Elise Deng

Presentation Title

 Visual Landmark Coding in the Retrosplenial Cortex of Freely Moving Mice

Abstract

The transformation of egocentric sensory cues into an allocentric map is a necessary yet poorly understood neural computation in spatial navigation. The retrosplenial cortex (RSC) is an association cortex that exhibits reciprocal connectivity with multiple sensorimotor processing areas and the hippocampal formation, a region critical in spatial cognition and navigation. In mouse virtual-reality experiments, RSC is known to encode multiple self-motion signals (e.g. optic flow, speed) and visual landmark locations. Thus, the RSC is well positioned to contribute to transformations between reference frames. However, VR preparations inherently restrict the full range of idiothetic input, limiting the ethological validity of these findings. Here, we assess RSC-dependent landmark processing in freely-moving mice trained to run uninterrupted along a circular track featuring identical, equidistant cues. This behavior is paired with head-mounted 2-photon calcium imaging to further characterize landmark coding in RSC at the single-cell and population level. Our data identify multiple subpopulations of RSC neurons nonlinearly modulated by position, movement direction, and reference frame, suggesting that RSC plays a role in coordinate system transformations during naturalistic navigation.