Posts tagged science
Articles and news from the latest research reports.
Babies’ ability to detect complex rules in language outshines that of adults
New research examining auditory mechanisms of language learning in babies has revealed that infants as young as three months of age are able to automatically detect and learn complex dependencies between syllables in spoken language. By contrast, adults only recognized the same dependencies when asked to actively search for them. The study by scientists at the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig also highlights the important role of basic pitch discrimination abilities for early language development.
Cross a crow and it’ll remember you for years. Crows and humans share the ability to recognize faces and associate them with negative, as well as positive, feelings. The way the brain activates during that process is something the two species also appear to share, according to new research being published this week.
"The regions of the crow brain that work together are not unlike those that work together in mammals, including humans," said John Marzluff, University of Washington professor of environmental and forest sciences. "These regions were suspected to work in birds but not documented until now.
"For example it appears that birds have a region of their brain that is analogous to the amygdala of mammals," he said. "The amygdala is the region of the vertebrate brain where negative associations are stored as memories. Previous work primarily concerned its function in mammals while our work shows that a similar system is at work in birds. Our approach could be used in other animals – such as lizards and frogs – to see if the process is similar in those vertebrates as well."
Marzluff is the lead author of a paper being published the week of Sept. 10 in the online edition of the Proceedings of the National Academy of Sciences.
How does one’s experience of an event get translated into a memory that can be accessed months, even years later?
A team led by University of Pennsylvania scientists has come closer to answering that question, identifying key molecules that help convert short-term memories into long-term ones. These proteins may offer a target for drugs that can enhance memory, alleviating some of the cognitive symptoms that characterize conditions including schizophrenia, depression and Parkinson’s and Alzheimer’s diseases.
“There are many drugs available to treat some of the symptoms of diseases like schizophrenia,” Abel -Penn’s Brush Family Professor of Biology- said, “but they don’t treat the cognitive deficits that patients have, which can include difficulties with memory. This study looks for more specific targets to treat deficits in cognition.”
Published in the Journal of Clinical Investigation, the study focused on a group of proteins called nuclear receptors, which have been implicated in the regulation of a variety of biological functions, including memory formation.
Researchers have discovered how to store diverse forms of artificial short-term memories in isolated brain tissue. The advance paves the way for future research to identify the specific brain circuits that allow humans to form short-term memories.
Using isolated pieces of rodent brain tissue, the researchers demonstrated that they could form a memory of which one of four input pathways was activated. The neural circuits contained within small isolated sections of the brain region called the hippocampus maintained the memory of stimulated input for more than 10 seconds. The information about which pathway was stimulated was evident by the changes in the ongoing activity of brain cells.
"The type of activity we triggered in isolated brain sections was similar to what other researchers have demonstrated in monkeys taught to perform short-term memory tasks," according to Mr. Hyde. "Both types of memory-related activity changes typically lasted for 5-10 seconds."
The researchers also demonstrated that they could generate memories for specific contexts, such as whether a particular pathway was activated alone or as part of a sequence of stimuli to different inputs. Changes in ongoing activity of hippocampal neurons accurately distinguished between two temporal sequences, akin to humans recognizing the difference between two different song melodies. The artificial memories Dr. Strowbridge’s group created in the hippocampus continued to recognize each sequence even when the interval between stimuli was changed.
It was a quiet Thursday afternoon when AS, a 68-year-old woman from a suburb of Chicago, awakened from a nap to the realization that something was terribly wrong.
When AS woke from her nap, she couldn’t find where doors or cabinets were. She couldn’t name or distinguish familiar household objects. She couldn’t read a book or the numbers on her telephone. She couldn’t see where the bedroom wall ended and the door began. Yet when she saw an ophthalmologist, her vision with glasses was 20/20. She and her husband left the ophthalmologist’s office with a referral to see a neurologist, and “wondering what sort of ailment could rob her of her ability to see the bathroom sink, while leaving her with what we typically think of as perfect vision.”
Balint’s syndrome is named after Austro-Hungarian neurologist Rezső Bálint, who first described it. The condition is caused by one or more strokes in certain regions of the brain. It causes three deficits: Difficulty initiating voluntary eye movements (such as following a physician’s finger); inaccurate arm pointing (a patient can see an object, but is unable to pick it up); and constriction of the visual field (ask a patient to look at a parking lot, and all she sees is a lamp post or a car.)
A Loyola University Medical Center paper “is an attempt to inform both our clinical and subjective understandings of Balint’s syndrome through narratives of two patients suffering from this rare and unique neurological disorder.”
Cocaine-withdrawal emotion mechanism discovered
Washington State University researchers have found a cellular mechanism that contributes to the lack of motivation and negative emotions of a cocaine addict going through withdrawal. Their discovery, published in the latest Proceedings of the National Academy of Sciences, offers a deeper look into the cellular and behavioral implications of addiction.
Bradley Winters, lead author of the PNAS paper and a freshly minted WSU doctor of neuroscience, says he, his major advisor Yan Dong, and colleagues at WSU, the University of Pittsburgh and the European Neuroscience Institute focused on cells that produce a signaling molecule called cannabinoid receptor 1, or CB1. Its main function is regulating the communication between nerve cells related to the functions like memory, motor control, perception, mood and appetite. Those same functions are affected by THC, the cannabinoid in its namesake cannabis, or marijuana.
"These receptors are not here just to make marijuana fun,” says Winters. "Their main function is changes in how nerve cells communicate with each other.”
The researchers studied the CB1 cells by producing a line of mice in which the cells that make CB1 were labeled fluorescently. The researchers could then identify the cells and target them with glass pipettes 1/100th the width of a human hair and record electrical currents they use to communicate with other nerve cells.
The CB1 cells act like brakes, slowing down activity in a brain region called the nucleus accumbens, which governs emotion and motivation.
"Cocaine causes profound cellular changes in the nucleus accumbens, but no one has ever looked at this type of cell, and these cells are important because they help organize the output,” says Winters.
The researchers found that cocaine increases the excitability of the CB1 cells, in effect stepping on the brakes of emotion and motivation. When an addict is high on cocaine, the brakes are struggling to slow things down. The problem is, they stay on even when the cocaine has worn off.
"As you do cocaine, it speeds everything up, pushing you to a highly rewarding emotional state,” says Winters. "It is kind of like going down a steep hill so you have to start riding that brake really hard. But then after the cocaine wears off and the hill levels out, you’re still riding that brake just as hard. Now you’re going down a regular, low-grade hill but you’re going 2 mph because your foot is still jammed on the brake.”
The result is a drag on the emotions and motivation of an addict in withdrawal—a drag that could be linked to sluggish activation of the nucleus accumbens.
"That state is like, ‘I feel terrible and I don’t want to do anything,’” says Winters. "You have the high and the crashing low and this low that you feel is what brings you back to the drug because you want to feel better and the drug is the only thing you feel motivation for.”
(Source: news.wsu.edu)
![Researchers have identified a novel mechanism that helps explain the power of placebos and nocebos.
Described in the Sept. 10 on-line issue of the Proceedings of the National Academy of Sciences (PNAS), the new findings demonstrate that the placebo effect can be activated outside of conscious awareness, and provide an explanation for how patients can show clinical improvement even when they receive treatments devoid of active ingredients or of known therapeutic efficacy.
"In this study, we used a novel experimental design and found that placebo and nocebo [negative placebo] effects rely on brain mechanisms that are not dependent on cognitive awareness," explains first author Karin Jensen, PhD, of the Department of Psychiatry and the Martinos Center for Biomedical Imaging at Massachusetts General Hospital (MGH) and the Program in Placebo Studies (PiPS) at Beth Israel Deaconess Medical Center/Harvard Medical School. "A person can have a placebo or nocebo response even if he or she is unaware of any suggestion of improvement or anticipation of getting worse."](http://41.media.tumblr.com/tumblr_ma6plh1OZN1rog5d1o1_500.jpg)
Researchers have identified a novel mechanism that helps explain the power of placebos and nocebos.
Described in the Sept. 10 on-line issue of the Proceedings of the National Academy of Sciences (PNAS), the new findings demonstrate that the placebo effect can be activated outside of conscious awareness, and provide an explanation for how patients can show clinical improvement even when they receive treatments devoid of active ingredients or of known therapeutic efficacy.
"In this study, we used a novel experimental design and found that placebo and nocebo [negative placebo] effects rely on brain mechanisms that are not dependent on cognitive awareness," explains first author Karin Jensen, PhD, of the Department of Psychiatry and the Martinos Center for Biomedical Imaging at Massachusetts General Hospital (MGH) and the Program in Placebo Studies (PiPS) at Beth Israel Deaconess Medical Center/Harvard Medical School. "A person can have a placebo or nocebo response even if he or she is unaware of any suggestion of improvement or anticipation of getting worse."
Scientists are growing ears, bone and skin in the lab, and doctors are planning more face transplants and other extreme plastic surgeries. Around the country, the most advanced medical tools that exist are now being deployed to help America’s newest veterans and wounded troops.
Top Image: A research engineer at the Laboratory for Tissue Engineering and Organ Fabrication at Massachusetts General Hospital, displays a titanium frame designed for the reconstruction of a human ear, left, and a three dimensional plastic ear model, right, at the lab, in Boston.
Bottom Image: A chart provided by the Laboratory for Tissue Engineering and Organ Fabrication at Massachusetts General Hospital, depicts the progression, from left to right, of implanted tissue engineered for ear development and construction, at the lab in Boston.
(Source: spokesman.com)
Muscles that do nothing can keep you warm and thin
Muscles that burn energy without contracting have yielded new clues about how the body retains a constant temperature – and they may provide new targets for combating obesity.
Traditionally, the body’s main thermostat was thought to be brown fat. It raids the body’s white fat stores in cold conditions to burn energy and keep the body warm.
Muscles also play a role in keeping the body warm by contracting and triggering the shiver response – but this is only a short-term fix because prolonged shivering damages muscles. Now it seems that muscles have another way to turn up the heat.
"Our findings demonstrate for the first time that muscle, which accounts for 40 per cent of body weight in humans, can generate heat independent of shivering," says Muthu Periasamy of Ohio State University in Columbus.
Sarcolipin: idle body’s thermostat (Image: David Trood/Stone/Getty)
Surviving the chill
Through experiments on mice that had their usual thermostat – brown fat – surgically removed, Periasamy and his colleagues proved that a protein called sarcolipin helps muscle cells keep the body warm by burning energy, almost like an idling motor car, even if the muscles do not contract.
All of the mice had their brown fat removed, but some of them had been genetically engineered to lack sarcolipin too. These rodents could not survive when held at 4 °C, and died of hypothermia within 10 hours. By contrast, mice that could make sarcolipin were able to survive the chilly temperatures and maintained their core body temperature – despite having no brown fat.
Periasamy also showed that an inability to make sarcolipin made mice 33 per cent heavier than normal when fed a high-fat diet. This suggests that idling muscles might also help combat obesity by burning off excess energy. The search is now on for drugs that perform the same role, triggering idling muscles to burn off excess fat.
"The most interesting finding is that mice unable to make sarcolipin are more susceptible to obesity," says Andy Whittle of the University of Cambridge, who is testing spicy dietary treatments to ramp up the fat-burning activity of brown fat. "The research demonstrates that muscle is an important component even in mice, which have comparatively more brown fat than humans. In humans, burning fat in muscle is likely to be even more important for proper energy balance."
(Source: newscientist.com)
A new study by University of North Carolina School of Medicine pediatrics researchers finds a surprising difference in the eating habits of overweight children between ages 9 and 17 years compared to those younger than 9.
Younger children who are overweight or obese consume more calories per day than their healthy weight peers. But among older overweight children the pattern is reversed: They actually consume fewer calories per day than their healthy weight peers.
How to explain such a seemingly counterintuitive finding?
“Children who are overweight tend to remain overweight,” said Asheley Cockrell Skinner, PhD, assistant professor of pediatrics at UNC and lead author of the study published online Sept. 10, 2012 by the journal Pediatrics.
“So, for many children, obesity may begin by eating more in early childhood. Then as they get older, they continue to be obese without eating any more than their healthy weight peers,” Skinner said. “One reason this makes sense is because we know overweight children are less active than healthy weight kids. Additionally, this is in line with other research that obesity is not a simple matter of overweight people eating more — the body is complex in how it reacts to amount of food eaten and amount of activity.”