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Comment by Dr. Krishna Kumari Challa on August 20, 2025 at 12:08pm

Imagination won't take you everywhere—study reveals limitations of the mind's eye

Our imagination might not be as powerful as we think when it comes to holding visual images, according to a first-of-its-kind study by psychologists.

 The research found that people can remember more items when they've seen them, compared to when they must imagine them.

While short-term visual memory can hold three to four items at once, our imagination can manage only two items before becoming less accurate.

Across a series of five experiments, more than 150 participants were asked to either remember or imagine the locations of objects on a grid.

Researchers examined how accurately participants could detect changes in specific locations under various conditions, including timing, cueing, display type, and object complexity. They then compared the number of items participants could correctly remember after viewing them with the number they could accurately imagine and recall without having seen them.

Findings showed that even when given more time or simpler images, people still imagined fewer items than they could remember visually.

The study, "The relation between the capacities of imagination and visual memory in the short-term," published in the Journal of Experimental Psychology: Human Perception and Performance, offers the first direct comparison of how much information people can hold in visual imagination versus visual memory.

Imagination and memory use similar parts of the brain, but this is the first time scientists have measured exactly how they differ when it comes to capacity. These findings demonstrate that actually seeing something, even a brief glimpse, gives our brain extra sensory support that bolsters our memory. In fact, researchers estimate that 17–35% of visual memory capacity depends on sensory input. When we imagine something from scratch, we don't have that input from our eyes, so it's harder to hold detailed images.

We use imagination constantly in everyday life, as imagery is seen as essential for navigating and predicting our environment and is involved in decision-making and emotion regulation, but the study reveals that our capacity to visualize is surprisingly limited, and this might affect how we make decisions, remember plans, or follow instructions when we rely on mental imagery alone.

Christopher Atkin et al, The relation between the capacities of imagination and visual memory in the short term., Journal of Experimental Psychology: Human Perception and Performance (2025). DOI: 10.1037/xhp0001364

Comment by Dr. Krishna Kumari Challa on August 20, 2025 at 11:37am

Hight-salt diet sparks brain inflammation that could explain stubborn high blood pressure

A new study finds that a high-salt diet triggers brain inflammation that drives up blood pressure. 

The research suggests the brain may be a missing link in certain forms of high blood pressure—or hypertension—traditionally attributed to the kidneys.

This is new evidence that high blood pressure can originate in the brain, opening the door for developing treatments that act on the brain.

Hypertension affects two-thirds of people over 60 and contributes to 10 million deaths worldwide each year. Often symptomless, the condition increases the risk of heart disease, stroke and other serious health problems.

About one-third of patients don't respond to standard medications, which primarily target the blood vessels and kidneys based on the long-standing view that hypertension begins there.

The study, published in the journal Neuron, suggests the brain may also be a key driver of the condition, particularly in treatment-resistant cases.

How salt disrupts the brain

To mimic human eating patterns, rats were given water containing 2% salt, comparable to a daily diet high in fast food and items like bacon, instant noodles and processed cheese.

The high-salt diet activated immune cells in a specific brain region, causing inflammation and a surge in the hormone vasopressin, which raises blood pressure. Researchers tracked these changes using cutting-edge brain imaging and lab techniques that only recently became available.

The brain's role in hypertension has largely been overlooked, in part because it's harder to study.

The researchers used rats instead of the more commonly studied mice because rats regulate salt and water more like humans. That makes the findings more likely to apply to people.

Next, the scientists plan to study whether similar processes are involved in other forms of hypertension.

Ning Gu et al, Microglia regulate neuronal activity via structural remodeling of astrocytes, Neuron (2025). DOI: 10.1016/j.neuron.2025.07.024

Comment by Dr. Krishna Kumari Challa on August 20, 2025 at 11:31am

To examine the mechanisms behind the link between cardiovascular disease and cancer growth, the study authors developed a mouse model with breast tumors and induced temporary ischemia in one hind limb. The team then compared cancer growth in mice with and without impaired blood flow.

Their findings build on the nature of the immune system, which evolved to attack invading bacteria and viruses, and, under normal conditions, to detect and eliminate cancer cells. These protective functions rely on stem cell reserves in the bone marrow, which can be activated as needed to produce key white blood cell populations throughout life.

Normally, the immune system responds to injury or infection by ramping up inflammation to eliminate threats, then scaling back to avoid harm to healthy tissue. This balance is maintained by a mix of immune cells that either activate or suppress inflammation.

The researchers found that reduced blood flow disrupts this equilibrium. It reprograms stem cells in the bone marrow to favor the production of "myeloid" immune cells (monocytes, macrophages, neutrophils) that dampen immune responses, while reducing output of lymphocytes like T cells that help to mount strong anti-tumor responses.

The local environment within tumors showed a similar shift, accumulating more immune-suppressive cells– including Ly6Chi monocytes, M2-like F4/80+ MHCIIlo macrophages, and regulatory T cells—that shield cancer from immune attack.

Further experiments showed that these immune changes were long-lasting. Ischemia not only altered the expression of hundreds of genes, shifting immune cells into a more cancer-tolerant state, but also reorganized the structure of chromatin–the protein scaffolding that controls access to DNA–making it harder for immune cells to activate genes involved in fighting cancer.
results reveal a direct mechanism by which ischemia drives cancer growth, reprogramming stem cells in ways that resemble aging and promote immune tolerance.
These findings open the door to new strategies in cancer prevention and treatment, like earlier cancer screening for patients with peripheral artery disease and using inflammation-modulating therapies to counter these effects."

Moving forward, the research team hopes to help design clinical studies that evaluate whether existing inflammation-targeted therapies can counter post-ischemic changes driving tumor growth.

Ischemic Injury Drives Nascent Tumor Growth via Accelerated Hematopoietic Aging, JACC CardioOncology (2025). DOI: 10.1016/j.jaccao.2025.05.016

Part 2

Comment by Dr. Krishna Kumari Challa on August 20, 2025 at 11:30am

Restricted blood flow speeds tumor growth by aging the immune system, study finds

Cutting off blood flow can prematurely age the bone marrow, weakening the immune system's ability to fight cancer, according to a new study .

Published online in JACC-CardioOncology, the study showed that peripheral ischemia–restricted blood flow in the arteries in the legs–caused breast tumors in mice to grow at double the rate seen in mice without restricted flow. These findings build on a 2020 study by the same team that found ischemia during a heart attack to have the same effect.

Ischemia occurs when fatty deposits, such as cholesterol, accumulate in artery walls, leading to inflammation and clotting that restrict the flow of oxygen-rich blood. When this happens in the legs, it causes peripheral artery disease, which affects millions of people, and can increase the risk of heart attack or stroke.

This new study  shows that impaired blood flow drives cancer growth regardless of where it happens in the body.

This link between peripheral artery disease and breast cancer growth underscores the critical importance of addressing metabolic and vascular risk factors as part of a comprehensive cancer treatment strategy.

Importantly, the research team found that restricted blood flow triggers a shift toward immune cell populations that cannot efficiently fight infections and cancer, mirroring changes seen with aging.

Part 1

Comment by Dr. Krishna Kumari Challa on August 20, 2025 at 8:56am

How HPV reprograms immune cells to help cancer grow

The most common cancer-causing strain of human papillomavirus (HPV), HPV16, undermines the body's defenses by reprogramming immune cells surrounding the tumor, according to new research.

In mice, blocking this process boosted the ability of experimental treatments for HPV to eliminate cancer cells. The results were published in the Journal for ImmunoTherapy of Cancer.

HPV16 causes more than half of cervical cancer cases and roughly 90% of HPV-linked throat cancers. It can be neutralized with the preventive vaccine Gardasil-9, but only if vaccination occurs prior to HPV exposure.

Researchers are now working to develop "therapeutic vaccines," which can be taken after HPV exposure—for instance, following an abnormal pap smear or cancer diagnosis—to trigger an immune response against infected cells by T-cells, a type of "fighter" cell that helps defend the body from disease. But these vaccines, now in clinical trials, have limited effectiveness—and the new study helps explain why.

The research focuses on a signalling protein in the immune system with inflammatory properties called Interleukin-23 or IL-23. While IL-23 was previously implicated in cervical and throat cancers, its exact role was unclear.

In a series of tests in mice and cell cultures,  researchers found that two HPV proteins, E6 and E7, prompt nearby cells to release IL-23, which in turn prevents the body's T-cells from attacking the tumor.

In order to eliminate the cancer, T-cells need to proliferate and destroy infected cells. But IL-23 stops them from working effectively, so the tumor keeps growing.

HPV16 E6 and E7 expressing cancer cells suppress the anti-tumor immune response by upregulating KLF2 mediated IL-23 expression in macrophages, Journal for ImmunoTherapy of Cancer (2025). DOI: 10.1136/jitc-2025-011915

Comment by Dr. Krishna Kumari Challa on August 20, 2025 at 8:49am

Maize plants use a volatile gas to fight off pests in densely crowded fields

When maize fields become too crowded, the plants signal each other to boost their defenses. A research team found that in crowded conditions, maize plants release a volatile gas called linalool into the air. When it reaches neighboring plants, the gas triggers a defensive response in their roots.

While planting crops close together can increase harvest size, it also increases the risk of pathogens and pests such as caterpillars and the African maize stalk borer. When this happens, maize crops don't stand idly by. It was already known that the plants can change their shape in crowded conditions, such as growing taller to get more sunlight, but less was known about their immune response.

The research team reports that in dense fields, linalool acts like an alarm bell, triggering the roots of neighboring plants to increase production of jasmonate and other plant hormones. This, in turn, leads to more benzoxazinoids leaking into the soil around the roots.

This class of plant chemical defense compounds alters the bacterial composition of the soil, thereby protecting the plants from pests. And the protective response is a speedy one, with increased defense against caterpillars observed after just three days of growth in high-density conditions.

However, as the researchers note from their field studies, there is a catch. This defensive boost comes at the cost of reduced growth as the plants put more of their resources into defense rather than growing.

The scientists also showed that soil modified by densely planted maize crops offered ongoing protection for new crops even against different pests. Later plantings were protected from nematodes and other pathogens, not just insects. This suggests that maize defense readiness persists in the soil long after the initial crop is harvested.

Dongsheng Guo et al, Linalool-triggered plant-soil feedback drives defense adaptation in dense maize plantings, Science (2025). DOI: 10.1126/science.adv6675

Niklas Schandry et al, The scent of a crowd, Science (2025). DOI: 10.1126/science.adz7633

Comment by Dr. Krishna Kumari Challa on August 19, 2025 at 1:45pm

Early lead exposure could result in memory issues later in life

A new study has found that people who lived in areas with high levels of leaded gasoline emissions in the 1960s and '70s are more likely to report memory problems today—a finding that researchers say could deepen our understanding of environmental risks tied to dementia.

The study and others presented in July at the 2025 Alzheimer's Association International Conference used data from more than 600,000 participants .

Participants who lived in areas with higher estimated lead emissions—often tied to dense traffic and industrial zones—were significantly more likely to report poor memory. 

Lead has long been known to affect brain development in children. But research into its long-term effects on aging brains is still emerging.

Lead is bad for lots of things. There's been some studies that suggest it's related to IQ generally, and also aggression and lots of other things in animal model studies.

IQ is not the only area where lead exposure damages us. Instead, it often overlaps with other social determinants of health, like poverty and poor housing, making it difficult to isolate one factor. Higher levels of exposure and living near environmental pollutants often correlate to those with lower incomes.

Comment by Dr. Krishna Kumari Challa on August 19, 2025 at 1:39pm

How a Brain Implant and AI Gave a Woman with Paralysis Her Voice Back

Comment by Dr. Krishna Kumari Challa on August 19, 2025 at 1:24pm

Vaccines trigger rapid lymph node responses, researchers discover

Lymph nodes are a key part of the human immune system, whose primary function is to combat infections. The effectiveness of vaccines is based on their ability to trigger events in lymph nodes that lead to the development of an immune response that protects the host against pathogens.

Researchers observed that lymphatic endothelial cells and other stromal cells are the first cells in the lymph nodes to come into contact with vaccines. The vaccines induced several changes in stromal cells at the gene and protein levels within the first hours of vaccination, which in turn affected lymph node function.

The changes in the stromal cells were observed before the development of the protective immune response triggered by the vaccine.

The researchers also discovered that different vaccines activate lymph node stromal cells in different ways.  

Ruth Fair-Mäkelä et al, COVID-19 vaccine type controls stromal reprogramming in draining lymph nodes, Science Immunology (2025). DOI: 10.1126/sciimmunol.adr6787

Comment by Dr. Krishna Kumari Challa on August 19, 2025 at 1:21pm

How AI support can go wrong in safety-critical settings

When it comes to adopting artificial intelligence in high-stakes settings like hospitals and airplanes, good AI performance and brief worker training on the technology is not sufficient to ensure systems will run smoothly and patients and passengers will be safe, a new study suggests.

Instead, algorithms and the people who use them in the most safety-critical organizations must be evaluated simultaneously to get an accurate view of AI's effects on human decision making, researchers say.

The team also contends these evaluations should assess how people respond to good, mediocre and poor technology performance to put the AI-human interaction to a meaningful test—and to expose the level of risk linked to mistakes.

During tests, results showed that more accurate AI predictions about whether or not a patient was trending toward a medical emergency improved participant performance by between 50% and 60%. But when the algorithm produced an inaccurate prediction, even when accompanied by explanatory data that didn't support that outcome, human performance collapsed, with an over 100% degradation in proper decision making when the algorithm was the most wrong.

An AI algorithm can never be perfect. So if you want an AI algorithm that's ready for safety-critical systems, that means something about the team, about the people and AI together, has to be able to cope with a poor-performing AI algorithm.

The point is this is not about making really good safety-critical system technology. It's the joint human-machine capabilities that matter in a safety-critical system

While the overall results provided evidence that there is a need for this type of evaluation, the researchers said they were surprised that explanations included in some experimental conditions had very little sway in participant concern—instead, the algorithm recommendation, presented in a solid red bar, overruled everything else.

Whatever effect that those annotations had was roundly overwhelmed by the presence of that indicator that swept everything else away.

Dane A. Morey et al, Empirically derived evaluation requirements for responsible deployments of AI in safety-critical settings, npj Digital Medicine (2025). DOI: 10.1038/s41746-025-01784-y

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