Comment

Comment by Dr. Krishna Kumari Challa on Thursday

The search for life on Mars feels like looking for a needle in a haystack. But it could be narrowed down and made easier by having well-defined targets that, more than others, could be possible homes for life.

Therefore, the scientists behind this latest study think the eight possible karstic caves should be high-priority targets for future human or robotic missions to the planet. Even if no life is there, they could serve as landing sites and natural shelters for astronauts when they are not exploring the surface.

 Ravi Sharma et al, Water-driven Accessible Potential Karstic Caves in Hebrus Valles, Mars: Implications for Subsurface Habitability, The Astrophysical Journal Letters (2025). DOI: 10.3847/2041-8213/ae0f1c

Part 2

Comment by Dr. Krishna Kumari Challa on Thursday

Scientists discover caves carved by water on Mars that may have once harbored life

If there is, or ever has been, life on Mars, the chances are it would exist in caves protected from the severe dust storms, extreme temperatures, and high radiation present on its surface. One place to focus our attention could be eight possible cave sites (called skylights) recently discovered by researchers.

In a paper published in The Astrophysical Journal Letters, the team presents the first evidence of a new type of cave on the red planet, formed by water dissolving rock. Most Martian caves discovered so far have been lava tubes, but the study authors argue that they have identified the first documented karstic caves on Mars.

"These skylights are interpreted as the first known potential karstic caves on Mars, representing collapse entrances formed through the dissolution of water-soluble lithologies—defining a new cave-forming class distinct from all previously reported volcanic and tectonic skylights," wrote the researchers in their paper.

On Earth, karstic caves are typically formed when water dissolves soluble rock such as limestone or gypsum, creating and enlarging underground cracks and fractures that grow large enough to become caves. The paper proposes a similar process on Mars, where ancient Martian water may have dissolved carbonate- and sulfate-rich rocks on the crust.

The caves are located in the Hebrus Valles, a northwestern region, and are eight pits that were mapped by previous Mars missions. They are deep and predominantly circular depressions, not impact craters, which typically have raised rims and ejected debris around them.

The researchers studied data from the Thermal Emission Spectrometer (TES) that was onboard NASA's Mars Global Surveyor and discovered that the rocks around the pits are rich in carbonates and sulfates. These are the types of rocks that water can easily dissolve. The team also used high-resolution imagery to create 3D structural models of the pits, which showed that their shapes are consistent with collapse caused by water rather than volcanic or tectonic activity.

Comment by Dr. Krishna Kumari Challa on Thursday

Bees learn to read simple 'Morse code'

Researchers  have shown for the first time that an insect—the bumblebee Bombus terrestris—can decide where to forage for food based on different durations of visual cues. Their paper is published in the journal Biology Letters.

In Morse code, a short duration flash or "dot" denotes a letter "E" and a long duration flash, or "dash," means letter "T." Until now, the ability to discriminate between "dot" and "dash" has been seen only in humans and other vertebrates such as macaques or pigeons.

Now researchers  studied this ability in bees. They built a special maze to train individual bees to find a sugar reward at one of two flashing circles, shown with either a long or short flash duration. For instance, when the short flash, or "dot," was associated with sugar, then the long flash, or "dash," was instead associated with a bitter substance that bees dislike.

In each room in the maze, the position of the dot and dash stimulus was changed, so that bees could not rely on spatial cues to orient their choices. After bees learned to go straight to the flashing circle paired with the sugar, they were tested with flashing lights but no sugar present, to check whether bees' choices were driven by the flashing light, rather than by olfactory or visual cues present in the sugar.

It was clear the bees had learned to tell the light apart based on their duration, as most of them went straight to the 'correct' flashing light duration previously associated with sugar, irrespective of spatial location of the stimulus.

Since bees don't encounter flashing stimuli in their natural environment, it's remarkable that they could succeed at this task. The fact that they could track the duration of visual stimuli might suggest an extension of a time processing capacity that has evolved for different purposes, such as keeping track of movement in space or communication.

Alternatively, this surprising ability to encode and process time duration might be a fundamental component of the nervous system that is intrinsic in the properties of neurons. Only further research will be able to address this issue.

Many complex animal behaviors, such as navigation and communication, depend on time-processing abilities. It will be important to use a broad comparative approach across different species, including insects, to shed light on the evolution of those abilities. Processing durations in insects is evidence of a complex task solution using minimal neural substrate.

This has implications for complex cognitive-like traits in artificial neural networks, which should seek to be as efficient as possible to be scalable, taking inspiration from biological intelligence.

 Duration discrimination in the bumblebee Bombus terrestris, Biology Letters (2025). DOI: 10.1098/rsbl.2025.0440. royalsocietypublishing.org/doi … .1098/rsbl.2025.0440

Comment by Dr. Krishna Kumari Challa on Wednesday

Computers that run on human brain cells
At a company on the shores of Lake Geneva, clumps of living brain cells are waiting for your call. These blobs, about the size of a grain of sand, are available to research teams studying how brains work or exploring the possibility of making computers with brain-cell processors. These neural cells can receive electrical signals and respond to them — much as computers do. For some scientists, the dream is to build supercomputers that share the astonishing power efficiency of the human brain. What they’re not working on, they emphasize, is ‘brains in jars’: the blobs are not sentient or conscious (yet).

https://www.nature.com/articles/d41586-025-03633-0?utm_source=Live+...

Comment by Dr. Krishna Kumari Challa on Wednesday

Canada ( and entire Americas region) loses measles elimination status
Canada no longer holds measles elimination status after experiencing a cross-country outbreak that has persisted for more than 12 months. By default, this means that the entire Americas region has also lost its status. Infections took hold in undervaccinated Mennonite communities where the COVID-19 pandemic eroded already-shaky trust in the healthcare system — a shared source of recent measles outbreaks in the United States. The number of new cases is going down, but the loss is “a giant wake-up call that we have gaps in our public health infrastructure”, says physician-scientist Isaac Bogoch.

https://www.cbc.ca/news/health/livestory/canada-measles-elimination...

Comment by Dr. Krishna Kumari Challa on Wednesday

Being multilingual es bueno para el cerebro

Want a younger brain? Learn another language

A vast study suggests that being multilingual can slow down cognitive ageing.

The ability to speak more than one language might slow brain ageing and protect against cognitive decline. In a study of more than 80,000 people, researchers found that people who are multilingual are half as likely to show signs of accelerated biological ageing than are those who just speak one language. The effect was also larger in people that spoke more than one additional language. The researchers hope that their findings will influence policy makers to encourage language learning in education.

I learnt five languages. Can my brain stay forever young?

https://www.nature.com/articles/s43587-025-01000-2.epdf?sharing_tok...

https://www.nature.com/articles/d41586-025-03677-2?utm_source=Live+...

Comment by Dr. Krishna Kumari Challa on Wednesday

Did You Know? The "Big Four" are not the only dangerous snakes of India: While the four species are responsible for the most bites, India is home to over 350 snake species, nearly 60 of which are considered clinically relevant to humans.

https://researchmatters.in/news/age-not-sex-or-location-determines-....

Comment by Dr. Krishna Kumari Challa on Wednesday

Age, not sex or location, determines venom yield of India's 'Big Four' snakes, shows study

A new study by researchers from the Indian Institute of Science (IISc) has shown that the amount of venom produced by the big four snakes is overwhelmingly determined by the snake's life stage (age) rather than its sex or geographic location. The finding could have immediate implications for improving antivenom production and clinical treatment across the subcontinent.

To understand how much venom each snake delivers per bite, the researchers collected and quantified venom from the big four snakes across India's major bioclimatic zones. They collected venom samples from 338 wild-caught snakes during rescue operations coordinated with State Forest Departments and local snake rescuers across 10 states in India between 2021 and 2024. The venom was collected by experienced herpetologists using safe handling methods, encouraging the snake to bite onto a sterile parafilm stretched over a beaker. After extraction, all snakes were safely returned to their natural habitats. The collected crude venom was then freeze-dried (lyophilised) and its dry weight measured using a high-precision microbalance. This systematic, pan-Indian approach to sampling wild populations yielded a vast, diverse dataset.

The findings reveal substantial variation in venom output among the species, a pattern that largely correlates with the snake's overall body size. The two larger species, the Spectacled Cobra and the Russell's Viper, were the high-yield producers, meaning they delivered large quantities of venom with every bite. They averaged 136.10 mg and 106.60 mg of dry venom, respectively. In stark contrast, the smaller Common Krait (Bungarus caeruleus) and the Saw-scaled Viper (Echis carinatus) produced significantly less, with average yields of only 8.95 mg and 2.76 mg.

The most significant factor influencing this yield, however, was the snake's developmental stage. The study found statistically significant differences in venom yield across life stages for the cobra, Russell's viper, and saw-scaled viper. For example, adult Spectacled Cobras had a median venom yield of 125.00 mg, which is nearly three times the 47.60 mg median yield of subadults and almost twenty times the 6.50 mg median yield of juveniles. Similar trends were observed in Russell's Viper, with adults producing the highest median yield (95.69 mg) compared to juveniles (3.00 mg). This pattern strongly suggests that as a snake grows and matures, its capacity to produce and deliver venom increases dramatically.

Interestingly, the researchers found that sex-based differences were statistically insignificant across all four species.

Hiss and tell: What influences venom yields of India’s big four snakes?

https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd....

Comment by Dr. Krishna Kumari Challa on Wednesday

The team also examined whether the brain's capacity for long-term potentiation (LTP), a cellular basis of learning and memory, changes with time of day. This represents the brain's potential for metaplasticity (the brain's ability to adjust how easily its networks change). Remarkably, repetitive optical stimulation induced LTP-like enhancement at sunrise, but not at sunset.

This was unexpected, as it suggests that although sleep pressure and fatigue peak at sunrise, the brain's metaplastic potential is heightened at this time. These findings indicate that the brain's ability to reorganize itself follows a daily rhythm, with specific periods more favorable for learning and adaptation.

These results imply that our brains have temporal windows that favor adaptability.
Knowing when the brain is most receptive to changing could help optimize training, rehabilitation, and stimulation-based therapies.
In humans, who are mainly active during daylight hours, the capacity for learning and memory formation may peak during the twilight period approaching sunset. In other words, the best time to study or learn something new may be before bedtime.

The study reveals how daily rhythms fine-tune the balance between excitability and plasticity in the cortex. Because adenosine levels and sleep pressure follow circadian patterns, this mechanism may synchronize brain adaptability with behavioral cycles such as rest and activity. The research provides new insight into how the brain coordinates energy use, neural signaling, and learning capacity across the day.

Yuki Donen et al, Diurnal modulation of optogenetically evoked neural signals, Neuroscience Research (2025). DOI: 10.1016/j.neures.2025.104981

Part 2

Comment by Dr. Krishna Kumari Challa on Wednesday

The flexible brain: How circuit excitability and plasticity shift across the day

Our brains do not react in a fixed, mechanical way like electronic circuits. Even if we see the same scene every day on our commute to work, what we feel—and whether it leaves a lasting impression—depends on our internal state at that moment. For example, your commute may be a blur if you're too tired to pay attention to your surroundings.

The 24-hour cycle that humans naturally follow is one of the factors that shapes the brain's internal environment. These internal physiological cycles arise from the interplay between the body's intrinsic circadian clock and the external light-dark cycle that synchronizes it. Yet how such daily fluctuations influence brain chemistry and affect neuronal excitability and plasticity has remained largely unknown.

Now, researchers  have directly observed time-of-day-dependent changes in neural signal responses in the brains of nocturnal rats. Their findings are published in Neuroscience Research.

Using optogenetics, the team activated neurons in the visual cortexes of rats and recorded the resulting electrical activity. This approach allowed precise quantification of neural responsiveness. They found that identical neural stimuli evoked different responses depending on the time of day. Neural activity was reduced at sunrise and enhanced at sunset. Since rats are nocturnal, sunrise represents the period after a night of activity when they are preparing to sleep.

To explore the underlying mechanism explaining why this was occurring, the researchers looked at adenosine, a neuromodulator that accumulates during wakefulness and makes us feel sleepy.

When the researchers blocked the action of adenosine, neural activity at sunrise became disinhibited and enhanced, showing that adenosine helps regulate cortical excitability across the day.

So neural excitability is not constant; it depends on the brain's internal state. 

The results show that even identical neurons can respond differently depending on the time of day, governed by molecules like adenosine that link metabolism, sleep, and neuronal signaling.

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