previous research has found that people who work night shifts have a higher risk of type 2 diabetes and heart disease. Studies have also found that if volunteers have their sleep disrupted repeatedly for three days, they temporarily develop symptoms of diabetes.

The body’s sleep-wake cycle is controlled by the hormone melatonin, which has effects including drowsiness and lowering body temperature. In 2008, a genetic study led by Imperial College London discovered that people with common variations in the gene for MT2, a receptor for melatonin, have a slightly higher risk of type 2 diabetes.

The new study reveals that carrying any of four rare mutations in the MT2 gene increases a person’s risk of developing type 2 diabetes six times. The release of insulin, which regulates blood sugar levels, is known to be regulated by melatonin. The researchers suggest that mutations in the MT2 gene may disrupt the link between the body clock and insulin release, leading to abnormal control of blood sugar.

Professor Philippe Froguel, from the School of Public Health at Imperial College London, who led the study, said: “Blood sugar control is one of the many processes regulated by the body’s biological clock. This study adds to our understanding of how the gene that carries the blueprint for a key component in the clock can influence people’s risk of diabetes.

“We found very rare variants of the MT2 gene that have a much larger effect than more common variants discovered before. Although each mutation is rare, they are common in the sense that everyone has a lot of very rare mutations in their DNA. Cataloguing these mutations will enable us to much more accurately assess a person’s risk of disease based on their genetics.”

In the study, the Imperial team and their collaborators at several institutions in the UK and France examined the MT2 gene in 7,632 people to look for more unusual variants that have a bigger effect on disease risk. They found 40 variants associated with type 2 diabetes, four of which were very rare and rendered the receptor completely incapable of responding to melatonin. The scientists then confirmed the link with these four variants in an additional sample of 11,854 people.

Professor Froguel and his team analysed each mutation by testing what effect they have on the MT2 receptor in human cells in the lab. The mutations that completely prevented the receptor from working proved to have a very big effect on diabetes risk, suggesting that there is a direct link between MT2 and the disease.

The research was funded by the Wellcome Trust, the National Institute for Health Research and the Medical Research Council in the UK and the Agence National de la Recherche, the Contrat de Projets Etat-Région Nord-Pas-De-Calais, the Société Francophone du Diabète, the Fondation Recherche Médicale and the Centre National de la Recherche Scientifique in France.

The above story is reprinted from materials provided by Imperial College London, via AlphaGalileo.

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1. Amélie Bonnefond, Nathalie Clément, Katherine Fawcett, Loïc Yengo, Emmanuel Vaillant, Jean-Luc Guillaume, Aurélie Dechaume, Felicity Payne, Ronan Roussel, Sébastien Czernichow, Serge Hercberg, Samy Hadjadj, Beverley Balkau, Michel Marre, Olivier Lantieri, Claudia Langenberg, Nabila Bouatia-Naji, Guillaume Charpentier, Martine Vaxillaire, Ghislain Rocheleau, Nicholas J Wareham, Robert Sladek, Mark I McCarthy, Christian Dina, Inês Barroso, Ralf Jockers, Philippe Froguel. Rare MTNR1B variants impairing melatonin receptor 1B function contribute to type 2 diabetes. Nature Genetics, 2012; DOI: 10.1038/ng.1053

Researchers involved in the Mayo Clinic Study of Aging report that more than 6 percent of Americans age 70 to 89 develop mild cognitive impairment (MCI) every year. Also, the condition appears to affect men and those who only have a high school education more than women and those who have completed some higher education. People with MCI are at the stage between suffering the normal forgetfulness associated with aging and developing dementia, such as that caused by Alzheimer’s disease.

The study — published in the Jan. 25, 2012, issue of Neurology, the medical journal of the American Academy of Neurology — reports that 296 of the 1,450 study participants developed MCI, an incidence rate of 6.4 percent per year overall. Among men, the incidence rate was 7.2 percent, compared with 5.7 percent per year for women.

“While incidence rates for MCI have been reported previously, ours is one of the few studies designed specifically to measure the incidence of MCI and its subtypes using published criteria,” says lead author Rosebud O. Roberts, M.B., Ch.B., of the Mayo Clinic Division of Epidemiology. “The statistically significant difference between incidence rates among men and women represents an important finding for those evaluating patients for MCI.”

The study also looked in more detail at patients with MCI, dividing them according to whether they developed amnestic MCI (aMCI) — in which the condition affects the memory domain — or non-amnestic MCI (naMCI).

Similar to the overall results, the incidence rates for aMCI and naMCI were higher in men than in women. In addition, the study found that individuals with only a high school education developed either aMCI or naMCI at a higher rate than those with some higher education.

“Understanding the distribution of incident MCI by age, sex and other demographic variables is critical to helping us understand the cause of the condition, as well as how to prevent MCI and its progression to full-blown, irreversible dementia,” Dr. Roberts says. “This study advances our understanding of MCI and will help clinicians provide even better care for their patients, especially during initial evaluations.”

About Mild Cognitive Impairment

People with MCI have mild problems with thinking and memory that do not interfere with everyday activities, although their forgetfulness is often apparent to them and their friends and family. While not everyone with MCI develops dementia, an estimated 5 to 10 percent do.

Symptoms of MCI include:

• Difficulty learning and remembering new information
• Difficulty solving problems or making decisions
• Forgetting recent events or conversations
• Taking longer to perform complex or difficult mental activities.

The above story is reprinted from materials provided by Mayo Clinic, via Newswise.

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1. R. O. Roberts, Y. E. Geda, D. S. Knopman, R. H. Cha, V. S. Pankratz, B. F. Boeve, E. G. Tangalos, R. J. Ivnik, W. A. Rocca, R. C. Petersen. The incidence of MCI differs by subtype and is higher in men: The Mayo Clinic Study of Aging. Neurology, 2012; DOI: 10.1212/WNL.0b013e3182452862

Extra-virgin olive oil can protect the liver from oxidative stress. Researchers writing in BioMed Central’s open access journal Nutrition and Metabolism exposed rats to a moderately toxic herbicide known to deplete antioxidants and cause oxidative stress, finding that those rats fed on a diet containing the olive oil were partially protected from the resulting liver damage.

The researchers separated the rats into a control group, an olive oil group, and 6 groups that were exposed to the herbicide ‘2,4-Dichlorophenoxyacetic acid’ with or without either whole olive oil, or one of two oil extracts — the hydrophilic fraction or the lipophilic fraction. All rats given the herbicide showed signs of significant liver damage. However, extra virgin olive oil and hydrophilic fraction intake induced a significant increase in antioxidant enzyme activity and a decrease in markers of liver damage.

Speaking about the results, Hammami said, “The hydrophilic fraction of olive oil seems to be the effective one in reducing toxin-induced oxidative stress, indicating that hydrophilic extract may exert a direct antioxidant effect on hepatic cells. However, more detailed studies about the effect of antioxidant compounds separately and/or their interactions are necessary to substantiate these observations.”

The above story is reprinted from materials provided by BioMed Central, via EurekAlert!, a service of AAAS.

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1. Amel Nakbi, Wafa Tayeb, Abir Grissa, Manel Issaoui, Samia Dabbou, Issam Chargui, Meriem Ellouz, Abdelhedi Miled and Mohamed Hammami. Effects of olive oil and its fractions on oxidative stress and the liver’s fatty acid composition in 2,4-Dichlorophenoxyacetic acid- treated rats. Nutrition & Metabolism, 2010; (in press) [link]

Eating food fried in olive or sunflower oil is not linked to heart disease or premature death, finds a paper published in the British Medical Journal online (bmj.com).  The authors stress, however, that their study took place in Spain, a Mediterranean country where olive or sunflower oil is used for frying and their results would probably not be the same in another country where solid and re-used oils were used for frying.

In Western countries, frying is one of the most common methods of cooking. When food is fried it becomes more calorific because the food absorbs the fat of the oils.

While eating lots of fried food can increase some heart disease risk factors such as high blood pressure, high cholesterol and obesity, a link between fried food and heart disease has not been fully investigated.

So the authors, led by Professor Pilar Guallar-Castillón from Autonomous University of Madrid, surveyed the cooking methods of 40,757 adults aged 29 to 69 over an 11-year period. None of the participants had heart disease when the study began.

Trained interviewers asked participants about their diet and cooking methods. Fried food was defined as food for which frying was the only cooking method used. Questions were also asked about whether food was fried, battered, crumbed or sautéed.

The participants’ diet was divided into ranges of fried food consumption, the first quartile related to the lowest amount of fried food consumed and the fourth indicated the highest amount.

During the follow-up there were 606 events linked to heart disease and 1,134 deaths.

The authors conclude: “In a Mediterranean country where olive and sunflower oils are the most commonly used fats for frying, and where large amounts of fried foods are consumed both at and away from home, no association was observed between fried food consumption and the risk of coronary heart disease or death.”

In an accompanying editorial, Professor Michael Leitzmann from the University of Regensburg in Germany, says the study explodes the myth that “frying food is generally bad for the heart” but stresses that this “does not mean that frequent meals of fish and chips will have no health consequences.” He adds that specific aspects of frying food are relevant, such as the type of oil used.

The above story is reprinted from materials provided by BMJ-British Medical Journal.

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1. P. Guallar-Castillon, F. Rodriguez-Artalejo, E. Lopez-Garcia, L. M. Leon-Munoz, P. Amiano, E. Ardanaz, L. Arriola, A. Barricarte, G. Buckland, M.-D. Chirlaque, M. Dorronsoro, J.-M. Huerta, N. Larranaga, P. Marin, C. Martinez, E. Molina, C. Navarro, J. R. Quiros, L. Rodriguez, M. J. Sanchez, C. A. Gonzalez, C. Moreno-Iribas. Consumption of fried foods and risk of coronary heart disease: Spanish cohort of the European Prospective Investigation into Cancer and Nutrition study. BMJ, 2012; 344 (jan23 3): e363 DOI: 10.1136/bmj.e363
2. M. F. Leitzmann, T. Kurth. Fried foods and the risk of coronary heart disease. BMJ, 2012; 344 (jan23 3): d8274 DOI: 10.1136/bmj.d8274

A pilot study suggests infrared analysis of white blood cells is a promising strategy for diagnosis of Alzheimer’s disease. Spanish researchers, led by Pedro Carmona from the Instituto de Estructura de la Materia in Madrid, have uncovered a new promising way to diagnose Alzheimer’s disease more accurately. Their technique, which is non-invasive, fast and low-cost, measures how much infrared radiation is either emitted or absorbed by white blood cells. Because of its high sensitivity, this method is able to distinguish between the different clinical stages of disease development thereby allowing reliable diagnosis of both mild and moderate stages of Alzheimer’s.

The work is published online in Springer’s journal Analytical & Bioanalytical Chemistry.

Alzheimer’s disease is the most common form of adult onset dementia and is characterized by the degeneration of the nervous system. In particular, as the disease progresses, the amount of amyloid-ß peptide in the body rises. At present, the most reliable and sensitive diagnostic techniques are invasive, e.g. require analysis of cerebrospinal fluid (the liquid that surrounds the brain and spinal cord). However, white blood cells (or mononuclear leukocytes) are also thought to carry amyloid-ß peptide in Alzheimer patients.

The researchers used two-dimensional infrared spectroscopy to measure and compare the infrared radiation emitted or absorbed by white blood cells of healthy controls, versus those of patients with mild, moderate and severe Alzheimer’s disease. A total of 50 patients with Alzheimer’s and 20 healthy controls took part in the study and gave blood samples.

The authors found significant differences in the range of infrared wavelengths displayed between subjects, which were attributable to the different stages of formation of amyloid-ß structures in the blood cells. The results showed that, with this method, healthy controls could be distinguished from mild and moderate sufferers of Alzheimer’s disease. The method is being explored as a tool for early diagnosis.

The authors conclude: “The method we used can potentially offer a more simple detection of alternative biomarkers of Alzheimer’s disease. Mononuclear leukocytes seem to offer a stable medium to determine ß-sheet structure levels as a function of disease development. Our measurements seem to be more sensitive for earlier stages of Alzheimer’s disease, namely mild and moderate.”

The above story is reprinted from materials provided by Springer Science+Business Media.

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1. Pedro Carmona, Marina Molina, Miguel Calero, Félix Bermejo-Pareja, Pablo Martínez-Martín, Isabel Alvarez, Adolfo Toledano. Infrared spectroscopic analysis of mononuclear leukocytes in peripheral blood from Alzheimer’s disease patients. Analytical and Bioanalytical Chemistry, 2012; DOI: 10.1007/s00216-011-5669-9

A study by academics at Northumbria University has shown for the first time that trekking-poles help hikers maintain muscle function while significantly reducing soreness in the days following a hike. In the study, 37 physically active men and women were split into two groups of equal fitness and asked to hike up and down Snowdon, the highest mountain in England and Wales.

One group was issued with and trained in the use of trekking poles while the other group made the climb unaided. Each group ate the same evening meal on the night before; they ate the same breakfast, carried similar weight in day packs and took the same scheduled rests during both the ascent and descent.

The participants’ heart rates and their personal perceived exertion ratings were recorded during the hike. Then, at the end of the hike, and at 24-, 48- and 72-hour intervals afterwards, muscle damage and function were assessed through a variety of tests.

The results showed that there was significantly less muscle soreness in the group using trekking poles. This group demonstrated a reduced loss of strength and a faster recovery immediately after the trek compared to the control group. Self-rated soreness peaked at 24-hours in both groups but was significantly lower in the trekking-pole group, both at this point and at the 48-hour point. In addition, levels of the enzyme creatine kinase (which indicates muscle damage) were much higher at the 24-hour point in the non-pole group, while the trekking-pole group’s levels were close to the pre-trekking levels. This shows that the muscle damage they were experiencing was negligible.

Pole manufacturers have suggested that trekking poles can reduce forces on lower-limb joints by as much as 25 %. However, the existing research has been restricted to the laboratory or to non-mountainous outdoor settings, such as running tracks, and has only focussed on biomechanical investigations into stress on the ankle, knee and hip. This is the first documented study into the effectiveness of trekking poles in the environments for which they were designed.

“The results present strong evidence that trekking poles reduce, almost to the point of complete disappearance, the extent of muscle damage during a day’s mountain trek,” says Dr Glyn Howatson, who conducted the study.

“Preventing muscle damage and soreness is likely to improve motivation and so keep people enjoying the benefits of exercise for longer. Perhaps even more advantageously, the combined benefits of using trekking poles in reducing load to the lower limbs, increasing stability and reducing muscle damage could also help avoid injury on subsequent days trekking. It is often the reduced reaction time and position sense, associated with damaged muscles that cause the falls and trips that can lead to further injury in mountainous or uneven terrain.

“These findings have particularly strong application for exercisers wishing to engage in consecutive days’ activity in mountainous terrain.”

The above story is reprinted from materials provided by Northumbria University, via AlphaGalileo.

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Protein — not sugar — stimulates cells keeping us thin and awake, a new study suggests. A new study has found that protein and not sugar activates the cells responsible for keeping us awake and burning calories. The research, published in the Nov. 17 issue of the scientific journal Neuron, has implications for understanding obesity and sleep disorders.

Wakefulness and energy expenditure rely on “orexin cells,” which secrete a stimulant called orexin/hypocretin in the brain. Reduced activity in these unique cells results in narcolepsy and has been linked to weight gain.

Scientists at the University of Cambridge compared actions of different nutrients on orexin cells. They found that amino acids — nutrients found in proteins such as egg whites — stimulate orexin neurons much more than other nutrients.

“Sleep patterns, health, and body weight are intertwined. Shift work, as well as poor diet, can lead to obesity,” said lead researcher Dr Denis Burdakov of the Department of Pharmacology and Institute of Metabolic Science. “Electrical impulses emitted by orexin cells stimulate wakefulness and tell the body to burn calories. We wondered whether dietary nutrients alter those impulses.”

To explore this, the scientists highlighted the orexin cells (which are scarce and difficult to find) with genetically targeted fluorescence in mouse brains. They then introduced different nutrients, such as amino acid mixtures similar to egg whites, while tracking orexin cell impulses.

They discovered that amino acids stimulate orexin cells. Previous work by the group found that glucose blocks orexin cells (which was cited as a reason for after-meal sleepiness), and so the researchers also looked at interactions between sugar and protein. They found that amino acids stop glucose from blocking orexin cells (in other words, protein negated the effects of sugar on the cells).

These findings may shed light on previously unexplained observations showing that protein meals can make people feel less calm and more alert than carbohydrate meals.

“What is exciting is to have a rational way to ‘tune’ select brain cells to be more or less active by deciding what food to eat,” Dr Burdakov said. “Not all brain cells are simply turned on by all nutrients, dietary composition is critical.

“To combat obesity and insomnia in today’s society, we need more information on how diet affects sleep and appetite cells. For now, research suggests that if you have a choice between jam on toast, or egg whites on toast, go for the latter! Even though the two may contain the same number of calories, having a bit of protein will tell the body to burn more calories out of those consumed.”

1. Mahesh M. Karnani, John Apergis-Schoute, Antoine Adamantidis, Lise T. Jensen, Luis de Lecea, Lars Fugger, Denis Burdakov. Activation of Central Orexin/Hypocretin Neurons by Dietary Amino Acids. Neuron, 2011; 72 (4): 616 DOI: 10.1016/j.neuron.2011.08.027

There is no doubt that eating a balanced diet is essential for maintaining a healthy body weight as well as appropriate arousal and energy balance, but the details about how the nutrients we consume are detected and processed in the brain remain elusive. Now, a research study discovers intriguing new information about how dietary nutrients influence brain cells that are key regulators of energy balance in the body.

“The nutritional composition of meals, such as the protein:carbohydrate (sugar) ratio has long been recognized to affect levels of arousal and attention,” explains senior study author, Dr. Denis Burdakov, from the University of Cambridge. “However, while certain specialized neurons are known to sense individual nutrients, such as the sugar glucose, it remains unclear how typical dietary combinations of nutrients affect energy balance-regulating brain circuits.”

Dr. Burdakov and colleagues studied how physiological mixtures of nutrients influenced “orexin/hypocretin” neurons, which are known to be critical regulators of wakefulness and energy balance in the body. Previous research had demonstrated that orexin/hypocretin neurons are inhibited by glucose. Surprisingly, the current study revealed that physiologically relevant mixtures of amino acids, the nutrients derived from proteins (such as egg white), stimulated and activated the orexin/hypocretin neurons. The researchers went on to show that when orexin/hypocretin neurons were simultaneously exposed to amino acids and sugars, the amino acids served to suppress the inhibitory influence of glucose.

Taken together, these results support a new and more complex nutrient-specific model for dietary regulation of orexin/hypocretin neurons. “We found that activity in the orexin/hypocretin system is regulated by macronutrient balance rather than simply by the caloric content of the diet, suggesting that the brain contains not only energy-sensing cells, but also cells that can measure dietary balance,” concludes Dr Burdakov. “Our data support the idea that the orexin/hypocretin neurons are under a ‘push-pull’ control by sugars and proteins. Interestingly, although behavioral effects are beyond the scope of our study, this cellular model is consistent with reports that when compared with sugar-rich meals, protein-rich meals are more effective at promoting wakefulness and arousal.”

The above story is reprinted from materials provided by Cell Press, via EurekAlert!, a service of AAAS.

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1. Mahesh M. Karnani, John Apergis-Schoute, Antoine Adamantidis, Lise T. Jensen, Luis de Lecea, Lars Fugger, Denis Burdakov. Activation of Central Orexin/Hypocretin Neurons by Dietary Amino Acids. Neuron, 2011; 72 (4): 616 DOI: 10.1016/j.neuron.2011.08.027