Neighboring synapses shape learning and memory

A mathematical model reveals how interactions between neighboring contact sites of nerve cells influence learning.
Image Credit: University of Basel, Biozentrum

A researcher at the University of Basel, in collaboration with a colleague in Austria, has developed a new model that provides a holistic view on how our brain manages to learn quickly and forms stable, long-lasting memories. Their study sheds light on the crucial role of interactions among neighboring contact sites of nerve cells for brain plasticity – the brain’s ability to adapt to new experiences.

In 1949, the Canadian psychologist Donald O. Hebb described that connections between neurons become stronger when the neurons are active at the same time and that strengthened connections facilitate signal transmission. The ability of our brain to modify the connections between neurons is fundamental for learning and memory.

 “It has long been assumed that these adaptations occur mostly on a one-on-one basis at specific synapses, the contact sites between two neurons”, explains Dr. Everton Agnes from the Biozentrum, University of Basel. “Interestingly, synapses that undergo changes also affect multiple neighboring synapses.” As these complex synaptic interactions are difficult to investigate experimentally, Agnes and his colleague Prof. Tim Vogels from the Institute of Science and Technology Austria have built a theoretical model to disentangle this phenomenon, also known as co-dependency. Their work has recently been published in Nature Neuroscience.

World's first high-resolution brain developed by 3D printer

Franziska Chalupa-Gantner and Aleksandr Ovsianikov at work.
Photo Credit: Courtesy of Technische Universität Wien

In a joint project between TU Wien and MedUni Vienna, the world's first 3D-printed "brain phantom" has been developed, which is modelled on the structure of brain fibres and can be imaged using a special variant of magnetic resonance imaging (dMRI). As a scientific team led by TU Wien and MedUni Vienna has now shown in a study, these brain models can be used to advance research into neurodegenerative diseases such as Alzheimer's, Parkinson's and multiple sclerosis. The research work was published in the journal Advanced Materials Technologies.

Magnetic resonance imaging (MRI) is a widely used diagnostic imaging technique that is primarily used to examine the brain. MRI can be used to examine the structure and function of the brain without the use of ionizing radiation. In a special variant of MRI, diffusion-weighted MRI (dMRI), the direction of the nerve fibers in the brain can also be determined. However, it is very difficult to correctly determine the direction of nerve fibers at the crossing points of nerve fiber bundles, as nerve fibers with different directions overlap there. In order to further improve the process and test analysis and evaluation methods, an international team in collaboration with the TU Wien and the Medical University of Vienna developed a so-called "brain phantom", which was produced using a high-resolution 3D printing process.

Icy impacts: Planetary scientists use physics and images of impact craters to gauge the thickness of ice on Europa

Brandon Johnson and his team study impact craters around the solar system for clues about planetary bodies’ history and composition.
Photo Credit: Rebecca Robinos / Purdue University

Sometimes planetary physics is like being in a snowball fight. Most people, if handed an already-formed snowball, can use their experience and the feel of the ball to guess what kind of snow it is comprised of: packable and fluffy, or wet and icy.

Using nearly the same principles, planetary scientists have been able to study the structure of Europa, Jupiter’s icy moon.

Europa is a rocky moon, home to saltwater oceans twice the volume of Earth’s, encased in a shell of ice. Scientists have long thought that Europa may be one of the best places in our solar system to look for nonterrestrial life. The likelihood and nature of that life, though, heavily depend on the thickness of its icy shell, something astronomers have not yet been able to measure.

A team of planetary science experts including Brandon Johnson, an associate professor, and Shigeru Wakita, a research scientist, in the Department of Earth, Atmospheric, and Planetary Sciences in Purdue University’s College of Science, announced in a new paper published in Science Advances that Europa’s ice shell is at least 20 kilometers thick.

Adding ribociclib to hormone therapy reduces the risk of breast cancer recurrence

Photo Credit: National Cancer Institute

A new treatment approach that combines a targeted therapy drug with hormone therapy significantly increased the amount of time a person with stage 2 or 3 HR-positive, HER2-negative early breast cancer lives without the cancer returning, according to a new study co-led by UCLA Health Jonsson Comprehensive Cancer Center investigators.

The team found adding ribociclib, a drug that belongs to a class of CDK4/6 inhibitors, to standard hormone therapy not only improved invasive-free survival in women with this type of early-stage breast cancer, but also improves distant disease-free survival and recurrence-free survival.

The results were published today in the New England Journal of Medicine and findings were presented last year at the American Society of Clinical Oncology Annual Meeting in Chicago.

“We found that adding ribociclib to the standard hormone therapy resulted in a relative reduction in the recurrence rate by as much as 25%,” said first author of the study Dr. Dennis Slamon, chair of hematology-oncology at the David Geffen School of Medicine at UCLA and director of clinical and translational research at the UCLA Health Jonsson Comprehensive Cancer Center. “And that’s huge for this the group of patients, who make up 70% to 75% of breast cancer cases.”

Many patients with this type of breast cancer are treated with surgery, and in some cases with radiation and chemotherapy, followed by endocrine therapy for up to 10 years to help reduce their risk of recurrence.

Hypoxia is widespread and increasing in the ocean off the Pacific Northwest coast

In late August, OSU's Jack Barth and his colleagues deployed a glider that traversed Oregon’s near-shore waters from Astoria to Coos Bay and measured the oxygen levels through the water column, and beamed the data back to OSU computers.
Photo Credit: Courtesy of Jack Barth.

Low oxygen conditions that pose a significant threat to marine life are widespread and increasing in coastal Pacific Northwest ocean waters as the climate warms, a new study shows.

Researchers found that in 2021, more than half the continental shelf off the Pacific Northwest coast experienced the low-oxygen condition known as hypoxia, said the study’s lead author, Jack Barth of Oregon State University.

“We’ve known that low oxygen conditions are increasing based on single points of study in the past, but this confirms that these conditions are occurring across Pacific Northwest coastal waters,” said Barth, an oceanography professor in the College of Earth, Ocean, and Atmospheric Sciences. “The 2021 season was unusually strong compared to past years but with climate change, we are headed in a direction where this may be the norm.”

The new study, published recently in Nature Scientific Reports, is based on data collected by an unprecedented number of research vessels and autonomous underwater gliders that were collecting measurements in the ocean during summer 2021.

New technology improves space weather monitoring

The Compact Space Plasma Analyzer will improve space weather prediction.
Photo Credit: Courtesy of Los Alamos National Laboratory

Peaceful though it may seem from Earth, space is beset by “weather” that can prove perilous for the sensitive — and expensive — technology aboard the spacecraft and satellites increasingly populating the realms outside our atmosphere. To meet that challenge, Los Alamos National Laboratory researchers have developed the Compact Space Plasma Analyzer, a small and cost-efficient space sensor capable of measuring space weather, which will help protect technology in orbit.

“Space weather, which is made up of charged particles from the sun, presents a range of challenges concerning the design, development and operation of satellites and spacecraft,” said Carlos Maldonado, principal investigator of the Compact Space Plasma Analyzer and a researcher in the Lab’s Space Science and Applications group. “Of particular interest to the space community are the interactions between space systems operating in plasma environments, which can lead to potentially hazardous levels of differential charging and cause interference for GPS and communication signals.”

A long-standing goal in the space weather community is to advance the capability to predict space weather events days in advance, in the same way that terrestrial weather forecasting enables one to anticipate a week of sunshine or snow.

Natural recycling at the origin of life

Volcanic freshwater lakes, similar to those found in Iceland today, offered a favorable niche on an early earth. The low-salt, alkaline conditions enabled early RNA replication.
Photo Credit: © Dieter Braun

How was complex life able to develop on the inhospitable early Earth? At the beginning there must have been ribonucleic acid (RNA) to carry the first genetic information. To build up complexity in their sequences, these biomolecules need to release water. On the early Earth, which was largely covered in seawater, that was not so easy to do. In a paper recently published in the Journal of the American Chemical Society (JACS), researchers from the team of LMU professor Dieter Braun have shown that in RNA’s struggle with the surrounding water, its natural recycling capabilities and the right ambient conditions could have been decisive.

“The building blocks of RNA release a water molecule for every bond they form in a growing RNA chain,” explains Braun, spokesperson for the Collaborative Research Centre (CRC) Molecular Evolution in Prebiotic Environments and coordinator at the ORIGINS Excellence Cluster. “When, conversely, water is added to an RNA molecule, the RNA building blocks are fed back into the prebiotic pool.” This turnover of water works particularly well under low saline conditions with high pH levels. “Our experiments indicate that life could emerge from a very small set of molecules, under conditions such as those prevailing on volcanic islands on the early Earth,” says Adriana Serrão, lead author of the study.

Study reveals how pH affects the ability of ulcer bacteria to attach

Anna Åberg and Anna Arnqvist Björklund.
Photo Credit: Mattias Pettersson

A study by Anna Arnqvist's research group at Umeå University reveals molecular details about the gastric pathogen Helicobacter pylori's ability to bind to an inflamed stomach and how this is controlled by the stomach's pH. Increased understanding of how H. pylori bacteria can cause a persistent lifelong infection is an important piece of the puzzle in order to ultimately identify the characteristics that contribute to disease.

When the stomach becomes infected with the gastric pathogen Helicobacter pylori, the infection lasts for life if it is left untreated. The infection can cause peptic ulcer disease as well as stomach cancer. The environment within the stomach undergoes continuous changes, requiring the bacteria to adapt by adjusting the expression of certain proteins based on the prevailing conditions.

It is commonly assumed that the stomach has a low pH. However, the pH levels vary significantly, ranging from the highly acidic environment in the stomach lumen to largely neutral conditions at the outermost layer of the stomach epithelial cells, which is protected by a mucus layer. It is in the mucus layer or tightly attached to the outermost cell layer that most H. pylori bacteria are found. The expression of many genes is regulated in response to pH, causing the bacterium to produce varying amounts of proteins depending on the pH of its surroundings.

Oxford researchers uncover remarkable archive of ancient human brains

Fragments of brain from an individual buried in a Victorian workhouse cemetery (Bristol, UK), some 200 years ago. No other soft tissue survived amongst the bones, which were dredged from the heavily waterlogged grave.
Photo Credit: Alexandra L. Morton-Hayward.

A new study conducted by researchers at the University of Oxford has challenged previously held views that brain preservation in the archaeological record is extremely rare. The team carried out the largest study to date of the global archaeological literature about preserved human brains to compile an archive that exceeds 20-fold the number of brains previously compiled. The findings have been published today in the Proceedings of the Royal Society B.

Soft tissue preservation in the geological record is relatively rare, and, except where deliberate intervention halts the process of decay (for instance, during embalming or freezing), the survival of entire organs is particularly unusual. The spontaneous preservation of the brain in the absence of any other soft tissues - that is, the brain’s survival amongst otherwise skeletonized remains - has historically been regarded as a ‘one-of-a kind’ phenomenon. This new research reveals, however, that nervous tissues actually persist in much greater abundances than traditionally thought, assisted by conditions that prevent decay.

Craving snacks after a meal? It might be food-seeking neurons, not an overactive appetite

The discovery of a circuit in the brain of mice that makes them seek fatty food, even when they are not hungry, could have implications for future understanding of and treatment for human eating disorders.
Photo Credit: Annie Spratt

People who find themselves rummaging around in the refrigerator for a snack not long after they’ve eaten a filling meal might have overactive food-seeking neurons, not an overactive appetite.

UCLA psychologists have discovered a circuit in the brain of mice that makes them crave food and seek it out, even when they are not hungry. When stimulated, this cluster of cells propels mice to forage vigorously and to prefer fatty and pleasurable foods like chocolate over healthier foods like carrots.

People possess the same kinds of cells, and if confirmed in humans, the finding could offer new ways of understanding eating disorders.

The report, published in the journal Nature Communications, is the first to find cells dedicated to food-seeking in a part of the mouse brainstem usually associated with panic, but not with feeding.

“This region we’re studying is called the periaqueductal gray (PAG), and it is in the brainstem, which is very old in evolutionary history and because of that, it is functionally similar between humans and mice,” said corresponding author Avishek Adhikari, a UCLA associate professor of psychology. “Although our findings were a surprise, it makes sense that food-seeking would be rooted in such an ancient part of the brain, since foraging is something all animals need to do.”