Rat Retrosplenial Cortical Involvement in Wayfinding Using Visual and Locomotor Cues

Abstract

The retrosplenial cortex (RSC) has been implicated in wayfinding using different sensory cues. However, the neural mechanisms of how the RSC constructs spatial representations to code an appropriate route under different sensory cues are unknown. In this study, rat RSC neurons were recorded while rats ran on a treadmill affixed to a motion stage that was displaced along a figure-8-shaped track. The activity of some RSC neurons increased during specific directional displacements, while the activity of other neurons correlated with the running speed on the treadmill regardless of the displacement directions. Elimination of visual cues by turning off the room lights and/or locomotor cues by turning off the treadmill decreased the activity of both groups of neurons. The ensemble activity of the former group of neurons discriminated displacements along the common central path of different routes in the track, even when visual or locomotor cues were eliminated where different spatial representations must be created based on different sensory cues. The present results provide neurophysiological evidence of an RSC involvement in wayfinding under different spatial representations with different sensory cues.

Robust information routing by dorsal subiculum neurons

“…As SUB neurons showed comparable spatial coding with CA1 neurons both at single-cell and population levels, we predict that SUB neurons projecting to regions other than the four that we identified also show strong place coding. Speed information prominently routed to the RSC may interact with visual-locomotion integration in this area (60,61). Trajectory information routed to the NAC may help goal-directed action to obtain a reward, which is thought to be the major function of the NAC (62).…”

The retrosplenial cortex and long-term spatial memory: from the cell to the network

“…Spatial memory tasks can be particularly informative in this respect. But sensory, attentional and mnemonic aspects of tasks must be taken into consideration to properly interpret data obtained from these new neuroscience techniques [e.g., 43 , 55 ]. Alt-text: Box 1 …”

The retrosplenial cortex combines internal and external cues to encode head velocity during navigation

“…To reconcile these data, we identified cortical AHV cells during navigation and, for the first time, determined their response properties to isolated and conjunctive sensory stimuli. We focused on AHV cells in the RSP since it is a cortical region forming part of the head direction network, encodes spatial and movement-related information (28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42)(43), and is critically involved in spatial orientation and self motion-guided navigation (44)(45)(46)(47)(48)(49)(50).…”