Category: Science News

{Nearly 1 in 4 U.S. citizens gets food poisoning every year, but very few report it. Twitter communications between the public and the proper government authorities could improve foodborne illness reporting as well as the steps that follow, according to a new study from the Brown School at Washington University in St. Louis.}

Jenine Harris, associate professor, and colleagues partnered with the City of St. Louis Department of Health in October 2015 to implement the HealthMap Foodborne Dashboard developed at Boston Children’s Hospital. In the first seven months of the pilot study, they identified 193 tweets relevant to food poisoning and replied with a link to a form for reporting illness to the health department. Nearly 7 percent resulted in a report submission.

“Increasing trust and interaction between government and the public through social media are promising strategies for food safety,” said Harris, lead author of the study, “Using Twitter to Identify and Respond to Food Poisoning: The Food Safety STL Project,” published Feb. 3 in the Journal of Public Health Management and Practice.

“The dashboard technology has potential for improving foodborne illness reporting and can be implemented in other areas to improve response to public health issues such as suicidality, the spread of Zika virus, infection and hospital quality,” Harris said.

Although about 23 percent of the U.S. population uses Twitter, extending the dashboard to other social media could also improve reporting among non-Twitter users, she said.

Source:Science Daily

{These days, it’s a territory mostly dominated by the likes of Raffi and the Wiggles, but there’s new evidence that lullabies, play songs, and other music for babies and toddlers may have some deep evolutionary roots.}

A new theory paper, co-authored by Graduate School of Education doctoral student Samuel Mehr and Assistant Professor of Psychology Max Krasnow, proposes that infant-directed song evolved as a way for parents to signal to children that their needs are being met, while still freeing up parents to perform other tasks, like foraging for food, or caring for other offspring. Infant-directed song might later have evolved into the more complex forms of music we hear in our modern world. The theory is described in an open-access paper in the journal Evolution and Human Behavior.

Music is a tricky topic for evolutionary science: it turns up in many cultures around the world in many different contexts, but no one knows why humans are the only musical species. Noting that it has no known connection to reproductive success, Professor of Psychology Steven Pinker, described it as “auditory cheesecake” in his book How the Mind Works.

“There has been a lot of attention paid to the question of where music came from, but none of the theories have been very successful in predicting the features of music or musical behavior,” Krasnow said. “What we are trying to do with this paper is develop a theory of music that is grounded in evolutionary biology, human life history and the basic features of mammalian ecology.”

At the core of their theory, Krasnow said, is the notion that parents and infants are engaged in an “arms race” over an invaluable resource — attention.

“Particularly in an ancestral world, where there are predators and other people that pose a risk, and infants don’t know which foods are poisonous and what activities are hazardous, an infant can be kept safe by an attentive parent,” he said. “But attention is a limited resource.”

While there is some cooperation in the battle for that resource — parents want to satisfy infants appetite for attention because their cries might attract predators, while children need to ensure parents have time for other activities like foraging for food — that mutual interest only goes so far.

Attention, however, isn’t the only resource to cause such disagreements.

The theory of parent-offspring conflict was first put forth over forty years ago by the evolutionary biologist Robert Trivers, then an Assistant Professor at Harvard. Trivers predicted that infants and parents aren’t on the same page when it comes to the distribution of resources.

“His theory covers everything that can be classified as parental investment,” Krasnow said. “It’s anything that a parent could give to an offspring to help them, or that they may want to hold back for themselves and other offspring.”

Sexual reproduction means that every person gets half of their genes from each parent, but which genes in particular can differ even across full siblings.

Krasnow explains, “A gene in baby has only a fifty percent chance of being found in siblings by virtue of sharing two parents. That means that from the baby’s genetic perspective, she’ll want a more self-favoring division of resources, for example, than her mom or her sister wants, from their genetic perspectives.”

Mehr and Krasnow took the idea of parent-offspring conflict and applied it attention. They predict that children should ‘want’ a greater share of their parents’ attention than their parents ‘want’ to give them. But how does the child know it is has her parent’s attention? The solution, Krasnow said, is that parents were forced to develop some method of signaling to their offspring that their desire for attention was being met.

“I could simply look at my children, and they might have some assurance that I’m attending to them,” Krasnow said. “But I could be looking at them and thinking of something else, or looking at them and focusing on my cell phone, and not really attending to them at all. They should want a better signal than that.”

Why should that signal take the form of a song?

What makes such signals more honest, Mehr and Krasnow think, is the cost associated with them — meaning that by sending a signal to an infant, a parent cannot be sending it to someone else, sending it but lying about it, etc. “Infant directed song has a lot of these costs built in. I can’t be singing to you and be talking to someone else,” Krasnow said. “It’s unlikely I’m running away, because I need to control my voice to sing. You can tell the orientation of my head, even without looking at me, you can tell how far away I am, even without looking.”

Mehr notes that infant-directed song provides lots of opportunities for parents to signal their attention to infants: “Parents adjust their singing in real time, by altering the melody, rhythm, tempo, timbre, of their singing, adding hand motions, bouncing, touching, and facial expressions, and so on. All of these features can be finely tuned to the baby’s affective state — or not. The match or mismatch between baby behavior and parent singing could be informative for whether or not the parent is paying attention to the infant.”

Indeed, it would be pretty odd to sing a happy, bubbly song to a wailing, sleep-deprived infant.

Krasnow agrees. “All these things make something like an infant directed vocalization a good cue of attention,” he continued. “And when you put that into this co-evolutionary arms race, you might end up getting something like infant-directed song. It could begin with something like primitive vocalizations, which gradually become more infant directed, and are elaborated into melodies.”

“If a mutation develops in parents that allows them to do that quicker and better, then they have more residual budget to spend on something else, and that would spread,” he said. “Infants would then be able to get even choosier, forcing parents to get better, and so on. This is the same kind of process that starts with drab birds and results in extravagant peacocks and choosy peahens.” And as signals go, Krasnow said, those melodies can prove to be enormously powerful.

“The idea we lay out with this paper is that infant-directed song and things that share its characteristics should be very good at calming a fussy infant — and there is some evidence of that,” he said. “We’re not talking about going from this type of selection to Rock-a-Bye Baby; this theory says nothing about the words to songs or the specific melodies, it’s saying that the acoustic properties of infant directed song should make it better at calming an infant than other music.”

But, could music really be in our genes?

“A good comparison to make is to language,” Krasnow said. “We would say there’s a strong genetic component to language — we have a capability for language built into our genes — and we think the same thing is going to be true for music.”

What about other kinds of music? Mehr is optimistic that this work could be informative for this question down the road.

“Let’s assume for a moment that the theory is right. How, then, did we get from lullabies to Duke Ellington?” he asked. “The evolution of music must be a complex, multi-step process, with different features developing for different reasons. Our theory raises the possibility that infant-directed song is the starting point for all that, with other musical behaviors either developing directly via natural selection, as byproducts of infant-directed song, or as byproducts of other adaptations.”

For Pinker, the paper differs in one important way from other theories of how music evolves in that it makes evolutionary sense.

“In the past, people have been so eager to come up with an adaptive explanation for music that they have advanced glib and circular theories, such as that music evolved to bond the group,” he said. “This is the first explanation that at least makes evolutionary sense — it shows how the features of music could cause an advantage in fitness. That by itself doesn’t prove that it’s true, but at least it makes sense!”

Source:Science Daily

{Bumblebees can be trained to score goals using a mini-ball, revealing unprecedented learning abilities, according to scientists at Queen Mary University of London (QMUL).}

Their study, published in the journal Science, suggests that species whose lifestyle demands advanced learning abilities could learn entirely new behaviours if there is ecological pressure.

Project supervisor and co-author Professor Lars Chittka from QMUL’s School of Biological and Chemical Sciences, said: “Our study puts the final nail in the coffin of the idea that small brains constrain insects to have limited behavioural flexibility and only simple learning abilities.”

Previous research has shown that bumblebees could solve a range of cognitive tasks, but these have so far resembled tasks similar to the bees’ natural foraging routines, such as pulling strings to obtain food.

This study examines bees’ behavioral flexibility to carry out tasks that are not naturally encountered by the insects.

“We wanted to explore the cognitive limits of bumblebees by testing whether they could use a non-natural object in a task likely never encountered before by any individual in the evolutionary history of bees,” said Dr Clint Perry, joint lead author and also from QMUL’s School of Biological and Chemical Sciences.

The experiment required the bees to move a ball to a specified location to obtain a reward of food. The insects were first trained to know the correct location of the ball on a platform. Subsequently, to obtain their reward, the bees had to move a displaced ball to the specified location.

To learn the technique, the bees were trained under one of three conditions: some observed a previously trained bee move the furthest ball to the centre to gain reward, others received a “ghost” demonstration, where a magnet hidden underneath the platform was used to move the ball, and a third group received no demonstration, where they found the ball already at the centre of the platform with reward.

The bees that observed the technique from a live or model demonstrator learned the task more efficiently than those observing a “ghost” demonstration or without demonstration.

Joint lead author Dr Olli J. Loukola, said: “The bees solved the task in a different way than what was demonstrated, suggesting that observer bees did not simply copy what they saw, but improved on it. This shows an impressive amount of cognitive flexibility, especially for an insect.”

During the demonstrations, the researchers placed three yellow balls at varying distances from the centre. The “demonstrator” bees always moved the furthest ball to the centre, and always from the same spatial location, since they had been trained under conditions where the closer balls were immobile. Untrained bees were given three opportunities to watch a skilled bee perform the task in this manner.

In later tests, when these untrained bees were tested without the presence of a skilled demonstrator, bees moved the closest ball instead of the furthest ball, which they had seen the demonstrator moving. In another experiment, the bees also used a differently coloured ball than previously encountered.

Dr Loukola added: “It may be that bumblebees, along with many other animals, have the cognitive capabilities to solve such complex tasks, but will only do so if environmental pressures are applied to necessitate such behaviours.”

Source:Science Daily

{“Food production must double by 2050 to feed the world’s growing population.” This truism has been repeated so often in recent years that it has become widely accepted among academics, policymakers and farmers, but now researchers are challenging this assertion and suggesting a new vision for the future of agriculture.}

Research published in Bioscience suggests that production likely will need to increase between 25 percent and 70 percent to meet 2050 food demand. The assertion that we need to double global crop and animal production by 2050 is not supported by the data, argues Mitch Hunter, doctoral student in agronomy, in Penn State’s College of Agricultural Sciences. He says the analysis shows that production needs to keep increasing, but not as fast as many have claimed.

However, clarifying future food demand is only part of the story.

“In the coming decades, agriculture will be called upon to both feed people and ensure a healthy environment,” said Hunter. “Right now, the narrative in agriculture is really out of balance, with compelling goals for food production but no clear sense of the progress we need to make on the environment. To get the agriculture we want in 2050, we need quantitative targets for both food production and environmental impacts.”

Specifying quantitative targets, the researchers contend, will clarify the scope of the challenges that agriculture must face in the coming decades, focusing research and policy on achieving specific outcomes.

“Food production and environmental protection must be treated as equal parts of agriculture’s grand challenge,” says study co-author David Mortensen, professor of weed and applied plant ecology, Penn State.

These new findings have important implications for farmers. Lower demand projections may suggest that prices will not rise as much as expected in coming decades. However, the authors note that economic forecasting models already are based on up-to-date quantitative projections, so price forecasts may not be affected greatly by this new analysis.

At the same time, farmers will need to ramp up efforts to hold nutrients on their fields, reduce greenhouse gas emissions and improve soil health.

This analysis builds on the two most commonly cited food-demand projections, one from the United Nations Food and Agriculture Organization and one led by David Tilman, a prominent ecologist at the University of Minnesota. Hunter and his colleagues did not dispute these underlying projections; they simply updated them to help reframe the narrative.

“Both of these projections are credible and important, but the baseline years they used are over a decade past now, and global production has ramped up considerably in that time,” Hunter explained.

So, while Tilman’s study showed that the world will demand 100 percent more calories in 2050 than in 2005, that is the equivalent of only a 68 percent increase over production levels in 2014, the most recent year with available data. To meet the FAO projection, which used different assumptions and projected lower demand, production would have to increase only 26 percent from 2014 levels.

“Given how much production has increased recently, it is pretty misleading to continue to argue that we need to double our crop output by 2050,” Hunter said.

Aiming to double food production makes it much harder to move the needle on our environmental challenges.

“To double food production, we would have to increase global agricultural output faster than we ever have before, and we are at a point in the developed world where we already are pushing our farming systems to the max. We don’t know how to double yields in these systems, especially without multiplying our environmental impacts,” Hunter said.

Despite increased discussion of sustainability in agriculture, the common narrative that we need to drastically increase food production is seldom challenged in agricultural circles, according to the researchers. This is partly because definitions of sustainability vary widely, ranging from “not increasing agriculture’s environmental footprint” to achieving “major reductions in environmental impact.”

The researchers present hard data and quantitative goals to help clear up this confusion. For global greenhouse gas emissions and nutrient pollution in the Mississippi River Basin, the data show that agriculture’s environmental performance is going in the wrong direction, with aggregate impacts steadily increasing. Science-based goals indicate that these impacts must fall sharply over the coming decades to avoid the worst impacts of climate change and reduce the size of the “dead zone” in the Gulf of Mexico.

The authors argue for research and policy efforts to help identify production methods that can meet growing global food demand while also hitting sustainability targets.

“Even with lower demand projections, growing enough food while protecting the environment will be a daunting challenge,” Hunter said. “We call on researchers, policymakers and farmers to embrace this recalibrated vision of the future of agriculture and start working toward these goals.”

Source:Science Daily

{The amount of effort required to do something influences what we think we see, finds a new UCL study suggesting we’re biased towards perceiving anything challenging to be less appealing.}

“Our brain tricks us into believing the low-hanging fruit really is the ripest,” says Dr Nobuhiro Hagura, who led the UCL team before moving to NICT in Japan. “We found that not only does the cost to act influence people’s behaviour, but it even changes what we think we see.”

For the study, published in eLife, a total of 52 participants took part in a series of tests where they had to judge whether a cloud of dots on a screen was moving to the left or to the right. They expressed their decisions by moving a handle held in the left or right hand respectively. When the researchers gradually added a load to one of the handles, making it more difficult to move, the volunteers’ judgements about what they saw became biased, and they started to avoid the effortful response. If weight was added to the left handle, participants were more likely to judge the dots to be moving rightwards as that decision was slightly easier for them to express. Crucially, the participants did not become aware of the increasing load on the handle: their motor system automatically adapted, triggering a change in their perception.

“The tendency to avoid the effortful decision remained even when we asked people to switch to expressing their decision verbally, instead of pushing on the handles,” Dr Hagura said. “The gradual change in the effort of responding caused a change in how the brain interpreted the visual input. Importantly, this change happened automatically, without any awareness or deliberate strategy.”

“Traditionally, scientists have assumed the visual system gives us perceptual information, and the motor system is a mere downstream output channel, which expresses our decision based on what we saw, without actually influencing the decision itself. Our experiments suggest an alternative view: the motor response that we use to report our decisions can actually influence the decision about what we have seen,” he said.

The researchers believe that our daily decisions could be modified not just through deliberate cognitive strategies, but also by designing the environment to make these decisions slightly more effortful. “The idea of ‘implicit nudge’ is currently popular with governments and advertisers,” said co-author Professor Patrick Haggard (UCL Institute of Cognitive Neuroscience). “Our results suggest these methods could go beyond changing how people behave, and actually change the way the world looks. Most behaviour change focuses on promoting a desired behaviour, but our results suggest you could also make it less likely that people see the world a certain way, by making a behaviour more or less effortful. Perhaps the parent who places the jar of biscuits on a high shelf actually makes them look less tasty to the toddler playing on the floor.”

Source:Science Daily

{Empathy and emotional awareness do not affect our moral decisions. This is suggested by a new study published on Social Neuroscience and led by SISSA neuroscientist Marilena Aiello. Our choices do not depend on our empathy. The difference, instead, lies in our emotional reactions, more pronounced in more empathic people. In particular if we opt for uncomfortable decisions for a greater good.}

Could you harm another person to save yourself? Could you kill one person to save five? The answer depends neither on our ability to share someone else’s feelings — known as empathy — nor on our lack of emotional awareness — known as alexithymia. Surprisingly, the decision taken will be the same, both for emotional and detached people. The difference lies instead in the emotional reactions to the decision-making process.

“This is the first study to analyse at the same time the role of empathy and alexithymia in moral choices through decision-making rather than judgment tasks, in order to investigate what happens when subjects are directly involved” Marilena Aiello and Cinzia Cecchetto, first author of the study, explain. “Moreover, for the first time we examined the emotional reactions with both explicit and implicit measures, combining participants’ self-reports with two physiological indices: heart rate and skin conductance.”

The study involved forty-one volunteers, whose levels of empathy and alexithymia were assessed through standard questionnaires used by clinicians. Participants had to solve forty-six dilemmas, with either deontological — i.e. based on the principle of not harming others — or utilitarian choices — i.e. based on the achievement of a greater good. During the tasks, researchers monitored heart rate and skin conductance of participants, who, at the end of each dilemma, reported on their emotional state.

To better understand, let’s imagine there is a runaway trolley barrelling down the railway tracks. Ahead, on the tracks, there are five people. The only way to save them is by pulling a lever that will make the trolley switch to a side track, where, however, there is another person. Would you pull the lever, diverting the trolley onto the side track to save five people? The utilitarian choice would be “yes,” the deontological one “no.”

“We expected a high number of deontological choices in individuals with high empathy and a high number of utilitarian choices in people with high alexithymia. Instead we found out that the type of decision depends neither on our empathy nor on our alexithymia” Cinzia Cecchetto comments. “However, both explicit and implicit measures of emotional reactions confirmed what we expected: more emphatic individuals experience higher distress in utilitarian choices. Similar results appeared only through implicit measures in individuals with high levels of alexithymia who, in line with the type of disorder, showed reduced physiological activation during moral decisions, but normal self-report ratings..”

“These are important results, not only because they suggest that moral decisions are more rational than what was previously suggested, but also for the methodological approach” Marilena Aiello concludes.

Source:Science Daily

{These desert ants live in salt pans and are ideal models for navigation research. When they set out in search of food in their flat, bare, hostile environment, they are nevertheless always able to find their way back to their nest on the shortest route possible. They have an internal navigation system. }

The ants measure the distance they have gone by recording how many steps they have taken — and they use the sun for directional orientation, taking into account its movement over time via their own internal clock. A team of researchers led by Dr. Matthias Wittlinger of the University of Freiburg developed a tiny treadmill, on which the ants behave just as they do in the wild. “This gives us almost unlimited possibilities to test the mechanisms and neural basis of our model animal’s spatial orientation and navigation — in the laboratory,” says Wittlinger. “We can place the ants in a virtual world and incorporate certain changes into it to see how they react.” The the experiments are expected to yield information which will be useful in the development of autonomous robots as well as in other areas. The team of biologists published their results in the Journal of Experimental Biology.

The ant treadmill is like a ball on top of which the insect can walk around, a bit like a hamster in a wheel. To the ant, it is like walking in its normal environment — although it doesn’t really go anywhere. The team developed the spherical treadmill in such a way that it enables the ant to walk using a natural gait, even when moving and changing direction quickly. The spherical treadmill contains optical sensors — like those in a computer mouse — which record precisely the ant’s direction and speed.

In the experiments the ant initially travels some ten meters from its nest — whether in the field or in the laboratory — storing information about the path it has taken. Then the researchers place it into the treadmill. The ant then moves exactly as it would if it were returning to its nest. It first heads back to the nest as directly as possible. Once it has arrived in the general area of the nest, the ant switches to search mode, taking a meandering path so as to find the exact location. The biologists have observed that the ants adapt their speed to the relevant phase of their journey — fast on the initial homeward trip, then slow in the searching phase. Comparisons between the virtual journey inside the treadmill and the necessary trip on the ground show that the insects have a high-precision navigation system.

Source:Science Daily

{New research finds that dopamine is involved in human bonding.}

In new research published Monday in the journal Proceedings of the National Academy of Sciences, Northeastern University psychology professor Lisa Feldman Barrett found, for the first time, that the neurotransmitter dopamine is involved in human bonding, bringing the brain’s reward system into our understanding of how we form human attachments. The results, based on a study with 19 mother-infant pairs, have important implications for therapies addressing postpartum depression as well as disorders of the dopamine system such as Parkinson’s disease, addiction, and social dysfunction.

“The infant brain is very different from the mature adult brain — it is not fully formed,” says Barrett, University Distinguished Professor of Psychology and author of the forthcoming book How Emotions Are Made: The Secret Life of the Brain. “Infants are completely dependent on their caregivers. Whether they get enough to eat, the right kind of nutrients, whether they’re kept warm or cool enough, whether they’re hugged enough and get enough social attention, all these things are important to normal brain development. Our study shows clearly that a biological process in one person’s brain, the mother’s, is linked to behavior that gives the child the social input that will help wire his or her brain normally. That means parents’ ability to keep their infants cared for leads to optimal brain development, which over the years results in better adult health and greater productivity.”

To conduct the study, the researchers turned to a novel technology: a machine capable of performing two types of brain scans simultaneously — functional magnetic resonance imaging, or fMRI, and positron emission tomography, or PET.

fMRI looks at the brain in slices, front to back, like a loaf of bread, and tracks blood flow to its various parts. It is especially useful in revealing which neurons are firing frequently as well as how different brain regions connect in networks. PET uses a small amount of radioactive chemical plus dye (called a tracer) injected into the bloodstream along with a camera and a computer to produce multidimensional images to show the distribution of a specific neurotransmitter, such as dopamine or opioids.

Barrett’s team focused on the neurotransmitter dopamine, a chemical that acts in various brain systems to spark the motivation necessary to work for a reward. They tied the mothers’ level of dopamine to her degree of synchrony with her infant as well as to the strength of the connection within a brain network called the medial amygdala network that, within the social realm, supports social affiliation.

“We found that social affiliation is a potent stimulator of dopamine,” says Barrett. “This link implies that strong social relationships have the potential to improve your outcome if you have a disease, such as depression, where dopamine is compromised. We already know that people deal with illness better when they have a strong social network. What our study suggests is that caring for others, not just receiving caring, may have the ability to increase your dopamine levels.”

Before performing the scans, the researchers videotaped the mothers at home interacting with their babies and applied measurements to the behaviors of both to ascertain their degree of synchrony. They also videotaped the infants playing on their own.

Once in the brain scanner, each mother viewed footage of her own baby at solitary play as well as an unfamiliar baby at play while the researchers measured dopamine levels, with PET, and tracked the strength of the medial amygdala network, with fMRI.

The mothers who were more synchronous with their own infants showed both an increased dopamine response when viewing their child at play and stronger connectivity within the medial amygdala network. “Animal studies have shown the role of dopamine in bonding but this was the first scientific evidence that it is involved in human bonding,” says Barrett. “That suggests that other animal research in this area could be directly applied to humans as well.”

The findings, says Barrett, are “cautionary.” “They have the potential to reveal how the social environment impacts the developing brain,” she says. “People’s future health, mental and physical, is affected by the kind of care they receive when they are babies. If we want to invest wisely in the health of our country, we should concentrate on infants and children, eradicating the adverse conditions that interfere with brain development.”

Source:Science Daily

{Patients who complain they can’t hear their friends at a noisy restaurant, but pass a hearing test in their doctor’s office, may be describing hidden hearing loss.}

Now, less than six years since its initial description, scientists have made great strides in understanding what hidden hearing loss is and what causes it. In research published in Nature Communications, University of Michigan researchers report a new unexpected cause for this auditory neuropathy, a step toward the eventual work to identify treatments.

“If people can have hidden hearing loss for different reasons, having the ability to make the right diagnosis of the pathogenesis will be critical,” says author Gabriel Corfas, Ph.D., director of the Kresge Hearing Research Institute at Michigan Medicine’s Department of Otolaryngology — Head and Neck Surgery.

Corfas published the research with co-author Guoqiang Wan, now with Nanjing University in China. They discovered using mice that disruption in the Schwann cells that make myelin, which insulates the neuronal axons in the ear, leads to hidden hearing loss. This means hidden hearing loss could be behind auditory deficits seen in acute demyelinating disorders such as Guillain-Barré syndrome, which can be caused by Zika virus.

Corfas and Wan used genetic tools to induce loss of myelin in the auditory nerve of mice, modeling Guillain-Barré. Although the myelin regenerated in a few weeks, the mice developed a permanent hidden hearing loss. Even after the myelin regenerated, damage to a nerve structure called the heminode remained.

Synapse loss versus myelin disruption

When the ear is exposed to loud noises over time, synapses connecting hair cells with the neurons in the inner ear are lost. This loss of synapses has previously been shown as a mechanism leading to hidden hearing loss.

In an audiologist’s quiet testing room, only a few synapses are needed to pick up sounds. But in a noisy environment, the ear must activate specific synapses. If they aren’t all there, it’s difficult for people to make sense of the noise or words around them. That is hidden hearing loss, Corfas says.

“Exposure to noise is increasing in our society, and children are exposing themselves to high levels of noise very early in life,” Corfas says. “It’s clear that being exposed to high levels of sound might contribute to increases in hidden hearing loss.”

The newly identified cause — deficiency in Schwann cells — could occur in individuals who have already had noise exposure-driven hidden hearing loss as well. “Both forms of hidden hearing loss, noise exposure and loss of myelin, can occur in the same individual for an additive effect,” Corfas says.

Previously, Corfas’ group succeeded in regenerating synapses in mice with hidden hearing loss, providing a path to explore for potential treatment.

While continuing this work, Corfas started to investigate other cells in the ear, which led to uncovering the new mechanism.

There are no current treatments for hidden hearing loss. But as understanding of the condition improves, the goal is for the research to lead to the development of drugs to treat it.

“Our findings should influence the way hidden hearing loss is diagnosed and drive the future of clinical trials searching for a treatment,” Corfas says. “The first step is to know whether a person’s hidden hearing loss is due to synapse loss or myelin/heminode damage.”

Source:Science Daily

{Study looks at neural mechanisms of paternal caregiving.}

Fathers given boosts of the hormone oxytocin show increased activity in brain regions associated with reward and empathy when viewing photos of their toddlers, an Emory University study finds.

“Our findings add to the evidence that fathers, and not just mothers, undergo hormonal changes that are likely to facilitate increased empathy and motivation to care for their children,” says lead author James Rilling, an Emory anthropologist and director of the Laboratory for Darwinian Neuroscience. “They also suggest that oxytocin, known to play a role in social bonding, might someday be used to normalize deficits in paternal motivation, such as in men suffering from post-partum depression.”

The journal Hormones and Behavior published the results of the study, the first to look at the influence of both oxytocin and vasopressin — another hormone linked to social bonding — on brain function in human fathers.

A growing body of literature shows that paternal involvement plays a role in reducing child mortality and morbidity, and improving social, psychological and educational outcomes. But not every father takes a “hands-on” approach to caring for his children.

“I’m interested in understanding why some fathers are more involved in caregiving than others,” Rilling says. “In order to fully understand variation in caregiving behavior, we need a clear picture of the neurobiology and neural mechanisms that support the behavior.”

Researchers have long known that when women go through pregnancy they experience dramatic hormonal changes that prepare them for child rearing. Oxytocin, in particular, was traditionally considered a maternal hormone since it is released into the bloodstream during labor and nursing and facilitates the processes of birth, bonding with the baby and milk production.

More recently, however, it became clear that men can also undergo hormonal changes when they become fathers, including increases in oxytocin. Evidence shows that, in fathers, oxytocin facilitates physical stimulation of infants during play as well as the ability to synchronize their emotions with their children.

In order to investigate the neural mechanisms involved in oxytocin and paternal behavior, the Rilling lab used functional Magnetic Resonance Imaging (fMRI) to compare neural activity in men with and without doses of oxytocin, administered through a nasal spray. The participants in the experiment were all healthy fathers of toddlers, between the ages of one and two. While undergoing fMRI brain scans, each participant was shown a photo of his child, a photo of a child he did not know and a photo of an adult he did not know.

When viewing an image of their offspring, participants dosed with oxytocin showed significantly increased neural activity in brain systems associated with reward and empathy, compared to placebo. This heightened activity (in the caudate nucleus, dorsal anterior cingulate and visual cortex) suggests that doses of oxytocin may augment feelings of reward and empathy in fathers, as well as their motivation to pay attention to their children.

Surprisingly, the study results did not show a significant effect of vasopressin on the neural activity of fathers, contrary to the findings of some previous studies on animals.

Research in prairie voles, which bond for life, for instance, has shown that vasopressin promotes both pair-bonding and paternal caregiving.

“It could be that evolution has arrived at different strategies for motiving paternal caregiving in different species,” Rilling says.

Source:Science Daily