Neuroscience

Month

August 2014

Aug 15, 201498 notes
#frontotemporal dementia #ALS #Lou Gehrig’s disease #neurodegeneration #neuroscience #science
Aug 15, 2014108 notes
#thalamic reticular nucleus #thalamus #sleep spindles #optogenetics #brain activity #neuroscience #science
Aug 15, 2014151 notes
#motor learning #motor control #memory #neuroscience #science
Awake within a dream: lucid dreamers show greater insight in waking life

People who are aware they are asleep when they are dreaming have better than average problem-solving abilities, new research has discovered.

image

Experts from the University of Lincoln, UK, say that those who experience ‘lucid dreaming’ – a phenomena where someone who is asleep can recognise that they are dreaming – can solve problems in the waking world better than those who remain unaware of the dream until they wake up.

The concept of lucid dreaming was explored in the 2010 film Inception, where the dreamers were able to spot incongruities within their dream. It is thought some people are able to do this because of a higher level of insight, meaning their brains detect they are in a dream because events would not make sense otherwise. This cognitive ability translates to the waking world when it comes to finding the solution to a problem by spotting hidden connections or inconsistencies, researchers say.

The research was carried out by Dr Patrick Bourke, Senior Lecturer at the Lincoln School of Psychology and his student Hannah Shaw. It is the first empirical study demonstrating the relationship between lucid dreaming and insight.

He said: “It is believed that for dreamers to become lucid while asleep, they must see past the overwhelming reality of their dream state, and recognise that they are dreaming.

“The same cognitive ability was found to be demonstrated while awake by a person’s ability to think in a different way when it comes to solving problems.”

The study examined 68 participants aged between 18 and 25 who had experienced different levels of lucid dreaming, from never to several times a month. They were asked to solve 30 problems designed to test insight. Each problem consisted of three words and a solution word.

Each of the three words could be combined with the solution word to create a new compound word.

For example with the words ‘sand’, ‘mile’ and ‘age’, the linking word would be ‘stone’.

Results showed that frequent lucid dreamers solved 25 per cent more of the insight problems than the non-lucid dreamers.

Miss Shaw, who conducted the research as part of her undergraduate dissertation, said the ability to experience lucid dreams is something that can be learned. “We aren’t entirely sure why some people are naturally better at lucid dreaming than others, although it is a skill which can be taught,” said Hannah.

“For example you can get into the habit of asking yourself “is this a dream?”. If you do this during the day when you are awake and make it a habit then it can transfer to when you are in a dream.”

Aug 14, 2014563 notes
#lucid dreaming #problem solving #cognition #psychology #neuroscience #science
Passengers who survived terrifying Air Transat flight in 2001, help psychologists uncover new clues about post-traumatic stress vulnerability

An extraordinary opportunity to study memory and post-traumatic stress disorder (PTSD) in a group of Air Transat passengers who experienced 30 minutes of unimaginable terror over the Atlantic Ocean in 2001 has resulted in the discovery of a potential risk factor that may help predict who is most vulnerable to PTSD.

image

The study, led by researchers at Baycrest Health Sciences, is published online this week in the journal Clinical Psychological Science – ahead of print publication. It is the first to involve detailed interviews and psychological testing in individuals exposed to the same life-threatening traumatic event. By necessity, other trauma studies involve heterogeneous events as experienced in different situations.

This opportunity was enhanced by the fact that one of the researchers, Dr. Margaret McKinnon, was a passenger on the plane. Heading off on her honeymoon in late August 2001, Dr. McKinnon’s flight departed Toronto for Lisbon, Portugal with 306 passengers and crew on board. Mid way over the Atlantic Ocean, the plane suddenly ran out of fuel. Everyone onboard was instructed to prepare for an ocean ditching, which included a countdown to impact, loss of on-board lighting and cabin de-pressurization. About 25 minutes into the emergency, the pilot located a small island military base in the Azores and glided the aircraft to a rough landing with no loss of life and few injuries.

“Imagine your worst nightmare – that’s what it was like,” said Dr. McKinnon, who initiated the study as a postdoctoral fellow at Baycrest’s Rotman Research Institute. She is now a clinician-scientist at St. Joseph’s Healthcare Hamilton and Associate Co-Chair of Research in the Department of Psychiatry and Behavioural Neurosciences at McMaster University in Hamilton.

“This wasn’t just a close call where your life flashes before your eyes in a split second and then everything is okay,” she said. The sickening feeling of “I’m going to die” lasted an excruciating 30 minutes as the plane’s systems shut down.

Following this incident, Dr. McKinnon and her colleagues at Baycrest – including Dr. Daniela Palombo (now a postdoctoral researcher at VA Boston Healthcare System and Boston University School of Medicine) and Dr. Brian Levine (senior scientist at Baycrest’s Rotman Research Institute and the University of Toronto) – recruited 15 passengers to participate in the Baycrest study. Using their knowledge of the moment-to-moment unfolding of events in this disaster, the researchers were able to probe both the quality and accuracy of passengers’ memories for the AT emergency in great detail along with two other events (Sept. 11, 2001 and a neutral event from the same time period) – and relate their findings to the presence or absence of PTSD in those passengers.

Not all passengers on Flight 236 went on to develop PTSD despite experiencing the same “single blow” traumatic event with the threat of imminent death.

The study produced two key findings. First, the Flight 236 passengers showed tremendously enhanced vivid memories of the plane emergency. Although the Baycrest team was not surprised by this, other research has suggested that memory for traumatic events is impoverished. Second, neither the vividness nor accuracy of memory related to who developed PTSD, but those with PTSD recalled a higher number of details external to the main event (i.e. details that were not specific in time, or were repetitions or editorial statements) compared to passengers who did not have PTSD and to healthy controls. This pattern was observed across all events tested, not just the traumatic event, suggesting that it is not just memory for the trauma itself that is related to PTSD, but rather how a person processes memory for events in general.

“What our findings show is that it is not what happened but to whom it happened that may determine subsequent onset of PTSD,” said Dr. Levine, senior author of the study.

This inability to shut out external or semantic details when recalling personally-experienced memories is related to mental control over memory recall, adding to a growing body of evidence that altered memory processing may be a vulnerability factor for PTSD.

A second study, in preparation for publication, involves functional brain imaging of 10 of the passengers from Air Transat Flight 236. The aim is to illuminate the brain mechanisms associated with exposure to this traumatic event.

Aug 14, 2014155 notes
#PTSD #memory #memory processing #psychology #neuroscience #science
Aug 14, 2014180 notes
#brain cancer #tumor cells #glioblastoma #nanoparticles #nanotechnology #neuroscience #science
Aug 14, 2014118 notes
#glioblastoma #brain tumors #aPKC #macrophages #neuroscience #science
Autism rates steady for two decades

A University of Queensland study has found no evidence of an increase in autism in the past 20 years, countering reports that the rates of autism spectrum disorders (ASDs) are on the rise.

image

The study, led by Dr Amanda Baxter from UQ’s Queensland Centre for Mental Health Research at the School of Population Health, was a first-of-its-kind analysis of research data from 1990 to 2010. 

Dr Baxter said she and her colleagues found that rates had remained steady, despite reports that the prevalence of ASDs was increasing.

“We found that the prevalence of ASDs in 2010 was one in 132 people, which represents no change from 1990,” Dr Baxter said.

“We found that better recognition of the disorders and improved diagnostic criteria explain much of the difference in study findings over time.”

Part of the Global Burden of Disease project, this is the largest study to systematically assess rates and disability caused by ASDs in the community, using data collected from global research findings in the past 20 years.

ASDs are chronic, disabling disorders that stem from problems with brain development.

They affect people from a young age and are among the world’s 20 most disabling childhood conditions.

The study shows that about 52 million children and adults around the globe meet diagnostic criteria for an ASD.

Dr Baxter said researchers hoped the study would help guide health policy and improve support for those with ASD and their families.

“As ASDs cause substantial lifelong health issues, an accurate understanding of the burden of these disorders can inform public health policy as well as help allocate necessary resources for education, housing and employment,” she said.

The study, a collaboration with the University of Leicester and the University of Washington’s Institute for Health Metrics and Evaluation, is published in Psychological Medicine journal.

Aug 14, 2014179 notes
#autism #ASD #neurodevelopmental disorders #health #burden of disease #psychology #neuroscience #science
Reduction of tau protein improves symptoms in model of severe childhood epilepsy

Researchers at the Gladstone Institutes have shown that reducing brain levels of the protein tau effectively blocks the development of disease in a mouse model of Dravet syndrome, a severe intractable form of childhood epilepsy. This therapeutic strategy not only suppressed seizure activity and premature death, but also improved cognitive and behavioral abnormalities that can accompany this syndrome.

Previous studies from this group have shown that lowering tau levels reduces abnormal brain activity in models of Alzheimer’s disease, but this is the first demonstration that tau reduction may also be beneficial in intractable genetic epilepsy.

"It would really be wonderful if tau reduction turned out to be useful not only in Alzheimer’s disease, but also in other disabling neurological conditions for which there currently are no effective treatments," said senior author Lennart Mucke, MD, the director of the Gladstone Institute of Neurological Disease and a professor of Neurology and Neuroscience at the University of California, San Francisco. "We suspected that this approach might be beneficial in Dravet, but we couldn’t be sure because of the severity of this syndrome and the corresponding model. We are thrilled that our strategy was so effective, but a lot more work is needed to advance it into the clinic."

Dravet syndrome is one of the most challenging forms of childhood epilepsy, resulting from a specific genetic mutation that affects sodium channels in the brain. Frequent, relentless seizures are accompanied by cognitive impairments and behavioral problems similar to autism, and up to 20% of patients succumb to sudden death. Current treatments for Dravet syndrome are largely ineffective, making research into the disorder particularly urgent.

"I am especially excited about the improvements we observed in cognitive and behavioral dysfunctions because these abnormalities are particularly hard on the kids—and their parents," said first author Ania Gheyara, MD, PhD, a staff scientist at Gladstone who is also affiliated with the UCSF Department of Pathology. "Our hope is that this approach will be broadly applicable to many different types of epilepsy."

In the study, which was published online today in the Annals of Neurology, the scientists reduced the level of the protein tau by genetically engineering Dravet mouse models, “knocking out” the gene associated with tau production. The deletion of one copy of the gene resulted in substantial improvements in most symptoms, while deleting both copies eliminated them almost completely. This included a significant reduction in both spontaneous and heat-induced seizures. The latter were used to mimic the fever-related seizures that are often seen in the early stages of Dravet syndrome. Network activity in the brain was also normalized, providing additional support for the remarkable ability of tau reduction to suppress epileptic activity.

Additionally, tau reduction ameliorated the learning and memory deficits and behavioral abnormalities present in the Dravet mice, which may relate to the cognitive impairments and autism-like behaviors seen in the human condition.

"The next steps are to develop tau-lowering therapeutics that could be used in humans and to evaluate their safety and efficacy in preclinical studies," said Dr. Mucke, "objectives we are pursuing actively."

Aug 14, 201464 notes
#epilepsy #dravet syndrome #tau protein #cognitive impairment #neuroscience #science
Aug 14, 2014559 notes
#science #mental illness #immune system #IL-6 #depression #inflammation #neuroscience
Aug 14, 201491 notes
#jet lag #lhx1 #circadian rhythms #suprachiasmatic nucleus #neuroscience #science
Aug 14, 2014286 notes
#mindfulness meditation #vajrayana meditation #EEG #relaxation #arousal #cognition #neuroscience #science
Aug 14, 2014106 notes
#3D imaging #microscopy #neuroscience #science
Hijacking the brain's blood supply: Tumor discovery could aid treatment

Dangerous brain tumors hijack the brain’s existing blood supply throughout their progression, by growing only within narrow potential spaces between and along the brain’s thousands of small blood vessels, new research shows for the first time.

image

(Caption: This microscopic view of a mouse brain tumor shows small clusters of tumor cells (in green), marked with white arrows, growing along tiny blood vessels (in red) in the brain and filling the space in between the vessels.)

The findings contradict the concept that brain tumors need to grow their own blood vessels to keep themselves growing – and help explain why drugs that aim to stop growth of the new blood vessels have failed in clinical trials to extend the lives of patients with the worst brain tumors.

In fact, trying to block the growth of new blood vessels in the brain actually spurs malignant tumors called gliomas to grow faster and further, the research shows. On the hopeful side, the research suggests a new avenue for finding better drugs.

The discoveries come from a University of Michigan Medical School team studying tumors in rodents and humans, and advanced computer models, in collaboration with colleagues from Arizona State University. Published online in the journal Neoplasia, they’ll be featured as the journal’s cover article later this month.

Read more

Aug 13, 201484 notes
#blood vessels #tumor cells #brain tumors #glioblastoma #medicine #neuroscience #science
Focal blood-brain-barrier disruption with high-frequency pulsed electric fields

A team of researchers from the Virginia Tech-Wake Forest University School of Biomedical Engineering and Sciences have developed a new way of using electricity to open the blood-brain-barrier (BBB). The Vascular Enabled Integrated Nanosecond pulse (VEIN pulse) procedure consists of inserting minimally invasive needle electrodes into the diseased tissue and applying multiple bursts of nanosecond pulses with alternating polarity. It is thought that the bursts disrupt tight junction proteins responsible for maintaining the integrity of the BBB without causing damage to the surrounding tissue. This technique is being developed for the treatment of brain cancer and neurological disorders, such as Parkinson’s disease, and is set to appear in the upcoming issue of the journal TECHNOLOGY.

image

(Caption: Two, minimally invasive needle electrodes with 1 mm active length were spaced 4.0 mm apart and inserted into the right cerebral hemisphere 1.5 mm beneath the surface of the dura. A burst of 200, 500 ns duration square pulses of alternating polarity with a voltage-to-distance ratio of 250 V/cm were applied through the electrodes. In the case shown above, bursts were repeated once per second for 10 min. The extent of BBB disruption is shown by the dotted line surrounding Evans blue-albumin complex uptake on the gross brain slice preparation (left) and the corresponding fluorescent image (middle). Additionally, areas of BBB disruption appear as hyperintense (white) on the T1-weighted MRI exam, due to the uptake of a gadolinium-Evans blue tracer. Scale bar represents 5 mm. Credit: John H. Rossmeisl Jr., Neurology and Neurosurgery, Virginia-Maryland Regional College of Veterinary Medicine and Virginia Tech-Wake Forest University School of Biomedical Engineering and Sciences).

The BBB is a network of tight junctions that normally acts to protect the brain from foreign substances by preventing them from leaking out of blood vessels. However, it also limits the effectiveness of drugs to treat brain disease. Temporarily opening the BBB is a way to ensure that drugs can still be effective.

For the treatment of brain cancer, “VEIN pulses could be applied at the same time as biopsy or through the same track as the biopsy probe in order to mitigate damage to the healthy tissue by limiting the number of needle insertions,” says Rafael V. Davalos, Ph.D, director of the Bioelectromechanical Systems Laboratory at Virginia Tech.

Additionally, the group shows that VEIN pulses can be applied without causing muscle contractions, which may dislodge the electrodes and require the use of a neuroblocker and general anesthesia. According to Christopher B. Arena, Ph.D., co-lead author on the paper with Paulo A. Garcia, Ph.D. and Michael B. Sano, Ph.D., “the fact that the pulses alternate in polarity helps to avoid unwanted, electrically induced movement. Therefore, it could be possible to perform this procedure without using a neuroblocker and with patients under conscious sedation. This is similar to how deep brain stimulation is implemented clinically to treat Parkinson’s disease.”

The team now plans to translate the technology into clinical applications through a university spin-out company, VoltMed, Inc.

Aug 13, 201470 notes
#blood-brain barrier #VEIN pulse #brain cancer #neurological disorders #neuroscience #science
Aug 13, 2014155 notes
#PTSD #glucocorticoids #corticosterone #stress #animal model #neuroscience #science
Aug 13, 201453 notes
#C. elegans #motor neurons #mRNA #splicing #genetics #neuroscience #science
Overhaul of our understanding of why autism potentially occurs

An analysis of autism research covering genetics, brain imaging, and cognition led by Laurent Mottron of the University of Montreal has overhauled our understanding of why autism potentially occurs, develops and results in a diversity of symptoms. The team of senior academics involved in the project calls it the “Trigger-Threshold-Target” model. Brain plasticity refers to the brain’s ability to respond and remodel itself, and this model is based on the idea that autism is a genetically induced plastic reaction. The trigger is multiple brain plasticity-enhancing genetic mutations that may or may not combine with a lowered genetic threshold for brain plasticity to produce either intellectual disability alone, autism, or autism without intellectual disability. The model confirms that the autistic brain develops with enhanced processing of certain types of information, which results in the brain searching for materials that possess the qualities it prefers and neglecting materials that don’t. “One of the consequences of our new model will be to focus early childhood intervention on developing the particular strengths of the child’s brain, rather than exclusively trying to correct missing behaviors, a practice that may be a waste of a once in a lifetime opportunity,” Mottron said.

image

Mottron and his colleagues developed the model by examining the effect of mutations involved in autism together with the brain activity of autistic people as they undertake perceptual tasks. “Geneticists, using animals implanted with the mutations involved in autism, have found that most of them enhance synaptic plasticity – the capacity of brain cells to create connections when new information is encountered. In parallel, our group and others have established that autism represents an altered balance between the processing of social and non-social information, i.e. the interest, performance and brain activity, in favor of non-social information,” Mottron explained. “The Trigger-Threshold-Target model builds a bridge between these two series of facts, using the neuro cognitive effects of sensory deprivation to resolve the missing link between them.”

The various superiorities that subgroups of autistic people present in perception or in language indicates that an autistic infant’s brain adapts to the information it is given in a strikingly similar way to sensory-deprived people. A blind infant’s brain compensate the lack of visual input by developing enhanced auditory processing abilities for example, and a deaf infant readapts to process visual inputs in a more refined fashion. Similarly, cognitive and brain imaging studies of autistic people work reveal enhanced activity, connectivity and structural modifications in the perceptive areas of the brain. Differences in the domain of information “targeted” by these plastic processes are associated with the particular pattern of strengths and weaknesses of each autistic individual. “Speech and social impairment in some autistic toddlers may not be the result of a primary brain dysfunction of the mechanisms related to these abilities, but the result of their early neglect,” Mottron said. “Our model suggests that the autistic superior perceptual processing compete with speech learning because neural resources are oriented towards the perceptual dimensions of language, neglecting its linguistic dimensions. Alternatively, for other subgroups of autistic people, known as Asperger, it’s speech that’s overdeveloped. In both cases, the overdeveloped function outcompetes social cognition for brain resources, resulting in a late development of social skills.”

The model provides insight into the presence or absence of intellectual disability, which when causative mutation alter the function of brain cell networking. Rather than simply triggering a normal but enhanced plastic reaction, these mutations cause neurons to connect in a way that does not exist in non-autistic people. When brain cell networking functions normally, only the allocation of brain resources is changed.

As is the case with all children, environment and stimulation have an effect on the development and organization of an autistic child’s brain. “Most early intervention programs adopt a restorative approach by working on aspects like social interest. However this focus may monopolize resources in favor of material that the child process with more difficulties, Mottron said. “We believe that early intervention for autistic children should take inspiration from the experience of congenitally deaf children, whose early exposure to sign language has a hugely positive effect on their language abilities. Interventions should therefore focus on identifying and harnessing the autistic child’s strengths, like written language.” By indicating that autistic ‘’restricted interests” result from cerebral plasticity, this model suggest that they have an adaptive value and should therefore be the focus of intervention strategies for autism.

Aug 13, 2014139 notes
#autism #gene mutations #synaptic plasticity #brain activity #neuroscience #science
New Study Points to a Brain Region Key to Contextual Memories

Dartmouth researchers demonstrate in a new study that a previously understudied part of the brain, the retrosplenial cortex, is essential for forming the basis for contextual memories, which help you to recall events ranging from global disasters to where you parked your car.

An important aspect of memory is the ability to recall the physical place, or context, in which an event occurred. For example, in recalling emotionally charged events such as the September 11 terror attacks or the assassination of President John F. Kennedy, we remember not only the event but also where we were when it happened. Indeed, in discussing such events with others, we often ask, “Where were you when … ?” Processing “where” information is also important for mundane events such as remembering where you parked your car.

Although it is known that a specific network of brain regions is important for contextual memory, it has not been known how different parts of the network contribute to this process. But using a newly developed technology known as “chemogenetics,” Professor David Bucci’s laboratory is beginning to show how different brain structures contribute to contextual learning and memory. Developed at the University of North Carolina School of Medicine, the chemogenetics technique enables researchers to “remotely control” the activity of brains cells. This is accomplished by using a virus to transfers genes for a synthetic receptor into a brain region. The receptors are responsive only to a synthetic drug that is administered through a simple injection. By binding to the receptors, the drug temporarily turns off—or on—brain cells in that region for a short amount of time.

Using this approach, Bucci’s laboratory demonstrated in an experiment with rats that the retrosplenial cortex is critical for forming the basis for contextual memories. It was the first time the chemogenetics technique had been used to turn off cells along the entire retrosplenial cortex. The importance of this finding is underscored by two recent studies showing that the hippocampus, another key brain region involved in contextual memories, is not itself active or necessary for forming the initial associations that underlie contextual memory.

The National Science Foundation recently awarded Bucci a five-year, $725,000 grant to continue this research.

“By providing new insight into the function of this part of the brain, our work will also have implications for understanding the basis for illnesses that impact contextual memory, such as Alzheimer’s disease,” Bucci says. “In fact, recent studies have shown that the retrosplenial cortex is one of the first brain areas that is damaged in persons with Alzheimer’s disease.”

The findings appear in The Journal of Neuroscience.

Aug 13, 201483 notes
#retrosplenial cortex #contextual memory #memory #brain cells #chemogenetics #neuroscience #science
Aug 13, 2014375 notes
#science #hippocampus #memory #memory reconsolidation #PTSD #drug addiction #neuroscience
Aug 13, 201493 notes
#huntington’s disease #huntingtin #aplysia #memory formation #synaptic plasticity #neuroscience #science
Aug 13, 2014414 notes
#science #brain tissue #white matter #gray matter #brain function #homeostasis #neurons #neuroscience
Target Identified For Rare Inherited Neurological Disease In Menhealth.ucsd.edu

ucsdhealthsciences:

Scientists show bad androgen receptor impairs body’s ability to dispose of damaged cells

Researchers at University of California, San Diego School of Medicine have identified the mechanism by which a rare, inherited neurodegenerative disease causes often crippling muscle weakness in men, in addition to reduced fertility.

The study, published August 10 in the journal Nature Neuroscience, shows that a gene mutation long recognized as a key to the development of Kennedy’s disease impairs the body’s ability to degrade, remove and recycle clumps of “trash” proteins that may otherwise build up on neurons, progressively impairing their ability to control muscle contraction. This mechanism, called autophagy, is akin to a garbage disposal system and is the only way for the body to purge itself of non-working, misshapen trash proteins.

“We’ve known since the mid-1990s that Alzheimer’s disease, Parkinson’s disease and Huntington’s disease are caused by the accumulation of misfolded proteins that should have been degraded, but cannot be turned over,” said senior author Albert La Spada, MD, PhD and professor of pediatrics, cellular and molecular medicine, and neurosciences. “The value of this study is that it identifies a target for halting the progression of protein build-up, not just in this rare disease, but in many other diseases that are associated with impaired autophagy pathway function.”

Of the 400 to 500 men in the U.S. with Kennedy’s disease, the slow but progressive loss of motor function results in about 15 to 20 percent of those with the disease becoming wheel-chair bound during later stages of the disease.

Kennedy’s disease, also known as spinal and bulbar muscular atrophy, is a recessive X-linked disease men inherit from their mother. Women don’t get the disease because they have two copies of the X chromosome. The genetic abnormality causes men to produce a mutant androgen receptor protein, which impairs the body’s sensitivity and response to male sex hormones, sometimes resulting in testicular atrophy and enlargement of male breasts.

In experiments with mice, scientists discovered that the mutant androgen receptor protein besides disrupting male reproductive biology also deactivates a protein called transcription factor EB (TFEB) that is believed to be a master regulator of autophagy in nerve and other cell types.

Specifically, the mutant androgen receptor protein in Kennedy’s disease binds to TFEB and blocks its ability to mediate the break-down and removal of non-working proteins and aggregated proteins.

“Our study tells us that if we can find a way to keep TFEB working, we likely can prevent this disease and others like it from progressing,” La Spada said. “We now have a target for new therapies to treat not only Kennedy’s disease, but also many more common neurological disorders.”

Aug 12, 201483 notes
Testosterone in Healthy Men Increases Their Brains’ Response to Threat

Testosterone, a steroid hormone, is well known to contribute to aggressive behavior in males, but the neural circuits through which testosterone exerts these effects have not been clear.

Prior studies found that the administration of a single dose of testosterone influenced brain circuit function. Surprisingly, however, these studies were conducted exclusively in women.

Researchers, led by Dr. Justin Carré, sought to rectify this gap by conducting a study of the effects of testosterone on the brain’s response to threat cues in healthy men.

They focused their attention on brain structures that mediate threat processing and aggressive behavior, including the amygdala, hypothalamus, and periaqueductal gray.

The researchers recruited 16 healthy young male volunteers, who completed two test days on which they received either testosterone or placebo. On both testing days, the men first received a drug that suppressed their testosterone. This step ensured that testosterone levels were similar among all study participants. The amount of testosterone administered in this study only returned testosterone levels to the normal range. Subjects then completed a face-matching task while undergoing a functional magnetic resonance imaging scan.

Data analyses revealed that, compared with placebo, testosterone increased reactivity of the amygdala, hypothalamus and periaqueductal grey when viewing angry facial expressions.

"We were able to show for the first time that increasing levels of testosterone within the normal physiological range can have a profound effect on brain circuits that are involved in threat-processing and human aggression," said Carré, Assistant Professor at Nipissing University.

"Understanding testosterone effects on the brain activity patterns associated with threat and aggression may help us to better understand the ‘fight or flight’ response in males that may be relevant to aggression and anxiety," commented Dr. John Krystal, Editor of Biological Psychiatry.

Expanding our knowledge of exactly how testosterone affects the male brain is particularly important, as testosterone augmentation has become increasingly promoted and aggressively marketed as a solution to reduced virility in aging men. Further work is indeed continuing, Carré said. “Our current work is examining the extent to which a single administration of testosterone influences aggressive and competitive behavior in men.”

Aug 12, 2014117 notes
#testosterone #brain activity #aggression #amygdala #androgens #emotion #neuroscience #science
Aug 12, 2014188 notes
Study captures brain activity in children suffering emergence delirium

In a world-first, a newly published study has captured in detail the brain electrical activity in children as they emerge from anaesthesia, shedding light on why some are distressed and agitated when they wake up.

image

Researchers from Swinburne University of Technology together with colleagues from the Murdoch Childrens Research Institute (MCRI) were able to collect electroencephalography (EEG) data on children who exhibited emergence delirium.

Emergence delirium is a major risk associated with anaesthesia in children and occurs when patients wake up from anaesthesia in a delirious and disassociated state.

Swinburne Professor David Liley said PhD student Jessica Martin and staff at MCRI were able to record, with unprecedented fidelity, brain electrical activity from 60 children aged 5-15 years who emerged from anaesthesia some of whom went on to exhibit emergence delirium.

“This clinical phenomenon is prevalent in children aged six and under, with an estimated 10-30% exhibiting emergence delirium,” said Professor Liley.

Researchers found that the brain activity recorded just after stopping sevoflurane (a form of gas anaesthesia) in children exhibiting emergence delirium was substantially different to those children who woke up peacefully. 

Associate Professor Andrew Davidson from MCRI said they discovered that children who wake up suddenly from a deeper plane of anaesthetic are more likely to develop the delirium.

“In contrast, the children who develop sleep like patterns on their EEG before they wake up are more likely to wake up peacefully.”

“Intriguingly, emergence delirium looks very much like the more severe form of night terror, which occurs when some pre-school children are disturbed during deep sleep.

“Our study suggests the EEG signatures and the mechanisms may indeed be similar between night terror and emergence delirium.

“Allowing children to wake up in a quiet and undisturbed environment should increase the likelihood that they go into a light sleep-like state after the anaesthetic and then wake up peacefully,” said Associate Professor Davidson.

The findings will have significant implications in both predicting those children who will go on to develop emergence delirium, as well as helping medical professionals better understand its causes in both children and adults.

The study, Alterations in the Functional Connectivity of Frontal Lobe Networks Preceding Emergence Delirium in Children, will appear in the October issue of the high profile clinical journal, Anesthesiology and is electronically available ahead of print. 

Aug 12, 2014186 notes
#science #brain activity #anesthesia #emergence delirium #children #functional connectivity #neuroscience
Aug 12, 2014104 notes
#glut1 deficiency #epileptic seizures #triheptanoin #cerebral metabolism #glucose #neuroscience #science
Aug 12, 2014460 notes
#science #STM #visual cortex #brain activity #visual memory #working memory #neuroscience
Aug 11, 201469 notes
#vitamin d #MS #newborns #immune system #pregnancy #neuroscience #science
People understand hyperbole through intent of communication

People tend to understand nonliteral language – metaphor, hyperbole and exaggerated statements – when they realize the purpose of the communication, according to new Stanford research.

Noah Goodman, an assistant professor of psychology at Stanford, believes that figurative language – the nuanced ways that people use language to communicate meanings different than the literal meaning of their words – is one of the deepest mysteries of human communication.

"Human communication," he said, "is rife with nonliteral language that includes metaphor, irony and hyperbole. When we say ‘Juliet is the sun’ or ‘That watch cost a million dollars,’ listeners read through the direct meanings – which are often false if taken literally – to understand subtle connotations."

image

'Sharp' vs. 'round' numbers

To understand this communication dynamic, Goodman, director of the Computation and Cognition Lab at Stanford, and his colleagues used computational modeling. Stanford graduate student Justine Kao was the first author on the paper, which included co-authors Jean Wu, a former graduate student at Stanford, and Leon Bergen of the Massachusetts Institute of Technology.

In their lab, they develop computational models that use pragmatic reasoning to interpret metaphorical utterances. Their research for this particular project involved four online experiments with 340 subjects.

Participants in the experiments read different scenarios involving hyperbole. For example, a person bought a watch and was asked by a friend whether it was expensive. That person responded with different figures, ranging from low- to high-cost figures – such as $50, $51, $10,000 or $10,001. Given this, the participants rated the probability of the purchaser thinking it was an expensive watch or not.

People tended to interpret “sharp numbers” – such as a watch costing $51 – more precisely than “round numbers,” as in a watch costing $50. 

The findings suggest that even creative and figurative language may follow predictable and rational principles.

Kao said, “This research advances our understanding of communication by providing evidence that reasoning about a speaker’s goals is critical for understanding nonliteral language. We were able to capture nuanced and nonliteral interpretations of number words using a computational model.”

Common ground

The research showed that if listeners are trying to understand the topic and goal of communication as well as the underlying subtext – that which is not expressed explicitly – they’re better able to truly understand the utterance. A sense of common knowledge about what is being described or expressed is also important. Speakers and listeners assume that individuals are rational agents who use common ground and reference points to best maximize information.

As Kao put it, “There is still a long way to go before computers can understand Shakespeare, but it is a start.”

Goodman offered this example: Imagine someone describing a new restaurant, and she says, “It took 30 minutes to get a table.” People are most likely to interpret this to mean she waited about 30 minutes. But if she says, “It took a million years to get a table,” people will probably interpret this to mean that the wait was shorter than a million years, but that the person thinks it was much too long.

"One of the most fascinating facts about communication is that people do not always mean what they say – a crucial part of the listener’s job is to understand an utterance even when its literal meaning is false," the researchers wrote.

Goodman said the computational model he and his colleagues use to understand nonliteral utterances integrates empirically measured background knowledge, communication principles and reasoning about communication goals.

What is next in line research-wise?

Goodman and the others said they believe that the same ideas and techniques can extend to metaphor, irony and many other uses of language. For example, they have a promising initial exploration of “is a” metaphors such as “your lawyer is a shark,” Goodman said.

"Beyond these cases of figurative speech, the overall mathematical framework is beginning to give a precise theory of natural language understanding that takes into account context, intention and many subtle shades of meaning," he said, adding, "There is a lot more work to do."

Aug 11, 2014152 notes
#communication #language #nonliteral language #hyperbole #pragmatics #psychology #neuroscience #science
Aug 11, 2014847 notes
#neurodegenerative diseases #neurological disorders #nanoelectronics #cyborg technology #neuroscience #science
'Seeing' through Virtual Touch Is Believing

A University of Cincinnati experiment aimed at this diverse and growing population could spark development of advanced tools to help all the aging baby boomers, injured veterans, diabetics and white-cane-wielding pedestrians navigate the blurred edges of everyday life.

These tools could be based on a device called the Enactive Torch, which looks like a combination between a TV remote and Captain Kirk’s weapon of choice. But it can do much greater things than change channels or stun aliens.

image

Luis Favela, a graduate student in philosophy and psychology, has found the torch enables the visually impaired to judge their ability to comfortably pass through narrow passages, like an open door or busy sidewalk, as good as if they were actually seeing such pathways themselves.

The handheld torch uses infra-red sensors to “see” objects in front of it. When the torch detects an object, it emits a vibration – similar to a cellphone alert – through an attached wristband. The gentle buzz increases in intensity as the torch nears the object, letting the user make judgments about where to move based on a virtual touch.

"Results of this experiment point in the direction of different kinds of tools or sensory augmentation devices that could help people who have visual impairment or other sorts of perceptual deficiencies. This could start a research program that could help people like that," Favela says.

Favela presented his research “Augmenting the Sensory Judgment Abilities of the Visually Impaired” at the American Psychological Association’s (APA) annual convention, held Aug. 7-10 in Washington, D.C. More than 11,000 psychology professionals, scholars and students from around the world annually attend APA’s convention.

A Growing Population in Need

Favela studies how people perceive their environment and how those perceptions inform their judgments. For this experiment, he was inspired by what he knew about the surging population of visually impaired Americans.

image

The Centers for Disease Control and Prevention (CDC) predicts that more than 6 million Americans age 40 and older will be affected by blindness or low vision by 2030 – double the number from 2004 – due to diabetes or other chronic diseases and the rapidly aging population. The CDC also notes that vision loss is among the top 10 causes of disability in the U.S., and vision impairment is one of the most prevalent disabilities in children.

"In my research I’ve found that there’s an emotional stigma that people who are visually impaired experience, particularly children," Favela says. "When you’re a kid in elementary school, you want to blend in and be part of the group. It’s hard to do that when you’re carrying this big, white cane."

Substituting Sight with Touch

In Favela’s experiment, 27 undergraduate students with normal or corrected-to-normal vision and no prior experience with mobility assistance devices were asked to make perceptual judgments about their ability to pass through an opening a few feet in front of them without needing to shift their normal posture. Favela tested participants’ judgments in three ways: using only their vision, using a cane while blindfolded and using the Enactive Torch while blindfolded. The idea was to compare judgments made with vision against those made by touch.

image

The results of the experiment were surprising. Favela figured vision-based judgments would be the most accurate because vision tends to be most people’s dominant perceptual modality. However, he found the three types of judgments were equally accurate.

"When you compare the participants’ judgments with vision, cane and Enactive Torch, there was not a significant difference, meaning that they made the same judgments," Favela says. "The three modalities are functionally equivalent. People can carry out actions just about to the same degree whether they’re using their vision or their sense of touch. I was really surprised."

Favela plans additional experiments requiring more complicated judgments, such as the ability to step over an obstacle or to climb stairs. With further study and improvements to the Enactive Torch, Favela says similar tools that augment touch-based perception could have a significant impact on the lives of the visually impaired.

"If the future version of the Enactive Torch is smaller and more compact, kids who use it wouldn’t stand out from the crowd, they might feel like they blend in more," he says, noting people can quickly adapt to using the torch. "That bodes well, say, for someone in the Marines who was injured by a roadside bomb. They could be devastated. But hope’s not lost. They will learn how to navigate the world pretty quickly."

Aug 11, 2014146 notes
#enactive torch #visual impairment #augmented reality #perception #sense of touch #psychology #neuroscience #science
Aug 10, 2014544 notes
#pain #pain management #virtual reality #technology #psychology #neuroscience #science
Aug 10, 2014332 notes
#brain activity #brain imaging #fluorescence imaging #nanotubes #neuroscience #science
Aug 10, 20141,861 notes
#science #tech #cognitive computing #brain chips #neurosynaptic chip #neurons #synapses #neuroscience
Aug 9, 201498 notes
#omega-3 #lipids #endocytosis #neurons #cell membrane #neuroscience #science
Aug 9, 2014260 notes
#musical training #music #learning #brain function #harmony project #psychology #neuroscience #science
Aug 9, 2014377 notes
#habits #automatic processes #prefrontal cortex #attitudes #health #psychology #neuroscience #science
Aug 9, 2014158 notes
#stem cells #stroke #CD34+ #brain tissue #medicine #neuroscience #science
Aug 9, 2014153 notes
#serotonin #neurons #serotonergic system #optogenetics #brain mapping #mental illness #neuroscience #science
Aug 9, 2014307 notes
#netrin-1 #brain cells #axons #DCC #UNC5 #x-ray crystallography #neuroscience #science
Ten-year study highlights sleep deficiency and sleep medication use in astronauts

In an extensive study of sleep monitoring and sleeping pill use in astronauts, researchers from Brigham and Women’s Hospital (BWH) Division of Sleep and Circadian Disorders, Harvard Medical School, and the University of Colorado found that astronauts suffer considerable sleep deficiency in the weeks leading up to and during space flight. The research also highlights widespread use of sleeping medication use among astronauts.

The study, published in The Lancet Neurology on August 8, 2014, recorded more than 4,000 nights of sleep on Earth, and more than 4,200 nights in space using data from 64 astronauts on 80 Shuttle missions and 21 astronauts aboard International Space Station (ISS) missions. The 10-year study is the largest study of sleep during space flight ever conducted. The study concludes that more effective countermeasures to promote sleep during space flight are needed in order to optimize human performance.

"Sleep deficiency is pervasive among crew members," stated Laura K. Barger, PhD, associate physiologist in the BWH Division of Sleep and Circadian Disorders, and lead study author. "It’s clear that more effective measures are needed to promote adequate sleep in crew members, both during training and space flight, as sleep deficiency has been associated with performance decrements in numerous laboratory and field-based studies."

Despite NASA scheduling 8.5 hours of sleep per night for crew members in space flight, the average (mean) duration of sleep during space flight was just under six (5.96) hours on shuttle missions, and just over six hours (6.09) on ISS missions. Twelve percent of sleep episodes on shuttle missions and 24 percent on ISS missions lasted seven hours or more, as compared to 42 percent and 50 percent, respectively, in a post-flight data collection interval when most astronauts slept at home.

Moreover, the results suggest that astronauts’ build-up of sleep deficiency began long before launch, as they averaged less than 6.5 hours sleep per night during the training interval occurring approximately three months prior to space flight.

The research also highlights widespread use of sleeping medications such as zolpidem and zaleplon during space flight. Three-quarters of ISS crew members reported taking sleep medication at some point during their time on the space station, and more than three-quarters (78 percent) of shuttle-mission crew members used medication on more than half (52 percent) of nights in space.

"The ability for a crew member to optimally perform if awakened from sleep by an emergency alarm may be jeopardized by the use of sleep-promoting pharmaceuticals," said Barger. "Routine use of such medications by crew members operating spacecraft are of particular concern, given the U. S. Federal Drug Administration (FDA) warning that patients using sleeping pills should be cautioned against engaging in hazardous occupations requiring complete mental alertness or motor coordination, including potential impairment of performance of such activities that may occur the day following ingestion of sedative/hypnotics. This consideration is especially important because all crew members on a given mission may be under the influence of a sleep promoting medication at the same time."

Charles Czeisler, PhD, MD, FRCP, chief, BWH Division of Sleep and Circadian Disorders, and senior study author, adds: “Future exploration spaceflight missions to the moon, Mars or beyond will require development of more effective countermeasures to promote sleep during spaceflight in order to optimize human performance. These measures may include scheduling modifications, strategically timed exposure to specific wavelengths of light, and behavioral strategies to ensure adequate sleep, which is essential for maintaining health, performance and safety.”

Aug 8, 201489 notes
#sleep deprivation #sleep meds #astronauts #human performance #neuroscience #science
Part of the brain stays "youthful" into older age

At least one part of the human brain may be able to process information the same way in older age as it does in the prime of life, according to new research conducted at the University of Adelaide.

image

A study compared the ability of 60 older and younger people to respond to visual and non-visual stimuli in order to measure their “spatial attention” skills.

Spatial attention is critical for many aspects of life, from driving, to walking, to picking up and using objects.

"Our studies have found that older and younger adults perform in a similar way on a range of visual and non-visual tasks that measure spatial attention," says Dr Joanna Brooks, who conducted the study as a Visiting Research Fellow with the University of Adelaide’s School of Psychology and the School of Medicine.

"Both younger (aged 18-38 years) and older (55-95 years) adults had the same responses for spatial attention tasks involving touch, sight or sound.

"In one task, participants were asked to feel wooden objects whilst blindfolded and decide where the middle of the object was - participants’ judgements were significantly biased towards the left-hand side of the true object centre. This bias is subtle but highly consistent," Dr Brooks says.

"When we think of ageing, we think not just of the physical aspects but also the cognitive side of it, especially when it comes to issues such as reaction time, which is typically slower among older adults. However, our research suggests that certain types of cognitive systems in the right cerebral hemisphere - like spatial attention - are ‘encapsulated’ and may be protected from ageing," she says.

Dr Brooks, who is now a Research Fellow in Healthy Ageing based at the Australian National University, recently presented her results at the 12th International Cognitive Neuroscience Conference in Brisbane. Her project is part of an international collaboration with scientists at the University of Edinburgh and Queen Margaret University in Scotland to better understand spatial attention in the human brain.

"Our results challenge current models of cognitive ageing because they show that the right side of the brain remains dominant for spatial processing throughout the entire adult lifespan," Dr Brooks says. "We now need to better understand how and why some areas of the brain seem to be more affected by ageing than others."

Dr Brooks’s research could also be helpful in better understanding how diseases such as Alzheimer’s affect the brain.

Aug 8, 2014159 notes
#spatial attention #aging #psychology #neuroscience #science
Aug 8, 2014157 notes
#neck manipulation #stroke #cervical artery dissection #neuroscience #science
Notch Developmental Pathway Regulates Fear Memory Formation

Nature is thrifty. The same signals that embryonic cells use to decide whether to become nerves, skin or bone come into play again when adult animals are learning whether to become afraid.

Researchers at Yerkes National Primate Research Center, Emory University, have learned that the molecule Notch, critical in many processes during embryonic development, is also involved in fear memory formation. Understanding fear memory formation is critical to developing more effective treatments and preventions for anxiety disorders such as post-traumatic stress disorder (PTSD). The results are scheduled for publication online this week by the journal Neuron.

"We are finding that developmental pathways that appear to be quiescent during adulthood are transiently reactivated to allow new memory formation to occur," says Kerry Ressler, MD, PhD, professor of psychiatry and behavioral sciences at Emory University School of Medicine and Yerkes National Primate Research Center, and senior author of the paper.

The first author of the paper is postdoctoral fellow Brian Dias, PhD, and co-authors include undergraduates Jared Goodman, Ranbir Ahluwalia and Audrey Easton, and post-doctoral researcher Raul Andero, PhD.

The Notch signaling pathway, present in insects, worms and vertebrates, is involved in embryonic patterning as well as nervous system and cardiovascular development. It’s a way for cells to communicate and coordinate which cells are going to become what types of tissues.

Dias and Ressler probed the Notch pathway because they were examining many genes that are activated in the brains of mice after they learn to become afraid of a sound paired with a mild foot-shock. They were looking for changes in the amygdala, a region of the brain known to regulate fear learning.

The researchers were particularly interested in micro RNAs. MicroRNAs do not encode proteins but can inhibit other genes, often several at once in a coordinated way. Dias and Ressler found that levels of miRNA-34a are increased in the amygdala after fear learning occurs. A day after fear training, animals whose brains were injected with a virus engineered to carry a “sponge” against miRNA-34a froze less often than control animals.

The researchers found that miRNA-34a regulated several genes that encode components of the Notch pathway. They believe their study is the first to link miRNA-34a and Notch signaling to a role in memory consolidation.

Notch is under investigation as a target in the treatment of various cancers and some drugs that target Notch have been well-tolerated by humans.

"From a therapeutic perspective, our data suggest that relevant drugs that regulate Notch signaling could potentially be a starting point for preventing or treating PTSD," Dias says.

Aug 8, 201478 notes
#PTSD #memory formation #memory consolidation #fear #amygdala #miRNA-34a #neuroscience #science
Aug 8, 2014231 notes
Aug 8, 2014541 notes
#science #BCI #prosthetics #prosthetic arm #motor movement #EEG #neuroscience
Aug 8, 2014120 notes
#creutzfeldt-jakob disease #prion disease #cerebrospinal fluid #olfaction #neuroscience #science
Older adults have morning brains! Study shows noticeable differences in brain function across the day

Older adults who are tested at their optimal time of day (the morning), not only perform better on demanding cognitive tasks but also activate the same brain networks responsible for paying attention and suppressing distraction as younger adults, according to Canadian researchers.

image

The study, published online July 7th in the journal Psychology and Aging (ahead of print publication), has yielded some of the strongest evidence yet that there are noticeable differences in brain function across the day for older adults.

“Time of day really does matter when testing older adults. This age group is more focused and better able to ignore distraction in the morning than in the afternoon,” said lead author John Anderson, a PhD candidate with the Rotman Research Institute at Baycrest Health Sciences and University of Toronto, Department of Psychology.

“Their improved cognitive performance in the morning correlated with greater activation of the brain’s attentional control regions – the rostral prefrontal and superior parietal cortex – similar to that of younger adults.” 

Asked how his team’s findings may be useful to older adults in their daily activities, Anderson recommended that older adults try to schedule their most mentally-challenging tasks for the morning time. Those tasks could include doing taxes, taking a test (such as a driver’s license renewal), seeing a doctor about a new condition, or cooking an unfamiliar recipe.

In the study, 16 younger adults (aged 19 – 30) and 16 older adults (aged 60-82) participated in a series of memory tests during the afternoon from 1 – 5 p.m. The tests involved studying and recalling a series of picture and word combinations flashed on a computer screen. Irrelevant words linked to certain pictures and irrelevant pictures linked to certain words also flashed on the screen as a distraction. During the testing, participants’ brains were scanned with fMRI which allows researchers to detect with great precision which areas of the brain are activated. Older adults were 10 percent more likely to pay attention to the distracting information than younger adults who were able to successfully focus and block this information. The fMRI data confirmed that older adults showed substantially less engagement of the attentional control areas of the brain compared to younger adults. Indeed, older adults tested in the afternoon were “idling” – showing activations in the default mode (a set of regions that come online primarily when a person is resting or thinking about nothing in particular) indicating that perhaps they were having great difficulty focusing. When a person is fully engaged with focusing, resting state activations are suppressed.

When 18 older adults were morning tested (8:30 a.m. – 10:30 a.m.) they performed noticeably better, according to two separate behavioural measures of inhibitory control. They attended to fewer distracting items than their peers tested at off-peak times of day, closing the age difference gap in performance with younger adults. Importantly, older adults tested in the morning activated the same brain areas young adults did to successfully ignore the distracting information. This suggests that when older adults are tested is important for both how they perform and what brain activity one should expert to see.

“Our research is consistent with previous science reports showing that at a time of day that matches circadian arousal patterns, older adults are able to resist distraction,” said Dr. Lynn Hasher, senior author on the paper and a leading authority in attention and inhibitory functioning in younger and older adults.

The Baycrest findings offer a cautionary flag to those who study cognitive function in older adults. “Since older adults tend to be morning-type people, ignoring time of day when testing them on some tasks may create an inaccurate picture of age differences in brain function,” said Dr. Hasher, senior scientist at Baycrest’s Rotman Research Institute and Professor of Psychology at University of Toronto.

Aug 7, 2014140 notes
#aging #cognitive performance #prefrontal cortex #parietal cortex #brain activity #brain function #psychology #neuroscience #science
Aug 7, 2014112 notes
#galectin-1 #brain tumours #glioma #cancer cells #t cells #immune system #neuroscience #science
Next page →
20132014
  • January
  • February
  • March
  • April
  • May
  • June
  • July
  • August
  • September
  • October
  • November
  • December
201220132014
  • January
  • February
  • March
  • April
  • May
  • June
  • July
  • August
  • September
  • October
  • November
  • December
20122013
  • January
  • February
  • March
  • April
  • May
  • June
  • July
  • August
  • September
  • October
  • November
  • December