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Comment by Dr. Krishna Kumari Challa on December 30, 2022 at 10:02am

In addition to matching nature better, the synaptic plasticity models also conferred other benefits that likely matter to real brains. One was that the plasticity models retained information in their synaptic weightings even after as many as half of the artificial neurons were "ablated." The persistent activity models broke down after losing just 10–20 percent of their synapses. And just spiking occasionally requires less energy than spiking persistently.

Furthermore, quick bursts of spiking rather than persistent spiking leaves room in time for storing more than one item in memory. Research has shown that people can hold up to four different things in working memory. 

Leo Kozachkov et al, Robust and brain-like working memory through short-term synaptic plasticity, PLOS Computational Biology (2022). DOI: 10.1371/journal.pcbi.1010776

Part 2

Comment by Dr. Krishna Kumari Challa on December 30, 2022 at 9:57am

Holding information in mind may mean storing it among synapses

Between the time you read the Wi-Fi password off the café's menu board and the time you can get back to your laptop to enter it, you have to hold it in mind. If you've ever wondered how your brain does that, you are asking a question about working memory that has researchers have strived for decades to explain. Now  neuroscientists have published a key new insight to explain how it works.

In a study in PLOS Computational Biology, scientists compared measurements of brain cell activity in an animal performing a working memory task with the output of various computer models representing two theories of the underlying mechanism for holding information in mind. The results strongly favoured the newer notion that a network of neurons stores the information by making short-lived changes in the pattern of their connections, or synapses, and contradicted the traditional alternative that memory is maintained by neurons remaining persistently active (like an idling engine).

While both models allowed for information to be held in mind, only the versions that allowed for synapses to transiently change connections ("short-term synaptic plasticity") produced neural activity patterns that mimicked what was actually observed in real brains at work. The idea that brain cells maintain memories by being always "on" may be simpler, but it doesn't represent what nature is doing and can't produce the sophisticated flexibility of thought that can arise from intermittent neural activity backed up by short-term synaptic plasticity.

You need these kinds of mechanisms to give working memory activity the freedom it needs to be flexible. If working memory was just sustained activity alone, it would be as simple as a light switch. But working memory is as complex and dynamic as our thoughts.

Using artificial neural networks with short-term synaptic plasticity, scientists show that synaptic activity (instead of neural activity) can be a substrate for working memory. The important takeaway from this paper is: these 'plastic' neural network models are more brain-like, in a quantitative sense, and also have additional functional benefits in terms of robustness.

Part 1

Comment by Dr. Krishna Kumari Challa on December 29, 2022 at 12:49pm

Brain area necessary for fluid intelligence identified

A team of researchers have mapped the parts of the brain that support our ability to solve problems without prior experience—otherwise known as fluid intelligence.

Fluid intelligence is arguably the defining feature of human cognition. It predicts educational and professional success, social mobility, health, and longevity. It also correlates with many cognitive abilities such as memory.

Fluid intelligence is thought to be a key feature involved in "active thinking"—a set of complex mental processes such as those involved in abstraction, judgment, attention, strategy generation and inhibition. These skills can all be used in everyday activities.

Despite its central role in human behavior, fluid intelligence remains contentious, with regards to whether it is a single or a cluster of cognitive abilities, and the nature of its relationship with the brain. To establish which parts of the brain are necessary for a certain ability, researchers must study patients in whom that part is either missing or damaged. Such "lesion-deficit mapping" studies are difficult to conduct owing to the challenge of identifying and testing patients with focal brain injury. Consequently, previous studies have mainly used functional imaging (fMRI) techniques—which can be misleading.

The new study investigated 227 patients who had suffered either a brain tumour or stroke to specific parts of the brain, using the Raven Advanced Progressive Matrices (APM): the best-established test of fluid intelligence. The test contains multiple choice visual pattern problems of increasing difficulty. Each problem presents an incomplete pattern of geometric figures and requires selection of the missing piece from a set of multiple possible choices. The researchers then introduced a novel "lesion-deficit mapping" approach to disentangle the intricate anatomical patterns of common forms of brain injury, such as stroke.

Their approach treated the relations between brain regions as a mathematical network whose connections describe the tendency of regions to be affected together, either because of the disease process or in reflection of common cognitive ability. This enabled researchers to disentangle the brain map of cognitive abilities from the patterns of damage—allowing them to map the different parts of the brain and determine which patients did worse in the fluid intelligence task according to their injuries.

The researchers found that fluid intelligence impaired performance was largely confined to patients with right frontal lesions—rather than a wide set of regions distributed across the brain. Alongside brain tumours and stroke, such damage is often found in patients with a range of other neurological conditions, including traumatic brain injury and dementia.

These  findings indicate for the first time that the right frontal regions of the brain are critical to the high-level functions involved in fluid intelligence, such as problem solving and reasoning.

Lisa Cipolotti et al, Graph lesion-deficit mapping of fluid intelligence, Brain (2022). DOI: 10.1093/brain/awac304

Comment by Dr. Krishna Kumari Challa on December 28, 2022 at 12:56pm

Comment by Dr. Krishna Kumari Challa on December 28, 2022 at 12:49pm

About gut bacteria:

• Everyone has a unique composition of gut bacteria—shaped by genetics, environment, lifestyle and diet.
• The collection of gut bacteria, called the gut microbiota, is like an entire galaxy in our gut, with a staggering 100 billion of them per gram of stool.
• Gut bacteria in the colon serve to break down food parts that our body's digestive enzymes can't, e.g., dietary fiber.
• Humans can be divided into three groups based on the presence and abundance of three main groups of bacteria that most of us have: B-type (Bacteroides), R-type (Ruminococcaceae) and P-type (Prevotella).

Comment by Dr. Krishna Kumari Challa on December 28, 2022 at 12:48pm

Some guts are better than others at harvesting energy, study shows

New research from the University of Copenhagen suggests that a portion of the Danish population has a composition of gut microbes that, on average, extracts more energy from food than do the microbes in the guts of their fellow Danes. The research is a step towards understanding why some people gain more weight than others, even when they eat the same.

Unfair as it, some of us seem to put on weight just by looking at a plate of Christmas cookies, while others can munch away with abandon and not gain a gram. Part of the explanation could be related to the composition of our gut microbes. This is according to new research conducted at the University of Copenhagen's Department of Nutrition, Exercise and Sports.

The research is published in the journal Microbiome.

Researchers studied the residual energy in the feces of 85 Danes to estimate how effective their gut microbes are at extracting energy from food. At the same time, they mapped the composition of gut microbes for each participant.

The results show that roughly 40% of the participants belong to a group that, on average, extracts more energy from food compared to the other 60%. The researchers also observed that those who extracted the most energy from food also weighed 10% more on average, amounting to an extra nine kilograms.

The results indicate that being overweight might not just be related to how healthily one eats or the amount of exercise one gets. It may also have something to do with the composition of a person's gut microbes.

Following the study, the researchers suspect that a portion of the population may be disadvantaged by having gut bacteria that are a bit too effective at extracting energy. This effectiveness may result in more calories being available for the human host from the same amount of food.

Jos Boekhorst et al, Stool energy density is positively correlated to intestinal transit time and related to microbial enterotypes, Microbiome (2022). DOI: 10.1186/s40168-022-01418-5

Comment by Dr. Krishna Kumari Challa on December 28, 2022 at 12:38pm

Spontaneous baby movements are important for development of coordinated sensorimotor system

Comment by Dr. Krishna Kumari Challa on December 28, 2022 at 12:28pm

New bacterial therapy approach to treat lung cancer

Lung cancer is one of the deadliest cancers  around the world. Many of the currently available therapies have been ineffective, leaving patients with very few options. A promising new strategy to treat cancer has been bacterial therapy, but while this treatment modality has quickly progressed from labouratory experiments to clinical trials in the last five years, the most effective treatment for certain types of cancers may be in combination with other drugs.

Researchers report that they have developed a preclinical evaluation pipeline for characterization of bacterial therapies in lung cancer models. Their new study, published December 13, 2022, by Scientific Reports, combines bacterial therapies with other modalities of treatment to improve treatment efficacy without any additional toxicity. This new approach was able to rapidly characterize bacterial therapies and successfully integrate them with current targeted therapies for lung cancer.

The team used RNA sequencing to discover how cancer cells were responding to bacteria at the cellular and molecular levels. They built a hypothesis on which molecular pathways of cancer cells were helping the cells to be resistant to the bacteria therapy. To test their hypothesis, the researchers blocked these pathways with current cancer drugs and showed that combining the drugs with bacterial toxins is more effective in eliminating lung cancer cells. They validated the combination of bacteria therapy with an AKT-inhibitor as an example in mouse models of lung cancer.

This new study describes an exciting drug development pipeline that has been previously unexplored in lung cancer—the use of toxins derived from bacteria.

The preclinical data presented in the manuscript provides a strong rationale for continued research in this area, thereby opening up the possibility of new treatment options for patients diagnosed with this lethal disease.

 Dhruba Deb et al, Design of combination therapy for engineered bacterial therapeutics in non-small cell lung cancer, Scientific Reports (2022). DOI: 10.1038/s41598-022-26105-1

Comment by Dr. Krishna Kumari Challa on December 28, 2022 at 12:12pm

Brown algae removes carbon dioxide from the air and stores it in slime

Brown algae take up large amounts of carbon dioxide from the air and release parts of the carbon contained therein back into the environment in mucous form. This mucus is hard to break down for other ocean inhabitants, thus the carbon is removed from the atmosphere for a long time, according to a new study.

Researchers reveal that the algal mucus called fucoidan is particularly responsible for this carbon removal and estimate that brown algae could thus remove up to 550 million tons of carbon dioxide from the air every year.

Algae take up carbon dioxide from the atmosphere and use the carbon to grow. They release up to a third of the carbon they absorb back into the seawater, for example in the form of sugary excretions. Depending on the structure of these excretions, they are either quickly used by other organisms or sink toward the seafloor.

Fucoidan made up about half of the excretions of the brown algae species the researchers studied, the so-called bladderwrack.

Fucoidan is a recalcitrant molecule. The fucoidan is so complex that it is very hard for other organisms to use it. No one seems to like it. As a result, the carbon from the fucoidan does not return to the atmosphere quickly. "This makes the brown algae particularly good helpers in removing carbon dioxide from the atmosphere in the long term—for hundreds to thousands of years.

Buck-Wiese, Hagen et al, Fucoid brown algae inject fucoidan carbon into the ocean, Proceedings of the National Academy of Sciences (2022). DOI: 10.1073/pnas.2210561119. doi.org/10.1073/pnas.2210561119

Comment by Dr. Krishna Kumari Challa on December 28, 2022 at 12:05pm

Using an ethylene carbonate solvent with a sodium iodide salt to create a new kind of refrigerator

A pair of researchers  used a commonly known, naturally occurring phenomenon to build a new kind of environmentally safe refrigerator.

In their paper published in the journal Science, they describe how expanding on the idea of using salt to melt road ice to design and build a new kind of refrigerator.

For many years, people around the world have used salt to melt road ice to make travel easier. Though technically, the salt does not melt the ice, its dark color attracts heat, allowing the ice below it to melt, which than allows the salt to mix with the water. And it does not refreeze because the salt dramatically lowers the freezing point of the water.

It was on this part of the process that the researchers focused. They noted that a similar process could result in cooling a material simply by mixing it with sodium iodide (NaI) salt due to the phase transition. The second material in this case was an ethylene carbonate (EC) solvent. They further noted that repeatedly cooling a material should also cool the environment in which it is contained. And to make that happen, all they had to do was remove the salt, and then add it again.

The researchers call their process "ionocaloric" refrigeration, and built such a refrigerator to prove that it was viable. They started with a box and then added a mixing device to mix their two ingredients and another device that performed electrodialysis to remove the salt. Then tested the resulting device to determine if it would keep the temperature inside the box at a steady cool temperature, and if so, if it was more or less efficient than other refrigeration devices.

Their testing showed that their refrigerator was able to maintain a cool temperature and that it was approximately as efficient as refrigerators now on the market. The big advantage of the approach is that it does not emit any hydrofluorocarbons or other pollutants. They acknowledge that it does have one drawback—it takes quite a while for the mixed solution to cool.

Drew Lilley et al, Ionocaloric refrigeration cycle, Science (2022). DOI: 10.1126/science.ade1696

Emmanuel Defay, Cool it, with a pinch of salt, Science (2022). DOI: 10.1126/science.adf5114

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