Posts tagged psychology
Articles and news from the latest research reports.
Brain’s Code for Visual Working Memory Deciphered in Monkeys
The brain holds in mind what has just been seen by synchronizing brain waves in a working memory circuit, an animal study supported by the National Institutes of Health suggests. The more in-sync such electrical signals of neurons were in two key hubs of the circuit, the more those cells held the short-term memory of a just-seen object.
Charles Gray, Ph.D., of Montana State University, Bozeman, a grantee of NIH’s National Institute of Mental Health (NIMH), and colleagues, report their findings Nov. 1, 2012, online, in the journal Science Express.
“This work demonstrates, for the first time, that there is information about short term memories reflected in in-sync brainwaves,” explained Gray.
“The Holy Grail of neuroscience has been to understand how and where information is encoded in the brain. This study provides more evidence that large scale electrical oscillations across distant brain regions may carry information for visual memories,” said NIMH director Thomas R. Insel, M.D.
Prior to the study, scientists had observed synchronous patterns of electrical activity between the two circuit hubs after a monkey saw an object, but weren’t sure if the signals actually represent such short-term visual memories in the brain. Rather, it was thought that such neural oscillations might play the role of a traffic cop, directing information along brain highways.
Not Just Parroting Back: Alex the Parrot Knew His Numbers
Alex, an African grey parrot who died 5 years ago and was known for his ability to use English words, also understood a great deal about numbers. In a new study in this month’s Cognition, scientists show that Alex correctly inferred the relationship between cardinal and ordinal numbers, an ability that has not previously been found in any species other than humans. After learning the cardinal numbers—or exact values—of one to six, Alex was taught the ordinal values (the position of a number in a list) of seven and eight—that is, he learned that six is less than seven, and seven is less than eight. He was never taught the cardinal values of seven and eight—but when tested on this, he passed with flying colors, apparently inferring, for instance, that the sound “seven” meant six plus one. In the video above of one of these experiments, comparative psychologist Irene Pepperberg of Harvard University asks Alex to pick out the set of colored blocks that equal the number seven. Play the video to hear his answer.
Researchers identify gene required for nerve regeneration
A gene that is associated with regeneration of injured nerve cells has been identified by scientists at Penn State and Duke University. The team, led by Melissa Rolls, an assistant professor of biochemistry and molecular biology at Penn State, has found that a mutation in a single gene can entirely shut down the process by which axons — the parts of the nerve cell that are responsible for sending signals to other cells — regrow themselves after being cut or damaged. “We are hopeful that this discovery will open the door to new research related to spinal-cord and other neurological disorders in humans,” Rolls said. The journal Cell Reports published an early online copy of the paper (Nov. 1), and also will include the paper in the monthly issue of the journal, which will be published Nov. 29.
LSUHSC research identifies new therapeutic target for Alzheimer’s disease
Research led by Chu Chen, PhD, Associate Professor of Neuroscience at LSU Health Sciences Center New Orleans, has identified an enzyme called Monoacylglycerol lipase (MAGL) as a new therapeutic target to treat or prevent Alzheimer’s disease. The study was published online November 1, 2012 in the Online Now section of the journal Cell Reports.
The research team found that inactivation of MAGL, best known for its role in degrading a cannabinoid produced in the brain, reduced the production and accumulation of beta amyloid plaques, a pathological hallmark of Alzheimer’s disease. Inhibition of this enzyme also decreased neuroinflammation and neurodegeneration, and improved plasticity of the brain, learning and memory.
"Our results suggest that MAGL contributes to the cause and development of Alzheimer’s disease and that blocking MAGL represents a promising therapeutic target," notes Dr. Chu Chen, who is also a member of the Department of Otolaryngology at LSU Health Sciences Center New Orleans.
The researchers blocked MAGL with a highly selective and potent inhibitor in mice using different dosing regimens and found that inactivation of MAGL for eight weeks was sufficient to decrease production and deposition of beta amyloid plaques and the function of a gene involved in making beta amyloid toxic to brain cells. They also measured indicators of neuroinflammation and neurodegeneration and found them suppressed when MAGL was inhibited. The team discovered that not only did the integrity of the structure and function of synapses associated with cognition remain intact in treated mice, but MAGL inactivation appeared to promote spatial learning and memory, measured with behavioral testing.
Alzheimer’s disease is a neurodegenerative disorder characterized by accumulation and deposition of amyloid plaques and neurofibrillary tangles, neuroinflammation, synaptic dysfunction, progressive deterioration of cognitive function and loss of memory in association with widespread nerve cell death. The most common cause of dementia among older people, more than 5.4 million people in the United States and 36 million people worldwide suffer with Alzheimer’s disease in its various stages. Unfortunately, the few drugs that are currently approved by the Food and Drug Administration have demonstrated only modest effects in modifying the clinical symptoms for relatively short periods, and none has shown a clear effect on disease progression or prevention.
"There is a great public health need to discover new therapies to prevent and treat this devastating disorder," Dr. Chen concludes. The research was supported by grants from the National Institutes of Health. In addition to scientists from LSU Health Sciences Center New Orleans, the research team also included investigators from the Massachusetts Institute of Technology.
(Source: eurekalert.org)
Music in Our Ears: The Biological Bases of Musical Timbre Perception
Timbre is the attribute of sound that allows humans and other animals to distinguish among different sound sources. Studies based on psychophysical judgments of musical timbre, ecological analyses of sound’s physical characteristics as well as machine learning approaches have all suggested that timbre is a multifaceted attribute that invokes both spectral and temporal sound features. Here, we explored the neural underpinnings of musical timbre. We used a neuro-computational framework based on spectro-temporal receptive fields, recorded from over a thousand neurons in the mammalian primary auditory cortex as well as from simulated cortical neurons, augmented with a nonlinear classifier. The model was able to perform robust instrument classification irrespective of pitch and playing style, with an accuracy of 98.7%. Using the same front end, the model was also able to reproduce perceptual distance judgments between timbres as perceived by human listeners. The study demonstrates that joint spectro-temporal features, such as those observed in the mammalian primary auditory cortex, are critical to provide the rich-enough representation necessary to account for perceptual judgments of timbre by human listeners, as well as recognition of musical instruments.
Rethinking reading: UI study breaks new ground in reading development research
Many educators have long believed that when words differ on only one sound, early readers can learn the rules of phonics by focusing on what is different between the words. This is thought to be a critical gateway to reading words and sentences.
But scientists at the University of Iowa are turning that thinking on its head. A recent study published in Developmental Psychology shows certain kinds of variation in words may help early readers learn better. When children see the same phonics regularities, embedded in words with more variation, they may learn these crucial early reading skills better. What might appear to make learning a more difficult task—learning about letter-sound relationships from words with more variation—actually leads to better learning.
Doctoral student Keith Apfelbaum and associate professors Bob McMurray and Eliot Hazeltine of the Department of Psychology in the UI College of Liberal Arts and Sciences (CLAS) studied 224 first-grade students in the West Des Moines, Iowa school system over a period of three months. The group used a version of an online supplementary curriculum called Access Code.
Access Code was developed by Foundations in Learning, a company founded by Carolyn Brown and Jerry Zimmermann. Brown and Zimmermann earned their doctorates from and are now adjunct faculty in the Department of Communication Sciences and Disorders, also in CLAS. Based on the Varied Practice Model, which helps children master early reading skills like phonics, the research team used Access Code to conduct the study directly in the classroom.
An elephant that speaks Korean
An Asian elephant named Koshik can imitate human speech, speaking words in Korean that can be readily understood by those who know the language. The elephant accomplishes this in a most unusual way: he vocalizes with his trunk in his mouth.
The elephant’s vocabulary consists of exactly five words, researchers report on November 1 in Current Biology, a Cell Press publication. Those include “annyong” (“hello”), “anja” (“sit down”), “aniya” (“no”), “nuo” (“lie down”), and “choah” (“good”). Ultimately, Koshik’s language skills may provide important insights into the biology and evolution of complex vocal learning, an ability that is critical for human speech and music, the researchers say.
"Human speech basically has two important aspects, pitch and timbre," says Angela Stoeger of the University of Vienna. "Intriguingly, the elephant Koshik is capable of matching both pitch and timbre patterns: he accurately imitates human formants as well as the voice pitch of his trainers. This is remarkable considering the huge size, the long vocal tract, and other anatomical differences between an elephant and a human."
This is your brain on politics
With the U.S. presidential election just days away, new research from the University of South Carolina provides fresh evidence that choosing a candidate may depend more on our biological make-up than a careful analysis of issues.
That’s because the brains of self-identified Democrats and Republicans are hard-wired differently and may be naturally inclined to hold varying, if not opposing, perceptions and values. The USC study, which analyzed MRI scans of 24 USC students, builds on existing research in the emerging field of political neuroscience.
“The differences are significant and real,” said lead researcher Roger D. Newman-Norlund, an assistant professor of exercise science in the Arnold School of Public Health and the director of USC’s new Brain Simulation Laboratory.
The study focused on the mirror neuron system, a network of brain areas linked to a host of social and emotional abilities. After declaring their political affiliation, The subjects were given questionnaires designed to gauge their attitudes on a range of select political issues. Next, they were given “resting state” MRIs which made it possible to analyze the strength of connections within the mirror neuron system in both the left and right hemispheres of their brains; specifically the inferior frontal gyrus, supramarginal gyrus and angular gyrus.
The results found more neural activity in areas believed to be linked with broad social connectedness in Democrats (friends, the world at-large) and more activity in areas linked with tight social connectedness in the Republicans (family, country). In some ways the study confirms a stereotype about members of the two parties — Democrats tend to be more global and Republicans more America-centric — but it actually runs counter to other recent research indicating Democrats enjoyed a virtual lock on caring for others.
Biology and ideology: The anatomy of politics
An increasing number of studies suggest that biology can exert a significant influence on political beliefs and behaviours. Biological factors including genes, hormone levels and neurotransmitter systems may partly shape people’s attitudes on political issues such as welfare, immigration, same-sex marriage and war. And shrewd politicians might be able to take advantage of those biological levers through clever advertisements aimed at voters’ primal emotions.
Many of the studies linking biology to politics remain controversial and unreplicated. But the overall body of evidence is growing and might alter how people think about their own and others’ political attitudes.
“People are proud of their political beliefs,” says John Hibbing, a political scientist at the University of Nebraska–Lincoln. “We tend to think they’re the result of some rational responses to the world around us.” But in fact, a combination of genes and early experiences may predispose people to perceive and respond to political issues in certain ways. Recognizing that could help the public and politicians to develop more respect for those with opposing viewpoints.
Brain May ‘See’ More Than the Eyes, Study Indicates
Vision may be less important to “seeing” than is the brain’s ability to process points of light into complex images, according to a new study of the fruit fly visual system currently published in the online journal Nature Communications.
University of Virginia researchers have found that the very simple eyes of fruit fly larvae, with only 24 total photoreceptors (the human eye contains more than 125 million), provide just enough light or visual input to allow the animal’s relatively large brain to assemble that input into images.
“It blows open how we think about vision,” said Barry Condron, a neurobiologist in U.Va.’s College of Arts & Sciences, who oversaw the study. “This tells us that visual input may not be as important to sight as the brain working behind it. In this case, the brain apparently is able to compensate for the minimal visual input.”
Condron’s graduate students, Elizabeth Daubert, Nick Macedonia and Catherine Hamilton, conducted a series of experiments to test the vision of fruit fly larvae after they noticed an interesting behavior of the animals during a different study of the nervous system. They found that when a larva was tethered to the bottom of a petri dish, other larvae were attracted to it as it wiggled attempting to free itself.
The animals apparently saw the writhing motion and were attracted to it, willingly traveling toward it. After several further experiments to understand how they sensed the motion, the researchers learned that the nearly blind animals likely were seeing the action, by wagging their heads side-to-side in a scanning motion to detect it, rather than by only hearing it or feeling vibration or by smelling the trapped larva. This was a surprise because of the very simple and limited vision of fruit fly larvae.