Posts tagged neuroscience

Posts tagged neuroscience
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."
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 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.”
“Generating interesting connections between disparate subjects is what makes art so fascinating to create and to view … we are forced to contemplate a new, higher pattern that binds lower ones together.”
It seems to be the season for fascinating meditations on consciousness, exploring such questions as what happens while we sleep, how complex cognition evolved, and why the world exists. Joining them and prior explorations of what it means to be human is The Ravenous Brain: How the New Science of Consciousness Explains Our Insatiable Search for Meaning (public library) by Cambridge neuroscientist Daniel Bor in which, among other things, he sheds light on how our species’ penchant for pattern-recognition is essential to consciousness and our entire experience of life.
The process of combining more primitive pieces of information to create something more meaningful is a crucial aspect both of learning and of consciousness and is one of the defining features of human experience. Once we have reached adulthood, we have decades of intensive learning behind us, where the discovery of thousands of useful combinations of features, as well as combinations of combinations and so on, has collectively generated an amazingly rich, hierarchical model of the world. Inside us is also written a multitude of mini strategies about how to direct our attention in order to maximize further learning. We can allow our attention to roam anywhere around us and glean interesting new clues about any facet of our local environment, to compare and potentially add to our extensive internal model.
Scientists have claimed to have solved the mystery of why coffee never tastes as good as it smells.
Apparently, the act of swallowing the drink sends a burst of aroma up the back of the nose from inside the mouth, activating a “second sense of smell” in the brain that is less receptive to the flavour, causing a completely different and less satisfying sensation.
“We have got two senses of smell. One sense is when you inhale things from the environment into you, and the other is when the air comes out of you up the nasal passage and is breathed out through the nose,” the Telegraph quoted Prof Barry Smith, of the University of London, as saying at the British Science Festival in Aberdeen.
The phenomenon is down to the fact that, although we have sensors on our tongue, 80 percent of what we think of as taste actually reaches us through smell receptors in our nose, the paper said. The receptors, which relay messages to our brain, react to odours differently depending on which direction they are moving in, it added.
In the case of coffee, the taste is also hampered by the fact that 300 of the 631 chemicals that combine to form its complex aroma are wiped out by saliva, causing the flavour to change before we swallow it, Prof Smith added.
Supplementation with the omega-3 fatty acid DHA may help improve reading skills and behavior in kids who need help most — those whose test scores place them in the bottom 20% of their elementary school class — according to a new controlled trial.
Researchers at Oxford University’s Center for Evidence-Based Intervention studied 362 7- to 9-year-old children who had placed in the bottom third of their class in reading scores. For 16 weeks, the children were given either a placebo or 600 mg of DHA (docosahexaenoic acid). The DHA was extracted from algae, which are the original source of the omega-3 fatty acids found in fish.
Over the 16-week trial, the children receiving placebos progressed in their reading skills as expected. But those students who received DHA and had scored in the bottom 20% of readers at the start of the study advanced by nearly an extra month, while those in the bottom 10% gained nearly two extra months of progress. Students whose reading skills were less impaired — those whose scores had placed them at the highest end of the bottom third — did not see extra improvements with DHA.
Parents of the kids who received DHA also rated their children as more attentive and less restless, as compared with those who got placebo. However, teachers did not report improvement in the children’s behavior.
What good is color vision in the dark of the deep sea? For some crabs, an ability to see blue and ultraviolet light may mean the difference between chowing down on a good meal versus a toxic one.
A new study published in the Journal of Experimental Biology finds that some seafloor, or benthic, crabs can see in color. But the crustaceans live in darkness of the deep Caribbean where sunlight does not penetrate, making their sensitivity to blue and ultraviolet light mysterious.
(Source: livescience.com)
This month, in honor of National Women’s Health and Fitness Day on September 26th, we’ll be exploring upcoming and previously published work in PLOS ONE surrounding this topic. The breadth of this subject is wide and, sure, we could probably start a whole new blog just to discuss PLOS ONE articles about women’s health, but instead we’ve created a bite-sized series that will highlight a few important issues, including cardiovascular health, anorexia, pregnancy, and ovarian cancer.