Posts tagged psychology
Articles and news from the latest research reports.
Specific Antibodies Halt Alzheimer’s Disease in Mice
ScienceDaily (Mar. 6, 2012) — Antibodies that block the process of synapse disintegration in Alzheimer’s disease have been identified, raising hopes for a treatment to combat early cognitive decline in the disease.
Amyloid beta (cyan blue) binds to nerve cells of the hippocampus (red) and attacks synapses resulting in the loss of memories in Alzheimer’s disease. New research has led to important insights into the mechanisms that induce synapse loss. The discovery brings hope for the development of new therapies that protect synapses and therefore prevent memory loss in Alzheimer’s disease. (Credit: Silvia Purro/Patricia Salinas/UCL)
Alzheimer’s disease is characterized by abnormal deposits in the brain of the protein Amyloid-ß, which induces the loss of connections between neurons, called synapses.
Now, scientists at UCL have discovered that specific antibodies that block the function of a related protein, called Dkk1, are able to completely suppress the toxic effect of Amyloid-ß on synapses. The findings are published March 6 in the Journal of Neuroscience.
Professor Patricia Salinas (UCL Department of Cell & Developmental Biology) who led the study, said: “These novel findings raise the possibility that targeting this secreted Dkk1 protein could offer an effective treatment to protect synapses against the toxic effect of Amyloid-ß.
"Importantly, these results raise the hope for a treatment and perhaps the prevention of cognitive decline early in Alzheimer’s disease."
Surgery soon after failure of drug treatment for epilepsy may lower risk of seizures
March 6, 2012
Patients with epilepsy who underwent brain surgery soon after failing to respond to drug treatment, but who also continued to receive drug therapy, had a lower risk of seizures during the 2nd year of follow-up compared to patients who received drug treatment alone, according to a study in the March 7 issue of JAMA.
"Epilepsy is a worldwide serious health concern, accounting for 1 percent of the global burden of disease, equivalent to lung cancer in men and breast cancer in women. The 20 percent to 40 percent of patients who have medically intractable epilepsy account for 80 percent of the cost of epilepsy. Temporal lobe epilepsy (TLE) is the most common cause of drug-resistant seizures, but it can be treated surgically," according to background information in the article. The American Academy of Neurology practice parameter recommends surgery as the treatment of choice for medically intractable TLE, but use of this treatment is delayed and underutilized. Patients who are referred for surgery have had epilepsy for an average of 22 years, more than 10 years after failure of 2 antiepileptic drugs (AEDs). Because earlier surgery could prevent significant illness and premature death, it has been recommended that a randomized controlled trial be conducted to evaluate its efficacy.
Jerome Engel Jr., M.D., Ph.D., of the University of California, Los Angeles, and colleagues conducted a study to compare outcomes of surgery for epilepsy with those of continued drug treatment. The clinical trial, performed at 16 U.S. epilepsy surgery centers, included 38 participants (18 men and 20 women; age 12 years or older) who had mesial temporal lobe (a section of the brain) epilepsy (MTLE) and disabling seizures for no more than 2 consecutive years following adequate trials of 2 brand-name AEDs. Planned enrollment was 200, but the trial was halted prematurely due to slow accrual. Eligibility for anteromesial temporal resection (AMTR; surgery/removal of tissue of a section of the brain) was based on a standardized presurgical evaluation protocol. Participants were randomized to continued AED treatment (n = 23) or a standardized AMTR plus AED treatment (n = 15). In the medical group, 7 participants underwent AMTR prior to the end of follow-up and 1 participant in the surgical group never received surgery. The primary outcome measure for the study was freedom from disabling seizures during year 2 of follow-up. Other outcomes included measures on health-related quality of life (QOL) and cognitive function.
New brain imaging and computer modeling predicts autistic brain activity and behavior
March 6, 2012
Schematic diagrams of a normal brain (left) and an autistic brain (right) highlight the white matter alterations in autism. Credit: Carnegie Mellon University
New research from Carnegie Mellon University’s Marcel Just provides an explanation for some of autism’s mysteries — from social and communication disorders to restricted interests — and gives scientists clear targets for developing intervention and treatment therapies.
Autism has long been a scientific enigma, mainly due to its diverse and seemingly unrelated symptoms until now.
Published in the journal Neuroscience and Biobehavioral Reviews, Just and his team used brain imaging and computer modeling to show how the brain’s white matter tracts — the cabling that connects separated brain areas — are altered in autism and how these alterations can affect brain function and behavior. The deficiencies affect the tracts’ bandwidth — the speed and rate at which information can travel along the pathways.
"White matter is the unsung hero of the human brain," said Just, the D.O. Hebb Professor of Psychology within CMU’s Dietrich College of Humanities and Social Sciences and director of the university’s Center for Cognitive Brain Imaging. "In autistic individuals, we can measure the quality of the white matter, and our computer model can predict how coordinated their brain activity will be. This gives us a precise account of the underlying alterations affecting autistic thought."
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Hypothermia protects the brain against damage during stroke
March 6, 2012
Thromboembolic stroke, caused by a blood clot in the brain, results in damage to the parts of the brain starved of oxygen. Breaking up the clot with tissue plasminogen activator (tPA) reduces the amount of damage, however, there is a very short time window when the value of the treatment outweighs the side effects. New research published in BioMed Central’s open access journal Experimental & Translational Stroke Medicine shows that, during the first 24 hours after a stroke, mild hypothermia (34C) can reduce the side effects of tPA and potentially increase the window of opportunity for tPA treatment.
When a blood clot blocks off blood flow in the brain (ischemic stroke) the part starved of oxygen quickly begins to die. In order to prevent significant damage tPA must be given to the patient as early as possible after the onset of symptoms - doctors recommend that it must be administered within the first four and a half hours. Delayed treatment also increases the patient’s risk of intracerebral hemorrhage and brain swelling (edema).
Mild hyperthermia is known to be neuroprotective and to reduce damage caused by the return of blood flow to an area of the brain starved of oxygen by a clot. Researchers from the University of Erlangen, led by Dr Rainer Kollmar, tested whether mild hyperthermia could also prevent damage to the brain due to tPA treatment in rats. After 24 hours they found that, while hypothermia reduced the amount of swelling and damaged tissue in the brain after a stroke, tPA (administered 90 minutes after the onset of stroke) increased it. However, they also discovered that hypothermia therapy was able to offset the damage due to tPA.
This seemed to be true for all the measurements they looked at. Dr Kollmar explained, “Patients often loose brain function such as control over parts of their body, speech or memory after stroke. We looked at ‘neuroscore’, to examine how much control of the body had been affected, and at markers for inflammation (TIMP-1 and sICAM) or evidence of damage to the blood brain barrier. In all cases hypothermia was able to offset the side effects of tPA.”
While these results are still experimental, new techniques which prevent shivering mean that this technique is easier to administer in conscious patients. Preliminary clinical trials are also beginning to show that it is possible to treat patients, who have had a stroke, with tPA plus hypothermia. Our results suggest that hypothermia can offset the side effects of tPA and further studies will show if it is also able to increase the window of opportunity of tPA treatment in patients.
Provided by BioMed Central
Source: medicalxpress.com
Removing molecule speeds relief from depression
March 6, 2012
Getting rid of a protein increases the birth of new nerve cells and shortens the time it takes for antidepressants to take effect, according to an animal study in the March 7 issue of The Journal of Neuroscience. The protein, neurofibromin 1, normally helps prevent uncontrolled cell growth. The findings suggest therapeutic strategies aimed at stimulating new nerve cell birth may help treat depression better than current antidepressants that commonly take several weeks to reach full efficacy.
Throughout life, a section of the hippocampus — the brain’s learning and memory center — produces new nerve cells. This process, called neurogenesis, is made possible by specialized cells called neural progenitor cells (NPCs). While previous studies show adult neurogenesis declines with age and stress, therapies known to alleviate symptoms of depression, such as exercise and antidepressants, increase neurogenesis.
In the new study, a team of scientists directed by Luis Parada, PhD, of the University of Texas Southwestern, examined neurogenesis after deleting the neurofibromin 1 (Nf1) gene from NPCs in adult mice. Removal of Nf1 increased the number and maturation of newborn nerve cells in the adult hippocampus. Nf1 mutant mice showed reductions in depressive- and anxiety-like behaviors following 7 days of antidepressant treatment, whereas mice without the mutation took longer to show improvements.
"Our findings establish an important role for Nf1 in controlling neurogenesis in the hippocampus and demonstrate that activation of adult NPCs is enough to regulate depression- and anxiety-like behaviors," said study co-author Renee McKay, PhD, of the University of Texas Southwestern. "Our work is among the first to demonstrate the feasibility of altering mood via direct manipulation of adult neurogenesis," McKay added.
To determine if deleting Nf1 in adult NPCs leads to long-term behavioral changes in mice, the scientists ran 8-month-old mice through a battery of tests designed to measure anxiety- and depressive-like behaviors. Compared with other mice, the mutant mice showed less signs of anxiety and demonstrated resistance to the effects of chronic mild, unpredictable stress. The finding shows even without antidepressants, the deletion of Nf1 from NPCs in adult mice decreases symptoms of depression and anxiety.
"This study demonstrates that inducing neurogenesis is sufficient to produce antidepressant behavioral actions, and provides novel targets for therapeutic interventions," said Ronald Duman, PhD, a neurogenesis expert from Yale University.
Provided by Society for Neuroscience
Source: medicalxpress.com
New Alzheimer’s Marker Strongly Predicts Mental Decline
ScienceDaily (Mar. 5, 2012) — A new marker of Alzheimer’s disease can predict how rapidly a patient’s memory and other mental abilities will decline after the disorder is diagnosed, researchers at Washington University School of Medicine in St. Louis have found.
In 60 patients with early Alzheimer’s disease, higher levels of the marker, visinin-like protein 1 (VILIP-1), in the spinal fluid were linked to a more rapid mental decline in the years that followed.
Scientists need to confirm the results in larger studies, but the new data suggest that VILIP-1 potentially may be a better predictor of Alzheimer’s progression than other markers.
“VILIP-1 appears to be a strong indicator of ongoing injury to brain cells as a result of Alzheimer’s disease,” says lead author Rawan Tarawneh, MD, now an assistant professor of neurology at the University of Jordan. “That could be very useful in predicting the course of the disease and in evaluating new treatments in clinical trials.”
Scientists Search for Source of Creativity
It takes two to tango. Two hemispheres of your brain, that is.
USC researchers are working to pin down the exact source of creativity in the brain and have found that the left hemisphere of your brain, thought to be the logic and math portion, actually plays a critical role in creative thinking. “We want to know how does creativity work in the brain?” said Lisa Aziz-Zadeh, assistant professor of neuroscience at the USC Dornsife College of Letters, Arts and Sciences.
If you paint or sculpt, you may think of yourself as right-brained. The right hemisphere of your brain often is thought to be the creative half, while the left is thought to be the rational, logical side.
But a new study from a team led by Aziz-Zadeh demonstrated that while the right half of your brain performs the bulk of the heavy lifting when you’re being creative, it does call for help from the left half of your noggin.
The study, which focuses on how the brain tackles visual creative tasks, supports previous findings about how the brain handles musical improvisation.
Co-authored by USC graduate student Sook-Lei Liew and USC undergraduate Francesco Dandekar, the study was posted online last month in Social Cognitive and Affective Neuroscience.
“We need both hemispheres for creative processing,” Aziz-Zadeh said.
The USC scholar and her team used functional magnetic resonance imaging (fMRI) to scan the brains of architecture students, who tend to be visually creative.
While being scanned, the subjects were shown three shapes: a circle, a C and an 8. They then were asked to visualize images that could be made by rearranging those shapes – for example, a face (with the 8 on its side to become the eyes, the C on its side to become the smiling mouth and the circle in the center as the nose).
The students also were asked to simply try to piece three geometric shapes together with their minds and see if they formed a square or a rectangle – a task that requires similar spatial processing but not necessarily creativity.
Even though it mainly was handled by the right hemisphere, the creative task actually lit up the left hemisphere more than the noncreative task. The results indicated that the left brain potentially is a crucial supporter of creativity in the brain.
Aziz-Zadeh said she plans to explore more of how different types of creativity (painting, acting, singing) are created by the brain, what they have in common and what makes them different.
Source: Neuroscience News
Neuroscientist group finds daydreaming uses same parts of the brain as social skills
March 5, 2012 by Bob Yirka
(Medical Xpress) — A group of Australian neuroscientists have been reviewing the results of many studies done over the years regarding the parts of the brain that are thought to be used in different real world scenarios and have found that many of them appear to be involved when people go into what is called a default network - more commonly known as daydreaming, or running on auto-pilot. Their findings suggest, as they write in their paper published in Nature Reviews Neurology, that the default network is tied very closely with the same areas of the brain generally thought of as those used for social skills.
To find connections, the team looked at studies of elderly people that had fallen victim to two distinct forms of early onset dementia. One involved damage to the frontal lobe, the other to the temporal lobe. Damage to the frontal lobe, they point out, generally results in patients displaying an inability to understand why they should curb their language. They’re impulsive and aren’t able to understand the repercussions of their words or actions as they pertain to other people. Those with damage to the temporal lobe on the other hand, have trouble understanding the subtle cues that go on between people when interacting. They generally run into trouble in trying to read emotion in others and also tend to have difficulty remembering faces or other everyday objects. Both conditions obviously have a very direct and troublesome impact on social interaction.
They also found that when people without dementia are placed in an fMRI machine and who are allowed to daydream, various parts of their brain light up, indicating that the default network is quite complicated and involved. But of specific interest to this group of researchers was the fact that many of those areas that light up when transitioning to the default network, are the same ones that are used for social interaction, memory and imagination.
This means, they say, that the default network is more than just daydreaming because for it to occur, there needs to be memory of events that have transpired, imagination to guess about things that might happen in the future and the consequences of different happenings. Not coincidentally, they add, all these things are necessary for social interaction as well. This, they say, is why it’s time to stop looking at individual brain functions as separate events and instead to start looking at events as multi-brain activities that all together add up to the richness of thought we all experience as thinking human beings.
Source: medicalxpress.com
Researchers gain new insight into prefrontal cortex activity
March 5, 2012
The brain has a remarkable ability to learn new cognitive tasks while maintaining previously acquired knowledge about various functions necessary for everyday life. But exactly how new information is incorporated into brain systems that control cognitive functions has remained a mystery.
A study by researchers at Wake Forest Baptist Medical Center and the McGovern Institute of the Massachusetts Institute of Technology shows how new information is encoded in neurons of the prefrontal cortex, the area of the brain involved in planning, decision making, working memory and learning.
"In this study we were able to isolate activity directly from the brain, allowing us to ‘see’ what was happening in the prefrontal cortex before and after a new task was learned," said Christos Constantinidis, Ph.D., associate professor of neurobiology and anatomy at Wake Forest Baptist and senior author of the study, published in the March 5 online edition of Proceedings of the National Academy of Sciences.
To gain insight into how learning a new task affects the prefrontal cortex, the researchers analyzed the electrical activity of neurons before and after training for the performance in two short-term memory tests. Two monkeys initially looked at a computer screen while various shapes, such as squares and circles, were displayed, and researchers recorded the electrical activity occurring in the brain. The same animals were then trained to recognize the various shapes, and to remember whether two symbols matched each other.
Using computational analysis of the neuronal recordings, the researchers compared data to assess what information was present before training and what new information arose while learning a new task. They found that learning was associated with activation of a small number of neurons that were highly specialized for the new task, while the same neurons maintained the existing information that was present before training.
"In essence, this select group of neurons was able to multitask by learning new information while retaining information they were already specialized for," Constantinidis said. "Our results show that although there was little change in the amount of basic stimulus information that neurons encoded before training, more complex information about whether the symbols matched became incorporated throughout the prefrontal cortex after training."
Overall these findings shed light on how new information is incorporated into the prefrontal cortex activity and how neural activity codes information, which should lead to richer theories of how the prefrontal cortex controls behavior and how information is encoded in neural activity more generally.
"We hope that our findings will help others who work with patients who have short-term memory problems resulting from strokes or traumatic brain injuries," Constantinidis said. "Computerized training to perform cognitive tasks, like those used in our study, has shown promise in cognitive rehabilitation, and for treatment of mental illnesses and conditions, such as schizophrenia and ADHD."
Provided by Wake Forest Baptist Medical Center
Source: medicalxpress.com
Study suggest that conscious perception has little to do with the primary visual cortex
When the rings of dynamic patterns are presented to the same eye (left column), the subject is able to consciously perceive the target pattern-the stripes in the center of the ring. When the two are presented to different eyes (right column), the dynamic pattern suppresses perception of the target pattern. Under both conditions, participants were asked to perform a task that focused attention on the target (top row) or on letters presented outside the target area (bottom row). Credit: 2012 Masataka Watanabe
From a purely intuitive point of view, it is easy to believe that our ability to actively pay attention to a target is inextricably connected with our capacity to consciously perceive it. However, this proposition remains the subject of extensive debate in the research community, and surprising new findings from a team of scientists in Japan and Europe promise to fuel the debate.
Resolving how these aspects of perception are managed requires a detailed understanding of how the visual centers in our brain process information. A region known as V1 has been investigated as it represents the first portion of the visual cortex to receive and process signals transmitted from the retina.
Many researchers favor a model in which functions pertaining consciousness are widely spread among the whole visual system, including V1. The classical model, which assumes that the neural mechanism of consciousness is integrated into a narrow subset of brain structures, referred to as a homunculus, or ‘little human’, is almost defunct. However, a modern version of this model is under debate. It proposes that the neural mechanism of consciousness is a privileged set of cortical areas, a subpopulation of neurons, or certain neural dynamics (e.g. oscillations); while there are also visual systems that have nothing to do with conscious vision, explains Masataka Watanabe a researcher investigating brain function at the University of Tokyo, Japan.
Watanabe cites studies proposing that visual attention as processed within V1 may be only minimally impacted by conscious perception; but, the experimental data have been contradictory. For example, studies using a technique called functional magnetic resonance imaging (fMRI) to map brain activity have indicated that V1 contributes to both attention and awareness in humans. However, invasive electrophysiological studies in non-human primates yielded different results. “You would find only 10 to 15% of neurons in V1 that are barely modulated by awareness, and 85% or so that are not modulated at all,” says Watanabe. To resolve this ambiguity, he, Kang Cheng from the RIKEN Brain Science Institute, Wako, and their colleagues designed an experiment that examined both processes independently. Surprisingly, their results may lend support the modern homunculus model.