Neuroscience  

Neuroscientists have used a complex digital brain simulation of a rat brain that combines functional connectivity analysis and network modeling to investigate synaptic mechanisms of memory formation and pattern completion in hippocampal CA3 network.

Neuroscientists have used advanced brain simulations to unravel the complex synaptic mechanisms of pattern completion in hippocampus of the brain. The researchers' findings suggest that the rules of synaptic connectivity between CA3 pyramidal cells in the hippocampus contribute to the remarkable efficiency of pattern completion.

The hippocampal CA3 region is known to play a key role in learning and memory. One of the most remarkable properties of the network is its ability to retrieve previously stored memories from incomplete or degraded versions, a phenomenon that is widely known as pattern completion.

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It is widely accepted that the synapses between CA3 pyramidal cells, the recurrent CA3–CA3 synapses, play a key role in pattern completion, but how this exactly works is still a mystery.

"The results provide a nice demonstration of how the Hopfield quote “build it, and you understand it” can be successfully applied to important questions in neuroscience."

Now, in  recent research published in the journal Science, neuroscientists Jose Guzman, Alois Schlögl, Michael Frotscher, and Peter Jonas have investigated these mechanisms by combining functional connectivity analysis and network modeling. Their findings suggest that the rules of synaptic connectivity between CA3 pyramidal cells contribute to the remarkable efficiency of pattern completion.

Previous theories of the hippocampal formation often depicted the region as a network of highly interconnected cells. The neuroscientists from the Institute of Science and Technology Austria (IST Austria) tested this hypothesis using a technique that allows monitoring the connection between electrical signals in up to eight neurons at the same time.

They made several highly surprising observations. First, they found that connectivity was sparse, with an average connection probability of approximately 1%. This massively challenges the dogma of a network of highly connected cells. Even more surprisingly, they discovered that connectivity in the network is not random, but exhibits connectivity motifs that occur much more frequently than expected for a random network. The structure of the hippocampal CA3 network may be somewhat reminiscent of a “small world” architecture as found in social networks. Finally, the authors revealed that synaptic connections between two cells are mediated by only one or two synaptic contacts. This is also remarkable because much higher numbers have been found for excitatory synaptic connections in the neocortex.

What did these 'rules' man for memory formation? To address this question, Jonas,who leads the cellular neuroscience group and his team built a model of the CA3 network that incorporates many of these new experimental observations. In contrast to many previous studies, the network was implemented in full size, so that all 330,000 CA3 neurons of the rat hippocampus were simulated.

They found that a full-size network model with realistic connectivity of 1% was indeed able to perform the network computation of pattern completion. Also, they discovered that the presence of connectivity motives increased, under certain conditions, the performance of the network. Finally, the design of synaptic connections based on one or two synaptic contacts also seems useful for pattern completion, apparently because it minimizes redundancy in the flow of information in the network.

For the researchers, both macro- and microconnectivity facilitate pattern completion in the CA3 cell network. “The results provide a nice demonstration of how the Hopfield quote “build it, and you understand it” can be successfully applied to important questions in neuroscience,” states Jonas.

SOURCE  IST Austria

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Artificial Intelligence  

Jeff Hawkins and his team at Numenta have developed a theory of how the brain learns and understands sequences of patterns that may be an essential component for creating intelligent machines.

Researchers at Numenta Inc. have published a new theory that represents a breakthrough in understanding how networks of neurons in the neocortex learn sequences. A paper, authored by Numenta co-founder Jeff Hawkins and VP of Research Subutai Ahmad, “Why Neurons Have Thousands of Synapses, A Theory of Sequence Memory in Neocortex,” has been published in the Frontiers in Neural Circuits Journal, a publication devoted to research in neural circuits, serving the worldwide neuroscience community.

"This study is a key milestone on the path to achieving that long-sought goal of creating truly intelligent machines that simulate human cerebral cortex and forebrain system operations."

“This study is a key milestone on the path to achieving that long-sought goal of creating truly intelligent machines that simulate human cerebral cortex and forebrain system operations,” commented Michael Merzenich, PhD, Professor Emeritus UCSF,Chief Scientific Officer for Posit Science.

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The Numenta paper introduces two advances 

First, it provides an explanation of why neurons in the neocortex have thousands of synapses, and why the synapses are segregated onto different parts of the cell, called dendrites. The authors propose that the majority of these synapses are used to learn transitions of patterns, a feature missing from most artificial neural networks.

Second, the authors show that neurons with these properties, arranged in layers and columns - a structure observed throughout the neocortex - form a powerful sequence memory. This suggests the new sequence memory algorithm could be a unifying principle for understanding how the neocortex works. Through simulations, the authors show the new sequence memory exhibits a number of important properties such as the ability to learn complex sequences, continuous unsupervised learning, and extremely high fault tolerance.

Implications for Artificial Intelligence and Neuroscience

“Our paper makes contributions in both neuroscience and machine learning,” Hawkins noted. “From a neuroscience perspective, it offers a computational model of pyramidal neurons, explaining how a neuron can effectively use thousands of synapses and computationally active dendrites to learn sequences. From a machine learning and computer science perspective, it introduces a new sequence memory algorithm that we believe will be important in building intelligent machines.”

“This research extends the work Jeff first outlined in his 2004 book On Intelligence and encompasses many years of research we have undertaken here at Numenta,” said Ahmad, “It explains the neuroscience behind our HTM (Hierarchical Temporal Memory) technology and makes several detailed predictions that can be experimentally verified. The software we have created proves that the theory actually works in real world applications.”

Numenta’s primary goal is to reverse engineer the neocortex, to understand the detailed biology underlying intelligence. The Numenta team also believes this is the quickest route to creating machine intelligence. As a result of this approach, the neuron and network models described in the new paper are strikingly different than the neuron and network models being used in today’s deep learning and other artificial neural networks. Functionally, the new theory addresses several of the biggest challenges confronting deep learning today, such as the lack of continuous and unsupervised learning.

SOURCE  Business Wire

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Data Storage  

A major step in the development of digital data storage that is capable of surviving for billions of years has been made. Using nanostructured glass, scientists have developed the recording and retrieval processes of five dimensional (5D) digital data by femtosecond laser writing.

Researchers at the University of Southampton have made a development in the field of of digital data storage that may be capable of surviving for billions of years.

Using nanostructured glass, scientists from the University’s Optoelectronics Research Centre (ORC) have developed the recording and retrieval processes of five dimensional (5D) digital data by femtosecond laser writing.

"It is thrilling to think that we have created the technology to preserve documents and information and store it in space for future generations."

The storage solution allows unprecedented properties including 360 TB/disc data capacity, thermal stability up to 1,000°C and virtually unlimited lifetime at room temperature (13.8 billion years at 190°C ) opening a new era of eternal data archiving.

The technology could be highly useful for organisations with big archives, such as national archives, museums and libraries, to preserve their information and records and could also be used for very stable and safe form of portable memory.

The technology was first experimentally demonstrated in 2013 when a 300 kb digital copy of a text file was successfully recorded in 5D. Now the researchers have further developed their 'Superman’ memory crystal.'

Now, major documents from human history such as Universal Declaration of Human Rights (UDHR), Newton’s Opticks, Magna Carta and Kings James Bible, have been saved as digital copies that could survive the human race. A copy of the UDHR encoded to 5D data storage was recently presented to UNESCO by the ORC at the International Year of Light (IYL) closing ceremony in Mexico.

Universal Declaration of Human Rights recorded into 5D optical data

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The documents were recorded using ultrafast laser, producing extremely short and intense pulses of light. The file is written in three layers of nanostructured dots separated by five micrometres (one millionth of a metre). The self-assembled nanostructures change the way light travels through glass, modifying polarisation of light that can then be read by combination of optical microscope and a polariser, similar to that found in Polaroid sunglasses.

Coined as the ‘Superman memory crystal’, as the glass memory has been compared to the “memory crystals” used in the Superman films, the data is recorded via self-assembled nanostructures created in fused quartz. The information encoding is realised in five dimensions: the size and orientation in addition to the three dimensional position of these nanostructures.

Professor Peter Kazansky, from the ORC, says: “It is thrilling to think that we have created the technology to preserve documents and information and store it in space for future generations. This technology can secure the last evidence of our civilisation: all we’ve learnt will not be forgotten.”

The researchers will present their research at the photonics industry's renowned SPIE Photonics West—The International Society for Optical Engineering Conference in San Francisco, USA this week. The invited paper, ‘5D Data Storage by Ultrafast Laser Writing in Glass’ will be presented by the team.

SOURCE  University of Southampton

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Memory Implants  

A memory prosthesis being trialed next year could not only repair loss of long-term memory but could potentially be used as a model of how to upload new skills and memories directly into our brains.

A new human memory prosthesis will be tested next year could not only restore long-term recall but may eventually be used to upload new skills and memories directly to the brain according to researcher Theodore (Ted) Berger.

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The first trials will be undertaken on patients with epilepsy. Seizures can sometimes damage the hippocampus, causing the brain to be unable to form long-term memories.

To repair this functionality, Berger, a biomedical engineer and a developer of neuro-prosthesis technology models, will use brain implants to try to replace damaged or dysfunctional nerve tissue. His colleagues at the University of Southern California have already used electrodes implanted in people’s brains as part of epilepsy treatment to record electrical activity associated with memory.

The team has also developed an algorithm that could predict the neural activity thought to occur when a short-term memory becomes a long-term memory, as it passes through the hippocampus.

"There is good reason to believe that the sharing of memory can happen."

Next year, Berger’s team will use this algorithm to communicate between the electrodes and the subjects' brains to help predict and then mimic the activity that should occur during long-term memories formation.

“Hopefully, it will repair their long-term memory,” says Berger. Previous studies using animals suggest that the prosthesis might even give people a better memory than they could expect naturally.

A similar approach could eventually be used to implant new memories into the brain. “There is good reason to believe that the sharing of memory can happen,” says Berger.

DARPA is also seeking to accelerate the development of memory implant technology.

Berger’s team recorded brain activity in a rat that had been trained to perform a specific task. The memory implant then replicated that activity in a rat that hadn’t been trained. The second rat was able to learn the task much faster than the first rat – as if it already had some memory of the task.

Are you thinking what we are?

SOURCE  New Scientist

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 Cryonics  

Researchers have now proven that cryogenically-suspended worms maintain their memories after reanimation.

S ome animals can survive extended periods of actually being frozen.  Understanding and controlling this ability is a key area of researcher for the field of cryonics—in the hope that someday frozen humans who were about to die of disease or accident can be revived and restored.

Animals undergo the process by somehow regulating the way their bodies enter a frozen state, and at the other end of the cycle, controlling the thawing out process.

Until recently it hasn’t been understood whether important higher-level functions, like memory, are preserved in the natural cryonic process. Now, Natasha Vita-More and Daniel Barranco, have proven for the first time that cryogenically-suspended nematode worms keep their memories after reanimation.

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The researchers first trained the C. Ekegans worms to move to specific areas in an area when they smelled benzaldehyde (a component of almond oil). After learingn this task, the worms were bathed in a glycerol-based cryoprotectant solution and put into to a cryogenic state.

"This is the first evidence of preservation of memory after cryopreservation vitrification or slow freezing."

When the worms were reanimated, they were able to remember the lesson and moved to the correct position in their training area when benzaldehyde was provided.

Two different methods of freezing were tested on the worms: the first effort was based on the traditional way to freeze cells or organs in a low concentration of cryoprotectant and then slowly cool and reanimate the creatures. The second method  involved a more aggressive procedure known as vitrification.

Vitrification uses a higher concentration of cryoprotectant, but does the freezing and thawing rapidly so that ice crystals which can damage cell structures, do not form as readily. Only about a third of the worms that were frozen by the slow method actually survived reanimation, while almost all of those vitrified will survive.

Vita-More and Barranco did find though that worms frozen by either method retained the tested memory functions. They concluded:

Our results show that the mechanisms that regulate odorant imprinting (a form of long-term memory) in young C. elegans have not been modified by either the process of vitrification or by slow freezing in the adult stage. This is the first evidence of preservation of memory after cryopreservation vitrification or slow freezing).

The research is an important step for the study of cryonics, and is an indication that the process currently being undertaken at facilities like Alcor's may one day bear fruit for the people frozen within.

Demonstrating that worm brains can handle top-down freezing by artificial means is an important step towards doing the same for larger organisms, like humans. Additional research may make survivable cryonic suspension a real solution for the current problem of aging and disease.


SOURCE  Extreme Tech

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 Neuroscience  

Researchers have found that the signalling protein Asef2 is a critical regulator of dendritic spines and synapses and memory formation. Asef2 has been found to promote spine and synapse formation by activating another protein called Rac. They also discovered that yet another protein, spinophilin, recruits Asef2 and guides it to specific spines.

Every time you make a memory, somewhere in your brain a tiny filament reaches out from one neuron and forms an electrochemical connection to a neighboring neuron.

Now, a team of biologists at Vanderbilt University, headed by Associate Professor of Biological Sciences Donna Webb, have studied how these connections are formed at the molecular and cellular level.

"Once we figure out the mechanisms involved, then we may be able to find drugs that can restore spine formation in people who have lost it, which could give them back their ability to remember."

The filaments that make these new connections are called dendritic spines and, in a series of experiments published in the Journal of Biological Chemistry, the researchers report that a specific signaling protein, Asef2, a member of a family of proteins that regulate cell migration and adhesion, plays a critical role in spine formation. This is significant because Asef2 has been linked to autism and the co-occurrence of alcohol dependency and depression.

“Alterations in dendritic spines are associated with many neurological and developmental disorders, such as autism, Alzheimer’s disease and Down Syndrome,” said Webb. “However, the formation and maintenance of spines is a very complex process that we are just beginning to understand.”

Fluorescent microphotograph of neurons that shows filapodia extending out from dendrite. Image Source: Webb Lab / Vanderbilt)

Neuron cell bodies produce two kinds of long fibers that weave through the brain: dendrites and axons. Axons transmit electrochemical signals from the cell body of one neuron to the dendrites of another neuron. Dendrites receive the incoming signals and carry them to the cell body. This is the way that neurons communicate with each other.

As they wait for incoming signals, dendrites continually produce tiny flexible filaments called filopodia. These poke out from the surface of the dendrite and wave about in the region between the cells searching for axons. At the same time, biologists think that the axons secrete chemicals of an unknown nature that attract the filopodia. When one of the dendritic filaments makes contact with one of the axons, it begins to adhere and to develop into a spine. The axon and spine form the two halves of a synaptic junction. New connections like this form the basis for memory formation and storage.

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Autism has been associated with immature spines, which do not connect properly with axons to form new synaptic junctions. However, a reduction in spines is characteristic of the early stages of Alzheimer’s disease. This may help explain why individuals with Alzheimer’s have trouble forming new memories.

The formation of spines is driven by actin, a protein that produces microfilaments and is part of the cytoskeleton. Webb and her colleagues showed that Asef2 promotes spine and synapse formation by activating another protein called Rac, which is known to regulate actin activity. They also discovered that yet another protein, spinophilin, recruits Asef2 and guides it to specific spines.

“Once we figure out the mechanisms involved, then we may be able to find drugs that can restore spine formation in people who have lost it, which could give them back their ability to remember,” said Webb.


SOURCE  Vanderbilt University

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 Self Improvement  

There are many scientifically proven ways to improve your memory. Here a few hacks that can help you take your memory to the next level.

F

orgetfulness is usually a normal part of life, especially if you're getting older. The good news is that there are lots of scientifically proven ways to improve your memory and make remembering things come more easily. Take a look at the following tricky hacks to help you improve your memory day by day:

Do Crosswords and Play Brain Games

Using your brain for fun activities like crosswords and teasers can have a beneficial effect on your memory. Marcel Danesi, PhD, researcher and author of Extreme Brain Workout, theorizes that these types of activities keep synapses in the brain active, including those that are used to form new memories and recall information. Playing these kinds of games during your leisure time is an easy way to help give your brain a workout and your memory a boost, with only putting in a little time.

Want a challenge?  Try a map from Mike Bostock's algorithm

Use Your Words

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By saying things out loud, you help commit them to memory, according to Cynthia Green, Ph.D., president of Memory Arts LLC. So when you meet someone new, repeat their name throughout the conversation. If you're trying to remember where you parked, say the name of the streets or a landmark out loud. This simple exercise will help you commit things to memory early on, which is especially helpful if you are bad with names.

Eat Nutritiously

You've probably heard that fish is brain food—that's because it's chock full of omega-3 fatty acids. Nuts and avocado are also great sources of these brain boosting antioxidants. Gary Small, MD, director of the UCLA Memory Clinic, fruits and vegetables, especially berries, are also great for your memory. A study conducted by the University of Reading also touted the benefits of berries for improving recall. With the proper fuel, your mind and memory will feel much sharper throughout the day.

Invoke Your Senses

According to John M. Grohol, Psy.D., founder and CEO of Psych Central, using your senses when you're trying to remember something makes it easier to recall. For example, try chewing a certain type of gum when you're studying for a test, and the same gum when you actually take the test. To boost the sensory recall, wear the same perfume or a soft scarf.

Get on Your Feet

Research shows that regular exercise improves memory and prevents age related cognitive decline. Exercise enlarges the hippocampus, which is part of the brain responsible for memory recall. Regular exercise has countless benefits for both brain and body, so if your memory needs a little help, consider amping up your workout routine.

Really want to enlarge your hippocampus? Build yourself this hamster wheel standing desk.

By trying these five hacks, you may find that it's much easier for you to remember names, passwords, parking spaces, and all the other facts that seem like they slip through your fingers when you need them most.

SOURCE  The information for this article was provided by professionals who offer a bachelor degree in psychology for students who are interested in human behavior and brain function.

By Dixie Somers

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Author Bio - Dixie is a freelance writer who loves to write about business, finance and self improvemet. She lives in Arizona with her husband and three beautiful daughters.

 Neuroscience  

Scientists have implanted new memories into mice while they slept.  They hope this technique can be developed to alter problematic memories in people. The idea is to attach good thoughts to bad memories, such as those that linger after traumatic experiences.

M

ice can recall artificial memories created during sleep once they’re awake, researchers from the French National Center for Scientific Research (CNRS) and their colleagues have reported in Nature Neuroscience. The findings support a causal role between the firing of specialized neurons called place cells and the ability of these neurons to represent a particular location in space.

Place cells, part of the brain’s “inner GPS,” were first discovered by John O’Keefe, are a type of pyramidal neuron within the hippocampus that become active when an animal enters a particular place in an environment.

"The animal developed a goal-directed strategy for the [location], as if the animal had a conscious recollection that there was a reward there."

Karim Benchenane, a neuroscience researcher at CNRS and ESPCI-ParisTech and his colleagues first identified a single place cell in the hippocampus of each mouse that fired when the animal was in a specific location and measured the average time each mouse spent in that location prior to any manipulation.

Then, when that particular place cell became spontaneously active during either an awake or sleep state, an automatic stimulation of the medial forebrain bundle—a part of the brain associated with positive reward sensations—was executed through a brain-computer interface. This stimulation has long been known to result in the release of dopamine neurotransmitters, similar to what happens when the mouse receives a food or some other reward. Each mouse received the stimulation either during an awake or sleeping state, but not both.

a. Wake pairing protocol. The paradigm consisted in four sessions: 1) free exploration and place field identification, 2) basal exploration (PRE), 3) 15 minutes exploration with pairing where online detected spikes of a given place cell triggered MFB stimulation, and 4) test exploration (POST). In PRE and POST session a minimum of eight 60s—trials with changing starting point (gray circles) is performed. Analyses were carried on the first 4 trials where animal was actively exploring. b. Sleep pairing protocol. As in panel a, the sleep protocol is composed of the same four sessions except that spike—stimulation pairing is performed during 1h of sleep. This protocol was always followed by free exploration to erase the learning (extinction exploration) and a control wake pairing. c. Classical Place preference task. Mouse position was tracked in real time with a video camera during a session lasting 15 minutes. Rewarding stimulations were then delivered when mice reached a pre—established area, covering around 5% of the total surface of exploration. This stimulation phase was preceded by a basal exploration (PRE) and followed by a probe exploration (POST) as described in panel a. d. Method for the choice of the 4 starting points used in PRE and POST sessions of all place preference paradigms. Image Benchenane et al./Nature Neuroscience

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The linkage of a specific place cell with rewarding stimulation resulted in the animals spending about five times more time in the area associated with the place cell activity compared to the time they spent in that location prior to the stimulation experiment.

When this link between the place cell and reward trigger occurred during sleep in a second set of mice, the animals were more likely to go directly to the location associated with that place cell upon waking.

“The animal developed a goal-directed strategy for the [location], as if the animal had a conscious recollection that there was a reward there,” explained Benchenane.

In awake animals, the activity of place cells has been associated with being in a specific location, but so far, it has been difficult to directly attribute place cell activity to a representation of that physical location by the animal’s brain. Focusing on the animal’s place cell activity during sleep, when only replay is active, Benchenane and his colleagues were able to directly link place cell firing to spatial navigation.

Benchenane doesn't think the technique used in this study can be used to implant many other types of memories, like skills—at least for the time being. Spatial memories are easier to modify because they are among the best understood, and tied to specific neurons.

He hopes his technique can be developed to alter problematic memories in people. The idea is to attach good thoughts to bad memories, such as those that linger after traumatic experiences. "If you can identify where in the brain a person is reactivating a phobia-associated experience, you might be able to create a positive association," he says.


SOURCE  The Scientist

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 Aging  

People aged 80 and above, but with memories that are as sharp as those of healthy persons decades younger—SuperAgers—have distinctly different brains than those of normal people, according to new imaging and analysis.

SuperAgers, aged 80 and above, have distinctly different looking brains than those of normal older people, according to new research. The work is the initial stages of revealing why the memories of these cognitively older individuals don’t seem to suffer the usual effects of aging.

SuperAgers have memories that are as sharp as those of healthy persons decades younger.

Understanding their unique “brain signature” will enable scientists to decipher the genetic or molecular source and may foster the development of strategies to protect the memories of normal aging persons as well as treat dementia.

Published in the Journal of Neuroscience, the study is the first to quantify brain differences of SuperAgers and normal older people.

Cognitive SuperAgers were first identified in 2007 by scientists at Northwestern University’s Cognitive Neurology and Alzheimer’s Disease Center at Northwestern University Feinberg School of Medicine.

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Their typical brain signature has three common components when compared with normal persons of similar ages: a thicker region of the cortex; significantly fewer tangles (a primary marker of Alzheimer’s disease) and a whopping supply of spindle neurons, also called, von Economo neurons (VENs), which have been linked to higher social intelligence.

VEN cells are also present in such species as whales, elephants, dolphins and higher apes.

“The brains of the SuperAgers are either wired differently or have structural differences when compared to normal individuals of the same age,” said Changiz Geula, study senior author and a research professor at the Cognitive Neurology and Alzheimer’s Disease Center. “It may be one factor, such as expression of a specific gene, or a combination of factors that offers protection.”

“Identifying the factors that contribute to the SuperAgers’ unusual memory capacity may allow us to offer strategies to help the growing population of ‘normal’ elderly maintain their cognitive function and guide future therapies to treat certain dementias,” said Tamar Gefen, the first study author and a clinical neuropsychology doctoral candidate at Feinberg.

"Identifying the factors that contribute to the SuperAgers’ unusual memory capacity may allow us to offer strategies to help the growing population of ‘normal’ elderly maintain their cognitive function and guide future therapies to treat certain dementias."

MRI imaging and an analysis of the SuperAger brains after death show the following brain signature:

MRI imaging showed the anterior cingulate cortex of SuperAgers (31 subjects) was not only significantly thicker than the same area in aged individuals with normal cognitive performance (21 subjects), but also larger than the same area in a group of much younger, middle-aged individuals (ages 50 to 60, 18 subjects). This region is indirectly related to memory through its influence on related functions such as cognitive control, executive function, conflict resolution, motivation and perseverance. 

Analysis of the brains of five SuperAgers showed the anterior cingulate cortex had approximately 87 percent less tangles than age-matched controls and 92 percent less tangles than individuals with mild cognitive impairment. The neurofibrillary brain tangles, twisted fibers consisting of the protein tau, strangle and eventually kill neurons. 

The number of von Economo neurons was approximately three to five times higher in the anterior cingulate of SuperAgers compared with age-matched controls and individuals with mild cognitive impairment.

 “It’s thought that these von Economo neurons play a critical role in the rapid transmission of behaviorally relevant information related to social interactions,” Geula said, “which is how they may relate to better memory capacity.”

Studies like this, will probably have you ask what it takes to be among the SuperAgers. Unfortunately, there aren't yet any clear answers, Emily Rogalski, an assistant research professor at Northwestern has said.

"Genetics are likely to play a role. And, in general, a healthy lifestyle is supportive of good memory. But in our experience, some of our SuperAgers have been smoking a pack of cigarettes for the last 20 years. Others have never touched them. Some go to the gym three to five days a week. Others don't exercise. Some are still working and others have never worked. It seems there might be more than one route to being a SuperAger."


SOURCE  Northwestern University

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 Neuroscience  

An international team led by researchers has successfully determined the location, where memories are generated in the brain with a level of precision never achieved before.

The human brain continuously collects information. However, we have only basic knowledge of how new experiences are converted into lasting memories. Now, an international team led by researchers of the University of Magdeburg and the German Center for Neurodegenerative Diseases (DZNE) has successfully determined the location, where memories are generated with a level of precision never achieved before. The team was able to pinpoint this location down to specific circuits of the human brain.

To this end the scientists used a particularly accurate type of magnetic resonance imaging (MRI) technology. The researchers hope that the results and method of their study might be able to assist in acquiring a better understanding of the effects Alzheimer’s disease has on the brain.

The study was published in the journal Nature Communications.

For the recall of experiences and facts, various parts of the brain have to work together. Much of this interdependence is still undetermined, however, it is known that memories are stored primarily in the cerebral cortex and that the control center that generates memory content and also retrieves it, is located in the brain’s interior.

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This happens in the hippocampus and in the adjacent entorhinal cortex. “It is been known for quite some time that these areas of the brain participate in the generation of memories. This is where information is collected and processed.

"We have been able to locate the generation of human memories to certain neuronal layers within the hippocampus and the entorhinal cortex. We were able to determine which neuronal layer was active. This revealed if information was directed into the hippocampus or whether it traveled from the hippocampus into the cerebral cortex...this is the first time we have been able to show where in the brain the doorway to memory is located."

Our study has refined our view of this situation,” explains 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. “We have been able to locate the generation of human memories to certain neuronal layers within the hippocampus and the entorhinal cortex. We were able to determine which neuronal layer was active. This revealed if information was directed into the hippocampus or whether it traveled from the hippocampus into the cerebral cortex. Previously used MRI techniques were not precise enough to capture this directional information. Hence, this is the first time we have been able to show where in the brain the doorway to memory is located.”

For this study, the scientists examined the brains of persons who had volunteered to participate in a memory test. The researchers used a special type of magnetic resonance imaging technology called 7 Tesla ultra-high field MRI. This enabled them to determine the activity of individual brain regions with unprecedented accuracy.

This work may lead to new findings about Alzheimer's and other neurodegenerative disorders.

“This measuring technique allows us to track the flow of information inside the brain and examine the areas that are involved in the processing of memories in great detail,” comments Düzel. “As a result, we hope to gain new insights into how memory impairments arise that are typical for Alzheimer’s. Concerning dementia, is the information still intact at the gateway to memory? Do troubles arise later on, when memories are processed? We hope to answer such questions.”


SOURCE  German Center for Neurodegenerative Diseases

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 Neuroscience  

New research could lead to the development of new tools to help untangle what happens in the brain during sleep and dreaming. This work is leading to knowledge of  how the brain uses networks to encode short-term memory.

As real as that daydream may seem, its path through your brain runs opposite reality.

Aiming to discern discrete neural circuits, researchers at the University of Wisconsin–Madison have tracked electrical activity in the brains of people who alternately imagined scenes or watched videos.

“A really important problem in brain research is understanding how different parts of the brain are functionally connected. What areas are interacting? What is the direction of communication?” says Barry Van Veen, a UW-Madison professor of electrical and computer engineering.

“We know that the brain does not function as a set of independent areas, but as a network of specialized areas that collaborate."

Van Veen, along with Giulio Tononi, a UW-Madison psychiatry professor and neuroscientist, Daniela Dentico, a scientist at UW–Madison’s Waisman Center, and collaborators from the University of Liege in Belgium, published results recently in the journal NeuroImage. Their work could lead to the development of new tools to help Tononi untangle what happens in the brain during sleep and dreaming, while Van Veen hopes to apply the study’s new methods to understand how the brain uses networks to encode short-term memory.

During imagination, the researchers found an increase in the flow of information from the parietal lobe of the brain to the occipital lobe — from a higher-order region that combines inputs from several of the senses out to a lower-order region.

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In contrast, visual information taken in by the eyes tends to flow from the occipital lobe — which makes up much of the brain’s visual cortex — “up” to the parietal lobe.

“There seems to be a lot in our brains and animal brains that is directional, that neural signals move in a particular direction, then stop, and start somewhere else,” says Van Veen. “I think this is really a new theme that had not been explored.”

"There seems to be a lot in our brains and animal brains that is directional, that neural signals move in a particular direction, then stop, and start somewhere else. I think this is really a new theme that had not been explored."

The researchers approached the study as an opportunity to test the power of electroencephalography (EEG) — which uses sensors on the scalp to measure underlying electrical activity — to discriminate between different parts of the brain’s network. Brains are rarely quiet, though, and EEG tends to record plenty of activity not necessarily related to a particular process researchers want to study.

To zero in on a set of target circuits, the researchers asked their subjects to watch short video clips before trying to replay the action from memory in their heads. Others were asked to imagine traveling on a magic bicycle — focusing on the details of shapes, colors and textures — before watching a short video of silent nature scenes.

Using an algorithm Van Veen developed to parse the detailed EEG data, the researchers were able to compile strong evidence of the directional flow of information.

“We were very interested in seeing if our signal-processing methods were sensitive enough to discriminate between these conditions,” says Van Veen, whose work is supported by the National Institute of Biomedical Imaging and Bioengineering. “These types of demonstrations are important for gaining confidence in new tools.”


SOURCE  University of Wisconsin–Madison

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