Reposted by Raeed ChowdhuryJonathan A. Michaels @jonathanamichaels.bsky.social · 12/06/2026Many 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. 78622
Raeed Chowdhury @raeedcho.com · 15/04/2026Credit 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... 11/11doi.org 030
Raeed Chowdhury @raeedcho.com · 15/04/2026Altogether, 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/ 140
Raeed Chowdhury @raeedcho.com · 15/04/2026At 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/ 110
Raeed Chowdhury @raeedcho.com · 15/04/2026What 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/ 120
Raeed Chowdhury @raeedcho.com · 15/04/2026CD 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/ 133
Raeed Chowdhury @raeedcho.com · 15/04/2026However, 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/ 110
Raeed Chowdhury @raeedcho.com · 15/04/2026Using 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/ 101
Raeed Chowdhury @raeedcho.com · 15/04/2026In 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/ 111
Raeed Chowdhury @raeedcho.com · 15/04/2026To 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/ 121
Raeed Chowdhury @raeedcho.com · 15/04/2026Most 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/ 112
Raeed Chowdhury @raeedcho.com · 15/04/2026New 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/ 34619
Raeed Chowdhury @raeedcho.com · 15/04/2026At 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/ 000
Raeed Chowdhury @raeedcho.com · 15/04/2026What 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/ 100
Raeed Chowdhury @raeedcho.com · 15/04/2026CD 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/ 100
Raeed Chowdhury @raeedcho.com · 15/04/2026However, 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/ 100
Raeed Chowdhury @raeedcho.com · 15/04/2026Using 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/ 100
Raeed Chowdhury @raeedcho.com · 15/04/2026In 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/ 100
Raeed Chowdhury @raeedcho.com · 15/04/2026To 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/ 100
Raeed Chowdhury @raeedcho.com · 15/04/2026Most 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/ 100
Reposted by Raeed ChowdhuryMatt Perich @mattperich.bsky.social · 10/03/2026New 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 614148
Reposted by Raeed ChowdhuryJuan 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 17517
Reposted by Raeed ChowdhuryAaron Batista @aaronbatista.bsky.social · 14/09/2024When 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.comA neural basis of choking under pressureIncentives tend to drive improvements in performance. But when incentives get too high, we can “choke under pressure” and underperform right when it m… 1319
Reposted by Raeed ChowdhuryJuan Gallego @juangallego.bsky.social · 08/09/2024Just 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 12416