David Segar

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David Segar

David Segar

@DaveSegar

medical director @Nudge. previously neurosurgeon/scientist @NeurosurgUCSF @MGBNeurosurgery

San Francisco, CA Katılım Mart 2011
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David Segar
David Segar@DaveSegar·
The first time I understood the impact of neuromodulation was while witnessing a deep brain stimulation surgery during my first year of medical school. What stuck with me--more than anything else--was the way the patient's face lit up when her symptoms disappeared. Surgical treatments can be world-changing, but they won't reach everyone. Imagine you could safely target those same parts of the brain, but without surgery. At @nudge, we're doing just that, by building non-invasive brain interfaces to deliver life-changing treatments to millions of people. Excited to see where we can take this.
Nudge@nudge

Half the world will experience a brain disorder in their lifetime. At @nudge, we're building brain interfaces that are safe, precise, and non-invasive to solve that problem. We've raised a $100M Series A led by @ThriveCapital and Greenoaks to go faster. We're hiring. Join us.

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Derya Unutmaz, MD
Derya Unutmaz, MD@DeryaTR_·
Until a few hours ago, creating this kind of scientific image would have required at least an hour of professional work. Now, with NanoBanana Pro, it only takes a simple prompt & less than 30 seconds! Prompt: “Describe in an illustration the events for a cytotoxic T cell recognizing & killing a cancer cell.”
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Sam Altman
Sam Altman@sama·
This is exciting; I expect we are going to see a lot more things like this and it will be one of the most important impacts of AI. Congrats to the Future House team. edisonscientific.com/articles/annou…
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Sam Rodriques
Sam Rodriques@SGRodriques·
@sama Thanks!! Anyone who is interested can try Kosmos for themselves here: platform.edisonscientific.com All possible in large part due to the amazing work you guys have been doing at OpenAI. Keep it up, and the next few years are going to be awesome.
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Sam Rodriques
Sam Rodriques@SGRodriques·
Seen on a friend's company slack...
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Patrick Collison
Patrick Collison@patrickc·
An interesting trend we're noticing at Stripe: US startups are pulling ahead of their peers elsewhere. These charts show averaged revenue growth for software startups in each location. US startups typically grow somewhat faster than those elsewhere. However, since mid-2023, US companies have accelerated a lot. Interestingly, this is not just because of AI startups: if we strip those out, there's still a big divergence. Our leading hypothesis is that US startups (even those that aren't AI companies as such) are adopting new technologies (AI, stablecoins, etc.) faster than companies elsewhere. (This pattern of faster adoption among US companies was also seen with the internet itself.) Whatever the cause, the pattern is striking. [Methodological note: this pattern appears to hold beyond Europe as well.]
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Jacques Carolan
Jacques Carolan@JacquesCarolan·
such incredible news: for the entire @uclh team, uk neurotech and most importantly for paul and the folks in the future who will benefit from this technology. huge congratulations to everyone involved 🚀
Neuralink@neuralink

🇬🇧 We’re excited to announce our first participant in the UK! Paul, who is paralyzed due to motor neuron disease, received his Neuralink implant at @uclh earlier this month and was able to control a computer with his thoughts just hours after surgery.

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Sam Rodriques
Sam Rodriques@SGRodriques·
Cutting PhD spots is not the way for a country to win in a more competitive world.
Patrick Hsu@pdhsu

an absolute shame. @harvard cutting PhD admissions "The Organismic and Evolutionary Biology department will shrink its class size by roughly 75 percent to three new Ph.D. students [...] Molecular and Cellular Biology will reduce its figure to four new students, and Chemistry and Chemical Biology will go down to four or five admits" thecrimson.com/article/2025/1…

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Science Corporation
Science Corporation@ScienceCorp_·
@BBCNews followed one of the patients at @Moorfields in London who participated in our landmark clinical trial of PRIMA. She began losing her sight more than three decades ago due to age-related macular degeneration. Now she can read again for the first time in years. @NEJM published the results of this trial yesterday in a new peer-reviewed original paper.
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Christopher Mims 🤌
This is fascinating! The goal has always been eliminate road deaths. If this holds up as Waymo scales, could be truly huge.
Dr. Jon Slotkin@slotkinjr

As a neurosurgeon I care a lot about road safety. By now you’ve probably seen @Waymo’s stunning safety results (like 91% fewer serious crashes). But they didn’t just publish data headlines. They released the raw CSV files and data dictionaries. I did a much deeper analysis. A fascinating story emerges when you analyze how they’re achieving this. This isn’t incremental improvement - it’s categorical. We’re looking at the potential elimination of traffic deaths as a leading cause of mortality. The intersection breakthrough: Waymo has essentially solved intersection crashes, with 95% fewer injury incidents than human drivers in the same locations. That’s transforming the deadliest driving scenario. The national math: If every US vehicle performed like Waymo, we’d prevent 33,000-39,000 deaths annually and save $0.9-1.25 trillion in societal costs. Even partial adoption at 27% would save ~10,000 lives per year. In terms of magnitude, this would be the equivalent of eliminating every pedestrian death nationally in a year. The physics signature: Here’s what fascinates me: 47% of Waymo’s contacts involve less than 1 mph delta-V. They’re not just avoiding crashes; they’re converting unavoidable incidents into gentle bumps. It’s like having physics itself on your side. We’re not talking about marginal safety gains. The data represents a fundamental shift from harm reduction to harm prevention. The methodology matters: I used their dynamic geographic benchmarks (comparing like-for-like road conditions) and verified the findings hold across San Francisco, Phoenix, LA, and Austin. The safety advantage actually increases in more complex urban environments. Link to raw data below…. Notes on my approach: Analysis based on 96 million miles of Waymo Rider-Only (RO) data through June 2025, utilizing Waymo's dynamic geographic benchmarks to compare Waymo Driver performance against human drivers under similar road conditions and operational design domains. The projections for national impact (deaths prevented, societal costs) involve several assumptions. Given Waymo's zero reported fatalities, the direct serious injury reductions were mapped to national fatality statistics using established NHTSA-derived ratios that correlate serious injury crash rates with fatality rates. This extrapolation assumes that Waymo's observed serious injury prevention capability would translate proportionally to fatality prevention. Societal cost savings are estimated by applying average per-fatality and per-injury economic costs (e.g., medical, lost productivity, quality of life) as published by NHTSA, scaling these national averages to the projected number of avoided fatalities and injuries based on Waymo's safety performance. These figures represent the potential annual impact if the Waymo Driver's safety profile were widely integrated into the national fleet. @ethanteicher

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Bryan Johnson
Bryan Johnson@bryan_johnson·
This is big. OpenAI and Retro used a custom model to make cellular reprogramming into stem cells ~50× better, faster, and safer. Similar Wright brothers’ glider to a jet engine overnight. We may be the first generation who won't die. Let's take a look at what they did. 🧵
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Jacques Carolan
Jacques Carolan@JacquesCarolan·
I’ve been thinking a lot about how we scale neurotech. Current approaches (e.g. DBS for PD) aren’t meeting the need. Emerging ones may fare even worse. That’s why I’m scoping an @ARIA_research programme to develop neurotech built for scale. Check out my post +share feedback!👇
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Nick Wray
Nick Wray@Telepath_8·
Hello World! My name Nick Wray and I am P8 (Telepath8) in the Neuralink trials! It has been such an honor and privilege to be a pioneer in the world of cybernetic enhancement. Today is day 3 of using the N1 Telepathy chip and I haven’t had this level of digital autonomy in years. The precision and speed of control out of the box has been astounding and liberating. I can’t wait to learn to play the drums again! I hope to contribute extensively to the product and user experience going forward. I’m very excited about the possibilities for the future in my lifetime and beyond. To be able to create again is life changing. I hope to be one of the first people to hold my own with AI. It’s still faster than me, for now, but one day soon I may be collaborating with it, or creating with it in ways previously unimagined. “Do not try to bend the spoon. That’s impossible. Instead, only try to realize the truth: there is no spoon.” Now replace spoon with trackpad, gamepad, or mouse and here we are! Since the first time I read Johnny Mnemonic and Neuromancer by William Gibson, BCI has been the dream. After decades of fantasy, I’m actually a Console Cowboy the likes of Henry Case. This is both fantastic and profound. In becoming a member of The Miami Project to Cure Paralysis, I have the opportunities to further research into finding and fine tuning possible solutions to this age old malady AND to further research on human-machine symbiosis and working beyond the limitations of my physical body. On the very first day using my BCI, I was afforded a glimpse, the slightest whiff, of the capabilities I will achieve with practice and it is so far beyond anything I could have dreamt of as an able bodied individual. It’s not lost on me that without ALS, I would never have been a candidate for this study. I sincerely believe that if ALS is the price of admission to an opportunity of this magnitude, you pay it; gladly, willingly, and without hesitation. I would do it all again to end up right where I am, right where I’m supposed to be. #Neuralink #BCI #Cyberpunk
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Neil Parikh
Neil Parikh@neilparikh·
They said it couldn't be done. They said it *shouldn't* be done. We tried anyways. Today we're launching Ash, the first AI designed for therapy, and announcing $93M in funding from @radicalventures @ForerunnerVC @a16z @felicis @trailmixvc @joinsequel and many more. We've had 50k people using it, with pretty transformative results. Here's my co-founder @danielreidcahn telling our story. Link to Ash below.
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