Environment symmetry drives a multidirectional code in rat retrosplenial cortex

Abstract

A class of neurons showing bidirectional tuning in a two-compartment environment was recently discovered in dysgranular retrosplenial cortex (dRSC). We investigated here whether these neurons possess a more general environmental symmetry-encoding property, potentially useful in representing complex spatial structure. We report that directional tuning of dRSC neurons reflected environment symmetry in onefold, twofold and fourfold-symmetric environments: this was the case not just globally, but also locally within each sub-compartment. Thus, these cells use environmental cues to organize multiple directional tuning curves, which perhaps sometimes combine via interaction with classic head direction cells. A consequence is that both local and global environmental symmetry are simultaneously encoded even within local sub-compartments, which may be important for cognitive mapping of the space beyond immediate perceptual reach. One Sentence SummaryRetrosplenial directionally tuned neurons encode global environment symmetry even in local sub-compartments.