Researchers supported by the Wellcome Trust have discovered that we use a different part of our brain to learn about social hierarchies than we do to learn ordinary information. The study provides clues as to how this information is stored in memory and also reveals that you can tell a lot about how good somebody is likely to be at judging social rank by looking at the structure of their brain.
Primates (and people) are remarkably good at ranking each other within social hierarchies, a survival technique that helps us to avoid conflict and select advantageous allies. However, we know surprisingly little about how the brain does this.
The team at the UCL Institute for Cognitive Neuroscience used brain imaging techniques to investigate this in twenty six healthy volunteers.
Participants were asked to play a simple science fiction computer game where they would be acting as future investors. In the first phase they were told they would first need to learn about which individuals have more power within a fictitious space mining company (the social hierarchy), and then which galaxies have more precious minerals (non-social information).
Whilst they were taking part in the experiments, the team used functional magnetic resonance imaging (fMRI) to monitor activity in their brains. Another MRI scan was also taken to look at their brain structure.
Their findings reveal a striking dissociation between the neural circuits used to learn social and non-social hierarchies. They observed increased neural activity in both the amygdala and the hippocampus when participants were learning about the hierarchy of executives within the fictitious space mining company. In contrast, when learning about the non-social hierarchy, relating to which galaxies had more mineral, only the hippocampus was recruited.
(Source: eurekalert.org)
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Going with Your Gut
Decision-making is an inevitable part of the human experience, and one of the most mysterious. For centuries, scientists have studied how we go about the difficult task of choosing A or B, left or right, North or South — and how both instinct and intellect figure into the process. Now new research indicates that the old truism “look before you leap” may be less true than previously thought.
In a behavioral experiment, Prof. Marius Usher of Tel Aviv University’s School of Psychological Sciences and his fellow researchers found that intuition was a surprisingly powerful and accurate tool. When forced to choose between two options based on instinct alone, the participants made the right call up to 90 percent of the time.
The results of their study were recently published in the journal PNAS.
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The brain of OCD sufferers is more active when faced with a moral dilemma
Patients with obsessive-compulsive disorder are characterised by persistent thoughts and repetitive behaviours. A new study reveals that sufferers worry considerably more than the general population in the face of morality problems.
Along with the help of experts from the Barcelona’s Hospital del Mar and the University of Melbourne (Australia), researchers at the Hospital de Bellvitge in Barcelona have proven that patients with obsessive-compulsive disorder, known as OCD, are more morally sensitive.
"Faced with a problem of this type, people suffering from this type of anxiety disorder show that they worry considerably more," as explained to SINC by Carles Soriano, researcher at the Catalan hospital and one of the lead authors of the work published in the journal Archives of General Psychiatry.
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New, Improved Mouse Model of Human Alzheimer’s May Enable Drug Discovery
Researchers at the University of Illinois at Chicago College of Medicine have developed a transgenic mouse that carries a human gene known to increase risk of Alzheimer’s 15-fold. This new mouse mimics the genetics of the human disease more closely than any of the dozen existing mouse models and may prove more useful in the development of candidate drugs to prevent or treat the disease.
The new mouse model provides new evidence for the earliest cause of Alzheimer’s, researchers report in a study to be published in the December issue of the Journal of Biological Chemistry and now available online.
The model is a cross between an existing transgenic Alzheimer’s mouse and a mouse carrying fully human apoE, a gene that in one of its three variants, apoE4, is the greatest genetic risk factor for Alzheimer’s in the human population.
(Source: tigger.uic.edu)
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Wrens Teach Eggs to Sing
Mothers usually set about teaching their offspring the moment they’re born. But the females of one Australian bird can’t wait that long.
Superb fairy-wren (Malurus cyaneus) mothers sing to their unhatched eggs to teach the embryo inside a ‘password’ — a single unique note — which the nestlings must later incorporate into their begging calls if they want to get fed.
The trick allows fairy-wren parents to distinguish between their own offspring and those of the two cuckoo species that frequently invade their nests. The female birds also teach their mates the password.
Fairy-wrens were known to discriminate against cuckoo nestlings on the basis of their foreign begging calls, says Sonia Kleindorfer, an animal behaviorist at Flinders University in Adelaide, who led the work. But it wasn’t known that wren nestlings learned the passwords before hatching.
“It has never been shown before that there is actually learning in the embryo stages,” says Kleindorfer. The finding, published today in Current Biology, has the potential to open up new lines of enquiry into prenatal learning in systems other than parasite-host relationships and in other animals — it could occur anywhere where it’s a benefit, she adds.
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Scripps Florida Scientists Uncover Secrets of How Intellect and Behavior Emerge During Childhood
Scientists from the Florida campus of The Scripps Research Institute (TSRI) have shown that a single protein plays an oversized role in intellectual and behavioral development. The scientists found that mutations in a single gene, which is known to cause intellectual disability and increase the risk of developing autism spectrum disorder, severely disrupts the organization of developing brain circuits during early childhood. This study helps explain how genetic mutations can cause profound cognitive and behavioral problems.
The study was published in the November 9, 2012, issue of the journal Cell.
The genetic mutations that cause developmental disorders, such as intellectual disability and autism spectrum disorder, commonly affect synapses, the junctions between two nerve cells that are part of the brain’s complex electro-chemical signaling system. A substantial percentage of children with severe intellectual and behavioral impairments are believed to harbor single mutations in critical neurodevelopmental genes. Until this study, however, it was unclear precisely how pathogenic genetic mutations and synapse function were related to the failure to develop normal intellect.
“In this study, we did something no one else had done before,” said Gavin Rumbaugh, a TSRI associate professor who led the new research. “Using an animal model, we looked at a mutation known to cause intellectual disability and showed for the first time a causative link between abnormal synapse maturation during brain development and life-long cognitive disruptions commonly seen in adults with a neurodevelopmental disorder.”
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Feel-good hormone helps to jog the memory
The feel-good hormone dopamine improves long-term memory. This is the finding of a team lead by Emrah Düzel, neuroscientist at the German Center for Neurodegenerative Diseases (DZNE) and the University of Magdeburg. The researchers investigated test subjects ranging in age from 65 to 75 years, who were given a precursor of dopamine. Treated subjects performed better in a memory test than a comparison group, who had taken a placebo. The study provides new insights into the formation of long lasting memories and also has implications for understanding why memories fade more rapidly following the onset of Alzheimer’s disease. The results appear in the Journal of Neuroscience.
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Pressure switch inside the head
An increase in cerebral pressure may cause dementia and could destroy the brain. Companies have been seeking to find monitoring sensors that can be implanted into the brain, and read from outside the body. A tiny sensor may provide the help needed.
To this day it remains a mystery why the cerebral pressure in certain people suddenly increases. The consequences, however, are better understood: The blood circulation is disrupted and after a while parts of the brain may die off, similar to what occurs in a stroke. This is how dementia takes its insidious path. Experts estimate that up to ten percent of all cases of dementia in Europe can be attributed to rising blood pressure in the brain. Still, making the diagnosis is tough. People with a heightened susceptibility to a rise in intracranial pressure must be treated with intensive medical care today. A probe is inserted that goes from the outside through the skullcap to the brain. The cable keeps the patient connected to the measuring apparatus. Since cerebral pressure fluctuates, it takes extensive measurements in order to reach a definitive diagnosis of this disease. Patients therefore have to stay in hospital typically for several days, and sometimes even weeks.
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Brain and brain waves in epilepsy
Caption: 3D magnetic resonance imaging (MRI) scan of a brain (seen from the front), overlaid with an electroencephalogram (EEG) of a 17-year-old’s brain during an epileptic episode (chaotic brain activity). This EEG shows generalized epilepsy, where the whole brain cortex is affected: all the EEG traces show chaotic brain waves. Epilepsy can have many causes, but when the cause is unknown, as here, it is called essential epilepsy. An EEG measures the electrical activity of the brain using electrodes attached to the scalp. The electrode locations are labelled at far left, on diagrams of the head seen from above, with the front of the head at left.
Credit: SOVEREIGN, ISM/SCIENCE PHOTO LIBRARY
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