cortical geometer

Joined October 2016
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10 Dec 2025
I am deeply excited to share that I will be joining @AsteraInstitute to start a new effort to understand how the brain generates consciousness and intelligence.
We’re launching Astera Neuro, a new neuroscience research effort led by @doristsao as Chief Scientist. Our aim is to unravel a profound scientific mystery: how the brain transforms sensory inputs into conscious experience. Advancing this work could illuminate the computational principles that drive perception and cognition and inspire approaches for neuroscience-informed AI research, potentially generating new pathways to AGI. Astera will support this work with $600M over the next decade. Read more: astera.org/neuroscientist-do…
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Doris Tsao retweeted
Triple-N dataset published in Nature Neuroscience 🧠Combined fMRI functional mapping dense NHP neural recordings to unpack primate visual encoding of natural stimuli. Open dataset available for the field. Grateful to all collaborators.
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Doris Tsao retweeted
The Lin Lab is hiring! We're seeking motivated postdocs for projects on voltage imaging and optogenetics in the brain. If you're excited about using new methods to undersatand and correct brain diseases, working together with other neuroscience labs at Stanford, drop us a line!
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One thing great stories share is that they work on multiple levels. This is definitely that: mars, purple paint, and how to become a better scientist 🤩
Space science can have surprising impacts here on Earth. In this essay, @erika_alden_d explores how work on terraforming Mars led to real-world applications — and why pushing scientific boundaries matters. Read more: open.substack.com/pub/erikaa…
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Doris Tsao retweeted
In systems neuroscience, this is simply not the case. Paradigms are challenged and updated all the time.
Some branches of neuroscience (and science in general) are unlikely to see real progress for a long time. This stagnation stems from an academic echo chamber that very effectively silences dissent. young researchers introducing new ideas are often marginalized or driven out before they can establish themselves. There must be quite a few of these people who left academia this way and are now working in industry. The current institutional framework simply won't fund or validate anyone bold enough to challenge entrenched ideas. It's a conformist paradise gated by tenure. BTW these stagnant areas tend to have dominant senior people who have never been wrong and shall remain "authorities" forever.
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Doris Tsao retweeted
Just a reminder of @AsteraInstitute's open essay competition about identifying and overcoming scientific bottlenecks. Deadline for entries is May 1!
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Doris Tsao retweeted
Great to see this on X. This is something I created during my PhD time 20 years ago.
This is a healing grid by Japanese artist Ryota Kanai. If you stare at the center, the irregularities start to heal themselves because your brain strongly prefers to see regular patterns.
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This is the strongest ephys evidence so far for a generative model in the brain that I know of. Congratulations @WadiaVarun! Wonderful collaboration with @UeliRutishauser on science that could only be done in humans. And please check out Fig. 5FG. This is new since biorxiv and really surprised me: the mean response to imagery and viewing is actually the same & there are many cells that respond only during imagery--challenging the idea that signal strength is what distinguishes reality from imagination.
1/8 Our preprint is now a peer-reviewed paper :) Big thanks to our reviewers who pushed us to examine our results more carefully and Olivier Wyart (headquarter.paris/) for the exquisite visual. science.org/doi/10.1126/scie…
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I will be giving the Martin Meyerson Faculty Research Lecture tomorrow 4/8 at 4 pm at UC Berkeley. This is a public lecture open to all. Revised title is: "Representing the visual world: from faces to consciousness" facultylectures.berkeley.edu…

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Doris Tsao retweeted
The brain uses 20% of your body's energy with 2% of its mass. Implant an electrode, and you sever the blood vessels delivering that energy. Nearby neurons don't die. They go silent. They're rationing fuel.
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"You cannot align a system to human values without fundamentally understanding how those values are implemented." -James Fickel et al. "The existence of experience is the universe's sole source of value." -Max Hodak If the above statements are true (and I think they are), it's critical to understand how experience, i.e., consciousness, is implemented.
Towards Magnanimous AGI Before we build extremely powerful alien minds, we must understand our own minds and the mechanisms behind prosocial behavior. After years of investigating brain-based AI safety, here’s what we found and the teams we're backing: blog.amaranth.foundation/p/t…
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We show face patches implement the following code through recurrent dynamics: Detect face If (face found) Discriminate face else Continue to detect face IMHO, our paper conclusively resolves a debate that has raged since I was a graduate student, about whether face patches are specialized for processing faces or not. It turns out domain-general folks were right early on, domain-specific folks were right later in the response. So proud of @Yuelin_Shi and the entire team!
Our paper is now out! nature.com/articles/s41586-0… A big question: 1) Is IT cortex well described as a general-purpose feedforward DNN? OR 2) Are face patches genuinely specialized for processing faces? Read on to find out the answer. (1/N)
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Apr 19 is nearing...please apply to become an Astera Resident if you are excited by the prospect of spending 12-18 months diving deep & building at the frontier of neuroscience/AI/robotics and meta science. Within the realm of neuro, we welcome all ideas from tools to theory. Crazy ambitious is good. I guarantee you will find Astera a one-of-a-kind ecosystem--it's paradise for a certain kind of person.
Come be my colleague! Apply to the Astera Fellows program! You will get a great salary AND very generous resources to start your own independent research program. A core area of interest is neuroscience & AI. Please RT
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My course on consciousness is now online: six 90´ lectures featuring both history and recent experimental results on ignition, P3b, working memory, neural manifolds… unpublished results too. tinyurl.com/cz9yb4z3

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Huge gratitude to Valentina Emiliani @EmilianiLab, Eirini Papagiakoumou, and the incredible lecturers and TAs of the course on “All-Optical control of brain functioning with Optogenetics and multi-photon microscopy” here in Paris. The class took us on a deep dive into 2p imaging and holography--starting from the basics of how a lens works (I did not know a lens computes a fourier transform!), and progressing to advanced methods including 3d holography with temporal focusing, voltage imaging, tricks to minimize heating, etc. We got hands-on experience though an amazing set of labs (including closed loop feedback holographic stimulation through a GRIN lens in a freely moving mouse). The entire experience was incredible, and I highly recommend for anyone interested in this frontier of neurotechnology. It was so much fun to be a student again!
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Doris Tsao retweeted
TL;DR: “A lie can travel half way around the world while the truth is putting on its shoes.” 😊
Replying to @KennethHayworth
So, some people are asking me why this EON fly video doesn’t show real ‘uploading’ since it does simulate a real connectome. The most important reason is that the functional parameters that define the dynamic behavior of individual neuron and synapse types in the connectome are unknown. Instead, they used an existing model (nature.com/articles/s41586-0…) which substitutes these with guessed parameters and grossly simplified dynamics. As made clear in that older paper, these are not sufficient to recreate the activity patterns that would be seen in the real fly. The simplified dynamics would not, for example, be able to choreograph the timing of leg muscles during walking or grooming, or the dynamics of the compass neurons encoding the fly’s heading direction, or the myriad other neuronal dynamics that make up the fly ‘mind’. So not an ‘upload’ by any reasonable definition. In fact, the simplified dynamics they used have only been demonstrated to approximate gross correlations along major sensory-motor pathways for a handful of neurons. For example: activating a sugar sensing neuron causes gross downstream activation that elevates the activity of feeding neurons. It is this handful of very, very crude and basic correlations in the simulated connectome that are being used to drive the EON simulated fly. If they had said that from the start, then I would have had no issue. But instead, they made the bold claim that they had “uploaded a fly” and presented a video of said fly walking over a landscape with highly articulate legs, visually navigating through the terrain to a food source, grooming its antenna with eerily fly-like leg motions, etc. Any reasonable layperson would assume that these visually exciting articulations are the ones being controlled by the simulated brain’s dynamics instead of being faked by computational add-on routines. There are now many secondary reports of this on YouTube and all of them seem to make this reasonable assumption (e.g. youtube.com/shorts/Z7NNP1ZI0…). And who could blame them? Many neuroscientists also made that assumption before EON started to spell out what was really behind the video millions of views and over a day later. To make clearer just how misleading EON Systems’ video is and how outlandishly laughable their ‘uploading’ claim is, below is an imagined back-and-forth discussion between a [Reasonable Layperson] and a [Neuroscientist] trying to explain to them what is really behind the video: [Reasonable Layperson] “Look at the complicated leg motions as the fly walks… the timing of all those dozens of individual muscles being controlled by the dynamics of the simulated neurons… and they say that they used no reinforcement learning to tune parameters, just the connectome… that is really impressive!” [Neuroscientist] “Well actually no… those leg movements are actually coming from a program unrelated to the connectome. The connectome used didn’t even include the central pattern generator circuits in the ventral nerve cord responsible for controlling leg muscles.” [Reasonable Layperson] “Oh… so in what sense is the simulated connectome controlling walking?” [Neuroscientist] “It looks like they just found a few neurons in the brain connectome that are correlated with right/left/forward motion and used these to ‘steer’ the pretend walking routine.” [Reasonable Layperson] “Oh… But the activations of those ‘steering’ neurons are reflecting the complicated dynamics of tens of thousands of simulated neurons in the fly visual system as it moves through the virtual world, avoiding objects and heading toward its visual goal, right?” [Neuroscientist] “Well actually no … The visual system and virtual world are essentially ‘decoration’… the flashing dynamic neural responses as the fly moves through the virtual environment are designed to give the viewer the impression that the simulated fly is actually seeing the world and making walking decisions based on those visual responses. But, in fact, they could turn off the lights and the fly would behave identically.” [Reasonable Layperson] “Oh… so how does the fly walk toward the food then?” [Neuroscientist] “Well… it looks like they simply imposed an odor gradient in the virtual environment that is centered on the virtual food. The fly has two sets of odor receptors (right and left) that sense this gradient and the activation of these in the connectome is correlated with the activation of the ‘steering’ neurons. So if the left odor neuron activates more than the right then the fly steers left.” [Reasonable Layperson] “Oh… so it is like one of those toy cars that moves toward a light because it has right and left light sensors cross-connected to right and left motors… Gee, I thought a fly was more complicated than that.” [Neuroscientist] “Well actually a real fly is. Real flies have dozens of behavioral states that allow intelligent behavior in a complicated visual and sensory environment. In fact, a real fly contains a set of neurons which act as an internal compass updated by the visual environment and the fly’s walking.” [Reasonable Layperson] “Oh… and their connectome has those internal compass neurons?” [Neuroscientist] “Yes. They used the full brain connectome that contains those compass neurons.” [Reasonable Layperson] “...And their compass neuron activations are tracking the visual environment just like in the real fly?” [Neuroscientist] “Oh sweet summer child… those compass neurons exist in their connectome simulation, but no one knows enough about their functional parameters (synaptic weights, time constants, etc.) to simulate them accurately. They light up in pretty patterns totally unrelated to how they would in a real fly walking through that visual world.” [Reasonable Layperson] “Oh… and the complicated leg movements it shows during antenna grooming… is that also just a faked recording?” [Neuroscientist] “Yes. All the complicated leg motions shown during grooming are faked by a hard-coded program. But they turn that fake routine on or off by looking at some neurons in the connectome that are correlated with actual grooming behavior triggered by dust accumulation on the antenna… well really they fake the dust too by just activating a set of neurons after a delay.” [Reasonable Layperson] “And what did EON Systems do? Did they acquire the connectome? Did they determine the neurotransmitter types? Did they do the calcium imaging experiments to determine the steering and grooming neurons? Did they make the mechanical fly model?” [Neuroscientist] “No. Those were all done by real labs who were kind enough to carefully write up their results in open journals and to post their results and code openly online…. It looks like Eon Systems just took their code and put it together with a virtual environment designed specifically to trick viewers by triggering behaviors in misleading ways.”
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Love the name of their device: Neo ("neural electronic opportunity") ichgcp.net/clinical-trials-r…

First for the world, not just China. This is the first time any national medical regulator has granted market approval to a fully implanted BCI.
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Doris Tsao retweeted
I'm personally v excited about this competition. Hope it amplifies critical dialogue among scientists into a more open and constructive space that funders/policy makers help enable experimentation around. Metascience should involve more scientists! asterainstitute.substack.com…

Replying to @AsteraInstitute
And finally scientists -- share your hypotheses for structural or systemic bottlenecks that we could run experiments on. New essay competition dropping today to give you a voice: asterainstitute.substack.com…
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