Harrison Ritz
@hritz.bsky.social
cybernetic cognitive control 🤖
computational cognitive neuroscience 🧠
postdoc princeton neuro 🍕
he/him 🇨🇦 harrisonritz.github.io
computational cognitive neuroscience 🧠
postdoc princeton neuro 🍕
he/him 🇨🇦 harrisonritz.github.io
Pinned
Harrison Ritz
@hritz.bsky.social
· Jul 27
We put out this preprint a couple months ago, but I really wanted to replicate our findings before we went to publication.
At first, what we found was very confusing!
But when we dug in, it revealed a fascinating neural strategy for how we switch between tasks
doi.org/10.1101/2024.09.29.615736
🧵
At first, what we found was very confusing!
But when we dug in, it revealed a fascinating neural strategy for how we switch between tasks
doi.org/10.1101/2024.09.29.615736
🧵
Reposted by Harrison Ritz
New work by Emily Oby et al. in Nature Neuroscience demonstrates that neural population activity in motor cortex follows fixed dynamical constraints: monkeys could not volitionally reorder or reverse latent trajectories during BCI control.
www.nature.com/articles/s41...
www.nature.com/articles/s41...
Dynamical constraints on neural population activity - Nature Neuroscience
Oby, Degenhart, Grigsby and colleagues used a brain–computer interface to challenge monkeys to override their natural time courses of neural activity. They found the time courses to be highly robust, ...
www.nature.com
November 18, 2025 at 1:02 PM
New work by Emily Oby et al. in Nature Neuroscience demonstrates that neural population activity in motor cortex follows fixed dynamical constraints: monkeys could not volitionally reorder or reverse latent trajectories during BCI control.
www.nature.com/articles/s41...
www.nature.com/articles/s41...
Reposted by Harrison Ritz
My paper is out!
Computational modeling of error patterns during reward-based learning show evidence that habit learning (value free!) supplements working memory in 7 human data sets.
rdcu.be/eQjLN
Computational modeling of error patterns during reward-based learning show evidence that habit learning (value free!) supplements working memory in 7 human data sets.
rdcu.be/eQjLN
A habit and working memory model as an alternative account of human reward-based learning
Nature Human Behaviour - In this study, Collins proposes an alternative dual-process (working memory and habit) model of reinforcement learning in humans.
rdcu.be
November 17, 2025 at 5:18 PM
My paper is out!
Computational modeling of error patterns during reward-based learning show evidence that habit learning (value free!) supplements working memory in 7 human data sets.
rdcu.be/eQjLN
Computational modeling of error patterns during reward-based learning show evidence that habit learning (value free!) supplements working memory in 7 human data sets.
rdcu.be/eQjLN
Reposted by Harrison Ritz
I'm excited to co-chair an #SfN2025 nanosymposium with the esteemed @neuronush.bsky.social on intracranial and behavioral readouts of neuromodulation for psychiatric symptoms!
NANO048: "Human Intracranial Recordings: Cognitive and Clinical Science"
Wed. Nov. 19 from 8-10am (🙃)
Room 23A
NANO048: "Human Intracranial Recordings: Cognitive and Clinical Science"
Wed. Nov. 19 from 8-10am (🙃)
Room 23A
November 17, 2025 at 7:17 PM
I'm excited to co-chair an #SfN2025 nanosymposium with the esteemed @neuronush.bsky.social on intracranial and behavioral readouts of neuromodulation for psychiatric symptoms!
NANO048: "Human Intracranial Recordings: Cognitive and Clinical Science"
Wed. Nov. 19 from 8-10am (🙃)
Room 23A
NANO048: "Human Intracranial Recordings: Cognitive and Clinical Science"
Wed. Nov. 19 from 8-10am (🙃)
Room 23A
Reposted by Harrison Ritz
Happy to share my new paper published in @nathumbehav.nature.com: A critical look at statistical power in computational modeling studies, particularly those based on model selection.
www.nature.com/articles/s41...
www.nature.com/articles/s41...
November 17, 2025 at 6:13 PM
Happy to share my new paper published in @nathumbehav.nature.com: A critical look at statistical power in computational modeling studies, particularly those based on model selection.
www.nature.com/articles/s41...
www.nature.com/articles/s41...
Reposted by Harrison Ritz
periodic reminder of the existence of Atkinson Hyperlegible, a free font available from the Braille Institute designed to improve readability for people with low vision
I use it in talks because it's pretty and also because, as an audience member, I am perpetually squinting at people's slides
I use it in talks because it's pretty and also because, as an audience member, I am perpetually squinting at people's slides
Atkinson Hyperlegible Font - Braille Institute
Read easier with Atkinson Hyperlegible Font, crafted for low-vision readers. Download for free and enjoy clear letters and numbers on your computer!
www.brailleinstitute.org
November 17, 2025 at 4:19 AM
periodic reminder of the existence of Atkinson Hyperlegible, a free font available from the Braille Institute designed to improve readability for people with low vision
I use it in talks because it's pretty and also because, as an audience member, I am perpetually squinting at people's slides
I use it in talks because it's pretty and also because, as an audience member, I am perpetually squinting at people's slides
matlab now requires 2FA every time I open it
November 14, 2025 at 8:25 PM
matlab now requires 2FA every time I open it
Reposted by Harrison Ritz
Excited to share our latest Sensorimotor Superlab Journal Club. Juliana Trach joins us to discuss her latest paper with @actlab.bsky.social, now published in @nathumbehav.nature.com: Mental graphs structure the storage and retrieval of visuomotor associations. youtu.be/6LlDYxDV8wo
Juliana Trach (Yale University)
YouTube video by Andrew Pruszynski
youtu.be
November 14, 2025 at 4:20 PM
Excited to share our latest Sensorimotor Superlab Journal Club. Juliana Trach joins us to discuss her latest paper with @actlab.bsky.social, now published in @nathumbehav.nature.com: Mental graphs structure the storage and retrieval of visuomotor associations. youtu.be/6LlDYxDV8wo
Reposted by Harrison Ritz
Presenting on contingency representations in PFC during WM on Saturday at SfN! Featuring fMRI and multi-area RNN modeling from my time with John Murray 🤓
And, recruiting a PhD student for Fall ‘26 in my new lab at U-Miami! Check us out here, and feel free to reach out: jam-lab.org (apps due 12/1)
And, recruiting a PhD student for Fall ‘26 in my new lab at U-Miami! Check us out here, and feel free to reach out: jam-lab.org (apps due 12/1)
November 14, 2025 at 12:59 PM
Presenting on contingency representations in PFC during WM on Saturday at SfN! Featuring fMRI and multi-area RNN modeling from my time with John Murray 🤓
And, recruiting a PhD student for Fall ‘26 in my new lab at U-Miami! Check us out here, and feel free to reach out: jam-lab.org (apps due 12/1)
And, recruiting a PhD student for Fall ‘26 in my new lab at U-Miami! Check us out here, and feel free to reach out: jam-lab.org (apps due 12/1)
Reposted by Harrison Ritz
14 months after submission, our article “Stimulus-modulated approach to steady state (SASS): a flexible paradigm for event-related fMRI" is now out in @natmethods.nature.com . You can read it here rdcu.be/ePJo6
It is the first first author paper from my student @renilmathew.bsky.social 👏🏽👏🏽👏🏽 …1/N
It is the first first author paper from my student @renilmathew.bsky.social 👏🏽👏🏽👏🏽 …1/N
Stimulus-modulated approach to steady state (SASS): a flexible paradigm for event-related fMRI
Nature Methods - Stimulus-modulated approach to steady state (SASS) is an acquisition scheme for event-related fMRI that generates data with high temporal signal-to-noise ratios interspaced with...
rdcu.be
November 13, 2025 at 12:23 PM
14 months after submission, our article “Stimulus-modulated approach to steady state (SASS): a flexible paradigm for event-related fMRI" is now out in @natmethods.nature.com . You can read it here rdcu.be/ePJo6
It is the first first author paper from my student @renilmathew.bsky.social 👏🏽👏🏽👏🏽 …1/N
It is the first first author paper from my student @renilmathew.bsky.social 👏🏽👏🏽👏🏽 …1/N
Reposted by Harrison Ritz
Fred Crevecoeur
@fredericcrevec1
🚨preprint time by @harikalidindi.bsky.social
for our work on neural population dynamics: we show that features of neural population activity during reaching emerge from a simple linear body-network system 🧵👇
biorxiv.org/content/10.1...
@fredericcrevec1
🚨preprint time by @harikalidindi.bsky.social
for our work on neural population dynamics: we show that features of neural population activity during reaching emerge from a simple linear body-network system 🧵👇
biorxiv.org/content/10.1...
May 15, 2025 at 2:17 PM
Fred Crevecoeur
@fredericcrevec1
🚨preprint time by @harikalidindi.bsky.social
for our work on neural population dynamics: we show that features of neural population activity during reaching emerge from a simple linear body-network system 🧵👇
biorxiv.org/content/10.1...
@fredericcrevec1
🚨preprint time by @harikalidindi.bsky.social
for our work on neural population dynamics: we show that features of neural population activity during reaching emerge from a simple linear body-network system 🧵👇
biorxiv.org/content/10.1...
Reposted by Harrison Ritz
0/7 Excited to 📢 that our (@mkashefi.bsky.social @diedrichsenjorn.bsky.social @andpru.bsky.social) new preprint on sequence preparation and its effect on reaction time is now up: www.biorxiv.org/content/10.1...
Please get in touch if there is anything you'd like to discuss! Brief summary 🧵👇
Please get in touch if there is anything you'd like to discuss! Brief summary 🧵👇
Sequence preparation is not always associated with a reaction time cost
The extent to which a sequence of movements is prepared before initiating the first movement is a longstanding question in motor neuroscience. The observation that reaction time (RT) increases for lon...
www.biorxiv.org
November 13, 2025 at 11:49 PM
0/7 Excited to 📢 that our (@mkashefi.bsky.social @diedrichsenjorn.bsky.social @andpru.bsky.social) new preprint on sequence preparation and its effect on reaction time is now up: www.biorxiv.org/content/10.1...
Please get in touch if there is anything you'd like to discuss! Brief summary 🧵👇
Please get in touch if there is anything you'd like to discuss! Brief summary 🧵👇
Come check out my SFN nano talk @ 4:15 on Sunday, especially if you’re interested in:
- spicy debates in task switching
- using control theory to compare latent dynamical systems fit to RNNs and EEG
eppro02.ativ.me/appinfo.php?...
Stay for the whole ‘Adaptive Choice’ symposium!
- spicy debates in task switching
- using control theory to compare latent dynamical systems fit to RNNs and EEG
eppro02.ativ.me/appinfo.php?...
Stay for the whole ‘Adaptive Choice’ symposium!
Neuroscience 2025
eppro02.ativ.me
November 13, 2025 at 11:25 PM
Come check out my SFN nano talk @ 4:15 on Sunday, especially if you’re interested in:
- spicy debates in task switching
- using control theory to compare latent dynamical systems fit to RNNs and EEG
eppro02.ativ.me/appinfo.php?...
Stay for the whole ‘Adaptive Choice’ symposium!
- spicy debates in task switching
- using control theory to compare latent dynamical systems fit to RNNs and EEG
eppro02.ativ.me/appinfo.php?...
Stay for the whole ‘Adaptive Choice’ symposium!
Reposted by Harrison Ritz
Excited to share a new preprint, accepted as a spotlight at #NeurIPS2025!
Humans are imperfect decision-makers, and autonomous systems should understand how we deviate from idealized rationality
Our paper aims to address this! 👀🧠✨
arxiv.org/abs/2510.25951
a 🧵⤵️
Humans are imperfect decision-makers, and autonomous systems should understand how we deviate from idealized rationality
Our paper aims to address this! 👀🧠✨
arxiv.org/abs/2510.25951
a 🧵⤵️
Estimating cognitive biases with attention-aware inverse planning
People's goal-directed behaviors are influenced by their cognitive biases, and autonomous systems that interact with people should be aware of this. For example, people's attention to objects in their...
arxiv.org
November 13, 2025 at 1:20 PM
Excited to share a new preprint, accepted as a spotlight at #NeurIPS2025!
Humans are imperfect decision-makers, and autonomous systems should understand how we deviate from idealized rationality
Our paper aims to address this! 👀🧠✨
arxiv.org/abs/2510.25951
a 🧵⤵️
Humans are imperfect decision-makers, and autonomous systems should understand how we deviate from idealized rationality
Our paper aims to address this! 👀🧠✨
arxiv.org/abs/2510.25951
a 🧵⤵️
Reposted by Harrison Ritz
Profits from scientific publishing are eye-watering, costing us billions. In ‘The Drain of Scientific Publishing’ (arxiv.org/abs/2511.04820), (building on ‘The Strain of Scientific Publishing’ doi.org/10.1162/qss_a_00327) we show how it is harmful – and unnecessary.
The Drain of Scientific Publishing
The domination of scientific publishing in the Global North by major commercial publishers is harmful to science. We need the most powerful members of the research community, funders, governments and ...
arxiv.org
November 12, 2025 at 11:41 AM
Profits from scientific publishing are eye-watering, costing us billions. In ‘The Drain of Scientific Publishing’ (arxiv.org/abs/2511.04820), (building on ‘The Strain of Scientific Publishing’ doi.org/10.1162/qss_a_00327) we show how it is harmful – and unnecessary.
Reposted by Harrison Ritz
"Electrodes are held on the scalp of the patient by an arrangement of rubber and whalebone bars tied under the chin (fig. 1). A most suitable cap is one made for setting waves in hair. It is not necessary to shave the scalp, though the examination is easier if the hair is short and recently washed."
November 12, 2025 at 12:42 PM
"Electrodes are held on the scalp of the patient by an arrangement of rubber and whalebone bars tied under the chin (fig. 1). A most suitable cap is one made for setting waves in hair. It is not necessary to shave the scalp, though the examination is easier if the hair is short and recently washed."
Reposted by Harrison Ritz
Our next paper on comparing dynamical systems (with special interest to artificial and biological neural networks) is out!! Joint work with @annhuang42.bsky.social , as well as @satpreetsingh.bsky.social , @leokoz8.bsky.social , Ila Fiete, and @kanakarajanphd.bsky.social : arxiv.org/pdf/2510.25943
November 10, 2025 at 4:16 PM
Our next paper on comparing dynamical systems (with special interest to artificial and biological neural networks) is out!! Joint work with @annhuang42.bsky.social , as well as @satpreetsingh.bsky.social , @leokoz8.bsky.social , Ila Fiete, and @kanakarajanphd.bsky.social : arxiv.org/pdf/2510.25943
Reposted by Harrison Ritz
Delighted to see this finally out: rdcu.be/eO9oW
We tested whether brief striatal dopamine release events influence the vigor of skilled movements. Despite popular belief, we did not find any evidence linking rapid dopamine dynamics to motor vigor on a moment-by-moment basis.
We tested whether brief striatal dopamine release events influence the vigor of skilled movements. Despite popular belief, we did not find any evidence linking rapid dopamine dynamics to motor vigor on a moment-by-moment basis.
Subsecond dopamine fluctuations do not specify the vigor of ongoing actions
Nature Neuroscience - Liu and colleagues show that the vigor (that is, speed and amplitude) of dexterous movements is not controlled by ongoing fluctuations in extracellular dopamine within the...
rdcu.be
November 10, 2025 at 3:43 PM
Delighted to see this finally out: rdcu.be/eO9oW
We tested whether brief striatal dopamine release events influence the vigor of skilled movements. Despite popular belief, we did not find any evidence linking rapid dopamine dynamics to motor vigor on a moment-by-moment basis.
We tested whether brief striatal dopamine release events influence the vigor of skilled movements. Despite popular belief, we did not find any evidence linking rapid dopamine dynamics to motor vigor on a moment-by-moment basis.
Reposted by Harrison Ritz
Now out in #ScienceAdvances: @baiweiliu.bsky.social and I ask how internal (goal) and external (sensory) selection are coordinated during visual search. The key insight: internal and external selection are not inherently serial, but may develop in parallel in the human brain: doi.org/10.1126/scia...
Concurrent selection of internal goals and external sensations during visual search
Internal and external selection processes can codevelop in time to yield efficient search behavior.
doi.org
November 10, 2025 at 12:00 PM
Now out in #ScienceAdvances: @baiweiliu.bsky.social and I ask how internal (goal) and external (sensory) selection are coordinated during visual search. The key insight: internal and external selection are not inherently serial, but may develop in parallel in the human brain: doi.org/10.1126/scia...
Reposted by Harrison Ritz
New preprint:
Neural manifolds that orchestrate walking and stopping
Here we develop a new theory for neural generation of walking and how it can stop- Next we test the theory using Neuropixels probes in the lumber spinal cord of freely moving rats. See more:
www.biorxiv.org/content/10.1...
Neural manifolds that orchestrate walking and stopping
Here we develop a new theory for neural generation of walking and how it can stop- Next we test the theory using Neuropixels probes in the lumber spinal cord of freely moving rats. See more:
www.biorxiv.org/content/10.1...
November 9, 2025 at 9:33 PM
New preprint:
Neural manifolds that orchestrate walking and stopping
Here we develop a new theory for neural generation of walking and how it can stop- Next we test the theory using Neuropixels probes in the lumber spinal cord of freely moving rats. See more:
www.biorxiv.org/content/10.1...
Neural manifolds that orchestrate walking and stopping
Here we develop a new theory for neural generation of walking and how it can stop- Next we test the theory using Neuropixels probes in the lumber spinal cord of freely moving rats. See more:
www.biorxiv.org/content/10.1...
Reposted by Harrison Ritz
New pre-print from our lab, by Lakshmi Govindarajan with help from Sagarika Alavilli, introducing a new type of model for studying sensory uncertainty. www.biorxiv.org/content/10.1...
Here is a summary. (1/n)
Here is a summary. (1/n)
Task-optimized models of sensory uncertainty reproduce human confidence judgments
Sensory input is often ambiguous, leading to uncertain interpretations of the external world. Estimates of perceptual uncertainty might be useful in guiding behavior, but it remains unclear whether hu...
www.biorxiv.org
November 9, 2025 at 9:34 PM
New pre-print from our lab, by Lakshmi Govindarajan with help from Sagarika Alavilli, introducing a new type of model for studying sensory uncertainty. www.biorxiv.org/content/10.1...
Here is a summary. (1/n)
Here is a summary. (1/n)
Reposted by Harrison Ritz
New paper in Imaging Neuroscience by C. Sainz Martinez, J. Jorge, et al:
An optimized framework for simultaneous EEG-fMRI at 7T enabling safe, high-quality human brain imaging with millisecond temporal resolution and sub-millimeter spatial resolution
doi.org/10.1162/IMAG...
An optimized framework for simultaneous EEG-fMRI at 7T enabling safe, high-quality human brain imaging with millisecond temporal resolution and sub-millimeter spatial resolution
doi.org/10.1162/IMAG...
November 6, 2025 at 3:55 PM
New paper in Imaging Neuroscience by C. Sainz Martinez, J. Jorge, et al:
An optimized framework for simultaneous EEG-fMRI at 7T enabling safe, high-quality human brain imaging with millisecond temporal resolution and sub-millimeter spatial resolution
doi.org/10.1162/IMAG...
An optimized framework for simultaneous EEG-fMRI at 7T enabling safe, high-quality human brain imaging with millisecond temporal resolution and sub-millimeter spatial resolution
doi.org/10.1162/IMAG...
Reposted by Harrison Ritz
If you're interested in dynamical systems analysis for neuroscience, definitely check out @oliviercodol.bsky.social 's revised version of our RL paper! Very cool results in the new Fig 6, worth it regardless of if you saw our previous version or if it's all new.
www.biorxiv.org/content/10.1...
www.biorxiv.org/content/10.1...
November 6, 2025 at 5:58 PM
If you're interested in dynamical systems analysis for neuroscience, definitely check out @oliviercodol.bsky.social 's revised version of our RL paper! Very cool results in the new Fig 6, worth it regardless of if you saw our previous version or if it's all new.
www.biorxiv.org/content/10.1...
www.biorxiv.org/content/10.1...
Reposted by Harrison Ritz
Do you like RSA analysis, M/EEG and Bayes? Then you'll love Variational RSA for M/EEG, by recently completed PhD student @alexlepauvre.bsky.social from Lucia Melloni's group. It's a method and SPM toolbox for multivariate analysis of M/EEG data. arxiv.org/pdf/2511.01784 . 🧵 [1/4]
November 6, 2025 at 2:03 PM
Do you like RSA analysis, M/EEG and Bayes? Then you'll love Variational RSA for M/EEG, by recently completed PhD student @alexlepauvre.bsky.social from Lucia Melloni's group. It's a method and SPM toolbox for multivariate analysis of M/EEG data. arxiv.org/pdf/2511.01784 . 🧵 [1/4]
Reposted by Harrison Ritz
Looks great! arxiv.org/abs/2511.02063
Neural dynamics of cognitive control: Current tensions and future promise
Cognitive control is a suite of processes that helps individuals pursue goals despite resistance or uncertainty about what to do. Although cognitive control has been extensively studied as a dynamic f...
arxiv.org
November 6, 2025 at 1:34 AM
Looks great! arxiv.org/abs/2511.02063