Steven Ryu
@stevencryu.bsky.social
MD/PhD Student at Washington University at St. Louis. Systems neuroscience, psychiatry, and metacognition w/ Kepecs Lab.
Reposted by Steven Ryu
“Our findings challenge the conventional focus on low-dimensional coding subspaces as a sufficient framework for understanding neural computations, demonstrating that dimensions previously considered task-irrelevant and accounting for little variance can have a critical role in driving behavior.”
Neural dynamics outside task-coding dimensions drive decision trajectories through transient amplification
Most behaviors involve neural dynamics in high-dimensional activity spaces. A common approach is to extract dimensions that capture task-related variability, such as those separating stimuli or choice...
www.biorxiv.org
November 23, 2025 at 1:38 PM
“Our findings challenge the conventional focus on low-dimensional coding subspaces as a sufficient framework for understanding neural computations, demonstrating that dimensions previously considered task-irrelevant and accounting for little variance can have a critical role in driving behavior.”
Reposted by Steven Ryu
Thrilled that our paper is out today in Nature!
www.nature.com/articles/s4...
www.nature.com/articles/s4...
Sensory expectations shape neural population dynamics in motor circuits
Nature - Experiments with human volunteers and macaques show that expectations produced by probabilistic cueing of future sensory inputs shape motor circuit dynamics in order to increase the...
www.nature.com
October 29, 2025 at 4:11 PM
Thrilled that our paper is out today in Nature!
www.nature.com/articles/s4...
www.nature.com/articles/s4...
Reposted by Steven Ryu
Want to make publication-ready figures come straight from Python without having to do any manual editing? Are you fed up with axes labels being unreadable during your presentations? Follow this short tutorial including code examples! 👇🧵
October 16, 2025 at 8:26 AM
Want to make publication-ready figures come straight from Python without having to do any manual editing? Are you fed up with axes labels being unreadable during your presentations? Follow this short tutorial including code examples! 👇🧵
Reposted by Steven Ryu
It continues to be weird to me that adult CNS neurons have a single, nonmotile cilium just hanging out, maybe acting as a site for receptor expression. Like a little extra antenna that we all just ignore in our drawings of neurons. www.cell.com/neuron/fullt...
pmc.ncbi.nlm.nih.gov/articles/PMC...
pmc.ncbi.nlm.nih.gov/articles/PMC...
Primary Cilia in the Developing and Mature Brain
Primary cilia emerge as key regulators of development, neurogenesis, and signaling
in the mammalian brain. Guemez-Gamboa et al. review the status, genetic basis, potential,
controversies, and unanswer...
www.cell.com
September 29, 2025 at 2:46 AM
It continues to be weird to me that adult CNS neurons have a single, nonmotile cilium just hanging out, maybe acting as a site for receptor expression. Like a little extra antenna that we all just ignore in our drawings of neurons. www.cell.com/neuron/fullt...
pmc.ncbi.nlm.nih.gov/articles/PMC...
pmc.ncbi.nlm.nih.gov/articles/PMC...
Reposted by Steven Ryu
I’m super excited to finally put my recent work with @behrenstimb.bsky.social on bioRxiv, where we develop a new mechanistic theory of how PFC structures adaptive behaviour using attractor dynamics in space and time!
www.biorxiv.org/content/10.1...
www.biorxiv.org/content/10.1...
September 24, 2025 at 12:04 PM
I’m super excited to finally put my recent work with @behrenstimb.bsky.social on bioRxiv, where we develop a new mechanistic theory of how PFC structures adaptive behaviour using attractor dynamics in space and time!
www.biorxiv.org/content/10.1...
www.biorxiv.org/content/10.1...
Reposted by Steven Ryu
What happens in your brain when you make up your mind?
Postdoc (soon faculty at U. of Utah) @thomas-zhihao-luo.bsky.social and ex-grad student (now Shanahan Fellow at Allen Institute) @timkimd.bsky.social have some answers in this new paper out in Nature!
www.nature.com/articles/s41...
🧵 1/6
Postdoc (soon faculty at U. of Utah) @thomas-zhihao-luo.bsky.social and ex-grad student (now Shanahan Fellow at Allen Institute) @timkimd.bsky.social have some answers in this new paper out in Nature!
www.nature.com/articles/s41...
🧵 1/6
September 19, 2025 at 1:01 PM
What happens in your brain when you make up your mind?
Postdoc (soon faculty at U. of Utah) @thomas-zhihao-luo.bsky.social and ex-grad student (now Shanahan Fellow at Allen Institute) @timkimd.bsky.social have some answers in this new paper out in Nature!
www.nature.com/articles/s41...
🧵 1/6
Postdoc (soon faculty at U. of Utah) @thomas-zhihao-luo.bsky.social and ex-grad student (now Shanahan Fellow at Allen Institute) @timkimd.bsky.social have some answers in this new paper out in Nature!
www.nature.com/articles/s41...
🧵 1/6
Reposted by Steven Ryu
📢 NEW PREPRINT 📢 We show a metacognitive paradox (not blanket deficit!) in OCD: confidence is persistently lower, but fluctuations track evidence more tightly and are nearer Bayes-optimal.
www.researchsquare.com/article/rs-7...
🧵👇
www.researchsquare.com/article/rs-7...
🧵👇
The metacognitive paradox of OCD: confidence is globally reduced but shows increased
sensitivity to local evidence
Confidence is a critical metacognitive signal that guides performance. Biases in confidence, such
as excessive doubt, are hallmark features of mental health disorders, especially obsessive-
compulsive...
www.researchsquare.com
September 16, 2025 at 10:01 PM
📢 NEW PREPRINT 📢 We show a metacognitive paradox (not blanket deficit!) in OCD: confidence is persistently lower, but fluctuations track evidence more tightly and are nearer Bayes-optimal.
www.researchsquare.com/article/rs-7...
🧵👇
www.researchsquare.com/article/rs-7...
🧵👇
Reposted by Steven Ryu
This is an incredible development for all types of conditions. Including neuromodulation for depression (like TMS) which is currently largely limited to the brain's surface whereas some of the most relevant bits of the mood network lie deep in the brain (subcallosal cingulate, insula ...).
Might focused ultrasound one day replace DBS?
UK Scientists built a 256-panel focused ultrasound helmet that can precisely target deep brain regions. Using theta-burst TUS, they stimulated the LGN and found visual cortex activity with effects lasting up to 40 minutes.
#neuroskyence #ultrasound
UK Scientists built a 256-panel focused ultrasound helmet that can precisely target deep brain regions. Using theta-burst TUS, they stimulated the LGN and found visual cortex activity with effects lasting up to 40 minutes.
#neuroskyence #ultrasound
Ultrasound system for precise neuromodulation of human deep brain circuits - Nature Communications
Modulating deep brain structure can lead to therapies for neurological conditions. Here, the authors show a transcranial ultrasound stimulation (TUS) system featuring a 256-element helmet-shaped trans...
www.nature.com
September 15, 2025 at 1:33 PM
This is an incredible development for all types of conditions. Including neuromodulation for depression (like TMS) which is currently largely limited to the brain's surface whereas some of the most relevant bits of the mood network lie deep in the brain (subcallosal cingulate, insula ...).
Reposted by Steven Ryu
Super excited to share the first cooperative foraging paradigm in freely interacting mouse pairs! Stable leader and follower roles emerge spontaneously and predict learning. Well-trained mice show stereotyped, role-specific “behavioral motifs” absent in naive animals (1/5)
doi.org/10.1101/2025...
doi.org/10.1101/2025...
September 4, 2025 at 2:21 PM
Super excited to share the first cooperative foraging paradigm in freely interacting mouse pairs! Stable leader and follower roles emerge spontaneously and predict learning. Well-trained mice show stereotyped, role-specific “behavioral motifs” absent in naive animals (1/5)
doi.org/10.1101/2025...
doi.org/10.1101/2025...
Reposted by Steven Ryu
My new essay for @thetransmitter.bsky.social. Why is understanding emotion so challenging? The debates around what counts as an "emotion" shed insight.
These disputes are multidimensional, principled and fascinating. Here, I unpack them.
www.thetransmitter.org/the-big-pict...
These disputes are multidimensional, principled and fascinating. Here, I unpack them.
www.thetransmitter.org/the-big-pict...
Emotion research has a communication conundrum
In 2025, the words we use to describe emotions matter, but their definitions are controversial. Here, I unpack the different positions in this space and the rationales behind them—and I invite 13…
www.thetransmitter.org
September 5, 2025 at 11:15 AM
My new essay for @thetransmitter.bsky.social. Why is understanding emotion so challenging? The debates around what counts as an "emotion" shed insight.
These disputes are multidimensional, principled and fascinating. Here, I unpack them.
www.thetransmitter.org/the-big-pict...
These disputes are multidimensional, principled and fascinating. Here, I unpack them.
www.thetransmitter.org/the-big-pict...
Reposted by Steven Ryu
𝗪𝗵𝗮𝘁 𝗺𝗼𝘁𝗶𝘃𝗮𝘁𝗲𝘀 𝗮𝗻𝗶𝗺𝗮𝗹𝘀 𝘁𝗼 𝗮𝗰𝘁, 𝘄𝗵𝗮𝘁 𝗶𝘀 𝗺𝗼𝘁𝗶𝘃𝗮𝘁𝗶𝗼𝗻?
What are the most developed frameworks of the brain basis of motivation?
Older ideas, new ideas, etc.
#neuroskyence
What are the most developed frameworks of the brain basis of motivation?
Older ideas, new ideas, etc.
#neuroskyence
August 8, 2025 at 7:57 PM
𝗪𝗵𝗮𝘁 𝗺𝗼𝘁𝗶𝘃𝗮𝘁𝗲𝘀 𝗮𝗻𝗶𝗺𝗮𝗹𝘀 𝘁𝗼 𝗮𝗰𝘁, 𝘄𝗵𝗮𝘁 𝗶𝘀 𝗺𝗼𝘁𝗶𝘃𝗮𝘁𝗶𝗼𝗻?
What are the most developed frameworks of the brain basis of motivation?
Older ideas, new ideas, etc.
#neuroskyence
What are the most developed frameworks of the brain basis of motivation?
Older ideas, new ideas, etc.
#neuroskyence
Reposted by Steven Ryu
I still get chills
Meet Mike
*30+ years severe depression
*first hospitalized @ 13y
*20 meds
*3 rounds of ECT
*2 near-fatal suicide attempts
Mike felt joy for the first time in decades after we turned on his new brain pacemaker or PACE
see videos, read paper, follow thread
doi.org/10.31234/osf...
Meet Mike
*30+ years severe depression
*first hospitalized @ 13y
*20 meds
*3 rounds of ECT
*2 near-fatal suicide attempts
Mike felt joy for the first time in decades after we turned on his new brain pacemaker or PACE
see videos, read paper, follow thread
doi.org/10.31234/osf...
August 10, 2025 at 6:23 PM
I still get chills
Meet Mike
*30+ years severe depression
*first hospitalized @ 13y
*20 meds
*3 rounds of ECT
*2 near-fatal suicide attempts
Mike felt joy for the first time in decades after we turned on his new brain pacemaker or PACE
see videos, read paper, follow thread
doi.org/10.31234/osf...
Meet Mike
*30+ years severe depression
*first hospitalized @ 13y
*20 meds
*3 rounds of ECT
*2 near-fatal suicide attempts
Mike felt joy for the first time in decades after we turned on his new brain pacemaker or PACE
see videos, read paper, follow thread
doi.org/10.31234/osf...
Reposted by Steven Ryu
Hung-tu Chen, Nicolas Tritsch, Matt van der Meer, and I have submitted a new preprint (doi.org/10.1101/2025...) in which we use simultaneous hippocampal ephys and ventral striatal (VS) fiber photometry to establish a link between sharp-wave ripples (SWRs) and VS dopamine (DA) in mice. (1/9)
Ventral Striatal Dopamine Increases following Hippocampal Sharp-Wave Ripples
Leading theories suggest that hippocampal replay drives offline learning through coupling with an internal teaching signal such as ventral striatal dopamine (DA); however, the relationship between hip...
www.biorxiv.org
August 4, 2025 at 6:30 PM
Hung-tu Chen, Nicolas Tritsch, Matt van der Meer, and I have submitted a new preprint (doi.org/10.1101/2025...) in which we use simultaneous hippocampal ephys and ventral striatal (VS) fiber photometry to establish a link between sharp-wave ripples (SWRs) and VS dopamine (DA) in mice. (1/9)
Reposted by Steven Ryu
We were asked to write a commentary on NeuroAI for Nat. Rev. Neuro. with Sadra Sadeh, so here it is: www.nature.com/articles/s41...
www.nature.com
August 8, 2025 at 10:31 AM
We were asked to write a commentary on NeuroAI for Nat. Rev. Neuro. with Sadra Sadeh, so here it is: www.nature.com/articles/s41...
Reposted by Steven Ryu
Will start my posts here with a preprint!
First preprint from my postdoctoral work—where we redefine and remap the isocortical efferent projectome through two foundational neurogenic mechanisms.
*
(1/5)
First preprint from my postdoctoral work—where we redefine and remap the isocortical efferent projectome through two foundational neurogenic mechanisms.
*
(1/5)
Distinct neurogenic pathways shape the diversification and mosaic organization of cortical output channels https://www.biorxiv.org/content/10.1101/2025.07.18.665624v1
July 25, 2025 at 10:45 AM
Will start my posts here with a preprint!
First preprint from my postdoctoral work—where we redefine and remap the isocortical efferent projectome through two foundational neurogenic mechanisms.
*
(1/5)
First preprint from my postdoctoral work—where we redefine and remap the isocortical efferent projectome through two foundational neurogenic mechanisms.
*
(1/5)
Reposted by Steven Ryu
1/ Mapping synaptic connectivity between individual neurons is extremely laborious. We developed BRISC, a new method that makes it possible to map inputs onto 100s of neurons in the same animal in a matter of weeks! Led by Alex Becalick and @antblot.bsky.social. 🧵
www.biorxiv.org/content/10.1...
www.biorxiv.org/content/10.1...
Barcoded Rabies In Situ Connectomics for high-throughput reconstruction of neural circuits
Sequencing of oligonucleotide barcodes holds promise as a high-throughput approach for reconstructing synaptic connectivity at scale. Rabies viruses can act as a vehicle for barcode transmission, than...
www.biorxiv.org
July 21, 2025 at 7:58 AM
1/ Mapping synaptic connectivity between individual neurons is extremely laborious. We developed BRISC, a new method that makes it possible to map inputs onto 100s of neurons in the same animal in a matter of weeks! Led by Alex Becalick and @antblot.bsky.social. 🧵
www.biorxiv.org/content/10.1...
www.biorxiv.org/content/10.1...
Reposted by Steven Ryu
Super excited to see this paper from Armin Lak & colleagues out! (I've seen @saxelab.bsky.social present it before.)
www.cell.com/cell/fulltex...
tl;dr: The learning trajectories that individual mice take correspond to different saddle points in a deep net's loss landscape.
🧠📈 🧪 #NeuroAI
www.cell.com/cell/fulltex...
tl;dr: The learning trajectories that individual mice take correspond to different saddle points in a deep net's loss landscape.
🧠📈 🧪 #NeuroAI
Dopamine encodes deep network teaching signals for individual learning trajectories
Longitudinal tracking of long-term learning behavior and striatal dopamine reveals
that dopamine teaching signals shape individually diverse yet systematic learning
trajectories, captured mathematical...
www.cell.com
July 10, 2025 at 6:29 PM
Super excited to see this paper from Armin Lak & colleagues out! (I've seen @saxelab.bsky.social present it before.)
www.cell.com/cell/fulltex...
tl;dr: The learning trajectories that individual mice take correspond to different saddle points in a deep net's loss landscape.
🧠📈 🧪 #NeuroAI
www.cell.com/cell/fulltex...
tl;dr: The learning trajectories that individual mice take correspond to different saddle points in a deep net's loss landscape.
🧠📈 🧪 #NeuroAI
Reposted by Steven Ryu
1/3) This may be a very important paper, it suggests that there are no prediction error encoding neurons in sensory areas of cortex:
www.biorxiv.org/content/10.1...
I personally am a big fan of the idea that cortical regions (allo and neo) are doing sequence prediction.
But...
🧠📈 🧪
www.biorxiv.org/content/10.1...
I personally am a big fan of the idea that cortical regions (allo and neo) are doing sequence prediction.
But...
🧠📈 🧪
Sensory responses of visual cortical neurons are not prediction errors
Predictive coding is theorized to be a ubiquitous cortical process to explain sensory responses. It asserts that the brain continuously predicts sensory information and imposes those predictions on lo...
www.biorxiv.org
July 11, 2025 at 3:45 PM
1/3) This may be a very important paper, it suggests that there are no prediction error encoding neurons in sensory areas of cortex:
www.biorxiv.org/content/10.1...
I personally am a big fan of the idea that cortical regions (allo and neo) are doing sequence prediction.
But...
🧠📈 🧪
www.biorxiv.org/content/10.1...
I personally am a big fan of the idea that cortical regions (allo and neo) are doing sequence prediction.
But...
🧠📈 🧪
Reposted by Steven Ryu
Trends in Cognitive Sciences
The interoceptive origin of reinforcement learning
www.cell.com/trends/cogni...
The interoceptive origin of reinforcement learning
www.cell.com/trends/cogni...
The interoceptive origin of reinforcement learning
Rewards play a crucial role in sculpting all motivated behavior. Traditionally, research
on reinforcement learning has centered on how rewards guide learning and decision-making.
Here, we examine the ...
www.cell.com
July 6, 2025 at 12:00 AM
Trends in Cognitive Sciences
The interoceptive origin of reinforcement learning
www.cell.com/trends/cogni...
The interoceptive origin of reinforcement learning
www.cell.com/trends/cogni...
Reposted by Steven Ryu
Absolutely fascinating podcast about OCD (w/ a book author who has lived experience). Among the tidbits: this 1978 study about intrusive thoughts in OCD and typical populations.
Ergo: If intrusive thoughts enter your mind from time to time, you aren't alone.
The podcast:
rss.com/podcasts/lea...
Ergo: If intrusive thoughts enter your mind from time to time, you aren't alone.
The podcast:
rss.com/podcasts/lea...
July 6, 2025 at 8:27 AM
Absolutely fascinating podcast about OCD (w/ a book author who has lived experience). Among the tidbits: this 1978 study about intrusive thoughts in OCD and typical populations.
Ergo: If intrusive thoughts enter your mind from time to time, you aren't alone.
The podcast:
rss.com/podcasts/lea...
Ergo: If intrusive thoughts enter your mind from time to time, you aren't alone.
The podcast:
rss.com/podcasts/lea...
Reposted by Steven Ryu
🆕 perspective from @flanbrain.bsky.social et al on how machine learning algorithms such as AlphaFold, which predict 3D protein structures, can facilitate drug discovery in neuropsychopharmacology. Check it out!!
www.nature.com/artic...
www.nature.com/artic...
Neuropsychopharmacology in the era of artificial intelligence and biomolecule prediction software
NPP—Digital Psychiatry and Neuroscience - Neuropsychopharmacology in the era of artificial intelligence and biomolecule prediction software
www.nature.com
June 30, 2025 at 1:38 PM
🆕 perspective from @flanbrain.bsky.social et al on how machine learning algorithms such as AlphaFold, which predict 3D protein structures, can facilitate drug discovery in neuropsychopharmacology. Check it out!!
www.nature.com/artic...
www.nature.com/artic...
Reposted by Steven Ryu
This paper, from @smellosopher.bsky.social et al, is a well-designed spherical cow with a lot of 🥛 to give.
Has been quite influential in how I think of #NeuroAI and ANNs as models for the brain 🐮
onlinelibrary.wiley.com/doi/10.1111/...
Has been quite influential in how I think of #NeuroAI and ANNs as models for the brain 🐮
onlinelibrary.wiley.com/doi/10.1111/...
June 30, 2025 at 1:17 PM
This paper, from @smellosopher.bsky.social et al, is a well-designed spherical cow with a lot of 🥛 to give.
Has been quite influential in how I think of #NeuroAI and ANNs as models for the brain 🐮
onlinelibrary.wiley.com/doi/10.1111/...
Has been quite influential in how I think of #NeuroAI and ANNs as models for the brain 🐮
onlinelibrary.wiley.com/doi/10.1111/...
Reposted by Steven Ryu
New work! Learning is assumed to involve synaptic plasticity, but which specific synapses change to enable higher order cognitive functions? We actually find that cognitive flexibility involves potentiation of long-range GABAergic synapses from prefrontal PV neurons: www.biorxiv.org/content/10.1...
Synaptic plasticity of prefrontal long-range inhibition regulates cognitive flexibility
While glutamatergic synaptic plasticity is believed to be a fundamental mechanism mediating learning, the behavioral significance of plasticity at cortical GABAergic synapses remains less well underst...
www.biorxiv.org
June 30, 2025 at 5:55 PM
New work! Learning is assumed to involve synaptic plasticity, but which specific synapses change to enable higher order cognitive functions? We actually find that cognitive flexibility involves potentiation of long-range GABAergic synapses from prefrontal PV neurons: www.biorxiv.org/content/10.1...
Reposted by Steven Ryu
Reposted by Steven Ryu
Check out these 5 Big Ideas (audio and text) from my new book, Elusive Cures. All centered around the question: What will it take to treat & cure the most formidable brain disorders?
Thank you @nextbigidea.bsky.social for selecting Elusive Cures to profile.
urldefense.com/v3/__https:/...
Thank you @nextbigidea.bsky.social for selecting Elusive Cures to profile.
urldefense.com/v3/__https:/...
A Neuroscientist’s Bold Proposal for Solving Brain Disorders
Author Nicole Rust shares 5 key insights from her new book, Elusive Cures: Why Neuroscience Hasn’t Solved Brain Disorders―and How We Can Change That.
urldefense.com
June 28, 2025 at 12:10 PM
Check out these 5 Big Ideas (audio and text) from my new book, Elusive Cures. All centered around the question: What will it take to treat & cure the most formidable brain disorders?
Thank you @nextbigidea.bsky.social for selecting Elusive Cures to profile.
urldefense.com/v3/__https:/...
Thank you @nextbigidea.bsky.social for selecting Elusive Cures to profile.
urldefense.com/v3/__https:/...