A re-examination of the retrosplenial contribution to place navigation in the rat

Abstract

Behavioural, electrophysiological, and anatomical evidence suggests that retrosplenial (RS) cortex (areas RSA and RSG) plays a role in spatial navigation. It has been recently suggested that it is damage to the underlying cingulum bundle (CG) (areas CG and IG), and not RS, tht disrupts spatial place learning. I revisited this issue by comparing the rat strains and lesions used in studies that typically report RS deficits, to those used in studies in which no RS deficit is reported. I found both selective RS damage and selective CG damage to disrupt spatial behaviour, suggesting independent contributions to spatial learning and memory from both of these structures. Further, previous failures to find RS deficits are shown to be the result of an inappropriate choice of rat strain for studying normal brain-behaviour relationships combined with a failure to use appropriate testing methods for assessing spatial behaviour.