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Comment by Dr. Krishna Kumari Challa on May 24, 2024 at 10:02am

Why the brain can robustly recognize images, even without colour

Even though the human visual system has sophisticated machinery for processing colour, the brain has no problem recognizing objects in black-and-white images. A new study offers a possible explanation for how the brain comes to be so adept at identifying both colour and colour-degraded images.

Using experimental data and computational modeling, the researchers found evidence suggesting the roots of this ability may lie in development. The work has been published in Science

Early in life, when newborns receive strongly limited colour information, the brain is forced to learn to distinguish objects based on their luminance, or intensity of light they emit, rather than their colour. Later in life, when the retina and cortex are better equipped to process colours, the brain incorporates colour information as well but also maintains its previously acquired ability to recognize images without critical reliance on colour cues.

The findings also help to explain why children who are born blind but have their vision restored later in life, through the removal of congenital cataracts, have much more difficulty identifying objects presented in black and white. Those children, who receive rich colour input as soon as their sight is restored, may develop an overreliance on colour that makes them much less resilient to changes or removal of colour information.

Researchers  have observed that limitations in early sensory input can also benefit other aspects of vision, as well as the auditory system.

In 2022, they used computational models to show that early exposure to only low-frequency sounds, similar to those that babies hear in the womb, improves performance on auditory tasks that require analyzing sounds over a longer period of time, such as recognizing emotions. 

Marin Vogelsang et al, Impact of early visual experience on later usage of color cues, Science (2024). DOI: 10.1126/science.adk9587. www.science.org/doi/10.1126/science.adk9587

Comment by Dr. Krishna Kumari Challa on May 24, 2024 at 9:22am

Exposure to endocrine-disrupting chemicals in utero associated with higher odds of metabolic syndrome in children

The term 'metabolic syndrome' (MetS) encompasses a group of factors, such as abdominal obesity, hypertension and insulin resistance, that together increase the risk of cardiovascular disease and type 2 diabetes.

A new study suggests that prenatal exposure to a combination of endocrine disrupting chemicals (EDCs) is associated with poorer metabolic health in childhood, which in turn may contribute to an increased risk of metabolic syndrome in adulthood.

EDCs are chemical substances that are so named because of their ability to interfere with the functioning of our hormonal system, growth, energy balance and metabolism and whose exposure, given their ubiquity in our environment, is difficult to escape.

Previous studies have already shown a link between individual exposure to some of these compounds during the prenatal phase and some of the factors that make up the metabolic syndrome, particularly obesity and blood pressure.

The study involved 1,134 mothers and their children from six European countries (Spain, France, Greece, Lithuania, Norway and the United Kingdom), all volunteers from the HELIX (Human Early Life Exposome) cohort. Prenatal exposure to a total of 45 endocrine disruptors was analyzed through blood and urine samples collected from the mothers during pregnancy or from the umbilical cord after birth.

Later, when the children were between 6 and 11 years old, they were followed up, including a clinical examination, interview and collection of biological samples. This yielded data on waist circumference, blood pressure, cholesterol, triglycerides and insulin levels, which were aggregated to obtain a risk index for metabolic syndrome.

Statistical analysis showed that mixtures of metals, perfluoroalkylated and polyfluoroalkylated substances (PFAS), organochlorine pesticides and flame retardants (or PBDEs) were associated with a higher risk of metabolic syndrome. In the case of metals, the association observed was mainly due to the effect of mercury, the main source of which is the intake of large fish.

PFASs are one of the most widely used families of chemical compounds, being used in pesticides, paints, non-stick pans or fast food packaging, among many other common uses. Because of their persistence, they are also known as the "forever chemicals." Also very persistent are organochlorine pesticides, which were already banned in Europe in the 1970s, but to which we are still widely exposed due to their permanence in the environment.

Researchers also observed that associations were stronger in girls for mixtures of PFASs and polychlorinated biphenyls (PCBs), while boys were more susceptible to exposure to parabens. Since endocrine disruptors interfere with sex steroid hormones, these differences fall within what would be expected.

These results suggest that exposure to widespread mixtures of endocrine disruptors during pregnancy may be associated with adverse metabolic health in both boys and girls. This association may contribute to the current increase in the prevalence of lifetime metabolic syndrome, which currently affects a quarter of the adult population, with upward trends evident even among young people
 Prenatal Exposure to Chemical Mixtures and Metabolic Syndrome Risk in Children, JAMA Network Open (2024). DOI: 10.1001/jamanetworkopen.2024.12040

Comment by Dr. Krishna Kumari Challa on May 23, 2024 at 9:41am

Newborns whose mother spoke in a mix of languages during pregnancy are more sensitive to a range of sound pitches

It's well established that babies in the womb hear and learn about speech, at least in the third trimester. For example, newborns have been shown to already prefer the voice of their mother, recognize a story that had been repeatedly told to them while in the womb, and tell apart their mother's native language.

What wasn't known until now was how developing fetuses learn about speech when their mother speaks to them in a mix of languages. Yet this is common: there are 3.3 billion bilingual people (43% of the population) worldwide, and in many countries, bilingualism or multilingualism is the norm.

Researchers showed that exposure to monolingual or a bilingual speech has different effects at birth on 'neural encoding' of voice pitch and vowel sounds: that is, how information about these aspects of speech has been initially learned by the fetus.

At birth, newborns from bilingual mothers appear more sensitive to a wider range of acoustic variation of speech, whereas newborns from monolingual mothers seem to be more selectively tuned to the single language they have been immersed in.

Exposure to bilingual or monolingual maternal speech during pregnancy affects the neurophysiological encoding of speech sounds in neonates differently, Frontiers in Human Neuroscience (2024). DOI: 10.3389/fnhum.2024.1379660

Comment by Dr. Krishna Kumari Challa on May 22, 2024 at 10:29am

Nightmares could be an early warning sign of an autoimmune disease flare-up – new study

Nightmares coming before autoimmune diseases have been found in other neurological diseases. Descriptions of flare-related nightmares in our study often involved being attacked, trapped, crushed or falling. Many were very distressing. One person described them as: “Horrific, like murders, like skin coming off people, horrific.” Another important finding was that these nightmares often came before a disease flare-up, particularly in people who then had hallucinations as part of their disease pattern. This was more likely in people with lupus than the other rheumatological diseases such as inflammatory arthritis. This wasn’t unexpected as lupus is known to affect the brain in some cases. Of the patients also reporting hallucinations, 61% of lupus patients and 34% with other autoimmune rheumatological diseases reported increasing disrupted sleep (mostly nightmares) just before their hallucinations.

https://theconversation.com/nightmares-could-be-an-early-warning-si...

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Comment by Dr. Krishna Kumari Challa on May 22, 2024 at 9:20am

Body lice may be bigger plague spreaders than previously thought

A new laboratory study suggests that human body lice are more efficient at transmitting Yersinia pestis, the bacterium that causes plague, than previously thought, supporting the possibility that they may have contributed to past pandemics.

Y. pestis has been the culprit behind numerous pandemics, including the Black Death of the Middle Ages that killed millions of people in Europe. It naturally cycles between rodents and fleas, and fleas sometimes infect humans through bites; thus, fleas and rats are thought to be the primary drivers of plague pandemics.
Body lice—which feed on human blood—can also carry Y. pestis, but are widely considered to be too inefficient at spreading it to contribute substantially to outbreaks. However, the few studies that have addressed lice transmission efficiency have disagreed considerably.

To help clarify the potential role of body lice in plague transmission, Bland and colleagues conducted a series of laboratory experiments in which body lice fed on blood samples containing Y. pestis. These experiments involved the use of membrane feeders, which simulate warm human skin, enabling scientists to study transmission potential in a laboratory setting.

They found that the body lice became infected with Y. pestis and were capable of routinely transmitting it after feeding on blood containing levels of the pathogen similar to those found in actual human plague cases.

They also found that Y. pestis can infect a pair of salivary glands found in body lice known as the Pawlowsky glands, and lice with infected Pawlowsky glands transmitted the pathogen more consistently than lice whose infection was limited to their digestive tract. It is thought that Pawlowsky glands secrete lubricant onto the lice's mouthparts, leading the researchers to hypothesize that, in infected lice, such secretions may contaminate mouthparts with Y. pestis, which may then spread to humans when bitten. These findings suggest that body lice may be more efficient spreaders of Y. pestis than previously thought, and they could have played a role in past plague outbreaks.

 Bland DM, Long D, Rosenke R, Hinnebusch BJ (2024) Yersinia pestis can infect the Pawlowsky glands of human body lice and be transmitted by louse bite. PLoS Biology (2024). DOI: 10.1371/journal.pbio.3002625

Comment by Dr. Krishna Kumari Challa on May 22, 2024 at 9:16am

Male and female mice exhibit different empathic behaviors to others' pain

Social interactions are multi-faceted experiences that entail understanding the emotional states of others and responding appropriately. Neuroscientists and psychologists have been studying social interactions for decades, in the hope of understanding their neural and behavioral underpinnings.

A team of researchers  recently carried out a study exploring how male and female mice respond to the pain of other mice. Their findings, published in Neuron, suggest that there are both neurobiological and behavioural differences between the two sexes, specifically in relation to their empathic responses.

Recognizing the affective states of social counterparts and responding appropriately fosters successful social interactions.

The primary objective of the recent study was to delve deeper into how male and female mammals respond to another animal in pain, both in terms of their behavior and brain activity. To do this, they carried out a series of experiments on mice, where two mice were placed in lateral chambers, while an observing mouse was placed in the central section of a common cage.

One of the mice in the lateral chamber was given an injection that caused abdominal pain, while the other two were not administered anything. The researchers monitored the behavior of the mouse in the central part of the cage, who could explore the environment freely and thus whether to interact with the other mice and in what ways.
Initially, both male and female mice moved in their surroundings, displaying similar exploratory behaviors. Yet after a while, particularly towards the end of each experimental trial, the team found that male mice exhibited more grooming behaviors, while female mice demonstrated a social preference for the mouse that was in pain, as they spent more time in its proximity and sniffing it.
"We show that male and female mice emit distinct olfactory cues after experiencing distress," the researchers wrote. "These cues activate distinct neural circuits in the piriform cortex (PiC) and evoke sexually dimorphic empathic behaviours on observers.
Specifically, the PiC → PrL pathway is activated in female observers, inducing a social preference for the distressed counterpart. Conversely, the PiC → MeA pathway is activated in male observers, evoking excessive self-grooming behaviors."
This distinct neural pathway that the researchers found to be activated in male observers originated from non-overlapping PiC neuron populations with different gene expression signatures. Notably, these gene expression signatures are regulated by transcription factors and sex hormones.
Overall, their observations suggest that male and female mice are biologically inclined to respond differently to other mice in pain. While females are more likely to get closer to a peer who is in pain, males tend to respond to another's pain with excessive self-grooming.
The results of this study could soon be explored further and validated in additional experiments. In the future, they could pave the way for the discovery of new neural processes underpinning sex-specific social behaviours.

Shunchang Fang et al, Sexually dimorphic control of affective state processing and empathic behaviors, Neuron (2024). DOI: 10.1016/j.neuron.2024.02.001

Comment by Dr. Krishna Kumari Challa on May 21, 2024 at 2:11pm

Scientists Confirm Microplastics Now Detected in Human Testicles

We can now add testicles to the list of places where microplastics have managed to spread – alongside human placentas, ancient rocks, clogged arteries, blue whales, baby poop, the wilderness of Antarctica, near the peak of Mount Everest, and the bottom of the ocean.

Research led by the University of New Mexico looked at testicular tissue taken from both dogs and humans, finding microplastics in every sample, with an abundance almost three times higher in humans than in dogs.
The team found an average 122.63 micrograms of microplastics per gram of tissue in canines, and 329.44 micrograms per gram in people.

Besides giving us another sobering reminder of how plastic pollution is penetrating every part of our bodies, the study raises some concerning questions in regards to how these microscopic fragments might impact male fertility.

https://academic.oup.com/toxsci/advance-article-abstract/doi/10.109...

Comment by Dr. Krishna Kumari Challa on May 21, 2024 at 12:39pm

Now Cancer drug pollution is a cause for concern!

As incidence of cancer increases globally, the use of cancer drugs is also growing at a rate of approximately 10 percent per year in developed countries.
Pharmaceuticals significantly contribute to the improvement of human health; however, their environmental impacts have also become a major concern.

Cancer drugs in our ecosystems
Among the many molecules used to treat cancers are cytostatics.

As defined by the United States' National Institutes of Health (NIH), a cystostatic is "a substance that slows or stops the growth of cells, including cancer cells, without killing them."

When a cancer patient takes these drugs, the chemicals in them, including cytostatics, are eventually evacuated through the patients' solid and liquid waste.

A patients' waste ends up in the hospital or domestic wastewater system, where the chemicals in it are not entirely eliminated by end of pipe wastewater treatment plants. These chemicals can then find their way into aquatic ecosystems, and even our drinking water supply, at varying concentrations.

Cytostatic drugs are now classified as contaminants of emerging concern (CECs) due to their hazardous environmental impact.

The message is clear: this problem is only going to get worse as more people use cancer drugs.
The continuous release of pharmaceuticals into aquatic ecosystems (even at low levels) can reduce surface water quality, endanger biodiversity and disrupt ecosystem functioning.
They have a toxic impact on aquatic flora and fauna, especially the fish.

https://www.sciencedirect.com/science/article/abs/pii/S004896972205...

Comment by Dr. Krishna Kumari Challa on May 21, 2024 at 12:33pm

 Rusting Rivers: The Alarming Impact of Permafrost Thaw on Arctic Rivers

In this video, researchers reveal the startling discovery of over 75 streams and rivers in Alaska's Brooks Range turning orange due to metals released in permafrost thaw. Researchers delve into the consequences of this phenomenon, its impact on aquatic ecosystems and local communities, and the ongoing research efforts to understand and mitigate these changes.

Comment by Dr. Krishna Kumari Challa on May 21, 2024 at 11:04am

The study's results indicate that the group that received the supplements was much more inclined to reject unequal offers at the end of the seven weeks, even when the money split was slightly unbalanced. Conversely, the placebo group behaved similarly during the first and second test sessions.
Moreover, the behavioral change in the supplemented group was accompanied by biological changes: the participants who, at the start of the study, had the greatest imbalance between the two types of bacteria that dominate the gut flora (Firmicutes and Bacteroidetes) experienced the most significant change in the composition of their gut microbiota with the intake of supplements. In addition, they also showed the greatest sensitivity to fairness during the tests.
The researchers also observed a sharp drop in their levels of tyrosine, a dopamine precursor, after the seven-week intervention. For the first time, a causal mechanism is emerging: the composition of the gut microbiota could influence social behavior through the precursors of dopamine, a neurotransmitter involved in brain reward mechanisms.

"It's too early to say that gut bacteria can make us less rational and more receptive to social considerations," conclude the researchers.
However, these new results clarify which biological pathways we must look at. The prospect of modulating the gut microbiota through diet to positively influence decision-making is fascinating. We need to explore this avenue very carefully.

Marie Falkenstein et al, Impact of the gut microbiome composition on social decision-making, PNAS Nexus (2024). DOI: 10.1093/pnasnexus/pgae166

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