Comment

Comment by Dr. Krishna Kumari Challa on December 30, 2022 at 11:39am

Parental astigmatism may increase risk for child astigmatism

Parental astigmatism may confer an independent and dose-dependent association with child astigmatism, according to a study published online Dec. 21 in JAMA Network Open.

Researchers examined the association between parental astigmatism (an optical system with astigmatism is one where rays that propagate in two perpendicular planes have different foci. If an optical system with astigmatism is used to form an image of a cross, the vertical and horizontal lines will be in sharp focus at two different distances) and child astigmatism. The analysis included 5,708 familial trios, each comprising a child aged 6 to 8 years and both parents, participating in the Hong Kong Children Eye Study.

The researchers found that astigmatism of ≥1.0 D in both parents was associated with greater odds of refractive astigmatism (RA; odds ratio, 1.62) and corneal astigmatism (CA; odds ratio, 1.94) in the child. When both parents had astigmatism ≥2.0 D, the risk increased further (odds ratios, 3.10 and 4.31, respectively), with higher parental astigmatism conferring higher risks for both RA and CA in children. There was a significant association between each parental astigmatism and corresponding child astigmatism (odds ratios, 0.76, 0.82, 1.70, and 1.33 for maternal RA, paternal RA, maternal CA, and paternal CA, respectively).

"The findings of this cross-sectional study suggest that parental astigmatism may confer an independent and dose-dependent association with child astigmatism," the authors write. "Children with parents with astigmatism should have early eye examinations for timely detection of astigmatism to facilitate age-appropriate vision correction and visual development."

More information: Ka Wai Kam et al, Association of Maternal and Paternal Astigmatism With Child Astigmatism in the Hong Kong Children Eye Study, JAMA Network Open (2022). DOI: 10.1001/jamanetworkopen.2022.47795

Comment by Dr. Krishna Kumari Challa on December 30, 2022 at 11:36am

Gastroesophageal reflux disease raises risk for periodontitis: Study

Patients with gastroesophageal reflux disease (GERD) have an increased risk for periodontitis development, according to a study published online Nov. 19 in Biomedicines.

Researchers conducted a retrospective cohort study to examine the association between GERD and subsequent periodontitis risk using epidemiological data from the Taiwan National Health Insurance Research Database from 2008 to 2018. A total of 20,125 participants with a minimum age of 40 years were included in the GERD group and propensity-matched in a 1:1 ratio with non-GERD participants.

The researchers found that the incidence rate of periodontitis was significantly higher in patients with versus those without GERD (30.0 versus 21.7 per 1,000 person-years; adjusted hazard ratio, 1.36). Patients with GERD had a higher risk for periodontitis in analyses stratified for age (adjusted hazard ratios, 1.31 and 1.42 for age 40 to 54 and 55 to 69 years, respectively), sex (adjusted hazard ratios, 1.40 and 1.33 for men and women, respectively), and presence and absence of comorbidity (adjusted hazard ratios, 1.36 and 1.40, respectively) compared with those without GERD. The risk for periodontitis was increased with an increasing number of emergency room visits among the GERD cohort (one or more versus less than one; adjusted hazard ratio, 5.19).

"Clinicians should pay more attention to the development of periodontitis while caring for patients with GERD," the authors write. "On the other hand, dentists may consider GERD as an etiology of unexplained periodontitis."

More information: Xin Li et al, Risk of Periodontitis in Patients with Gastroesophageal Reflux Disease: A Nationwide Retrospective Cohort Study, Biomedicines (2022). DOI: 10.3390/biomedicines10112980

Comment by Dr. Krishna Kumari Challa on December 30, 2022 at 11:16am

South Asian black carbon causes glacier loss on Tibetan Plateau

Black carbon aerosol is the product of incomplete combustion of fossil fuels and biomass, and has strong light absorption. Black carbon deposition in snow ice reduces the albedo of the snow ice surface, accelerating the melting of glaciers and snow cover, and thus changing the hydrological process and water resources in the region.

The South Asia region adjacent to the Tibetan Plateau is one of the regions with high black carbon emission in the world. Black carbon aerosol from South Asia can transport across the Himalayan Mountains to the inland region of the Tibetan Plateau.

Recently, a  research team analyzed the influence of black carbon aerosols on regional precipitation and glaciers over the Qinghai-Tibet Plateau.

Their findings were published in Nature Communications on Nov. 30.

The researchers found that since the 21st century, the South Asian black carbon aerosols have indirectly affected the material supply of the Tibetan Plateau glaciers by changing water vapour transport in the South Asian monsoon.

Black carbon aerosols in South Asia heat up the middle and upper atmosphere, thus increasing the north-south temperature gradient.

Accordingly, the convective activity in South Asia is enhanced, which causes convergence of water vapor in South Asia. Meanwhile, black carbon also increases the number of cloud condensation nuclei in the atmosphere."

These changes in meteorological conditions caused by black carbon aerosols make more water vapor form precipitation in South Asia, and less water vapor transmit to the Tibetan Plateau. As a result, precipitation in the central and southern Tibetan Plateau decreases during monsoon, especially in the southern part of the Tibetan Plateau.

The decrease of precipitation further leads to the decrease of material supply of glaciers. From 2007 to 2016, the reduced material supply accounted for 11.0% of the average glacier material loss on the Tibetan Plateau and 22.1% in the southern part of the plateau.

"The transboundary transport and deposition of black carbon aerosols in South Asia accelerate glacier ablation on the Tibetan Plateau. Meanwhile, the reduction of plateau summer precipitation will reduce the material supply of plateau glacier, which will increase the amount of glacier material deficit.

Junhua Yang et al, South Asian black carbon is threatening the water sustainability of the Asian Water Tower, Nature Communications (2022). DOI: 10.1038/s41467-022-35128-1

**

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

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