ePoster

Reactivations in hippocampus and V1 simulate novel trajectories through familiar space

Zuzanna Slonina, Caswell Barry, Romain Bourboulou, Thomas Jahans-Price, Robin Hayman, Matteo Carandini
COSYNE 2025(2025)
Montreal, Canada

Conference

COSYNE 2025

Montreal, Canada

Resources

Authors & Affiliations

Zuzanna Slonina, Caswell Barry, Romain Bourboulou, Thomas Jahans-Price, Robin Hayman, Matteo Carandini

Abstract

Hippocampus and primary visual cortex (V1) have been shown to represent self-location in a coordinated manner during navigation. Moreover, during rest, spatially-modulated cells in the hippocampus are known to replay past trajectories. These recapitulations of previous experiences are proposed to spread across cortical areas, constituting a hallmark of system-level consolidation theories and providing clear predictions about how hippocampus and cortex coordinate during sleep. We aimed to test these predictions by answering the following questions: 1) Can replay be detected in V1 during sleep? 2) Are trajectories replayed in V1 and hippocampus coordinated? 3) Can V1 activity ‘simulate’ novel trajectories through familiar space during sleep? We recorded concurrently from both regions in mice during interleaved sessions of navigation in virtual reality (VR) and rest. The VR environment was a linear track with asymmetric visual cues, promoting distinct representations of outbound and inbound trajectories in both regions. Initially, animals were trained to run only in the outbound direction. Remarkably, sequences of activity corresponding to inbound runs were detected in V1 and hippocampus during sleep preceding any experience of the inbound trajectory. However, trajectories decoded from V1 and hippocampal activity were rarely outright coordinated to reflect the same positions. Significant replay predominantly occurred in only one region at a time, with a small number of events where the two regions replayed independent trajectories simultaneously. These findings challenge the proposition that hippocampus and visual cortex coordinate closely during replay. Instead, they suggest a more complex interaction where these regions can operate independently during consolidation and planning processes. This independence may allow for flexible integration of spatial and sensory information, potentially enhancing the brain's ability to generalise past experiences to novel situations.

Unique ID: cosyne-25/reactivations-hippocampus-simulate-fa2b795a