Retrosplenial cortex maps the conjunction of internal and external spaces

Abstract

Intelligent behavior demands not only multiple forms of spatial representation, but also coordination among the brain regions mediating those representations. Retrosplenial cortex is densely interconnected with the majority of cortical and subcortical brain structures that register an animal's position in multiple internal and external spatial frames of reference. This unique anatomy suggests that it functions to integrate distinct forms of spatial information and provides an interface for transformations between them. Evidence for this was found in rats traversing two different routes placed at different environmental locations. Retrosplenial ensembles robustly encoded conjunctions of progress through the current route, position in the larger environment and the left versus right turning behavior of the animal. Thus, the retrosplenial cortex has the requisite dynamics to serve as an intermediary between brain regions generating different forms of spatial mapping, a result that is consistent with navigational and episodic memory impairments following damage to this region in humans.

Principles governing the integration of landmark and self-motion cues in entorhinal cortical codes for navigation

“…Specifically, during VR gain reduction, place cells shifted backward by an amount that did not grow with distance since the start of the track. These data strongly resemble the sub-critical regime of our model, raising the intriguing possibility that some of the principles we reveal governing the integration of different information sources by MEC neural codes may generalize to other brain regions that support spatial navigation 46–49 .…”

Electrophysiological Evidence That the Retrosplenial Cortex Displays a Strong and Specific Activation Phased with Hippocampal Theta during Paradoxical (REM) Sleep

“…One possibility is that theta recorded in the HPC and the RSC is 451 driven by a common subcortical source. This is very likely since it has been recently 452 shown that medial septum GABAergic neurons generating theta during PS (Borhegyi 453 neurons exhibits head-direction tuning preferences (Cho and Sharp, 2001) and map 513 the conjunction of internal and external spaces (Alexander and Nitz, 2015). In view of 514 all these and our results, the activation of RSC neurons during PS and their phase 515 locked activity to theta oscillation could be involved in contextual memory 516 consolidation.…”

A neural-level model of spatial memory and imagery

“…Future work should try to integrate the present account of spatial cognition with recent progress concerning spatial coding in parietal areas (Nitz, 2006; Nitz, 2009; Nitz, 2012; Harvey et al, 2012; Whitlock et al, 2012; Raposo et al, 2014; Vedder et al, 2017), and a broader view of retrosplenial function (e.g., Alexander and Nitz, 2015; Alexander and Nitz, 2017). Notably, BVCs were predicted by an early predecessor of the present model (Hartley et al, 2000; Burgess et al, 2001a).…”

“…The transformation between egocentric (parietal) and allocentric (MTL) reference frames is performed by a gain-field circuit in retrosplenial cortex (Burgess et al, 2001a; Byrne et al, 2007; Wilber et al, 2014; Alexander and Nitz, 2015; Bicanski and Burgess, 2016), analogous to gain-field neurons found in posterior parietal cortex (Snyder et al, 1998; Salinas and Abbott, 1995; Pouget and Sejnowski, 1997; Pouget et al, 2002) or parieto-occipital areas (Galletti et al, 1995). Head-direction provides the gain-modulation in the transformation circuit, producing directionally modulated boundary vector cells which connect egocentric and allocentric boundary coding neurons.…”