Posts tagged science
Articles and news from the latest research reports.
Have you ever wondered why women stay pregnant for nine months? For decades, anthropologists have explained the timing of human gestation and birth as a balance between two constraints: the size of a women’s hips and the size of a newborn’s brain. But new research says that’s not the case. Instead, the timing of childbirth occurs when women’s bodies can no longer keep up with the energy demands of pregnancy. That happens at around nine months, Holly Dunsworth of the University of Rhode Island and colleagues report online August 27 in the Proceedings of the National Academy of Sciences.
FYI: How Long Can a Brain Live in a Dish?
Brain in a Dish Tony Latham/Getty Images
Scientists have isolated the brains of dogs, cats and monkeys and kept them alive for short periods in one way or another. But the most successful “whole-brain preparation” of a mammal was developed in the mid-1980s. A neuroscientist at NYU Langone Medical Center named Rodolfo Llinás came up with a way to keep the brain of a young guinea pig alive in a fluid-filled tank for the length of a standard workday.
To begin with, Llinás and his colleagues anesthetized the animal, opened up its chest, and cooled its brain by injecting cold saline into the ascending aorta. After extracting the brain from the skull, the researchers tied it to the bottom of the tank with some thread and surrounded it with glass beads, so it wouldn’t slide around. They kept the brain alive by injecting a solution of sugar, electrolytes and dissolved oxygen (among other ingredients) directly into one of its vertebral arteries. Guinea pigs turned out to be a good animal for this preparation because their vertebral arteries are accessible and because their brains are small enough to handle—but not too small for fine dissection.
Llinás’s preparation allows for the brain to be poked with electrodes, injected with drugs, or otherwise studied from any angle with all its circuitry intact. But there are only a handful of labs that still use this approach; many physiologists do experiments with whole, living animals or slices of brain tissue kept alive in a dish instead. “The preparation is difficult and expensive to maintain as a model system for brain study,” says University of Alberta neuroscientist Clayton Dickson, who learned the method in Italy but has since abandoned it. “It requires a dedicated, continuous and persistent research team to keep it going.”
Source: PopSci
The speed at which we drink alcohol may be influenced by the shape of the glass we drink from, according to new research from the University of Bristol, published in PLoS ONE. This could be a target to help control the problematic levels of drunkenness that are becoming increasingly common in our society.
Unsure robots make better teachers than know-alls
The best way to learn is to teach. Now a classroom robot that helps Japanese children learn English has put that old maxim to the test.
(Image: Sinopix/Rex Features)
Shizuko Matsuzoe and Fumihide Tanaka at the University of Tsukuba, Japan, set up an experiment to find out how different levels of competence in a robot teacher affected children’s success in learning English words for shapes.
They observed how 19 children aged between 4 and 8 interacted with a humanoid Nao robot in a learning game in which each child had to draw the shape that corresponded to an English word such as ‘circle’, ‘square’, ‘crescent’, or ‘heart’.
The researchers operated the robot from a room next to the classroom so that it appeared weak and feeble, and the children were encouraged to take on the role of carers. The robot could then either act as an instructor, drawing the correct shape for the child, or make mistakes and act as if it didn’t know the answer.
When the robot got a shape wrong, the child could teach the robot how to draw it correctly by guiding its hand. The robot then either “learned” the English word for that shape or continued to make mistakes.
Robot learner aids learning
Matsuzoe and Tanaka found that the children did best when the robot appeared to learn from them. This also made the children more likely to want to continue learning with the robot. The researchers will present their results at Ro-Man - an international symposium on robot and human interactive communication - in September.
"Anything that gets a person more actively engaged and motivated is going to be beneficial to the learning process," says Andrea Thomaz , director of the Socially Intelligent Machines lab at the Georgia Institute of Technology in Atlanta. "So needing to teach the robot is a great way of doing that."
The idea of students learning by teaching also agrees with a lot of research in human social learning, she says. The process of teaching a robot is akin to what happens in peer-to-peer learning, where students teach each other or work in groups to learn concepts – common activities in most classrooms.
Source: NewScientist
An open platform revolutionizes biomedical-image processing
Ignacio Arganda, a young researcher from San Sebastián de los Reyes (Madrid) working for the Massachusetts Institute of Technology (MIT) is one of the driving forces behind Fiji, an open source platform that allows for application sharing as a way of improving biomedical-image processing. Arganda explains to SINC that Fiji, which has enjoyed the voluntary collaboration of some 20 developers from all over the world, has become a de facto standard that assists laboratories and microscope companies in their development of more precise products.
Ignacio Arganda is a postdoctoral researcher at the Laboratory of Computational Neuroscience of the Massachusetts Institute of Technology (MIT). Along with a group of researchers he implemented Fiji, a platform that allows for applications to be shared in order to improve and advance in the processing and analysis of biomedical imaging. “All of this in open source,” outlines Arganda.
The platform was built from a previous one, ImageJ, which was well known in the industry at the time. ImageJ was not an open source platform but it was publicly accessible. According to Arganda, it had the advantage that any person working in medical imaging could easily create small software applications to resolve their particular problems and then incorporate it into the platform by means of a plug-in (an application which is linked to another providing a new or specific function).
Nonetheless, the researcher adds that this platform became too chaotic with applications of all kinds, some of which were not related to biomedical-imaging. It also began being used to handle astronomical images, in video tracking, etc. “There was a significant lack of control and structure,” he says.
Therefore, “in a spontaneous manner and without any help” this group of researchers decided to create the new open source platform that could put order to that already in place, reusing what was of interest and useful in their work.
"We created a webpage organised like Wikipedia where people could contribute and use their knowledge to help others. To our surprise, it became very popular," he ensures. According to Ignacio Aranda, Fiji currently has 127,000 unique visits (20,000 each month).
(Source: eurekalert.org)
New insights into placebo effect
Mathematical models developed by scientists at the University of Bristol are providing new insights into why the placebo effect exists and when it should occur. Their research is published in the journal of Evolution and Human Behaviour.
A placebo – such as a sugar pill – is a treatment which is not effective through its direct action on the body but works because of its effect on the patient’s beliefs. But if individuals are capable of recovering without external aid, why do they rely on an external cue? In other words, why have individuals not evolved the ability to get better immediately on their own?
Members of the Modelling Animal Decisions group in the University of Bristol’s School of Biological Sciences built mathematical models of the placebo effect which examine the trade-off between the costs and benefits of an immune response when faced with a health problem.
The work is based on an idea proposed by the theoretical psychologist Professor Nicholas Humphrey. He proposed that, as it can be beneficial to hold the immune system back from full operation due to uncertainties about the state of the world (such as the possibility of starvation), cues which indicate a change can therefore lead to an altered level of immune response.
The models take this argument even further and demonstrate that the placebo effect is modulated by the patient’s expectations. Previous studies measuring brain activity using functional magnetic resonance imaging (fMRI) provide experimental evidence which support the models, by showing correlations between the placebo effect and regions of the brain associated with expectation.
The models show why changes to the perceived cost of getting well, the value of being well or external environmental factors can induce the placebo effect.
Dr Pete Trimmer, lead author of the work, said: “The placebo effect comes down to expectations about when to take action. Waiting for a useless pill before taking action is not optimal. But the general responsiveness to cues is adaptive, so it is logical for evolved organisms to display the placebo effect.”
The models indicate that under stress it can be better for the immune system to work less effectively. However, the most important finding of the research is that the particular type of belief in the treatment can lead to positive or negative effects. The belief that a treatment will cure, without any need for the immune system to do anything, could have deleterious effects on the patient’s health.
Now that a theoretical approach has laid the foundations of understanding the placebo effect, future empirical work may provide insights as to how the placebo effect can be invoked and controlled in a clinical environment. The Bristol study clearly shows that the focus of future placebo studies should be shifted to the type of belief patients have about their treatment rather than just whether a treatment is helpful or harmful. A better understanding of the placebo effect may change the code of practice for health practitioners and save human lives.
Source: University of Bristol
The MIT and University of Pennsylvania team decided that mimicking animal behaviour in robotics was not enough — by mimicking the genetic materials that allow those behaviours, they could make a giant leap towards feasible biorobots. It is the first time skeletal muscle has ever been manipulated to react to light, with past studies focusing only on cardiac muscle cells.
"With bio-inspired designs, biology is a metaphor, and robotics is the tool to make it happen," said MIT engineering professor Harry Asada, who has co-authored a paper on the study, due to appear in the journal Lab on a Chip. “With bio-integrated designs, biology provides the materials, not just the metaphor. This is a new direction we’re pushing in biorobotics.”
On the surface, ants and the Internet don’t seem to have much in common. But two Stanford researchers have discovered that a species of harvester ants determine how many foragers to send out of the nest in much the same way that Internet protocols discover how much bandwidth is available for the transfer of data. The researchers are calling it the “anternet.”
Columbia University Medical Center (CUMC) researchers have identified a potential medical treatment for the cognitive effects of stress-related disorders, including post-traumatic stress disorder (PTSD). The study, conducted in a PTSD mouse model, shows that an experimental drug called S107, one of a new class of small-molecule compounds called Rycals, prevented learning and memory deficits associated with stress-related disorders. The findings were published in the online edition of Cell.
Based on his earlier work in heart and muscle disorders, Dr. Marks reasoned that chronic stress could lead to PTSD by destabilizing type 2 ryanodine receptors (RyR2) in the hippocampus, the brain region that plays a central role in learning and memory. RyR2 are channels that regulate the level of calcium in neurons, which is vital to cell survival and function.
“When we examined the hippocampal neurons of the stressed mice, we found that their RyR2 channels had become destabilized and leaky compared with channels from normal non-stressed mice which were not leaky. There was a remodeling of the channels that we had previously seen in heart and skeletal muscles from animal models of chronic diseases including heart failure and muscular dystrophy. We found these same leaky channels in samples from patients with these disorders but not in those from healthy humans,” said Dr. Marks.
Studying Everyday Eye Movements Could Aid in Diagnosis of Neurological Disorders
USC-led team has designed a low-cost, easily-deployed method for detecting ADHD, Parkinson’s, and Fetal Alcohol Spectrum Disorder
Researchers at the University of Southern California have devised a method for detecting certain neurological disorders through the study of eye movements.
In a study published today in the Journal of Neurology, researchers claim that because Attention Deficit Hyperactivity Disorder (ADHD), Fetal Alcohol Spectrum Disorder (FASD) and Parkinson’s Disease (PD) each involve ocular control and attention dysfunctions, they can be easily identified through an evaluation of how patients move their eyes while they watch television.
“Natural attention and eye movement behavior – like a drop of saliva – contains a biometric signature of an individual and her/his state of brain function or dysfunction,” the article states. “Such individual signatures, and especially potential biomarkers of particular neurological disorders which they may contain, however, have not yet been successfully decoded.”
Typical methods of detection—clinical evaluation, structured behavioral tasks and neuroimaging—are costly, labor-intensive and limited by a patient’s ability to understand and comply with instructions. To solve this problem, doctoral student Po-He Tseng and Professor Laurent Itti of the Department of Computer Science at the USC Viterbi School of Engineering, along with collaborators at Queen’s University in Canada, have devised a new screening method.
Participants in the study were simply instructed to “watch and enjoy” television clips for 20 minutes while their eye movements were recorded. Eye-tracking data was then combined with normative eye-tracking data and a computational model of visual attention to extract 224 quantitative features, allowing the team to use new machine learning techniques to identify critical features that differentiated patients from control subjects.
With eye movement data from 108 subjects, the team was able to identify older adults with Parkinson’s Disease with 89.6% accuracy, and children with either ADHD or FASD with 77.3% accuracy.
Providing new insights into which aspects of attention and gaze control are affected by specific disorders, the team’s method provides considerable promise as an easily-deployed, low-cost, high-throughput screening tool, especially for young children and elderly populations who may be less compliant to traditional tests.
“For the first time, we can actually decode a person’s neurological state from their everyday behavior, without having to subject them to difficult or time-consuming tests,” Itti said.