1. Brain cells show teamwork in short-term memory

    March 23, 2017 by Ashley

    From the University of Western Ontario press release:

    Nerve cells in our brains work together in harmony to store and retrieve short-term memory, and are not solo artists as previously thought, Western-led brain research has determined.

    The research turns on its head decades of studies assuming that single neurons independently encode information in our working memories.

    “These findings suggest that even neurons we previously thought were ‘useless’ because they didn’t individually encode information have a purpose when working in concert with other neurons,” said researcher Julio Martinez-Trujillo, based at the Robarts Research Institute and the Brain and Mind Institute at Western University.

    “Knowing they work together helps us better understand the circuits in the brain that can either improve or hamper executive function. And that in turn may have implications for how we work though brain-health issues where short-term memory is a problem, including Alzheimer disease, schizophrenia, autism, depression and attention deficit disorder.”

    Working memory is the ability to learn, retain and retrieve bits of information we all need in the short term: items on a grocery list or driving directions, for example. Working memory deteriorates faster in people with dementia or other disorders of the brain and mind.

    In the past, researchers have believed this executive function was the job of single neurons acting independently from one another — the brain’s version of a crowd of people in a large room all singing different songs in different rhythms and different keys. An outsider trying to decipher any tune in all that white noise would have an extraordinarily difficult task.

    This research, however, suggests many in the neuron throng are singing from the same songbook, in essence creating chords to strengthen the collective voice of memory. With neural prosthetic technology — microchips that can “listen” to many neurons at the same time — researchers are able to find correlations between the activity of many nerve cells. “Using that same choir analogy, you can start perceiving some sounds that have a rhythm, a tune and chords that are related to each other: in sum, short-term memories,” said Martinez-Trujillo, who is also an associate professor at Western’s Schulich School of Medicine & Dentistry.

    And while the ramifications of this discovery are still being explored, “this gives us good material to work with as we move forward in brain research. It provides us with the necessary knowledge to find ways to manipulate brain circuits and improve short term memory in affected individuals,” Martinez-Trujillo said.

    “The microchip technology also allows us to extract signals from the brain in order to reverse-engineer brain circuitry and decode the information that is in the subject’s mind. In the near future, we could use this information to allow cognitive control of neural prosthetics in patients with ALS or severe cervical spinal cord injury,” said Adam Sachs, neurosurgeon and associate scientist at The Ottawa Hospital and assistant professor at the University of Ottawa Brain and Mind Research Institute.


  2. It’s a bird, it’s a plane, it’s – a key discovery about human memory

    March 22, 2017 by Ashley

    From the Johns Hopkins University press release:

    As Superman flies over the city, people on the ground famously suppose they see a bird, then a plane, and then finally realize it’s a superhero. But they haven’t just spotted the Man of Steel — they’ve experienced the ideal conditions to create a very strong memory of him.

    Johns Hopkins University cognitive psychologists are the first to link human’s long-term visual memory with how things move. The key, they found, lies in whether we can visually track an object. When people see Superman, they don’t think they’re seeing a bird, a plane and a superhero. They know it’s just one thing — even though the distance, lighting and angle change how he looks.

    People’s memory improves significantly with rich details about how an object’s appearance changes as it moves through space and time, the researchers concluded. The findings, which shed light on long-term memory and could advance machine learning technology, appear in this month’s Journal of Experimental Psychology: General.

    “The way I look is only a small part of how you know who I am,” said co-author Jonathan Flombaum, an assistant professor in the Department of Psychological and Brain Sciences. “If you see me move across a room, you’re getting data about how I look from different distances and in different lighting and from different angles. Will this help you recognize me later? No one has ever asked that question. We find that the answer is yes.”

    Humans have a remarkable memory for objects, says co-author Mark Schurgin, a graduate student in Flombaum’s Visual Thinking Lab. We recognize things we haven’t seen in decades — like eight-track tapes and subway tokens. We know the faces of neighbors we’ve never even met. And very small children will often point to a toy in a store after seeing it just once on TV.

    Though people almost never encounter a single object the exact same way twice, we recognize them anyway.

    Schurgin and Flombaum wondered if people’s vast ability for recall, a skill machines and computers cannot come close to matching, had something to do with our “core knowledge” of the world, the innate understanding of basic physics that all humans, and many animals, are born with. Specifically, everyone knows something can’t be in two places at once. So if we see one thing moving from place to place, our brain has a chance to see it in varying circumstances — and a chance to form a stronger memory of it.

    Likewise, if something is behaving erratically and we can’t be sure we’re seeing just one thing, those memories won’t form.

    “With visual memory, what matters to our brain is that an object is the same,” Flombaum said. “People are more likely to recognize an object if they see it at least twice, moving in the same path.”

    The researchers tested the theory in a series of experiments where people were shown very short video clips of moving objects, then given memory tests. Sometimes the objects appeared to move across the screen as a single object would. Other times they moved in ways we wouldn’t expect a single object to move, such as popping out from one side of the screen and then the other.

    In every experiment, subjects had significantly better memories — as much as nearly 20 percent better — of trackable objects that moved according to our expectations, the researchers found.

    “Your brain has certain automatic rules for how it expects things in the world to behave,” Schurgin said. “It turns out, these rules affect your memory for what you see.”

    The researchers expect the findings to help computer scientists build smarter machines that can recognize objects. Learning more about how humans do it, Flombaum said, will help us build systems that can do it.


  3. Skilled workers more prone to mistakes when interrupted

    March 20, 2017 by Ashley

    From the Michigan State University press release:

    Expertise is clearly beneficial in the workplace, yet highly trained workers in some occupations could actually be at risk for making errors when interrupted, indicates a new study by two Michigan State University psychology researchers.

    The reason: Experienced workers are generally faster at performing procedural tasks, meaning their actions are more closely spaced in time and thus more confusable when they attempt to recall where to resume a task after being interrupted.

    “Suppose a nurse is interrupted while preparing to give a dose of medication and then must remember whether he or she administered the dose,” said Erik Altmann, lead investigator on the project. “The more experienced nurse will remember less accurately than a less-practiced nurse, other things being equal, if the more experienced nurse performs the steps involved in administering medication more quickly.”

    That’s not to say skilled nurses should avoid giving medication, but only that high skill levels could be a risk factor for increased errors after interruptions and that experts who perform a task quickly and accurately have probably figured out strategies for keeping their place in a task, said Altmann, who collaborated with fellow professor Zach Hambrick.

    Their study, funded by the Office of Naval Research, is published online in the Journal of Experimental Psychology: General.

    For the experiment, 224 people performed two sessions of a computer-based procedural task on separate days. Participants were interrupted randomly by a simple typing task, after which they had to remember the last step they performed to select the correct step to perform next.

    In the second session, people became faster, and on most measures, more accurate, Altmann said. After interruptions, however, they became less accurate, making more errors by resuming the task at the wrong spot.

    “The faster things happen, the worse we remember them,” Altmann said, adding that when workers are interrupted in the middle of critical procedures, as in emergency rooms or intensive care units, they may benefit from training and equipment design that helps them remember where they left off.


  4. Might smartphones help to maintain memory in patients with mild Alzheimer’s disease?

    by Ashley

    From the IOS Press press release:

    The patient is a retired teacher who had reported memory difficulties 12 months prior to the study. These difficulties referred to trouble remembering names and groceries she wanted to purchase, as well as frequently losing her papers and keys. According to the patient and her husband, the main difficulties that she encountered were related to prospective memory (e.g., forgetting medical appointments or to take her medication).

    To help her with her symptoms, Mohamad El Haj, a psychologist and assistant professor at the University of Lille, proposed Google Calendar, a time-management and scheduling calendar service developed by Google. The patient accepted as she was already comfortable using her smartphone. She also declared that she preferred the application as it offers more discrete assistance than a paper-based calendar.

    With the patient and her husband, Dr. El Haj and his colleagues defined several prospective omissions in the patient, such as forgetting her weekly medical appointment, forgetting her weekly bridge game in the community club, and forgetting to go to weekly mass at the church. These omissions were targeted by sending automatic alerts, prompted by Google Calendar, at different times before each event (e.g., the medical appointment).

    The researchers compared omissions before after the use of Google Calendar, they observed less omission after implementing the application.

    The study is the first to suggest positive effects of smartphones applications on everyday life prospective memory in Alzheimer’s disease. The findings, published in Journal of Alzheimer’s disease, are encouraging, however, Dr. El Haj notes that this is a case study and therefore entails a few limitations, including generalizability of the results. The current, anecdotal findings require a larger study, not only to confirm or refute the findings reported here, but also to address challenges such as the long-term benefits of Google calendar.

    Regardless of its potential limitations, Dr. El Haj notes that this study addresses memory loss, the main cognitive hallmark of Alzheimer’s disease and the major concern of the patients and their families. By demonstrating positive effect of Google Calendar on prospective memory in this patient, Dr. El Haj hopes that his study paves the way for exploring the potential of smartphone-integrated memory aids in Alzheimer’s disease. The future generation of patients may be particularly sensitive to the use of smartphones as a tool to alleviate their memory compromise.


  5. People can match names to faces of strangers with surprising accuracy

    March 17, 2017 by Ashley

    From the American Psychological Association press release:

    IF

    If your name is Fred, do you look like a Fred? You might — and others might think so, too. New research published by the American Psychological Association has found that people appear to be better than chance at correctly matching people’s names to their faces, and it may have something to do with cultural stereotypes we attach to names.

    In the study, published in the Journal of Personality and Social Psychology, lead author Yonat Zwebner, a PhD candidate at The Hebrew University of Jerusalem at the time of the research, and colleagues conducted a series of experiments involving hundreds of participants in Israel and France. In each experiment, participants were shown a photograph and asked to select the given name that corresponded to the face from a list of four or five names. In every experiment, the participants were significantly better (25 to 40 percent accurate) at matching the name to the face than random chance (20 or 25 percent accurate depending on the experiment) even when ethnicity, age and other socioeconomic variables were controlled for.

    The researchers theorize the effect may be, in part, due to cultural stereotypes associated with names as they found the effect to be culture-specific. In one experiment conducted with students in both France and Israel, participants were given a mix of French and Israeli faces and names. The French students were better than random chance at matching only French names and faces and Israeli students were better at matching only Hebrew names and Israeli faces.

    In another experiment, the researchers trained a computer, using a learning algorithm, to match names to faces. In this experiment, which included over 94,000 facial images, the computer was also significantly more likely (54 to 64 percent accuracy) to be successful than random chance (50 percent accuracy).

    This manifestation of the name in a face might be due to people subconsciously altering their appearance to conform to cultural norms and cues associated with their names, according to Zwebner.

    “We are familiar with such a process from other stereotypes, like ethnicity and gender where sometimes the stereotypical expectations of others affect who we become,” said Zwebner. “Prior research has shown there are cultural stereotypes attached to names, including how someone should look. For instance, people are more likely to imagine a person named Bob to have a rounder face than a person named Tim. We believe these stereotypes can, over time, affect people’s facial appearance.”

    This was supported by findings of one experiment showing that areas of the face that can be controlled by the individual, such as hairstyle, were sufficient to produce the effect.

    “Together, these findings suggest that facial appearance represents social expectations of how a person with a particular name should look. In this way, a social tag may influence one’s facial appearance,” said co-author Ruth Mayo, PhD, also from The Hebrew University of Jerusalem. “We are subject to social structuring from the minute we are born, not only by gender, ethnicity and socioeconomic status, but by the simple choice others make in giving us our name.”


  6. Study notes how musical cues trigger different autobiographical memories

    March 16, 2017 by Ashley

    From the Springer press release:

    Happy memories spring to mind much faster than sad, scary or peaceful ones. Moreover, if you listen to happy or peaceful music, you recall positive memories, whereas if you listen to emotionally scary or sad music, you recall largely negative memories from your past. Those are two of the findings from an experiment in which study participants accessed autobiographical memories after listening to unknown pieces of music varying in intensity or emotional content. It was conducted by Signy Sheldon and Julia Donahue of McGill University in Canada, and is reported in the journal Memory & Cognition, published by Springer.

    The experiment tested how musical retrieval cues that differ on two dimensions of emotion — valence (positive and negative) and arousal (high and low) — influence the way that people recall autobiographical memories. A total of 48 participants had 30 seconds to listen to 32 newly composed piano pieces not known to them. The pieces were grouped into four retrieval cues of music: happy (positive, high arousal), peaceful (positive, low arousal), scary (negative, high arousal) and sad (negative, low arousal).

    Participants had to recall events in which they were personally involved, that were specific in place and time, and that lasted less than a day. As soon as a memory came to mind, participants pressed a computer key and typed in their accessed memory. The researchers noted how long it took participants to access a memory, how vivid it was, and the emotions associated with it. The type of event coming to mind was also considered, and whether for instance it was quite unique or connected with an energetic or social setting.

    Memories were found to be accessed most quickly based on musical cues that were highly arousing and positive in emotion, and could therefore be classified as happy. A relationship between the type of musical cue and whether it triggered the remembrance of a positive or a negative memory was also noted. The nature of the event recalled was influenced by whether the cue was positive or negative and whether it was high or low in arousal.

    “High cue arousal led to lower memory vividness and uniqueness ratings, but both high arousal and positive cues were associated with memories rated as more social and energetic,” explains Sheldon.

    During the experiment, the piano pieces were played to one half of the participants in no particular order, while for the rest the music was grouped together based on whether these were peaceful, happy, sad or scary pieces. This led to the finding that the way in which cues are presented influences how quickly and specifically memories are accessed. Cue valence also affects the vividness of a memory.

    More specifically, the researchers found that a greater proportion of clear memories were recalled when highly arousing positive cues were played in a blocked fashion. Positive cues also elicited more vivid memories than negative cues. In the randomized condition, negative cues were associated more vividly than positive cues.

    “It is possible that when cues were presented in a random fashion, the emotional content of the cue directed retrieval to a similar memory via shared emotional information,” notes Donahue.


  7. Poor sleep in early childhood may lead to cognitive, behavioral problems in later years

    March 15, 2017 by Ashley

    From the Massachusetts General Hospital press release:

    A study led by a Massachusetts General Hospital pediatrician finds that children ages 3 to 7 who don’t get enough sleep are more likely to have problems with attention, emotional control and peer relationships in mid-childhood. Reported online in the journal Academic Pediatrics, the study found significant differences in the responses of parents and teachers to surveys regarding executive function — which includes attention, working memory, reasoning and problem solving — and behavioral problems in 7-year-old children depending on how much sleep they regularly received at younger ages.

    “We found that children who get an insufficient amount of sleep in their preschool and early school-age years have a higher risk of poor neurobehavioral function at around age 7,” says Elsie Taveras, MD, MPH, chief of General Pediatrics at MassGeneral Hospital for Children , who led the study. “The associations between insufficient sleep and poorer functioning persisted even after adjusting for several factors that could influence the relationship.”

    As in previous studies from this group examining the role of sleep in several areas of child health, the current study analyzed data from Project Viva, a long-term investigation of the health impacts of several factors during pregnancy and after birth. Information used in this study was gathered from mothers at in-person interviews when their children were around 6 months, 3 years and 7 years old, and from questionnaires completed when the children were ages 1, 2, 4, 5 and 6. In addition, mothers and teachers were sent survey instruments evaluating each child’s executive function and behavioral issues — including emotional symptoms and problems with conduct or peer relationships, when children were around 7.

    Among 1,046 children enrolled in Project Viva, the study team determined which children were not receiving the recommended amount of sleep at specific age categories — 12 hours or longer at ages 6 months to 2 years, 11 hours or longer at ages 3 to 4 years, and 10 hours or longer at 5 to 7 years. Children living in homes with lower household incomes and whose mothers had lower education levels were more likely to sleep less than nine hours at ages 5 to 7. Other factors associated with insufficient sleep include more television viewing, a higher body mass index, and being African American.

    The reports from both mothers and teachers regarding the neurobehavioral function of enrolled children found similar associations between poor functioning and not receiving sufficient sleep, with teachers reporting even greater problems. Although no association was observed between insufficient sleep during infancy — ages 6 months to 2 years — and reduced neurobehavioral functioning in mid-childhood, Taveras notes that sleep levels during infancy often predict levels at later ages, supporting the importance of promoting a good quantity and quality of sleep from the youngest ages.

    “Our previous studies have examined the role of insufficient sleep on chronic health problems — including obesity — in both mothers and children,” explains Taveras, who is a professor of Pediatrics at Harvard Medical School (HMS). “The results of this new study indicate that one way in which poor sleep may lead to these chronic disease outcomes is by its effects on inhibition, impulsivity and other behaviors that may lead to excess consumption of high-calorie foods. It will be important to study the longer-term effects of poor sleep on health and development as children enter adolescence, which is already underway through Project Viva.”


  8. Media multitasking linked to distractibility among youth

    by Ashley

    From the University of Helsinki press release:

    The aim of Mona Moisala’s doctoral dissertation was to study patterns of activity in cortical networks related to attention and working memory, as well as to investigate associations between performance in working memory and attention tasks and the extent of daily technology-mediated activities in 13-24-year-old subjects from Finland.

    The results reveal that the youth that reported a greater tendency to use several media simultaneously during their free time, struggled with the attention-related tasks in a laboratory setting.

    “They had a harder time filtering out distractive stimuli. This was also seen as higher activity in regions of the frontal lobe, which can be a sign of excessive strain,” Moisala points out.

    However, it is unclear whether the distractibility is caused by media-multitasking or vice versa.

    Moisala used functional magnetic resonance imaging (fMRI) to record brain activity during task performance. Using this method, she also investigated why multitasking is difficult.

    “The results demonstrated that during division of attention between listening and reading, competition for neural resources in regions shared by these tasks was a major factor limiting the performance,” Moisala says.

    The studied youth who reported more daily computer gaming activity showed enhanced working memory functioning and better reaction times in the laboratory tasks. It was also easier for them to switch between visual and auditory attention.

    The cognitive benefits of computer gaming have also been reported in previous studies.

    “Taken together, the results from these studies are of great importance, since it is vital to understand how the increasing amount of on-screen time might affect or interact with the cognitive and brain functioning of the current youth,” Moisala says.

    She repeated the laboratory tasks two years later to gather data for the follow-up research for which she now seeks funding.

    “This data is exceptionally extensive and provides us with the possibility to investigate the effects of technology use on the developing brain,” Moisala says.


  9. Antibiotics that kill gut bacteria also stop growth of new brain cells

    May 23, 2016 by Ashley

    From the Cell Press media release:

    magnesium pillsAntibiotics strong enough to kill off gut bacteria can also stop the growth of new brain cells in the hippocampus, a section of the brain associated with memory, reports a study in mice published May 19 in Cell Reports. Researchers also uncovered a clue to why– a type of white blood cell seems to act as a communicator between the brain, the immune system, and the gut.

    “We found prolonged antibiotic treatment might impact brain function,” says senior author Susanne Asu Wolf of the Max-Delbrueck-Center for Molecular Medicine in Berlin, Germany. “But probiotics and exercise can balance brain plasticity and should be considered as a real treatment option.”

    Wolf first saw clues that the immune system could influence the health and growth of brain cells through research into T cells nearly 10 years ago. But there were few studies that found a link from the brain to the immune system and back to the gut.

    In the new study, the researchers gave a group of mice enough antibiotics for them to become nearly free of intestinal microbes. Compared to untreated mice, the mice who lost their healthy gut bacteria performed worse in memory tests and showed a loss of neurogenesis (new brain cells) in a section of their hippocampus that typically produces new brain cells throughout an individual’s lifetime. At the same time that the mice experienced memory and neurogenesis loss, the research team detected a lower level of white blood cells (specifically monocytes) marked with Ly6Chi in the brain, blood, and bone marrow. So researchers tested whether it was indeed the Ly6Chi monocytes behind the changes in neurogenesis and memory.

    In another experiment, the research team compared untreated mice to mice that had healthy gut bacteria levels but low levels of Ly6Chi either due to genetics or due to treatment with antibodies that target Ly6Chi cells. In both cases, mice with low Ly6Chi levels showed the same memory and neurogenesis deficits as mice in the other experiment who had lost gut bacteria. Furthermore, if the researchers replaced the Ly6Chi levels in mice treated with antibiotics, then memory and neurogenesis improved.

    For us it was impressive to find these Ly6Chi cells that travel from the periphery to the brain, and if there’s something wrong in the microbiome, Ly6Chi acts as a communicating cell,” says Wolf.

    Luckily, the adverse side effects of the antibiotics could be reversed. Mice who received probiotics or who exercised on a wheel after receiving antibiotics regained memory and neurogenesis. “The magnitude of the action of probiotics on Ly6Chi cells, neurogenesis, and cognition impressed me,” she says.

    But one result in the experiment raised more questions about the gut’s bacteria and the link between Ly6Chi and the brain. While probiotics helped the mice regain memory, fecal transplants to restore a healthy gut bacteria did not have an effect.

    “It was surprising that the normal fecal transplant recovered the broad gut bacteria, but did not recover neurogenesis,” says Wolf. “This might be a hint towards direct effects of antibiotics on neurogenesis without using the detour through the gut. To decipher this we might treat germ free mice without gut flora with antibiotics and see what is different.”

    In the future, researchers also hope to see more clinical trials investigating whether probiotic treatments will improve symptoms in patients with neurodegenerative and psychiatric disorders.”We could measure the outcome in mood, psychiatric symptoms, microbiome composition and immune cell function before and after probiotic treatment,” says Wolf.


  10. Study shows how the brain switches into memory mode

    May 11, 2016 by Ashley

    From the University of Bonn media release:

    brain scanResearchers from Germany and the USA have identified an important mechanism with which memory switches from recall to memorization mode.

    The study may shed new light on the cellular causes of dementia. The work was directed by the University of Bonn and the German Center for Neurodegenerative Diseases (DZNE). It is being published in the journal Neuron.

    Because of its shape, the control center of memory bears the poetic name of “hippocampus” (seahorse). New sensations to be stored continually enter this region of the brain. But at the same time, the hippocampus is also the guardian of memories: It retrieves stored information from the depths of memory.

    The hippocampus is also an important transport junction. And just like rush hour in a major city, it also needs a regulating hand to control the opposing flows of information. The researchers from Bonn, Los Angeles and Palo Alto have now identified such a memory traffic policeman. Certain cells in the brain, the hippocampal astrocytes, ensure that the new information is given priority. The mind thus switches into memorization mode; by contrast, the already saved memories must wait.

    However, the astrocytes themselves only take orders: They react to the neurotransmitter acetylcholine, which is released in particular in novel situations. It has been known for several years that acetylcholine promotes the storage of new information. How this happens has only been partly understood. “In our work, we were able to show for the first time that acetylcholine stimulates astrocytes which then are induced to release the transmitter glutamate,” explains Milan Pabst, who is a doctoral candidate at the Laboratory for Experimental Epileptology of the University of Bonn. “The released glutamate then activates inhibitory nerve cells which inhibit a pathways mediating the retrieval of memories.”

    The researchers working with the neuroscientist Prof. Dr. Heinz Beck genetically modified nerve cells so that they could be activated by light and then release acetylcholine. Using this trick, they were able to clarify the mechanism using recordings in living brain tissue sections. “However, we also show that, in the brains of living mice, acetylcholine has the same effect on the activity of the neurons,” explains Pabst’s colleague, Dr. Holger Dannenberg.

    Astrocytes have long since been underestimated

    Another reason this result is interesting is because astrocytes themselves are not nerve cells. They belong to what are known as glial cells. Until the turn of the millennium, they were still considered to merely serve as mechanical support to the real stars of the brain, the neurons.

    In recent decades, however, it has become increasingly clearer that this image is far from correct. It is known by now that astrocytes can release neurotransmitters — the messengers by which neurons communicate with each other — or even remove them from the brain. “It was previously unknown that the astrocytes are involved in central memory processes through the mechanism which has now been discovered,” explains Prof. Beck. However, an observation made by US scientists in 2014 fits into this context: If astrocytes’ function is inhibited, this has a negative effect on the recognition of objects.

    The results may also shed new light on the cellular causes of memory disorders. Thus there are indications that the controlled secretion of acetylcholine is disrupted in patients with Alzheimer’s dementia. “However, we have not investigated whether the mechanism we discovered is also impacted,” stresses Pabst.