Emerson Harkin

I'm excited to share that the last chapter of my PhD thesis is now published in Nature! 🍾 What drives serotonin neurons? We think it's the expectation of future reward and --- critically --- how fast this expectation is increasing. 📈 doi.org/10.1038/s415... 1/6

Super proud of many things about this work by the amazing @kristorpjensen.bsky.social. The work is one of my favourite things ever from the lab. Also super proud of Kris for choosing to send it to @elife.bsky.social - we get to see Kris explain every figure! elifesciences.org/articles/109...

It’s less than 10 days until we start reviewing applications for our postdoc position @mpicybernetics.bsky.social, if you’re interested in cross-species studies of adaptive decision-making, make sure to submit your applications by Oct 30. The deadline for our PhD position is also approaching!

1/ Why does predicting in latent space (JEPA, CPC, SimCLR...) work so well on messy data, with changing lighting, camera angles, and busy backgrounds? The usual answer: it can ignore nuisance. But that answer holds a conundrum.

Our paper "Neural timescales from a computational perspective" is finally out in @natneuro.nature.com: www.nature.com/articles/s41... We discuss how computational models and methods can distill empirical observations on neural timescales into quantitative, testable theories of brain computation.

Dopamine neurons are heterogeneous, but their diffuse axons are homogenizing. What does this mean for RL models? Stop by poster 362 at #FENS2026 this morning to find out! "Multi-timescale reward prediction learning dynamics with entangled connectivity between the striatum and the dopamine system."

Come see this paper at ICML 2026 tomorrow (July 7th)! Poster number 613 at the 2pm poster session:)

Great opportunity to work with a group that's very productive yet somehow also easygoing! To get an idea of Roxana's interests check out her recent review, just out in Nature Neuroscience: doi.org/10.1038/s415...

We (@neuroprinciplist.bsky.social & I) will soon open joint PhD & postdoc positions on cross-species mechanisms of different adaptive behaviors. If you’re interested and would like to chat during #FENS2026, drop me a message :)

Some incredibly exciting news that still feels a bit surreal: I am starting my research group @mpicybernetics.bsky.social! The best part? We are hiring at all levels! Curious about the science we plan to tackle, read along :) #NeuroSky

How are the fluctuations in electric field organized across the whole brain? We analyzed the 3.4 M samples from the international brain lab using a combination of deep learning and graph theory. We found a surprising structure made of communities and landmarks. doi.org/10.1101/2025...

What can rock-paper-scissors tell us about what I think that you think that I'm thinking? Check out this cool work to find out! 🤛🤛📄

Reproducibility challenge: How much of your paper could someone simulate for a lab journal club? observablehq.com/d/95e1ff1680...

I am excited to share my PhD work on head-direction cells recorded in the wild, now published in @science.org, where we recorded neurons in bats flying outdoors on an island. doi.org/10.1126/sci... With @ray-neuro.bsky.social, Shir Maimon, Liora Las, Nachum Ulanovsky and many others

New in @pnas.org: doi.org/10.1073/pnas... We study how humans explore a 61-state environment with a stochastic region that mimics a “noisy-TV.” Results: Participants keep exploring the stochastic part even when it’s unhelpful, and novelty-seeking best explains this behavior. #cogsci #neuroskyence

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!"

The Sosa Lab website is now live! www.sosaneurolab.com We will be seeking a postdoctoral researcher to join the growing team! If you are a rodent neuroscientist and interested in doing systems neuro work in the mountains 🏔️, please check out the "Join" page.

A nice reminder about the importance of being critical and kind in science. rdcu.be/eEzd7

So happy to see this work out! 🥳 Huge thanks to our two amazing reviewers who pushed us to make the paper much stronger. A truly joyful collaboration with @lucasgruaz.bsky.social, @sobeckerneuro.bsky.social, and Johanni Brea! 🥰 Tweeprint on an earlier version: bsky.app/profile/modi... 🧠🧪👩‍🔬

Looking forward to attending #CCN2025 for the first time and presenting the first steps of my postdoc project! If you’re interested in how learning the temporal structure of the environment affects foraging decisions and how we’re testing this in a naturalistic experiment come by poster B90, Wed.

🚨Pre-print alert🚨 We stimulated serotonin with optogenetics while doing large-scale Neuropixel recordings across the mouse brain. We found strong widespread modulation of neural activity, but no effect on the choices of the mouse 🐭 How is this possible? Strap in! (1/9) 👇🧵 doi.org/10.1101/2025...

Finally published: “Top-down and bottom-up neuroscience: overcoming the clash of research cultures” www.nature.com/articles/s41... Looking for ways to better understand different neuroscientific perspectives and enable productive collaborations

⏰ Check out this inspiring pair of articles from @paulmasset.bsky.social and Margarida Sousa! Some dopamine neurons care about rewards far in the future more than others, allowing the brain to learn the timing of future rewards. Congrats to the authors! 🍾 🔓 links: rdcu.be/epxkE rdcu.be/epxkG

1/6 Why does the brain maintain such precise excitatory-inhibitory balance? Our new preprint explores a provocative idea: Small, targeted deviations from this balance may serve a purpose: to encode local error signals for learning. www.biorxiv.org/content/10.1... led by @jrbch.bsky.social

Ugh… there’s also what I call messianic AI, the fantasy that AI will “solve” science. Treating science like a vending machine for solitons/profit & scientists as human cogs replaceable by machinery. But Science is a living culture of critical discussion, mentorship, shared community values &methods.

Sometimes negative results are also beautiful.

TIL that at certain journals the date your paper is published online might be very different from the date it appears in print. Unrelated, is there anyone whose work was published in the March 27 print edition of Nature who'd like several copies to share with supportive family members?

Most simulators for time-series data (e.g., numerical solvers for differential equations) are Markovian-- this can be exploited for efficient simulation-based inference on time-series data! Talk to Manuel and Shoji at #ICLR2025, or read the paper ⬇️!

Attention climate scholars seeking to leave the US: Next year the University of Ottawa will be seeking int'l candidates for a Canada Excellence Research Chair in "Climate and Societal Solutions" (broadly defined) They'll seek established scholars with global reach in this area (see below)...

Many people (myself included), note the lack of top-down feedback in deep NN models of the brain. Mashbayar has come to the rescue! She built a code-base for making models with top-down feedback. Check out her paper at @elife.bsky.social showing the impact of FB on audio-visual integration. 🧠📈 🧪

When a scientific idea is ambiguous, is it good to err on the side of agreeing with it? Sometimes I read discussions like "Our data are broadly consistent with X and Y," where X and Y are plausibly contradictory but vague enough that there's wiggle room.

Our latest study identifies a specific cell type and receptor essential for psilocybin’s long-lasting neural and behavioral effects 🍄🔬🧠🧪 Led by Ling-Xiao Shao and @ItsClaraLiao Funded by @NIH @NIMHgov 📄 Read in @nature.com - www.nature.com/articles/s41... 1/12

I'm always impressed when I read an article about work I was involved in that summarizes better than what I feel capable of : www.brainpost.co/weekly-brain...

1/7: Super excited to share our new paper! This one should be of interest to neuroscientists and deep learning theory folks. This paper was a collaboration with Alexandre Payeur, @averyryoo.bsky.social, Thomas Jiralerspong, @mattperich.bsky.social, Luca Mazzucato, @glajoie.bsky.social

Favourite quote from #cosyne2025 so far, from @tpvogels.bsky.social’s talk earlier today: “science is like trying to find a black cat in a dark room, and it’s not a cat”

At #COSYNE2025? Come say hi at poster 116 tonight (Thursday)!