1. Study suggests cocoa and chocolate have benefits for cognition

    July 17, 2017 by Ashley

    From the Frontiers press release:

    A balanced diet is chocolate in both hands — a phrase commonly used to justify ones chocolate snacking behavior. A phrase now shown to actually harbor some truth, as the cocoa bean is a rich source of flavanols: a class of natural compounds that has neuroprotective effects.

    In their recent review published in Frontiers in Nutrition, Italian researchers examined the available literature for the effects of acute and chronic administration of cocoa flavanols on different cognitive domains. In other words: what happens to your brain up to a few hours after you eat cocoa flavanols, and what happens when you sustain such a cocoa flavanol enriched diet for a prolonged period of time?

    Although randomized controlled trials investigating the acute effect of cocoa flavanols are sparse, most of them point towards a beneficial effect on cognitive performance. Participants showed, among others, enhancements in working memory performance and improved visual information processing after having had cocoa flavanols. And for women, eating cocoa after a night of total sleep deprivation actually counteracted the cognitive impairment (i.e. less accuracy in performing tasks) that such a night brings about. Promising results for people that suffer from chronic sleep deprivation or work shifts.

    It has to be noted though, that the effects depended on the length and mental load of the used cognitive tests to measure the effect of acute cocoa consumption. In young and healthy adults, for example, a high demanding cognitive test was required to uncover the subtle immediate behavioral effects that cocoa flavanols have on this group.

    The effects of relatively long-term ingestion of cocoa flavanols (ranging from 5 days up to 3 months) has generally been investigated in elderly individuals. It turns out that for them cognitive performance was improved by a daily intake of cocoa flavanols. Factors such as attention, processing speed, working memory, and verbal fluency were greatly affected. These effects were, however, most pronounced in older adults with a starting memory decline or other mild cognitive impairments.

    And this was exactly the most unexpected and promising result according to authors Valentina Socci and Michele Ferrara from the University of L’Aquila in Italy. “This result suggests the potential of cocoa flavanols to protect cognition in vulnerable populations over time by improving cognitive performance. If you look at the underlying mechanism, the cocoa flavanols have beneficial effects for cardiovascular health and can increase cerebral blood volume in the dentate gyrus of the hippocampus. This structure is particularly affected by aging and therefore the potential source of age-related memory decline in humans.”

    So should cocoa become a dietary supplement to improve our cognition? “Regular intake of cocoa and chocolate could indeed provide beneficial effects on cognitive functioning over time. There are, however, potential side effects of eating cocoa and chocolate. Those are generally linked to the caloric value of chocolate, some inherent chemical compounds of the cocoa plant such as caffeine and theobromine, and a variety of additives we add to chocolate such as sugar or milk.”

    Nonetheless, the scientists are the first to put their results into practice: “Dark chocolate is a rich source of flavanols. So we always eat some dark chocolate. Every day.”


  2. Study suggests clever way to help de-clutter home

    July 14, 2017 by Ashley

    From the Ohio State University press release:

    If your attic is full of stuff you no longer use but can’t bear to give away, a new study may offer you a simple solution.

    Researchers found that people were more willing to give away unneeded goods that still had sentimental value if they were encouraged to take a photo of these items first, or find another way to preserve the memories.

    Such a strategy could help parents part with old baby clothes they no longer need or help a former athlete give up a favorite basketball or hockey stick.

    What people really don’t want to give up is the memories associated with the item,” said Rebecca Reczek, co-author of the study and associate professor of marketing at The Ohio State University’s Fisher College of Business.

    “We found that people are more willing to give up these possessions if we offer them a way to keep the memory and the identity associated with that memory.”

    Reczek conducted the study with Karen Winterich, associate professor of marketing at Pennsylvania State University, and Julie Irwin, professor of business at the University of Texas at Austin.

    The results were just published online in the Journal of Marketing.

    “The project got started when I realized I was keeping an old pair of basketball shorts just because they reminded me of beating a major rival basketball team in junior high,” Winterich said.

    “I didn’t want the shorts — I wanted the memory of winning that game and that’s what I thought of when I saw the shorts. A picture can easily mark that memory for me and I can donate it so someone else can use it, which is even better.”

    Inspired by this story, the researchers conducted a field study involving 797 students at Penn State who lived in six residence halls on campus. At the end of a fall semester, the researchers advertised a donation drive before the students left for the holidays. But there was a catch: There were actually two different advertising campaigns that varied by residence halls.

    In the memory preservation campaign, signs in the residence hall bathrooms stated, “Don’t Pack up Your Sentimental Clutter…Just Keep a Photo of It, Then Donate.” In the control campaign, fliers told students, “Don’t Pack Up Your Sentimental Clutter, Just Collect the Items, Then Donate.” Similar numbers of students were exposed to both campaigns.

    After finals week, research associates who were unaware of what the study was about emptied donation bins in each residence hall, counting the items donated.

    The researchers found 613 items were donated in the halls that hosted the “memory preservation” campaign, versus only 533 in the control campaign.

    Reczek said the results show it may be relatively easy to break our old habits of clinging to some of our possessions with sentimental value.

    “It is not terribly surprising that we can keep the same memories alive just by taking a photo of these possessions, but it is not a natural behavior. It is something we have to train ourselves to do,” she said.

    In other related experiments, the researchers found that it wasn’t just the memories associated with these possessions that were keeping people from donating — it was the identities linked to those memories.

    For example, older parents may still feel connected to their identity as new mothers and fathers and not want to part with their infant clothes.

    In one study, some people who were donating goods at a local thrift shop in State College, Pennsylvania, were given instant photos of the items they were donating, while others were not. They were then asked about whether they would feel a sense of identity loss from giving away the item.

    Results showed that those who received the photos reported less identity loss than those who did not.

    “These memories connected to possessions are a carrier for identity. It is this reluctance to give up a piece of our identity that is driving our reluctance to donate,” Reczek said.

    This memory preservation strategy won’t work for items that don’t have sentimental value, she said. It also won’t work for items you want to sell instead of donate. She also suspects there may be a limit to what some people are willing to give away.

    “It may not work for something that has a lot of sentimental value, like a wedding dress,” Reczek said.

    The bottom line is that everyone benefits by using this memory preservation strategy to de-clutter a home, Winterich said.

    “We hope that it will not only make it easier for people to clear out clutter, but it will also help spur the donation process, benefiting nonprofits and the recipients that they serve,” she said.


  3. Taking photos of experiences boosts visual memory, impairs auditory memory

    July 12, 2017 by Ashley

    From the Association for Psychological Science press release:

    A quick glance at any social media platform will tell you that people love taking photos of their experiences — whether they’re lying on the beach, touring a museum, or just waiting in line at the grocery store. New research shows that choosing to take photos may actually help us remember the visual details of our encounters.

    The findings are published in Psychological Science, a journal of the Association for Psychological Science.

    “Our research is novel because it shows that photo-taking itself improves memory for visual aspects of an experience but can hurt memory for nonvisual aspects, like auditory details,” the authors say.

    This research was conducted by Alixandra Barasch (New York University Stern School of Business), Kristin Diehl (USC Marshall School of Business), Jackie Silverman (The Wharton School of the University of Pennsylvania), and Gal Zauberman (Yale School of Management).

    Previous research has suggested that being able to take photographs or consult the Internet may allow us to outsource our memory, freeing up cognitive resources but potentially impairing our ability to remember.

    Barasch, Diehl, Silverman, and Zauberman hypothesized that this offloading effect may hold for factual information, but might not apply when it comes to the experiences we deliberately choose to photograph.

    “People take photos specifically to remember these experiences, whether it’s a fun dinner with friends, a sightseeing tour, or something else,” they argue.

    Of course, the reality is that most of the photos we take will probably never get a second glance. The researchers wondered: How well do we remember the experiences we photograph if we never revisit the photos? Furthermore, does taking photos affect memory for what we saw differently than for what we heard?

    In one experiment, the researchers had 294 participants tour a real-life museum exhibit of Etruscan artifacts. The participants stashed their belongings before starting the tour but some were allowed to keep a camera on them. Those with a camera could photograph anything they wanted in the exhibit and were told to take at least 10 photos. As the participants toured the exhibit, they listened to an accompanying audio guide.

    At the end of the tour, they answered multiple-choice questions asking them to identify objects they had seen or complete factual statements from the audio guide.

    The results showed that those who took photos visually recognized more of the objects compared with those who didn’t have a camera. But they also remembered less auditory information than their camera-less peers.

    These findings provided evidence that taking pictures can enhance visual memory. To test their hypotheses in a more controlled environment, the researchers designed a virtual art-gallery tour. Participants navigated through the gallery on screen as they would in real life and some were able to take pictures of what they saw on screen by clicking an on-screen button.

    Again, participants who were able to take pictures were better at recognizing what they saw and worse at remembering what they heard, compared to those who couldn’t take pictures.

    When the researchers examined visual memory for specific objects, they found that participants who were able to take pictures performed better on visual memory tasks regardless of whether the objects in question were the most or least photographed. Photo-takers even had better visual memory for aspects of the exhibit they didn’t photograph, compared with participants who weren’t able to take pictures.

    “These findings suggest that having a camera changes how people approach an experience in a fundamental way,” the authors say. “Even when people don’t take a photo of a particular object, like a sculpture, but have a camera with them and the intention to take photos, they remember that sculpture better than people who did not have a camera with them.”

    Pooling findings from all four studies, the researchers found that taking photos had a reliably positive effect on visual memory and a smaller but reliable negative effect on auditory memory.

    Even participants who thought their photos would be deleted and those who were instructed to “mentally take a photo” showed enhanced visual memory and impaired auditory memory relative to participants who couldn’t take pictures.

    Together, these experiments suggest that photographing our experiences doesn’t outsource our memory so much as it focuses it, funneling our attention toward visual aspects of our experiences and away from others.


  4. Snail study suggests select memories can be erased

    July 11, 2017 by Ashley

    From the Columbia University Medical Center press release:

    Different types of memories stored in the same neuron of the marine snail Aplysia can be selectively erased, according to a new study by researchers at Columbia University Medical Center (CUMC) and McGill University and published today in Current Biology.

    The findings suggest that it may be possible to develop drugs to delete memories that trigger anxiety and post-traumatic stress disorder (PTSD) without affecting other important memories of past events.

    During emotional or traumatic events, multiple memories can become encoded, including memories of any incidental information that is present when the event occurs. In the case of a traumatic experience, the incidental, or neutral, information can trigger anxiety attacks long after the event has occurred, say the researchers.

    “The example I like to give is, if you are walking in a high-crime area and you take a shortcut through a dark alley and get mugged, and then you happen to see a mailbox nearby, you might get really nervous when you want to mail something later on,” says Samuel Schacher, PhD, a professor of neuroscience in the Department of Psychiatry at CUMC and co-author of the paper. In the example, fear of dark alleys is an associative memory that provides important information — e.g., fear of dark alleys — based on a previous experience. Fear of mailboxes, however, is an incidental, non-associative memory that is not directly related to the traumatic event.

    “One focus of our current research is to develop strategies to eliminate problematic non-associative memories that may become stamped on the brain during a traumatic experience without harming associative memories, which can help people make informed decisions in the future — like not taking shortcuts through dark alleys in high-crime areas,” Dr. Schacher adds.

    Brains create long-term memories, in part, by increasing the strength of connections between neurons and maintaining those connections over time. Previous research suggested that increases in synaptic strength in creating associative and non-associative memories share common properties. This suggests that selectively eliminating non-associative synaptic memories would be impossible, because for any one neuron, a single mechanism would be responsible for maintaining all forms of synaptic memories.

    The new study tested that hypothesis by stimulating two sensory neurons connected to a single motor neuron of the marine snail Aplysia; one sensory neuron was stimulated to induce an associative memory and the other to induce a non-associative memory.

    By measuring the strength of each connection, the researchers found that the increase in the strength of each connection produced by the different stimuli was maintained by a different form of a Protein Kinase M (PKM) molecule (PKM Apl III for associative synaptic memory and PKM Apl I for non-associative). They found that each memory could be erased — without affecting the other — by blocking one of the PKM molecules.

    In addition, they found that specific synaptic memories may also be erased by blocking the function of distinct variants of other molecules that either help produce PKMs or protect them from breaking down.

    The researchers say that their results could be useful in understanding human memory because vertebrates have similar versions of the Aplysia PKM proteins that participate in the formation of long-term memories. In addition, the PKM-protecting protein KIBRA is expressed in humans, and mutations of this gene produce intellectual disability.

    “Memory erasure has the potential to alleviate PTSD and anxiety disorders by removing the non-associative memory that causes the maladaptive physiological response,” says Jiangyuan Hu, PhD, an associate research scientist in the Department of Psychiatry at CUMC and co-author of the paper. “By isolating the exact molecules that maintain non-associative memory, we may be able to develop drugs that can treat anxiety without affecting the patient’s normal memory of past events.”

    “Our study is a ‘proof of principle’ that presents an opportunity for developing strategies and perhaps therapies to address anxiety,” said Dr. Schacher. “For example, because memories are still likely to change immediately after recollection, a therapist may help to ‘rewrite’ a non-associative memory by administering a drug that inhibits the maintenance of non-associative memory.”

    Future studies in preclinical models are needed to better understand how PKMs are produced and localized at the synapse before researchers can determine which drugs may weaken non-associative memories.


  5. Brain-based memory recognition technology nearing use in court

    July 10, 2017 by Ashley

    From the University of Minnesota press release:

    In most crime scenes, there is some information that is known only by investigators and the actual perpetrator. Only the kidnapper knows what the abandoned shed where they kept a victim looks like, and only the true thief will know which house was burglarized. When confronted by investigators about this type of information, suspects uniformly answer: “I’ve never seen that before.” Soon, however, neuroscience technology may be able to help the legal system differentiate the truth tellers from the liars, according to a University of Minnesota study.

    The report, “The Limited Effect of Electroencephalography Memory Recognition Evidence on Assessments of Defendant Credibility,” published in the Journal of Law and the Biosciences, finds that brain-based memory recognition technology may be one step closer to court. The findings suggest American jurors can appropriately integrate the evidence in their evaluations of criminal defendants, which could ultimately lead to an additional expert witness on the stand.

    “The technology measures the electrical brain activity of defendants and witnesses, and should improve the legal system’s ability to determine who is telling the truth and who is not,” said Law Professor Francis Shen, the study’s lead author and director of the Neurolaw Lab, a unique collaborative at the University exploring the legal implications of neuroscience. “Our new interdisciplinary research is exciting because it’s some of the first to empirically test how this would work in practice.”

    Assessing the credibility of human memory is a central feature of the criminal justice system, from early stages of investigations to courtroom adjudication. For more than two decades, scientists and legal scholars have observed that brain-based memory recognition technology might have the potential to improve the justice system.

    The study includes results from multiple experiments examining the effect of neuroscientific evidence on subjects’ evaluation of a fictional criminal fact pattern, while manipulating the strength of the non-neuroscientific evidence. In two experiments, one using 868 online subjects and one using 611 in-person subjects, researchers asked subjects to read two short, fictional vignettes describing a protagonist accused of a crime.

    Manipulating expert evidence and the strength of the non-neuroscientific facts against the defendant, it was discovered that the neuroscientific evidence was not as powerful a predictor as the overall strength of the case in determining outcomes. The study concluded that subjects are cognizant of, but not seduced by, brain-based memory recognition evidence.

    “One day, it could become commonplace in justice investigations,” Shen said. “However, we need more studies like this and more collaboration across disciplines before we can be confident that this type of evidence should be used in real legal cases.”


  6. New technique isolates neuronal activity during memory consolidation

    July 7, 2017 by Ashley

    From the Spanish National Research Council (CSIC) press release:

    A team, led by researchers from the Cajal Institute (Madrid) belonging to the Spanish National Research Council (CSIC), have discovered some basic processes underlying memory consolidation in collaboration with colleagues at the National Hospital for Paraplegics in Toledo (Spain) and the University of Szeged (Hungary). The work, which is published in Neuron, identifies some of the electrical events responsible for specific neuronal activity in the hippocampus: a region of the brain with fundamental roles in episodic memory.

    In the study, highlighted at the front cover of the journal, researchers used machine learning to study brain electrical activity during memory reactivation. “Using artificial neural networks, we have been able to identify electrical fotprints associated to events with similar informational content, presumably encoding the same memory trace. Using sophisticated experimental techniques we have succeeded in isolating the activity of individual neurons during these ‘memories'” explains Liset Menéndez de la Prida, the Cajal Institute researcher who lead the work.

    As the researchers observed in their study, activity of hippocampal cells is precisely modulated during memory trace reactivation. “We have seen that most hippocampal cells acutely respond to ‘excitation’ and ‘inhibition’ as a kind of cellular yin-yang, in such a way that the participation of individual neurons of memory traces is extremely selective,” explains Manuel Valero, the first author of the paper.

    “Only those hippocampal neurons carrying information about a memory to be reactivated would receive more ‘excitation’ than ‘inhibition’ to be biased for a particular memory trace. This mechanism endows the hippocampus with the ability to reactivate individual memories without merging information.”

    In addition, researchers show that an imbalance between ‘excitation’ and ‘inhibition’ -characteristic of some brain diseases such as epilepsy – could be catastrophic for memories. “In epilepsy, we see a link between this mechanism and memory deficits. Our data suggest that alterations of excitation-inhibition balance not only contributes to epileptic activity, but also to the collapse of individual memory traces during consolidation, like an indissoluble mixture,” explains Menéndez de la Prida.

    The hippocampus, vital to generating memory

    As researchers point out, the function of hippocampus in memory was unveiled by the famous patient HM. “After he underwent bilateral surgical resection of both hippocampi for treating his epilepsy, he was unable to form new episodic memories.”

    Menéndez de la Prida explains that with the advancement of neuroscience, it has become increasingly clear that the hippocampus may play a dual role in memory formation. “First, it represents information concerning the time and place where you are at this moment, through sequences of neuronal activity that signal your location in the room and some other temporal contingencies”

    Valero adds, “Once this information is collected, it must be transformed into a long-term memory. This is carried out by the hippocampus through a process called consolidation. During consolidation, neuronal sequences already activated during experience are replayed several times at high speed. It is a process which expends a great deal of energy to leave an electrical footprint.” That footprint seems now to be more easily detected in the apparently noisy brain activity.


  7. Strategic studying limits the costs of divided attention

    July 6, 2017 by Ashley

    From the Association for Psychological Science press release:

    Multitasking while studying may impair overall memory for the study material, but your ability to strategically identify and remember the most important information may stay intact, according to new findings published in Psychological Science, a journal of the Association for Psychological Science.

    “Dividing attention wasn’t necessarily a good thing for learning and recall, but we found that distracted participants were just as likely to recall the most important information as were participants who were able to give the presented information their full attention,” explains psychology researcher Catherine D. Middlebrooks of the University of California, Los Angeles. “The ability to prioritize high-value information during study was consistently immune to the effects of divided attention, regardless of the extent of the distractions that participants faced.”

    Previous research has shown that learners are able to compensate for the limitations of memory by prioritizing certain information and essentially sacrificing other information as they study. That is, they strategically compensate for factors that are beyond their control — but deploying this strategic approach to studying itself requires cognitive resources. Middlebrooks and UCLA co-authors Tyson K. Kerr and Alan D. Castel wanted to know whether learners have sufficient cognitive resources to overcome the potential costs incurred by studying strategically.

    In one experiment, the researchers asked 192 undergraduate student participants to view a series of word lists and remember as many words as possible. Importantly, each word had a numerical value, from 1 to 10, and participants were instructed to maximize the total value of the words they recalled.

    Students randomly assigned to the divided attention group studied the word lists as digits were also being read aloud — they were instructed to press a key every time they heard three odd digits in a row. Other students studied the lists while lyrical music, with which they were familiar or unfamiliar, played in the background. Another group of students studied with no additional distractions.

    As expected, those students who were forced to divide their attention between the word list and the digits recalled fewer words compared with the students in the other groups. The data showed that the background music had no discernible effect on students’ overall recall.

    Importantly, students really did seem to pay attention to the value of the words — their odds of recalling a 10-point word were almost five times greater than their odds of recalling a 1-point word. The link between value and recall held for students in all of the groups, regardless of whether they studied with or without distraction.

    The findings suggest that the students adjusted their studying to compensate for their study conditions, paying particular attention to the most important study items.

    A second experiment, in which students had to divide their attention between studying word lists and completing tone-monitoring tasks that varied in difficulty, showed a similar pattern of results. Participants performed worse when their attention was divided, but they were still able to selectively remember the high-value words.

    In both experiments, participants were better able to remember the words as they gained more experience with the task, suggesting that their ability to study selectively improved with practice.

    “Situations in which we can actually give something our full, truly undivided attention are often few and far between — at any given moment, you’re likely to be distracted to some extent by a number of factors,” says Middlebrooks. “Our findings don’t suggest that multi-tasking or being distracted will never affect how well we might prioritize important information, but they do suggest that distraction does not automatically doom our efforts and that we seem to consider their costs when deciding how best to allocate our limited resources.”

    In future research, Middlebrooks and colleagues hope to explore how various real-world factors — such as having to choose which material to study and how — might affect strategic studying.


  8. Extra-virgin olive oil preserves memory, protects brain against Alzheimer’s

    July 4, 2017 by Ashley

    From the Temple University Health System press release:

    The Mediterranean diet, rich in plant-based foods, is associated with a variety of health benefits, including a lower incidence of dementia. Now, researchers at the Lewis Katz School of Medicine at Temple University (LKSOM) have identified a specific ingredient that protects against cognitive decline: extra-virgin olive oil, a major component of the Mediterranean diet. In a study published online June 21 in the Annals of Clinical and Translational Neurology, the researchers show that the consumption of extra-virgin olive oil protects memory and learning ability and reduces the formation of amyloid-beta plaques and neurofibrillary tangles in the brain — classic markers of Alzheimer’s disease.

    The Temple team also identified the mechanisms underlying the protective effects of extra-virgin olive oil. “We found that olive oil reduces brain inflammation but most importantly activates a process known as autophagy,” explained senior investigator Domenico Praticò, MD, Professor in the Departments of Pharmacology and Microbiology and the Center for Translational Medicine at LKSOM. Autophagy is the process by which cells break down and clear out intracellular debris and toxins, such as amyloid plaques and tau tangles.

    “Brain cells from mice fed diets enriched with extra-virgin olive oil had higher levels of autophagy and reduced levels of amyloid plaques and phosphorylated tau,” Dr. Praticò said. The latter substance, phosphorylated tau, is responsible for neurofibrillary tangles, which are suspected of contributing to the nerve cell dysfunction in the brain that is responsible for Alzheimer’s memory symptoms.

    Previous studies have suggested that the widespread use of extra-virgin olive oil in the diets of people living in the Mediterranean areas is largely responsible for the many health benefits linked to the Mediterranean diet. “The thinking is that extra-virgin olive oil is better than fruits and vegetables alone, and as a monounsaturated vegetable fat it is healthier than saturated animal fats,” according to Dr. Praticò.

    In order to investigate the relationship between extra-virgin olive oil and dementia, Dr. Praticò and colleagues used a well-established Alzheimer’s disease mouse model. Known as a triple transgenic model, the animals develop three key characteristics of the disease: memory impairment, amyloid plagues, and neurofibrillary tangles.

    The researchers divided the animals into two groups, one that received a chow diet enriched with extra-virgin olive oil and one that received the regular chow diet without it. The olive oil was introduced into the diet when the mice were six months old, before symptoms of Alzheimer’s disease begin to emerge in the animal model.

    In overall appearance, there was no difference between the two groups of animals. However, at age 9 months and 12 months, mice on the extra virgin olive oil-enriched diet performed significantly better on tests designed to evaluate working memory, spatial memory, and learning abilities.

    Studies of brain tissue from both groups of mice revealed dramatic differences in nerve cell appearance and function.

    “One thing that stood out immediately was synaptic integrity,” Dr. Praticò said. The integrity of the connections between neurons, known as synapses, were preserved in animals on the extra-virgin olive oil diet. In addition, compared to mice on a regular diet, brain cells from animals in the olive oil group showed a dramatic increase in nerve cell autophagy activation, which was ultimately responsible for the reduction in levels of amyloid plaques and phosphorylated tau.

    “This is an exciting finding for us,” explained Dr. Praticò. “Thanks to the autophagy activation, memory and synaptic integrity were preserved, and the pathological effects in animals otherwise destined to develop Alzheimer’s disease were significantly reduced. This is a very important discovery, since we suspect that a reduction in autophagy marks the beginning of Alzheimer’s disease.”

    Dr. Praticò and colleagues plan next to investigate the effects of introducing extra-virgin olive oil into the diet of the same mice at 12 months of age, when they have already developed plaques and tangles. “Usually when a patient sees a doctor for suspected symptoms of dementia, the disease is already present,” Dr. Praticò added. “We want to know whether olive oil added at a later time point in the diet can stop or reverse the disease.”


  9. Mapping how words leap from brain to tongue

    July 3, 2017 by Ashley

    From the San Diego State University press release:

    When you look at a picture of a mug, the neurons that store your memory of what a mug is begin firing. But it’s not a pinpoint process; a host of neurons that code for related ideas and items — bowl, coffee, spoon, plate, breakfast — are activated as well. How your brain narrows down this smorgasbord of related concepts to the one word you’re truly seeking is a complicated and poorly understood cognitive task. A new study led by San Diego State University neuroscientist Stephanie Ries, of the School of Speech, Language, and Hearing Sciences, delved into this question by measuring the brain’s cortical activity and found that wide, overlapping swaths of the brain work in parallel to retrieve the correct word from memory.

    Most adults can quickly and effortlessly recall as many as 100,000 regularly used words when prompted, but how the brain accomplishes this has long boggled scientists. How does the brain nearly always find the needle in the haystack? Previous work has revealed that the brain organizes ideas and words into semantically related clusters. When trying to recall a specific word, the brain activates its cluster, significantly reducing the size of the haystack.

    To figure out what happens next in that process, Ries and colleagues asked for help from a population of people in a unique position to lend their brainpower to the problem: patients undergoing brain surgery to reduce their epileptic seizures. Before surgery, neurosurgeons monitor their brain activity to figure out which region of the brain is triggering the patients’ seizures, which requires the patients to wear a grid of dozens of electrodes placed directly on top of the cortex, the outermost folded layers of the brain.

    While the patients were hooked up to this grid in a hospital and waiting for a seizure to occur, Ries asked if they’d be willing to participate in her research. Recording brain signals directly from the cortical surface affords neuroscientists like Ries an unparalleled look at exactly when and where neurons are communicating with one another during tasks.

    “During that period, you have time to do cognitive research that’s impossible to do otherwise,” she said. “It’s an extraordinary window of opportunity.”

    For the recent study, nine patients agreed to participate. In 15 minute-sessions, she and her team would show the patients an item on a computer screen — musical instruments, vehicles, houses — then ask them to name it as quickly as possible, all while tracking their brain activity.

    They measured the separate neuronal processes involved with first activating the item’s conceptual cluster, then selecting the proper word. Surprisingly, they discovered the two processes actually happen at the same time and activate a much wider network of brain regions than previously suspected. As expected, two regions known to be involved in language processing lit up, the left inferior frontal gyrus and the posterior temporal cortex. But so did several other regions not traditionally linked to language, including the medial and middle frontal gyri, the researchers reported in the Proceedings of the National Academy of Sciences.

    “This work shows the word retrieval process in the brain is not at all as localized as we previously thought,” Ries said. “It’s not a clear division of labor between brain regions. It’s a much more complex process.”

    Learning exactly how the brain accomplishes these tasks could one day help speech-language pathologists devise strategies for treating disorders that prevent people from readily accessing their vocabulary.

    “Word retrieval is usually effortless in most people, but it is routinely compromised in patients who suffer from anomia, or word retrieval difficulty,” Ries said. “Anomia is the most common complaint in patients with stroke-induced aphasia, but is also common in neurodegenerative diseases and normal aging. So it is critical to understand how this process works to understand how to help make it better.”


  10. Poor adolescent diet may influence brain and behavior in adulthood

    July 2, 2017 by Ashley

    From the Society for Neuroscience press release:

    Adolescent male mice fed a diet lacking omega-3 fatty acids show increased anxiety-like behavior and worse performance on a memory task in adulthood, according to new research published in The Journal of Neuroscience. The study suggests adequate nutrition in adolescence is important for the refinement of the adult brain and behavior.

    The structure and function of the brain continue to change throughout adolescence, at the same time that teenagers gain increasing independence and begin to make their own food choices. Since high-calorie, low-quality diets tend to be more affordable than healthy ones, teenagers may opt for foods that lack key nutrients important for brain health such as omega-3 polyunsaturated fatty acids (n-3 PUFAs), which cannot be produced by the human body and must be obtained from foods such as fish and vegetables.

    Oliver Manzoni and colleagues fed mice a balanced diet until early adolescence, when some mice were switched to a diet lacking n-3 PUFAs. Mice fed the poor diet during adolescence had reduced levels of n-3 PUFA in the medial prefrontal cortex and the nucleus accumbens in adulthood compared to control mice. The low-quality diet impaired the brain’s ability to fine-tune connections between neurons in these regions.