Posts tagged psychology
Articles and news from the latest research reports.
Neuroscientists today can preserve small volumes (<1mm³) of animal brain tissue immediately after death with incredible precision — the features and structure of every synapse within these volumes is well-protected down to the nanometer scale, using an inexpensive, room-temperature process of chemical fixation and plastic embedding, or “plastination.” This image is an example of plastination and local circuit tracing, occurring in leading neuroscience labs around the world today. (Credit: Brain Preservation Foundation)
Chemical brain preservation: how to live ‘forever’ — a personal view
What the brain draws from: Art and neuroscience
The human brain is wired in such a way that we can make sense of lines, colors and patterns on a flat canvas. Artists throughout human history have figured out ways to create illusions such as depth and brightness that aren’t actually there but make works of art seem somehow more real.
And while individual tastes are varied and have cultural influences, the brain also seems to respond especially strongly to certain artistic conventions that mimic what we see in nature.
15 Studied Effects of Classical Music on Your Brain
Classical music, whether you love it or hate it, has been a powerful cultural force for centuries. While it no longer dominates the music scene, the argument for continued appreciation of the genre goes far beyond pure aural aesthetics. Classical music has been lauded for its ability to do everything from improve intelligence to reduce stress, and despite some exaggeration of its benefits, science shows us that it actually does have a marked effect on the brain in a number of positive ways.
With September being Classical Music Month, there’s no better time to learn a bit more about some of the many ways classical music affects the brain. Over the past few decades, there have been numerous studies on the brain’s reaction to classical music, and we’ve shared the most relevant, interesting, and surprising here, some of which may motivate you to become a classical aficionado yourself.
What is reality?
WHEN you woke up this morning, you found the world largely as you left it. You were still you; the room in which you awoke was the same one you went to sleep in. The outside world had not been rearranged. History was unchanged and the future remained unknowable. In other words, you woke up to reality. But what is reality? The more we probe it, the harder it becomes to comprehend. In the eight articles on this page we take a tour of our fundamental understanding of the world around us, starting with an attempt to define reality and ending with the idea that whatever reality is, it isn’t what it seems. Hold on to your hats.
Controlling Brains With a Flick of a Light Switch
Using the new science of optogenetics, scientists can activate or shut down neural pathways, altering behavior and heralding a true cure for psychiatric disease.
Stopped at a red light on his drive home from work, Karl Deisseroth contemplates one of his patients, a woman with depression so entrenched that she had been unresponsive to drugs and electroshock therapy for years. The red turns to green and Deisseroth accelerates, navigating roads and intersections with one part of his mind while another part considers a very different set of pathways that also can be regulated by a system of lights. In his lab at Stanford University’s Clark Center, Deisseroth is developing a remarkable way to switch brain cells off and on by exposing them to targeted green, yellow, or blue flashes. With that ability, he is learning how to regulate the flow of information in the brain.
Deisseroth’s technique, known broadly as optogenetics, could bring new hope to his most desperate patients. In a series of provocative experiments, he has already cured the symptoms of psychiatric disease in mice. Optogenetics also shows promise for defeating drug addiction. When Deisseroth exposed a set of test mice to cocaine and then flipped a switch, pulsing bright yellow light into their brains, the expected rush of euphoria—the prelude to addiction—was instantly blocked. Almost miraculously, they were immune to the cocaine high; the mice left the drug den as uninterested as if they had never been exposed.
Pill for healthy ageing ‘available within a generation’
Dame Linda Partridge, a geneticist at University College London, claimed drugs will soon be available which can lower the risk of diseases like cancer and dementia by tackling the root cause – age itself.
Rather than promising immortality, taking the drugs from middle age or earlier could dramatically shorten the period of illness and frailty that we typically experience before we die.
Speaking at the EMBO life sciences meeting in Nice, France this week Dame Linda said several existing drugs have already been shown to have unexpected and welcome side effects, such as aspirin which reduces the risk of cancer.
Other therapies will be produced that mimic the effects of a severely restricted diet, which animal studies suggest can protect against a host of age-related conditions including heart disease and diabetes, she said.
Speaking after her keynote lecture, she told The Daily Telegraph: “One obvious approach in trying to deal with the very rapidly increasing incidence of age related diseases is to tackle the underlying aging process itself, because it is the major risk factor.
Benzodiazepine use and risk of dementia: prospective population based study
Objective To evaluate the association between use of benzodiazepines and incident dementia.
Design Prospective, population based study.
Setting PAQUID study, France.
Participants 1063 men and women (mean age 78.2 years) who were free of dementia and did not start taking benzodiazepines until at least the third year of follow-up.
Main outcome measures Incident dementia, confirmed by a neurologist.
Results During a 15 year follow-up, 253 incident cases of dementia were confirmed. New use of benzodiazepines was associated with an increased risk of dementia (multivariable adjusted hazard ratio 1.60, 95% confidence interval 1.08 to 2.38). Sensitivity analysis considering the existence of depressive symptoms showed a similar association (hazard ratio 1.62, 1.08 to 2.43). A secondary analysis pooled cohorts of participants who started benzodiazepines during follow-up and evaluated the association with incident dementia. The pooled hazard ratio across the five cohorts of new benzodiazepine users was 1.46 (1.10 to 1.94). Results of a complementary nested case-control study showed that ever use of benzodiazepines was associated with an approximately 50% increase in the risk of dementia (adjusted odds ratio 1.55, 1.24 to 1.95) compared with never users. The results were similar in past users (odds ratio 1.56, 1.23 to 1.98) and recent users (1.48, 0.83 to 2.63) but reached significance only for past users.
Conclusions In this prospective population based study, new use of benzodiazepines was associated with increased risk of dementia. The result was robust in pooled analyses across cohorts of new users of benzodiazepines throughout the study and in a complementary case-control study. Considering the extent to which benzodiazepines are prescribed and the number of potential adverse effects of this drug class in the general population, indiscriminate widespread use should be cautioned against.
New Treatments May Help Restore Speech Lost to Aphasia
Most people know the frustration of having a word on the “tip of your tongue” that they simply can’t remember. But that passing nuisance can be an everyday occurrence for someone with aphasia, a communication disorder caused by a stroke or other brain damage that impairs the ability to process language.
About 1 million Americans — roughly one in every 250 — are affected by aphasia, which can also impact reading and writing skills. But how they acquire the problem and how long they’ll endure it differ from person to person, explained Ellayne Ganzfried, a speech-language pathologist and executive director of the National Aphasia Association.
"No two people with aphasia are alike because everyone’s brain responds to the injury in a different way," Ganzfried said. "About half of people who have aphasia recover quickly, within the first few days. If the symptoms of aphasia last longer than two or three months, a complete recovery is unlikely … [though] some people continue to improve over a period of years and even decades."
Strokes are the most common cause, followed by head injuries, tumors, migraines or other neurological issues. Depending on the damage to the brain regions controlling language, which are typically in the left hemisphere, the resulting aphasia can be broken into four broad categories:
- Difficulty expressing thoughts through speech or writing
- Difficulty understanding spoken or written language
- Difficulty using the correct names for objects, people, places or events
- Loss of almost all language function, with no ability to speak or understand speech.
"Processing language requires the collaboration of lots of different parts or systems of the brain," explained Karen Riedel, director of speech-language pathology at the Rusk Institute of Rehabilitation Medicine at NYU Langone Medical Center in New York City. "The whole brain ‘talks’ — the whole brain has something to do with the use of language."
Because of this, a variety of therapies are used to help people regain as much speech and language as possible. But regardless of the injury, people with aphasia have the best chances for recovery when language therapy begins immediately, Riedel said.
Because aphasia is so variable, a therapy that helps one person might not help another, she noted. Tried-and-true techniques include melodic intonation therapy, which uses melody and rhythm to help improve the ability to retrieve words, and constraint-induced therapy, which forces people to use speech over other communication methods.
But technology, Riedel said, has introduced new language-improvement techniques into the mix over the last few years that are both exciting and fun. Several apps available for iPhone or iPad involve synthetic speech that helps engage those with aphasia in yet another realm of communication.
"Our patients have much more access to different kinds of programs that are computer-based," she said. "There’s always something new around the corner."
What remains a constant concern, however, is the misunderstanding many people have of those with language difficulties and how to treat them, Ganzfried and Riedel agreed.
"Many people with aphasia will become socially isolated because of their communication difficulties, which can lead to depression," Ganzfried said. "There are also many misconceptions about aphasia, including that the person is mentally unstable or under the influence of drugs or alcohol. It’s also extremely frustrating. Imagine knowing what you want to say in your head but you can’t get the words out."
(Source: consumer.healthday.com)
Risk-Sensitivity in Bayesian Sensorimotor Integration
Information processing in the nervous system during sensorimotor tasks with inherent uncertainty has been shown to be consistent with Bayesian integration. Bayes optimal decision-makers are, however, risk-neutral in the sense that they weigh all possibilities based on prior expectation and sensory evidence when they choose the action with highest expected value. In contrast, risk-sensitive decision-makers are sensitive to model uncertainty and bias their decision-making processes when they do inference over unobserved variables. In particular, they allow deviations from their probabilistic model in cases where this model makes imprecise predictions. Here we test for risk-sensitivity in a sensorimotor integration task where subjects exhibit Bayesian information integration when they infer the position of a target from noisy sensory feedback. When introducing a cost associated with subjects’ response, we found that subjects exhibited a characteristic bias towards low cost responses when their uncertainty was high. This result is in accordance with risk-sensitive decision-making processes that allow for deviations from Bayes optimal decision-making in the face of uncertainty. Our results suggest that both Bayesian integration and risk-sensitivity are important factors to understand sensorimotor integration in a quantitative fashion.
When Your Eyes Tell Your Hands What to Think: You’re Far Less in Control of Your Brain Than You Think
You’ve probably never given much thought to the fact that picking up your cup of morning coffee presents your brain with a set of complex decisions. You need to decide how to aim your hand, grasp the handle and raise the cup to your mouth, all without spilling the contents on your lap.
A new Northwestern University study shows that, not only does your brain handle such complex decisions for you, it also hides information from you about how those decisions are made.
"Our study gives a salient example," said Yangqing ‘Lucie’ Xu, lead author of the study and a doctoral candidate in psychology at Northwestern. "When you pick up an object, your brain automatically decides how to control your muscles based on what your eyes provide about the object’s shape. When you pick up a mug by the handle with your right hand, you need to add a clockwise twist to your grip to compensate for the extra weight that you see on the left side of the mug.
"We showed that the use of this visual information is so powerful and automatic that we cannot turn it off. When people see an object weighted in one direction, they actually can’t help but ‘feel’ the weight in that direction, even when they know that we’re tricking them," Xu said.