Posts tagged brain activity
Articles and news from the latest research reports.
Early Intervention Improves Social Skills and Brain Activity in Preschoolers with Autism
The Early Start Denver Model (ESDM), a comprehensive behavioral early intervention program that is appropriate for children with autism spectrum disorder (ASD) as young as 12 months, has been found to be effective in improving social skills and brain responses to social cues in a randomized controlled study published online today in the Journal of the American Academy of Child & Adolescent Psychiatry.
“So much of a toddler’s learning involves social interaction, and early intervention that promotes attention to people and social cues may pay dividends in promoting the normal development of the brain and behavior,” said Geraldine Dawson, Ph.D., Autism Speaks chief science officer and the study’s lead author. This is the first controlled study of an intensive early intervention that demonstrates both improvement of social skills and brain responses to social stimuli resulting from intensive early intervention. Given that the American Academy of Pediatrics recommends that all 18- and 24-month-old children be screened for autism, “it is vital that we have effective therapies available for young children as soon as they are diagnosed,” continued Dr. Dawson.
“This may be the first demonstration that a behavioral intervention for autism is associated with changes in brain function as well as positive changes in behavior,” said Thomas R. Insel, M.D., director of the National Institute of Mental Health. “By studying changes in the neural response to faces, Dawson and her colleagues have identified a new target and a potential biomarker that can guide treatment development.”
ESDM, which combines applied behavioral analysis (ABA) teaching methods with developmental ‘relationship-based’ approaches, was previously demonstrated to achieve significant gains in cognitive, language and daily living skills compared to children with ASD who received commonly available community interventions. On average, the preschoolers receiving ESDM for two years improved 17.5 standard score points compared to 7.0 points in the community intervention comparison group.
Challenging Parkinson’s Dogma: Dopamine may not be the only key player in this tragic neurodegenerative disease
Scientists may have discovered why the standard treatment for Parkinson’s disease is often effective for only a limited period of time. Their research could lead to a better understanding of many brain disorders, from drug addiction to depression, that share certain signaling molecules involved in modulating brain activity.
A team led by Bernardo Sabatini, Takeda Professor of Neurobiology at Harvard Medical School, used mouse models to study dopamine neurons in the striatum, a region of the brain involved in both movement and learning. In people, these neurons release dopamine, a neurotransmitter that allows us to walk, speak and even type on a keyboard. When those cells die, as they do in Parkinson’s patients, so does the ability to easily initiate movement. Current Parkinson’s drugs are precursors of dopamine that are then converted into dopamine by cells in the brain.
The flip side of dopamine dearth is dopamine hyperactivity. Heroin, cocaine and amphetamines rev up or mimic dopamine neurons, ultimately reinforcing the learned reward of drug-taking. Other conditions such as obsessive-compulsive disorder, Tourette syndrome and even schizophrenia may also be related to the misregulation of dopamine.
In the October 11 issue of Nature, Sabatini and co-authors Nicolas Tritsch and Jun Ding reported that midbrain dopamine neurons release not only dopamine but also another neurotransmitter called GABA, which lowers neuronal activity. The previously unsuspected presence of GABA could explain why restoring only dopamine could cause initial improvements in Parkinson’s patients to eventually wane. And if GABA is made by the same cells that produce other neurotransmitters, such as depression-linked serotonin, similar single-focus treatments could be less successful for the same reason.
“If what we found in the mouse applies to the human, then dopamine’s only half the story,” said Sabatini.
Why crying babies are so hard to ignore: Study suggests the sound of a baby crying activates primitive parts of the brain involved in fight-or-flight responses
Ever wondered why it is so difficult to ignore the sound of a crying baby when you are trapped aboard a train or aeroplane? Scientists have found that our brains are hard-wired to respond strongly to the sound, making us more attentive and priming our bodies to help whenever we hear it – even if we’re not the baby’s parents.
"The sound of a baby cry captures your attention in a way that few other sounds in the environment generally do," said Katie Young of the University of Oxford, who led the study looking at how the brain processes a baby’s cries.
She scanned the brains of 28 people while they listened to the sound of babies and adults crying and sounds of animal distress including cats meowing and dogs whining.
Using a very fast scanning technique, called magnetoencephalography, Young found an early burst of activity in the brain in response to the sound of a baby cry, followed by an intense reaction after about 100 milliseconds. The reaction to other sounds was not as intense. “This was primarily in two regions of the brain,” said Young. “One is the middle temporal gyrus, an area previously implicated in emotional processing and speech; the other area is the orbitofrontal cortex, an area well-known for its role in reward and emotion processing.”
Young and her colleague, Christine Parsons, presented their findings this week at the annual meeting of the Society for Neuroscience in New Orleans.
How the brain forms categories
Neurobiologists at the Research Institute of Molecular Pathology (IMP) in Vienna investigated how the brain is able to group external stimuli into stable categories. They found the answer in the discrete dynamics of neuronal circuits. The journal Neuron publishes the results in its current issue.
How do we manage to recognize a friend’s face, regardless of the light conditions, the person’s hairstyle or make-up? Why do we always hear the same words, whether they are spoken by a man or woman, in a loud or soft voice? It is due to the amazing skill of our brain to turn a wealth of sensory information into a number of defined categories and objects. The ability to create constants in a changing world feels natural and effortless to a human, but it is extremely difficult to train a computer to perform the task.
At the IMP in Vienna, neurobiologist Simon Rumpel and his post-doc Brice Bathellier have been able to show that certain properties of neuronal networks in the brain are responsible for the formation of categories. In experiments with mice, the researchers produced an array of sounds and monitored the activity of nerve cell-clusters in the auditory cortex. They found that groups of 50 to 100 neurons displayed only a limited number of different activity-patterns in response to the different sounds.
The scientists then selected two basis sounds that produced different response patterns and constructed linear mixtures from them. When the mixture ratio was varied continuously, the answer was not a continuous change in the activity patters of the nerve cells, but rather an abrupt transition. Such dynamic behavior is reminiscent of the behavior of artificial attractor-networks that have been suggested by computer scientists as a solution to the categorization problem.
The findings in the activity patters of neurons were backed up by behavioral experiments with mice. The animals were trained to discriminate between two sounds. They were then exposed to a third sound and their reaction was tracked. Whether the answer to the third tone was more like the reaction to the first or the second one, was used as an indicator of the similarity of perception. By looking at the activity patters in the auditory cortex, the scientists were able to predict the reaction of the mice.
The new findings that are published in the current issue of the journal Neuron, demonstrate that discrete network states provide a substrate for category formation in brain circuits. The authors suggest that the hierarchical structure of discrete representations might be essential for elaborate cognitive functions such as language processing.
(Source: alphagalileo.org)
A glance at the brain’s circuit diagram
The human brain accomplishes its remarkable feats through the interplay of an unimaginable number of neurons that are interconnected in complex networks. A team of scientists from the Max Planck Institute for Dynamics and Self-Organization, the University of Göttingen and the Bernstein Center for Computational Neuroscience Göttingen has now developed a method for decoding neural circuit diagrams. Using measurements of total neuronal activity, they can determine the probability that two neurons are connected with each other.
From the twitching whiskers of babes: Naptime behavior shapes the brain
The whiskers of newborn rats twitch as they sleep, and that could open the door to new understandings about the intimate connections between brain and body. The discovery reinforces the notion that such involuntary movements are a vital contributor to the development of sensorimotor systems, say researchers who report their findings along with video of those whisker twitches on October 18 in Current Biology, a Cell Press publication.
"We found that even whiskers twitch during sleep—and they do so in infant rats long before they move their whiskers in the coordinated fashion known as whisking," said Mark Blumberg of The University of Iowa. "This discovery opens up new avenues for investigating how we develop critical connections between the sensors in our body and the parts of the brain that interpret and organize sensory information."
Will Neuroscience Radically Transform the Legal System?
Although academic fields will often enjoy more than Andy Warhol’s famous 15 minutes of fame, they too are subject to today’s ever-hungry machinery of hype. Like people, bands, diets, and everything else, a field gets discovered, plucked from obscurity, thrown into the spotlight, and quickly replaced as it becomes yesterday’s news.
Neuroscience is now the popular plat de jour, or, perhaps better, the prefixde jour, and neurolaw is one of the main beneficiaries—and victims. Neuroscience will have important and even dramatic effects on our society and, as a result, on our laws. But not yet, and not as dramatically as some envision.
First, consider timing. Many of the most interesting neuroscience results come from functional magnetic resonance imaging (fMRI). This technique allows us to see what parts of the brain are working and when, and thus to begin to correlate subjective mental states with physical brain states. The use of fMRI on humans goes back about 15 years, and although about 5,000 peer-reviewed scientific articles involving fMRI will be published this year, we are still trying to figure out how it works—or doesn’t. The fMRI results showing apparently purposeful brain activity in dead salmon are a wonderfully funny example of some of the limits of this technology, and fMRI is one of the oldest of the “new” neuroscience technologies. Half of what neuroscience is teaching us about human brain function will be shown, in the next 20 years, to be wrong—and we will need each of those 20 years to figure out which half.
But, second, we need a sense of proportion. Neuroscience will provide tools that will change the law in some important ways, but those tools will be neither perfect nor used in isolation, and those changes are not likely to strike at the law’s roots.
Research discovers two opposite ways our brain voluntarily forgets unwanted memories
If only there were a way to forget that humiliating faux pas at last night’s dinner party. It turns out there’s not one, but two opposite ways in which the brain allows us to voluntarily forget unwanted memories, according to a study published by Cell Press October 17 in the journal Neuron. The findings may explain how individuals can cope with undesirable experiences and could lead to the development of treatments to improve disorders of memory control.
"This study is the first demonstration of two distinct mechanisms that cause such forgetting: one by shutting down the remembering system, and the other by facilitating the remembering system to occupy awareness with a substitute memory," says lead study author Roland Benoit of the MRC Cognition and Brain Sciences Unit at the University of Cambridge.
Previous studies have shown that individuals can voluntarily block memories from awareness. Although several neuroimaging studies have examined the brain systems involved in intentional forgetting, they have not revealed the cognitive tactics that people use or the precise neural underpinnings. Two possible ways to forget unwanted memories are to suppress them or to substitute them with more desirable memories, and these tactics could engage distinct neural pathways.
(Source: medicalxpress.com)
Scientists reveal brain circuitry involved in post-traumatic stress and related disorders
Post-traumatic stress disorder (PTSD) is a severe anxiety disorder that can develop after experience of a traumatic or terrifying event, such as those experienced in combat or from sexual aggression. Such events can overwhelm the individual’s ability to cope and lead to a long-lasting disorder. Symptoms include re-experiencing the original trauma through flashbacks or nightmares, often triggered by seemingly innocuous events. PTSD can harm an individual’s relationships, ability to work, to sleep, and other aspects of life.
The lifetime prevalence of PTSD among adult Americans is 8 percent. Neither drug nor behavioral treatments currently available are consistently effective in treating PTSD. Therefore, scientists are studying brain changes associated with PTSD and related cognitive disorders, looking for clues to help in the development of new treatments.
Today’s findings show that:
- A fast-acting antidepressant, ketamine, appears to aid the formation of new nerve connections in the brain, helping to extinguish fearful memories. The mouse study could possibly lead to new PTSD treatments (Neil Fournier, PhD, abstract 399.09).
- In a mouse model, when dopamine neurons in the brain’s reward system are turned on and off with a genetically engineered “light switch,” depressive symptoms also come and go. The research highlights the importance of this neural circuit as a potential target for new depression treatments (Dipesh Chaudhury, PhD, abstract 522.01).
- Brain images of adolescents taken before and after the 2011 Japanese earthquake reveal that pre-existing weakness in certain brain connections could be a risk factor for intensified anxiety and PTSD after a traumatic life experience (Atsushi Sekiguchi, MD, PhD, abstract 168.12).
- Rodent studies show that repeated violent, competitive encounters drive changes in brain activity that shapes the ongoing behavior of losers and winners in distinct ways, and can contribute to depression and/or anxiety (Tamara Franklin, PhD, abstract 399.10).
Other recent findings discussed show:
- How exposure to stress causes molecular changes that weaken the ability of the prefrontal cortex to regulate behavior, thought, and emotion, while strengthening more primitive brain circuits (Amy Arnsten, PhD, abstract 310).
Relapse or recovery? Neuroimaging predicts course of substance addiction treatment
An Indiana University study has provided preliminary evidence that by measuring brain activity through the use of neuroimaging, researchers can predict who is likely to have an easier time getting off drugs and alcohol, and who will need extra help.
"We can also see how brain activity changes as people recover from their addictions," said Joshua Brown, assistant professor in the Department of Psychological and Brain Sciences at Indiana University Bloomington, part of the College of Arts and Sciences.
The chronic occurrence of relapse underscores the need for improved methods of treatment and relapse prevention. One potential cause for relapse is deficient self-regulatory control over behavior and decision-making. Specifically this lack of self-regulatory ability in substance dependent individuals has been associated with dysfunction of a mesolimbic-frontal brain network. Reduced activity within this self-regulatory brain network has previously been implicated in relapse, but the specific relationship between this network, self-regulatory ability and recovery is yet to be determined.