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Stunning new maps of myelin-making mouse brain cells advance understanding of nervous system disorders

Johns Hopkins scientists say they have used 3D imaging, special microscopes and artificial intelligence (AI) programs to construct new maps of mouse brains showing a precise location of more than 10 million cells called oligodendrocytes. These cells form myelin, a protective sleeve around nerve cell axons, which speeds transmission of electrical signals and support brain health.

Published online Feb. 18 in Cell and funded by the National Institutes of Health, the maps not only paint a whole-brain picture of how myelin content varies between brain circuits, but also provide insights into how the loss of such cells impacts human diseases such as multiple sclerosis, Alzheimer’s disease and other disorders that affect learning, memory, sensory ability and movement, say the researchers. Although mouse and human brains are not the same, they share many characteristics and most biological processes.

“Our study identifies not only the location of oligodendrocytes in the brain, but also integrates information about gene expression and the structural features of neurons,” says Dwight Bergles, Ph.D., the Diana Sylvestre and Charles Homcy Professor in the Department of Neuroscience at the Johns Hopkins University School of Medicine. “It’s like mapping the location of all the trees in a forest, but also adding information about soil quality, weather and geology to understand the forest ecosystem.”

Astrocytes, not just neurons, found to drive fear memory signals in the amygdala

Picture a star-shaped cell in the brain, stretching its spindly arms out to cradle the neurons around it. That’s an astrocyte, and for a long time, scientists thought its job was caretaking the brain, gluing together neurons, and maintaining neural circuits. But now, a new study reveals that these supposed support cells that are spread all over the brain are as important as neurons in fear memory.

“Astrocytes are interwoven among neurons in the brain, and it seemed unlikely they were there just for housekeeping. We wanted to understand what they’re actually doing—and how they’re shaping neural activity in the process,” said Lindsay Halladay, assistant professor at the University of Arizona Department of Neuroscience and one of the study’s senior authors.

Halladay’s lab collaborated with researchers from the National Institutes of Health for this multi-institutional study, led by Andrew Holmes and Olena Bukalo of the Laboratory of Behavioral and Genomic Neuroscience.

What a zinc gradient in dentin could mean for fillings and tooth health

Teeth are composites of mineral and protein, with a bulk of bony dentin that is highly porous. This structure allows teeth to be both strong and sensitive. Besides calcium and phosphate, teeth contain trace elements such as zinc. Using complementary microscopy imaging techniques, a team from Charité Berlin, TU Berlin and HZB has quantified the distribution of natural zinc along and across teeth in 3 dimensions. The team found that, as porosity in dentin increases towards the pulp, zinc concentration increases 5~10 fold. These results help to understand the influence of widely-used zinc-containing biomaterials (e.g. filling) and could inspire improvements in dental medicine.

The paper is published in the journal VIEW.

Teeth have a complex structure: the dental pulp with the nerves is surrounded by dentin, a porous bony material, covered externally by enamel in the mouth and cementum in the roots. Although dentin is criss-crossed by countless micrometer-sized dentin tubules, teeth can withstand decades of cyclic, repeated forces. The density of the dentinal tubules increases towards the pulp, meaning that the dentin becomes increasingly porous towards the inside.

Will probiotics work for you? Models map gut metabolism to predict success

A new study demonstrates that computer models of gut metabolism can predict which probiotics will successfully establish themselves in a person’s gut and how different prebiotics affect production of health-promoting short-chain fatty acids. The findings are published in PLOS Biology by Sean Gibbons of the Institute for Systems Biology, US, and colleagues.

Probiotic and prebiotic supplements show highly variable results across individuals, making it difficult to predict who will benefit from these interventions. This variability comes from complex interactions between introduced probiotics, each person’s existing gut microbiota, and their diet.

In the new work, researchers first tested a metabolic model on data from two previous studies in which participants diagnosed with type 2 diabetes were given a placebo or probiotic/prebiotic mixture designed to improve glucose control and healthy participants were given a placebo or a probiotic treatment designed to treat recurrent Clostridioides difficile infections, respectively.

Grant supports research into how microglia may spread toxic tau in Alzheimer’s

A paper describing Hopp’s upcoming study published on the CureAlz website, titled, “How Do Microglia Contribute to the Spread of Tau Pathology in Alzheimer’s Disease?”, says that while tau aggregates are a defining feature of Alzheimer’s disease and closely track with brain cell loss, memory problems and cognitive decline, much still isn’t known about how it spreads or what role the brain’s immune system plays in the process.

There is evidence, it says, that toxic forms of tau, which have become “misfolded” or dysfunctional, act like a “bad influence.”

“When they encounter nearby healthy tau proteins, they cause them to misfold as well, triggering a chain reaction that spreads from one brain region to another,” according to the paper. “Microglia … are among the first to encounter these toxic tau ‘seeds.’ Normally, microglia protect the brain by clearing debris and helping repair damage. But growing evidence suggests that microglia may also contribute to tau’s spread by engulfing misfolded tau and inadvertently releasing it, thereby amplifying its harmful effects.”

A researcher with the Glenn Biggs Institute for Alzheimer’s and Neurodegenerative Diseases at UT Health San Antonio has received a two-year, $402,500 grant award from the Cure Alzheimer’s Fund to study how microglia, the brain’s resident immune cells, paradoxically might contribute to the spread of toxic forms of tau protein in the disease.

Sarah C. Hopp, PhD, associate professor of pharmacology with the Biggs Institute and the South Texas Alzheimer’s Disease Research Center, along with her lab have been instrumental in uncovering the behavior of microglia. UT Health San Antonio is the academic health center of The University of Texas at San Antonio.

Starting this month, Hopp’s lab will test the hypothesis that microglial uptake of tau is a key mechanism driving its spread through the brain, and that specific molecular pathways determine whether this process protects or harms neurons. The Cure Alzheimer’s Fund, also known as CureAlz, is a nonprofit organization that funds research “with the highest probability of preventing, slowing or reversing Alzheimer’s disease.”

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Radiation-Induced Optic Neuropathy Following Radiation Therapy for a Recurrent Tuberculum Sellae Meningioma: A Case Report

A new light-based imaging approach has produced an unprecedented chemical map of the Alzheimer’s brain.

Rice University researchers have produced what they describe as the first full, label-free molecular atlas of an Alzheimer’s brain in an animal model. In simple terms, they created a brain-wide “chemical map” that can help scientists study where the disease appears to take hold and how it spreads over time. Alzheimer’s is also a major public health threat, killing more people than breast cancer and prostate cancer combined.

Instead of focusing only on classic pathology markers, the team examined the brain’s underlying chemistry using a light-based imaging approach paired with machine learning. Their study, published in ACS Applied Materials and Interfaces, shows that Alzheimer’s-linked chemical shifts are patchy across the brain rather than uniform. It also suggests those shifts extend beyond amyloid plaques, the best-known feature of the disease.

The “Most Effective” Treatment for Osteoarthritis May Be Less Helpful Than Thought

A sweeping review of clinical evidence casts doubt on one of the most commonly prescribed treatments for osteoarthritis. For millions of people living with osteoarthritis, being told to exercise is almost a reflex in medical care. But a new analysis suggests that, when it comes to easing joint pa

Health impacts of micro- and nanoplastic ingestion

The carcinogenic consequences of the plastic pollution crisis.

This Viewpoint by Jason A. Somarelli, Jason W. Arnold & Andrew B. West discusses the health impacts of micro-and nanoplastic ingestion: microplastics.

Address correspondence to: Jason A. Somarelli, 3,044 Genome Sciences Research Building I, 905 S. Lasalle St., Duke University Medical School, Durham, North Carolina 27,710, USA. Email: [email protected].

Researcher skeptical of ‘Havana syndrome’ tested secret weapon on himself

“Working in strict secrecy, a government scientist in Norway built a machine capable of emitting powerful pulses of microwave energy and, in an effort to prove such devices are harmless to humans, in 2024 tested it on himself. He suffered neurological symptoms similar to those of ”Havana syndrome,” the unexplained malady that has struck hundreds of U.S. spies and diplomats around the world.

The bizarre story, described by four people familiar with the events, is the latest wrinkle in the decade-long quest to find the causes of Havana syndrome, whose sufferers experience long-lasting effects including cognitive challenges, dizziness and nausea. The U.S. government calls the events Anomalous Health Incidents (AHIs).

The secret test in Norway has not been previously reported. The Norwegian government told the CIA about the results, two of the people said, prompting at least two visits in 2024 to Norway by Pentagon and White House officials.

The CIA investigated a Norwegian government experiment with a pulsed-energy machine in which a researcher built and tested a ”Havana syndrome” device on himself.

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