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bioRxiv · 10.1101/2025.11.11.687899

Visual landmark coding and dynamic coupling with path integration circuits in area 29e of the rodent parahippocampal cortex

Secer, G.·Krishnan, B.·Cowan, N.·Knierim, J. J.
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Abstract

External landmarks anchor internal spatial representations. The neural mechanisms underlying this process and the sources of landmark signals remain unknown. We recorded neurons across five parahippocampal regions while rats navigated in a virtual reality apparatus, inducing conflict between self-motion and landmark cues. Area 29e, a parahippocampal field putatively homologous to primate area prostriata, maintained firing coupled to landmarks even when other regions decoupled from the landmarks. This decoupling was preceded by a decline of gamma-band influence from 29e to MEC and a concomitant decline of theta-modulated feedback from MEC to 29e. Area 29e also displayed weak theta modulation, strong gamma rhythmicity, strong egocentric head-direction tuning, and enhanced landmark contrast sensitivity. These findings provide strong evidence that 29e serves as a specialized visuospatial hub that provides landmark signals for anchoring parahippocampal spatial representations to the external world.

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Secer, G., Krishnan, B., Cowan, N., Knierim, J. J.. 2025-11-12. Visual landmark coding and dynamic coupling with path integration circuits in area 29e of the rodent parahippocampal cortex. https://doi.org/10.1101/2025.11.11.687899

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