Paul Masset's Avatar

Paul Masset

@paulmasset.bsky.social

Assistant Professor, McGill University | Associate Academic Member, Mila - Quebec AI Institute | Neuroscience and AI, learning and inference, dopamine and cognition https://massetlab.org/

3,705 Followers  |  1,135 Following  |  31 Posts  |  Joined: 31.01.2024  |  1.932

Latest posts by paulmasset.bsky.social on Bluesky

McGill University in early Autumn

McGill University in early Autumn

Delighted to share that we are currently hiring for a tenure-track position (open rank) in Clinical Psychology in the Department of Psychology at McGill University. Come join a great department! Link to apply: mcgill.wd3.myworkdayjobs.com/en-US/mcgill....

23.09.2025 18:56 β€” πŸ‘ 41    πŸ” 30    πŸ’¬ 1    πŸ“Œ 1

This is one of the most outstanding examples of circuit understanding I've seen in a long time. The unification of theory and experiment is beautiful.

When Malcolm presented this in my lab, the audience was cheering at the end, and one person shouted (non-ironically) "You did it!"

19.09.2025 13:37 β€” πŸ‘ 105    πŸ” 21    πŸ’¬ 4    πŸ“Œ 0

Finally preprinted! TL;DR: thalamic head-direction neurons can shape their activity regardless of input. Big thanks to @apeyrache.bsky.social and master experimentalist @sskromne.bsky.social .

16.09.2025 20:25 β€” πŸ‘ 27    πŸ” 6    πŸ’¬ 0    πŸ“Œ 0

Stoked to see this paper finally out!

It answers two big questions: where visual objects are encoded in the brain, and how head-direction cells get oriented using visual landmarks.

Super fun collaboration with @mace-lab.bsky.social and Stuart Trenholm.

www.science.org/doi/10.1126/...

11.09.2025 21:13 β€” πŸ‘ 86    πŸ” 23    πŸ’¬ 5    πŸ“Œ 1
Preview
Assistant Professor (Neuroscience, Tenure Track) - Lethbridge (City), Alberta (CA) job with University of Lethbridge | 39049 Assistant Professor (tenure track) of the Department of NeuroscienceΒ at the University of Lethbridge, Alberta, Canada

For anyone on the neuroscience job market, our ads are up. We are looking for anyone working in systems neuroscience of animals to join us in southern Alberta πŸ‡¨πŸ‡¦
#academicsky #neuroskyence #neuroethology #academicjobs #Canada
neurojobs.sfn.org/job/39049/as...

04.09.2025 19:59 β€” πŸ‘ 27    πŸ” 32    πŸ’¬ 1    πŸ“Œ 1
Professor - Computational Cognitive Neuroscience Professor - Computational Cognitive Neuroscience

Come join us at University of Toronto. We're hiring a Professor of computational cognitive neuroscience.

#neuroAI #compneuro jobs.utoronto.ca/job/Toronto-...

05.09.2025 08:22 β€” πŸ‘ 87    πŸ” 79    πŸ’¬ 2    πŸ“Œ 1
Preview
Frontiers | Summary statistics of learning link changing neural representations to behavior How can we make sense of large-scale recordings of neural activity across learning? Theories of neural network learning with their origins in statistical phy...

Since I'm back on BlueSky - with @frostedblakess.bsky.social and @cpehlevan.bsky.social we wrote a brief perspective on how ideas about summary statistics from the statistical physics of learning could potentially help inform neural data analysis... (1/2)

04.09.2025 18:30 β€” πŸ‘ 33    πŸ” 10    πŸ’¬ 1    πŸ“Œ 0
Preview
Mice navigate scent trails using predictive policies Animals actively sense their environment to extract features of interest to guide behaviors. For mammals, odors are prominent environmental features which are sampled by active modulation of sniffing ...

Thrilled to share this work, long time in the making! Carried through creatively by @siddjakes.bsky.social after initial design & piloting by @trackingskills.bsky.social, with help from @trackingactions.bsky.social. Modeling in collaboration with Massimo Vergassola & Nicola Rigolli.

01.09.2025 19:06 β€” πŸ‘ 125    πŸ” 42    πŸ’¬ 1    πŸ“Œ 2
Post image

Having fun facilitating this amazing group of young Profs at the #Neuro4Pros workshop with @kordinglab.bsky.social and @meganakpeters.bsky.social, @yaelniv.bsky.social, and Hannah Bayer.

Watch out world: this is the next generation of leaders!

compneurosci.com/Neuro4Pros/i...

26.08.2025 21:27 β€” πŸ‘ 67    πŸ” 11    πŸ’¬ 2    πŸ“Œ 2

For anyone interested in an academic job in πŸ‡¨πŸ‡¦, we will soon be advertising an Assistant Prof position in Systems Neuroscience (rodents and other animal models) at ULethbridge. There are many pros and cons of working here, so feel free to DM me to find out more
#neuroskyence #academicsky

20.08.2025 02:26 β€” πŸ‘ 67    πŸ” 41    πŸ’¬ 0    πŸ“Œ 1
Preview
Tonic dopamine and biases in value learning linked through a biologically inspired reinforcement learning model Nature Communications - Accurate future predictions are essential for guiding behavior, and disruptions in this process are associated with psychiatric disorders. Here the authors show that changes...

My first paper with @naoshigeuchida.bsky.social is finally out in @natcomms.nature.com ! rdcu.be/eACGf

TL;DR: asymmetric learning rates can be induced by shifts in tonic dopamine giving rise to pessimistic/optimistic biases in agents or animals undergoing reinforcement learning .

13.08.2025 21:55 β€” πŸ‘ 113    πŸ” 32    πŸ’¬ 1    πŸ“Œ 1

🚨 I’m excited to say that my CIHR Project Grant was funded! My NHP lab is now full-speed-ahead, and I’m hiring experimentalists (postdoc, PhD student, and/or a tech/manager). We’ll do multi-region ephys during reaching/grasping in macaques, with behavioral and spinal perturbations.

13.08.2025 16:23 β€” πŸ‘ 83    πŸ” 25    πŸ’¬ 2    πŸ“Œ 3
Preview
Reconciling flexibility and efficiency: medial entorhinal cortex represents a compositional cognitive map Nature Communications - How the brain creates compositional cognitive maps that support both flexible and efficient planning remains poorly understood. Here, authors propose a...

New paper with @nathanieldaw.bsky.social in Nature Communications: an RL model that builds a successor map compositionally. The new model plans as well as the best models, and it links components of the map used for planning to neural codes in the medial entorhinal cortex.
rdcu.be/eAofi

12.08.2025 17:18 β€” πŸ‘ 76    πŸ” 20    πŸ’¬ 1    πŸ“Œ 0
Preview
Competitive integration of time and reward explains value-sensitive foraging decisions and frontal cortex ramping dynamics Bukwich and Campbell et al. show that mice integrate elapsed time and reward intake, scaled by a latent patience variable, to decide when to leave virtual β€œpatches.” Frontal cortex ramping activity ma...

Our paper on foraging is now published in Neuron! Read it here:

www.cell.com/neuron/fullt...

This project was co-led by Michael Bukwich (not on Bluesky) and me, with major contributions from all co-authors. Huge thanks to the whole team!

07.08.2025 17:35 β€” πŸ‘ 75    πŸ” 19    πŸ’¬ 2    πŸ“Œ 1
Handbook of Behavioral Neuroscience | Volume 32: The Handbook of Dopamine | ScienceDirect.com by Elsevier Read the latest chapters of Handbook of Behavioral Neuroscience at ScienceDirect.com, Elsevier’s leading platform of peer-reviewed scholarly literature

A landmark volume, The Handbook of Dopamine, is now online:
www.sciencedirect.com/handbook/han...

Big kudos to the editors, Stephanie Cragg and Mark Walton, for putting this together.

04.08.2025 18:34 β€” πŸ‘ 71    πŸ” 23    πŸ’¬ 1    πŸ“Œ 2
Preview
A neural manifold view of the brain - Nature Neuroscience Recent advances in neuroscience have revealed how neural population activity underlying behavior can be well described by topological objects called neural manifolds. Understanding how nature, nurture...

Check out our new review/perspective (w/ @juangallego.bsky.social & Devika Narain) on neural manifolds in the brain! It was a lot of fun to think through these ideas over the past couple of years, and I'm excited it's finally out in the world!

πŸ”—: www.nature.com/articles/s41...
πŸ“„: rdcu.be/ex8hW

29.07.2025 19:06 β€” πŸ‘ 163    πŸ” 68    πŸ’¬ 2    πŸ“Œ 3
Post image

πŸ‘¨β€πŸ’» Open PI position in our institute πŸ‘¨β€πŸ’» !! If you are an expert in Computational Neuroscience and want to start your lab in Bordeaux, contact us !
www.fens.org/careers/job-...
@neuromagendie.bsky.social
@neurobordeaux.bsky.social

10.07.2025 15:13 β€” πŸ‘ 50    πŸ” 45    πŸ’¬ 0    πŸ“Œ 1
Preview
Discovering cognitive strategies with tiny recurrent neural networks - Nature Modelling biological decision-making with tiny recurrent neural networks enables more accurate predictions of animal choices than classical cognitive models and offers insights into the underlying cog...

Thrilled to see our TinyRNN paper in @nature! We show how tiny RNNs predict choices of individual subjects accurately while staying fully interpretable. This approach can transform how we model cognitive processes in both healthy and disordered decisions. doi.org/10.1038/s415...

02.07.2025 19:03 β€” πŸ‘ 329    πŸ” 141    πŸ’¬ 9    πŸ“Œ 4

Excited to share the first 2(!) preprints from the Kebschull Lab. The amazing @hyopilkim.bsky.social developed MAPseq2 & POINTseq and used them to map the dopaminergic cells of VTA and SNc. tl;dr MAPseq2=10x cheaper, 4x better; POINTseq=easy cell type specific barcoding; DA neurons=very cool.

26.06.2025 16:24 β€” πŸ‘ 36    πŸ” 12    πŸ’¬ 2    πŸ“Œ 2

Thrilled to announce I'll be starting my own neuro-theory lab, as an Assistant Professor at @yaleneuro.bsky.social @wutsaiyale.bsky.social this Fall!

My group will study offline learning in the sleeping brain: how neural activity self-organizes during sleep and the computations it performs. 🧡

23.06.2025 15:55 β€” πŸ‘ 408    πŸ” 48    πŸ’¬ 61    πŸ“Œ 7
Preview
A flexible hippocampal population code for experience relative to reward - Nature Neuroscience Sosa et al. find that hippocampal neural activity in mice encodes both environmental location and experience relative to rewards, spanning distances far from reward, through parallel and flexible popu...

It's officially published!! In my main postdoc work with @markplitt.bsky.social and @lgiocomo.bsky.social, we found that the hippocampus simultaneously encodes an animal's spatial position and its experience relative to reward in parallel population codes. 🧡

www.nature.com/articles/s41...

12.06.2025 17:24 β€” πŸ‘ 127    πŸ” 40    πŸ’¬ 9    πŸ“Œ 0
Post image

Our work, out at Cell, shows that the brain’s dopamine signals teach each individual a unique learning trajectory. Collaborative experiment-theory effort, led by Sam Liebana in the lab. The first experiment my lab started just shy of 6y ago & v excited to see it out: www.cell.com/cell/fulltex...

11.06.2025 15:17 β€” πŸ‘ 208    πŸ” 71    πŸ’¬ 7    πŸ“Œ 2
Assistant Professor (Research), Department of Psychiatry, Artificial Intelligence in Psychiatry, McGill University – Canadian Association for Neuroscience

And one more again at McGill in artificial intelligence in Psychiatry

can-acn.org/assistant-pr...

05.06.2025 18:47 β€” πŸ‘ 16    πŸ” 11    πŸ’¬ 0    πŸ“Œ 1
Manitokan are images set up where one can bring a gift or receive a gift. 1930s Rocky Boy Reservation, Montana, Montana State University photograph. Colourized with AI

Manitokan are images set up where one can bring a gift or receive a gift. 1930s Rocky Boy Reservation, Montana, Montana State University photograph. Colourized with AI

Preprint Alert πŸš€

Multi-agent reinforcement learning (MARL) often assumes that agents know when other agents cooperate with them. But for humans, this isn’t always the case. For example, plains indigenous groups used to leave resources for others to use at effigies called Manitokan.
1/8

05.06.2025 15:32 β€” πŸ‘ 35    πŸ” 13    πŸ’¬ 1    πŸ“Œ 3

To conclude our study establishes a new paradigm to understand the functional role of prediction error computation in dopaminergic neurons and opens new avenues to develop mechanistic explanations for deficits in intertemporal choice in disease and inspire the design of new RL algorithms.

04.06.2025 18:11 β€” πŸ‘ 1    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0
Post image

By recording single neurons across both tasks, we show that the discount factor at the single neuron level is correlated across tasks suggesting that discounting is a cell-specific property, constraining implementations of dopamine-based multi-timescale RL.

04.06.2025 18:11 β€” πŸ‘ 1    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0
Post image

Next, we show that heterogeneity in ramping activity across dopamine neurons when mice approach a reward in a 1-D VR track can also be understood as a signature of diverse discount factors across neurons.

04.06.2025 18:11 β€” πŸ‘ 1    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0
Post image

First, we quantify the discount factor by measuring the relative response to cues predicting rewards at different delays and show that reward timing information can be decoded from the vectorized prediction error.

04.06.2025 18:11 β€” πŸ‘ 1    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0

Next, we show in two behavioral tasks that single dopamine neurons exhibit a diversity of discount factors.

04.06.2025 18:11 β€” πŸ‘ 1    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0
Post image

We first explore four computational advantages of artificial multi-timescale RL agents:
- disentangling reward timing and reward magnitude
- learn values with non-exponential temporal discounts
- infer temporal information before convergence
- implement a state-dependent discount factor

04.06.2025 18:11 β€” πŸ‘ 4    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0

@paulmasset is following 20 prominent accounts