Why anesthetics cause prolonged memory loss
November 3, 2014
Science Daily/University of Toronto
Researchers have shown why anesthetics can cause long-term memory loss, a discovery that can have serious implications for post-operative patients.
Until now, scientists haven't understood why about a third of patients who undergo anesthesia and surgery experience some kind of cognitive impairment -- such as memory loss -- at hospital discharge. One-tenth of patients still suffer cognitive impairments three months later.
Anesthetics activate memory-loss receptors in the brain, ensuring that patients don't remember traumatic events during surgery. Professor Beverley Orser and her team found that the activity of memory loss receptors remains high long after the drugs have left the patient's system, sometimes for days on end.
Animal studies showed this chain reaction has long-term effects on the performance of memory-related tasks."Patients -- and even many doctors -- think anesthetics don't have long-term consequences. Our research shows that our fundamental assumption about how these drugs work is wrong," says Orser, a Professor in the Departments of Anesthesia and Physiology, and anesthesiologist at Sunnybrook Health Sciences Centre.
Science Daily/SOURCE :http://www.sciencedaily.com/releases/2014/11/141103192130.htm
Vitamin B may not reduce risk of memory loss after all
November 12, 2014
Science Daily/American Academy of Neurology (AAN)
Taking vitamin B12 and folic acid supplements may not reduce the risk of memory and thinking problems after all, according to a new study. The study is one of the largest to date to test long-term use of supplements and thinking and memory skills.
The study involved people with high blood levels of homocysteine, an amino acid. High levels of homocysteine have been linked to memory loss and Alzheimer's disease.
"Since homocysteine levels can be lowered with folic acid and vitamin B12 supplements, the hope has been that taking these vitamins could also reduce the risk of memory loss and Alzheimer's disease," said study author Rosalie Dhonukshe-Rutten, PhD, of Wageningen University in Wageningen, the Netherlands.
Early observational studies showed there may be some benefit to thinking and memory skills in taking folic acid and vitamin B12, but the results of later randomized, controlled trials were less convincing.
For the current study, 2,919 people with an average age of 74 took either a tablet with 400 μg of folic acid and 500 μg of vitamin B12 or a placebo every day for two years. Tests of memory and thinking skills were performed at the beginning and end of the study. All of the participants had high blood levels of homocysteine.
"While the homocysteine levels decreased by more in the group taking the B vitamins than in the group taking the placebo, unfortunately there was no difference between the two groups in the scores on the thinking and memory tests," said Dhonukshe-Rutten.
Science Daily/SOURCE :http://www.sciencedaily.com/releases/2014/11/141112161038.htm
Calorie-restricting diets slow aging
November 17, 2014
Science Daily/NYU Langone Medical Center
Neuroscientists have shown that calorie-reduced diets stop the normal rise and fall in activity levels of close to 900 different genes linked to aging and memory formation in the brain.
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While restrictive dietary regimens have been well-known for decades to prolong the lives of rodents and other mammals, their effects in humans have not been well understood. Benefits of these diets have been touted to include reduced risk of human heart disease, hypertension, and stroke, Ginsberg notes, but the widespread genetic impact on the memory and learning regions of aging brains has not before been shown. Previous studies, he notes, have only assessed the dietary impact on one or two genes at a time, but his analysis encompassed more than 10,000 genes.
For the study, female mice, which like people are more prone to dementia than males, were fed food pellets that had 30 percent fewer calories than those fed to other mice. Tissue analyses of the hippocampal region, an area of the brain affected earliest in Alzheimer's disease, were performed on mice in middle and late adulthood to assess any difference in gene expression over time
Science Daily/SOURCE :http://www.sciencedaily.com/releases/2014/11/141117110650.htm
Trans fat consumption linked to diminished memory in working-aged adults
November 18, 2014
Science Daily/American Heart Association
Trans fat consumption is adversely linked to memory sharpness in young to middle-aged men. Men under 45 years old who ate higher amounts of trans fats, which are found in processed foods, had significantly reduced ability to recall words. Further studies need to determine whether these effects extend to women under 45 years old.
"Trans fats were most strongly linked to worse memory, in young and middle-aged men, during their working and career-building years," said Beatrice A. Golomb, M.D., Ph.D., lead author and professor of medicine at the University of California-San Diego. "From a health standpoint, trans fat consumption has been linked to higher body weight, more aggression and heart disease. As I tell patients, while trans fats increase the shelf life of foods, they reduce the shelf life of people."
Golomb and her coauthor studied adults who had not been diagnosed with heart disease, including men age 20 or older and postmenopausal women. Participants completed a dietary questionnaire, from which the researchers estimated participants' trans fat consumption. To assess memory, researchers presented participants with a series of 104 cards showing words. Participants had to state whether each word was new or a word duplicated from a prior card.
They found:
Among men under age 45, those who ate more trans fats showed notably worse performance on the word memory test. The strength of the association remained even after taking into consideration things like age, education, ethnicity and depression.
Each additional gram a day of trans fats consumed was associated with an estimated 0.76 fewer words correctly recalled.
For those eating the highest amounts of trans fats, this translated to an estimated 11 fewer words (a more than 10 percent reduction in words remembered), compared to adults who ate the least trans fat. (The average number of words correctly recalled was 86.)
"Foods have different effects on oxidative stress and cell energy," Golomb said. In a previous study, we found chocolate, which is rich in antioxidants and positively impacts cell energy, is linked to better word memory in young to middle-aged adults. In this study, we looked at whether trans fats, which are prooxidant and linked adversely to cell energy, might show the opposite effect. And they did."
Science Daily/SOURCE :http://www.sciencedaily.com/releases/2014/11/141118105406.htm
Musicians show advantages in long-term memory
November 18, 2014
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Science Daily/University of Texas at Arlington
Psychologists have demonstrated a link between musical training and long-term memory advantages.
"Musically trained people are known to process linguistic materials a split second faster than those without training, and previous research also has shown musicians have advantages in working memory," said Park. "What we wanted to know is whether there are differences between pictorial and verbal tasks and whether any advantages extend to long-term memory. If proven, those advantages could represent an intervention option to explore for people with cognitive challenges."
The musicians, all of whom had been playing classical music for more than 15 years, outperformed non-musicians in EEG-measured neural responses on the working memory tasks. But, when long-term memory was tested, the enhanced sensitivity was only found in memory for pictures.
The study has not explored why the advantages might develop. Park said it's possible professional musicians become more adept at taking in and processing a host of pictorial cues as they navigate musical scores.
Park's abstract for the conference reports that musicians' neural responses in the mid-frontal part of the brain were 300 to 500 milliseconds faster than non musicians and responses in the parietal lobe were 400 to 800 milliseconds faster than non musicians. The parietal lobe is directly behind the frontal lobe of the brain and is important for perceptual processing, attention and memory.
"Dr. Park's research uses the latest scientific instrumentation to reveal knowledge about human cognition that was previously unreachable," said James Grover, interim dean of the UT Arlington College of Science. "It provides usable information about far-reaching advantages arts training can bring."
Science Daily/SOURCE :http://www.sciencedaily.com/releases/2014/11/141118125554.htm
Spice up your memory: Just one gram of turmeric a day could boost memory
November 18, 2014
Science Daily/Monash University
Adding just one gram of turmeric to breakfast could help improve the memory of people who are in the very early stages of diabetes and at risk of cognitive impairment.
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"We found that this modest addition to breakfast improved working memory over six hours in older people with pre-diabetes," Professor Wahlqvist said.
Turmeric is widely used in cooking, particularly in Asia. Its characteristic yellow colour is due to curcumin, which accounts for 3 to 6 per cent of turmeric and has been shown by experimental studies to reduce the risk of dementia.
"Our findings with turmeric are consistent with these observations, insofar as they appear to influence cognitive function where there is disordered energy metabolism and insulin resistance," Professor Wahlqvist said.
Science Daily/SOURCE :http://www.sciencedaily.com/releases/2014/11/141118110009.htm
Tooth loss linked to slowing mind, body
December 18, 2014
Science Daily/University College London
The memory and walking speeds of adults who have lost all of their teeth decline more rapidly than in those who still have some of their own teeth, finds new research.
The association between total tooth loss and memory was explained after the results of a study were fully adjusted for a wide range of factors, such as sociodemographic characteristics, existing health problems, physical health, health behaviors, such as smoking and drinking, depression, relevant biomarkers, and particularly socioeconomic status. However, after adjusting for all possible factors, people without teeth still walked slightly slower than those with teeth.
These links between older adults in England losing all natural teeth and having poorer memory and worse physical function 10 years later were more evident in adults aged 60 to 74 years than in those aged 75 and older.
"Tooth loss could be used as an early marker of mental and physical decline in older age, particularly among 60-74 year-olds," says lead author Dr Georgios Tsakos (UCL Epidemiology & Public Health). "We find that common causes of tooth loss and mental and physical decline are often linked to socioeconomic status, highlighting the importance of broader social determinants such as education and wealth to improve the oral and general health of the poorest members of society.
"Regardless of what is behind the link between tooth loss and decline in function, recognising excessive tooth loss presents an opportunity for early identification of adults at higher risk of faster mental and physical decline later in their life. There are many factors likely to influence this decline, such as lifestyle and psychosocial factors, which are amenable to change."
Science Daily/SOURCE :http://www.sciencedaily.com/releases/2014/12/141218210023.htm
After learning new words, brain sees them as pictures
March 24, 2015
Science Daily/Georgetown University Medical Center
When we look at a known word, our brain sees it like a picture, not a group of letters needing to be processed. That's the finding from a new study that shows the brain learns words quickly by tuning neurons to respond to a complete word, not parts of it.
Neurons respond differently to real words, such as turf, than to nonsense words, such as turt, showing that a small area of the brain is "holistically tuned" to recognize complete words, says the study's senior author, Maximilian Riesenhuber, PhD, who leads the GUMC Laboratory for Computational Cognitive Neuroscience.
"We are not recognizing words by quickly spelling them out or identifying parts of words, as some researchers have suggested. Instead, neurons in a small brain area remember how the whole word looks -- using what could be called a visual dictionary," he says.
This small area in the brain, called the visual word form area, is found in the left side of the visual cortex, opposite from the fusiform face area on the right side, which remembers how faces look. "One area is selective for a whole face, allowing us to quickly recognize people, and the other is selective for a whole word, which helps us read quickly," Riesenhuber says.
The study asked 25 adult participants to learn a set of 150 nonsense words. The brain plasticity associated with learning was investigated with functional magnetic resonance imaging (fMRI), both before and after training.
Using a specific fMRI technique know as fMRI-rapid adaptation, the investigators found that the visual word form area changed as the participants learned the nonsense words. Before training the neurons responded like the training words were nonsense words, but after training the neurons responded to the learned words like they were real words. "This study is the first of its kind to show how neurons change their tuning with learning words, demonstrating the brain's plasticity," says the study's lead author, Laurie Glezer, PhD.
The findings not only help reveal how the brain processes words, but also provides insights into how to help people with reading disabilities, says Riesenhuber. "For people who cannot learn words by phonetically spelling them out -- which is the usual method for teaching reading -- learning the whole word as a visual object may be a good strategy."
In fact, after the team's first groundbreaking study on the visual dictionary was published in Neuron in 2009, Riesenhuber says they were contacted by a number of people who had experienced reading difficulties and teachers helping people with reading difficulties, reporting that learning word as visual objects helped a great deal. That study revealed the existence of a neural representation for whole written real words -- also known as an orthographic lexicon --the current study now shows how novel words can become incorporated after learning in this lexicon.
"The visual word form area does not care how the word sounds, just how the letters of the word look together," he says. "The fact that this kind of learning only happens in one very small part of the brain is a nice example of selective plasticity in the brain."
Science Daily/SOURCE :http://www.sciencedaily.com/releases/2015/03/150324183623.htm
Eating green leafy vegetables keeps mental abilities sharp
March 30, 2015
Science Daily/Federation of American Societies for Experimental Biology (FASEB)
Something as easy as adding more spinach, kale, collards and mustard greens to your diet could help slow cognitive decline, according to new research. The study also examined the nutrients responsible for the effect, linking vitamin K consumption to slower cognitive decline for the first time.
"Losing one's memory or cognitive abilities is one of the biggest fears for people as they get older," said Martha Clare Morris, Sc.D., assistant provost for community research at Rush University Medical Center and leader of the research team. "Since declining cognitive ability is central to Alzheimer's disease and dementias, increasing consumption of green leafy vegetables could offer a very simple, affordable and non-invasive way of potentially protecting your brain from Alzheimer's disease and dementia."
The researchers tracked the diets and cognitive abilities of more than 950 older adults for an average of five years and saw a significant decrease in the rate of cognitive decline for study participants who consumed greater amounts of green leafy vegetables. People who ate one to two servings per day had the cognitive ability of a person 11 years younger than those who consumed none.
When the researchers examined individual nutrients linked with slowing cognitive decline, they found that vitamin K, lutein, folate and beta-carotene were most likely helping to keep the brain healthy.
"Our study identified some very novel associations," said Morris, who will present the research at the American Society for Nutrition (ASN) Annual Meeting during Experimental Biology 2015. "No other studies have looked at vitamin K in relation to change in cognitive abilities over time, and only a limited number of studies have found some association with lutein." Other studies have linked folate and beta-carotene intake with slower cognitive decline.
To conduct the study, Morris' research team gathered data from 954 participants from the Memory and Aging Project, which aims to identify factors associated with the maintenance of cognitive health. The participants, whose age averaged 81, reported their daily food and beverage intake by answering a detailed 144-item questionnaire at the beginning of the study. The researchers computed the total daily nutrients by combining the nutrient content for each food consumed with the number of servings eaten each day. They followed participants for 2 to 10 years, assessing cognition annually with a comprehensive battery of 19 tests and adjusted for age, sex, education, smoking, genetic risk for Alzheimer's disease and participation in physical activities when estimating the effects of diet on cognitive decline.
"With baby boomers approaching old age, there is huge public demand for lifestyle behaviors that can ward off loss of memory and other cognitive abilities with age," said Morris. "Our study provides evidence that eating green leafy vegetables and other foods rich in vitamin K, lutein and beta-carotene can help to keep the brain healthy to preserve functioning."
In addition to green leafy vegetables, other good sources of vitamin K, lutein, folate and beta-carotene include brightly colored fruits and vegetables.
Science Daily/SOURCE :http://www.sciencedaily.com/releases/2015/03/150330112227.htm
The brain game: How decreased neural activity may help you learn faster
April 6, 2015
Science Daily/University of California - Santa Barbara
Why are some people able to master a new skill quickly while others require extra time or practice? Counterintuitive as it may seem, study participants who showed decreased neural activity learned the fastest. The critical distinction was in areas not directly related to seeing the cues or playing the notes that participants were trying to learn: the frontal cortex and the anterior cingulate cortex. These cognitive control centers are thought to be most responsible for what is known as executive function. The frontal cortex and the anterior cingulate cortex are among the last brain regions to fully develop in humans, which may help explain why children are able to acquire new skills quickly as compared to adults.
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Why are some people able to master a new skill quickly while others require extra time or practice? That was the question posed by UC Santa Barbara's Scott Grafton and colleagues at the University of Pennsylvania and Johns Hopkins University.
To find the answer, the team designed a study that measured the connections between different brain regions while participants learned to play a simple game.
The researchers discovered that the neural activity in the quickest learners was different from that of the slowest. Their analysis provides new insight into what happens in the brain during the learning process and sheds light on the role of interactions between different regions. The findings, which appear online today in Nature Neuroscience, suggest that recruiting unnecessary parts of the brain for a given task -- similar to overthinking the problem -- plays a critical role in this important difference.
"It's useful to think of your brain as housing a very large toolkit," said Grafton, a professor in UCSB's Department of Psychological & Brain Sciences. "When you start to learn a challenging new skill, such as playing a musical instrument, your brain uses many different tools in a desperate attempt to produce anything remotely close to music. With time and practice, fewer tools are needed and core motor areas are able to support most of the behavior. What our laboratory study shows is that beyond a certain amount of practice, some of these cognitive tools might actually be getting in the way of further learning."
At UCSB's Brain Imaging Center, study participants played a simple game while their brains were scanned with fMRI. The technique measures neural activity by tracking the flow of blood in the brain, highlighting which regions are involved in a given task.
Participants responded to a sequence of color-coded notes by pressing the corresponding button on a hand-held controller. Six predetermined sequences of 10 notes each were shown multiple times during the scanning sessions. Subjects were instructed to play the sequences as quickly and as accurately as possible, responding to the cues they saw on a screen.
The study continued with participants practicing at home while researchers monitored their activity remotely. Subjects returned to the Brain Imaging Center at two-, four- and six-week intervals for new scans that demonstrated how well practice had helped them master the skill. Completion time for all participants dropped over the course of the study but did so at different rates. Some picked up the sequences immediately, while others gradually improved over the six-week period.
The complexities of learning
Lead author Danielle Bassett, an expert in network science, developed novel analysis methods to determine what was happening in the participants' brains that correlated with these differences. But rather than trying to find a single spot in the brain that was more or less active, the team investigated the learning process as the function of a complex, dynamic network involving various regions of the brain.
"We weren't using the traditional fMRI approach where you pick a region of interest and see if it lights up," said Bassett, the Skirkanich Assistant Professor of Innovation at the University of Pennsylvania. "We looked at the whole brain at once and saw which parts were communicating with each other the most."
The investigators compared the activation patterns of 112 anatomical regions of the brain and measured the degree to which they mirrored one another. The more the patterns of two regions matched, the more they were considered to be in communication. By graphing those connections, the team found that hotspots of highly interconnected regions emerged.
"When network scientists look at these graphs, they see what is known as community structure," Bassett said. "There are sets of nodes in a network that are really densely interconnected to each other. Everything else is either independent or very loosely connected with only a few lines."
The team used a technique known as dynamic community detection, a method that employs algorithms to determine which nodes are incorporated into these clusters and how their interactions change over time. This allowed the researchers to measure how common it was for any two nodes to remain in the same cluster while subjects practiced the same sequence some 10 times. Through these comparisons, they found overarching trends about how regions responsible for different functions worked together.
The researchers discovered that the visual and the motor blocks had a lot of connectivity during the first few trials, but as the experiment progressed they became essentially autonomous. For example, the part of the brain that controls finger movement and the part that processes visual stimulus didn't really interact at all by the end of the experiment.
According to Grafton, in some ways this trend was not surprising since the team was essentially seeing the learning process on the neurological level, with the participants' brains reorganizing the flow of activity as they mastered this new skill.
"Previous brain imaging research has mostly looked at skill learning over -- at most -- a few days of practice, which is silly," said Grafton, who is also a member of UCSB's Institute for Collaborative Biotechnologies. "Who ever learned to play the violin in an afternoon? By studying the effects of dedicated practice over many weeks, we gain insight into never before observed changes in the brain. These reveal fundamental insights into skill learning that are akin to the kinds of learning we must achieve in the real world."
Comparing executive function
With the neurological correlates of the learning process coming into focus, the scientists were able to delve into the differences among participants in order to explain why some learned the sequences faster than others. Counterintuitive as it may seem, the participants who showed decreased neural activity learned the fastest. The critical distinction was in areas not directly related to seeing the cues or playing the notes: the frontal cortex and the anterior cingulate cortex.
These cognitive control centers are thought to be most responsible for what is known as executive function. "This neurological trait is associated with making and following through with plans, spotting and avoiding errors and other higher-order types of thinking," Grafton said. "In fact, good executive function is necessary for complex tasks but might actually be a hindrance to mastering simple ones."
Grafton also noted that the frontal cortex and the anterior cingulate cortex are among the last brain regions to fully develop in humans, which may help explain why children are able to acquire new skills quickly as compared to adults.
"It's the people who can turn off the communication to these parts of their brain the quickest who have the steepest drop-off in their completion times," said Bassett. "It seems like those other parts are getting in the way for the slower learners. It's almost like they're trying too hard and overthinking it."
Additional studies will delve into why some people are better than others at shutting down the connections in these parts of the brains.
Science Daily/SOURCE :http://www.sciencedaily.com/releases/2015/04/150406121348.htm
Food for thought: Master protein enhances learning and memory
April 7, 2015
Science Daily/Salk Institute for Biological Studies
Just as some people seem built to run marathons and have an easier time going for miles without tiring, others are born with a knack for memorizing things, from times tables to trivia facts. These two skills -- running and memorizing -- are not so different as it turns out. Researchers have discovered a single protein that energizes muscles and the brain, which could point to potential treatments in regenerative and developmental medicine as well as ways to address defects in learning and memory, they say.
Salk scientists and collaborators have discovered that physical and mental activities rely on a single metabolic protein that controls the flow of blood and nutrients throughout the body, as reported in the journal Cell Metabolism. The new study could point to potential treatments in regenerative and developmental medicine as well as ways to address defects in learning and memory.
"This is all about getting energy where it's needed to 'the power plants' in the body," says Ronald Evans, director of Salk's Gene Expression Laboratory and senior author of the new paper, published April 7, 2015. "The heart and muscles need a surge of energy to carry out exercise and neurons need a surge of energy to form new memories."
Energy for muscles and brains, the scientists discovered, is controlled by a single protein called estrogen-related receptor gamma (ERRγ). Evans' research group has previously studied the role of ERRγ in the heart and skeletal muscles. In 2011, they discovered that promoting ERRγ activity in the muscle of sedentary mice increased blood supply to their muscles and doubled their running capacity. ERRγ, they went on to show, turns on a whole host of muscle genes that convert fat to energy.
Thus, ERRγ became known as a master metabolic switch that energized muscle to enhance performance. Although studies had also shown that ERRγ was active in the brain, researchers didn't understand why -- the brain burns sugar and ERRγ was previously shown to only burn fat. So the team decided to look more closely at what the protein was doing in brain cells.
By first looking at isolated neurons, Liming Pei, lead and co-corresponding author of the paper, found that, as in muscle, ERRγ activates dozens of metabolic genes in brain cells. Unexpectedly, this activation related to sugar instead of fat. Neurons that lacked ERRγ could not ramp up energy production and thus had a compromised performance.
"We assumed that ERRγ did the same thing throughout the body," says Evans. "But we learned that it's different in the brain." ERRγ, they now conclude, turns on fat-burning pathways in muscles and sugar-burning pathways in the brain.
Evans and his collaborators noticed that ERRγ in live mice was most active in the hippocampus -- an area of the brain that is active in producing new brain cells, is involved in learning and memory and is known to require lots of energy. They wondered whether ERRγ had a direct role in learning and memory. By studying mice lacking ERRγ in the brain, they found a link.
While mice without the protein had normal vision, movement and balance, they were slower at learning how to swim through a water maze -- and poor at remembering the maze on subsequent trials -- compared to mice with normal levels of ERRγ.
"What we found is that mice that missing ERRγ are basically very slow learners," says Pei. Varying levels of ERRγ could also be at the root of differences between how individual humans learn, he hypothesizes. "Everyone can learn, but some people learn and memorize more efficiently than others, and we now think this could be linked to changes in brain metabolism."
A better understanding of the metabolism of neurons could help point the way to improved treatments for learning and attention disorders. And possibly, revving up levels of ERRγ could even enhance learning, just as it enhances muscle function.
"What we've shown is that memories are really built on a metabolic scaffold," says Evans. "And we think that if you want to understand learning and memory, you need to understand the circuits that underlie and power this process."
http://www.sciencedaily.com/releases/2015/04/150407123052.htm
Poor sleep linked to toxic buildup of Alzheimer's protein, memory loss
June 1, 2015
Science Daily/University of California - Berkeley
Sleep may be a missing piece of the Alzheimer's puzzle. The toxic protein that is the hallmark of Alzheimer's disease blocks the deepest stages of sleep, resulting in memory decline, according to new research
Scientists at the University of California, Berkeley, have found compelling evidence that poor sleep -- particularly a deficit of the deep, restorative slumber needed to hit the save button on memories -- is a channel through which the beta-amyloid protein believed to trigger Alzheimer's disease attacks the brain's long-term memory.
"Our findings reveal a new pathway through which Alzheimer's disease may cause memory decline later in life," said UC Berkeley neuroscience professor Matthew Walker, senior author of the study to be published in the journal Nature Neuroscience.
Excessive deposits of beta-amyloid are key suspects in the pathology of Alzheimer's disease, a virulent form of dementia caused by the gradual death of brain cells. An unprecedented wave of aging baby boomers is expected to make Alzheimer's disease, which has been diagnosed in more than 40 million people, one of the world's fastest-growing and most debilitating public health concerns.
The good news about the findings, Walker said, is that poor sleep is potentially treatable and can be enhanced through exercise, behavioral therapy and even electrical stimulation that amplifies brain waves during sleep, a technology that has been used successfully in young adults to increase their overnight memory.
"This discovery offers hope," he said. "Sleep could be a novel therapeutic target for fighting back against memory impairment in older adults and even those with dementia."
The study was co-led by UC Berkeley neuroscientists Bryce Mander and William Jagust, a leading expert on Alzheimer's disease. The team has received a major National Institutes of Health grant to conduct a longitudinal study to test their hypothesis that sleep is an early warning sign or biomarker of Alzheimer's disease.
While most research in this area has depended on animal subjects, this latest study has the advantage of human subjects recruited by Jagust, a professor with joint appointments at UC Berkeley's Helen Wills Neuroscience Institute, the School of Public Health and the Lawrence Berkeley National Laboratory.
"Over the past few years, the links between sleep, beta-amyloid, memory, and Alzheimer's disease have been growing stronger," Jagust said. "Our study shows that this beta-amyloid deposition may lead to a vicious cycle in which sleep is further disturbed and memory impaired."
Using a powerful combination of brain imaging and other diagnostic tools on 26 older adults who have not been diagnosed with dementia, researchers looked for the link between bad sleep, poor memory and the toxic accumulation of beta-amyloid proteins.
"The data we've collected are very suggestive that there's a causal link," said Mander, lead author of the study and a postdoctoral researcher in the Sleep and Neuroimaging Laboratory directed by Walker. "If we intervene to improve sleep, perhaps we can break that causal chain."
A buildup of beta-amyloid has been found in Alzheimer's patients and, independently, in people reporting sleep disorders. Moreover, a 2013 University of Rochester study found that the brain cells of mice would shrink during non-rapid-eye-movement (non-REM) sleep to make space for cerebrospinal fluids to wash out toxic metabolites such as beta-amyloid.
"Sleep is helping wash away toxic proteins at night, preventing them from building up and from potentially destroying brain cells," Walker said. "It's providing a power cleanse for the brain."
Specifically, the researchers looked at how the quantity of beta-amyloid in the brain's medial frontal lobe impairs deep non-REM sleep, which we need to retain and consolidate fact-based memories.
In a previous study, Mander, Jagust and Walker found that the powerful brain waves generated during non-REM sleep play a key role in transferring memories from the hippocampus -- which supports short-term storage for information -- to longer-term storage in the frontal cortex. In elderly people, deterioration of this frontal region of the brain has been linked to poor-quality sleep.
For this latest study, researchers used positron emission tomography (PET) scans to measure the accumulation of beta-amyloid in the brain; functional Magnetic Resonance Imaging (fMRI) to measure activity in the brain during memory tasks; an electroencephalographic (EEG) machine to measure brain waves during sleep; and statistical models to analyze all the data.
The research was performed on 26 older adults, between the ages of 65 and 81, who showed no existing evidence of dementia or other neurodegenerative, sleep or psychiatric disorders. First, they each received PET scans to measure levels of beta-amyloid in the brain, after which they were tasked with memorizing 120 word pairs, and then tested on how well they remembered a portion of them.
The study participants then slept for eight hours, during which EEG measured their brain waves. The following morning, their brains were scanned using fMRI as they recalled the remaining word pairs. At this point, researchers tracked activity in the hippocampus, where memories are temporarily stored before they are transferred to the prefrontal cortex.
"The more you remember following a good night of sleep, the less you depend on the hippocampus and the more you use the cortex," Walker said. "It's the equivalent of retrieving files from the safe storage site of your computer's hard drive, rather than the temporary storage of a USB stick."
Overall, the results showed that the study participants with the highest levels of beta-amyloid in the medial frontal cortex had the poorest quality of sleep and, consequently, performed worst on the memory test the following morning, with some forgetting more than half of the information they had memorized the previous day.
"The more beta-amyloid you have in certain parts of your brain, the less deep sleep you get and, consequently, the worse your memory," Walker said. "Additionally, the less deep sleep you have, the less effective you are at clearing out this bad protein. It's a vicious cycle.
"But we don't yet know which of these two factors -- the bad sleep or the bad protein -- initially begins this cycle. Which one is the finger that flicks the first domino, triggering the cascade?" Walker added.
And that's what the researchers will determine as they track a new set of older adults over the next five years.
"This is a new pathway linking Alzheimer's disease to memory loss, and it's an important one because we can do something about it," Mander said.
Science Daily/SOURCE :http://www.sciencedaily.com/releases/2015/06/150601122442.htm
Musical tastes offer a window into how you think
July 22, 2015
Science Daily/University of Cambridge
Do you like your jazz to be Norah Jones or Ornette Coleman, your classical music to be Bach or Stravinsky, or your rock to be Coldplay or Slayer? The answer could give an insight into the way you think, say researchers.
In a study published today in the journal PLOS ONE, a team of psychologists show that your thinking style -- whether you are an 'empathizer' who likes to focus on and respond to the emotions of others, or a 'systemizer' who likes to analyse rules and patterns in the world--is a predictor of the type of music you like.
Music is a prominent feature of everyday life and nearly everywhere we go. It's easy for us to know what types of music we like and don't like. When shuffling songs on an iPod, it takes us only a few seconds to decide whether to listen or skip to the next track. However, little is known about what determines our taste in music.
Researchers over the past decade have argued that musical preferences reflect explicit characteristics such as age and personality. For example, people who are open to new experiences tend to prefer music from the blues, jazz, classical, and folk genres, and people who are extraverted and 'agreeable' tend to prefer music from the pop, soundtrack, religious, soul, funk, electronic, and dance genres.
Now a team of scientists, led by PhD student David Greenberg, has looked at how our 'cognitive style' influences our musical choices. This is measured by looking at whether an individual scores highly on 'empathy' (our ability to recognize and react to the thoughts and feelings of others) or on 'systemizing' (our interest in understanding the rules underpinning systems such as the weather, music, or car engines) -- or whether we have a balance of both.
"Although people's music choices fluctuates over time, we've discovered a person's empathy levels and thinking style predicts what kind of music they like," said David Greenberg from the Department of Psychology. "In fact, their cognitive style -- whether they're strong on empathy or strong on systems -- can be a better predictor of what music they like than their personality."
The researchers conducted multiple studies with over 4,000 participants, who were recruited mainly through the myPersonality Facebook app. The app asked Facebook users to take a selection of psychology-based questionnaires, the results of which they could place on their profiles for other users to see. At a later date, they were asked to listen to and rate 50 musical pieces. The researchers used library examples of musical stimuli from 26 genres and subgenres, to minimise the chances that participants would have any personal or cultural association with the piece of music.
People who scored high on empathy tended to prefer mellow music (from R&B, soft rock, and adult contemporary genres), unpretentious music (from country, folk, and singer/songwriter genres) and contemporary music (from electronica, Latin, acid jazz, and Euro pop). They disliked intense music, such as punk and heavy metal. In contrast, people who scored high on systemizing favoured intense music, but disliked mellow and unpretentious musical styles.
The results proved consistent even within specified genres: empathizers preferred mellow, unpretentious jazz, while systemizers preferred intense, sophisticated (complex and avant-garde) jazz.
The researchers then looked more in-depth and found those who scored high on empathy preferred music that had low energy (gentle, reflective, sensual, and warm elements), or negative emotions (sad and depressing characteristics), or emotional depth (poetic, relaxing, and thoughtful features). Those who scored high on systemizing preferred music that had high energy (strong, tense, and thrilling elements), or positive emotions (animated and fun features), and which also featured a high degree of cerebral depth and complexity.
David Greenberg, a trained jazz saxophonist, says the research could have implications for the music industry. "A lot of money is put into algorithms to choose what music you may want to listen to, for example on Spotify and Apple Music. By knowing an individual's thinking style, such services might in future be able to fine tune their music recommendations to an individual."
Dr Jason Rentfrow, the senior author on the study says: "This line of research highlights how music is a mirror of the self. Music is an expression of who we are emotionally, socially, and cognitively."
Professor Simon Baron-Cohen, a member of the team, added; "This new study is a fascinating extension to the 'empathizing-systemizing' theory of psychological individual differences. It took a talented PhD student and musician to even think to pose this question. The research may help us understand those at the extremes, such as people with autism, who are strong systemizers."
Based on their findings, the following are songs that the researchers believe are likely to fit particular styles:
High on empathy
Hallelujah -- Jeff Buckley
Come away with me -- Norah Jones
All of me -- Billie Holliday
Crazy little thing called love -- Queen
High on systemizing
Concerto in C -- Antonio Vivaldi
Etude Opus 65 No 3 -- Alexander Scriabin
God save the Queen -- The Sex Pistols
Enter the Sandman -- Metallica
Science Daily/SOURCE :http://www.sciencedaily.com/releases/2015/07/150722144648.htm
Nine risk factors may contribute to two-thirds of Alzheimer's cases worldwide
August 20, 2015
Science Daily/BMJ
All potentially modifiable; could prove promising options for prevention, say researchers
Nine potentially modifiable risk factors may contribute to up to two-thirds of Alzheimer's disease cases worldwide, suggests an analysis of the available evidence.
The analysis indicates the complexity of Alzheimer's disease development and just how varied the risk factors for it are.
But the researchers suggest that preventive strategies, targeting diet, drugs, body chemistry, mental health, pre-existing disease, and lifestyle may help to stave off dementia. This could be particularly important, given that, as yet, there is no cure, they say.
The researchers wanted to look at the factors associated with the development of Alzheimer's disease in a bid to determine the degree to which these might be modified and so potentially reduce overall risk.
They therefore trawled key research databases, looking for relevant studies published in English from 1968 up to July 2014.
Out of almost 17,000 studies, 323, covering 93 different potential risk factors and more than 5000 people, were suitable for inclusion in the analysis. The researchers pooled the data from each of the studies and graded the evidence according to its strength.
They found grade 1 level evidence in favour of a protective effect for the female hormone oestrogen, cholesterol lowering drugs (statins), drugs to lower high blood pressure, and anti-inflammatory drugs (NSAIDs).
They found the same level of evidence for folate, vitamins C and E, and coffee, all of which were associated with helping to stave off the disease.
Similarly, the pooled data indicated a strong association between high levels of homocysteine--an amino acid manufactured in the body--and depression and a significantly heightened risk of developing Alzheimer's disease.
The evidence also strongly pointed to the complex roles of pre-existing conditions as either heightening or lowering the risk.
The factors associated with a heightened risk included frailty, carotid artery narrowing, high and low blood pressure, and type 2 diabetes (in the Asian population). Those associated with a lowered risk included a history of arthritis, heart disease, metabolic syndrome, and cancer.
Certain factors seemed to be linked to altered risk, depending on the time of life and ethnic background.
For example, high or low body mass index (BMI) in mid-life and low educational attainment were associated with increased risk, whereas high BMI in later life, exercising one's brain, current smoking (excluding the Asian population), light to moderate drinking, and stress were associated with lowered risk.
There were no significant associations found for workplace factors.
The researchers then assessed the population attributable risk (PAR) for nine risk factors which had strong evidence in favour of an association with Alzheimer's disease in the pooled analysis, and for which there are data on global prevalence.
PAR refers to a mathematical formula used to define the proportion of disease in a defined population that would disappear if exposure to a specific risk factor were to be eliminated.
The nine risk factors included obesity, current smoking (in the Asian population), carotid artery narrowing, type 2 diabetes (in the Asian population), low educational attainment, high levels of homocysteine, depression, high blood pressure and frailty.
The combined PAR indicated that these nine factors, each of which is potentially modifiable, contribute up to around two thirds of cases globally.
This is an observational study, so no definitive conclusions can be drawn about cause and effect, but the researchers suggest that preventive strategies, targeting diet, prescription drugs, body chemistry, mental health, underlying disease, and lifestyle might help curb the number of new cases of Alzheimer's disease.
Science Daily/SOURCE :http://www.sciencedaily.com/releases/2015/08/150820190257.htm
Effect of physical activity on cognition
August 25, 2015
Science Daily/The JAMA Network Journals
Kaycee M. Sink, M.D., M.A.S., of the Wake Forest School of Medicine, Winston-Salem, N.C., and colleagues evaluated whether a 24-month physical activity program would result in better cognitive function, lower risk of mild cognitive impairment (MCI) or dementia, or both, compared with a health education program.
Epidemiological evidence suggests that physical activity is associated with lower rates of cognitive decline. Exercise is associated with improved cerebral blood flow and neuronal connectivity and maintenance or improvement in brain volume. However, evidence from randomized trials has been limited and mixed, according to background information in the article.
Participants in the Lifestyle Interventions and Independence for Elders (LIFE) study (n = 1,635; 70 to 89 years of age) were randomly assigned to a structured, moderate-intensity physical activity program (n = 818) that included walking, resistance training, and flexibility exercises or a health education program (n = 817) of educational workshops and upper-extremity stretching. Participants were sedentary adults who were at risk for mobility disability but able to walk about a quarter mile. Measures of cognitive function and incident MCI or dementia were determined at 24 months.
The researchers found that the moderate-intensity physical activity intervention did not result in better global or domain-specific cognition compared with the health education program. There was also no significant difference between groups in the incidence of MCI or dementia (13.2 percent in the physical activity group vs 12.1 percent in the health education group), although this outcome had limited statistical power.
"Cognitive function remained stable over 2 years for all participants. We cannot rule out that both interventions were successful at maintaining cognitive function," the authors write.
Participants in the physical activity group who were 80 years or older and those with poorer baseline physical performance had better changes in executive function composite scores compared with the health education group. "This finding is important because executive function is the most sensitive cognitive domain to exercise interventions, and preserving it is required for independence in instrumental activities of daily living. Future physical activity interventions, particularly in vulnerable older adult groups (e.g., 80 years of age and those with especially diminished physical functioning levels), may be warranted."
Science Daily/SOURCE :http://www.sciencedaily.com/releases/2015/08/150825115022.htm
Neurobiology: Light-activated learning
August 28, 2015
Science Daily/Ludwig-Maximilians-Universitaet Muenchen (LMU)
Scientists have developed a light-sensitive switch that regulates a protein implicated in the neurobiology of synaptic plasticity. The agent promises to shed new light on the phenomenology of learning, memory and neurodegeneration.
Learning is made possible by the fact that the functional connections between nerve cells in the brain are subject to constant remodeling. As a result of activation-dependent modification of these links ('synaptic plasticity'), circuits that are repeatedly stimulated "learn" to transmit signals ever more efficiently. This process is thought to provide the molecular basis for learning and memory, allowing the information encoded in such networks to be recalled and exploited in novel situations. The primary targets for modification are the specialized receptor proteins in nerve-cell membranes that mediate the transmission of electrical signals between individual neurons. A team of researchers led by Dirk Trauner, Professor of Chemical Biology and Genetics at LMU, in collaboration with colleagues at the Institut Pasteur in Paris, has now synthesized a light-dependent switch that enables them to control the activity of a particular class of receptors which is crucial for the formation and storage of memories. The compound provides a powerful new tool for researchers interested in probing the mechanisms that underlie short- and long-term memory. The results appear in the online journal Nature Communications.
Individual nerve cells generally use chemical messengers to communicate with each other. These so-called neurotransmitters are released by specialized structures called synapses at the end of the signal-transmitting fiber (the axon) and diffuse across the synaptic cleft -- the narrow gap that separates nerve cells from each other. The chemical then binds to receptors on the "post-synaptic" neuron. How the post-synaptic cell reacts is dependent on the nature of the neurotransmitter and the corresponding receptor. "In this context, the so-called NMDA receptor is very special," says Laura Laprell, a PhD student in Trauner's group and joint first author of the new study. "It is primarily responsible for the fact that we have the capacity to form memories and the ability to learn."
Regulation with millisecond precision
Trauner and his colleagues have synthesized a chemical called azobenzene-triazole-glutamate (ATG), which acts as a light-sensitive neurotransmitter on NMDA receptors. With the aid of this tool, it is now possible, for the first time, to activate -- and inactivate -- these receptors with high specificity and precision in the laboratory. Moreover, in contrast to other optical switches, ATG does not permanently bind to the receptor, but diffuses freely in the synaptic cleft between pre- and post-synaptic neurons. "ATG is completely inactive in the dark," Laprell explains, "and must be exposed to light before it can bind to the receptor and initiate depolarization of the post-synaptic cell." In other words, in order to be activated, the nerve cells must first 'see the light'. Subsequent irradiation with UV light inactivates ATG within a matter of milliseconds, thus enabling extremely precise control of receptor activation in the time domain.
Because light can be controlled with extraordinary precision, both spatially and temporally, it offers a highly versatile means of regulating biological processes. However, the spectral composition of the light must be taken into consideration, as light can also damage tissues. This explains why photoswitches that are activated by less energetic light rays with longer wavelengths are of particular interest. "And ATG fulfils this requirement: It is not only completely inactive in the dark -- and therefore has no side-effects, it is also exceptional in that it can be activated with high precision by red light. For this purpose, we make use of 'two-photon activation', a state-of-the-art method in which the molecule is exposed to two low-energy light quanta in rapid succession," Trauner explains. "Red light also has the advantage that it penetrates deeper into living tissue."
The researchers expect that their new-found capacity to regulate the activation of NMDA receptors will lead to new insights into the mechanisms underlying synaptic plasticity and memory formation. NMDA receptors may also be involved in precipitating or exacerbating neurodegenerative diseases such as Alzheimer's and Parkinson's. "A better understanding of this class of receptors, coupled with the ability to control their activity, is therefore of great interest in this context too," Trauner points out. "We are now cooperating with other groups who want to use ATG specifically to understand the role of these receptors in neurodegenerative conditions."
Science Daily/SOURCE :http://www.sciencedaily.com/releases/2015/08/150828081456.htm
Resveratrol impacts Alzheimer's disease biomarker
September 11, 2015
Science Daily/Georgetown University Medical Center
The largest nationwide clinical trial to study high-dose resveratrol long-term in people with mild to moderate Alzheimer's disease found that a biomarker that declines when the disease progresses was stabilized in people who took the purified form of resveratrol. Resveratrol is a naturally occurring compound found in foods such as red grapes, raspberries, dark chocolate and some red wines.
Resveratrol is a naturally occurring compound found in foods such as red grapes, raspberries, dark chocolate and some red wines.
The results, published online in Neurology, "are very interesting," says the study's principal investigator, R. Scott Turner, MD, PhD, director of the Memory Disorders Program at Georgetown University Medical Center. Turner, who treats patients at MedStar Georgetown University Hospital, cautions that the findings cannot be used to recommend resveratrol. "This is a single, small study with findings that call for further research to interpret properly."
The resveratrol clinical trial was a randomized, phase II, placebo-controlled, double blind study in patients with mild to moderate dementia due to Alzheimer's disease. An "investigational new drug" application was required by the U.S. Food and Drug Administration to test the pure synthetic (pharmaceutical-grade) resveratrol in the study. It is not available commercially in this form.
The study enrolled 119 participants. The highest dose of resveratrol tested was one gram by mouth twice daily -- equivalent to the amount found in about 1,000 bottles of red wine.
John Bozza, 80, participated in the study. Five years ago, his wife, Diana, began noticing "something wasn't quite right." He was diagnosed with mild cognitive impairment, but only a year later, his condition progressed to mild Alzheimer's.
Diana, whose twin sister died from the same disease, says there are multiple reasons she and John decided to participate in the resveratrol study, and they now know he was assigned to take the active drug.
"I definitely want the medical community to find a cure," she says. "And of course I thought there's always a chance that John could have been helped, and who knows, maybe he was."
Patients, like John, who were treated with increasing doses of resveratrol over 12 months showed little or no change in amyloid-beta40 (Abeta40) levels in blood and cerebrospinal fluid. In contrast, those taking a placebo had a decrease in the levels of Abeta40 compared with their levels at the beginning of the study.
"A decrease in Abeta40 is seen as dementia worsens and Alzheimer's disease progresses; still, we can't conclude from this study that the effects of resveratrol treatment are beneficial," Turner explains. "It does appear that resveratrol was able to penetrate the blood brain barrier, which is an important observation. Resveratrol was measured in both blood and cerebrospinal fluid."
The researchers studied resveratrol because it activates proteins called sirtuins, the same proteins activated by caloric restriction. The biggest risk factor for developing Alzheimer's is aging, and studies with animals found that most age-related diseases--including Alzheimer's--can be prevented or delayed by long-term caloric restriction (consuming two-thirds the normal caloric intake).
Turner says the study also found that resveratrol was safe and well tolerated. The most common side effects experienced by participants were gastrointestinal-related, including nausea and diarrhea. Also, patients taking resveratrol experienced weight loss while those on placebo gained weight.
One outcome in particular was confounding, Turner notes. The researchers obtained brain MRI scans on participants before and after the study, and found that resveratrol-treated patients lost more brain volume than the placebo-treated group.
"We're not sure how to interpret this finding. A similar decrease in brain volume was found with some anti-amyloid immunotherapy trials," Turner adds. A working hypothesis is that the treatments may reduce inflammation (or brain swelling) found with Alzheimer's.
The study, funded by the National Institute on Aging and conducted with the Alzheimer's Disease Cooperative Study, began in 2012 and ended in 2014. GUMC was one of 21 participating medical centers across the U.S.
Further studies, including analysis of frozen blood and cerebrospinal fluid taken from patients, are underway to test possible drug mechanisms.
"Given safety and positive trends toward effectiveness in this phase 2 study, a larger phase 3 study is warranted to test whether resveratrol is effective for individuals with Alzheimer's -- or at risk for Alzheimer's," Turner says.
Resveratrol and similar compounds are being tested in many age-related disorders including cancer, diabetes and neurodegenerative disorders. The study Turner led, however, is the largest, longest and highest dose trial of resveratrol in humans to date.
Science Daily/SOURCE :http://www.sciencedaily.com/releases/2015/09/150911164211.htm
Increased memory with a flash of light
Scientists create a new light-sensitive, plant-human hybrid protein to efficiently modulate calcium channels
September 14, 2015
Science Daily/Institute for Basic Science
The burgeoning field of optogenetics has seen another breakthrough with the creation of a new plant-human hybrid protein molecule called OptoSTIM1. In South Korea, a research team led by Won Do Heo, associate professor at the Korea Advanced Institute of Science and Technology (KAIST) and group leader at the IBS Center for Cognition and Sociality, together with Professor Yong-Mahn Han and Professor Daesoon Kim, have refined the process for precision control of cellular calcium (Ca2+) channels in living organisms with their new OptoSTIM1 molecule.
Calcium ions are a crucial part of diverse cellular functions such as contraction, excitation, growth, differentiation and death. Severe Ca2+ deficiency is linked to cardiac arrhythmia, cognitive impairment, and ataxia.
In optogenetics, a light-sensitive plant photoreceptor and an animal protein that affects cell membrane ion channels, bind together and are introduced to target cells. They work together and respond to a stimulus from a particular wavelength of light to open (or close) a particular ion channel.
Previous attempts at precision control of calcium channels using drugs and electrical stimulation were not accurate enough for meaningful results. What revolutionized the process of specified Ca2+ channel control was the invention of the field of optogenetics.
In their optogenetic application, the Korean team used a photoreceptor protein called cryptochrome 2 (Cry2) from a small, flowering plant Arabidopsis thaliana, and combined it with the STromal Interaction Molecule 1 (STIM1), a protein found in almost all animals, which opens cellular Ca2+ channels. This resulted in a hybrid molecule that they named OptoSTIM1.
When they introduced a blue light to the OptoSTIM1 expressing cells, they were able to coax them to open their Ca2+ channels and allow an influx of calcium ions from outside the cell. The amount of Ca2+ which cells took up surpassed previous experiments due to OptoSTIM1 being more efficient than previous optogenetic molecules. Cry2 has a natural affinity for clustering under blue light. According to researcher Taeyoon Kyung, "Our method worked better because other plant proteins are not as efficient as Cry2 at clustering." In fact, this clustering resulted in 5-10 times more detected Ca2+ than in previous studies.
Increasing learning capacity in mice
To test what they could do with a living cell, the researchers expressed zebrafish embryos with OptoSTIM1. After exposure to the blue light, the expressing cells showed signs of Ca2+ uptake while the others did not.
They next explored the idea of intercellular Ca2+ signaling. To do this, they tested human embryonic stem cells by exposing blue light to only a single cell in a colony which expressed OptoSTIM1. Despite only one cell being illuminated with blue light, they detected a Ca2+ delayed response in other, more distant and also non-illuminated cells indicating some level of intercellular communication.
Ca2+ release and uptake also plays an important role in brain cells and their functions, so the researchers explored Ca2+ modulation's effect on memory. The hippocampus controls memory so the scientists first tested cultured hippocampal cells expressing OptoSTIM1, and a Ca2+ influx was achieved when the cells were exposed to blue light.
Building on previous mice memory studies and their success with cultured hippocampal cells, they introduced OptoSTIM1 to the hippocampus of a living mouse. To test the functional effect of the Ca2+ influx, the IBS team compared sets of light-illuminated mice to non-illuminated mice expressing OptoSTIM1 in an environment where they introduced a conditioning cue followed by a fear stimulus. In subsequent tests they observed that light-illuminated mice with the OptoSTIM1 expression had a greater fear response when placed in the testing environment without the conditioning cue than the non-light-stimulated mice. In fact, they had a nearly twofold increase in fear stimulus response memory compared to non-light-stimulated mice, indicating that the OptoSTIM1 expression (and resultant Ca2+ uptake) was an effective method for memory enhancement.
Neurological enhancements and treatments
This work opens the door for future research into optogenetically enhanced memory and learning studies. More importantly, some neurological diseases which are a result of a dysfunction in Ca2+ regulation could be affected by optogenetically controlling the Ca2+ channels in the brain. This may also be a step towards discovering applications for drugs as well as therapeutic Ca2+ modulation. According to Kyung, "There are diseases that result from dysfunction in cellular Ca2+ regulation, such as Alzheimer's disease, so we can apply our system to those areas and hopefully in the near future help people to recover from those diseases." This may also allow for future non-invasive and non-drug treatments or may help to mitigate and eventually cure some neurological diseases.
Science Daily/SOURCE :http://www.sciencedaily.com/releases/2015/09/150914114635.htm
Scientists chart a lost highway in the brain
Computational neuroscientists contribute to effort to rediscover, map brain structure missing for over a century
September 14, 2015
Science Daily/Indiana University
A part of the brain lost from scientific literature for over a century may be responsible for a key component of perceptionm according to a new study from the neuroscientist who was part of the team that rediscovered the forgotten structure.
http://images.sciencedaily.com/2015/09/150914152718_1_540x360.jpg
Two 19th-century drawings of the VOF are from a post-mortem dissection. The right image was created by French anatomist Joseph Jules Déjerine in 1895.
Credit: Kevin Weiner
Recently, Indiana University computational neuroscientist Franco Pestilli and an international research team published an article in the journal Cerebral Cortex that suggests this missing part of the brain may play an important role in how we understand the world -- despite getting "lost" for more than a century.
A long flat bundle of nerves called the vertical occipital fasciculus, or VOF, the structure appeared in textbooks on the brain for about 30 years around the end of the 19th century, then mysteriously dropped out of sight completely. Pestilli was also part of the team that first traced this missing brain structure to an 1881 publication by Carl Wernicke, a German-Austrian neuroanatomist.
"Our new study shows that the VOF may provide the fundamental white matter connection between two parts of the visual system: that which identifies objects, words and faces and that which orients us in space," said Pestilli, senior author and assistant professor in the College of Arts and Sciences' Department of Psychological and Brain Sciences, whose work on the collaborative project began as a research associate at Stanford University.
"The structure forms a 'highway' between the lower, ventral part of the visual system, which processes the properties of faces, words and objects, and the upper, dorsal parietal regions, which orients attention to an object's spatial location," he added.
The first researcher on the paper was Hiromasa Takemura of the Center for Information and Neural Networks in Japan.
Based upon where the VOF terminates in the brain's cortex, Pestilli said the VOF might play a critical role in the brain's visual system, coordinating information transmission between brain areas important for "where we see" and "what we see."
In a long-standing debate, neuroscientists have argued the degree to which these two parts of the visual system function separately. The new study suggests that the regions work "hand-in-glove" to coordinate the body's movement in relation to people and objects around it.
There are "countless examples" that reflect how the two functions are intertwined, Pestilli said. Reaching for your keys, putting on your hat, driving to work each morning -- all require this what/where coordination. So does reading words on a page, which demands moving one's eyes with respect to the words and letters.
What happens when this "what/where" coordination fails? Pestilli points to the title character in the late neurologist and writer Oliver Sacks' "The Man Who Mistook His Wife for a Hat," who, when asked to get his hat and put it on, tries to pick up his wife's head to put it on his own.
In this strange disconnect between an object and its location, Sacks recognized the effect of a tumor or degeneration afflicting the patient's visual system. The problem may have specifically affected the functioning of the VOF, Pestilli said, speculating on the symptoms of Sacks' patient.
But how did an entire anatomical structure in the brain suddenly go missing in the first place? The answer may be scientific rivalry.
In their earlier paper, Pestilli and collaborators attributed the VOF's disappearance to competing beliefs among 19th-century neuroanatomists. In contrast to Wernicke, Theodor Meynert, another prominent scientist in Germany, never accepted the new structure due to his belief that all white matter pathways ran horizontally. Over time, the VOF faded into obscurity.
In addition to contributing to the rediscovery and function of the VOF, Pestilli's work is also helping map other parts of the human brain in unprecedented detail, using state-of-the-art neuroimaging and computational methods. This work will not only contribute to a deeper knowledge of the human brain -- such as how variations in brain structures relate to behavioral differences among individuals -- but will also strengthen the university's other investigations into complex networks, including brain connectivity, primarily within the recently established IU Network Science Institute.
"This new study really contributes to our understanding of how two important parts of the brain communicate," said Brian Wandell, a co-author at Stanford, "painting a picture of the brain that is highly interconnected."
Science Daily/SOURCE :http://www.sciencedaily.com/releases/2015/09/150914152718.htm
Learning in your sleep, the right way
October 28, 2015
Science Daily/Swiss National Science Foundation (SNSF)
You can swot up on vocabulary in your sleep, but only if you don’t confuse your brain in the process. Researchers have invited people to their sleep lab for a Dutch language course.
You can't learn new things in your sleep. Nevertheless, if you've been learning vocabulary in a foreign language, it can be highly effective to hear these words played over again while you sleep, as was already shown a year ago by researchers from the university of Zurich and Fribourg. Their new study, funded by the Swiss National Science Foundation, demonstrates that this only works if the brain can do its job undisturbed.
Translating doesn't help
The researchers got 27 German-speaking test subjects to learn Dutch words, then let them sleep for three hours in the sleep lab. The scientists already knew that playing back this vocabulary softly would help the test subjects to remember the words. Now they wanted to give them more information while they were asleep. The research team, led by biopsychologist Björn Rasch from the University of Fribourg, wanted to enhance the technique's impact by supplying German translations after the Dutch words. They also wanted to achieve the opposite -- in other words, they hoped that supplying incorrect translations would make the test subjects forget what they'd learned.
"To our surprise, we were neither able to enhance their memory, nor able to make them forget what they'd learned," says Rasch. He was able to confirm the original findings -- that simply cuing the Dutch vocabulary during sleep enabled the subjects to recall about ten percent more words. "But playing a second word right after the first seems to disrupt the relevant memory processes that had hitherto been activated," says Rasch. He and his team have concluded that it's not the total information offered to the brain that is important. Instead, the brain just needs a nudge in order to enhance the ability to recall.
Only in the lab -- for now
The results of this memory test were reflected in the brain wave patterns of the test subjects. While individual Dutch words were being played, the researchers recorded an enhancement in the waves characteristic of sleep and recollection (sleep spindles and theta-oscillation). But these activity patterns disappeared completely as soon as another word followed on from the first.
In a subsequent experiment, the researchers were also able to demonstrate that the time span between word pairs was of decisive importance. If the German translation followed only after 2 seconds instead of after 0.2 seconds, the disruptive effect disappeared. But there was still no enhancement of impact.
"For us, these results are further evidence that sleep promotes memory formation, with the brain spontaneously activating content that it had learnt beforehand. We were able to enhance this effect by playing back the words," says Rasch. It's as yet uncertain whether there will soon be an app to help people get better marks in their vocabulary tests. "Now we really want to get out of the controlled situation of the sleep lab, to see whether the impact we've observed can also be reproduced under z
Science Daily/SOURCE :http://www.sciencedaily.com/releases/2015/10/151028084925.htm