Greg Stephens
@gjstephens.bsky.social
140 followers 130 following 25 posts
Theoretical physicist thinking about living and complex systems. Faculty at VU Amsterdam & OIST Graduate University
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gjstephens.bsky.social
Yay for worms!
michaelhendricks.bsky.social
I'll never get tired of these.

(courtesy of Sebasitan Wittekindt doi.org/10.1101/2025...)
gjstephens.bsky.social
As a former selection committee member, I can say it's really quite a joy to learn about all of your interesting directions!
gjstephens.bsky.social
Within 7 years of the start of your independent position, apply for the APS DBIO early career award! engage.aps.org/dbio/honors/...
Prizes & Awards - Unit - DBIO
engage.aps.org
gjstephens.bsky.social
Fun!
antihebbiann.bsky.social
And we are live!

Excited to announce the 2025 Multi-Agent Behavior Challenge on cross-lab supervised action recognition in mice 🐁🐀🖱️

Running on Kaggle until December 15th, with a $50,000 prize pool going to the top five submissions!

www.kaggle.com/competitions...
https://www.kaggle.com/competitions/MABe-mouse-behavior-detection
gjstephens.bsky.social
What’s a few neurons among friends!
gjstephens.bsky.social
This looks really cool!
micromotility.bsky.social
Complex behaviour is not limited to animals! Here we map the entire spectrum of waveforms dynamics on a quadriflagellate single cell with 4x 70um (!) #cilia, to a low dimensional behavioural manifold with surprising structure! #protistsonsky

All revealed in our new preprint doi.org/10.1101/2025...
gjstephens.bsky.social
This is good!
itaiyanai.bsky.social
The difference between doing a project and presenting it. An observation can lead to many avenues of explorations before focus turns to a specific discovery. Presenting it, in a talk / paper, follows inversely, with broad perspectives coming before & after the specific discovery.
gjstephens.bsky.social
Great course in a beautiful and storied location!
jaxeducation.bsky.social
📢🧠 #Neuroscience researchers: Level up your skills and reimagine behavior quantification at @jacksonlab.bsky.social's #MachineLearning Course from Oct. 12 – 17.

Organized by @vivekdna.bsky.social, @gordonberman.bsky.social‬, @goldenneuron.bsky.social & Ann Kennedy.

More details and link below 👇
JAX Short Course on the Application of Machine Learning for Automated Quantification of Behavior flyer. Visit jax.org/AutoBehavior for more details.
gjstephens.bsky.social
This will be quite fun! Join us in September for "“Physics of Adaptation & Decision Making in Biology” www.fluidlab.nl/padm25
VPF10 — Research Group | Mazi Jalaal | UvA
www.fluidlab.nl
Reposted by Greg Stephens
micromotility.bsky.social
We have a postdoc opening for a protistologist with biophysics inclinations to join our @hfspo.bsky.social project! (focus will be on characterising the morphology, ultrastructure and behaviour of excavates) #protistsonsky

Apply by Sept 17th (RTs appreciated!)
jobs.exeter.ac.uk/hrpr_webrecr...
gjstephens.bsky.social
Well-deserved!
juangallego.bsky.social
Very happy about my former mentor Sara Solla having received the Valentin Braitenberg Award for her lifelong contributions to computational neuroscience!

Sara will be giving a lecture at the upcoming @bernsteinneuro.bsky.social meeting which you shouldn't miss.

bernstein-network.de/en/newsroom/...
Sara A. Solla receives the Valentin Braitenberg Award for Computational Neuroscience 2025 – Bernstein Network Computational Neuroscience
bernstein-network.de
gjstephens.bsky.social
(4/4) In mecp2 mutants, an autism model, we show that predictive information is reduced overall, but especially for synergistic flows, an indication of difficulties in more complex social behaviors. We look forward to a continuing conversation about what it means to be (quantitatively) social!
gjstephens.bsky.social
(3/4) We ground our approach in the body trajectories of two adult zebrafish engaged in a dominance contest. We find that information flows align with concepts such as dominance and mirroring, and that asymmetries in self-unique and redundant information reflect the emergent dominance relationship.
gjstephens.bsky.social
(2/4) Even in this era of pose tracking of almost any organism, the analysis of social behavior is challenging, often using specific assays and human-derived labels. We instead suggest that redundant, unique, and synergistic predictive information flows provide a natural set of social variables.
gjstephens.bsky.social
(1/4) I’m happy to introduce our new work led by PhD student Akira Kawano (not on Bluesky), which explores social behavior as mutual prediction, quantified by the decomposition of information (PID) between the past and future of a multi-organism system: doi.org/10.1101/2025...
Decomposing Predictive Information in Social Dynamics
Social behaviors include some of the most interesting interactions in living systems yet their characterization is often qualitative or specialized to particular organisms and assays. Here we suggest that at the core of social interactions is the notion of mutual prediction, which we analyze in the context of two male zebrafish engaged in a dominance contest. Using 3D velocity trajectories, we construct the mutual information between a two-animal past and one-animal future, and we quantify the redundant, unique, and synergistic components using partial information decomposition (PID). As social behaviors can change rapidly in time, we compute PID using a sliding time window, and we choose the window size to maximize total information. We find that our predictive information decomposition naturally aligns with important social concepts, such as mirroring and dominance. At the end of the contest, we find asymmetries in self-unique and redundant information which align with the emergent dominance relationship. During the contest, we find that redundant information increases, showing that predictive information is increasingly shared between individuals. In contrast synergistic and unique information, which capture information exchange, are approximately constant. Applied to mecp2 zebrafish mutants, an autism model, we find that predictive information is reduced overall, but especially for synergistic flows, which is indicative of difficulties in more complex social dynamics. Significance Statement Social interactions are rich and diverse, ranging from mirroring to complementary actions. A unifying framework for defining and analyzing such interaction types has long been needed. Here, based on modern information theory, we formulate how the past state of interacting organisms encodes the future state of an individual. This framework provides a natural decomposition of pairwise social dynamics into mirroring, independent action, directed influence, and joint action. Applied to dominance contests in zebrafish, these modes of interaction capture distinct phases of conflict, their assessment strategies, and the resulting dominance relationships. Moreover, our analysis reveals a specific disruption in the social behavior of mutant zebrafish linked to autism, shedding new light on impairments in communication and social learning. ### Competing Interest Statement The authors have declared no competing interest. OIST Graduate University
doi.org
gjstephens.bsky.social
Oh yes!
itaiyanai.bsky.social
Kerouac with advice on how to find a science buddy.
Reposted by Greg Stephens
science.org
For the first time, scientists have filmed microscopic worms called nematodes in the wild as they glom together and form large wriggling masses.

Learn more: scim.ag/3FBwSx3
gjstephens.bsky.social
Revolutionary when idTracker first came on the scene, so really excited to get to know the new approach!
polavieja.bsky.social
It took us many years to improve idtracker.ai in both accuracy and tracking time. Here it is.
Reposted by Greg Stephens
oistedu.bsky.social
The OIST Graduate School has opened a Special PhD Admissions Portal for students currently enrolled in, or accepted to, universities in the U.S. #PhDProgram www.oist.jp/admissions/s...
Special Application Deadline for Students Accepted or Studying in the United States
www.oist.jp
gjstephens.bsky.social
We are happy for feedback and plan to add more!
gjstephens.bsky.social
The tutorials explore principal components analysis, state space embedding, and Markov modeling, all through the dynamics of posture. They are the result of tremendous contributions from my own group members, as well as constructive feedback from participants at special-topics schools.