Empathy Varies by Age and Gender: Women in Their 50s Are Tops

Jan. 30, 2013 — According to a new study of more than 75,000 adults, women in that age group are more empathic than men of the same age and than younger or older people.


“Overall, late middle-aged adults were higher in both of the aspects of empathy that we measured,” says Sara Konrath, co-author of an article on age and empathy forthcoming in the Journals of Gerontology: Psychological and Social Sciences.

“They reported that they were more likely to react emotionally to the experiences of others, and they were also more likely to try to understand how things looked from the perspective of others.”

For the study, researchers Ed O’Brien, Konrath and Linda Hagen at the University of Michigan and Daniel Grühn at North Carolina State University analyzed data on empathy from three separate large samples of American adults, two of which were taken from the nationally representative General Social Survey.

They found consistent evidence of an inverted U-shaped pattern of empathy across the adult life span, with younger and older adults reporting less empathy and middle-aged adults reporting more.

According to O’Brien, this pattern may result because increasing levels of cognitive abilities and experience improve emotional functioning during the first part of the adult life span, while cognitive declines diminish emotional functioning in the second half.

But more research is needed in order to understand whether this pattern is really the result of an individual’s age, or whether it is a generational effect reflecting the socialization of adults who are now in late middle age.

“Americans born in the 1950s and ’60s — the middle-aged people in our samples — were raised during historic social movements, from civil rights to various antiwar countercultures,” the authors explain. “It may be that today’s middle-aged adults report higher empathy than other cohorts because they grew up during periods of important societal changes that emphasized the feelings and perspectives of other groups.”

Earlier research by O’Brien, Konrath and colleagues found declines in empathy and higher levels of narcissism among young people today as compared to earlier generations of young adults.

O’Brien and Konrath plan to conduct additional research on empathy, to explore whether people can be trained to show more empathy using new electronic media, for example. “Given the fundamental role of empathy in everyday social life and its relationship to many important social activities such as volunteering and donating to charities, it’s important to learn as much as we can about what factors increase and decrease empathic responding,” says Konrath.


Story Source:

The above story is reprinted from materials provided byUniversity of Michigan. The original article was written by Diane Swanbrow.

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


Journal Reference:

  1. E. O’Brien, S. H. Konrath, D. Gruhn, A. L. Hagen.Empathic Concern and Perspective Taking: Linear and Quadratic Effects of Age Across the Adult Life Span.The Journals of Gerontology Series B: Psychological Sciences and Social Sciences, 2012; DOI:10.1093/geronb/gbs055
University of Michigan (2013, January 30). Empathy varies by age and gender: Women in their 50s are tops. ScienceDaily. Retrieved January 31, 2013, from http://www.sciencedaily.com/releases/2013/01/130130184324.htm
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Bonobos Predisposed to Show Sensitivity to Others

Jan. 30, 2013 — Comforting a friend or relative in distress may be a more hard-wired behavior than previously thought, according to a new study of bonobos, which are great apes known for their empathy and close relation to humans and chimpanzees. This finding provides key evolutionary insight into how critical social skills may develop in humans.


The results are published in the online journal PLOS ONE.

Researchers from the Yerkes National Primate Research Center, Emory University, observed juvenile bonobos at the Lola ya Bonobo sanctuary in the Democratic Republic of Congo engaging in consolation behavior more than their adult counterparts. Juvenile bonobos (ages 3 to 7) are equivalent to preschool or elementary school-aged children.

Zanna Clay, PhD, a postdoctoral fellow in Emory’s Department of Psychology, and Frans de Waal, PhD, director of the Living Links Center at Yerkes and C.H. Candler Professor of Psychology at Emory, led the study.

“Our findings suggest that for bonobos, sensitivity to the emotions of others emerges early and does not require advanced thought processes that develop only in adults,” Clay says.

Starting at around age two, human children usually display consolation behavior, a sign of sensitivity to the emotions of others and the ability to take the perspective of another. Consolation has been observed in humans, bonobos, chimpanzees and other animals, including dogs, elephants and some types of birds, but has not been seen in monkeys.

At the Lola ya Bonobo sanctuary, most bonobos come as juvenile or infant orphans because their parents are killed for meat or captured as pets. A minority of bonobos in the sanctuary is second generation and raised by their biological mothers. The researchers found bonobos raised by their own mothers were more likely to comfort others compared to orphaned bonobos. This may indicate early life stress interferes with development of consolation behavior, while a stable parental relationship encourages it, Clay says.

Clay observed more than 350 conflicts between bonobos at the sanctuary during several months. Some conflicts involved violence, such as hitting, pushing or grabbing, while others only involved threats or chasing. Consolation occurred when a third bonobo — usually one that was close to the scene of conflict — comforted one of the parties in the conflict.

Consolation behavior includes hugs, grooming and sometimes sexual behavior. Consolation appears to lower stress in the recipient, based on a reduction in the recipient’s rates of self-scratching and self-grooming, the authors write.

“We found strong effects of friendship and kinship, with bonobos being more likely to comfort those they are emotionally close to,” Clay says. “This is consistent with the idea that empathy and emotional sensitivity contribute to consolation behavior.”

In future research, Clay plans to take a closer look at the emergence of consolation behavior in bonobos at early ages. A process that may facilitate development of consolation behavior is when older bonobos use younger ones as teddy bears; their passive participation may get the younger bonobos used to the idea, she says.

 

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The above story is reprinted from materials provided byEmory University, via EurekAlert!, a service of AAAS.

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


Journal Reference:

  1. Zanna Clay, Frans B. M. de Waal. Bonobos Respond to Distress in Others: Consolation across the Age SpectrumPLoS ONE, 2013; 8 (1): e55206 DOI:10.1371/journal.pone.0055206
Emory University (2013, January 30). Bonobos predisposed to show sensitivity to others.ScienceDaily. Retrieved January 31, 2013, from http://www.sciencedaily.com/releases/2013/01/130130184316.htm

Chimp See, Chimp Learn: First Evidence for Chimps Improving Tool Use Techniques by Watching Others

Jan. 30, 2013 — Chimps can learn more efficient ways to use a tool by watching what others do, according to research published Jan. 30 in the open access journalPLOS ONE by Shinya Yamamoto and colleagues from Kyoto University and Kent University, UK. Their study presents the first experimental evidence that chimps, like humans, can watch and learn a group member’s invention of a better technique.

This image is of the “dipping” technique performed by chimpanzee Ayumu. He uses his mouth to insert the tube into the bottle. In form, his technique is identical to the “straw-sucking” technique. However, instead of leaving the tube in and retrieving the juice via sucking, he removes the tube and licks the tip. (Credit: Credit: Citation: Yamamoto S, Humle T, Tanaka M (2013) Basis for Cumulative Cultural Evolution in Chimpanzees: Social Learning of a More Efficient Tool-Use Technique. PLOS ONE 8(1): e55768. doi:10.1371/journal.pone.0055768)

 

Chimps in the study were provided juice-boxes with a small hole and straws to drink with. One group of chimps used the straws like dipsticks, dipping and removing them to suck on the end, while the other group learned to suck through the straw directly. Learning both techniques required the same cognitive and motor skills, but chimps that drank through the straw got considerably more juice in a shorter amount of time. When the first group of chimps watched either a human or a chimp demonstrate the more efficient ‘straw-sucking’ technique, all of them switched to using this instead.

The study concludes, “When chimpanzees are dissatisfied with their own technique, they may socially learn an improved technique by closely observing a proficient demonstrator.”

According to the authors, their results provide insights into the cognitive basis for the evolution of culture in chimpanzees, and suggest ways that culture could evolve in non-human animals.

The present study was financially supported by grants-in-aid from the Ministry of Education, Culture, Sports, Science and Technology in Japan (MEXT: 20002001, 24000001, and MEXT special grant ”Human Evolution” to T. Matsuzawa) and from Japan Society for the promotion of Science (JSPS: 18-3451, 21-9340, 22800034 and 40585767 to S. Yamamoto).


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Journal Reference:

  1. Shinya Yamamoto, Tatyana Humle, Masayuki Tanaka.Basis for Cumulative Cultural Evolution in Chimpanzees: Social Learning of a More Efficient Tool-Use TechniquePLoS ONE, 2013; 8 (1): e55768 DOI:10.1371/journal.pone.0055768
Public Library of Science (2013, January 30). Chimp see, chimp learn: First evidence for chimps improving tool use techniques by watching others. ScienceDaily. Retrieved January 31, 2013, from http://www.sciencedaily.com/releases/2013/01/130130184158.htm

Leading by the Nose: Star-Nosed Mole Reveals How Mammals Perceive Touch, Pain

Jan. 30, 2013 — The most sensitive patch of mammalian skin known to us isn’t human but on the star-shaped tip of the star-nosed mole’s snout. Researchers studying this organ have found that the star has a higher proportion of touch-sensitive nerve endings than pain receptors, according to a study published Jan. 30 in the open access journalPLOS ONE by Diana Bautista and colleagues from the University of California, Berkeley and Vanderbilt University.


 

Touch and pain are closely intertwined sensations, but very little is known about how these sensations are detected in our cells. In this study, the authors turned to a unique species for answers: the star-nosed mole. In addition to its distinction as the fastest-eating mammal known, the star-nosed mole also possesses one of the most sensitive tactile organs known in the animal kingdom. The star on its nose has the highest density of nerve endings known in any mammalian skin, with over 100,000 fibers in a patch of skin about 1 cm. in diameter. The authors found these nerve endings significantly enriched in neurons sensitive to light touch, with a lower proportion of neurons that detect and respond to pain.

The novel touch and pain receptors they identified in the star-nosed mole were also detected in sensory receptors in mice and humans, suggesting that these receptors are likely to be more common across other mammals as well. According to the authors, their results highlight how examining diverse and highly specialized species can reveal fundamental aspects of biology common across different animals.

Lead author on the study Bautista says, “By studying the star-nosed mole we identified candidate genes that may mediate touch and pain. These genes represent new potential targets for the development of much needed drugs and therapies to treat chronic pain.”

The authors are supported by a U.S. National Institutes of Health Innovator Award DOD007123A, the Pew Scholars Program, and the McKnight Scholars Fund (to DMB) and NSF grant 0844743 (to KCC).

 

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The above story is reprinted from materials provided byPublic Library of Science.

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Journal Reference:

  1. Kristin A. Gerhold, Maurizio Pellegrino, Makoto Tsunozaki, Takeshi Morita, Duncan B. Leitch, Pamela R. Tsuruda, Rachel B. Brem, Kenneth C. Catania, Diana M. Bautista.The Star-Nosed Mole Reveals Clues to the Molecular Basis of Mammalian TouchPLoS ONE, 2013; 8 (1): e55001 DOI: 10.1371/journal.pone.0055001
Public Library of Science (2013, January 30). Leading by the nose: Star-nosed mole reveals how mammals perceive touch, pain.ScienceDaily. Retrieved January 31, 2013, from http://www.sciencedaily.com/releases/2013/01/130130184156.htm

Sorting out Stroking Sensations: Biologists Find Individual Neurons in Skin That React to Massage

Jan. 30, 2013 — The skin is a human being’s largest sensory organ, helping to distinguish between a pleasant contact, like a caress, and a negative sensation, like a pinch or a burn. Previous studies have shown that these sensations are carried to the brain by different types of sensory neurons that have nerve endings in the skin. Only a few of those neuron types have been identified, however, and most of those detect painful stimuli. Now biologists at the California Institute of Technology (Caltech) have identified in mice a specific class of skin sensory neurons that reacts to an apparently pleasurable stimulus.

Left: An image of fluorescent nerve fibers in the spinal cord, viewed through the microscope prior to stimulation. Right: A magnified view showing the increase in fluorescence signal in one specific fiber (boxed area, red color) during stroking with the brush. (Credit: Anderson Lab / Caltech)

More specifically, the team, led by David J. Anderson, Seymour Benzer Professor of Biology at Caltech, was able to pinpoint individual neurons that were activated by massage-like stroking of the skin. The team’s results are outlined in the January 31 issue of the journal Nature.

“We’ve known a lot about the neurons that detect things that make us hurt or feel pain, but we’ve known much less about the identity of the neurons that make us feel good when they are stimulated,” says Anderson, who is also an investigator with the Howard Hughes Medical Institute. “Generally it’s a lot easier to study things that are painful because animals have evolved to become much more sensitive to things that hurt or are fearful than to things that feel good. Showing a positive influence of something on an animal model is not that easy.”

In fact, the researchers had to develop new methods and technologies to get their results. First, Sophia Vrontou, a postdoctoral fellow in Anderson’s lab and the lead author of the study, developed a line of genetically modified mice that had tags, or molecular markers, on the neurons that the team wanted to study. Then she placed a molecule in this specific population of neurons that fluoresced, or lit up, when the neurons were activated.

“The next step was to figure out a way of recording those flashes of light in those neurons in an intact mouse while stroking and poking its body,” says Anderson. “We took advantage of the fact that these sensory neurons are bipolar in the sense that they send one branch into the skin that detects stimuli, and another branch into the spinal cord to relay the message detected in the skin to the brain.”

The team obtained the needed data by placing the mouse under a special microscope with very high magnification and recording the level of fluorescent light in the fibers of neurons in the spinal cord as the animal was stroked, poked, tickled, and pinched. Through a painstaking process of applying stimuli to one tiny area of the animal’s body at a time, they were able to confirm that certain neurons lit up only when stroked. A different class of neurons, by contrast, was activated by poking or pinching the skin, but not by stroking.

“Massage-like stroking is a stimulus that, if were we to experience it, would feel good to us, but as scientists we can’t just assume that because something feels good to us, it has to also feel good to an animal,” says Anderson. “So we then had to design an experiment to show that artificially activating just these neurons — without actually stroking the mouse — felt good to the mouse.”

The researchers did this by creating a box that contained left, right, and center rooms connected by little doors. The left and right rooms were different enough that a mouse could distinguish them through smell, sight, and touch. In the left room, the mouse received an injection of a drug that selectively activated the neurons shown to detect massage-like stroking. In the room on the right, the mouse received a control injection of saline. After a few sessions in each outer room, the animal was placed in the center, with the doors open to see which room it preferred. It clearly favored the room where the massage-sensitive neurons were activated. According to Anderson, this was the first time anyone has used this type of conditioned place-preference experiment to show that activating a specific population of neurons in the skin can actually make an animal experience a pleasurable or rewarding state — in effect, to “feel good.”

The team’s findings are significant for several reasons, he says. First, the methods that they developed give scientists who have discovered a new kind of neuron a way to find out what activates that neuron in the skin.

“Since there are probably dozens of different kinds of neurons that innervate the skin, we hope this will advance the field by making it possible to figure out all of the different kinds of neurons that detect various types of stimuli,” explains Anderson. The second reason the results are important, he says, “is that now that we know these neurons detect massage-like stimuli, the results raise new sets of questions about which molecules in those neurons help the animal detect stroking but not poking.”

The other benefit of their new methods, Anderson says, is that they will allow researchers to, in principle, trace the circuitry from those neurons up into the brain to ask why and how activating these neurons makes the animal feel good, whereas activating other neurons that are literally right next to them in the skin makes the animal feel bad.

“We are now most interested in how these neurons communicate to the brain through circuits,” says Anderson. “In other words, what part of the circuit in the brain is responsible for the good feeling that is apparently produced by activating these neurons? It may seem frivolous to be identifying massage neurons in a mouse, but it could be that some good might come out of this down the road.”

Allan M. Wong, a senior research fellow in biology at Caltech, and Kristofer K. Rau and Richard Koerber from the University of Pittsburgh were also coauthors on the Nature paper, “Genetic identification of C fibers that detect massage-like stroking of hairy skin in vivo.” Funding for this research was provided by the National Institutes of Health, the Human Frontiers Science Program, and the Helen Hay Whitney Foundation.


Story Source:

The above story is reprinted from materials provided byCalifornia Institute of Technology. The original article was written by Katie Neith.

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


Journal Reference:

  1. Sophia Vrontou, Allan M. Wong, Kristofer K. Rau, H. Richard Koerber, David J. Anderson. Genetic identification of C fibres that detect massage-like stroking of hairy skin in vivoNature, 2013; 493 (7434): 669 DOI: 10.1038/nature11810
California Institute of Technology (2013, January 30). Sorting out stroking sensations: Biologists find individual neurons in skin that react to massage. ScienceDaily. Retrieved January 31, 2013, from http://www.sciencedaily.com/releases/2013/01/130130152908.htm

Mindfulness Meditation Heightens a Listener’s Musical Engagement

Jan. 30, 2013 — When De’Anthony Thomas returned the opening kickoff for a touchdown in the 2013 Fiesta Bowl, says University of Oregon researcher Frank Diaz, Thomas put Ducks fans into a heightened zone of engagement for watching the game, not unlike what was experienced by music students who were first exposed to a brief session of mindfulness meditation before hearing an opera passage.


As a high school orchestra and band educator in Florida, Diaz had flirted with yoga and light meditation in a quest to heighten music engagement. He noticed, anecdotally, a connection to improved attention by his students. Now a professor in the UO School of Music and Dance, Diaz is exploring how mindfulness meditation may enhance both music engagement and performance. He began the research while a doctoral student at Florida State University.

In a study appearing online ahead of publication in the journalPsychology of Music, he reports a rise of focused engagement for student participants who listened to a 10-minute excerpt of Giacomo Puccini’s opera “La Boheme” after listening to a 15-minute recording of a segment produced by the Duke University Center for Mindfulness Research. Mindfulness is an ancient technique that helps direct a person’s consciousness into the present. In this case, listeners were reminded to focus on physical sensations or their breathing if their attention drifted.

The 132 student participants were divided into four groups. Those undergoing mindfulness preparation were then additionally divided into subgroups that were tested for two types of peak experiences, a highly emotional experience known as aesthetic response, and flow — the listeners’ effortless engagement or how much “in the zone” they were as they listened to the music.

Control groups, which did not hear the mindfulness recording, were tested either for aesthetic or flow responses. Subjects were tested for real time responses using a Continuous Response Digital Interface developed in the late 1980s at Florida State University. The device allows subjects to turn a dial, rather than speaking, in response to how music moves them as they listen. The dial’s movement was recorded.

Overall, 97 percent of the participants had either one or several moments of flow or aesthetic response. Of the 69 subjects who engaged in mindfulness, 64 percent thought the technique had enhanced their listening experience.

There was a discrepancy between the subjects’ responses gathered in real time and summative data — how they reacted by turning the dial while listening vs. how they recalled their experience at the end of the experiments. Diaz said that the real time responses more accurately captured the attention being devoted to the music, and that the mindfulness technique helped drive participants into the zone of readiness to listen to music they’ve heard many times before.

“It tends to take habituated responses and renews them. It’s almost like a reset button,” Diaz said. “For musicians, if you’re a symphony player, you’ve probably played ‘Beethoven’s No. 9′ 10,000 times. Your response is so habituated that you don’t get any pleasure out of it anymore. The cool thing about La Boheme is that it has been used in music-related studies for years, and we have these patterns documented over time by people studying responses to music. That lets you compare past and present with a new group.”

The study, he said, has potential ramifications for music education. “Attention can be modified,” he said. “It doesn’t have to be done chemically or by changing the environment. Human beings have the capacity to learn to self-regulate their attention, and when you do that it increases the quality of typical, everyday experiences. Listening to music mindfully can be a powerful way of increasing your quality of life. We really found significant increases in the participants’ aesthetic and flow experience. Some were intense. They were really in the zone.”

The paper by Diaz is among a growing number of research projects devoted to understanding how meditative techniques such as mindfulness affect the brain and improves health and behavior.

In the current issue of SCAN (Social Cognitive and Affective Neuroscience), UO psychologist Michael Posner and Yi-Yuan Tang of Texas Tech University noted in an editorial that the numbers of research papers published on mindfulness have grown from 28 in 2001 to 397 in 2011.

Posner and Tang have collaborated on a series of projects that look at brain changes involved in a mindfulness technique called integrative body-mind training that is practiced in parts of China. Tang, who had served as a visiting professor at the UO, remains affiliated with the UO psychology department as a research professor. The pair’s editorial provides an overview of research findings in recent years and how mindfulness may apply in the mental health and medical fields.

Also in SCAN, a four-member research team that includes UO psychologist Elliot T. Berkman studied mindfulness meditation using functional magnetic resonance imaging. In a study of 31 participants, Berkman showed that the focused-breathing aspect of mindfulness meditation activated an attention network that includes the brain’s parietal and prefrontal structures.

“This research is contributing to our overall understanding of how the brain works,” said Kimberly Andrews Espy, UO vice president for research and innovation, and dean of the graduate school. “Examining these alternative means of enhancing brain activity has the potential to benefit society in a number of ways, and may lead to new treatments for mental illness, brain injuries and other disorders.”

 

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

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University of Oregon (2013, January 30). Mindfulness meditation heightens a listener’s musical engagement. ScienceDaily. Retrieved January 31, 2013, from http://www.sciencedaily.com/releases/2013/01/130130132415.htm

Scientists Learn More About How Inhibitory Brain Cells Get Excited

Jan. 30, 2013 — Scientists have found an early step in how the brain’s inhibitory cells get excited. A natural balance of excitement and inhibition keeps the brain from firing electrical impulses randomly and excessively, resulting in problems such as schizophrenia and seizures. However excitement is required to put on the brakes.


“When the inhibitory neuron is excited, its job is to suppress whatever activity it touches,” said Dr. Lin Mei, Director of the Institute of Molecular Medicine and Genetics at the Medical College of Georgia at Georgia Regents University and corresponding author of the study inNature Neuroscience.

Mei and his colleagues found that the protein erbin, crucial to brain development, is critical to the excitement.

It was known that a protein on the cell surface called TARP gamma-2, also known as stargazing, interacts with a brain cell receptor called AMPA, ensuring the receptor finds the cells surface. It is here that the receptor can be activated by the neurotransmitter glutamate. AMPA receptor activation is essential to activation of the NMDA receptor, which enables cells to communicate, ultimately enabling learning and memory, Mei said. How TARP gamma-2 was controlled, was an unknown.

Inside the nucleus of inhibitory cells in areas of the brain that control learning and memory, the researchers found erbin interacts with TARP gamma-2, enabling it to survive. “If you do not have this mechanism, your stargazing becomes very unstable and your AMPA receptor cannot be on the surface so this neuron is inactive,” Mei said. They also found that erbin is only in these inhibitory neurons, called interneurons. They’re already working on what they believe to be the counterpart for excitatory cells, which account for about 80 percent of brain cells.

“Interneurons basically control firing,” releasing GABA, a major inhibitory neurotransmitter, Mei said. They tone down or synchronize the activity of pyramidal cells, pyramid-shaped neurons that get both excitatory and inhibitory input then make the call on what action to take.

When scientists ablated the erbin gene in mice or kept erbin from interacting with TARP gamma-2, a protein that helps anchor the AMPA receptor on the cell surface, TARP gamma-2 couldn’t do its job. The result was less receptors on the cell surface and mice that were hyperactive with impaired learning and memory.

Cell activity hinges on receptor activity and receptors must be anchored on the cell surface to work. Ensuring AMPA receptors are strategically placed is a lifelong task since the busy receptors wear out and each brain cell has tons of them, Mei said.

He and his colleagues reported in the journal, Neuron, in 2007, two genes — neuregulin-1 and its receptor ErbB4 — that help maintain a healthy balance of excitement and inhibition by releasing GABA at the sight of inhibitory synapses, the communication paths between neurons. Years before, they showed the genes were also at excitatory synapses, where they also could quash activation. Both genes are involved in human development and implicated in schizophrenia and cancer.


Story Source:

The above story is reprinted from materials provided byGeorgia Health Sciences University. The original article was written by Toni Baker.

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


Journal Reference:

  1. Yanmei Tao, Yong-Jun Chen, Chengyong Shen, Zhengyi Luo, C Ryan Bates, Daehoon Lee, Sylvie Marchetto, Tian-Ming Gao, Jean-Paul Borg, Wen-Cheng Xiong, Lin Mei.Erbin interacts with TARP γ-2 for surface expression of AMPA receptors in cortical interneuronsNature Neuroscience, 2013; DOI: 10.1038/nn.3320
Georgia Health Sciences University (2013, January 30). Scientists learn more about how inhibitory brain cells get excited. ScienceDaily. Retrieved January 31, 2013, from http://www.sciencedaily.com/releases/2013/01/130130121641.htm

Previously Unknown Mechanism of Memory Formation Discovered

Jan. 30, 2013 — It takes a lot to make a memory. New proteins have to be synthesized, neuron structures altered. While some of these memory-building mechanisms are known, many are not. Some recent studies have indicated that a unique group of molecules called microRNAs, known to control production of proteins in cells, may play a far more important role in memory formation than previously thought.


Now, a new study by scientists on the Florida campus of The Scripps Research Institute has for the first time confirmed a critical role for microRNAs in the development of memory in the part of the brain called the amygdala, which is involved in emotional memory. The new study found that a specific microRNA — miR-182 — was deeply involved in memory formation within this brain structure.

“No one had looked at the role of microRNAs in amygdala memory,” said Courtney Miller, a TSRI assistant professor who led the study. “And it looks as though miR-182 may be promoting local protein synthesis, helping to support the synapse-specificity of memories.”

In the new study, published in theJournal of Neuroscience, the scientists measured the levels of all known microRNAs following an animal model of learning. A microarray analysis, which enables rapid genetic testing on a large scale, showed that more than half of all known microRNAs are expressed in the amygdala. Seven of those microRNAs increased and 32 decreased when learning occurred.

The study found that, of the microRNAs expressed in the brain, miR-182 had one of the lowest levels and these decreased further with learning. Despite these very low levels, its overexpression prevented the formation of memory and led to a decrease in proteins that regulate neuronal plasticity (neurons’ ability to adapt) through changes in structure.

These findings suggest that learning-induced suppression of miR-182 is a main supporting factor in the formation of long-term memory in the amagdala, as well as an underappreciated mechanism for regulating protein synthesis during memory consolidation, Miller said.

Further analysis identified miR-182 as a repressor of proteins that control actin — a major component of the cytoskeleton, the scaffolding that holds cells together.

“We know that memory formation requires changes in dendritic spines on the neurons through regulation of the actin cytoskeleton,” Miller said. “When miR-182 is suppressed through learning it halts, at least in part, repression of actin-regulating proteins, so there’s a good chance that miR-182 exerts important control over the actin cytoskeleton.”

Miller is now interested in whether or not high levels of miR-182 accumulate in the aging brain, something that would help to explain a tendency toward memory loss in the elderly. She also notes that other research has shown that animal models lacking miR-182 had no significant physical or cellular abnormalities, suggesting that miR-182 could be a viable target for drug discovery.


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The above story is reprinted from materials provided byThe Scripps Research Institute.

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Journal Reference:

  1. E. M. Griggs, E. J. Young, G. Rumbaugh, C. A. Miller.MicroRNA-182 Regulates Amygdala-Dependent Memory FormationJournal of Neuroscience, 2013; 33 (4): 1734 DOI: 10.1523/JNEUROSCI.2873-12.2013
The Scripps Research Institute (2013, January 30). Previously unknown mechanism of memory formation discovered. ScienceDaily. Retrieved January 31, 2013, from http://www.sciencedaily.com/releases/2013/01/130130121545.htm

Female Deer Take Control During Mating Season

Jan. 30, 2013 — A new study provides the first evidence of polyandry — when females choose to mate with more than one male — in female fallow deer.


 

According to a team of scientists from Queen Mary, University of London, UWE Hartpury, and University College Dublin, female fallow deer play an active role in selecting their mates, with a consistent proportion (on average 12 per cent) choosing to mate with multiple males each year.

“Until now there has been limited understanding of female mate choice during this process, with many people believing that female deer are controlled by males during the mating season, explains co-author Dr Alan McElligott from Queen Mary’s School of Biological and Chemical Sciences.

“In fact, not only do females decide with whom they mate, but our study has shown that a proportion choose to mate more than once each year, and with different males. Traditionally most research of this type has focused on male deer mating strategies and female behaviour during the rut was often overlooked.”

The research was carried out on a herd of fallow deer in Dublin’s Phoenix Park over a 10-year period.

Dr Elodie Briefer, also from Queen Mary’s School of Biological Sciences, said: “While the majority of female deer only mated once, we found that 5-20 per cent of the female fallow deer population mated with multiple males over the 10-year period. We believe that the presence of polyandrous females each year in the population is very good evidence of female fallow deer adopting different mating strategies.”

The researchers suggest that the most likely explanation for polyandry in female fallow deer is to ensure that they become pregnant. For example, they observed that the female deer were more likely to mate again if their first mate was relatively old, or he had mated many times before, potentially indicating sperm depletion.

Dr Mary Farrell from UWE Hartpury commented: “The timing of breeding is driven by the best time for offspring to be born. If a female is not fertilised during the first breeding season, she will come back into oestrous three weeks later. This causes a delay in the birth of the fawn, which can reduce its chances of survival.”

The research was published in the journal Behavioral Ecology and Sociobiology on January 30.

 

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The above story is reprinted from materials provided byQueen Mary, University of London.

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


Journal Reference:

  1. Elodie F. Briefer, Mary E. Farrell, Thomas J. Hayden, Alan G. McElligott. Fallow deer polyandry is related to fertilization insuranceBehavioral Ecology and Sociobiology, 2013; DOI: 10.1007/s00265-013-1485-x
Queen Mary, University of London (2013, January 30). Female deer take control during mating season. ScienceDaily. Retrieved January 31, 2013, from http://www.sciencedaily.com/releases/2013/01/130130111920.htm

How Brain Cells Shape Temperature Preferences

Jan. 29, 2013 — While the wooly musk ox may like it cold, fruit flies definitely do not. They like it hot, or at least warm. In fact, their preferred optimum temperature is very similar to that of humans — 76 degrees F.

Scientists have known that a type of brain cell circuit helps regulate a variety of innate and learned behavior in animals, including their temperature preferences. What has been a mystery is whether or not this behavior stems from a specific set of neurons (brain cells) or overlapping sets.

Now, a new study from The Scripps Research Institute (TSRI) shows that a complex set of overlapping neuronal circuits work in concert to drive temperature preferences in the fruit fly Drosophila by affecting a single target, a heavy bundle of neurons within the fly brain known as the mushroom body. These nerve bundles, which get their name from their bulbous shape, play critical roles in learning and memory.

The study, published in the January 30, 2013 edition of the Journal of Neuroscience, shows that dopaminergic circuits — brain cells that synthesize dopamine, a common neurotransmitter — within the mushroom body do not encode a single signal, but rather perform a more complex computation of environmental conditions.

“We found that dopamine neurons process multiple inputs to generate multiple outputs — the same set of nerves process sensory information and reward-avoidance learning,” said TSRI Assistant Professor Seth Tomchik. “This discovery helps lay the groundwork to better understand how information is processed in the brain. A similar set of neurons is involved in behavior preferences in humans — from basic rewards to more complex learning and memory.”

Using imaging techniques that allow scientists to visualize neuron activity in real time, the study illuminated the response of dopaminergic neurons to changes in temperature. The behavioral roles were then examined by silencing various subsets of these neurons. Flies were tested using a temperature gradient plate; the flies moved from one place to another to express their temperature preferences.

As it turns out, genetic silencing of dopaminergic neurons innervating the mushroom body substantially reduces cold avoidance behavior. “If you give the fly a choice, it will pick San Diego weather every time,” Tomchik said, “but if you shut down those nerves, they suddenly don’t mind being in Minnesota.”

The study also showed dopaminergic neurons respond to cooling with sudden a burst of activity at the onset of a drop in temperature, before settling down to a lower steady-state level. This initial burst of dopamine could function to increase neuronal plasticity — the ability to adapt — during periods of environmental change when the organism needs to acquire new associative memories or update previous associations with temperature changes.

The study, “Dopaminergic Neurons Encode a Distributed, Asymmetric Representation of Temperature in Drosophila,” was supported by the National Institute of Mental Health of the National Institutes of Health (grant number K99 MH092294).

 

Story Source:

The above story is reprinted from materials provided byScripps Research Institute.

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


Scripps Research Institute (2013, January 29). How brain cells shape temperature preferences. ScienceDaily. Retrieved January 31, 2013, from http://www.sciencedaily.com/releases/2013/01/130129190251.htm