Congratulations to first author Tinaïg Le Borgne for her outstanding work and Fabio marti for leading this project. Many thanks as well to our collaborators across @espciparispsl.bsky.social , @cnrsbiologie.bsky.social, @sorbonne-universite.fr and beyond!

Nicotine and alcohol seem very different, but they converge on the same circuit. Both activate NAc-projecting dopamine neurons and inhibit those projecting to the amygdala. We show that this shared loop shapes reward and emotion, helping explain their high co-use.

A circuit-level explanation for nicotine’s dual impact: Nicotine activates VTA→NAc dopamine neurons (reward), but this comes at a cost: It triggers a GABAergic feedback loop that inhibits VTA→amygdala neurons (emotion).
One drug, the dopaminergic circuits, 2 effects: reinforcement + negative affect.

free access here authors.elsevier.com/c/1kzRE3BtfH...

Congrat J. Jehl, M. Ciscato, E. Vicq & @nicolasguyon.bsky.social . Thanks to our amazing team, and collaborators! @cnrsbiologie.bsky.social , @inserm.fr , @sorbonne-universite.fr , @espciparispsl.bsky.social , @institutpasteur.bsky.social, @frm-officiel.bsky.social

This was made possible by a new chemogenetic method: a covalently tethered suicide antagonist for β4* nAChRs. Sustained, subtype-specific silencing in vivo, with single-site precision. A method developed by Alexandre Mourot in the lab @faurelab.bsky.social

Social structures are dynamic: manipulating dopamine activity reshapes role distribution, confirming a feedback loop where social context modulates neural states, which in turn reinforce specialization.

A reinforcement learning model reveals how competition for ressources drives behavioral specialization, with varying degrees of exploitation shaping social roles development and driving sex differences.

Neural and computational analyses during the task reveal that dopaminergic activity in the ventral tegmental area (VTA) plays a key role in stabilizing social roles.

Males exhibit clear divisions of labor, where worker-scrounger equilibria emerge from competitive dynamics. In contrast, females adopt more uniform & cooperative behaviors. These sex-specific differences arise only in group contexts—when tested alone, males and females show only subtle differences!

How do animals self-organize into structured societies? Using behavioral tracking, neural recordings, and reinforcement learning models, we show that small groups of isogenic mice spontaneously develop specialized roles.