Forgetting can make you smarter

For most people having a good memory means being able to remember more information clearly for long periods of time. For neuroscientists too, the inability to remember was long believed to represent a failure of the brain’s mechanisms for storing and retrieving information.

But according to a new review paper from Paul Frankland, a senior fellow in CIFAR’s Child & Brain Development program, and Blake Richards, an associate fellow in the Learning in Machines & Brains program, our brains are actively working to forget. In fact, the two University of Toronto researchers propose that the goal of memory is not to transmit the most accurate information over time, but to guide and optimize intelligent decision making by only holding on to valuable information.

“It’s important that the brain forgets irrelevant details and instead focuses on the stuff that’s going to help make decisions in the real world,” says Richards.

The review paper, published this week in the journal Neuron, looks at the literature on remembering, known as persistence, and the newer body of research on forgetting, or transience. The recent increase in research into the brain mechanisms that promote forgetting is revealing that forgetting is just as important a component of our memory system as remembering.

“We find plenty of evidence from recent research that there are mechanisms that promote memory loss, and that these are distinct from those involved in storing information,” says Frankland.

One of these mechanisms is the weakening or elimination of synaptic connections between neurons in which memories are encoded. Another mechanism, supported by evidence from Frankland’s own lab, is the generation of new neurons from stem cells. As new neurons integrate into the hippocampus, the new connections remodel hippocampal circuits and overwrite memories stored in those circuits, making them harder to access. This may explain why children, whose hippocampi are producing more new neurons, forget so much information.

It may seem counterintuitive that the brain would expend so much energy creating new neurons at the detriment of memory. Richards, whose research applies artificial intelligence (AI) theories to understanding the brain, looked to principles of learning from AI for answers. Using these principles, Frankland and Richards frame an argument that the interaction between remembering and forgetting in the human brain allows us to make more intelligent memory-based decisions.

It does so in two ways. First, forgetting allows us to adapt to new situations by letting go of outdated and potentially misleading information that can no longer help us maneuver changing environments.

“If you’re trying to navigate the world and your brain is constantly bringing up multiple conflicting memories, that makes it harder for you to make an informed decision,” says Richards.

The second way forgetting facilitates decision making is by allowing us to generalize past events to new ones. In artificial intelligence this principle is called regularization and it works by creating simple computer models that prioritize core information but eliminate specific details, allowing for wider application.

Memories in the brain work in a similar way. When we only remember the gist of an encounter as opposed to every detail, this controlled forgetting of insignificant details creates simple memories which are more effective at predicting new experiences.

Ultimately, these mechanisms are cued by the environment we are in. A constantly changing environment may require that we remember less. For example, a cashier who meets many new people every day will only remember the names of her customers for a short period of time, whereas a designer that meets with her clients regularly will retain that information longer.

“One of the things that distinguishes an environment where you’re going to want to remember stuff versus an environment where you want to forget stuff is this question of how consistent the environment is and how likely things are to come back into your life, ” says Richards.

Similarly, research shows that episodic memories of things that happen to us are forgotten more quickly than general knowledge that we access on a daily basis, supporting the old adage that if you don’t use it, you lose it. But in the context of making better memory-based decisions, you may be better off for it.

 

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

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.”

 

New approach to teaching music improvisation enhances creativity

As World Music Day is approaching, taking place each year on 21 June, many are looking forward to the musical events in the streets or parks and the atmosphere it brings with it. Watching musicians perform can be impressive, even more so when they improvise. The performers produce their works in real-time and while improvising, they manage several processes simultaneously including generating melodic and rhythmic sequences, coordinating performance with other musicians in an ensemble and evaluating internal and external stimuli. All this is done with the overall goal of creating aesthetically appealing music. It keeps some of us wondering, how they do it and whether this can be learned at all.

In fact, improvisation is being taught in music education and often focuses on the development of techniques. Dr Michele Biasutti, Associate Professor at the University of Padua in Italy however examined how to go beyond these current practices in his recent paper “Pedagogical applications of cognitive research on musical improvisation.” Based on a literature review, the aim was to develop a model that looks at developing processes for improvisation that enhance creativity.

“Practices such as playing by ear is underexposed in current teaching approaches, which stress notated instruction and exercises such as scales and chords. Instead, I propose an approach that is based on the development of cognitive processes that enhance creativity and the abilities of the players to reflect on their performance skills,” states Biasutti.

Improvisation is a complex and multidimensional act that involves creativity and performance behaviours in real-time. It also requires processes such as sensory and perceptual encoding, motor control and performance monitoring as well as storing and recalling memory.

“A teaching approach based on the development of processes could be beneficial in music improvisation at several levels. A process-oriented teaching method can provide inputs for developing specific skills such as problem solving and critical thinking to assist the reflective practice during improvisation. The target processes were the following: anticipation, use of repertoire, emotive communication, feedback and flow,” explains Biasutti.

This process approach encourages students to think about their creative processes and to self-assess their experiences, thus developing a more complete awareness about the activities performed. In the past, teaching and learning consisted of information being passed-on, memorised and repeated. Now, students have to increasingly find their own knowledge by using information in creative ways, which requires a shift in how students are taught. The paper suggests that this could be achieved by teaching improvisation abilities, whereby teachers become more of facilitators who shift the focus from the evaluation of learning outcomes to the quality of processes that lead to improvisational expertise.

Biasutti concludes “There are several educational benefits to developing improvisational skills also for other disciplines. Improvisation could be considered an adaptive behaviour to a real-time unpredicted event. The response can be shaped through creativity and the divergent skillset that improvisation fosters. Improvisation could become a teaching technique to be used in educational contexts. Promoting improvisational skills would allow the students to develop the ability to adapt to tomorrow’s changing world, providing tools for lifelong learning.”

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Mapping how words leap from brain to tongue

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.”

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Why the ‘peculiar’ stands out in our memory

Memories that stick with us for a lifetime are those that fit in with a lot of other things we remember — but have a slightly weird twist.

It’s this notion of ‘peculiarity’ that can help us understand what makes lasting memories, according to Per Sederberg, a professor of psychology at The Ohio State University.

“You have to build a memory on the scaffolding of what you already know, but then you have to violate the expectations somewhat. It has to be a little bit weird,” Sederberg said.

Sederberg talked about the neuroscience of memory as an invited speaker at the Cannes Lions Festival of Creativity in France on June 19. He spoke at the session “What are memories made of? Stirring emotions and last impressions” along with several advertising professionals and artists.

Sederberg has spent his career studying memory. In one of his most notable studies, he had college students wear a smartphone around their neck with an app that took random photos for a month. Later, the participants relived memories related to those photos in an fMRI scanner so that Sederberg and his colleagues could see where and how the brain stored the time and place of those memories.

From his own research and that of others, Sederberg has ideas on which memories stick with us and which ones fade over time.

The way to create a long-lasting memory is to form an association with other memories, he said.

“If we want to be able to retrieve a memory later, you want to build a rich web. It should connect to other memories in multiple ways, so there are many ways for our mind to get back to it.”

A memory of a lifetime is like a big city, with many roads that lead there. We forget memories that are desert towns, with only one road in. “You want to have a lot of different ways to get to any individual memory,” Sederberg said.

The difficulty is how to best navigate the push and pull between novelty and familiarity. Novelty tells us what is important to remember. On the other hand, familiarity tells us what we can ignore, but helps us retrieve information later, Sederberg said.

Too much novelty, and you have no way to place it in your cognitive map, but too much familiarity and the information is similarly lost.

What that means is that context and prediction play critical roles in shaping our perception and memory. The most memorable experiences are those that arise in a familiar and stable context, yet violate some aspect of what we predict would occur in that context, he said.

“Those peculiar experiences are the things that stand out, that make a more lasting memory.”

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Materials provided by Ohio State University. Original written by Jeff Grabmeier. Note: Content may be edited for style and length.

More brain activity is not always better when it comes to memory, attention

Potential new ways of understanding the cause of cognitive impairments, such as problems with memory and attention, in brain disorders including schizophrenia and Alzheimer’s are under the spotlight in a new research review.

The review has just been published in a special ‘Pharmacology of Cognition’ issue of the British Journal of Pharmacology. In the paper, Tobias Bast, Stephanie McGarrity and Marie Pezze from the School of Psychology at The University of Nottingham highlight recent evidence, which suggests that too much uncontrolled activity in specific brain areas may lead to the cognitive impairments characterizing these conditions.

Neurons in the brain interact by sending each other chemical messages, so-called neurotransmitters. Gamma-aminobutyric acid (GABA) is the most common inhibitory neurotransmitter, which is important to restrain neural activity, preventing neurons from getting too trigger-happy and from firing too much or responding to irrelevant stimuli. In the extreme, impaired inhibitory GABA transmission can cause epileptic seizures. In addition, as highlighted in the review, more subtle impairments in inhibitory GABA transmission, which are below the threshold to cause seizures, have recently been linked to a range of brain disorders characterised by cognitive impairments, including schizophrenia, age-related cognitive decline and early stages of Alzheimer’s. However, until recently it was not clear if and how such subtle impairments in inhibitory GABA function affect important cognitive functions, such as memory and attention.

Two recent studies by Dr Bast and his colleagues have combined experimental reductions in inhibitory GABA transmission in specific brain regions with behavioural tests of memory and attention in rats.These studies focused on two brain regions that have long been known to be important for memory and attention, the prefrontal cortex and the hippocampus (a brain region in the temporal lobe). The studies found that faulty inhibitory neurotransmission and abnormally increased activity in the prefrontal cortex or hippocampus impairs memory and attention.

Dr Bast said: “Traditionally, memory and attentional impairments in conditions like aging, Alzheimer’s disease and schizophrenia have mainly been thought to be caused by reduced neural activity or damage in brain regions such as the prefrontal cortex or hippocampus. However, more recent evidence shows that actually too much activity can be just as detrimental for memory and attention.

We reviewed recent studies in animal models, including our own research, which show that some important cognitive functions, including memory and attention, can be impaired if neural activity in brain regions, including the prefrontal cortex and hippocampus, is not under sufficient inhibitory control, which is normally mediated by the inhibitory neurotransmitter GABA.

A key finding is that increased activity of a brain region, due to faulty inhibitory neurotransmission, can be more detrimental to cognitive function than reduced activity or a lesion. Insufficiently restrained activity within a brain region can disrupt not only the function of the region itself, but also the function of other regions to which it is connected. For example, our studies revealed that faulty inhibitory neurotransmission in the hippocampus does not only disrupt aspects of memory typically supported by this brain region, but also impaired attentional function, which is highly dependent on the prefrontal cortex, a region that is strongly connected to the hippocampus.

We hope that our findings and a deeper understanding of the brain mechanisms underlying impairments in memory and attention will help to develop new treatments for these debilitating problems. Our review highlights potential pharmacological treatments to re-balance aberrant neural activity and restore memory and attention, which we aim to test in future research.”

The review is part of a special issue concerned with the Pharmacology of Cognition, on the British journal of Pharmcology which is co-edited by Dr Paula Moran, Associate Professor and Reader in Behavioural Neuroscience at the University of Nottingham. She explains the significance of this issue for understanding cognitive conditions: “We urgently need new strategies to treat cognitive problems.These problems occur not only in Alzhiemer’s disease and aging, but also in psychiatric disorders such as schizophrenia, depression and anxiety. It is often overlooked, but the functional outcomes of these disorders can depend on how well people can learn, remember and concentrate. New treatments are most likely to come from deeper understanding of brain circuitries that are involved. This special issue adresses new approaches to improving cognition from rebalancing abnormal neural activity to cannabinoids to exercise. It also highlights the importance of not only using information from animal models to translate to human studies but also taking that information back to animal models to improve their accuracy to to predict new treatments.”

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More amyloid in the brain, more cognitive decline

A new study from the Center for Vital Longevity at The University of Texas at Dallas has found that the amount of amyloid plaques in a person’s brain predicts the rate at which his or her cognition will decline in the next four years.

The study, published in JAMA Neurology, used positron emission tomography (PET) scans to detect amyloid in 184 healthy middle-age and older adults participating in the Dallas Lifespan Brain Study. Amyloid plaques, a sticky buildup that gradually gathers outside of neurons and is a hallmark of Alzheimer’s disease, are believed to start accumulating in the brain 10 to 20 years before the onset of dementia.

“We think it is critical to examine middle-age adults to detect the earliest possible signs of Alzheimer’s disease, because it is becoming increasingly clear that early intervention is the key to successful prevention of Alzheimer’s disease,” said Michelle Farrell, a PhD student at the center and the lead author of the study.

The study presents some of the first data on amyloid and its cognitive consequences in adults ages 40 to 59. For these middle-age adults, the study found that higher amyloid amounts were associated with declines in vocabulary, an area of cognition that is generally preserved as people age.

The results suggest that a new approach might be needed to provide physicians and patients with information about the future for someone with amyloid deposits. Amyloid PET scan results are typically presented as either positive or negative, but the new findings suggest that the amount of amyloid in the brain provides useful prognostic information about how rapidly cognition may decline in the future.

“Our understanding of the earliest and silent phase of possible Alzheimer’s disease is increasing rapidly. Providing physicians and patients with more information about the magnitude of amyloid deposits will provide valuable information that will permit better planning for the future,” said Dr. Denise Park, director of research at the Center for Vital Longevity, Distinguished University Chair in Behavioral and Brain Sciences and senior author of the study.

Park heads up the Dallas Lifespan Brain Study, which is a multi-year research project aimed at understanding what a healthy brain looks like and how it functions at every decade of life from age 20 through 90. Each of the nearly 500 volunteers in the study undergo tests every four years.

While most studies of amyloid and its relationship to Alzheimer’s disease have focused on older adults over age 60, the Dallas Lifespan Brain Study also studies middle-age adults to find the earliest possible signs of Alzheimer’s disease.

In the JAMA Neurology research, the three middle-age adults who had the highest amyloid amounts and greatest vocabulary decline were also found to have a double dose of the ApoE-4 gene implicated in Alzheimer’s. This means they received a copy of the gene from each of their parents. Only about 4 percent of the population carries this genetic combination, and the finding hints at the possibility that subtle symptoms of cognitive decline related to amyloid may be detectable as early as middle age in this vulnerable population.

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Concussion effects detailed on microscopic level

New research has uncovered details about subcellular-level changes in the brain after concussion that could one day lead to improved treatment.

Researchers at The Ohio State University examined the effects of laboratory-induced mild traumatic brain injury on rodent brain tissue and found rapid microscopic swelling along the axons — the long and slender part of the nerve cell that sends vital messages to other parts of the brain. Similar swellings are seen in the brains of people with Alzheimer’s disease or Parkinson’s disease.

“We think based on our study in an animal model and in the lab that it’s highly likely that when a person has a concussion some of the neurons swell within a few seconds, much more rapidly than we expected,” said study author Chen Gu, an associate professor of biological chemistry and pharmacology.

The good news: These swollen spots along the axons are reversible, Gu and his collaborators found. Their study appears in the Journal of Cell Biology.

“When we stop the mechanical stress, the swelling actually disappears within minutes and the axon can recover. This is critical, because the axon is where important signals happen — for our senses, motor skills, cognition, emotion and all kinds of neurophysiological functions,” he said.

“This is probably highly relevant to mild traumatic brain injury, or concussion, and corresponds to what is seen in the clinic — that most people recover fully with time.”

The researchers also discovered a likely mechanism for the swelling, which could be important information for those looking to prevent, treat and better understand concussions in people.

The stress applied to brain tissue in the lab was designed to mimic a blow to the head. The researchers hit the tissue with blasts of liquid delivered through a pipette — a method they called “puffing.”

And that stress activated a protein called TRPV4, which causes a chain reaction that prompts a pause in content exchange along the axon.

“It’s like having a highway with a lot of cargo running in both directions. After the concussion, the highway closes and there’s a major traffic jam,” Gu said. “If the stress to the brain stops, the highway opens back up and the cargo slowly starts to move again.”

When Gu and his colleagues suppressed TRPV4 in the lab, swelling did not happen.

It remains unclear how exactly this plays out in humans, and the degree to which people may respond differently to blows to the head and other neurological problems, Gu said.

“In some cases, for example Alzheimer’s disease, there may be irreversible changes — where the axon is broken,” he said.

“We are trying to better understand the difference between reversible damage and irreversible damage and if we can gain a better understanding of this, it could help with development of new treatment strategies.”

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Concentration spans drop when online ads pop up

Two Polish researchers have shown that measurements of the brain’s electrical activity can be used to test the influence of intrusive online advertisements on internet users’ concentration and emotions. The exploratory study was conducted by Izabela Rejer and Jaroslaw Jankowski of the West Pomeranian University of Technology in Poland, and is published in Springer’s journal Cognitive Processing.

Rejer and Jankowski’s direct, objective and real-time approach extends current research about the effect of intrusive marketing on internet users. So far, most studies on this topic have been subjective in nature, and have typically analysed only the impact of online advertisements on brand awareness and memory. Other researchers have investigated web users’ visual attention, recorded their behaviour, or relied heavily on subjective information provided in questionnaires.

In Rejer and Jankowski’s experiment five Polish men and one woman, between 20 and 25 years years of age, were instructed to read ten short pages of text on a computer screen, after which they had to answer questions about the content. During the reading process, their attention was distracted when online advertisements randomly appeared on screen. The brain activity of each participant was measured using an electroencephalogram (EEG). The researchers did not only take note of each participant’s brain signal patterns, but also analysed how consistent these were across the different trials, and how they correlated with those of others.

Two main effects were observed for most subjects. First, the presence of online advertisements influenced participants’ concentration. This was deduced from the significant drop in beta activity that was observed in the frontal/prefrontal cortical areas. According to the researchers, this could indicate that the presentation of the advertisement induced a drop in concentration levels.

Secondly, the appearance of the advertisement induced changes in the frontal/prefrontal asymmetry index. However, the direction of this change differed among subjects, in that for some it dipped, and for others it increased.

The researchers believe that the participants’ response to the advertisement might be influenced by their so-called motivation predisposition. “If the subject is more ‘approach’ oriented, the changes in the asymmetry index might reflect growing activity in the left brain hemisphere. If, on the other hand, the subject is more ‘withdraw’ oriented, these changes might reflect the growing activity in the right hemisphere,” explains Rejer, who also notes that this is only a hypothesis that should be tested in future work on the intrusive nature of different forms of online advertisements.

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Acting and thinking: Are they the same for our brain?

Our brain’s fronto-parietal network is responsible for a range of highly diverse functions, from planning and executing movements to mental rotation, and from spatial attention to working memory. But how can a single network participate in such a wide variety of functions? Neuroscientists from the University of Geneva (UNIGE) and the University Hospitals of Geneva (HUG), Switzerland, have recently put forward an original hypothesis — all these cognitive functions rely on one central function: emulation.

This function creates an abstract dynamic ‘image’ of movements, thereby enabling the brain to strengthen its motor skills and construct a precise and lasting representation of them. The fronto-parietal network, it is argued, has evolved from a network that only controlled motor skills to a much more generalised system. This hypothesis, which is set out in the journal Trends in Cognitive Sciences, would explain why patients who have suffered an injury in this specific part in the brain have sequelae that affect a number of functions which, at first glance, do not necessarily appear to be linked. This research could open the door to more effective multi-modal therapies for individuals with cerebral lesions.

Numerous functional imaging studies show that the fronto-parietal network is activated by very disparate tasks. This is the case for motor activities, such as picking up or pointing to an object, as well as for eye movements — and even when no movement is involved, if we shift our attention or perform a mental calculation. Radek Ptak, a neuropsychologist at the UNIGE Faculty of medicine and the HUG Division of neurorehabilitation, puts it like this: “Why is the very same region important for so many different tasks? What is the relationship between motor skills, motor learning and the development of cognition in humans? These are the questions that lie at the heart of our research.” A review of all the data currently available suggests that the tasks share a common process, which the scientists have termed “emulation.” This process, which consists of planning and representing a movement without actually performing it, activates the brain network in the same way as real movements. “But we hypothesise that the brain goes a step further,” explains Dr Ptak: “It uses such dynamic representations to carry out increasingly complex cognitive functions beyond just planning movements.”

Imagining as a form of treatment

The close link between motor planning and higher cognitive functions is illustrated in infant development: a baby learns to represent the environment by manipulating objects. Conversely, the skier who mentally rehearses his race before starting improves his performance. Such anticipated action prepares him for movements that are more accurate and precise.

The same principle also explains why people with lesions in the fronto-parietal network have difficulty performing motor as well as cognitive tasks. Such correlations explain why the rehabilitation of impaired motor functions may benefit from cognitive interventions. For example, mirrors can be used with hemiplegic individuals to prompt the brain to believe that the paretic hand is still working perfectly. Though this technique uses a perceptual deception (since we actually look at the reflection of the functional hand), it helps regain lost motor capacities. In a similar vein, virtual reality makes it possible to dissociate perception and motor or sensory function, and is therefore a tool that scientists in Geneva are employing more and more often. Nevertheless, Radek Ptak remains cautious: “We need to continue our research so that we can provide robust data on how effective these techniques are. But, although this approach is new, it already has a big advantage: patients like it and happily follow this treatment. Their motivation can only be positive on the outcome of the therapy!”

The emulation hypothesis outlined above, which is based on numerous observations, opens up interesting perspectives. In addition to therapeutic possibilities, it raises more general questions about the origins of human cognition. If the principle of emulation has made it possible to expand the functions of a network that initially specialised in managing motor skills, to what extent can cognition be transformed even further? This is a debate that is likely to perdure.

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Simple tasks don’t test brain’s true complexity

The human brain naturally makes its best guess when making a decision, and studying those guesses can be very revealing about the brain’s inner workings. But neuroscientists at Rice University and Baylor College of Medicine said a full understanding of the complexity of the human brain will require new research strategies that better simulate real-world conditions.

Xaq Pitkow and Dora Angelaki, both faculty members in Baylor’s Department of Neuroscience and Rice’s Department of Electrical and Computer Engineering, said the brain’s ability to perform “approximate probabilistic inference” cannot be truly studied with simple tasks that are “ill-suited to expose the inferential computations that make the brain special.”

A new article by the researchers suggests the brain uses nonlinear message-passing between connected, redundant populations of neurons that draw upon a probabilistic model of the world. That model, coarsely passed down via evolution and refined through learning, simplifies decision-making based on general concepts and its particular biases.

The article, which lays out a broad research agenda for neuroscience, is featured this month in a special edition of Neuron, a journal published by Cell Press. The edition presents ideas that first appeared as part of a workshop at the University of Copenhagen last September titled “How Does the Brain Work?”

“Evolution has given us what we call a good model bias,” Pitkow said. “It’s been known for a couple of decades that very simple neural networks can compute any function, but those universal networks can be enormous, requiring extraordinary time and resources.

“In contrast, if you have the right kind of model — not a completely general model that could learn anything, but a more limited model that can learn specific things, especially the kind of things that often happen in the real world — then you have a model that’s biased. In this sense, bias can be a positive trait. We use it to be sensitive to the right things in the world that we inhabit. Of course, the flip side is that when our brain’s bias is not matched to reality, it can lead to severe problems.”

The researchers said simple tests of brain processes, like those in which subjects choose between two options, provide only simple results. “Before we had access to large amounts of data, neuroscience made huge strides from using simple tasks, and they’ll remain very useful,” Pitkow said. “But for computations that we think are most important about the brain, there are things you just can’t reveal with some of those tasks.” Pitkow and Angelaki wrote that tasks should incorporate more diversity — like nuisance variables and uncertainty — to better simulate real-world conditions that the brain evolved to handle.

They suggested that the brain infers solutions based on statistical crosstalk between redundant population codes. Population codes are responses by collections of neurons that are sensitive to certain inputs, like the shape or movement of an object. Pitkow and Angelaki think that to better understand the brain, it can be more useful to describe what these populations compute, rather than precisely how each individual neuron computes it. Pitkow said this means thinking “at the representational level” rather than the “mechanistic level,” as described by the influential vision scientist David Marr.

The research has implications for artificial intelligence, another interest of both researchers.

“A lot of artificial intelligence has done impressive work lately, but it still fails in some spectacular ways,” Pitkow said. “They can play the ancient game of Go and beat the best human player in the world, as done recently by DeepMind’s AlphaGo about a decade before anybody expected. But AlphaGo doesn’t know how to pick up the Go pieces. Even the best algorithms are extremely specialized. Their ability to generalize is often still pretty poor. Our brains have a much better model of the world; We can learn more from less data. Neuroscience theories suggest ways to translate experiments into smarter algorithms that could lead to a greater understanding of general intelligence.”

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Materials provided by Rice University. Note: Content may be edited for style and length.

Genes influence ability to read a person’s mind from their eyes

Our DNA influences our ability to read a person’s thoughts and emotions from looking at their eyes, suggests a new study published in the journal Molecular Psychiatry.

Twenty years ago, a team of scientists at the University of Cambridge developed a test of ‘cognitive empathy’ called the ‘Reading the Mind in the Eyes’ Test (or the Eyes Test, for short). This revealed that people can rapidly interpret what another person is thinking or feeling from looking at their eyes alone. It also showed that some of us are better at this than others, and that women on average score better on this test than men.

Now, the same team, working with the genetics company 23andMe along with scientists from France, Australia and the Netherlands, report results from a new study of performance on this test in 89,000 people across the world. The majority of these were 23andMe customers who consented to participate in research. The results confirmed that women on average do indeed score better on this test.

More importantly, the team confirmed that our genes influence performance on the Eyes Test, and went further to identify genetic variants on chromosome 3 in women that are associated with their ability to “read the mind in the eyes.”

The study was led by Varun Warrier, a Cambridge PhD student, and Professors Simon Baron-Cohen, Director of the Autism Research Centre at the University of Cambridge, and Thomas Bourgeron, of the University Paris Diderot and the Institut Pasteur.

Interestingly, performance on the Eyes Test in males was not associated with genes in this particular region of chromosome 3. The team also found the same pattern of results in an independent cohort of almost 1,500 people who were part of the Brisbane Longitudinal Twin Study, suggesting the genetic association in females is a reliable finding.

The closest genes in this tiny stretch of chromosome 3 include LRRN1 (Leucine Rich Neuronal 1) which is highly active in a part of the human brain called the striatum, and which has been shown using brain scanning to play a role in cognitive empathy. Consistent with this, genetic variants that contribute to higher scores on the Eyes Test also increase the volume of the striatum in humans, a finding that needs to be investigated further.

Previous studies have found that people with autism and anorexia tend to score lower on the Eyes Test. The team found that genetic variants that contribute to higher scores on the Eyes Test also increase the risk for anorexia, but not autism. They speculate that this may be because autism involves both social and non-social traits, and this test only measures a social trait.

Varun Warrier says: “This is the largest ever study of this test of cognitive empathy in the world. This is also the first study to attempt to correlate performance on this test with variation in the human genome. This is an important step forward for the field of social neuroscience and adds one more piece to the puzzle of what may cause variation in cognitive empathy.”

Professor Bourgeron adds: “This new study demonstrates that empathy is partly genetic, but we should not lose sight of other important social factors such as early upbringing and postnatal experience.”

Professor Baron-Cohen says: “We are excited by this new discovery, and are now testing if the results replicate, and exploring precisely what these genetic variants do in the brain, to give rise to individual differences in cognitive empathy. This new study takes us one step closer in understanding such variation in the population.”

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Materials provided by University of Cambridge. The original story is licensed under a Creative Commons License. Note: Content may be edited for style and length.

 

Scientists improve people’s creativity through electrical brain stimulation

Scientists have found a way to improve creativity through brain stimulation, according to researchers at Queen Mary University of London (QMUL) and Goldsmiths University of London.

They achieved this by temporarily suppressing a key part of the frontal brain called the left dorsolateral prefrontal cortex (DLPFC), which is involved in most of our thinking and reasoning.

The results, published in the journal Scientific Reports, show that participants who received the intervention showed an enhanced ability to ‘think outside the box’.

“We solve problems by applying rules we learn from experience, and the DLPFC plays a key role in automating this process,” commented Dr Caroline Di Bernardi Luft, first author from QMUL’s School of Biological and Chemical Sciences who conducted the research while previously working at Goldsmiths University of London, with Dr Michael Banissy and Professor Joydeep Bhattacharya.

“It works fine most of the time, but fails spectacularly when we encounter new problems which require a new style of thinking — our past experience can indeed block our creativity. To break this mental fixation, we need to loosen up our learned rules,” added Dr Luft.

The researchers used a technique called transcranial direct current stimulation (tDCS), which involved passing a weak constant electrical current through saline-soaked electrodes positioned over the scalp to modulate the excitability of the DLPFC. Depending on the direction of the current flow, DLPFC was temporarily suppressed or activated. The very low currents applied ensured that it would not cause any harm or unpleasant sensation.

Sixty participants were tested on their creative problem solving ability before and after receiving one of the following interventions: DLPFC being suppressed, DLPFC being activated, and DLPFC being unstimulated. The participants solved “matchstick problems,” some of which are hard, because to solve these problems, participants need to relax the learnt rules of arithmetic and algebra.

The participants whose DLPFC was temporarily suppressed by the electrical stimulation were more likely to solve hard problems than other participants whose DLPFC was activated or not stimulated. This demonstrates that suppressing DLPFC briefly can help breaking mental assumptions learned from experience and thinking outside the box.

But the researchers also observed that these participants got worse at solving problems with a higher working memory demand (where many items are needed to be held in mind at once). These problems require the participants to try a number of different moves until finding the solution, which means they have to keep track of their mental operations.

“These results are important because they show the potential of improving mental functions relevant for creativity by non-invasive brain stimulation methods,” commented Dr Luft.

“However, our results also suggest that potential applications of this technique will have to consider the target cognitive effects in more detail rather than just assuming tDCS can improve cognition as claimed by some companies which are starting to sell tDCS machines for home users,” she added.

“I would say that we are not yet in a position to wear an electrical hat and start stimulating our brain hoping for a blanket cognitive gain.”

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Materials provided by Queen Mary University of London. Note: Content may be edited for style and length.

Even moderate drinking linked to a decline in brain health, finds study

Alcohol consumption, even at moderate levels, is associated with increased risk of adverse brain outcomes and steeper decline in cognitive (mental) skills, finds a study published by The BMJ today.

These results support the recent reduction in alcohol guidance in the UK and raise questions about the current limits recommended in the US, say the authors.

Heavy drinking is known to be associated with poor brain health, but few studies have examined the effects of moderate drinking on the brain — and results are inconsistent.

So a team of researchers based at the University of Oxford and University College London set out to investigate whether moderate alcohol consumption has a beneficial or harmful association — or no association at all — with brain structure and function.

They used data on weekly alcohol intake and cognitive performance measured repeatedly over 30 years (1985-2015) for 550 healthy men and women who were taking part in the Whitehall II study.

This study is evaluating the impact of social and economic factors on the long term health of around 10,000 British adults.

Participants had an average age of 43 at the start of the study and none were alcohol dependent. Brain function tests were carried out at regular intervals and at the end of the study (2012-15), participants underwent an MRI brain scan.

Several factors that could have influenced the results (known as confounding) were taken into account, such as age, sex, education, social class, physical and social activity, smoking, stroke risk and medical history.

After adjusting for these confounders, the researchers found that higher alcohol consumption over the 30 year study period was associated with increased risk of hippocampal atrophy — a form of brain damage that affects memory and spatial navigation.

While those consuming over 30 units a week were at the highest risk compared with abstainers, even those drinking moderately (14-21 units per week) were three times more likely to have hippocampal atrophy compared with abstainers.

There was no protective effect of light drinking (up to 7 units per week) over abstinence.

Higher consumption was also associated with poorer white matter integrity (critical for efficient cognitive functioning) and faster decline in language fluency (how many words beginning with a specific letter can be generated in one minute).

But no association was found with semantic fluency (how many words in a specific category can be named in one minute) or word recall.

The authors point out that this is an observational study, so no firm conclusions can be drawn about cause and effect, and say some limitations could have introduced bias. However, key strengths include the information on long term alcohol consumption and the detailed available data on confounding factors.

As such, they say their findings have important potential public health implications for a large sector of the population.

“Our findings support the recent reduction in UK safe limits and call into question the current US guidelines, which suggest that up to 24.5 units a week is safe for men, as we found increased odds of hippocampal atrophy at just 14-21 units a week, and we found no support for a protective effect of light consumption on brain structure,” they write.

“Alcohol might represent a modifiable risk factor for cognitive impairment, and primary prevention interventions targeted to later life could be too late,” they conclude.

In a linked editorial, Killian Welch, consultant neuropsychiatrist at the Royal Edinburgh Hospital, says these findings “strengthen the argument that drinking habits many regard as normal have adverse consequences for health.”

This is important, he adds. “We all use rationalisations to justify persistence with behaviours not in our long term interest. With publication of this paper, justification of “moderate” drinking on the grounds of brain health becomes a little harder.”

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Materials provided by BMJ. Note: Content may be edited for style and length.

Treating depression with software

A treatment for depression using Emotional Faces Memory Task (EFMT), a technology originally developed by two Mount Sinai researchers, resulted in a significantly greater reduction of major depressive disorder (MDD) symptoms compared to a control group, according to initial clinical results presented at the Society of Biological Psychiatry Annual Scientific Convention on May 19, 2017, in San Diego. EFMT is a cognitive-emotional treatment that is delivered via an app on the Click Neurobehavioral Intervention (CNI) platform , a clinically-validated patient engagement platform developed by Click Therapeutics™.

This treatment was developed at the Icahn School of Medicine at Mount Sinai by Brian Iacoviello, PhD, an Assistant Professor of Psychiatry who is Director of Scientific Affairs for Click Therapeutics, and Dennis S. Charney, MD, Anne and Joel Ehrenkranz Dean and Professor of Psychiatry, Neuroscience, and Pharmacological Sciences. The underlying mechanism for MDD that the intervention targets involves an imbalance in the activity of specific brain regions: individuals with MDD show hyperactivity of neural systems involved in emotion processing, such as the amygdala, coupled with decreased activity of systems involved in cognitive control and emotion regulation, such as the prefrontal cortex. The amygdala processes incoming emotionally salient stimuli, whereas the prefrontal cortex, as the executive center of the brain, decides whether the incoming stimuli are noteworthy.

Patients using this therapeutic are asked to identify an emotion displayed in a series of faces, and for each face, they are asked to identify the number of faces earlier in the series in which they encountered the same emotion. This aims to balance brain activity in these regions to work in concert with each other. In the trial, the therapeutic reduced MDD symptoms by 42 percent in the experimental group after six weeks compared to 15.7 percent in the control group, which was given a similar task using simple shapes instead of emotions. “The aim is to target the thinking abnormality we see in patients with MDD — that of perseverating, ruminating, obsessing, dwelling on the negative — by activating these two nodes (emotion processing and cognitive control) simultaneously. Thus, higher cognitive control regions will stay active even while the brain is processing salient emotional stimuli, giving the individual the capacity to shift their mindfulness and attention so that they are not perseverating,” said Dr. Iacoviello. The initial results demonstrate that the efficacy of this digital therapeutic is comparable to drug therapy, with a highly favorable safety profile. Dr. Iacoviello added, “We will be advancing these encouraging results to the next level, by incorporating this therapeutic into a highly engaging mobile platform and launching it through the CNI platform. It’s exciting to have the opportunity to test the program within a large health care system such as Mount Sinai.”

Dr. Charney said, “Mount Sinai embraces creativity, innovation, and entrepreneurship. This technology illustrates our strengths in translating health care discoveries from the academic setting into industry, and ultimately to the patients that will benefit from them.”

Mount Sinai Innovation Partners (MSIP), the commercialization-arm of the Icahn School of Medicine at Mount Sinai, has been a key partner in this development. Erik Lium, PhD, Senior Vice President at MSIP, said, “We strongly believed in the potential of this technology based on early trials at Mount Sinai, and are pleased with our commercial partnership with Click Therapeutics. We look forward to the development of this technology into a digital therapeutic that will be used to treat a major disease.”

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Materials provided by The Mount Sinai Hospital / Mount Sinai School of Medicine. Note: Content may be edited for style and length.