Posts tagged brain
Articles and news from the latest research reports.
Doctors have long recognized a link between alcoholism and anxiety disorders such as post-traumatic stress disorder (PTSD). Those who drink heavily are at increased risk for traumatic events like car accidents and domestic violence, but that only partially explains the connection. New research using mice reveals heavy alcohol use actually rewires brain circuitry, making it harder for alcoholics to recover psychologically following a traumatic experience.
“There’s a whole spectrum to how people react to a traumatic event,” said study author Thomas Kash, PhD, assistant professor of pharmacology at the University of North Carolina School of Medicine. “It’s the recovery that we’re looking at — the ability to say ‘this is not dangerous anymore.’ Basically, our research shows that chronic exposure to alcohol can cause a deficit with regard to how our cognitive brain centers control our emotional brain centers.”
The study, which was published online on Sept. 2, 2012 by the journal Nature Neuroscience, was conducted by scientists at the National Institute on Alcohol Abuse and Alcoholism (NIAAA) and UNC’s Bowles Center for Alcohol Studies.
Flying High: Researchers Decipher Manic Gene
ScienceDaily (Sep. 1, 2012) — Flying high, or down in the dumps — individuals suffering from bipolar disorder alternate between depressive and manic episodes. Researchers from the University of Bonn and the Central Institute of Mental Health in Mannheim have now discovered, based on patient data and animal models, how the NCAN gene results in the manic symptoms of bipolar disorder.
(Credit: © Bastos / Fotolia)
The results have been published in the current issue of The American Journal of Psychiatry.
Individuals with bipolar disorder are on an emotional roller coaster. During depressive phases, they suffer from depression, diminished drive and often, also from suicidal thoughts. The manic episodes, however, are characterized by restlessness, euphoria, and delusions of grandeur. The genesis of this disease probably has both hereditary components as well as psychosocial environmental factors.
The NCAN gene plays a major part in how manias manifest
"It has been known that the NCAN gene plays an essential part in bipolar disorder," reports Prof. Dr. Markus M. Nöthen, Director of the Institute of Human Genetics at the University of Bonn. "But until now, the functional connection has not been clear." In a large-scale study, researchers led by the University of Bonn and the Central Institute of Mental Health in Mannheim have now shown how the NCAN gene contributes to the genesis of mania. To do so, they evaluated the genetic data and the related descriptions of symptoms from 1218 patients with differing ratios between the manic and depressive components of bipolar disorder.
Comprehensive data from patients and animal models
Using the patients’ detailed clinical data, the researchers tested statistically which of the symptoms are especially closely related to the NCAN gene. “Here it became obvious that the NCAN gene is very closely and quite specifically correlated with the manic symptoms,” says Prof. Dr. Marcella Rietschel from the Central Institute of Mental Health in Mannheim. According to the data the gene is, however, not responsible for the depressive episodes in bipolar disorder.
Manic mice drank from sugar solution with abandon
A team working with Prof. Dr. Andreas Zimmer, Director of the Institute of Molecular Psychiatry at the University of Bonn, examined the molecular causes effected by the NCAN gene. The researchers studied mice in which the gene had been “knocked out.” “It was shown that these animals had no depressive component in their behaviors, only manic ones,” says Prof. Zimmer. These knockout mice were, e.g., considerably more active than the control group and showed a higher level of risk-taking behavior. In addition, they tended to exhibit increased reward-seeking behavior, which manifested itself by their unrestrained drinking from a sugar solution offered by the researchers.
Lithium therapy also effective against hyperactivity in mice
Finally, the researchers gave the manic knockout mice lithium — a standard therapy for humans. “The lithium dosage completely stopped the animals’ hyperactive behavior,” reports Prof. Zimmer. So the results also matched for lithium; the responses of humans and mice regarding the NCAN gene were practically identical. It has been known from prior studies that knocking out the NCAN gene results in a developmental disorder in the brain due to the fact that the production of the neurocan protein is stopped. “As a consequence of this molecular defect, the individuals affected apparently develop manic symptoms later,” says Prof. Zimmer.
Opportunity for new therapies
Now the scientists want to perform further studies of the molecular connections of this disorder — also with a view towards new therapies. “We were quite surprised to see how closely the findings for mice and the patients correlated,” says Prof. Nöthen. “This level of significance is very rare.” With a view towards mania, the agreement between the findings opens up the opportunity to do further molecular studies on the mouse model, whose results will very likely also be applicable to humans. “This is a great prerequisite for advancing the development of new drugs for mania therapy,” believes Prof. Rietschel.
Source: Science Daily
When she was 9 years old, Camilla would entertain her friends by jumping off her bed and landing directly on her knees. She said she liked to hear the crunching sound they made—just like popcorn.
Another time, Camilla spent an entire school recess period walking around on a broken leg, without so much as a whimper, says neuroscientist India Morrison of the University of Gothenburg in Sweden. The child’s teachers didn’t believe Camilla when she said something was wrong, because she wasn’t sobbing or wailing in pain. Her father thought perhaps her leg needed massaging, but quickly realized the situation was much worse.
A CT scanner uses radiation to produce a three-dimensional image of the insides of the human body. X-rays are fired through the body, and scanners pick up the path of the rays, leading to a detailed image of the body. It can be used to detect and diagnose epilepsy, Alzheimer’s disease, cancers, heart disease and medical issue.
(Source: Daily Mail)
University of Tennessee Researchers Develop Comprehensive, Accessible Vision Testing Device
Eighty-five percent of children’s learning is related to vision. Yet in the United States, eighty percent of children have never had an eye exam or any vision screening before kindergarten, statistics say. When they do, the vision screenings they typically receive can detect only one or two conditions. Ying-Ling Chen, research assistant professor in physics at the University of Tennessee Space Institute in Tullahoma is working to change that with an invention that makes eye exams inexpensive, comprehensive, and simple to administer.
Languages are extremely diverse, but they are not arbitrary. Behind the bewildering, contradictory ways in which different tongues conceptualise the world, we can sometimes discern order. Linguists have traditionally assumed that this reflects the hardwired linguistic aptitude of the human brain. Yet recent scientific studies propose that language “universals” aren’t simply prescribed by genes but that they arise from the interaction between the biology of human perception and the bustle, exchange and negotiation of human culture.
Language has a logical job to do—to convey information—and yet it is riddled with irrationality: irregular verbs, random genders, silent vowels, ambiguous homophones. You’d think languages would evolve towards an optimal state of concision, but instead they accumulate quirks that hinder learning, not only for foreigners but also for native speakers.
These peculiarities have been explained by linguists by reference to the history of the people who speak it. That’s often fascinating, but it does not yield general principles about how languages have developed—or how they will change in future. As they evolve, what guides their form?
Amyotrophic lateral sclerosis, also known as Lou Gehrig’s disease or ALS, is a devastating, rapidly advancing disease of the nerve cells in the brain and spinal cord that control voluntary muscle movement. But researchers at NYU School of Medicine have identified a new target for slowing the deterioration of physical function for which the disease is so well known.
In their new study, published August 30, 2012 online ahead of print in Cell Reports, lead investigator Steven J. Burden, PhD, and colleagues show that, by increasing the signaling activity of a protein called muscle skeletal receptor tyrosine-protein kinase (MuSK), they were able to keep nerve cells attached to muscle longer into the progression of the disease in a mouse model of ALS.
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
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.