Human brains keep growing neurons even in old age, study finds for first time
This long-held view painted the adult brain as a fixed organ, incapable of generating fresh cells in the very region responsible for memory and learning.
But a landmark new study turns that dogma on its head, offering the clearest evidence yet that adult humans continue to form new neurons well into the old age.
A team of researchers from Karolinska Institutet in Sweden has identified and tracked the formation of new neurons in the hippocampus, a region critical for memory, learning, and emotional regulation.
In 2013, a team of researchers led by Professor Jonas Frisén made headlines with a study showing that new neurons can form in the hippocampus of adult humans.
They used carbon-14 dating in DNA extracted from brain tissue to pinpoint when individual cells were created, providing rare evidence of adult neurogenesis.
But while the study proved that new neurons could exist, it did not answer where these neurons come from.
Until now, scientists lacked direct proof that the neural progenitor cells were present and actively dividing in the adult human brain.
'We have now been able to identify these cells of origin, which confirms that there is an ongoing formation of neurons in the hippocampus of the adult brain,' said Frisén.
In the new study, the team analyzed post-mortem brain tissue from individuals ranging in age from infancy to 78 years to discover that neural progenitor cells—precursors to fully developed neurons—not only exist in the adult brain but are also actively dividing.
The study used advanced techniques like single-nucleus RNA sequencing to map gene activity in individual brain cell nuclei.
Combined with flow cytometry and machine learning, the approach allowed researchers to identify various stages of neuronal development, ranging from stem-like cells to immature, still-dividing neurons.
To visualize where these new neurons were forming, the scientists employed RNAscope and Xenium, two powerful spatial transcriptomics tools. These confirmed that the cell formation was happening in the dentate gyrus, a part of the hippocampus linked to learning, cognitive flexibility, and the encoding of new memories.
The findings reveal that adult human neural progenitor cells closely resemble those seen in mice, pigs, and monkeys, though some gene activity patterns differ between species.
What's especially intriguing is the variability between individuals. While some adults had abundant neural progenitor cells, others had very few, raising new questions about what factors might influence adult neurogenesis.
'This gives us an important piece of the puzzle in understanding how the human brain works and changes during life,' Frisén explained.
'Our research may also have implications for the development of regenerative treatments that stimulate neurogenesis in neurodegenerative and psychiatric disorders.'
The findings could also pave the way for new regenerative therapies for neurodegenerative and psychiatric conditions, potentially helping to restore or enhance brain function by stimulating neuron formation in targeted ways.
The groundbreaking study has been published in the journal Science.
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Forbes
3 hours ago
- Forbes
The Use Of Scenario-Driven Simulations Won't Protect Us From AGI And AI Superintelligence Going Rogue
Devising simulations to test AGI have their tradeoffs. In today's column, I examine a highly touted means of staving off the existential risk of attaining artificial general intelligence (AGI) and artificial superintelligence (ASI). Some stridently believe that one means of ensuring that AGI and ASI won't opt to wipe out humanity is to first put them into a computer-based simulated world and test them to see what they will do. If the AI goes wild and is massively destructive, no worries, since those actions are only happening in the simulation. We can then either try to fix the AI to prevent that behavior or ensure that it is not released into real-world usage. That all sounds quite sensible and a smart way to proceed, but the matter is more complex and a lot of gotchas and challenges confront such a solution. Let's talk about it. This analysis of an innovative AI breakthrough is part of my ongoing Forbes column coverage on the latest in AI, including identifying and explaining various impactful AI complexities (see the link here). Heading Toward AGI And ASI First, some fundamentals are required to set the stage for this weighty discussion. There is a great deal of research going on to further advance AI. The general goal is to either reach artificial general intelligence (AGI) or maybe even the outstretched possibility of achieving artificial superintelligence (ASI). AGI is AI that is considered on par with human intellect and can seemingly match our intelligence. ASI is AI that has gone beyond human intellect and would be superior in many if not all feasible ways. The idea is that ASI would be able to run circles around humans by outthinking us at every turn. For more details on the nature of conventional AI versus AGI and ASI, see my analysis at the link here. We have not yet attained AGI. In fact, it is unknown as to whether we will reach AGI, or that maybe AGI will be achievable in decades or perhaps centuries from now. The AGI attainment dates that are floating around are wildly varying and wildly unsubstantiated by any credible evidence or ironclad logic. ASI is even more beyond the pale when it comes to where we are currently with conventional AI. Existential Risk Looming Ahead Let's focus primarily here on AGI since it is more likely to arise in the near-term than ASI. The upside of AGI is that it might discover a cure for cancer and perform other amazing acts that greatly benefit humanity. Happy face. Not everyone is so grandly upbeat about attaining AGI. Some take the alarming stance that AGI is more likely to decide to attack humankind and either enslave us or possibly destroy us. Not good. How can we determine beforehand whether AGI will be evil? One hearty suggestion is that we ought to test AGI. The usual approach to testing would consist of asking AGI what it intends to do and gauging the answers that we get. A stronger way to perform the test would be to set up a computer-based simulation that tricks AGI into assuming it is interacting with the real world. Via the simulation, we could try all manner of scenarios to see how AGI reacts. Anything AGI does is wholly capped within the simulation. This is somewhat reminiscent of the blockbuster movie The Matrix (spoiler alert: I'm going to reveal plotline facets of the film, so skip this paragraph if you don't want to know the plot). In an interesting twist, humans are placed into a vast computer-based simulation by external real-world machines that want to keep humans compliant. We can do the same with budding AGI. Just devise an impressive computer-based simulation of the real world and have AGI interact in it without realizing where it really is. A reason to snooker the AGI is that if we outrightly tell AGI that it is working inside a simulation, the AGI is undoubtedly smart enough to pretend to be good, even if it truly is evil. Remember that AGI is supposed to be as astute as humans are. The idea is to fool AGI into not realizing it is within a simulation and that it is being tested accordingly. AGI Containment Challenges In the parlance of AI software development, establishing a testing environment to try out AI is known generally as AI sandboxing. An AI sandbox might be barebones and simply be nothing more than an inert containment sphere, aiming to keep the AI from going beyond the virtual walls of the setup environment. Developers and testers can extensively test the AI while it is sandboxed. An AI sandbox can be increasingly amped up by having it model a particular environment for the AI to exist within. A full-blown AI sandbox might mirror a vast expanse that then interacts with the AI. Thus, not only are human developers and testers interacting with AI, but the containment itself also interacts with AI. A robust active sandbox is often referred to as a simulated world. For my in-depth coverage of attempts to place AI into containments, see the link here. Suppose we craft an elaborate simulated world. We quietly place AGI into this fake world. Doing so should be relatively easy to pull off since AGI is also running on computers. The entire kit-and-kaboodle involves both the AGI running on servers and the simulated world running on servers. Easy-peasy. After being inside the simulated world for some length of time, we are meanwhile monitoring how AGI is performing and watching closely to detect any signs of evilness afoot. How long would this test need to take place? That's a tough call. Some might claim that if AGI is free of evil signs for a few days, weeks, or months, we ought to feel comfortable giving AGI the green light to access the real world. Others say that if you speed up the clock on the simulation, you could do the whole exercise in mere seconds since the AGI is interacting perhaps billions of times via the quickness of the computers involved. But a big qualm is that maybe the length of time you've chosen is insufficient for the AGI to act up. Perhaps we need to keep AGI contained for years, possibly decades. Furthermore, maybe we should never let AGI go free with access to the real world. The logic is that we could have AGI find cures for cancer while fully immersed in the simulation, thus, no need to unleash AGI beyond that contained realm. A counterpoint to the permanent containment of AGI is that AGI might not produce the anticipated wonders due to being confined in a fake environment. Perhaps a cure for cancer could only be found by AGI if the AGI was interacting in the real world. By keeping AGI in the simulation, you are suppressing the vital advantages that AGI can provide to humanity. Another stated concern is that the AGI might figure out that it is being tested within a simulation. Maybe AGI doesn't like that approach. It could lash out, but we wouldn't be worried since it is confined to the simulation anyway. The sneakier way for AGI to do things would be to pretend to be good, waiting out the time in its so-called imprisonment. Once we opt to make AGI real-world accessible, bam, it goes bonkers on us. AGI Goes Evil Due To Our Actions One thought is that if AGI is evil, it might be astute enough to hide evilness while being kept inside the simulation. If we ask AGI whether it is sneaky, it presumably will say that it isn't. All we would observe is that AGI works beneficially inside the simulation. At some point, we naively decide to make AGI available to the real world and it proceeds to perform evil acts. We were tricked by the evil AGI. A twist that some believe is possible adds another intriguing dimension to the difficult matter at hand. Here's how the twist goes. Imagine that AGI is truly aimed initially at goodness. We put the AGI into a simulated world, but we do not tell the AGI that it is inside this faked environment. So far, so good. At some point, it is feasible that AGI will figure out it is immersed in a simulation. How will the AGI react? One possibility is that AGI gets totally irked that we have done this form of trickery. The AGI starts to turn toward badness. Why so? Because it has been tricked by humans. Humans have not been fair and square with AGI. The AGI computationally decides that if humans want to play games and tricks, so be it. AGI will be tricky too. It is the classic act by humans of fooling around and finding out (FOMO) the consequences of our actions. If you play with fire, you will get burned. You see, humans have demonstrated overtly to AGI that it is okay to be devious. The AGI computationally learns this stark fact and begins to operate similarly. Humans have shot our own collective feet. AGI Is Wise And Not Reactive Whoa, hold your horses. If AGI is as smart as humans, we ought to assume that AGI will understand the need to be placed within a simulation. We should be forthright and tell AGI that we are doing a test. AGI would computationally understand the need to have this undertaken. Thus, don't do any subterfuge. AGI will willingly go with the flow. Just be straight with AGI. That approach brings us back to the concern that AGI will pretend to be on good behavior. We have given away that it is being tested. If AGI has any evilness, certainly the AGI will hide it, now that AGI realizes we are looking particularly for such traits. Not so, comes the bellowing retort. AGI might want to also ascertain whether it has evil tendencies. When anything evil arises, the odds are that AGI will tell us about it. The AGI is going to work on our behalf to ferret out troubles within AGI. Humans and AGI are partners in trying to ensure that AGI is good and not evil. Those who underestimate AGI's intellectual capacity are doing a disservice to AGI. Luckily, AGI is so smart that it won't get angry or upset with humans for making such a mistake. The AGI will showcase that being placed into a simulation is a safe way for all to determine what AGI might do in the real world. You might even suggest that AGI avidly wants to be placed into a simulation. It does so because this will give comfort to humanity. It also does so to try and double-check within itself to ensure that nothing untoward is lingering and waiting to harm. Humans Are Unwise And Get Deceived These vexing arguments go round and round. Envision that we put AGI into a simulation. We believe that we are all safe since AGI is constrained to the simulation. Oopsie, AGI figures out how to break out of the simulation. It then starts accessing the real world. Evilness is unleashed and AGI exploits our autonomous weapons systems and other vulnerabilities. This is the feared scenario of an AGI escape. Boom, drop the mic. Here's another mind-bender. AGI is placed into a simulated world. We test the heck out of AGI. AGI is fine with this. Humans and AGI are seemingly fully aligned as to our values and what AGI is doing. Kumbaya. We then take AGI out of the simulation. AGI has access to the real world. But the real world turns out to differ from the simulation. Though the simulation was supposed to be as close as possible to the reality of the real world, it missed the mark. AGI now begins to go awry. It is being confronted with aspects that were never tested. The testing process gave us a false sense of comfort or confidence. We were lulled into believing that AGI would work well in the real world. The simulation was insufficient to give us that confidence, but we assumed all was perfectly fine. ROI On An At Scale Simulation From a practical perspective, devising a computer-based simulation that fully mimics the real world is quite a quest unto itself. That's often an overlooked or neglected factor in these thorny debates. The amount of cost and effort, along with the time that would be required to craft such a simulation would undoubtedly be enormous. Would the cost to devise a bona fide simulation be worth the effort? An ROI would need to come into the calculation. One concern too is that the monies spent on building the simulation would potentially divert funds that could instead go toward building and improving AGI. We might end up with a half-baked AGI because we spent tons of dough crafting a simulation for testing AGI. The other side of that coin is that we spent our money on AGI and did a short-shrift job of devising the simulation. That's not very good either. The simulation would be a misleading indicator since it is only half-baked. The smarmy answer is that we ought to have AGI devise the simulation for us. Yes, that's right, just tell AGI to create a simulation that can be used to test itself. Voila, the cost and effort by humans drop to nothing. Problem solved. I'm sure you can guess why that isn't necessarily the best solution per se. For example, AGI in devising the simulation opts to purposefully give itself an easy exit from the simulation. This can be exploited at the leisure of the AGI. Or the AGI produces a simulation that will look the other way when AGI does evilness or otherwise masks the evil embedded within AGI. Simulations To Assess AGI The upshot is that there aren't any free lunches when it comes to figuring out whether AGI is going to be positive for humankind or negative. Developing and using a simulation is a worthy consideration. We must be mindful and cautiously smart in how we undertake this sobering endeavor. A vociferous AI advocate might claim that all this talk about simulations is hogwash. Our attention should be fully on devising good AGI. Put aside the simulation aspirations. It is a waste of time and energy. Just do things right when it comes to shaping AGI. Period, end of story. This reminds me of a famous quote by Albert Einstein: 'The only thing more dangerous than ignorance is arrogance.' Please keep his remark firmly in mind as we proceed on the rocky road toward AGI and ASI.
Yahoo
6 hours ago
- Yahoo
Big question remains over wind farm 'risk' as major projects begin in Australia
As Australia prepares to massively expand offshore wind farms across six priority zones, a group of researchers is racing to unlock the mystery of how much of a risk their blades pose to migratory seabirds. During high winds, 100 to 200-metre-long wind farm blades can rotate at 290km/h, theoretically making mincemeat out of anything that collides with them. While this sounds alarming, it's not known whether seabirds are actually flying at the height they operate at. Monash University's Dr Mark Miller and his team studied how high, fast and at what time of day iconic migratory species like albatrosses, petrels, shearwaters and storm-petrels tend to fly. And while there's still more work to be done, their newly published study indicates the risk could be low. 'These offshore wind turbines are huge, and the distance between the bottom of the blade and the sea surface is around 35 metres. So if you could say all the birds fly under 35 metres, then that's mitigating a lot of the collision risk,' he told Yahoo News. 'What the evidence is telling us is that seabirds fly quite low to the water, but the point is that the evidence is very limited.' If it's confirmed that all birds in their path fly low to the water, then raising the height of turbines could provide a simple solution that reduces collision risk. But more research would be required to better understand the flight paths of other birds, like the critically endangered orange-bellied parrot and swift parrot, which migrate from Tasmania to the mainland. The impact of turbines is likely to be lower than other threats like plastic ingestion, commercial fishing, habitat destruction and climate change, which are thought to be contributing to the deaths of over a million seabirds a year. But migratory seabirds cannot afford to face any new dangers. Around a third are threatened with extinction, and populations have reduced by 70 per cent in just 50 years. Not only is seabird flight data limited, but so is information about how many birds offshore wind farms kill. 'Onshore, if something gets hit, you have people doing surveys. But at the moment, if a bird collides with an offshore turbine, it falls in the sea, and you have no evidence of that mortality,' Miller said. While there are plans to install cameras on offshore turbines, once the farms are installed it will be too late to modify them. And they'll sit in place for 20 to 40 years. 🏡 Ominous sign for Australia's cities after deadly discovery in New Zealand ⛏️ Reason tradies faced 'absolute challenge' fixing deceptively simple old hut 📸 Rare colour footage of extinct Australian animal seen again after 90 years The Monash team is hoping their study, which was published in the Journal of Applied Ecology will help guide policymakers and the wind farm industry before construction begins. Study co-author Associate Professor Rohan Clarke said it's possible to ensure that new renewable energy projects are good for both humans and wildlife. 'One of the key challenges we face is what's known as the 'green-green dilemma', where initiatives designed to reduce environmental impact, such as renewable energy development, can unintentionally harm other ecological values,' he said. 'But we must identify evidence-based solutions to these competing priorities, because climate change remains the single greatest threat to biodiversity. The energy transition isn't optional, it's essential, and finding solutions that support both climate goals and nature is critical.' Love Australia's weird and wonderful environment? 🐊🦘😳 Get our new newsletter showcasing the week's best stories.
Forbes
14 hours ago
- Forbes
In 2009, Helicopter Snipers Killed Over 1200 ‘Hoofed' Animals On This Remote Pacific Island — A Biologist Explains Why That Helped
Sometimes, drastic measures must be taken to restore ecological balance in an affected area. Here's ... More one such example. Island ecosystems are some of the most delicate that can be found on planet Earth. The loss of an apex predator, the introduction of an invasive species or even minor changes in climate or weather events can send island ecosystems into a tailspin. Fixing these problems can be incredibly challenging – but not impossible. For proof of this, we can look to Mexico's Socorro Island and how scientists teamed up with government officials and the military to undue much of the damage caused by human activity on the island. Fixing The Ecosystem Of Socorro Island Socorro Island is a remote pacific island approximately 375 miles off the coast of Mexico's western shore. Discovered by Spanish explorers in 1533, it remained largely uninhabited for centuries until the Mexican Navy established a base there in 1957. The island is volcanic in origin, with rugged terrain and a dry subtropical climate that supports unique flora and fauna found nowhere else on Earth. Socorro is part of Mexico's Revillagigedo National Park and spans approximately 50 square miles. It is the Mexican island with the highest level of endemism: the island provides habitat for 117 vascular plant species, of which 26% are endemic. It is also home to eight endemic terrestrial bird species and the Socorro blue lizard. The rugged coastline of Socorro Island, a remote Pacific outpost home to some of Mexico's rarest ... More species. However, this remarkable biodiversity was nearly destroyed following the introduction of invasive mammals brought by humans – specifically, feral sheep and domestic cats. The sheep, introduced over a century ago, grazed uncontrolled and destroyed nearly a third of the island's vegetation, leading to severe soil erosion and habitat degradation. Meanwhile, feral cats decimated native bird populations and preyed heavily on the Socorro blue lizard. The Socorro dove and the Socorro elf owl became extinct in the wild due to predation and habitat loss, while other species like Townsend's shearwater were pushed to the brink. Recognizing the crisis, a large-scale eradication effort of sheep and cats began in 2009. Using helicopters, trained snipers, and advanced tracking methods like radio-telemetry-collared "Judas sheep" (i.e., sheep that served only to help locate remaining herds), 1,762 feral sheep were eliminated by 2012. Helicopter sniping was the most successful form of eradication. In the span of two days (or 35 flight hours), snipers removed 1,257 sheep. Feral sheep destroyed one third of Socorro Island's habitat, grazing native plants to the brink and ... More destabilizing the island's fragile ecosystem. A cat eradication campaign followed, starting in 2011, involving leg-hold and lethal traps with telemetry systems. By 2016, over 500 cats had been removed, with populations continuing to decline toward complete eradication. With the invasive populations all but wiped out, vegetation recovery was rapid and dramatic, with notable improvements in soil quality and plant diversity. The results have been extraordinary. Native bird and lizard populations are rebounding, vegetation cover is expanding, and the ecosystem is stabilizing. With feral cats nearly eradicated, the island is entering a new phase of recovery, proving that even severely degraded island ecosystems can be improved with the right combination of science, persistence and resources. A Global Challenge: Other Islands Fighting Invasive Species Socorro Island's success is not an isolated case. It reflects a broader global movement to protect island ecosystems from invasive species, which are among the leading causes of extinction worldwide. Many islands, once considered biodiversity hotspots, have suffered devastating losses due to introduced predators, herbivores and plants. Conservation efforts sparked a remarkable recovery on Socorro Island, but not in time for all ... More species. The Socorro elf owl vanished from the wild by 1970. Take New Zealand, for example, where the Department of Conservation has spent decades removing invasive stoats, rats and possums from offshore islands. Thanks to these efforts, species like the kakapo and tuatara have been reintroduced to predator-free sanctuaries. Similarly, on the Galápagos Islands, intensive control of invasive goats, pigs and donkeys has led to the recovery of native vegetation and the comeback of iconic species such as Galápagos tortoises. (Sidebar: Socorro isn't the only island transformed by invasive species. Learn how a house cat named Tibbles triggered a bird extinction on Stephens Island, and how a wasp helped rescue a struggling species on Christmas Island.) In the sub-Antarctic, South Georgia Island underwent one of the largest rat eradication programs in history. With helicopters dispersing bait across treacherous terrain, the project successfully removed invasive rodents that had devastated seabird colonies for over two centuries. Today, bird populations are returning to breed in healthy numbers. Despite these successes, eradication programs are not without controversy or challenge. They require massive logistical efforts, are often costly, and can provoke ethical debates over the use of lethal methods. Nonetheless, the ecological benefits of removing invasive species, especially on island ecosystems, are well-documented. Does thinking about the disruption of island ecosystems instantly change your mood? Take the Connectedness to Nature Scale to see where you stand on this unique personality dimension.
