Brain Research: Physical activity may leave the brain more open to change ♦ Negative beliefs about aging predict Alzheimer's disease ♦ Discovery puts designer dopamine neurons within reach

Potential biochemical mechanism underlying long-term memories identified During the holidays, we often remember the past and create new memories. But, why do some memories fade away while others last forever? Scientists have identified a possible biochemical mechanism by which the specialized brain cells known as neurons create and maintain a long-term memory from a fleeting experience.

Negative beliefs about aging predict Alzheimer's disease Individuals who hold negative beliefs about aging are more likely to have brain changes associated with Alzheimer's disease.

Physical activity may leave the brain more open to change Learning, memory, and brain repair depend on the ability of our neurons to change with experience. Now, researchers have evidence that exercise may enhance this essential plasticity of the adult brain.

Discovery puts designer dopamine neurons within reach Parkinson's disease researchers have developed a way to ramp up the conversion of skin cells into dopamine neurons. They have identified -- and found a way to overcome -- a key obstacle to such cellular conversions

Health Research: What your father ate before you were born could influence your health ♦ Cell suicide prevention squad ♦ Certain herpes viruses can infect human neurons

What your father ate before you were born could influence your health There is increasing evidence that parents' lifestyle and the environment they inhabit even long before they have children may influence the health of their offspring. A new study sheds light on how.

Cell suicide prevention squad Recent research has shown that the cells in our bodies teeter on the brink of death. They possess intricate molecular mechanisms that promote either suicide or survival. The concept is known as programmed cell death (PCD). Since the early 2000s, when PCD was confirmed, research has focused mainly on finding genes and proteins that trigger it. however, processes aiding cell survival have not been well understood.

No two faces are the same Researchers have been studying a likely congenital dysfunction that is characterized by the inability to recognize familiar faces. The study's findings are crucial, not just for our understanding of face recognition, but also because they allow us to understand the processes behind the recognition of any visually presented object.

Certain herpes viruses can infect human neurons Epstein-Barr virus and Kaposi’s sarcoma-associated herpes virus can infect and replicate in cultured and primary neurons, report scientists

Health News: Repairing neurons with light, ♦ Self-healing sensor brings 'electronic skin' closer to reality ♦ Obesity and type 2 diabetes harm bone healt

Vitamin D deficiency may limit immune recovery in HIV-positive adults Low levels of vitamin D may limit the effectiveness of HIV treatment in adults, a researcher has found. An 18-month longitudinal study was conducted in which the immune status of 398 HIV-positive adults The researchers, through observation, related the rise in immune function to whether or not individuals had adequate levels of vitamin D

Self-healing sensor brings 'electronic skin' closer to reality Scientists have developed a self-healing, flexible sensor that mimics the self-healing properties of human skin. Incidental scratches or cuts to the sensors "heal" themselves in less than one day.

Repairing neurons with light Scientists have succeeded in stimulating the regeneration of injured neurons in living fish by the use of light. To this end, they employed so-called Optogenetics, i.e. light inducible protein activation.

Obesity and type 2 diabetes harm bone health In a new animal study, researchers examined how the development of obesity and insulin resistance contribute to bone-fracture risk and whether exercise prevents weight gain and diabetes and protects bone health. They found obesity and type 2 diabetes negatively affected bone, but exercise prevented weight gain and diabetes and increased bone strength. These findings could inform interventions to improve bone health among individuals with obesity and type 2 diabetes.

Brain Research Bacterial protein can help convert stem cells into neurons ♦ Yin and yang of serotonin neurons in mood regulation ♦ Nanocarriers may carry new hope for brain cancer therapy

Nanocarriers may carry new hope for brain cancer therapy A new family of nanocarriers, called '3HM,' has been developed and meets all the size and stability requirements for effectively delivering therapeutic drugs to the brain for the treatment of a deadly form of cancer known as glioblastoma multiforme.

Yin and yang of serotonin neurons in mood regulation Low levels of serotonin in the brain are known to play a role in depression and anxiety, and it is customary to treat these disorders with medications that increase the amount of this neurotransmitter. It appears that neighboring serotonin-producing brainstem regions exert different and sometimes opposing effects on behavior.

Bacterial protein can help convert stem cells into neurons As the recipe book for turning stem cells into other types of cells keeps growing larger, the search for the perfect, therapeutically relevant blend of differentiation factors is revealing some interesting biology. A protein in E. coli bacteria combined with small molecules can act synergistically to push pluripotent cells into functional neurons.

How exercise may energize brain cell function: As we age or develop neurodegenerative diseases such as Alzheimer's, our brain cells may not produce sufficient energy to remain fully functional. Researchers have discovered that an enzyme called SIRT3 that is located in mitochondria — the cell's powerhouse — may protect mice brains against the kinds of stresses believed to contribute to energy loss. Furthermore, mice that ran on a wheel increased their levels of this protective enzyme.

Bacterial Research:Superbug infection greatest increase in children ages one to five ♦ Biologists discover bacteria communicate like neurons in the brain ♦ Staphylococcus aureus Achilles' heel

First synthetic model of a bacterial outer membrane will support antibiotic development Scientists have developed a model of the outer membrane of the bacteria E. coli (Escherichia coli) providing a brand new tool for developing new antibiotics and other drugs in the fight against infections

Superbug infection greatest increase in children ages one to five Children are becoming infected with the highly fatal antibiotic resistant bacteria CRE at a much higher rate than the recent past, according to a data analysis in the United States.

Biologists discover bacteria communicate like neurons in the brain Biologists have discovered that bacteria -- often viewed as lowly, solitary creatures -- are actually quite sophisticated in their social interactions and communicate with one another through similar electrical signaling mechanisms as neurons in the human brain.

Staphylococcus aureus Achilles' heel Staphylococcus aureus is both a transient skin colonizer and a formidable human pathogen, ranking amongst the leading causes of skin and soft tissue infections, as well as severe pneumonia. Scientists attempt to work out new strategies to fight against this pathogen, of which numerous strains are now resistant to antibiotic treatments.

Unified approach to combating several bacterial diseases Structural similarities have been discovered among bacteria of various types that create the possibility of using similar approaches to fight the infections they cause

Brain Research: Discovering the brain’s memory switch ♦ : Your visual cortex is making decisions ♦ Discovering the brain’s memory switch

A natural history of neurons Our brain cells have different genomes from one another. The study shows for the first time that mutations in somatic cells -- that is, any cell in the body except sperm and eggs -- are present in significant numbers in the brains of healthy people. These mutations appear to occur more often in the genes a neuron uses most. Patterns of mutation allow researchers to trace brain cell lineages.

Discovering the brain’s memory switch Scientists have recorded evidence of the brain turning off its memory inhibitor to make new memories

Single neuron may carry over 1,000 mutations A single neuron in a normal adult brain likely has more than a thousand genetic mutations that are not present in the cells that surround it, according to new research. The majority of these mutations appear to arise while genes are in active use, after brain development is complete.

Surprise: Your visual cortex is making decisions The part of the brain responsible for seeing is more powerful than previously believed. In fact, the visual cortex can essentially make decisions just like the brain's traditional 'higher level' areas.

Virus-drug combination shows improved effectiveness against brain tumor cells A rabbit virus currently being developed for cancer therapy can be paired with one of several existing drugs to deliver a more potent punch to a deadly type of brain tumor cell,

Brain Research: How neurons remember ♦ Infants use expectations to shape their brains ♦ Manipulating molecule in the brain improves stress response

Infants use expectations to shape their brains Infants can use their expectations about the world to rapidly shape their developing brains, researchers have found. A series of experiments with infants ages 5 to 7 months has shown that portions of babies' brains responsible for visual processing respond not just to the presence of visual stimuli, but also to the mere expectation of visual stimuli.

Poverty's most insidious damage is to a child's brain An alarming 22 percent of U.S. children live in poverty, which can have long-lasting negative consequences on brain development, emotional health and academic achievement. Now, even more compelling evidence has been provided suggesting that growing up in poverty has detrimental effects on the brain.

How neurons remember Scientists have discovered mechanism at the level of the individual neurons that may play a role in the formation of memory. They have determined that back-propagating electrical impulses serve to activate a receptor inside the cell, thereby resulting in long-term changes in the calcium response in specific neuronal compartments.

Manipulating molecule in the brain improves stress response, new target for depression treatment Increasing the levels of a signaling molecule found in the brain can positively alter response to stress, revealing a potential new therapeutic target for treatment of depression,

Unexpected role for stem cells in the brain

NIH scientists find that restocking new cells in the brain’s center for smell maintains crucial circuitry

For decades, scientists thought that neurons in the brain were born only during the early development period and could not be replenished.  More recently, however, they discovered cells with the ability to divide and turn into new neurons in specific brain regions. The function of these neural progenitor cells remains an intense area of research. Scientists at the National Institutes of Health (NIH) report that newly formed brain cells in the mouse olfactory system — the area that processes smells — play a critical role in maintaining proper connections. The results were published in the October 8 issue of the Journal of Neuroscience.

“This is a surprising new role for brain stem cells and changes the way we view them,” said Leonardo Belluscio, Ph.D., a scientist at NIH’s National Institute of Neurological Disorders and Stroke (NINDS) and lead author of the study.

The olfactory bulb is located in the front of the brain and receives information directly from the nose about odors in the environment. Neurons in the olfactory bulb sort that information and relay the signals to the rest of the brain, at which point we become aware of the smells we are experiencing. Olfactory loss is often an early symptom in a variety of neurological disorders, including Alzheimer’s and Parkinson’s diseases.

In a process known as neurogenesis, adult-born neural progenitor cells are generated in the subventricular zone deep in the brain and migrate to the olfactory bulb where they assume their final positions. Once in place, they form connections with existing cells and are incorporated into the circuitry.

Dr. Belluscio, who studies the olfactory system, teamed up with Heather Cameron, Ph.D., a neurogenesis researcher at the NIH’s National Institute of Mental Health, to better understand how the continuous addition of new neurons influences the circuit organization of the olfactory bulb. Using two types of specially engineered mice, they were able to specifically target and eliminate the stem cells that give rise to these new neurons in adults, while leaving other olfactory bulb cells intact. This level of specificity had not been achieved previously.    

In the first set of mouse experiments, Dr. Belluscio’s team first disrupted the organization of olfactory bulb circuits by temporarily plugging a nostril in the animals, to block olfactory sensory information from entering the brain. His lab previously showed that this form of sensory deprivation causes certain projections within the olfactory bulb to dramatically spread out and lose the precise pattern of connections that show under normal conditions. These studies also showed that this widespread disrupted circuitry could re-organize itself and restore its original precision once the sensory deprivation was reversed.

However, in the current study, Dr. Belluscio’s lab reveals that once the nose is unblocked, if new neurons are prevented from forming and entering the olfactory bulb, the circuits remain in disarray. “We found that without the introduction of the new neurons, the system could not recover from its disrupted state,” said Dr. Belluscio.

To further explore this idea, his team also eliminated the formation of adult-born neurons in mice that did not experience sensory deprivation. They found that the olfactory bulb organization began to break down, resembling the pattern seen in animals blocked from receiving sensory information from the nose. And they observed a relationship between the extent of stem cell loss and amount of circuitry disruption, indicating that a greater loss of stem cells led to a larger degree of disorganization in the olfactory bulb.

According to Dr. Belluscio, it is generally assumed that the circuits of the adult brain are quite stable and that introducing new neurons alters the existing circuitry, causing it to re-organize. “However, in this case, the circuitry appears to be inherently unstable requiring a constant supply of new neurons not only to recover its organization following disruption but also to maintain or stabilize its mature structure. It’s actually quite amazing that despite the continuous replacement of cells within this olfactory bulb circuit, under normal circumstances its organization does not change,” he said.

Dr. Belluscio and his colleagues speculate that new neurons in the olfactory bulb may be important to maintain or accommodate the activity-dependent changes in the system, which could help animals adapt to a constantly varying environment.

“It’s very exciting to find that new neurons affect the precise connections between neurons in the olfactory bulb. Because new neurons throughout the brain share many features, it seems likely that neurogenesis in other regions, such as the hippocampus, which is involved in memory, also produce similar changes in connectivity,” said Dr. Cameron.

The underlying basis of the connection between neurological disease and changes in the olfactory system is also unknown but may come from a better understanding of how the sense of smell works. “This is an exciting area of science,” said Dr. Belluscio, “I believe the olfactory system is very sensitive to changes in neural activity and given its connection to other brain regions, it could lend insight into the relationship between olfactory loss and many brain disorders.”

Bioengineers Create Functional 3D Brain-like Tissue

Bioengineers have created three-dimensional brain-like tissue that functions like and has structural features similar to tissue in the rat brain and that can be kept alive in the lab for more than two months.

Confocal microscope image of neurons (greenish yellow) attached to silk-based scaffold (blue). The neurons formed functional networks throughout the scaffold pores (dark areas). Image courtesy of Tufts University.

As a first demonstration of its potential, researchers used the brain-like tissue to study chemical and electrical changes that occur immediately following traumatic brain injury and, in a separate experiment, changes that occur in response to a drug. The tissue could provide a superior model for studying normal brain function as well as injury and disease, and could assist in the development of new treatments for brain dysfunction.

The brain-like tissue was developed at the Tissue Engineering Resource Center at Tufts University, Boston, which is funded by the National Institute of Biomedical Imaging and Bioengineering (NIBIB) to establish innovative biomaterials and tissue engineering models.  David Kaplan, Ph.D., Stern Family Professor of Engineering at Tufts University is director of the center and led the research efforts to develop the tissue.

Currently, scientists grow neurons in petri dishes to study their behavior in a controllable environment. Yet neurons grown in two dimensions are unable to replicate the complex structural organization of brain tissue, which consists of segregated regions of grey and white matter. In the brain, grey matter is comprised primarily of neuron cell bodies, while white matter is made up of bundles of axons, which are the projections neurons send out to connect with one another. Because brain injuries and diseases often affect these areas differently, models are needed that exhibit grey and white matter compartmentalization.

Recently, tissue engineers have attempted to grow neurons in 3D gel environments, where they can freely establish connections in all directions. Yet these gel-based tissue models don’t live long and fail to yield robust, tissue-level function. This is because the extracellular environment is a complex matrix in which local signals establish different neighborhoods that encourage distinct cell growth and/or development and function.  Simply providing the space for neurons to grow in three dimensions is not sufficient.

Diagram of scaffold donut showing grey-white matter compartmentalization. Rat neurons attached to the scaffold (donut ring) and also sent axons (labeled with green fluorescence) through the collagen gel-filled center.

Now, in the Aug. 11th early online edition of the journal Proceedings of the National Academy of Sciences, a group of bioengineers report that they have successfully created functional 3D brain-like tissue that exhibits grey-white matter compartmentalization and can survive in the lab for more than two months.

“This work is an exceptional feat,” said Rosemarie Hunziker, Ph.D., program director of Tissue Engineering at NIBIB. “It combines a deep understand of brain physiology with a large and growing suite of bioengineering tools to create an environment that is both necessary and sufficient to mimic brain function.”

The key to generating the brain-like tissue was the creation of a novel composite structure that consisted of two biomaterials with different physical properties: a spongy scaffold made out of silk protein and a softer, collagen-based gel. The scaffold served as a structure onto which neurons could anchor themselves, and the gel encouraged axons to grow through it.

To achieve grey-white matter compartmentalization, the researchers cut the spongy scaffold into a donut shape and populated it with rat neurons. They then filled the middle of the donut with the collagen-based gel, which subsequently permeated the scaffold. In just a few days, the neurons formed functional networks around the pores of the scaffold, and sent longer axon projections through the center gel to connect with neurons on the opposite side of the donut. The result was a distinct white matter region (containing mostly cellular projections, the axons) formed in the center of the donut that was separate from the surrounding grey matter (where the cell bodies were concentrated).  

Over a period of several weeks, the researchers conducted experiments to determine the health and function of the neurons growing in their 3D brain-like tissue and to compare them with neurons grown in a collagen gel-only environment or in a 2D dish.

Image of silk-based scaffold taken with a scanning electron microscope reveals its porous, sponge-like composition. Image courtesy of Tufts University.

The researchers found that the neurons in the 3D brain-like tissues had higher expression of genes involved in neuron growth and function. In addition, the neurons grown in the 3D brain-like tissue maintained stable metabolic activity for up to five weeks, while the health of neurons grown in the gel-only environment began to deteriorate within 24 hours. In regard to function, neurons in the 3D brain-like tissue exhibited electrical activity and responsiveness that mimic signals seen in the intact brain, including a typical electrophysiological response pattern to a neurotoxin.

Because the 3D brain-like tissue displays physical properties similar to rodent brain tissue, the researchers sought to determine whether they could use it to study traumatic brain injury. To simulate a traumatic brain injury, a weight was dropped onto the brain-like tissue from varying heights. The researchers then recorded changes in the neurons’ electrical and chemical activity, which proved similar to what is ordinarily observed in animal studies of traumatic brain injury.

Kaplan says the ability to study traumatic injury in a tissue model offers advantages over animal studies, in which measurements are delayed while the brain is being dissected and prepared for experiments.

“With the system we have, you can essentially track the tissue response to traumatic brain injury in real time,” said Kaplan. “Most importantly, you can also start to track repair and what happens over longer periods of time.”

Kaplan emphasized the importance of the brain-like tissue’s longevity for studying other brain disorders. “The fact that we can maintain this tissue for months in the lab means we can start to look at neurological diseases in ways that you can’t otherwise because you need long timeframes to study some of the key brain diseases,” he said.

Hunziker added, “Good models enable solid hypotheses that can be thoroughly tested. The hope is that use of this model could lead to an acceleration of therapies for brain dysfunction as well as offer a better way to study normal brain physiology.”

Kaplan and his team are looking into how they can make their tissue model more brain-like.  In this recent report, the researchers demonstrated that they can modify their donut scaffold so that it consists of six concentric rings, each able to be populated with different types of neurons. Such an arrangement would mimic the six layers of the human brain cortex, in which different types of neurons exist.

As part of the funding agreement for the Tissue Engineering Resource Center, NIBIB requires that new technologies generated at the center be shared with the greater biomedical research community.

“We look forward to building collaborations with other labs that want to build on this tissue model,” said Kaplan.

3/28/14 Health News: Slaughterhouse Shutdown, Operator Arrested For Animal Cruelty ♦ Protein May Hold the Key to Who Gets Alzheimer’s ♦ Chronic Sleep Loss Could Lead to Loss of Brain Neurons,

Slaughterhouse Shutdown, Operator Arrested For Animal Cruelty

The Animal Recovery Mission (ARM), a non-Profit investigative animal welfare organization based in Miami Beach, said undercover videos were taken on December 24, 2013 when their personnel entered onto the property posing as customers. According to police, another video was taken on December 30, 2013. Continue Reading

Protein May Hold the Key to Who Gets Alzheimer’s

It is one of the big scientific mysteries of Alzheimer’s disease: Why do some people whose brains accumulate the plaques and tangles so strongly associated with Alzheimer’s not develop the disease? Now, a series of studies by Harvard scientists suggests a possible answer, one that could lead to new treatments if confirmed by other research. The memory and thinking problems of Alzheimer’s disease and other dementias, which affect an estimated seven million Americans, may be related to a failure in the brain’s stress response system, the new research suggests. If this system is working well, it can protect the brain from abnormal Alzheimer’s proteins; if it gets derailed, critical areas of the brain start degenerating. “This is an extremely important study,” said Li-Huei Tsai, director of the Picower Institute for Learning and Memory at the Massachusetts Institute of Technology, who wrote “This is the first study that is really starting to provide a plausible pathway to explain why some people are more vulnerable to Alzheimer’s than other people.” Continue Reading

Chronic Sleep Loss Could Lead to Loss of Brain Neurons,

Mice study suggests chronic sleep deprivation could have more lasting effects on the brain than previously realized, according to a new study in mice. Researchers from the University of Pennsylvania Perelman School of Medicine and Peking University found that chronic sleep loss is associated with injury and loss of locus coeruleus (LC) neurons in the brain, which are needed for alertness and optimal thinking Continue Reading