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  • nuclear fusion will soon power the world

    nuclear fusion will soon power the world

    Justin RowlattClimate Editor

    BBC/Pol Reygaerts Chris Wright is on the left and Justin Rowlatt is on the right. They sit facing each other in what looks like a study on wooden armchairs. Wright wears a grey suit with white tie and red shirt and Rowlatt wears a grey suit.BBC/Pol Reygaerts

    US Energy Secretary Chris Wright spoke to BBC Climate Editor Justin Rowlatt dureing an interview in Brussels

    Don’t worry too much about planet-warming emissions, the US Energy Secretary has told the BBC, because within five years AI will have enabled the harnessing of nuclear fusion – the energy that powers the sun and stars.

    Chris Wright told me in an interview that he expected the technology to deliver power to electricity grids around the world within eight to 15 years and that it would rapidly become a big driver of greenhouse gas reductions.

    His claims will likely surprise even enthusiasts for the technology.

    Harnessing the energy released when atoms fuse together could produce vast amounts of low carbon energy but most scientists believe commercial fusion power plants are still a long way off.

    “With artificial intelligence and what’s going on at the national labs and private companies in the United States, we will have that approach about how to harness fusion energy multiple ways within the next five years,” said Mr Wright.

    “The technology, it’ll be on the electric grid, you know, in eight to 15 years.”

    Scientists believe nuclear fusion, which Mr Wright studied at university, could one day produce vast amounts of energy without heating up our atmosphere.

    But it’s a very complex process. Replicating it on Earth involves heating atoms to temperatures many times hotter than the sun.

    President Donald Trump’s controversial energy chief also urged the UK government to lift the de facto ban on fracking and issue new oil and gas licenses in the North Sea.

    The US Energy Secretary warned the Trump Administration had “serious concerns” about Europe’s reliance on Chinese renewable technologies.

    “It looks like the Chinese could control what’s going on with your energy system,” he said.

    He repeated the claims made by Donald Trump that the UK and Europe’s effort to transition away from fossil fuels to low carbon energy is driving deindustrialisation and impoverishing their citizens.

    Mr Wright is in Brussels ahead of Donald Trump’s second state visit to the UK next week. The US President will meet Prime Minister Sir Keir Starmer and will attend a banquet hosted by King Charles at Windsor Castle.

    Getty Images An aerial view of a photovoltaic solar farm sprawling across undulating green hills in Shandong Province, China. The are also several white wind turbines rising in the background. A winding road curves through the lower foreground.Getty Images

    China leads the world in solar technology and exports. The US Energy Secretary warned the Trump administration had “serious concerns” about Europe’s reliance on its renewable technologies

    During the BBC interview the US Energy Secretary said fracking – releasing oil and gas trapped rock formations underground – could have a “tremendous” impact on the UK economy.

    Mr Wright, who has founded and run fracking companies in the US, suggested the oil and gas the process would produce could “bring back manufacturing and blue-collar jobs and drive down not just electricity prices, but home-heating prices and industrial energy prices”.

    Reform UK recently said it would encourage fracking in the UK if it were to win the next election, but the British Geological Survey has warned the potential for the technology to produce large amounts of oil and gas in the UK is likely to be limited.

    Mr Wright defended the billions of dollars of cuts the Trump Administration has made to renewable energy subsidies. He said wind power has been subsidised for 33 years and solar for 25 years.

    “Isn’t that enough?” the Energy Secretary asked: “You’ve got to be able to walk on your own after 25 to 30 years of subsidies.”

    Getty Images U.S. President Donald Trump holds up a signed executive order during a ceremony, with officials applauding in the background.Getty Images

    US Energy Secretary Chris Wright stands behind President Donald Trump as he holds an executive order

    The Energy Secretary also stood by the report issued by the Department of Energy in July which said the threat of climate change has been exaggerated.

    Among a series of controversial claims, the report said sea level rise is not accelerating, that computer models of the climate exaggerate future temperature rises and that climate scientists overlook beneficial aspects of climate change like the fact that high densities of carbon dioxide promote plant growth.

    Earlier this month more than 85 international scientists claimed it was riddled with errors and misrepresentations and that data had been “cherry-picked” – selectively chosen. The scientists also called into question the academic standards of the five authors of the paper.

    Mr Wright told the BBC he believes it is climate scientists who use data selectively. “Cherry-picking data in climate science, in the media, by activists and by politicians is the norm,” he said.

    He acknowledged that climate change is a “very real, physical phenomenon” and said that he believes the world will decarbonise: “It’s just generations from now, not two or three decades from now.”

    He said he was delighted his report had prompted such vigorous debate: “We’ve got a dialogue back and forth about climate change in a public forum. I’ve wanted that for 20 years.”

    He denied that the cuts the Trump Administration is making to climate science, including a proposal to slash the funding for the US’s National Oceanic and Atmospheric Administration (NOAA), would damage US research into weather and climate.

    There has been speculation that the cuts could block the development of the next generation of weather satellites and could even lead to the closure of the Mauna Loa Observatory in Hawaii, which is responsible for the longest record of direct measurements of CO2 concentrations in the atmosphere.

    “There are a lot of rumours about all sorts of terrible things happening,” said Mr Wright, who claimed the US government is trying to restore “real science”.

    He claimed: “One of the problems of science is it’s become so politicised in the climate world, if you deviate from the church, your funding gets cut off.”

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  • Physicists Predict a Black Hole Could Explode This Decade

    Physicists Predict a Black Hole Could Explode This Decade

    Physicists at the University of Massachusetts Amherst have challenged long-held assumptions about black holes and now estimate up to a 90% chance of observing a primordial black hole explosion within the next decade. (Artist’s concept). Credit: SciTechDaily.com

    UMass Amherst physicists believe such an explosion could occur within the next decade, potentially “revolutionizing physics and rewriting the history of the universe.”

    Physicists have long thought that black holes end their lives in rare explosions that occur, at most, once every 100,000 years. New research in Physical Review Letters from University of Massachusetts Amherst physicists points to a different outlook. The team estimates a probability greater than 90% that one such explosion could be observed within the next decade. If observers prepare in advance, today’s space and ground observatories should be able to capture the event.

    Such a blast would strongly support the existence of a theorized but never directly observed kind of black hole called a “primordial black hole,” which may have formed less than a second after the Big Bang 13.8 billion years ago.

    The explosion could also deliver a definitive inventory of all subatomic particles. That list would include known particles such as electrons, quarks, and Higgs bosons, proposed particles like dark matter candidates, and anything else that is currently unknown to science. With such a catalog, researchers could finally tackle one of humanity’s oldest questions: where did everything come from?

    Understanding Black Holes

    We know that black holes exist, and we have a good understanding of their life cycle: an old, large star runs out of fuel, implodes in a massively powerful supernova, and leaves behind an area of spacetime with such intense gravity that nothing, not even light, can escape. These black holes are incredibly heavy and are essentially stable.

    But, as physicist Stephen Hawking pointed out in 1970, another kind of black hole—a primordial black hole (PBH), could be created not by the collapse of a star but from the universe’s primordial conditions shortly after the Big Bang. PBHs, like the standard black holes, are so massively dense that almost nothing can escape them—which is what makes them “black.” However, despite their density, PBHs could be much lighter than the black holes we have so far observed. Furthermore, Hawking also showed that black holes have a temperature and could, in theory, slowly emit particles via what is now known as “Hawking radiation” if they got hot enough.


    This artist’s concept takes a fanciful approach to imagining small primordial black holes. In reality, such tiny black holes would have a difficult time forming the accretion disks that make them visible here. Credit: NASA’s Goddard Space Flight Center

    “The lighter a black hole is, the hotter it should be and the more particles it will emit. As PBHs evaporate, they become ever lighter, and so hotter, emitting even more radiation in a runaway process until explosion. It’s that Hawking radiation that our telescopes can detect,” says Andrea Thamm, co-author and assistant professor of physics at UMass Amherst.

    Yet, while we should be able to, no one has ever directly observed a PBH.

    “We know how to observe this Hawking radiation,” says Joaquim Iguaz Juan, a postdoctoral researcher in physics at UMass Amherst. “We can see it with our current crop of telescopes, and because the only black holes that can explode today or in the near future are these PBHs, we know that if we see Hawking radiation, we are seeing an exploding PBH.”

    A Paradigm Shift in Expectations

    Though physicists since Hawking’s time have thought that the chances of seeing an exploding PBH are infinitesimally slight, Iguaz Juan notes that “our job as physicists is to question the received assumptions, to ask better questions and come up with more precise hypotheses.”

    The team’s new hypothesis? Get ready now to see the explosion. “We believe that there is up to a 90% chance of witnessing an exploding PBH in the next 10 years,” says Aidan Symons, one of the paper’s co-authors and a graduate student in physics at UMass Amherst.

    In its work, the team explores a “dark-QED toy model.” This is essentially a copy of the usual electric force as we know it, but which includes a very heavy, hypothesized version of the electron, which the team calls a “dark electron.”

    The team then reconsidered long-held assumptions about the electrical charge of black holes. Standard black holes have no charge, and it was assumed that PBHs are likewise electrically neutral.

    “We make a different assumption,” says Michael Baker, co-author and an assistant professor of physics at UMass Amherst. “We show that if a primordial black hole is formed with a small dark electric charge, then the toy model predicts that it should be temporarily stabilized before finally exploding.” Taking all known experimental data into account, they find that we could then potentially observe a PBH explosion not once every 100,000 years as previously thought, but once every 10 years.

    “We’re not claiming that it’s absolutely going to happen this decade,” says Baker, “but there could be a 90% chance that it does. Since we already have the technology to observe these explosions, we should be ready.”

    Iguaz Juan adds, “This would be the first-ever direct observation of both Hawking radiation and a PBH. We would also get a definitive record of every particle that makes up everything in the universe. It would completely revolutionize physics and help us rewrite the history of the universe.”

    Reference: “Could We Observe an Exploding Black Hole in the Near Future?” by Michael J. Baker, Joaquim Iguaz Juan, Aidan Symons and Andrea Thamm, 10 September 2025, Physical Review Letters.
    DOI: 10.1103/nwgd-g3zl

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  • Will farming under solar panels take off?

    Will farming under solar panels take off?

    Priti GuptaTechnology Reporter

    Harpal Dagar Wearing a brown beanie hat and white sports jacket, Harpal Dagar holds up, either side of him, two large, white root vegetables. Behind him you can see solar panels, on frames, about 12 feet in the air.Harpal Dagar

    Harpal Dagar has been farming under solar panels for five years

    “As a farmer, you’re always at the mercy of weather,” says Harpal Dagar who has a farm on the outskirts of Delhi.

    “So many times, we lost our produce due to unpredictable conditions,” he says.

    But five years ago he was approached by Sun Master, a Delhi-based solar power firm, with a deal that would give him a much more predictable income.

    Sun Master proposed building solar panels above some of Mr Dagar’s fields, with the panels high enough off the ground, that he could continue to farm underneath them.

    Under the 25-year deal, Mr Dagar would receive annual payments and Sun Master would keep the proceeds from the electricity generated.

    “When the solar company first approached us… many of us feared losing our land. It sounded too good to be true – maybe even a scam,” says Mr Dagar.

    “But today, I believe it was the best decision I made. My income has tripled, and I sleep peacefully without the stress of climate or crop failure,” he says.

    Sun Master pays him around $1,200 (£900) per acre, per year, plus $170 a month for work operating and maintaining the solar panels.

    “Even the turmeric I grow on the same land is mine to sell. How can I complain?”

    Siting solar panels above crops goes by the term agrivoltaics.

    India would seem particularly suited to such innovation. The fortunes of many of its farmers often hinge on an unpredictable monsoon, so a reliable income from a solar energy firm might provide some welcome financial security.

    But despite the benefits, take up has been slow, around 40 projects are operating in India at the moment, according to the National Solar Energy Federation of India (NSEFI), which represents India’s solar power industry.

    There are several challenges.

    Not all crops will grow under solar panels. Depending on the layout, the panels reduce the light getting through by between 15% and 30%. Some denser layouts will block too much sun for staple crops including wheat, rice, soybeans or pulses.

    “What works well are high-value crops with moderate or low-light needs, like green leafy vegetables, spices such as turmeric and ginger, and some flowers,” says Vivek Saraf, the founder and CEO of Delhi-based SunSeed, which specialises in agrivoltaics.

    There’s also the issue of expense.

    To allow farming underneath, the solar panels need to be at least 11ft (3.5m) off the ground. That makes them between 20% and 30% more expensive to install than panels on a regular solar farm, where they are much closer to the ground.

    “Small farmers cannot own these systems. They don’t have the risk appetite or capital,” says Mr Saraf.

    SunSeed APV Tomatoes on a vine, some green some red and behind solar panels suspended on pillars. SunSeed APV

    SunSeed promises to take the risk out of farming

    The solar power companies want the government to step in with subsidies to make agrivoltaics more attractive.

    “In India, where more than 55% of the population depends on agriculture and cultivable land is under mounting pressure, agrivoltaics offers a transformative model,” says Subrahmanyam Pulipaka, CEO of NSEFI.

    “It reduces irrigation needs, shields crops from heat stress, and stabilizes incomes by diversifying revenue streams for farmers. For rain fed and climate-vulnerable regions, agrivoltaics can play a vital role in climate adaptation, making agriculture more resilient to unpredictable weather patterns,” he says.

    SunSeed gives the farmer multiple options, including continuing to farm for a fixed salary, or handing over all the farming responsibility to SunSeed.

    “Our model ensures the farmer is not exposed to any risk. If the crop fails or there’s a market issue, the loss is ours – not the farmers’,” he says.

    Meanwhile, SunSeed has been finely tuning its system to work with different crops and conditions.

    “We have developed sophisticated agrivoltaics simulation software,” he says.

    “It digitally replicates panel configurations and crop types to simulate how much light and heat each leaf receives, how photosynthesis is affected, and ultimately how much yield to expect.”

    SunSeed Yellow flowers grow in rows underneath solar panels.SunSeed

    Agrivoltaic projects are still relatively rare in India

    There’s still caution in government circles over the combination of solar power and farming.

    “Agrivoltaics is promising, but we must protect both the farmer and the developer,” says Manu Srivastava, who oversees solar and agrivoltaic projects in the state of Madhya Pradesh.

    “The biggest challenge is contracts. A 25-year lease needs clear obligations and protection for both sides. In India, long-term contract enforcement is still a hurdle,” says Mr Srivastava.

    He also points out that agrivoltaics systems are more expensive than a traditional ground-mounted solar farm, so making a return on the investment is more challenging.

    “If the farmer starts charging too much for land and the developer has to bear high structural costs, then it becomes unviable,” he says.

    At the moment India is falling behind China, where more than 500 projects are in operation, according to the World Resources Institute.

    “It’s a small beginning. But if the farmer’s economic interest is protected, if the right crops are chosen, and if contracts are clear and fair, there’s no reason India can not lead in agrivoltaics,” says Mr Srivastava.

    Anand Jain Rows of solar panels supported by 12-feet high pillars stand in a field. In the foreground a man speaks on his phone. Rows of plants grow close to the ground beneath the solar panels. Anand Jain

    Anand Jain has been growing strawberries and tomatoes under solar panels

    Anand Jain comes from a family of farmers. He was growing medicinal herbs, but in 2024 he found a plot of land with no electricity.

    “That’s when the idea clicked. Necessity is the mother of invention, and that’s how I began experimenting with agrivoltaics.”

    Today he has 14 acres of farmland under solar panels. The farm has a total generation capacity of 4.5 megawatts, about the same as a medium-sized wind turbine.

    Underneath he is still experimenting with crops, he hasn’t sold any at the market yet but says the quality is “promising”.

    “I’ve had success with strawberries and tomatoes, although cauliflower didn’t work out as well.”

    The project was funded with bank loans and support from the government, in all an investment of $2.27m.

    “Let me be clear – agrivoltaics isn’t yet feasible for small farmers in India,” he says.

    “This model will only succeed if there is a strong partnership between the government and the private sector.”

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  • Short Sellers Target China’s Haidilao on Dimmer Growth Outlook

    Short Sellers Target China’s Haidilao on Dimmer Growth Outlook

    Bearish wagers on Haidilao International Holding Ltd. have surged as investors scrutinize the Chinese hotpot chain’s long-term growth outlook.

    The stock’s short interest as a percentage of free float is hovering around 11%, putting it near the highest level in three years, according to S&P Global data. That also makes it the third-most shorted firm on the Hang Seng China Enterprises Index.

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  • Hong Kong Stock ETFs Get Record China Money on AI, Biotech Craze

    Hong Kong Stock ETFs Get Record China Money on AI, Biotech Craze

    Hot themes from artificial intelligence to biotech have driven Chinese investors to pour record amounts of cash into locally listed exchange-traded funds that track Hong Kong stocks, a trend that analysts say is likely to continue.

    Inflows into onshore-listed Hong Kong ETFs have reached over $26 billion so far this year, with an accelerated buying spree since June, Bloomberg Intelligence-compiled data show. Mainland retail traders are being lured by the outperformance of the city’s equities combined with their accessibility and abundance of new products to choose from.

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  • Cheap Yuan Funding Is Tempting More Borrowers Outside of China

    Cheap Yuan Funding Is Tempting More Borrowers Outside of China

    As Hungary embarks on building railways that link car factories to new markets in western Europe, the country is turning to financing in China.

    It’s a similar story in Kazakhstan, where the state-owned oil producer is planning its debut yuan bond saleBloomberg Terminal. In Kenya, officials hope to soon ink a deal letting the cash-strapped country convert its dollar debt for Chinese currency loans in exchange for more time to repay.

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  • Ed Sheeran: Play review – subcontinental sounds and shards of darkness – but still unmistakably him | Ed Sheeran

    Ed Sheeran: Play review – subcontinental sounds and shards of darkness – but still unmistakably him | Ed Sheeran

    As he points out on the opening track of Play, Ed Sheeran has now been around a long time. It’s 20 years since he self-released his debut album and 14 since he signed to a major label and set about becoming the most commercially successful British artist of his age: long enough that we’re now seeing the appearance of pop stars who claim him as a formative influence. (Singer-songwriter Myles Smith, who was just into his teens when Sheeran released his breakthrough album +, even plays one of those little acoustic guitars that have long been Sheeran’s trademark.) It’s certainly long enough that anyone with even a passing interest knows what to expect when Ed Sheeran releases a new album.

    Ed Sheeran: Play. Photograph: AP

    Sheeran’s success is based on a certain dependability: it doesn’t seem to matter who he works with – Pharrell Williams, Eric Clapton, Eminem, the National’s Aaron Dessner – the results always somehow sound exactly like Ed Sheeran. Whether you see that as evidence of a melodic signature so strong it rings out regardless of the musical setting or a failure of artistic imagination depends on whether you’re among those who contributed to his cumulative sales figures of 200m, or part of the vociferous cadre who view him as the embodiment of all that’s wrong with music. The latter camp gets a shout-out on Play’s prosaically titled opening track Opening, essentially an older, more battered counterpart to You Need Me, I Don’t Need You, the 2011 track that bullishly asserted his bona fides: “Not the pop star they say they prefer,” Sheeran raps.

    Solid, dependable: these are adjectives one could apply to Play. His last two albums, 2023’s muted – and Autumn Variations, were made with Dessner, the co-architect of Taylor Swift’s folksy lockdown albums: the former was Sheeran’s most acclaimed record critically, but the public seemed less convinced. Play has a sense of reassuring the shareholders about it: the big story is that Sheeran went to Goa to complete it, but – as with single Azizam’s diversion into Persian music – the sounds of the subcontinent that have soaked into the end product feel like window dressing.

    There’s traditional Indian percussion here and there, most notably on Heaven, plus Hindi and Punjabi vocals and a guest appearance from Bengali singer Arijit Singh on Sapphire, but none of it really overwhelms the tracks’ essential Ed Sheeran-ness: the former is sweetly emotive, the latter the kind of uptempo Ed Sheeran song that’s a little too eager to please and ends up slightly grating. Tablas and Hindi lyrics or not, no one is ever going to wonder who made them, particularly when they’re scattered among more traditional fare, which ranges in quality from ho-hum (the acoustic guitar-led ruminations of Old Phone) to exceptionally well crafted: the ruthlessly effective power balladry of Camera and The Vow, the lo-fi piano of In Other Words, the latter another contribution to a now-teetering pile of Sheeran songs that might have been designed for newlywed first dances.

    Ed Sheeran: Sapphire – video

    And the tracks recorded in India feel less striking than two songs made closer to home. A collaboration with Fred Again, Don’t Look Down, fruitfully places Sheeran’s vocal amid luminous rave synths and, eventually, a pounding house beat. And highlight Symmetry opens with looped Indian percussion and vocals but quickly floats off in a different direction, involving spectral voices and heaving sub-bass. It’s not a radical reinvention, but you sense an artist pushing softly at boundaries.

    That said, Play is not incapable of springing genuine surprises: it comes as quite a jolt to hear Sheeran calling someone “a prick” on A Little More, then following it up with a line that definitely qualifies as a sick burn: “And for your dad’s sake, please move out your dad’s place.” The emotional temperature of Sheeran’s music to date has ranged from sorrowful to lovestruck. He’s never sounded angry. It’s unclear who the song is aimed at, or what they’ve done to rile him, but on A Little More, he seems genuinely livid: “I hate you … one day we’ll all be dead but between now and then I never want to see you again.” It’s both unexpected and weirdly bracing, its impact amplified by subtly effective electric piano and post-Amy Winehouse horns.

    A curiously dark emotional undercurrent keeps bubbling up throughout Play. There are allusions to Sheeran’s circle of friends contracting, to “leeches” and his heart being broken by “loved ones”. There are references to Sheeran’s much-noted professional drive that make it sound paranoid and compulsive – “if I look down I can see replacements … in this world there’s no relaxing” – and there’s Slowly, ostensibly just a song about missing his wife when she’s away “for a couple of days” that expresses itself in such extreme terms as to feel quite disturbing: “kill me slowly”, “this is knife-in-the-heart love”, “I’m dying alive”.

    Of course, these tinges of darkness are unlikely to impact on Play’s commercial success. All its preceding singles already have streaming figures that look like phone numbers. But it does mean you leave it wondering what on earth is going on: the last feeling one expects to get from an Ed Sheeran album.

    This week Alexis listened to

    Gruff Rhys – Taro #1 + #2
    A highlight from his new Welsh-language album Dim Probs: the cocktail of laid-back west coast rock meets motorik drums plus new wave-y sax is a peculiar one that nevertheless slips down smoothly.

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  • Streaming Ratings Aug. 11-17, 2025

    Streaming Ratings Aug. 11-17, 2025

    Wednesday stayed at the top of the streaming charts in the second week after season two’s premiere, but it wasn’t as dominant as it was for its opening frame. FX’s Alien: Earth also joined the rankings with its debut on Hulu.

    After logging the second-largest weekly total of 2025, Wednesday fell by about 43 percent for the week of Aug. 11-17 — though it still drew a strong 2.14 billion minutes of watch time in the United States, according to Nielsen. The CTV/CW drama Sullivan’s Crossing moved back up the charts a week after its third season debuted on Netflix, logging 1.59 billion minutes for second place overall. KPop Demon Hunters continued its huge summer with 1.02 billion viewing minutes.

    Related Stories

    Alien, Sigourney Weaver, 1979, piloting the spaceship

    Alien: Earth premiered to 464 million minutes of watch time on Hulu for its first two episodes. That was good for seventh place among originals, just behind another debut: Prime Video’s spy thriller Butterfly (491 million minutes), starring Daniel Dae Kim.

    The previous week’s second- and third-ranked original series, King of the Hill and The Hunting Wives, swapped spots. The Hunting Wives scored 761 million minutes of watch time for Netflix, while King of the Hill had 714 million minutes for Hulu.

    Nielsen’s streaming ratings cover viewing on TV sets only and don’t include minutes watched on computers or mobile devices. The ratings only measure U.S. audiences, not those in other countries. The top streaming titles for Aug. 11-17, 2025, are below.

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  • Scientists uncover brain circuit that turns cravings into eating behavior

    Scientists uncover brain circuit that turns cravings into eating behavior

    Scientists uncovered how the brain’s bed nucleus of the stria terminalis acts as a master switchboard, merging reward and need signals to control eating, a discovery that could guide new treatments for obesity and illness-related weight loss.

    Study: A brain center that controls consummatory responses

    In a recent study published in the journal Cell, a group of researchers tested whether the bed nucleus of the stria terminalis (BNST) integrates central amygdala (CEA) prodynorphin (Pdyn) and hypothalamic agouti-related peptide (AGRP) signals to control consumption, with downstream consequences for body weight.

    Background

    Cravings seem simple—see sugar, want sugar—but the choice to actually consume is a brain-wide negotiation. People feel it when a dessert is irresistible while hungry, yet forgettable after lunch. Public health feels it amid obesity, appetite-blunting cancer therapies, and satiety drugs. A question follows: where do “this tastes good” and “my body needs it” meet? The BNST is a switchboard that integrates sensory valence with internal state to regulate consumption. Knowing how this works could help counter illness-related weight loss and refine anti-obesity treatments. Further research is needed to map input specificity and state-dependent rules across nutrients.

    About the study

    The investigators first identified CEA neurons encoding sweet valence using Act-seq single-cell ribonucleic acid sequencing (scRNA-seq) and immediate-early gene Fos co-expression to identify sweet-responsive CEA neurons co-expressing Fos and Pdyn. They recorded activity from these neurons with adeno-associated virus (AAV)-delivered circularly permuted green fluorescent protein-calmodulin-M13 peptide calcium indicator 6s (GCaMP6s) and fiber photometry while delivering tastants via an intraoral fistula. To test causality, they expressed channelrhodopsin-2 (ChR2) or the inhibitory anion channelrhodopsin GtACR2 in Pdyn neurons and coupled activation or silencing to licking or lever-press tasks. Anterograde tracing mapped projections from CEA Pdyn neurons to the BNST. Responses within the BNST were dissected by targeting the vesicular gamma-aminobutyric acid transporter (VGAT) population and performing fiber photometry and optogenetics.

    The convergence of internal-state signals was tested using monosynaptic rabies tracing from BNST VGAT neurons and by optogenetically stimulating agouti-related peptide (AGRP) neurons in the arcuate nucleus (ARC) that express ChrimsonR. Microendoscopic calcium imaging with a gradient refractive index (GRIN) lens quantified ensemble coding across fed, hungry, and sodium-depleted states. Finally, chemogenetics (designer receptors exclusively activated by designer drugs (DREADDs), hM3Dq; clozapine N-oxide (CNO)) and a pharmacologically selective actuator module 4–4-glycine receptor (PSAM4-GlyR) plus its ligand ultrapotent Pharmacologically Selective Effector Molecule 792 (uPSEM792) tested whether BNST modulation alters food intake and body weight in cisplatin-treated or diet-induced-obese mice.

    Study results

    Pdyn-positive neurons in the CEA encoded attraction to sweet: optogenetic activation made otherwise neutral water highly sought, and silencing abolished preference for both artificial sweetener and sugar while leaving fat preference intact, demonstrating modality specificity. Dense projections from these CEA Pdyn neurons to the BNST were mapped; within BNST, VGAT neurons responded robustly and selectively to sweet stimulation. Optogenetic stimulation of Pdyn terminals in the BNST increased licking to water, establishing a causal link between amygdala sweet coding and consumption; conversely, inhibiting BNST VGAT neurons suppressed sweet intake. Importantly, the Pdyn to BNST circuit did not drive dry-licking when no fluid was available, indicating consummation rather than pure reward seeking, whereas activating Pdyn somata in the CEA did evoke dry-licking self-stimulation by engaging additional reward-related targets.

    Internal state powerfully reweighted BNST processing. Hunger amplified sweet-evoked responses in BNST and boosted consumption by approximately 250–300%, while TRPM5 knockout mice did not show this effect; stimulating AGRP inputs to BNST in sated mice mimicked this enhancement, recruiting previously silent sweet-responsive BNST neurons and supporting convergence of taste and need signals within BNST. Retrograde monosynaptic tracing corroborated direct inputs from the CEA and the ARC to BNST VGAT neurons. Beyond hunger, sodium depletion selectively increased BNST responses to sodium chloride (NaCl) by ~300% and shifted behavior toward salt seeking, revealing state-specific gating for need.

    At the population level, microendoscopic single-cell calcium imaging revealed that internal states recruit additional BNST neurons without significantly altering individual response amplitudes, thereby expanding the ensemble representing sweet during hunger. A softmax decoder trained on BNST activity separated stimulus identity (sweet vs. salt) and internal state (fed, hungry, sodium-depleted), achieving ~80% accuracy overall and showing that BNST ensembles jointly encode “what” and “need.”

    Causally, the BNST behaved as a general consumption controller: optogenetic activation of BNST VGAT neurons drove broad intake, including solid food, sweet, high-sodium water, normally aversive bitter substances, and even fictive food pellets, whereas silencing suppressed consummatory behavior irrespective of the stimulus or state. Translational tests underscored clinical relevance. In a cisplatin model that induces cachexia-like weight loss, chemogenetic activation of BNST VGAT neurons preserved body weight. Conversely, chemogenetic inhibition of BNST induced weight loss in diet-induced obese mice, an effect that reversed when inhibition ceased. A glucagon-like peptide-1 receptor (GLP-1R) agonist, semaglutide, induced Fos selectively in protein kinase C delta (PKCδ)-positive BNST neurons, suggesting that these neurons are a potential site contributing to the anti-obesity drug action. Together, these data define the BNST as a unified “consumption dial” that flexibly integrates appetitive value and internal need to drive consummatory responses.

    Conclusions

    To summarize, this work positions the BNST as a control hub that turns liking into eating by merging sensory valence from CEA Pdyn neurons with need signals from AGRP neurons. Clinically, a bidirectional lever over consumption suggests ways to counter cancer-therapy-related wasting or, oppositely, to promote weight loss by inhibition. The association of GLP1R agonism with PKCδ–positive BNST neurons highlights a mechanistic waypoint for anti-obesity drugs.

    Journal reference:

    • Canovas, J. A., Wang, L., Mohamed, A. A. M., Abbott, L. F., & Zuker, C. S. (2025). A brain center that controls consummatory responses. Cell. DOI: 10.1016/j.cell.2025.08.021, https://www.cell.com/cell/fulltext/S0092-8674(25)00976-6

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  • Comparative Effectiveness and Safety of Intravenous Versus Oral Iron Therapy With Iron-Deficient Heart Failure: A Network Meta-Analysis of Randomized Controlled Trials

    Comparative Effectiveness and Safety of Intravenous Versus Oral Iron Therapy With Iron-Deficient Heart Failure: A Network Meta-Analysis of Randomized Controlled Trials


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