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Raeed Chowdhury

@raeedcho.com
932 followers 285 following 19 posts

Research Assistant Professor at the University of Pittsburgh Studying the neuroscience of how we move

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Reposted by Raeed Chowdhury
Jonathan A. Michaels @jonathanamichaels.bsky.social · 12/06/2026
Many of the scientific questions we're interested in tackling require studying learning over long periods of time across the brain. This is challenging – which is why we're excited to say we've been developing a system for chronic wireless recording using long Neuropixels probes in macaque monkeys.
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Raeed Chowdhury @raeedcho.com · 15/04/2026
Credit to Sherry An who did most of the work here, and the other co-authors, Josh Glaser (@joshuaiglaser.bsky.social), Lee Miller, and Kyle Blum. Here's the link again--hope you check it out! doi.org/10.64898/202... 11/11
doi.org
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Raeed Chowdhury @raeedcho.com · 15/04/2026
Altogether, these results suggest that the orthogonality of CD and FB signals in area 2 enable flexible integration downstream for either body state estimation or for adapting to external perturbation 10/
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Raeed Chowdhury @raeedcho.com · 15/04/2026
At the same time, we found that for trying to detect external perturbations, the orthogonal and opposite geometries could succeed, but the aligned geometry could not. 9/
Bump classification performance for orthogonal, aligned, and opposite geometry of CD and FB signals
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Raeed Chowdhury @raeedcho.com · 15/04/2026
What benefit might there be to keeping these signals separate and orthogonal? We simulated various geometries to find out. We found that both orthogonal and aligned geometries could combine the two signals for better state estimation, but an opposed geometry could not. 8/
State estimation performance in models using orthogonal, aligned, and opposite geometry of CD and FB signals
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Raeed Chowdhury @raeedcho.com · 15/04/2026
CD and FB signals in area 2 also seem to be orthogonal to each other in the full neural state space. This echos similar findings in other cortical areas, showing that, for example, motor preparation and execution lie in orthogonal neural subspaces. 7/
Histogram of Monte Carlo analysis on principal angles between corollary discharge and feedback signal subspaces
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Raeed Chowdhury @raeedcho.com · 15/04/2026
However, for passive trials (unseen by the decoding procedure), this relationship is reversed--FB dimensions come on first, and CD signals come on later, likely to coordinate the active return reach. 6/
Example corollary discharge and feedback signal dimensions during passive perturbation trials
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Raeed Chowdhury @raeedcho.com · 15/04/2026
Using an iterative decoding procedure in each of these active trial epochs, we isolated CD and FB signals. For active trials, as we would expect, we found that CD signals start before movement, and then reverse direction for the return reach. FB signals look similar, but delayed. 5/
Example corollary discharge and feedback signal dimensions during active reaching trials
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Raeed Chowdhury @raeedcho.com · 15/04/2026
In active reaching trials, we would expect corollary discharge (CD) signals, but not feedback (FB) signals, to be present in neural activity just before the reach. Likewise, just before the end of the reach, we would expect primarily feedback signals. 4/
Diagram showing the epochs where corollary discharge and feedback signals can be isolated during active reaching
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Raeed Chowdhury @raeedcho.com · 15/04/2026
To look for neural evidence of this integration, we recorded from area 2 of somatosensory cortex as monkeys actively reached to targets and were passively perturbed. 3/
Task diagram showing time course and hand trajectories of an active and passive task
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Raeed Chowdhury @raeedcho.com · 15/04/2026
Most of us interact with the world without thinking about how. A big part of this ability is sensory feedback about body movement, but because of pathway delays, we can't rely only on feedback. Instead, we integrate feedback with motor signals ("corollary discharge") into an estimated body state. 2/
Block diagram showing integration of sensory feedback and corollary discharge for motor control
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Raeed Chowdhury @raeedcho.com · 15/04/2026
New preprint! 🧵🧪🧠 doi.org/10.64898/202... Upshot: somatosensory cortex contains both feedback *and* intended movement signals (a.k.a. corollary discharge). These two signals exist orthogonally in neural space, flexibly allowing both fast state estimation and external perturbation detection. 1/
Neural trajectory plot showing neural activity moving through orthogonal corollary discharge and feedback signal subspaces
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Raeed Chowdhury @raeedcho.com · 15/04/2026
At the same time, we found that for trying to detect external perturbations, the orthogonal and opposite geometries could succeed, but the aligned geometry could not. 9/
Bump classification performance for orthogonal, aligned, and opposite geometry of CD and FB signals
000
Raeed Chowdhury @raeedcho.com · 15/04/2026
What benefit might there be to keeping these signals separate and orthogonal? We simulated various geometries to find out. We found that both orthogonal and aligned geometries could combine the two signals for better state estimation, but an opposed geometry could not. 8/
State estimation performance in models using orthogonal, aligned, and opposite geometry of CD and FB signals
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Raeed Chowdhury @raeedcho.com · 15/04/2026
CD and FB signals in area 2 also seem to be orthogonal to each other in the full neural state space. This echos similar findings in other cortical areas, showing that, for example, motor preparation and execution lie in orthogonal neural subspaces. 7/
Histogram of Monte Carlo analysis on principal angles between corollary discharge and feedback signal subspaces
100
Raeed Chowdhury @raeedcho.com · 15/04/2026
However, for passive trials (unseen by the decoding procedure), this relationship is reversed--FB dimensions come on first, and CD signals come on later, likely to coordinate the active return reach. 6/
Example corollary discharge and feedback signal dimensions during passive perturbation trials
100
Raeed Chowdhury @raeedcho.com · 15/04/2026
Using an iterative decoding procedure in each of these active trial epochs, we isolated CD and FB signals. For active trials, as we would expect, we found that CD signals start before movement, and then reverse direction for the return reach. FB signals look similar, but delayed. 5/
Example corollary discharge and feedback signal dimensions during active reaching trials
100
Raeed Chowdhury @raeedcho.com · 15/04/2026
In active reaching trials, we would expect corollary discharge (CD) signals, but not feedback (FB) signals, to be present in neural activity just before the reach. Likewise, just before the end of the reach, we would expect primarily feedback signals. 4/
Diagram showing the epochs where corollary discharge and feedback signals can be isolated during active reaching
100
Raeed Chowdhury @raeedcho.com · 15/04/2026
To look for neural evidence of this integration, we recorded from area 2 of somatosensory cortex as monkeys actively reached to targets and were passively perturbed. 3/
Task diagram showing time course and hand trajectories of an active and passive task
100
Raeed Chowdhury @raeedcho.com · 15/04/2026
Most of us interact with the world without thinking about how. A big part of this ability is sensory feedback about body movement, but because of pathway delays, we can't rely only on feedback. Instead, we integrate feedback with motor signals ("corollary discharge") into an estimated body state. 2/
Block diagram showing integration of sensory feedback and corollary discharge for motor control
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Reposted by Raeed Chowdhury
Matt Perich @mattperich.bsky.social · 10/03/2026
New paper hot off the (pre-)press! We dig into the evolutionary origins of neural computations for behavioral control across mice, monkeys, and humans: www.biorxiv.org/content/10.6.... As our lab's first foray into comparative analysis of neural dynamics, I’m super excited about this work! 1/18
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Reposted by Raeed Chowdhury
Juan Gallego @juangallego.bsky.social · 07/01/2026
🚨📜+🧵🚨 Very excited about this work showing that people with no hand function following a spinal cord injury can control the activity of motor units from those muscles to perform 1D, 2D and 3D tasks, play video games, or navigate a virtual wheelchair By a wonderful team co-mentored w Dario Farina
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Reposted by Raeed Chowdhury
Aaron Batista @aaronbatista.bsky.social · 14/09/2024
When you fail to perform at your best right when it matters the most, what's going on in your brain? We can now provide an explanation: Exceptionally high stakes interfere with the neural signals of motor preparation. I'd love to hear - what do you think causes it? sciencedirect.com/science/arti...
sciencedirect.com
A neural basis of choking under pressure
Incentives tend to drive improvements in performance. But when incentives get too high, we can “choke under pressure” and underperform right when it m…
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Reposted by Raeed Chowdhury
Juan Gallego @juangallego.bsky.social · 08/09/2024
Just created a list with the sensorimotor people I was following/followed me (inclusion criteria slightly generous) Let me know if you want to be added, and repost (?) to spread the word go.bsky.app/U4oyFgw
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