ΔFosB accumulation in hippocampal granule cells drives cFos pattern separation during spatial learning

Abstract

Mice display signs of fear when neurons that express cFos during fear conditioning are artificially reactivated. This finding gave rise to the notion that cFos marks neurons that encode specific memories. Here we show that cFos expression patterns in the mouse dentate gyrus (DG) change dramatically from day to day in a water maze spatial learning paradigm, regardless of training level. Optogenetic inhibition of neurons that expressed cFos on the first training day affected performance days later, suggesting that these neurons continue to be important for spatial memory recall. The mechanism preventing repeated cFos expression in DG granule cells involves accumulation of ΔFosB, a long-lived splice variant of FosB. CA1 neurons, in contrast, repeatedly expressed cFos. Thus, cFos-expressing granule cells may encode new features being added to the internal representation during the last training session. This form of timestamping is thought to be required for the formation of episodic memories.

Bibliographical data

Original languageEnglish
Article number6376
ISSN2041-1723
DOIs
Publication statusPublished - 26.10.2022

Comment Deanary

Lea Aksutat was part of the Research Group Behavioral Biology (with F. Morellini). Lennart Beck was part of the Institute for Synaptic Physiology. Joachim Ahlbeck was affiliated with the Institute of Andreas Engel (Department of Neurophysiology and Pathophysiology).

PubMed 36289226