Erratum:
"Starting 2026 with a thread on a very recent manuscript from the Ryan Lab"

(Bluesky does not allowing posts to be edited).

Lastly, many thanks to the Editors at @plosbiology.org for a serious, efficient, and scholarly approach to peer review. My first time submitting to this journal, and I was very impressed.

The study was conducted at @tbsi-tcd.bsky.social in @tcddublin.bsky.social

Special thanks to our funders, especially AFOSR🇺🇸 who enabled this project. This work was also supported by CIFAR🇨🇦, the Irish Research Council (IRC) 🇮🇪, @researchireland.ie (SFI)🇮🇪 , & @erc.europa.eu🇪🇺

Many thanks for the resilient efforts of all contributing authors in the broader Ryan Lab, and our collaborators.

#scienceisglobal
🇮🇪🇮🇹🇬🇹🇫🇷🇸🇬🇺🇸🇺🇸🇪🇸🇦🇺🇬🇧🇮🇹🇮🇪🇪🇺

This project represents a large portion of Paul Conway's PhD thesis at @tcddublin.bsky.social
.
Paul has since moved to the lab of Jonny Kohl at @crick.ac.uk crick in London for his Postdoctoral career.

Hugely looking forward to seeing what he does next!

bsky.app/profile/tjry...

Paul first presented this work at @fens.org Forum 2022 in Paris, and again at @sfn.org 2023 in Washington DC. It has improved hugely with useful feedback from colleagues:

After years of effort and many challenges, false starts, and blind alley ways - this work was first published in December 2024:

bsky.app/profile/tjry...

Future work will interrogate evolutionary aspects of ingram formation, asking whether learning and evolution find similar or different solutions to the same environmental challenges.

direct.mit.edu/books/edited...

Through a series of carefully controlled and technically demanding experiments, Paul (Conway) & Livia (Autore) determined that innate vCA1 ingram ensembles became necessary for the visual looming threat response after, but not before, the reinstatement training.

With the substantial help of close collaborator Gisella Vetere
at @espciparispsl.bsky.social, we were able to quickly and effectively incorporate the use of FLiCRE for vCA1 engram labeling during looming reinstatement.

But standard engram methods cannot capture this time window of experience.

So, we adopted the next generation calcium-based labeling technique FLiCRE (Fast Light and Calcium-Regulated Expression) from @tinakim-neuro.bsky.social
& @aliceyting.bsky.social

www.sciencedirect.com/science/arti...

A specific vCA1 ensemble was reactivated by sequential looming experiences, unaffected by extinction training, and showed increased reactivation after behavioral reinstatement.

We sought to experimentally interrogate the function of this engram (or putative ingram).

This prompted us to look more broadly, using c-Fos histology and engram labeling to assay multiple brain regions.

Ventral hippocampal region CA1 emerged as a striking and opportunistic candidate region to explain the reinstatement effect.