Neuroscience

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Posts tagged memory

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Just 30 minutes of exercise has benefits for the brain
University of Adelaide neuroscientists have discovered that just one session of aerobic exercise is enough to spark positive changes in the brain that could lead to improved memory and coordination of motor skills.
A study conducted by researchers in the University’s Robinson Research Institute has found changes in the brain that were likely to make it more “plastic” after only 30 minutes of vigorous exercise.
The study involved a small group of healthy people aged in their late 20s to early 30s who rode exercise bikes. They were monitored for changes in the brain immediately after the exercise and again 15 minutes later.
"We saw positive changes in the brain straight away, and these improvements were sustained 15 minutes after the exercise had ended," says research leader Associate Professor Michael Ridding.
"Plasticity in the brain is important for learning, memory and motor skill coordination. The more ‘plastic’ the brain becomes, the more it’s able to reorganise itself, modifying the number and strength of connections between nerve cells and different brain areas."
Associate Professor Ridding says past research has shown that regular physical activity can have positive effects on brain function and plasticity, but it was unknown whether a stand-alone session of exercise would also have similar positive effects.
"We now have evidence suggesting that it does," he says. "This exercise-related change in the brain may, in part, explain why physical activity has a positive effect on memory and higher-level functions."
Associate Professor Ridding says there is now mounting evidence that engaging in aerobic exercise positively influences brain function in many ways - at cellular and molecular levels, as well as in the brain’s architecture.
"Although this was a small sample group, it helps us to better understand the overall picture of how exercise influences the brain," he says.
"We know that plasticity is also important for recovery from brain damage, so this opens up potential therapeutic avenues for patients.
"Further research will be required to see what the possible long-term benefits could be for patients as well as healthy people."

Just 30 minutes of exercise has benefits for the brain

University of Adelaide neuroscientists have discovered that just one session of aerobic exercise is enough to spark positive changes in the brain that could lead to improved memory and coordination of motor skills.

A study conducted by researchers in the University’s Robinson Research Institute has found changes in the brain that were likely to make it more “plastic” after only 30 minutes of vigorous exercise.

The study involved a small group of healthy people aged in their late 20s to early 30s who rode exercise bikes. They were monitored for changes in the brain immediately after the exercise and again 15 minutes later.

"We saw positive changes in the brain straight away, and these improvements were sustained 15 minutes after the exercise had ended," says research leader Associate Professor Michael Ridding.

"Plasticity in the brain is important for learning, memory and motor skill coordination. The more ‘plastic’ the brain becomes, the more it’s able to reorganise itself, modifying the number and strength of connections between nerve cells and different brain areas."

Associate Professor Ridding says past research has shown that regular physical activity can have positive effects on brain function and plasticity, but it was unknown whether a stand-alone session of exercise would also have similar positive effects.

"We now have evidence suggesting that it does," he says. "This exercise-related change in the brain may, in part, explain why physical activity has a positive effect on memory and higher-level functions."

Associate Professor Ridding says there is now mounting evidence that engaging in aerobic exercise positively influences brain function in many ways - at cellular and molecular levels, as well as in the brain’s architecture.

"Although this was a small sample group, it helps us to better understand the overall picture of how exercise influences the brain," he says.

"We know that plasticity is also important for recovery from brain damage, so this opens up potential therapeutic avenues for patients.

"Further research will be required to see what the possible long-term benefits could be for patients as well as healthy people."

Filed under exercise memory plasticity physical activity brain function neuroscience science

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Dietary Flavanols Reverse Age-Related Memory Decline

Dietary cocoa flavanols—naturally occurring bioactives found in cocoa—reversed age-related memory decline in healthy older adults, according to a study led by Columbia University Medical Center (CUMC) scientists. The study, published today in the advance online issue of Nature Neuroscience, provides the first direct evidence that one component of age-related memory decline in humans is caused by changes in a specific region of the brain and that this form of memory decline can be improved by a dietary intervention.

As people age, they typically show some decline in cognitive abilities, including learning and remembering such things as the names of new acquaintances or where they parked the car or placed their keys. This normal age-related memory decline starts in early adulthood but usually does not have any noticeable impact on quality of life until people reach their fifties or sixties. Age-related memory decline is different from the often-devastating memory impairment that occurs with Alzheimer’s, in which a disease process damages and destroys neurons in various parts of the brain, including the memory circuits.

Previous work, including by the laboratory of senior author Scott A. Small, MD, had shown that changes in a specific part of the brain—the dentate gyrus—are associated with age-related memory decline. Until now, however, the evidence in humans showed only a correlational link, not a causal one. To see if the dentate gyrus is the source of age-related memory decline in humans, Dr. Small and his colleagues tested whether compounds called cocoa flavanols can improve the function of this brain region and improve memory. Flavanols extracted from cocoa beans had previously been found to improve neuronal connections in the dentate gyrus of mice.

Dr. Small is the Boris and Rose Katz Professor of Neurology (in the Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, the Sergievsky Center, and the Departments of Radiology and Psychiatry) and director of the Alzheimer’s Disease Research Center in the Taub Institute at CUMC.

A cocoa flavanol-containing test drink prepared specifically for research purposes was produced by the food company Mars, Incorporated, which also partly supported the research, using a proprietary process to extract flavanols from cocoa beans. Most methods of processing cocoa remove many of the flavanols found in the raw plant.

In the CUMC study, 37 healthy volunteers, ages 50 to 69, were randomized to receive either a high-flavanol diet (900 mg of flavanols a day) or a low-flavanol diet (10 mg of flavanols a day) for three months. Brain imaging and memory tests were administered to each participant before and after the study. The brain imaging measured blood volume in the dentate gyrus, a measure of metabolism, and the memory test involved a 20-minute pattern-recognition exercise designed to evaluate a type of memory controlled by the dentate gyrus.

“When we imaged our research subjects’ brains, we found noticeable improvements in the function of the dentate gyrus in those who consumed the high-cocoa-flavanol drink,” said lead author Adam M. Brickman, PhD, associate professor of neuropsychology at the Taub Institute.

The high-flavanol group also performed significantly better on the memory test. “If a participant had the memory of a typical 60-year-old at the beginning of the study, after three months that person on average had the memory of a typical 30- or 40-year-old,” said Dr. Small. He cautioned, however, that the findings need to be replicated in a larger study—which he and his team plan to do.    

Flavanols are also found naturally in tea leaves and in certain fruits and vegetables, but the overall amounts, as well as the specific forms and mixtures, vary widely.

The precise formulation used in the CUMC study has also been shown to improve cardiovascular health. Brigham and Women’s Hospital in Boston recently announced an NIH-funded study of 18,000 men and women to see whether flavanols can help prevent heart attacks and strokes.

The researchers point out that the product used in the study is not the same as chocolate, and they caution against an increase in chocolate consumption in an attempt to gain this effect.

Two innovations by the investigators made the study possible. One was a new information-processing tool that allows the imaging data to be presented in a single three-dimensional snapshot, rather than in numerous individual slices. The tool was developed in Dr. Small’s lab by Usman A. Khan, an MD-PhD student in the lab, and Frank A. Provenzano, a biomedical engineering graduate student at Columbia. The other innovation was a modification to a classic neuropsychological test, allowing the researchers to evaluate memory function specifically localized to the dentate gyrus. The revised test was developed by Drs. Brickman and Small.

Besides flavanols, exercise has been shown in previous studies, including those of Dr. Small, to improve memory and dentate gyrus function in younger people. In the current study, the researchers were unable to assess whether exercise had an effect on memory or on dentate gyrus activity. “Since we didn’t reach the intended VO2max (maximal oxygen uptake) target,” said Dr. Small, “we couldn’t evaluate whether exercise was beneficial in this context. This is not to say that exercise is not beneficial for cognition. It may be that older people need more intense exercise to reach VO2max levels that have therapeutic effects.”

Filed under aging memory decline flavanols dentate gyrus cognition memory neuroscience science

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(Figure 1: A magnified image of a mouse brain showing memory cells (red) that can be turned ‘on’ and ‘off’ using light delivered by a fiber optic cable (black). Credit: © Susumu Tonegawa)
Memories get the emotional switch
Memories of experiences are encoded in the brain along with contextual and emotional information such as where the experience took place and whether it was positive or negative. This allows for the formation of memory associations that might assist in survival. Just how this positive and negative encoding occurs, however, has remained unclear.
Susumu Tonegawa and colleagues from the RIKEN–MIT Center for Neural Circuit Genetics have now discovered that neurons in the hippocampus region of the brain can be artificially switched to encode memories as either positive or negative regardless of the original experience.
Tonegawa’s research team used genetic techniques to mark neurons in the dorsal dentate gyrus region of the hippocampus and the basolateral complex of the amygdala (BLA) in male mice. Memories are encoded in both these regions as specific groups of activated cells called ‘engrams’, but each region encodes the memory in slightly different ways: the BLA encodes positive and negative memory ‘valence’, while the dorsal dentate gyrus encodes contextual information such as emotion.
The genetic labeling, which involved using a light-sensitive ion channel called channelrhodopsin, was activated by the formation of either a positive memory, in this case exposure to females, or a negative memory associated with a foot shock. The cells that expressed this channel could be subsequently activated by exposure to light (Fig. 1); doing so induced aversive responses in mice that had experienced foot shocks, and appetitive responses in those that had experienced female interactions.
The researchers then used light to activate the hippocampal or BLA neurons that had been labeled during the formation of a positive memory while exposing the mice to foot shocks. The next time the animals were tested, light activation of those hippocampal neurons that had initially induced appetitive responses instead led the mice to exhibit aversive responses. However, BLA neurons could not be switched in this way, indicating that only neurons in the hippocampus have plasticity in their encoding of positive or negative memories.
The valence of hippocampal neurons, the researchers found, could be switched from both good to bad and bad to good using this technique, with the switch attributed to a change in the strength of connections between the hippocampal and BLA neurons of each engram.
The findings provide new insight into how memories can be altered after they are formed. The possibility of inducing similar changes to memory valence in humans could also offer hope of a treatment for those suffering from conditions such as post-traumatic stress disorder.

(Figure 1: A magnified image of a mouse brain showing memory cells (red) that can be turned ‘on’ and ‘off’ using light delivered by a fiber optic cable (black). Credit: © Susumu Tonegawa)

Memories get the emotional switch

Memories of experiences are encoded in the brain along with contextual and emotional information such as where the experience took place and whether it was positive or negative. This allows for the formation of memory associations that might assist in survival. Just how this positive and negative encoding occurs, however, has remained unclear.

Susumu Tonegawa and colleagues from the RIKEN–MIT Center for Neural Circuit Genetics have now discovered that neurons in the hippocampus region of the brain can be artificially switched to encode memories as either positive or negative regardless of the original experience.

Tonegawa’s research team used genetic techniques to mark neurons in the dorsal dentate gyrus region of the hippocampus and the basolateral complex of the amygdala (BLA) in male mice. Memories are encoded in both these regions as specific groups of activated cells called ‘engrams’, but each region encodes the memory in slightly different ways: the BLA encodes positive and negative memory ‘valence’, while the dorsal dentate gyrus encodes contextual information such as emotion.

The genetic labeling, which involved using a light-sensitive ion channel called channelrhodopsin, was activated by the formation of either a positive memory, in this case exposure to females, or a negative memory associated with a foot shock. The cells that expressed this channel could be subsequently activated by exposure to light (Fig. 1); doing so induced aversive responses in mice that had experienced foot shocks, and appetitive responses in those that had experienced female interactions.

The researchers then used light to activate the hippocampal or BLA neurons that had been labeled during the formation of a positive memory while exposing the mice to foot shocks. The next time the animals were tested, light activation of those hippocampal neurons that had initially induced appetitive responses instead led the mice to exhibit aversive responses. However, BLA neurons could not be switched in this way, indicating that only neurons in the hippocampus have plasticity in their encoding of positive or negative memories.

The valence of hippocampal neurons, the researchers found, could be switched from both good to bad and bad to good using this technique, with the switch attributed to a change in the strength of connections between the hippocampal and BLA neurons of each engram.

The findings provide new insight into how memories can be altered after they are formed. The possibility of inducing similar changes to memory valence in humans could also offer hope of a treatment for those suffering from conditions such as post-traumatic stress disorder.

Filed under memory hippocampus neurons dentate gyrus engrams emotion neuroscience science

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Combatting Memory Decline Among Menopausal Women Could Be the Next Research Frontier for Hypnotic Relaxation Therapy
Memory decline — a frequent complaint of menopausal women — potentially could be lessened by hypnotic relaxation therapy, say Baylor University researchers, who already have done studies showing that such therapy eases hot flashes, improves sleep and reduces stress in menopausal women.
Their review — “Memory Decline in Peri- and Post-menopausal Women: The Potential of Mind-Body Medicine to Improve Cognitive Performance” — is published in the journal Integrative Medicine Insights. October has been designated World Menopause Month by the International Menopause Society.
Initial research by Baylor, funded by the National Institutes of Health, focused on hot flashes, finding that hypnotic relaxation therapy lessened them, but “along the way, we discovered there are a lot of secondary benefits, including significantly improved sleep and mood,” said Jim R. Sliwinski, a doctoral student in the department of psychology and neuroscience in Baylor’s College of Arts & Sciences.
Co-researcher Gary Elkins, Ph.D., theorizes that sleep, mood and hot flashes associated with decreased estrogen also have a bearing on memory. Their publication, which reviews previous research by other scholars, proposes a framework for how mind-body interventions may improve memory, which could prove fruitful in doing future research.
“Memory decline may not be solely about decreased estrogen,” said Elkins, director of Baylor’s Mind-Body Medicine Research Laboratory and a professor of psychology and neuroscience.
Peri- and post-menopausal women may find mind-body therapies attractive for many reasons, among them that they do not have the side effects of medications or hormone therapy, said Elkins, author of “Relief from Hot Flashes: The Natural, Drug-Free Program to Reduce Hot Flashes, Improve Sleep and Ease Stress.”
While hormone therapy can increase estrogen, it also is associated with an increased risk of breast cancer and cardiovascular disease for some women, he said.
Researchers have noted that while memory decline can occur with aging in both men and women, women are more likely to report a greater number of memory problems, associating it with estrogen decline. Women also report more concerns about memory than pre-menopausal women do, according to several large-scale survey studies.
A factor that may impact memory is that women are dealing with increased responsibilities, stress or depression over such issues as caring for aging parents. In addition, their concern about memory problems may cause them to be more aware of memory lapses, Sliwinski said.
Even women who can safely be treated with estrogen do not necessarily have improved memory. “It sometimes even is associated with cognition problems,” he said.
Although there are questions about sleep’s specific role in forming and storing memories, researchers generally agree that consolidated sleep throughout a whole night is optimal for learning and memory.
Memory tests and scores over time with study participants — both pre-and post-menopausal — could help shed light on how menopause affects recollection, the Baylor researchers said.
(Image: Shutterstock)

Combatting Memory Decline Among Menopausal Women Could Be the Next Research Frontier for Hypnotic Relaxation Therapy

Memory decline — a frequent complaint of menopausal women — potentially could be lessened by hypnotic relaxation therapy, say Baylor University researchers, who already have done studies showing that such therapy eases hot flashes, improves sleep and reduces stress in menopausal women.

Their review — “Memory Decline in Peri- and Post-menopausal Women: The Potential of Mind-Body Medicine to Improve Cognitive Performance” — is published in the journal Integrative Medicine Insights. October has been designated World Menopause Month by the International Menopause Society.

Initial research by Baylor, funded by the National Institutes of Health, focused on hot flashes, finding that hypnotic relaxation therapy lessened them, but “along the way, we discovered there are a lot of secondary benefits, including significantly improved sleep and mood,” said Jim R. Sliwinski, a doctoral student in the department of psychology and neuroscience in Baylor’s College of Arts & Sciences.

Co-researcher Gary Elkins, Ph.D., theorizes that sleep, mood and hot flashes associated with decreased estrogen also have a bearing on memory. Their publication, which reviews previous research by other scholars, proposes a framework for how mind-body interventions may improve memory, which could prove fruitful in doing future research.

“Memory decline may not be solely about decreased estrogen,” said Elkins, director of Baylor’s Mind-Body Medicine Research Laboratory and a professor of psychology and neuroscience.

Peri- and post-menopausal women may find mind-body therapies attractive for many reasons, among them that they do not have the side effects of medications or hormone therapy, said Elkins, author of “Relief from Hot Flashes: The Natural, Drug-Free Program to Reduce Hot Flashes, Improve Sleep and Ease Stress.”

While hormone therapy can increase estrogen, it also is associated with an increased risk of breast cancer and cardiovascular disease for some women, he said.

Researchers have noted that while memory decline can occur with aging in both men and women, women are more likely to report a greater number of memory problems, associating it with estrogen decline. Women also report more concerns about memory than pre-menopausal women do, according to several large-scale survey studies.

A factor that may impact memory is that women are dealing with increased responsibilities, stress or depression over such issues as caring for aging parents. In addition, their concern about memory problems may cause them to be more aware of memory lapses, Sliwinski said.

Even women who can safely be treated with estrogen do not necessarily have improved memory. “It sometimes even is associated with cognition problems,” he said.

Although there are questions about sleep’s specific role in forming and storing memories, researchers generally agree that consolidated sleep throughout a whole night is optimal for learning and memory.

Memory tests and scores over time with study participants — both pre-and post-menopausal — could help shed light on how menopause affects recollection, the Baylor researchers said.

(Image: Shutterstock)

Filed under memory decline menopause memory estrogen cognitive deficit cognitive performance neuroscience science

126 notes

Physical exercise in old age can stimulate brain fitness, but effect decreases with advancing age
Physical exercise in old age can improve brain perfusion as well as certain memory skills. This is the finding of Magdeburg neuroscientists who studied men and women aged between 60 and 77. In younger individuals regular training on a treadmill tended to improve cerebral blood flow and visual memory. However, trial participants who were older than 70 years of age tended to show no benefit of exercise. Thus, the study also indicates that the benefits of exercise may be limited by advancing age. Researchers of the German Center for Neurodegenerative Diseases (DZNE), the University of Magdeburg and the Leibniz Institute for Neurobiology have published these results in the current edition of the journal “Molecular Psychiatry”. Scientists at the Karolinska Institute in Stockholm and the Max Planck Institute for Human Development were also involved in the study.

The 40 test volunteers were healthy for their age, sedentary when the study commenced and divided into two groups. About half of the study participants exercised regularly on a treadmill for 3 months. The other individuals merely performed muscle relaxation sessions. In 7 out of 9 members of the exercise group who were not more than 70 years old, the training improved physical fitness and also tended to increase perfusion in the hippocampus – an area of the brain which is important for memory function. The increased perfusion was accompanied by improved visual memory: at the end of the study, these individuals found it easier to memorize abstract images than at the beginning of the training program. These effects were largely absent in older volunteers who participated in the workout as well as in the members of the control group.
The study included extensive tests of the volunteers’ physical condition and memory. Furthermore, the study participants were examined by magnetic resonance imaging (MRI). This technique enables detailed insights into the interior of the brain.
Exercising against dementia
Physical exercise is known to have considerable health benefits: the effects on the body have been researched extensively, the effects on brain function less so. An increase in brain perfusion through physical exercise had previously only been demonstrated empirically in younger people. The new study shows that some ageing brains also retain this ability to adapt, even though it seems to decrease with advancing age. Furthermore, the results indicate that changes in memory performance resulting from physical exercise are closely linked to changes in brain perfusion.
“Ultimately, we aim to develop measures to purposefully counteract dementia such as Alzheimer’s disease. This is why we want to understand the effects of physical exercise on the brain and the related neurobiological mechanisms. This is essential for developing treatments that are truly effective,” is how Professor Emrah Düzel, site speaker of the DZNE in Magdeburg and director of the Institute of Cognitive Neurology and Dementia Research at the University of Magdeburg, explains the background to the study.
The goal: new brain cells
The researchers’ goal is to cause new nerve cells to grow in the brain. This is how they intend to counter the loss of neurons typical of dementia. “The human brain is able to change and evolve throughout our lives. New nerve cells can form even in adult brains,” says Düzel. “Our aim is to stimulate this so-called neurogenesis. We don’t yet know whether our training methods promote the development of new brain cells. However, fundamental research shows that the formation of new brain cells often goes hand in hand with improved brain perfusion.”
Changes in the hippocampus
Indeed, it did turn out that the treadmill exercise sessions caused more blood to reach the hippocampus in younger participants. “This improves the supply of oxygen and nutrients and may also have other positive effects on the brain’s metabolism,” says the neuroscientist. “However, we have also seen that the effect of the training decreases with age. It is less effective in people aged over 70 than in people in their early 60s. It will be an important goal of our research to understand the causes for this and to find remedies.”
Düzel adds: “It is encouraging to see that visual memory improved as brain perfusion increased. However, effective treatments would also have to affect other brain functions. In our study, the effect was limited to visual short-term memory.”
A combined training for body and mind
Other experiments are now under way in Magdeburg in which test participants are sent on an unusual kind of scavenger hunt: they are assigned the task of finding objects concealed in a computer-generated landscape which is pictured on a large screen. Movement control in this virtual world is done with the help of a treadmill. “This complex situation makes high demands on motor skills and sense of orientation,” explains Düzel. “It challenges both the brain as well as the muscles.”
In the long term, the scientists aim to include people in the early stages of Alzheimer’s disease in their study program. “We are looking for ways of delaying or even stopping the progression of the disease. And we are also researching methods of prevention,” emphasizes Düzel. “Connecting physical activity and mental exercise may have a broad impact, and combined training might become a therapeutic approach. However, this has yet to be shown. In fact, our current results suggest that we may need pharmacological treatments to make exercise more effective.”

Physical exercise in old age can stimulate brain fitness, but effect decreases with advancing age

Physical exercise in old age can improve brain perfusion as well as certain memory skills. This is the finding of Magdeburg neuroscientists who studied men and women aged between 60 and 77. In younger individuals regular training on a treadmill tended to improve cerebral blood flow and visual memory. However, trial participants who were older than 70 years of age tended to show no benefit of exercise. Thus, the study also indicates that the benefits of exercise may be limited by advancing age. Researchers of the German Center for Neurodegenerative Diseases (DZNE), the University of Magdeburg and the Leibniz Institute for Neurobiology have published these results in the current edition of the journal “Molecular Psychiatry”. Scientists at the Karolinska Institute in Stockholm and the Max Planck Institute for Human Development were also involved in the study.

The 40 test volunteers were healthy for their age, sedentary when the study commenced and divided into two groups. About half of the study participants exercised regularly on a treadmill for 3 months. The other individuals merely performed muscle relaxation sessions. In 7 out of 9 members of the exercise group who were not more than 70 years old, the training improved physical fitness and also tended to increase perfusion in the hippocampus – an area of the brain which is important for memory function. The increased perfusion was accompanied by improved visual memory: at the end of the study, these individuals found it easier to memorize abstract images than at the beginning of the training program. These effects were largely absent in older volunteers who participated in the workout as well as in the members of the control group.

The study included extensive tests of the volunteers’ physical condition and memory. Furthermore, the study participants were examined by magnetic resonance imaging (MRI). This technique enables detailed insights into the interior of the brain.

Exercising against dementia

Physical exercise is known to have considerable health benefits: the effects on the body have been researched extensively, the effects on brain function less so. An increase in brain perfusion through physical exercise had previously only been demonstrated empirically in younger people. The new study shows that some ageing brains also retain this ability to adapt, even though it seems to decrease with advancing age. Furthermore, the results indicate that changes in memory performance resulting from physical exercise are closely linked to changes in brain perfusion.

“Ultimately, we aim to develop measures to purposefully counteract dementia such as Alzheimer’s disease. This is why we want to understand the effects of physical exercise on the brain and the related neurobiological mechanisms. This is essential for developing treatments that are truly effective,” is how Professor Emrah Düzel, site speaker of the DZNE in Magdeburg and director of the Institute of Cognitive Neurology and Dementia Research at the University of Magdeburg, explains the background to the study.

The goal: new brain cells

The researchers’ goal is to cause new nerve cells to grow in the brain. This is how they intend to counter the loss of neurons typical of dementia. “The human brain is able to change and evolve throughout our lives. New nerve cells can form even in adult brains,” says Düzel. “Our aim is to stimulate this so-called neurogenesis. We don’t yet know whether our training methods promote the development of new brain cells. However, fundamental research shows that the formation of new brain cells often goes hand in hand with improved brain perfusion.”

Changes in the hippocampus

Indeed, it did turn out that the treadmill exercise sessions caused more blood to reach the hippocampus in younger participants. “This improves the supply of oxygen and nutrients and may also have other positive effects on the brain’s metabolism,” says the neuroscientist. “However, we have also seen that the effect of the training decreases with age. It is less effective in people aged over 70 than in people in their early 60s. It will be an important goal of our research to understand the causes for this and to find remedies.”

Düzel adds: “It is encouraging to see that visual memory improved as brain perfusion increased. However, effective treatments would also have to affect other brain functions. In our study, the effect was limited to visual short-term memory.”

A combined training for body and mind

Other experiments are now under way in Magdeburg in which test participants are sent on an unusual kind of scavenger hunt: they are assigned the task of finding objects concealed in a computer-generated landscape which is pictured on a large screen. Movement control in this virtual world is done with the help of a treadmill. “This complex situation makes high demands on motor skills and sense of orientation,” explains Düzel. “It challenges both the brain as well as the muscles.”

In the long term, the scientists aim to include people in the early stages of Alzheimer’s disease in their study program. “We are looking for ways of delaying or even stopping the progression of the disease. And we are also researching methods of prevention,” emphasizes Düzel. “Connecting physical activity and mental exercise may have a broad impact, and combined training might become a therapeutic approach. However, this has yet to be shown. In fact, our current results suggest that we may need pharmacological treatments to make exercise more effective.”

Filed under physical activity exercise aging dementia memory hippocampus brain cells neuroscience science

228 notes

Mental Rest and Reflection Boost Learning
A new study, which may have implications for approaches to education, finds that brain mechanisms engaged when people allow their minds to rest and reflect on things they’ve learned before may boost later learning.
Scientists have already established that resting the mind, as in daydreaming, helps strengthen memories of events and retention of information. In a new twist, researchers at The University of Texas at Austin have shown that the right kind of mental rest, which strengthens and consolidates memories from recent learning tasks, helps boost future learning.
The results appear online this week in the journal Proceedings of the National Academy of Sciences.
Margaret Schlichting, a graduate student researcher, and Alison Preston, an associate professor of psychology and neuroscience, gave participants in the study two learning tasks in which participants were asked to memorize different series of associated photo pairs. Between the tasks, participants rested and could think about anything they chose, but brain scans found that the ones who used that time to reflect on what they had learned earlier in the day fared better on tests pertaining to what they learned later, especially where small threads of information between the two tasks overlapped. Participants seemed to be making connections that helped them absorb information later on, even if it was only loosely related to something they learned before.
"We’ve shown for the first time that how the brain processes information during rest can improve future learning," says Preston. "We think replaying memories during rest makes those earlier memories stronger, not just impacting the original content, but impacting the memories to come.
Until now, many scientists assumed that prior memories are more likely to interfere with new learning. This new study shows that at least in some situations, the opposite is true.
"Nothing happens in isolation," says Preston. "When you are learning something new, you bring to mind all of the things you know that are related to that new information. In doing so, you embed the new information into your existing knowledge."
Preston described how this new understanding might help teachers design more effective ways of teaching. Imagine a college professor is teaching students about how neurons communicate in the human brain, a process that shares some common features with an electric power grid. The professor might first cue the students to remember things they learned in a high school physics class about how electricity is conducted by wires.
"A professor might first get them thinking about the properties of electricity," says Preston. "Not necessarily in lecture form, but by asking questions to get students to recall what they already know. Then, the professor might begin the lecture on neuronal communication. By prompting them beforehand, the professor might help them reactivate relevant knowledge and make the new material more digestible for them."
This research was conducted with adult participants. The researchers will next study whether a similar dynamic is at work with children.

Mental Rest and Reflection Boost Learning

A new study, which may have implications for approaches to education, finds that brain mechanisms engaged when people allow their minds to rest and reflect on things they’ve learned before may boost later learning.

Scientists have already established that resting the mind, as in daydreaming, helps strengthen memories of events and retention of information. In a new twist, researchers at The University of Texas at Austin have shown that the right kind of mental rest, which strengthens and consolidates memories from recent learning tasks, helps boost future learning.

The results appear online this week in the journal Proceedings of the National Academy of Sciences.

Margaret Schlichting, a graduate student researcher, and Alison Preston, an associate professor of psychology and neuroscience, gave participants in the study two learning tasks in which participants were asked to memorize different series of associated photo pairs. Between the tasks, participants rested and could think about anything they chose, but brain scans found that the ones who used that time to reflect on what they had learned earlier in the day fared better on tests pertaining to what they learned later, especially where small threads of information between the two tasks overlapped. Participants seemed to be making connections that helped them absorb information later on, even if it was only loosely related to something they learned before.

"We’ve shown for the first time that how the brain processes information during rest can improve future learning," says Preston. "We think replaying memories during rest makes those earlier memories stronger, not just impacting the original content, but impacting the memories to come.

Until now, many scientists assumed that prior memories are more likely to interfere with new learning. This new study shows that at least in some situations, the opposite is true.

"Nothing happens in isolation," says Preston. "When you are learning something new, you bring to mind all of the things you know that are related to that new information. In doing so, you embed the new information into your existing knowledge."

Preston described how this new understanding might help teachers design more effective ways of teaching. Imagine a college professor is teaching students about how neurons communicate in the human brain, a process that shares some common features with an electric power grid. The professor might first cue the students to remember things they learned in a high school physics class about how electricity is conducted by wires.

"A professor might first get them thinking about the properties of electricity," says Preston. "Not necessarily in lecture form, but by asking questions to get students to recall what they already know. Then, the professor might begin the lecture on neuronal communication. By prompting them beforehand, the professor might help them reactivate relevant knowledge and make the new material more digestible for them."

This research was conducted with adult participants. The researchers will next study whether a similar dynamic is at work with children.

Filed under learning hippocampus mental rest memory psychology neuroscience science

172 notes

Manipulating memory with light
Just look into the light: not quite, but researchers at the UC Davis Center for Neuroscience and Department of Psychology have used light to erase specific memories in mice, and proved a basic theory of how different parts of the brain work together to retrieve episodic memories.
Optogenetics, pioneered by Karl Diesseroth at Stanford University, is a new technique for manipulating and studying nerve cells using light. The techniques of optogenetics are rapidly becoming the standard method for investigating brain function.
Kazumasa Tanaka, Brian Wiltgen and colleagues at UC Davis applied the technique to test a long-standing idea about memory retrieval. For about 40 years, Wiltgen said, neuroscientists have theorized that retrieving episodic memories — memories about specific places and events — involves coordinated activity between the cerebral cortex and the hippocampus, a small structure deep in the brain.
"The theory is that learning involves processing in the cortex, and the hippocampus reproduces this pattern of activity during retrieval, allowing you to re-experience the event," Wiltgen said. If the hippocampus is damaged, patients can lose decades of memories.
But this model has been difficult to test directly, until the arrival of optogenetics.
Wiltgen and Tanaka used mice genetically modified so that when nerve cells are activated, they both fluoresce green and express a protein that allows the cells to be switched off by light. They were therefore able both to follow exactly which nerve cells in the cortex and hippocampus were activated in learning and memory retrieval, and switch them off with light directed through a fiber-optic cable.
They trained the mice by placing them in a cage where they got a mild electric shock. Normally, mice placed in a new environment will nose around and explore. But when placed in a cage where they have previously received a shock, they freeze in place in a “fear response.”
Tanaka and Wiltgen first showed that they could label the cells involved in learning and demonstrate that they were reactivated during memory recall. Then they were able to switch off the specific nerve cells in the hippocampus, and show that the mice lost their memories of the unpleasant event. They were also able to show that turning off other cells in the hippocampus did not affect retrieval of that memory, and to follow fibers from the hippocampus to specific cells in the cortex.
"The cortex can’t do it alone, it needs input from the hippocampus," Wiltgen said. "This has been a fundamental assumption in our field for a long time and Kazu’s data provides the first direct evidence that it is true."
They could also see how the specific cells in the cortex were connected to the amygdala, a structure in the brain that is involved in emotion and in generating the freezing response.

Manipulating memory with light

Just look into the light: not quite, but researchers at the UC Davis Center for Neuroscience and Department of Psychology have used light to erase specific memories in mice, and proved a basic theory of how different parts of the brain work together to retrieve episodic memories.

Optogenetics, pioneered by Karl Diesseroth at Stanford University, is a new technique for manipulating and studying nerve cells using light. The techniques of optogenetics are rapidly becoming the standard method for investigating brain function.

Kazumasa Tanaka, Brian Wiltgen and colleagues at UC Davis applied the technique to test a long-standing idea about memory retrieval. For about 40 years, Wiltgen said, neuroscientists have theorized that retrieving episodic memories — memories about specific places and events — involves coordinated activity between the cerebral cortex and the hippocampus, a small structure deep in the brain.

"The theory is that learning involves processing in the cortex, and the hippocampus reproduces this pattern of activity during retrieval, allowing you to re-experience the event," Wiltgen said. If the hippocampus is damaged, patients can lose decades of memories.

But this model has been difficult to test directly, until the arrival of optogenetics.

Wiltgen and Tanaka used mice genetically modified so that when nerve cells are activated, they both fluoresce green and express a protein that allows the cells to be switched off by light. They were therefore able both to follow exactly which nerve cells in the cortex and hippocampus were activated in learning and memory retrieval, and switch them off with light directed through a fiber-optic cable.

They trained the mice by placing them in a cage where they got a mild electric shock. Normally, mice placed in a new environment will nose around and explore. But when placed in a cage where they have previously received a shock, they freeze in place in a “fear response.”

Tanaka and Wiltgen first showed that they could label the cells involved in learning and demonstrate that they were reactivated during memory recall. Then they were able to switch off the specific nerve cells in the hippocampus, and show that the mice lost their memories of the unpleasant event. They were also able to show that turning off other cells in the hippocampus did not affect retrieval of that memory, and to follow fibers from the hippocampus to specific cells in the cortex.

"The cortex can’t do it alone, it needs input from the hippocampus," Wiltgen said. "This has been a fundamental assumption in our field for a long time and Kazu’s data provides the first direct evidence that it is true."

They could also see how the specific cells in the cortex were connected to the amygdala, a structure in the brain that is involved in emotion and in generating the freezing response.

Filed under optogenetics memory hippocampus cerebral cortex nerve cells neuroscience science

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Sugar Linked to Memory Problems in Adolescent Rats

Studying rats as model subjects, scientists found that adolescents were at an increased risk of suffering negative health effects from sugar-sweetened beverage consumption.

Adolescent rats that freely consumed large quantities of liquid solutions containing sugar or high-fructose corn syrup (HFCS) in concentrations comparable to popular sugar-sweetened beverages experienced memory problems and brain inflammation, and became pre-diabetic, according to a new study from USC. Neither adult rats fed the sugary drinks nor adolescent rats who did not consume sugar had the same issues.

“The brain is especially vulnerable to dietary influences during critical periods of development, like adolescence,” said Scott Kanoski, corresponding author of the study and an assistant professor at the USC Dornsife College of Letters, Arts and Sciences.

Kanoski collaborated with USC’s Ted Hsu, Vaibhav Konanur, Lilly Taing, Ryan Usui, Brandon Kayser, and Michael Goran. Their study, which tested a total of 76 rats, was published online by the journal Hippocampus on Sept. 23.

About 35 to 40 percent of the rats’ caloric intake was from sugar or HFCS. For comparason, added sugars make up about 17 percent of the total caloric intake of teens in the U.S. on average, according to the CDC.

The rats were then tested in mazes that probe their spatial memory ability. Adolescent rats that had consumed the sugary beverages, particularly HFCS, performed worse on the test than any other group – which may be the result of the neuroinflammation detected in the hippocampus, Kanoski said.

The hippocampus is a part of the temporal lobe located deep within the brain that controls memory formation. People with Alzheimer’s Disease and other dementias often suffer damage to the hippocampus.

“Consuming a diet high in added sugars not only can lead to weight gain and metabolic disturbances, but can also negatively impact our neural functioning and cognitive ability.” Kanoski said. Next, Kanoski and his team plant to see how different monosaccharides (simple sugars) and HFCS affect the brain.

(Source: pressroom.usc.edu)

Filed under hippocampus memory sugar cognitive function adolescence neuroscience science

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(Image caption: 3D image of the hippocampus of a rat. Credit: M. Pyka)
A glimpse into the 3D brain
People who wish to know how memory works are forced to take a glimpse into the brain. They can now do so without bloodshed: RUB researchers have developed a new method for creating 3D models of memory-relevant brain structures. They published their results in the trade journal “Frontiers in Neuroanatomy”.
Sea Horse gave the hippocampus the name
The way neurons are interconnected in the brain is very complicated. This holds especially true for the cells of the hippocampus. It is one of the oldest brain regions and its form resembles a sea horse (hippocampus in Latin). The hippocampus enables us to navigate space securely and to form personal memories. So far, the anatomic knowledge of the networks inside the hippocampus and its connection to the rest of the brain has left scientists guessing which information arrived where and when.
Signals spread through the brain
Accordingly, Dr Martin Pyka and his colleagues from the Mercator Research Group have developed a method which facilitates the reconstruction of the brain’s anatomic data as a 3D model on the computer. This approach is quite unique, because it enables automatic calculation of the neural interconnection on the basis of their position inside the space and their projection directions. Biologically feasible network structures can thus be generated more easily than it used to be the case with the method available to date. Deploying 3D models, the researchers use this technique to monitor the way neural signals spread throughout the network time-wise. They have, for example, found evidence that the hippocampus’ form and size could explain why neurons in those networks fire in certain frequencies.
Information become memories
In future, this method may help us understand how animals, for example, combine various information to form memories within the hippocampus, in order to memorise food sources or dangers and to remember them in certain situations.

(Image caption: 3D image of the hippocampus of a rat. Credit: M. Pyka)

A glimpse into the 3D brain

People who wish to know how memory works are forced to take a glimpse into the brain. They can now do so without bloodshed: RUB researchers have developed a new method for creating 3D models of memory-relevant brain structures. They published their results in the trade journal “Frontiers in Neuroanatomy”.

Sea Horse gave the hippocampus the name

The way neurons are interconnected in the brain is very complicated. This holds especially true for the cells of the hippocampus. It is one of the oldest brain regions and its form resembles a sea horse (hippocampus in Latin). The hippocampus enables us to navigate space securely and to form personal memories. So far, the anatomic knowledge of the networks inside the hippocampus and its connection to the rest of the brain has left scientists guessing which information arrived where and when.

Signals spread through the brain

Accordingly, Dr Martin Pyka and his colleagues from the Mercator Research Group have developed a method which facilitates the reconstruction of the brain’s anatomic data as a 3D model on the computer. This approach is quite unique, because it enables automatic calculation of the neural interconnection on the basis of their position inside the space and their projection directions. Biologically feasible network structures can thus be generated more easily than it used to be the case with the method available to date. Deploying 3D models, the researchers use this technique to monitor the way neural signals spread throughout the network time-wise. They have, for example, found evidence that the hippocampus’ form and size could explain why neurons in those networks fire in certain frequencies.

Information become memories

In future, this method may help us understand how animals, for example, combine various information to form memories within the hippocampus, in order to memorise food sources or dangers and to remember them in certain situations.

Filed under 3d model hippocampus memory neurons brain structure neuroscience science

394 notes

How curiosity changes the brain to enhance learning
The more curious we are about a topic, the easier it is to learn information about that topic. New research publishing online October 2 in the Cell Press journal Neuron provides insights into what happens in our brains when curiosity is piqued. The findings could help scientists find ways to enhance overall learning and memory in both healthy individuals and those with neurological conditions.
"Our findings potentially have far-reaching implications for the public because they reveal insights into how a form of intrinsic motivation—curiosity—affects memory. These findings suggest ways to enhance learning in the classroom and other settings," says lead author Dr. Matthias Gruber, of University of California at Davis.
For the study, participants rated their curiosity to learn the answers to a series of trivia questions. When they were later presented with a selected trivia question, there was a 14 second delay before the answer was provided, during which time the participants were shown a picture of a neutral, unrelated face. Afterwards, participants performed a surprise recognition memory test for the faces that were presented, followed by a memory test for the answers to the trivia questions. During certain parts of the study, participants had their brains scanned via functional magnetic resonance imaging.
The study revealed three major findings. First, as expected, when people were highly curious to find out the answer to a question, they were better at learning that information. More surprising, however, was that once their curiosity was aroused, they showed better learning of entirely unrelated information (face recognition) that they encountered but were not necessarily curious about. People were also better able to retain the information learned during a curious state across a 24-hour delay. “Curiosity may put the brain in a state that allows it to learn and retain any kind of information, like a vortex that sucks in what you are motivated to learn, and also everything around it,” explains Dr. Gruber.
Second, the investigators found that when curiosity is stimulated, there is increased activity in the brain circuit related to reward. “We showed that intrinsic motivation actually recruits the very same brain areas that are heavily involved in tangible, extrinsic motivation,” says Dr. Gruber. This reward circuit relies on dopamine, a chemical messenger that relays messages between neurons.
Third, the team discovered that when curiosity motivated learning, there was increased activity in the hippocampus, a brain region that is important for forming new memories, as well as increased interactions between the hippocampus and the reward circuit. “So curiosity recruits the reward system, and interactions between the reward system and the hippocampus seem to put the brain in a state in which you are more likely to learn and retain information, even if that information is not of particular interest or importance,” explains principal investigator Dr. Charan Ranganath, also of UC Davis.
The findings could have implications for medicine and beyond. For example, the brain circuits that rely on dopamine tend to decline in function as people get older, or sooner in people with neurological conditions. Understanding the relationship between motivation and memory could therefore stimulate new efforts to improve memory in the healthy elderly and to develop new approaches for treating patients with disorders that affect memory. And in the classroom or workplace, learning what might be considered boring material could be enhanced if teachers or managers are able to harness the power of students’ and workers’ curiosity about something they are naturally motivated to learn.

How curiosity changes the brain to enhance learning

The more curious we are about a topic, the easier it is to learn information about that topic. New research publishing online October 2 in the Cell Press journal Neuron provides insights into what happens in our brains when curiosity is piqued. The findings could help scientists find ways to enhance overall learning and memory in both healthy individuals and those with neurological conditions.

"Our findings potentially have far-reaching implications for the public because they reveal insights into how a form of intrinsic motivation—curiosity—affects memory. These findings suggest ways to enhance learning in the classroom and other settings," says lead author Dr. Matthias Gruber, of University of California at Davis.

For the study, participants rated their curiosity to learn the answers to a series of trivia questions. When they were later presented with a selected trivia question, there was a 14 second delay before the answer was provided, during which time the participants were shown a picture of a neutral, unrelated face. Afterwards, participants performed a surprise recognition memory test for the faces that were presented, followed by a memory test for the answers to the trivia questions. During certain parts of the study, participants had their brains scanned via functional magnetic resonance imaging.

The study revealed three major findings. First, as expected, when people were highly curious to find out the answer to a question, they were better at learning that information. More surprising, however, was that once their curiosity was aroused, they showed better learning of entirely unrelated information (face recognition) that they encountered but were not necessarily curious about. People were also better able to retain the information learned during a curious state across a 24-hour delay. “Curiosity may put the brain in a state that allows it to learn and retain any kind of information, like a vortex that sucks in what you are motivated to learn, and also everything around it,” explains Dr. Gruber.

Second, the investigators found that when curiosity is stimulated, there is increased activity in the brain circuit related to reward. “We showed that intrinsic motivation actually recruits the very same brain areas that are heavily involved in tangible, extrinsic motivation,” says Dr. Gruber. This reward circuit relies on dopamine, a chemical messenger that relays messages between neurons.

Third, the team discovered that when curiosity motivated learning, there was increased activity in the hippocampus, a brain region that is important for forming new memories, as well as increased interactions between the hippocampus and the reward circuit. “So curiosity recruits the reward system, and interactions between the reward system and the hippocampus seem to put the brain in a state in which you are more likely to learn and retain information, even if that information is not of particular interest or importance,” explains principal investigator Dr. Charan Ranganath, also of UC Davis.

The findings could have implications for medicine and beyond. For example, the brain circuits that rely on dopamine tend to decline in function as people get older, or sooner in people with neurological conditions. Understanding the relationship between motivation and memory could therefore stimulate new efforts to improve memory in the healthy elderly and to develop new approaches for treating patients with disorders that affect memory. And in the classroom or workplace, learning what might be considered boring material could be enhanced if teachers or managers are able to harness the power of students’ and workers’ curiosity about something they are naturally motivated to learn.

Filed under curiosity hippocampus memory learning nucleus accumbens midbrain neuroscience science

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