Neuroscientists explore the intersection of music and memory

The soundtrack of this story begins with a vaguely recognizable and pleasant groove. But if I stop writing and just listen for a second, the music reveals itself completely. In Freddie Hubbard's comfortable, lilting trumpet solo over Herbie Hancock's melodic, repetitive piano vamping, I recognize "Cantaloupe Island." Then, with my fingers again poised at the keyboard, Freddie and Herbie fade into the background, followed by other instrumental music: captivating -- but not distracting -- sonic nutrition, feeding my concentration and productivity.

Somewhere, I think, Yiren Ren is studying, focused on her research that demonstrates how music impacts learning and memory. Possibly, she's listening to Norah Jones, or another musician she's comfortable with. Because that's how it works: The music we know and might love, music that feels predictable or even safe -- that music can help us study and learn. Meanwhile, Ren has also discovered, other kinds of music can influence our emotions and reshape old memories.

Ren, a sixth-year Ph.D. student in Georgia Tech's School of Psychology, explores these concepts as the lead author of two new research papers in the journals PLOS Oneand Cognitive, Affective, & Behavioral Neuroscience (CABN).

"These studies are connected because they both explore innovative applications of music in memory modulation, offering insights for both every day and clinical use," says Ren.

But the collective research explores music's impacts in very different ways, explains Ren's faculty advisor and co-author of the study, Thackery Brown.

"One paper looks at how music changes the quality of your memory when you're first forming it -- it's about learning," says Brown, a cognitive neuroscientist who runs the MAP (Memory, Affect, and Planning) Lab at Tech. "But the other study focuses on memories we already have and asks if we can change the emotions attached to them using music."

Making Moods With Music

When we watch a movie with a robust score -- music created to induce emotions -- what we're hearing guides us exactly where the composer wants us to go. In their CABN study, Ren, Brown, and their collaborators from the University of Colorado (including former Georgia Tech Assistant Professor Grace Leslie) report that this kind of "mood music" can also be powerful enough to change how we remember our past.

Their study included 44 Georgia Tech students who listened to film soundtracks while recalling a difficult memory. Ren is quick to point out that this was not a clinical trial, so these participants were not identified as people suffering from mood disorders: "We wanted to start off with a random group of people and see if music has the power to modulate the emotional level of their memories."

Turns out, it does. The participants listened to movie soundtracks and incorporated new emotions into their memories that matched the mood of the music. And the effect was lasting. A day later, when the participants recalled these same memories -- but without musical accompaniment -- their emotional tone still matched the tone of the music played the day before.

The researchers could watch all this happening with fMRI (functional magnetic resonance imaging). They could see the altered brain activity in the study participants, the increased connectivity between the amygdala, where emotions are processed, and other areas of the brain associated with memory and integrating information.

"This sheds light on the malleability of memory in response to music, and the powerful role music can play in altering our existing memories," says Ren.

Ren is herself a multi-instrumentalist who originally planned on being a professional musician. As an undergraduate at Boston University, she pursued a dual major in film production and sound design, and psychology.

She found a way to combine her interests in music and neuroscience and is interested in how music therapy can be designed to help people with mood disorders like post-traumatic stress disorder (PTSD) or depression, "particularly in cases where someone might overexaggerate the negative components of a memory," Ren says.

There is no time machine that will allow us to go back and insert happy music into the mix while a bad event is happening and a memory is being formed, "but we can retrieve old memories while listening to affective music," says Brown. "And perhaps we can help people shift their feelings and reshape the emotional tone attached to certain memories."

Embracing the Familiar

The second study asks a couple of old questions: Should we listen to music while we work or study? And if so, are there more beneficial types of music than others? The answer to both questions might lie, at least partially, within the expansive parameters of personal taste. But even so, there are limits.

Think back to my description of "Cantaloupe Island" at the beginning of this story and how a familiar old jazz standard helped keep this writer's brain and fingers moving. In the same way, Norah Jones helps Ren when she's working on new research around music and memory. But if, for some reason, I wanted to test my concentration, I'd play a different kind of jazz, maybe 1950s bebop with its frenetic pace and off-center tone, or possibly a chorus of screeching cats. Same effect. It would demand my attention, and no work would get done.

For this study, Ren combined her gifts as a musician and composer with her research interests in examining whether music can improve -- or impair -- our ability to learn or remember new information. "We wanted to probe music's potential as a mnemonic device that helps us remember information more easily," she says. (An example of a mnemonic device is "Every Good Boy Does Fine," which stands for E-G-B-D-F and helps new piano players learn the order of notes on a keyboard.)

This study's 48 participants were asked to learn sequences of abstract shapes while listening to different types of music. Ren played a piece of music, in a traditional or familiar pattern of tone, rhythm, and melody. She then played the exact same set of notes, but out of order, giving the piece an atonal structure.

When they listened to familiar, predictable music, participants learned and remembered the sequences of shapes quicker as their brains created a structured framework, or scaffold, for the new information. Meanwhile, music that was familiar but irregular (think of this writer and the bebop example) made it harder for participants to learn.

"Depending its familiarity and structure, music can help or hinder our memory," says Ren, who wants to deepen her focus on the neural mechanisms through which music influences human behavior.

She plans to finish her Ph.D. studies this December and is seeking postdoctoral research positions that will allow her to continue the work she's started at Georgia Tech. Building on that, Ren wants to develop music-based therapies for conditions like depression or PTSD, while also exploring new rehabilitation strategies for aging populations and individuals with dementia.

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Study: Best way to memorize stuff? It depends...

Recent experiments by psychologists at Temple University and the University of Pittsburgh shed new light on how we learn and how we remember our real-world experiences.

The research, described in the March 12 online edition of Proceedings of the National Academy of Sciences (PNAS), suggests that varying what we study and spacing out our learning over time can both be helpful for memory -- it just depends on what we're trying to remember.

"Lots of prior research has shown that learning and memory benefit from spacing study sessions out," said Benjamin Rottman, an associate professor of psychology and director of the Causal Learning and Decision-Making Lab at Pitt.

"For example, if you cram the night before a test, you might remember the information the next day for the test, but you will probably forget it fairly soon," he added. "In contrast, if you study the material on different days leading up to the test, you will be more likely to recall it for a longer period of time."

But while the "spacing effect" is one of the most replicated findings in psychological research, much of this work has been predicated on the idea that what you are trying to learn -- the content of the experience itself -- repeats identically each time. Yet that is rarely the case in real life, when some features of our experiences may stay the same, but others are likely to change. For example, imagine repeat trips to your local coffeeshop. While many features may stay the same on each visit, a new barista may be serving you. How does the spacing effect work in light of such variation across experiences?

In two experiments, Temple and Pitt researchers asked participants to repeatedly study pairs of items and scenes that were either identical on each repetition or in which the item stayed the same but the scene changed each time.

One of the experiments asked participants to learn and to test their memory via their smartphones -- an unusual approach for learning and memory research. This enabled researchers to ask participants to learn pairs at various times of the day across 24 hours, more accurately representing how people actually learn information.

In the second experiment, researchers collected data online in a single session.

Emily Cowan, lead author on the PNAS paper and a postdoctoral fellow in Temple's Adaptive Memory Lab, explained: "The combination of these two large-scale experiments allowed us to look at the timing of these 'spacing effects' across both long timescales -- for example, hours to days -- in Experiment No. 1 versus short timescales -- for example, seconds to minutes -- in Experiment No. 2. With this, we were able to ask how memory is impacted both by what is being learned -- whether that is an exact repetition or instead, contains variations or changes -- as well as when it is learned over repeated study opportunities.

"In other words, using these two designs, we could examine how having material that more closely resembles our experiences of repetition in the real world -- where some aspects stay the same but others differ -- impacts memory if you are exposed to that information in quick succession versus over longer intervals… from seconds to minutes, or hours to days."

As in prior experiments, researchers found that spaced learning benefited item memory. But they also found that memory was better for the items that had been paired with different scenes compared with those shown with the same scene each time. For example, if you want to remember a new person's name, repeating the name but associating it with different information about the person can actually be helpful.

"In contrast," Rottman said, "we found that for associative memory -- memory for the item and which scene it was paired with -- benefited from stability. Spacing only benefited memory for the pairs that were repeated exactly, and only if there were pretty long gaps -- hours to days -- between study opportunities. For example, if you are trying to remember the new person's name and something about them, like their favorite food, it is more helpful to repeat that same exact name-food pairing multiple times with spacing between each."

The Pitt-Temple experiments represent basic memory research. "Because of how nuanced memory is, it is hard to provide clear advice for things like studying for a test because the sort of material can be so different," Rottman said. "But in theory our findings should be broadly relevant to different sorts of tasks, like remembering someone's name and things about them, studying for a test, and learning new vocabulary in a foreign language.

"At the same time, because all these sorts of tasks have lots of differences, it is hard to make really concrete advice for them. We would need to do follow-up research to provide more concrete guidance for each case."

Cowan continued: "This work demonstrates the benefits of spaced learning on memory are not absolute, instead depending on the variability present in the content across repetitions and the timing between learning opportunities, expanding our current understanding of how the way in which we learn information can impact how it is remembered. Our work suggests that both variability and spacing may present methods to improve our memory for isolated features and associative information, respectively, raising important applications for future research, education, and our everyday lives."

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The brain is 'programmed' for learning from people we like

Our brains are "programmed" to learn more from people we like -- and less from those we dislike. This has been shown by researchers in cognitive neuroscience in a series of experiments.

Memory serves a vital function, enabling us to learn from new experiences and update existing knowledge.

We learn both from individual experiences and from connecting them to draw new conclusions about the world.

This way, we can make inferences about things that we don't necessarily have direct experience of. This is called memory integration and makes learning quick and flexible.

Inês Bramão, associate professor of psychology at Lund University, provides an example of memory integration: Say you're walking in a park.

You see a man with a dog. A few hours later, you see the dog in the city with a woman.

Your brain quickly makes the connection that the man and woman are a couple even though you have never seen them together.

"Making such inferences is adaptive and helpful. But of course, there's a risk that our brain draws incorrect conclusions or remembers selectively," says Inês Bramão.

Important who provides the information

To examine what affects our ability to learn and make inferences, Inês Bramão, along with colleagues Marius Boeltzig and Mikael Johansson, set up experiments where participants were tasked with remembering and connecting different objects.

It could be a bowl, ball, spoon, scissors, or other everyday objects.

It turned out that memory integration, i.e., the ability to remember and connect information across learning events, was influenced by who presented it. If it was a person the participant liked, connecting the information was easier compared to when the information came from someone the participant disliked.

The participants provided individual definitions of 'like' and 'dislike' based on aspects such as political views, major, eating habits, favorite sports, hobbies, and music.

Can be translated to politics

The findings can be applied in real life, according to the researchers.

Inês Bramão takes a hypothetical example from politics:

"A political party argues for raising taxes to benefit healthcare. Later, you visit a healthcare center and notice improvements have been made. If you sympathize with the party that wanted to improve healthcare through higher taxes, you're likely to attribute the improvements to the tax increase, even though the improvements might have had a completely different cause."

About fundamental mechanisms

There's already vast research describing that people learn information differently depending on the source and how that characterizes polarization and knowledge resistance.

"What our research shows is how these significant phenomena can partly be traced back to fundamental principles that govern how our memory works," says Mikael Johansson, professor of psychology at Lund University.

We are more inclined to form new connections and update knowledge from information presented by groups we favor.

Innate way of handling information

Understanding the roots of polarization, resistance to new knowledge, and related phenomena from basic brain functions offers a deeper insight into these complex behaviors, the researchers argue.

So, it's not just about filter bubbles on social media but also about an innate way of assimilating information.

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Serotonin loss may contribute to cognitive decline in the early stages of Alzheimer's disease

Comparing PET scans of more than 90 adults with and without mild cognitive impairment (MCI), Johns Hopkins Medicine researchers say relatively lower levels of the so-called "happiness" chemical, serotonin, in parts of the brain of those with MCI may play a role in memory problems including Alzheimer's disease.

The findings, first published online Sept. 13 in the Journal of Alzheimer's Disease, lend support to growing evidence that measurable changes in the brain happen in people with mild memory problems long before an Alzheimer's diagnosis, and may offer novel targets for treatments to slow or stop disease progression.

"The study shows that people with mild cognitive impairment already display loss of the serotonin transporter. This measure that reflects serotonin degeneration is associated with problems with memory, even when we take into account in our statistical model MRI measures of neurodegeneration and PET measures of the amyloid protein that are associated with Alzheimer's Disease," says Gwenn Smith, Ph.D., professor of psychiatry and behavioral sciences at the Johns Hopkins University School of Medicine.

MCI describes the diagnostic stage between normal brain function in aging and Alzheimer's Disease (AD). Symptoms of MCI include frequent forgetfulness of recent events, word finding difficulty, and loss of the sense of smell.

Those with MCI may stay in this stage indefinitely, or progress to more severe forms of cognitive deficits, giving urgency to the search for predictive markers, and possible early prevention interventions, investigators say.

The investigators cautioned that their study showed a correlation between lower serotonin transporter levels and memory problems in MCI, and was not designed to show causation or the role of serotonin in the progression from MCI to AD. To answer these questions, further research is needed to study over time healthy controls and individuals with MCI to demonstrate the role of serotonin in disease progression.

For the study, the Hopkins scientists recruited 49 volunteers with MCI, and 45 healthy adults ages 55 and older who underwent an MRI to measure changes in brain structure and two positron emission tomography (PET) scans of their brains at Johns Hopkins between 2009 and 2022.

The research team used PET scans to look specifically at the serotonin transporter -- a neurotransmitter, or brain chemical long associated with positive mood, appetite and sleep -- and to look at the amyloid-beta protein (Aβ) distribution in the brain.

Aβ is thought to play a central role in the pathology of AD. Studies in mice done at Johns Hopkins have shown that serotonin degeneration occurs before the development of widespread beta-amyloid deposits in the brain.

Loss of serotonin is often associated with depression, anxiety, and psychological disorders.

Researchers found that MCI patients had lower levels of the serotonin transporter, and higher levels of Aβ than healthy controls.

The MCI patients had up to 25% lower serotonin transporter levels in cortical and limbic regions than healthy controls.

In particular, they report, lower serotonin transporter levels were found in cortical, limbic, and subcortical regions of the brains in those with MCI, areas specifically responsible for executive function, emotion, and memory.

"The correlation we observed between lower serotonin transporters and memory problems in MCI is important because we may have identified a brain chemical that we can safely target that may improve cognitive deficits and, potentially, depressive symptoms," says Smith.

"If we can show that serotonin loss over time is directly involved in the transition from MCI to AD, recently developed antidepressant medications may be an effective way to improve memory deficits and depressive symptoms and thus, may be a powerful way forward to slow disease progression."

Researchers say future studies include longitudinal follow up of individuals with MCI to compare serotonin degeneration to the increase in and Aβ levels, as well as the increase in levels of the Tau protein that is also associated with AD compared to healthy adults.

They are also studying multi-modal antidepressant drugs to treat depression and memory deficits in hopes of mitigating and halting symptoms.

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Jellyfish, with no central brain, shown to learn from past experience

Even without a central brain, jellyfish can learn from past experiences like humans, mice, and flies, scientists report for the first time on September 22 in the journal Current Biology. They trained Caribbean box jellyfish (Tripedalia cystophora) to learn to spot and dodge obstacles. The study challenges previous notions that advanced learning requires a centralized brain and sheds light on the evolutionary roots of learning and memory.

No bigger than a fingernail, these seemingly simple jellies have a complex visual system with 24 eyes embedded in their bell-like body. Living in mangrove swamps, the animal uses its vision to steer through murky waters and swerve around underwater tree roots to snare prey. Scientists demonstrated that the jellies could acquire the ability to avoid obstacles through associative learning, a process through which organisms form mental connections between sensory stimulations and behaviors.

"Learning is the pinnacle performance for nervous systems," says first author Jan Bielecki of Kiel University, Germany. To successfully teach jellyfish a new trick, he says "it's best to leverage its natural behaviors, something that makes sense to the animal, so it reaches its full potential."

The team dressed a round tank with gray and white stripes to simulate the jellyfish's natural habitat, with gray stripes mimicking mangrove roots that would appear distant. They observed the jellyfish in the tank for 7.5 minutes. Initially, the jelly swam close to these seemingly far stripes and bumped into them frequently. But by the end of the experiment, the jelly increased its average distance to the wall by about 50%, quadrupled the number of successful pivots to avoid collision and cut its contact with the wall by half. The findings suggest that jellyfish can learn from experience through visual and mechanical stimuli.

"If you want to understand complex structures, it's always good to start as simple as you can," says senior author Anders Garm of the University of Copenhagen, Denmark. "Looking at these relatively simple nervous systems in jellyfish, we have a much higher chance of understanding all the details and how it comes together to perform behaviors."

The researchers then sought to identify the underlying process of jellyfish's associative learning by isolating the animal's visual sensory centers called rhopalia. Each of these structures houses six eyes and generates pacemaker signals that govern the jellyfish's pulsing motion, which spikes in frequency when the animal swerves from obstacles.

The team showed the stationary rhopalium moving gray bars to mimic the animal's approach to objects. The structure did not respond to light gray bars, interpreting them as distant. However, after the researchers trained the rhopalium with weak electric stimulation when the bars approach, it started generating obstacle-dodging signals in response to the light gray bars. These electric stimulations mimicked the mechanical stimuli of a collision. The findings further showed that combining visual and mechanical stimuli is required for associative learning in jellyfish and that the rhopalium serves as a learning center.

Next, the team plans to dive deeper into the cellular interactions of jellyfish nervous systems to tease apart memory formation. They also plan to further understand how the mechanical sensor in the bell works to paint a complete picture of the animal's associative learning.

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New evidence indicates patients recall death experiences after cardiac arrest

Up to an hour after their hearts had stopped, some patients revived by cardiopulmonary resuscitation (CPR) had clear memories afterward of experiencing death and had brain patterns while unconscious linked to thought and memory, report investigators in the journal Resuscitation, published by Elsevier.

In a study led by researchers at NYU Grossman School of Medicine, in cooperation with 25 mostly US and British hospitals, some survivors of cardiac arrest described lucid death experiences that occurred while they were seemingly unconscious. Despite immediate treatment, fewer than 10% of the 567 patients studied, who received CPR in the hospital, recovered sufficiently to be discharged. Four in 10 of patients who survived, however, recalled some degree of consciousness during CPR not captured by standard measures.

The study also found that in a subset of these patients, who received brain monitoring, nearly 40% had brain activity that returned to normal, or nearly normal, from a "flatline" state, at points even an hour into CPR. As captured by EEG, a technology that records brain activity with electrodes, the patients saw spikes in the gamma, delta, theta, alpha, and beta waves associated with higher mental function.

Survivors have long reported having heightened awareness and powerful, lucid experiences, say the study authors. These have included a perception of separation from the body, observing events without pain or distress, and a meaningful evaluation of their actions and relationships. This new work found these experiences of death to be different from hallucinations, delusions, illusions, dreams, or CPR-induced consciousness.

The study authors hypothesize that the "flatlined," dying brain removes natural inhibitory (braking) systems. These processes, known collectively as disinhibition, may open access to "new dimensions of reality," they say, including lucid recall of all stored memories from early childhood to death, evaluated from the perspective of morality. While no one knows the evolutionary purpose of this phenomenon, it "opens the door to a systematic exploration of what happens when a person dies."

Senior study author Sam Parnia, MD, PhD, associate professor in the Department of Medicine at NYU Langone Health and director of critical care and resuscitation research at NYU Langone, says, "Although doctors have long thought that the brain suffers permanent damage about 10 minutes after the heart stops supplying it with oxygen, our work found that the brain can show signs of electrical recovery long into ongoing CPR. This is the first large study to show that these recollections and brain wave changes may be signs of universal, shared elements of so-called near-death experiences."

Dr. Parnia adds, "These experiences provide a glimpse into a real, yet little understood dimension of human consciousness that becomes uncovered with death. The findings may also guide the design of new ways to restart the heart or prevent brain injuries and hold implications for transplantation."

Called the AWAreness during REsuscitation (AWARE)-II study -- it followed 567 men and women who suffered cardiac arrest during hospital stays between May 2017 and March 2020 in the United States and United Kingdom. Only hospitalized patients were enrolled to standardize the CPR and resuscitation methods used, as well as recording methods for brain activity. A subset of 85 patients received brain monitoring during CPR. Additional testimony from 126 community survivors of cardiac arrest with self-reported memories was also examined to provide greater understanding of the themes related to the recalled experience of death.

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Researchers identify the link between memory and appetite in the human brain to explain obesity

Disrupted connections between memory and appetite regulating brain circuits are directly proportional to body mass index (BMI), notably in patients who suffer from disordered or overeating that can lead to obesity, such as binge eating disorder (BED), according to new research from the Perelman School of Medicine at the University of Pennsylvania. Published today in Nature, the research notes that individuals who are obese have impaired connections between the dorsolateral hippocampus (dlHPC) and the lateral hypothalamus (LH), which may impact their ability to control or regulate emotional responses when anticipating rewarding meals or treats.

"These findings underscore that some individual's brains can be fundamentally different in regions that increase the risk for obesity," senior author, Casey Halpern, MD, an associate professor of Neurosurgery and Chief of Stereotactic and Functional Neurosurgery at Penn Medicine and the Corporal Michael J. Crescenz Veterans Affairs Medical Center. "Conditions like disordered eating and obesity are a lot more complicated than simply managing self-control and eating healthier. What these individuals need is not more willpower, but the therapeutic equivalent of an electrician that can make right these connections inside their brain."

The dlHPC is located in the region of the brain that processes memory, and the LH is in the region of the brain that is responsible for keeping the body in a stable state, called homeostasis. Previous research has found an association with loss of function in the human hippocampus in individuals with obesity and related disordered eating, like BED. However, outside of imaging techniques such as magnetic resonance imaging (MRI), the role of the hippocampus has been difficult to study in humans with obesity and related eating disorders.

In this study, researchers were able to evaluate patients whose brains were already being monitored electrically in the Epilepsy Monitoring Unit. Researchers monitored brain activity as patients anticipated and then received a sweet treat (a chocolate milkshake). They found that both the dlHPC and the LH activated simultaneously when participants anticipated receiving the rewarding meal. These researchers confirmed using stimulation techniques pioneered by coauthors, Kai Miller, MD, PhD, and Dora Hermes Miller, PhD, from Mayo Clinic, that this specific zone of the hippocampus, the dlHPC, and LH exhibited extremely strong connectivity, as well.

In individuals with obesity, researchers found that the impairment of this hypothalamus-hippocampus circuit was directly proportional to their BMI. That is, in participants with a high BMI, the connection was even more disturbed.

To further validate the connection, Halpern's team used a technique called "brain clearing," to analyze brain tissue. The technique revealed melanin-concentrating hormone, a hormone known to regulate feeding behavior that is produced in the LH. They found the presence of MCH in the dlHPC, and nowhere else, confirming a link between the two regions.

"The hippocampus has never been targeted to treat obesity, or the disordered eating that can sometimes cause obesity," said Halpern. "We hope to be able to use this research to both identify which individuals who are likely to develop obesity later in life, and to develop novel therapies -- both invasive and not -- to help improve function of this critical circuit that seems to go awry in patients who are obese."

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New study links brain waves directly to memory

Neurons produce rhythmic patterns of electrical activity in the brain. One of the unsettled questions in the field of neuroscience is what primarily drives these rhythmic signals, called oscillations. University of Arizona researchers have found that simply remembering events can trigger them, even more so than when people are experiencing the actual event.

The researchers, whose findings are published in the journal Neuron, specifically focused on what are known as theta oscillations, which emerge in the brain's hippocampus region during activities like exploration, navigation and sleep. The hippocampus plays a crucial role in the brain's ability to remember the past.

Prior to this study, it was believed that the external environment played a more important role in driving theta oscillations, said Arne Ekstrom, professor of cognition and neural systems in the UArizona Department of Psychology and senior author of the study. But Ekstrom and his collaborators found that memory generated in the brain is the main driver of theta activity.

"Surprisingly, we found that theta oscillations in humans are more prevalent when someone is just remembering things, compared to experiencing events directly," said lead study author Sarah Seger, a graduate student in the Department of Neuroscience.

The results of the study could have implications for treating patients with brain damage and cognitive impairments, including patients who have experienced seizures, stroke and Parkinson's disease, Ekstrom said. Memory could be used to create stimulations from within the brain and drive theta oscillations, which could potentially lead to improvements in memory over time, he said.

UArizona researchers collaborated on the study with researchers from the University of Texas Southwestern Medical Center in Dallas, including neurosurgeon Dr. Brad Lega and research technician Jennifer Kriegel. The researchers recruited 13 patients who were being monitored at the center in preparation for epilepsy surgery. As part of the monitoring, electrodes were implanted in the patients' brains for detecting occasional seizures. The researchers recorded the theta oscillations in the hippocampus of the brain.

The patients participated in a virtual reality experiment, in which they were given a joystick to navigate to shops in a virtual city on a computer. When they arrived at the correct destination, the virtual reality experiment was paused. The researchers asked the participants to imagine the location at which they started their navigation and instructed them to mentally navigate the route they just passed through. The researchers then compared theta oscillations during initial navigation to participants' subsequent recollection of the route.

During the actual navigation process using the joystick, the oscillations were less frequent and shorter in duration compared to oscillations that occurred when participants were just imagining the route. So, the researchers conclude that memory is a strong driver of theta oscillations in humans.

One way to compensate for impaired cognitive function is by using cognitive training and rehabilitation, Ekstrom said.

"Basically, you take a patient who has memory impairments, and you try to teach them to be better at memory," he said.

In the future, Ekstrom is planning to conduct this research in freely walking patients as opposed to patients in beds and find how freely navigating compares to memory with regard to brain oscillations.

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Sweet smell of success: Simple fragrance method produces major memory boost

When a fragrance wafted through the bedrooms of older adults for two hours every night for six months, memories skyrocketed. Participants in this study by University of California, Irvine neuroscientists reaped a 226% increase in cognitive capacity compared to the control group. The researchers say the finding transforms the long-known tie between smell and memory into an easy, non-invasive technique for strengthening memory and potentially deterring dementia.

The team's study appears in Frontiers in Neuroscience.

The project was conducted through the UCI Center for the Neurobiology of Learning & Memory. It involved men and women aged 60 to 85 without memory impairment. All were given a diffuser and seven cartridges, each containing a single and different natural oil. People in the enriched group received full-strength cartridges. Control group participants were given the oils in tiny amounts. Participants put a different cartridge into their diffuser each evening prior to going to bed, and it activated for two hours as they slept.

People in the enriched group showed a 226% increase in cognitive performance compared to the control group, as measured by a word list test commonly used to evaluate memory. Imaging revealed better integrity in the brain pathway called the left uncinate fasciculus. This pathway, which connects the medial temporal lobe to the decision-making prefrontal cortex, becomes less robust with age. Participants also reported sleeping more soundly.

Scientists have long known that the loss of olfactory capacity, or ability to smell, can predict development of nearly 70 neurological and psychiatric diseases. These include Alzheimer's and other dementias, Parkinson's, schizophrenia and alcoholism. Evidence is emerging about a link between smell loss due to COVID and ensuing cognitive decrease. Researchers have previously found that exposing people with moderate dementia to up to 40 different odors twice a day over a period of time boosted their memories and language skills, eased depression and improved their olfactory capacities. The UCI team decided to try turning this knowledge into an easy and non-invasive dementia-fighting tool.

"The reality is that over the age of 60, the olfactory sense and cognition starts to fall off a cliff," said Michael Leon, professor of neurobiology & behavior and a CNLM fellow. "But it's not realistic to think people with cognitive impairment could open, sniff and close 80 odorant bottles daily. This would be difficult even for those without dementia."

The study's first author, project scientist Cynthia Woo, said: "That's why we reduced the number of scents to just seven, exposing participants to just one each time, rather than the multiple aromas used simultaneously in previous research projects. By making it possible for people to experience the odors while sleeping, we eliminated the need to set aside time for this during waking hours every day."

The researchers say the results from their study bear out what scientists learned about the connection between smell and memory.

"The olfactory sense has the special privilege of being directly connected to the brain's memory circuits," said Michael Yassa, professor and James L. McGaugh Chair in the Neurobiology of Learning & Memory. The director of CNLM, he served as collaborating investigator. "All the other senses are routed first through the thalamus. Everyone has experienced how powerful aromas are in evoking recollections, even from very long ago. However, unlike with vision changes that we treat with glasses and hearing aids for hearing impairment, there has been no intervention for the loss of smell."

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Genes for learning and memory are 650 million years old

A team of scientists led by researchers from the University of Leicester have discovered that the genes required for learning, memory, aggression and other complex behaviours originated around 650 million years ago.

The findings led by Dr Roberto Feuda, from the Neurogenetic group in the Department of Genetics and Genome Biology and other colleagues from the University of Leicester and the University of Fribourg (Switzerland), have now been published in Nature Communications.

Dr Feuda said: "We've known for a long time that monoamines like serotonin, dopamine and adrenaline act as neuromodulators in the nervous system, playing a role in complex behaviour and functions like learning and memory, as well as processes such as sleep and feeding.

"However, less certain was the origin of the genes required for the production, detection, and degradation of these monoamines. Using the computational methods, we reconstructed the evolutionary history of these genes and show that most of the genes involved in monoamine production, modulation, and reception originated in the bilaterian stem group.

"This finding has profound implications on the evolutionary origin of complex behaviours such as those modulated by monoamines we observe in humans and other animals."

The authors suggest that this new way to modulate neuronal circuits might have played a role in the Cambrian Explosion -- known as the Big Bang -- which gave rise to the largest diversification of life for most major animal groups alive today by providing flexibility of the neural circuits to facilitate the interaction with the environment.

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Multivitamin improves memory in older adults, study finds

Taking a daily multivitamin supplement can slow age-related memory decline, finds a large study led by researchers at Columbia University and Brigham and Women's Hospital/Harvard.

"Cognitive aging is a top health concern for older adults, and this study suggests that there may be a simple, inexpensive way to help older adults slow down memory decline," says study leader Adam M. Brickman, PhD, professor of neuropsychology at Columbia University Vagelos College of Physicians and Surgeons.

Many older people take vitamins or dietary supplements under the assumption that they will help maintain general health. But studies that have tested whether they improve memory and brain function have been mixed, and very few large-scale, randomized trials have been done.

Study methods

In the current study, more than 3,500 adults (mostly non-Hispanic white) over age 60 were randomly assigned to take a daily multivitamin supplement or placebo for three years. At the end of each year, participants performed a series of online cognitive assessments at home designed to test memory function of the hippocampus, an area of the brain that is affected by normal aging. The COSMOS-Web study is part of a large clinical trial led by Brigham & Women's Hospital and Harvard called the COcoa Supplement and Multivitamin Outcomes Study (COSMOS).

By the end of the first year, memory improved for people taking a daily multivitamin, compared with those taking a placebo. The researchers estimate the improvement, which was sustained over the three-year study period, was equivalent to about three years of age-related memory decline. The effect was more pronounced in participants with underlying cardiovascular disease.

The results of the new study are consistent with another recent COSMOS study of more than 2,200 older adults that found that taking a daily multivitamin improved overall cognition, memory recall, and attention, effects that were also more pronounced in those with underlying cardiovascular disease.

"There is evidence that people with cardiovascular disease may have lower micronutrient levels that multivitamins may correct, but we don't really know right now why the effect is stronger in this group," says Brickman.

Good nutrition important for aging brain

Though the researchers did not look at whether any specific component of the multivitamin supplement was linked to the improvement in memory, the findings support growing evidence that nutrition is important for optimizing brain health as we age.

"Our study shows that the aging brain may be more sensitive to nutrition than we realized, though it may not be so important to find out which specific nutrient helps slow age-related cognitive decline," says Lok-Kin Yeung, PhD, a postdoctoral researcher in Columbia's Taub Institute for Research on Alzheimer's Disease and the Aging Brain and first author of the study.

"The finding that a daily multivitamin improved memory in two separate cognition studies in the COSMOS randomized trial is remarkable, suggesting that multivitamin supplementation holds promise as a safe, accessible, and affordable approach to protecting cognitive health in older adults," says co-author JoAnn Manson, MD, chief of the Division of Preventive Medicine at Brigham and Women's Hospital.

"Supplementation of any kind shouldn't take the place of more holistic ways of getting the same micronutrients," adds Brickman. "Though multivitamins are generally safe, people should always consult a physician before taking them."

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Three or more concussions linked with worse brain function in later life

Experiencing three or more concussions is linked with worsened brain function in later life, according to major new research.

The study -- the largest of its kind -- also found having just one moderate-to-severe concussion, or traumatic brain injury (TBI), can have a long-term impact on brain function, including memory.

Led by teams at the University of Oxford and the University of Exeter, the research included data from more than 15,000 participants of the online PROTECT study, who were aged between 50 and 90 and based in the UK. They reported the severity and frequency of concussions they had experienced throughout their lives, and completed annual, computerised tests for brain function.

Published in the Journal of Neurotrauma, the paper found that people who reported three or more concussions had significantly worse cognitive function, which got successively worse with each subsequent concussion after that. Attention and completion of complex tasks were particularly affected.

Researchers say people who have had concussions should be warned of the dangers of continuing high-risk sport or work.

Lead investigator Dr Vanessa Raymont, from the University of Oxford, said: "We know that head injuries are a major risk factor for dementia, and this large-scale study gives the greatest detail to date on a stark finding -- the more times you injure your brain in life, the worse your brain function could be as you age.

"Our research indicates that people who have experienced three or more even mild episodes of concussion should be counselled on whether to continue high-risk activities. We should also encourage organisations operating in areas where head impact is more likely to consider how they can protect their athletes or employees."

The team found that participants who reported three episodes of even mild concussion throughout their lives had significantly worse attention and ability to complete complex tasks. Those who had four or more mild concussion episodes also showed worsened processing speed and working memory. Each additional reported concussion was linked to progressively worse cognitive function.

Furthermore, the researchers found that reporting even one moderate-to-severe concussion was associated with worsened attention, completion of complex tasks and processing speed capacity.

In the online PROTECT study, participants share detailed lifestyle information, and complete a suite of cognitive tests every year, for up to 25 years. This rich mine of data helps researchers understand how the brain ages, and the factors involved in maintaining a healthier brain in later life.

Dr Helen Brooker, a study co-author from the University of Exeter, said: "As our population ages, we urgently need new ways to empower people to live healthier lives in later life. This paper highlights the importance of detailed long-term studies like PROTECT in better understating head injuries and the impact to long term cognitive function, particularly as concussion has also been linked to dementia. We're learning that life events that might seem insignificant, life experiencing a mild concussion, can have an impact on the brain. Our findings indicate that cognitive rehabilitation should focus on key functions such as attention and completion of complex tasks, which we found to be susceptible to long-term damage."

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COVID-19 infections increase risk of long-term brain problems

If you've had COVID-19, it may still be messing with your brain. Those who have been infected with the virus are at increased risk of developing a range of neurological conditions in the first year after the infection, new research shows. Such complications include strokes, cognitive and memory problems, depression, anxiety and migraine headaches, according to a comprehensive analysis of federal health data by researchers at Washington University School of Medicine in St. Louis and the Veterans Affairs St. Louis Health Care system.

Additionally, the post-COVID brain is associated with movement disorders, from tremors and involuntary muscle contractions to epileptic seizures, hearing and vision abnormalities, and balance and coordination difficulties as well as other symptoms similar to what is experienced with Parkinson's disease.

The findings are published Sept. 22 in Nature Medicine.

"Our study provides a comprehensive assessment of the long-term neurologic consequences of COVID-19," said senior author Ziyad Al-Aly, MD, a clinical epidemiologist at Washington University. "Past studies have examined a narrower set of neurological outcomes, mostly in hospitalized patients. We evaluated 44 brain and other neurologic disorders among both nonhospitalized and hospitalized patients, including those admitted to the intensive care unit. The results show the devastating long-term effects of COVID-19. These are part and parcel of long COVID. The virus is not always as benign as some people think it is."

Overall, COVID-19 has contributed to more than 40 million new cases of neurological disorders worldwide, Al-Aly said.

Other than having a COVID infection, specific risk factors for long-term neurological problems are scarce. "We're seeing brain problems in previously healthy individuals and those who have had mild infections," Al-Aly said. "It doesn't matter if you are young or old, female or male, or what your race is. It doesn't matter if you smoked or not, or if you had other unhealthy habits or conditions."

Few people in the study were vaccinated for COVID-19 because the vaccines were not yet widely available during the time span of the study, from March 2020 through early January 2021. The data also predates delta, omicron and other COVID variants.

A previous study in Nature Medicine led by Al-Aly found that vaccines slightly reduce -- by about 20% -- the risk of long-term brain problems. "It is definitely important to get vaccinated but also important to understand that they do not offer complete protection against these long-term neurologic disorders," Al-Aly said.

The researchers analyzed about 14 million de-identified medical records in a database maintained by the U.S. Department of Veterans Affairs, the nation's largest integrated health-care system. Patients included all ages, races and sexes.

They created a controlled data set of 154,000 people who had tested positive for COVID-19 sometime from March 1, 2020, through Jan. 15, 2021, and who had survived the first 30 days after infection. Statistical modeling was used to compare neurological outcomes in the COVID-19 data set with two other groups of people not infected with the virus: a control group of more than 5.6 million patients who did not have COVID-19 during the same time frame; and a control group of more than 5.8 million people from March 2018 to December 31, 2019, long before the virus infected and killed millions across the globe.

The researchers examined brain health over a year-long period. Neurological conditions occurred in 7% more people with COVID-19 compared with those who had not been infected with the virus. Extrapolating this percentage based on the number of COVID-19 cases in the U.S., that translates to roughly 6.6 million people who have suffered brain impairments associated with the virus.

Memory problems -- colloquially called brain fog -- are one of the most common brain-related, long-COVID symptoms. Compared with those in the control groups, people who contracted the virus were at a 77% increased risk of developing memory problems. "These problems resolve in some people but persist in many others," Al-Aly said. "At this point, the proportion of people who get better versus those with long-lasting problems is unknown."

Interestingly, the researchers noted an increased risk of Alzheimer's disease among those infected with the virus. There were two more cases of Alzheimer's per 1,000 people with COVID-19 compared with the control groups. "It's unlikely that someone who has had COVID-19 will just get Alzheimer's out of the blue," Al-Aly said. "Alzheimer's takes years to manifest. But what we suspect is happening is that people who have a predisposition to Alzheimer's may be pushed over the edge by COVID, meaning they're on a faster track to develop the disease. It's rare but concerning."

Also compared to the control groups, people who had the virus were 50% more likely to suffer from an ischemic stroke, which strikes when a blood clot or other obstruction blocks an artery's ability to supply blood and oxygen to the brain. Ischemic strokes account for the majority of all strokes, and can lead to difficulty speaking, cognitive confusion, vision problems, the loss of feeling on one side of the body, permanent brain damage, paralysis and death.

"There have been several studies by other researchers that have shown, in mice and humans, that SARS-CoV-2 can attack the lining of the blood vessels and then then trigger a stroke or seizure," Al-Aly said. "It helps explain how someone with no risk factors could suddenly have a stroke."

Overall, compared to the uninfected, people who had COVID-19 were 80% more likely to suffer from epilepsy or seizures, 43% more likely to develop mental health disorders such as anxiety or depression, 35% more likely to experience mild to severe headaches, and 42% more likely to encounter movement disorders. The latter includes involuntary muscle contractions, tremors and other Parkinson's-like symptoms.

COVID-19 sufferers were also 30% more likely to have eye problems such as blurred vision, dryness and retinal inflammation; and they were 22% more likely to develop hearing abnormalities such as tinnitus, or ringing in the ears.

"Our study adds to this growing body of evidence by providing a comprehensive account of the neurologic consequences of COVID-19 one year after infection," Al-Aly said.

Read more at Science Daily

Working memory depends on reciprocal interactions across the brain

How does the brain keep in mind a phone number before dialling? Working memory is an essential component of cognition, allowing the brain to remember information temporarily and use it to guide future behaviour. While many previous studies have revealed the involvement of several brain areas, until now it remained unclear as to how these multiple regions interact to represent and maintain working memory.

In a new study, published today in Nature, neuroscientists at the Sainsbury Wellcome Centre at UCL investigated the reciprocal interactions between two brain regions that represent visual working memory in mice. The team found that communication between these two loci of working memory, parietal cortex and premotor cortex, was co-dependent on instantaneous timescales.

"There are many different types of working memory and over the past 40 years scientists have been trying to work out how these are represented in the brain. Sensory working memory in particular has been challenging to study, as during standard laboratory tasks many other processes are happening simultaneously, such as timing, motor preparation, and reward expectation," said Dr Ivan Voitov, Research Fellow in the Mrsic-Flogel lab and first author on the paper.

To overcome this challenge, the SWC researchers compared a working memory-dependent task with a simpler working memory-independent task. In the working memory task, mice were given a sensory stimulus followed by a delay and then had to match the next stimulus to the one they saw prior to the delay. This meant that during the delay the mice needed a representation in their working memory of the first stimulus to succeed in the task and receive a reward. In contrast, in the working memory-independent task, the decision the mice made on the secondary stimulus was unrelated to the first stimulus.

By contrasting these two tasks, the researchers were able to observe the part of the neural activity that was dependent on working memory as opposed to the natural activity that was just related to the task environment. They found that most neural activity was unrelated to working memory, and instead working memory representations were embedded within 'high-dimensional' modes of activity, meaning that only small fluctuations around the mean firing of individual cells were together carrying the working memory information.

To understand how these representations are maintained in the brain, the neuroscientists used a technique called optogenetics to selectively silence parts of the brain during the delay period and observed the disruption to what the mice were remembering. Interestingly, they found that silencing working memory representations in either one of the parietal or premotor cortical areas led to similar deficits in the mice's ability to remember the previous stimulus, implying that these representations were instantaneously co-dependent on each other during the delay.

To test this hypothesis, the researchers disrupted one area while recording the activity that was being communicated back to it by the other area. When they disrupted parietal cortex, the activity that was being communicated by premotor cortex to parietal cortex was largely unchanged in terms of average activity. However, the representation of working memory activity specifically was disrupted. This was also true in the reverse experiment, when they disrupted premotor cortex and looked at parietal cortex and also observed working memory-specific disruption of cortical-cortical communication.

"By recording from and manipulating long-range circuits in the cerebral cortex, we uncovered that working memory resides within co-dependent activity patterns in cortical areas that are interconnected, thereby maintaining working memory through instantaneous reciprocal communication," said Professor Tom Mrsic-Flogel, Director of the Sainsbury Wellcome Centre and co-author on the paper.

The next step for the researchers is to look for patterns of activity that are shared between these areas. They also plan to study more sophisticated working memory tasks that modulate the specific information that is being stored in working memory in addition to its strength. For this, the neuroscientists will use interleaved distractors containing sensory information that bias what the mouse thinks is the next target. Such experiments will allow them to develop a more nuanced understanding of working memory representations.

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Paper wasps form abstract concept of 'same' and 'different'

In a series of studies over more than 20 years, University of Michigan evolutionary biologist Elizabeth Tibbetts and her colleagues have demonstrated that paper wasps, despite their tiny brains, have an impressive capacity to learn, remember and make social distinctions about others.

The researchers showed that paper wasps recognize individuals of their species by variations in their facial markings and that they behave more aggressively toward wasps with unfamiliar markings.

They established that paper wasps have surprisingly long memories and base their actions on what they remember of previous social interactions with other wasps. And they provided the first evidence of transitive inference -- a behavior that resembles logical reasoning -- in a nonvertebrate animal, the lowly paper wasp.

Now, Tibbetts and her students are reporting the first evidence that paper wasps can form abstract concepts. Strikingly, the wasps were also able to transfer what they learned through visual training into a different sensory modality: the sense of smell.

The study used laboratory tasks to test whether paper wasps (Polistes fuscatus) could learn and apply one of the most basic abstract concepts: the idea of sameness and difference.

The wasps were trained to distinguish between pairs of visual or olfactory stimuli (two colored bits of paper, two photos of wasp faces, or two chemical odors) that were either identical or different. One pair of stimuli was associated with a mild but unpleasant electrical shock, the other was not.

Then the stinging insects were exposed to novel pairs of stimuli (either identical or different) and tested on their ability to avoid an electric shock by selecting the "correct" pair -- the one associated with safety.

The previously trained wasps made the correct choice more than 80% of the time, according to the researchers. The team's findings were published online July 20 in the journal Proceedings of the Royal Society B.

"Our findings show the wasps learned the general concept of sameness and difference and applied it to new samples and new types of stimuli," said Tibbetts, a professor in the U-M Department of Ecology and Evolutionary Biology.

"Abstract concepts are thought to be associated with high levels of cognitive sophistication, so there has been much interest in which species can form and use them. This is the first time anyone has shown that wasps can form abstract concepts."

Historically, only primates were thought to be capable of same-different concept learning. But subsequent research found evidence of same-different concepts in many animals, including crows, pigeons, parrots, dolphins, ducklings and honeybees.

Now, the U-M researchers are adding paper wasps to the list. The first author of the Proceedings of the Royal Society B study is Chloe Weise, a former U-M master's student who graduated this spring.

"Concept learning is a cornerstone of challenging tasks like language, analogy and consciousness," Weise said. "Our results add to a growing body of evidence that the miniature nervous systems of insects do not limit sophisticated behaviors."

For the study, female paper wasps were collected on their nests in areas surrounding Ann Arbor, Michigan. The wasps and their nests were housed in the lab and were given water, sugar and waxworms for food.

During training and testing, individual wasps were placed inside a small balsa wood-and-plexiglass chamber to determine whether they could learn and apply same-different concepts.

The wasps were trained and tested using a method called the simultaneous two-item same-different task. Three types of stimuli were used in the study: colored paper, images of wasp faces and the scents of chemicals called alkenes, which resemble the odors that wasps use to identify nestmates.

The laboratory tests showed that wasps trained with visual stimuli were able to apply the concept of sameness and difference to olfactory stimuli.

"Remarkably, wasps applied the concept of sameness and difference across sensory modalities, as they transferred concepts learned in the visual domain to the odor domain," Weise said. "Therefore, our results illustrate that Polistes are able to master abstract interrelationships between stimuli."

Paper wasps are the second invertebrate shown to form same-different concepts, after honeybees. Paper wasps and honeybees have considerably smaller brains (fewer than 1 million neurons) than vertebrates known to form same-different concepts. Pigeons, for example, have brains with 310 million neurons, and macaque brains have 6 billion neurons.

Interestingly, paper wasps in this study achieved more than 80% correct choices after training involving just eight trials with eight stimulus pairs, while pigeons require 100 unique stimuli and thousands of trials to learn same-different concepts, according to Tibbetts.

The paper wasps used in the current study may have been more adept than pigeons at forming concepts because they were trained with different methods, including the use of biologically relevant stimuli, Tibbetts said.

"We trained and tested wasps using wasp face images, colors and odors," she said. "All three types of stimuli are important in wild wasp behavior."

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A rare discovery of long-term memory in wild frog-eating bats

Frog-eating bats trained by researchers to associate a phone ringtone with a tasty treat were able to remember what they learned for up to four years in the wild, new research has found.

The study acquainted 49 bats with a series of ringtones that attracted their attention, and trained them to associate flying toward just one of the tones with a reward: a baitfish snack.

Between one and four years later, eight of those bats were recaptured and exposed again to the food-related ringtone. All of them flew toward the sound, and six flew all the way to the speaker and grabbed the food reward, meaning they expected to find food. Control bats without previous training on the sounds were comparatively unmoved by the exposure to the unfamiliar tones.

"I was surprised -- I went into this thinking that at least a year would be a reasonable time for them to remember, given all the other things they need to know and given that long-term memory does have real costs. Four years strikes me as a long time to hold on to a sound that you might never hear again," said lead author May Dixon, a postdoctoral scholar in evolution, ecology and organismal biology at The Ohio State University.

Dixon led this study at the Smithsonian Tropical Research Institute in Panama while she was a graduate student at the University of Texas at Austin.

"The environment that previous generations experienced can be extremely different from the environment an animal is born into -- and it may also change throughout an animal's life," she said. "Trying to figure out how animals use learning and memory is one way to figure out how they're going to make it in a life full of change in the modern world."

The study is published today (June 20, 2022) in Current Biology.

In the first phase, individual frog-eating bats captured for a series of cognition tests were exposed to a highly attractive sound in the lab: the mating call of the male túngara frog, one of this species of bats' preferred prey. Flying to that sound was rewarded with a piece of baitfish placed on mesh above the speaker.

Over time, the sound was mingled with and gradually replaced by a ringtone, but the reward was the same. Researchers then introduced three other ringtones, none of which was connected to a food reward. Bats were trained to discern the differences and eventually no longer flew toward the unrewarded sounds. Each bat secured at least 40 snacks by flying to the trained ringtone over 11 to 27 days. All bats were microchipped and returned to the wild.

Beginning a year later and for three additional years, Dixon captured bats and identified eight from the initial trial by their microchips. In a follow-up test of their response to the original rewarded ringtone, all eight trained bats quickly flew to the sound and were able to tell the difference between that ringtone and a new, steady tone, though many of the bats did fly to an unrewarded sound from the initial training.

When 17 untrained bats were exposed to these sounds, they mostly twitched their ears in response to the sounds, but didn't fly toward them.

"The study taught us a lot because there are relatively few studies of long-term memory in wild animals and we don't have systematic understanding of long-term memories in nature yet," Dixon said. "If we can collect additional data on different species of bats, we could pick this apart and see what life histories select for long memories."

The paper lists 39 previous studies that have documented memory in species ranging from fish, birds and bats to goats and primates. Some of the longest of those experiments -- documenting memory in sea lions for 10 years, tortoises for nine years and dolphins for 20 years -- were all conducted on animals that lived in captivity the entire time.

"Being able to study memory in the wild is important," said study co-author Gerald Carter, assistant professor of evolution, ecology and organismal biology at Ohio State. "You can't necessarily extrapolate from the wealth of data we have on animals in the lab to what they're facing in the wild, where there are many more things they have to remember. The environment is different and the brain is different in the wild versus captivity."

Despite the human tendency to assume a long memory gives our species the intelligence advantage, nature shows us that memory flexibility -- also called adaptive forgetting -- may be important for survival.

"It's not always true that being the smartest or having the longest memory is actually advantageous. Research has shown that fruitflies selected for improved memories can't compete as well against other fruitflies," Dixon said. "Just because it's useful for humans to be so smart and have such good memories doesn't necessarily mean it's going to be the best thing for other animals.

Read more at Science Daily

Study examines why the memory of fear is seared into our brains

Experiencing a frightening event is likely something you'll never forget. But why does it stay with you when other kinds of occurrences become increasingly difficult to recall with the passage of time?

A team of neuroscientists from the Tulane University School of Science and Engineering and Tufts University School of Medicine have been studying the formation of fear memories in the emotional hub of the brain -- the amygdala -- and think they have a mechanism.

In a nutshell, the researchers found that the stress neurotransmitter norepinephrine, also known as noradrenaline, facilitates fear processing in the brain by stimulating a certain population of inhibitory neurons in the amygdala to generate a repetitive bursting pattern of electrical discharges. This bursting pattern of electrical activity changes the frequency of brain wave oscillation in the amygdala from a resting state to an aroused state that promotes the formation of fear memories.

Published recently in Nature Communications, the research was led by Tulane cell and molecular biology professor Jeffrey Tasker, the Catherine and Hunter Pierson Chair in Neuroscience, and his PhD student Xin Fu.

Tasker used the example of an armed robbery. "If you are held up at gunpoint, your brain secretes a bunch of the stress neurotransmitter norepinephrine, akin to an adrenaline rush," he said.

"This changes the electrical discharge pattern in specific circuits in your emotional brain, centered in the amygdala, which in turn transitions the brain to a state of heightened arousal that facilitates memory formation, fear memory, since it's scary. This is the same process, we think, that goes awry in PTSD and makes it so you cannot forget traumatic experiences."

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Scientists identify how the brain links memories

Our brains rarely record single memories -- instead, they store memories into groups so that the recollection of one significant memory triggers the recall of others connected by time. As we age, however, our brains gradually lose this ability to link related memories.

Now UCLA researchers have discovered a key molecular mechanism behind memory linking. They've also identified a way to restore this brain function in middle-aged mice -- and an FDA-approved drug that achieves the same thing.

Published in Nature, the findings suggest a new method for strengthening human memory in middle age and a possible early intervention for dementia.

"Our memories are a huge part of who we are," explained Alcino Silva, a distinguished professor of neurobiology and psychiatry at the David Geffen School of Medicine at UCLA. "The ability to link related experiences teaches how to stay safe and operate successfully in the world."

A bit of Biology 101: cells are studded with receptors. To enter a cell, a molecule must latch onto its matching receptor, which operates like a doorknob to provide access inside.

The UCLA team focused on a gene called CCR5 that encodes the CCR5 receptor -- the same one that HIV hitches a ride on to infect the brain cell and cause memory loss in AIDS patients.

Silva's lab demonstrated in earlier research that CCR5 expression reduced memory recall.

In the current study, Silva and his colleagues discovered a central mechanism underlying mice's ability to link their memories of two different cages. A tiny microscope opened a window into the animals' brains, enabling the scientists to observe neurons firing and creating new memories.

Boosting CCR5 gene expression in the brains of middle-aged mice interfered with memory linking. The animals forgot the connection between the two cages.

When the scientists deleted the CCR5 gene in the animals, the mice were able to link memories that normal mice could not.

Silva had previously studied the drug, maraviroc, which the U.S. Food and Drug Administration approved in 2007 for the treatment of HIV infection. His lab discovered that maraviroc also suppressed CCR5 in the brains of mice.

"When we gave maraviroc to older mice, the drug duplicated the effect of genetically deleting CCR5 from their DNA," said Silva, a member of the UCLA Brain Research Institute. "The older animals were able to link memories again."

The finding suggests that maraviroc could be used off-label to help restore middle-aged memory loss, as well as reverse the cognitive deficits caused by HIV infection.

"Our next step will be to organize a clinical trial to test maraviroc's influence on early memory loss with the goal of early intervention," said Silva. "Once we fully understand how memory declines, we possess the potential to slow down the process."

Which begs the question: why does the brain need a gene that interferes with its ability to link memories?

Read more at Science Daily

A brain circuit in the thalamus helps us hold information in mind

As people age, their working memory often declines, making it more difficult to perform everyday tasks. One key brain region linked to this type of memory is the anterior thalamus, which is primarily involved in spatial memory -- memory of our surroundings and how to navigate them.

In a study of mice, MIT researchers have identified a circuit in the anterior thalamus that is necessary for remembering how to navigate a maze. The researchers also found that this circuit is weakened in older mice, but enhancing its activity greatly improves their ability to run the maze correctly.

This region could offer a promising target for treatments that could help reverse memory loss in older people, without affecting other parts of the brain, the researchers say.

"By understanding how the thalamus controls cortical output, hopefully we could find more specific and druggable targets in this area, instead of generally modulating the prefrontal cortex, which has many different functions," says Guoping Feng, the James W. and Patricia T. Poitras Professor in Brain and Cognitive Sciences at MIT, a member of the Broad Institute of Harvard and MIT, and the associate director of the McGovern Institute for Brain Research at MIT.

Feng is the senior author of the study, which appears today in the Proceedings of the National Academy of Sciences. Dheeraj Roy, a NIH K99 Awardee and a McGovern Fellow at the Broad Institute, and Ying Zhang, a J. Douglas Tan Postdoctoral Fellow at the McGovern Institute, are the lead authors of the paper.

Spatial memory

The thalamus, a small structure located near the center of the brain, contributes to working memory and many other executive functions, such as planning and attention. Feng's lab has recently been investigating a region of the thalamus known as the anterior thalamus, which has important roles in memory and spatial navigation.

Previous studies in mice have shown that damage to the anterior thalamus leads to impairments in spatial working memory. In humans, studies have revealed age-related decline in anterior thalamus activity, which is correlated with lower performance on spatial memory tasks.

The anterior thalamus is divided into three sections: ventral, dorsal, and medial. In a study published last year, Feng, Roy and Zhang studied the role of the anterodorsal (AD) thalamus and anteroventral (AV) thalamus in memory formation. They found that the AD thalamus is involved in creating mental maps of physical spaces, while the AV thalamus helps the brain to distinguish these memories from other memories of similar spaces.

In their new study, the researchers wanted to look more deeply at the AV thalamus, exploring its role in a spatial working memory task. To do that, they trained mice to run a simple T-shaped maze. At the beginning of each trial, the mice ran until they reached the T. One arm was blocked off, forcing them to run down the other arm. Then, the mice were placed in the maze again, with both arms open. The mice were rewarded if they chose the opposite arm from the first run. This meant that in order to make the correct decision, they had to remember which way they had turned on the previous run.

As the mice performed the task, the researchers used optogenetics to inhibit activity of either AV or AD neurons during three different parts of the task: the sample phase, which occurs during the first run; the delay phase, while they are waiting for the second run to begin; and the choice phase, when the mice make their decision which way to turn during the second run.

The researchers found that inhibiting AV neurons during the sample or choice phases had no effect on the mice's performance, but when they suppressed AV activity during the delay phase, which lasted 10 seconds or longer, the mice performed much worse on the task.

This suggests that the AV neurons are most important for keeping information in mind while it is needed for a task. In contrast, inhibiting the AD neurons disrupted performance during the sample phase but had little effect during the delay phase. This finding was consistent with the research team's earlier study showing that AD neurons are involved in forming memories of a physical space.

"The anterior thalamus in general is a spatial learning region, but the ventral neurons seem to be needed in this maintenance period, during this short delay," Roy says. "Now we have two subdivisions within the anterior thalamus: one that seems to help with contextual learning and the other that actually helps with holding this information."

Age-related decline

The researchers then tested the effects of age on this circuit. They found that older mice (14 months) performed worse on the T-maze task and their AV neurons were less excitable. However, when the researchers artificially stimulated those neurons, the mice's performance on the task dramatically improved.

Another way to enhance performance in this memory task is to stimulate the prefrontal cortex, which also undergoes age-related decline. However, activating the prefrontal cortex also increases measures of anxiety in the mice, the researchers found.

"If we directly activate neurons in medial prefrontal cortex, it will also elicit anxiety-related behavior, but this will not happen during AV activation," Zhang says. "That is an advantage of activating AV compared to prefrontal cortex."

If a noninvasive or minimally invasive technology could be used to stimulate those neurons in the human brain, it could offer a way to help prevent age-related memory decline, the researchers say. They are now planning to perform single-cell RNA sequencing of neurons of the anterior thalamus to find genetic signatures that could be used to identify cells that would make the best targets.

Read more at Science Daily

Cases of cognitive decline in older people more than doubles in ten years

The researchers set out to see if there had been an increase in the numbers of older people who were reporting their first concerns about memory loss or cognitive decline to their doctor and what their chances of developing dementia were after consultation.

The study, published today in Clinical Epidemiology, looked at data from more than 1.3m adults aged between 65 and 99 years old, taken between 2009 and the end of 2018. The researchers identified 55,941 adults who had spoken to their GP about memory concerns and 14,869 people who had a record of cognitive decline.

For every 1,000 people that were observed for one year in 2009, there was one new case of cognitive decline being recorded. By 2018, for every 1,000 people that were observed for one year, there were three new cases of cognitive decline being recorded.

Lead author and PhD candidate Brendan Hallam (UCL Epidemiology & Health Care) said: "This is an important study which sheds new light on how prevalent memory concerns and cognitive decline are among the older generation in the UK and how likely these symptoms might progress to a dementia diagnosis.

"The study showed that while memory concern rates had remained stable, incidence of cognitive decline, a step beyond memory concern, had more than doubled between 2009 and 2018.

"There has been a drive in the past decade to encourage people to seek help earlier from their doctors if they are worried about their memory and we found that among those over 80, women and people living in more deprived areas were more likely to have a record of memory concern or cognitive decline, and their symptoms were more likely to progress to dementia diagnosis."

The study also showed that within three years of following up a person from the date when the doctor reported a memory concern, 46% of people would go on to develop dementia. For people with cognitive decline, 52% would go on to develop dementia.

Co-author, Professor Kate Walters (UCL Epidemiology & Health Care) explained: "People who have been noted in their health records as having concerns about their memory are at just under 50% chance of developing dementia within the next three years."

Brendan Hallam also outlined "Memory concerns and cognitive decline are not only hallmark symptoms of dementia, but they also predict a high risk of developing dementia. It is important for GPs to identify people with memory concerns as soon as possible to deliver recommendations to improve memory and allow timely diagnosis of dementia."

The authors note one potential limitation of the present study is the potential variations in which GPs record memory concerns and memory decline. They also say more research is needed to better understand the discrepancy between rates of memory symptoms and cognitive decline in the general population and those recorded in primary care.

Read more at Science Daily