THE ROLE OF POSTRHINAL CORTEX REACTIVATIONS IN ADAPTIVE LEARNING

Adaptive behaviour depends on learning to make adjustments in response to cues that predict safety, reward, or threat. Visual cues, in particular, can acquire meaning through experience, signalling when to act to obtain rewards, avoid negative outcomes, or suppress defensive responses. The postrhinal cortex (POR), a visual-association region, contributes to both reward‑based learning^1,2 and the suppression of instinctive escape³. This raises the question of whether neuronal reactivations – later reinstatements of experience‑related activity patterns during rest and sleep – within the POR help consolidate visual associations, and whether shared or distinct circuits support reward seeking versus threat suppression.
To investigate this, mice learned reward associations with high-contrast gratings in an open arena with a shelter, while dark looming stimuli were interleaved to assess innate escape response and their suppression with repeated exposure.
Neuropixels recordings in freely-moving mice track POR activity during learning and subsequent rest and sleep. Current analyses examine whether reward learning and the learned suppression of threat responses recruit overlapping or distinct neurons, and whether these assemblies show cue‑specific reactivations during rest relative to neutral stimuli. Ongoing experiments will test whether disrupting POR reactivations impairs learning. This work aims to clarify how cortical reactivations support the consolidation of flexible, visually guided adaptive behaviours
1. Ramesh, RN. et al. Neuron, Volume 100, Issue 4, 900 - 915.e9. DOI: 10.1016/j.neuron.2018.09.024
2. Burgess, CR. et al. Neuron, Volume 91, Issue 5, 1154 – 1169. DOI: 10.1016/j.neuron.2016.07.032
3. Mederos, S. et al. Science, Volume 387, Issue 6734, 682-688. DOI: 10.1126/science.adr2247