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Greg Stephens

@gjstephens

Theoretical physicist thinking about living and complex systems. Faculty at VU Amsterdam & OIST Graduate University

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10.10.2023
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Latest posts by Greg Stephens @gjstephens

This is THE course if you want to learn how to use all the coolest new animal tracking tech!

22.02.2026 16:00 πŸ‘ 11 πŸ” 3 πŸ’¬ 0 πŸ“Œ 0
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Excited to return to Lisbon this June for the epic 3-week Cajal course on Quantitative Approaches to Behavior and VR! πŸ€πŸŸπŸͺ°πŸƒβ€β™€οΈπŸŽ₯πŸ–₯πŸ“ˆπŸ§ͺ

Applications are open through Feb 13! Come join us.
cajal-training.org/on-site/quan...

14.01.2026 13:55 πŸ‘ 23 πŸ” 11 πŸ’¬ 0 πŸ“Œ 0

I mean, it seems a very obvious "Yes"! I hope to read more.

06.12.2025 18:13 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

Call is out for Champalimaud International Neuroscience Doctoral Programme 2026! docs.google.com/forms/d/e/1F...

02.12.2025 17:50 πŸ‘ 6 πŸ” 7 πŸ’¬ 1 πŸ“Œ 0
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Boris Shraiman points a physicist’s eye on biological quandaries Boris Shraiman is awarded the American Physical Society’s Max DelbrΓΌck Prize in Biological Physics.

Boris Shraiman points a physicist’s eye on biological quandaries news.ucsb.edu/2025/022264/... πŸ§ͺ

25.11.2025 19:38 πŸ‘ 25 πŸ” 18 πŸ’¬ 0 πŸ“Œ 1
DPG Conference Server

During submission choose "SOE: Physics of Socio-economic Systems Division" and on the following page pick the topic "Focus Session: Physics of Behavior". Deadline is Dec 1st, 2025. www.dpg-tagung.de/dd26/submiss...

24.11.2025 21:52 πŸ‘ 3 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

Physics of Behavior comes to the DPG Spring Meeting, Mar 8-13 in Dresden, DE! Co-organized w/ @promanczuk.bsky.social, we welcome contributions using physical approaches to understand biological behavior across scalesβ€”from microorganisms to humans, and from individual to collective dynamics.

24.11.2025 21:52 πŸ‘ 2 πŸ” 1 πŸ’¬ 1 πŸ“Œ 0
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Buribushi Fellowship

An excellent opportunity for early-career researchers! Fellows receive salary comparable to an Assistant Professor position and research funds. For 2026, the program invites theory‑focused researchers in natural sciences and technology: www.oist.jp/research/bur... @oistedu.bsky.social

29.10.2025 17:20 πŸ‘ 3 πŸ” 2 πŸ’¬ 0 πŸ“Œ 0

Yay for worms!

27.09.2025 09:47 πŸ‘ 5 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

As a former selection committee member, I can say it's really quite a joy to learn about all of your interesting directions!

20.09.2025 07:17 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
Prizes & Awards - Unit - DBIO

Within 7 years of the start of your independent position, apply for the APS DBIO early career award! engage.aps.org/dbio/honors/...

20.09.2025 07:17 πŸ‘ 0 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

Fun!

18.09.2025 18:26 πŸ‘ 2 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

What’s a few neurons among friends!

17.09.2025 11:58 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

This looks really cool!

16.09.2025 10:59 πŸ‘ 4 πŸ” 1 πŸ’¬ 1 πŸ“Œ 0

This is good!

18.08.2025 06:41 πŸ‘ 0 πŸ” 1 πŸ’¬ 0 πŸ“Œ 0

Great course in a beautiful and storied location!

13.08.2025 13:49 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
VPF10 β€” Research Group | Mazi Jalaal | UvA

This will be quite fun! Join us in September for "β€œPhysics of Adaptation & Decision Making in Biology” www.fluidlab.nl/padm25

12.08.2025 11:18 πŸ‘ 3 πŸ” 0 πŸ’¬ 0 πŸ“Œ 1
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Emergence of Brains This review traces how ideas from statistical physics evolved into foundational models of neural computation, shaping modern AI and culminating in the 2024 Nobel Prize in Physics.

It was an honor to write this, but also great fun. A chance to look back at the classics, and think about the path forward. #Physics is a beautiful human endeavor. journals.aps.org/prxlife/abst...

09.08.2025 14:19 πŸ‘ 63 πŸ” 18 πŸ’¬ 1 πŸ“Œ 0
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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...

06.08.2025 19:19 πŸ‘ 47 πŸ” 49 πŸ’¬ 1 πŸ“Œ 0

Well-deserved!

06.08.2025 15:44 πŸ‘ 2 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

Time for more "Physics of Behavior" in single-cell settings! @micromotility.bsky.social @koseskalab.bsky.social

02.08.2025 07:39 πŸ‘ 5 πŸ” 1 πŸ’¬ 1 πŸ“Œ 0
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What’s That Splatter on Your Windshield? (Gift Article) Can you identify what insects are pelting your vehicle during your summer road trip? Take this quiz and see what you can learn from these close encounters.

Cool...but also...eew!
www.nytimes.com/interactive/...

23.07.2025 11:56 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

(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!

09.07.2025 11:42 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

(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.

09.07.2025 11:42 πŸ‘ 0 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

(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.

09.07.2025 11:42 πŸ‘ 0 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0
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

(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...

09.07.2025 11:42 πŸ‘ 8 πŸ” 0 πŸ’¬ 1 πŸ“Œ 1

Oh yes!

24.06.2025 09:27 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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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

11.06.2025 18:20 πŸ‘ 177 πŸ” 27 πŸ’¬ 14 πŸ“Œ 5

Revolutionary when idTracker first came on the scene, so really excited to get to know the new approach!

03.06.2025 18:44 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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Special Application Deadline for Students Accepted or Studying in the United States

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...

03.06.2025 04:38 πŸ‘ 6 πŸ” 18 πŸ’¬ 0 πŸ“Œ 1