Josh Johansen

The neural basis of species-specific defensive behaviour in Peromyscus mice - Nature Visual threat triggers contrasting freeze and escape defensive responses in two species of deer mice as a result of different activation thresholds downstream of the superior colliculus in the do...

Finally it's out! www.nature.com/articles/s41... How flexible are essential innate behaviours and their underlying neural circuits? @felixbaier.bsky.social & I, with Hopi Hoekstra and @farrowlab.bsky.social, addressed this by studying the #evolution of threat avoidance in Peromyscus mice.

Great, the meeting is in good hands!

Jobs We are working to solve the biggest mysteries in bioscience.

We have an open position for a Scientist I at the Allen Institute for Neural Dynamics. Come join our exciting research environment @alleninstitute.org. Please share!

alleninstitute.org/careers/jobs...

Context-invariant socioemotional encoding by prefrontal ensembles - Nature Communications How the ensemble encoding of social and anxiety-related behaviors interacts with encoding of context in the prefrontal cortex of mice is not fully understood. Here authors examine how prefrontal neurons encode socioemotional behaviors in different contexts and reveal that the prefrontal cortex encodes context-invariant representations of these behaviors in parallel with representations of context.

(more news) New paper just published! Prefrontal representations of social and emotional information generalize across contexts (even though ensembles for socioemotional + contextual information are highly overlapping): www.nature.com/articles/s41...

Noradrenaline and microglia maintain plasticity-rigidity balance to safeguard rapid emotional learning in the prefrontal cortex https://www.biorxiv.org/content/10.1101/2025.06.16.659241v1

Multi-timescale reinforcement learning in the brain - Nature Individual dopaminergic neurons encode future rewards over distinct temporal horizons.

Our work with Pablo Tano, @hyunggoo-kim.bsky.social Athar Malik, Alexandre Pouget and @naoshigeuchida.bsky.social exploring how dopamine neurons could enable multi-timescale reinforcement learning in the brain is out in @nature.com
www.nature.com/articles/s41...

Congratulations to our Human Neural Circuitry team; bit.ly/4dEyX7Z publishes today in Science! This was the hardest challenge of my career, but one of the most rewarding, after years of rebuilding– & expanding my inpatient neuropsychiatry in the service of basic discovery bsky.app/profile/deis...

📣 #SfN25 abstract submission is now open!

Share your research with the global neuroscience community.

Start now to avoid the last-minute rush!

🔗 bit.ly/3G5vEde

#NeuroSky #AcademicChatter

Thanks!

Thanks!

Thanks Francesco! Yes, there is definitely synergy of ideas here. I'd love to talk more about it.

Thanks Alicia! Would love to hear what you think

Thanks David!

Thanks Tim! The good old days are now:)

Thanks Tom!

Thanks Keri!

Thanks Andrew!

Thanks Vinny!

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🙏

Great study, congrats! And perfect timing 😉

Systems consolidation reorganizes hippocampal engram circuitry Nature - A study shows that loss of memory precision associated with systems consolidation can be explained by neurogenesis-dependent reorganization of engram circuitry within the hippocampus over...

Sharing a new paper from the lab. This paper, led by Sangyoon Ko, represents a merging of two longstanding research themes in the lab-- adult neurogenesis and systems consolidation.

rdcu.be/el18q

A short thread follows for those interested.

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These findings reveal a neural coding and circuit-based mechanism for model-based emotional processing in dmPFC, opening a new path for emotion research and establishing a conceptual framework for studying the brain mechanisms of higher order emotions in health and disease. (8/8)

Finally, we discovered that a specific population of mPFC neurons which project to the amygdala specifically encode and are required for recall of inferred emotional memories, but not memories for stimuli which were directly associated with aversive events (7/8)

We also identified a novel coding/plasticity mechanism for forming these types of internal models. While sensory-sensory learning doesn't affect population coding, it tags a specific population of mPFC neurons which are then captured during aversive learning and used for inferred memory recall.(6/8)

Unlike areas like the hippocampus and orbitofrontal cortex, mPFC population activity did not encode sensory-sensory associations alone. Dramatic changes in mPFC representational structure were only apparent following aversive learning (5/8)

We found that mPFC neurons encode a flexible internal model of emotional associations, boosting and linking mPFC representations of aversive events with representations of stimuli which were directly or indirectly associated with them. (4/8)

We used longitudinal miniscope calcium imaging and optogenetics to examine whether and, if so, how prelimbic mPFC neurons encode internal models of emotion which reflect sensory-sensory associations and their direct or indirect relationship with an aversive experience (3/8)

Emotions are rich and complex, often arising from internal brain models which evaluate situations in the context of our life experience. While we understand simple forms of emotional learning involving areas like amygdala, the mechanisms of complex emotions are unclear. (2/8)

Prefrontal encoding of an internal model for emotional inference Nature - Neurons in the rodent dorsomedial prefrontal cortex encode a flexible internal model of emotion by linking directly experienced and inferred associations with aversive experiences.

I’m excited to share a new paper from the lab. The study led by Xiaowei Gu reveals how the mPFC encodes complex emotional memories, using an internal model to infer emotional associations and memories via projections to the amygdala. a🧵(1/8)

rdcu.be/el19t