Dendritic hotspots support switching between competing rules without expanding the cortical engram
- 1Foundation for Research and Technology-Hellas (FORTH)
Abstract
Flexible behavior depends on frontal circuits that use experience to adjust subsequent decisions. Yet how synaptic connections in these circuits are structurally reorganized when new associations compete with established ones remains unclear. Here, we used a novel rule-switching behavioral paradigm, longitudinal spine imaging, and circuit modeling to investigate how dendrites accommodate changing associations. Inactivation of secondary motor cortex (M2) impaired rule switching but not learning or maintenance in control conditions. Switching increased spine turnover on apical tuft dendrites in M2, concentrating spine formation, elimination, and new-spine clustering within persistent dendritic turnover zones, with pre-existing spines lost early during adaptation. The model reproduced these dynamics and predicted preferential elimination of synapses encoding the prior rule. Preventing dendritic compartment reuse increased the neuronal population representing the rules. These findings suggest that persistent turnover zones support synaptic reorganization during behavioral updating, with reuse offering a potential economy in neuronal recruitment.
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BibTeX
@misc{pandi2026dendritic,
title = {{Dendritic hotspots support switching between competing rules without expanding the cortical engram}},
author = {I. Pandi and S. Chavlis and H. Oraby and M. A. Nashaat and M. Larkum and A. Papoutsi and P. Poirazi},
howpublished = {bioRxiv},
year = {2026},
month = aug,
doi = {10.64898/2026.08.26.747194},
url = {https://www.biorxiv.org/content/10.64898/2026.08.26.747194v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Dendritic hotspots support switching between competing rules without expanding the cortical engram
AU - I. Pandi
AU - S. Chavlis
AU - H. Oraby
AU - M. A. Nashaat
AU - M. Larkum
AU - A. Papoutsi
AU - P. Poirazi
PY - 2026
DA - 2026/08/26
PB - bioRxiv
DO - 10.64898/2026.08.26.747194
UR - https://www.biorxiv.org/content/10.64898/2026.08.26.747194v1
AB - Flexible behavior depends on frontal circuits that use experience to adjust subsequent decisions. Yet how synaptic connections in these circuits are structurally reorganized when new associations compete with established ones remains unclear. Here, we used a novel rule-switching behavioral paradigm, longitudinal spine imaging, and circuit modeling to investigate how dendrites accommodate changing associations. Inactivation of secondary motor cortex (M2) impaired rule switching but not learning or maintenance in control conditions. Switching increased spine turnover on apical tuft dendrites in M2, concentrating spine formation, elimination, and new-spine clustering within persistent dendritic turnover zones, with pre-existing spines lost early during adaptation. The model reproduced these dynamics and predicted preferential elimination of synapses encoding the prior rule. Preventing dendritic compartment reuse increased the neuronal population representing the rules. These findings suggest that persistent turnover zones support synaptic reorganization during behavioral updating, with reuse offering a potential economy in neuronal recruitment.
ER -