Heterogeneity in Human Retrosplenial Cortex: A Review of Function and Connectivity
Retrosplenial cortex (RSC) is an important information hub in the brain and several mental disorders demonstrate RSC dysfunction, but its role is still largely unclear. Although researchers in many cognitive domains have recognized the importance of RSC, a broader synthesis of RSC function across cognitive domains is lacking. This review examines human RSC function across several cognitive domains, considering both specific cognitive functions and the RSC subregions in which that function occurs. Overall, this review found evidence for a functional gradient across the anterior-posterior axis of RSC involving several cognitive domains. Within the cognitive realm of navigation, RSC is important for path integration (including head direction), landmark processing, and the transformation between viewpoints. The related cognitive domain of scene processing encompasses information about place recognition and spatial context. Both navigation and scene processing are localized to more posterior subregions of RSC. Episodic memory (particularly episodic recall), mental imagery, and self-referential processing tend to be supported by anterior portions of RSC. The heterogeneity of RSC function is consistent with RSC anatomy and connectivity found in animal models. Finally, this review examines several common themes that emerged, including mental imagery and self-referential processing. Both the functional heterogeneity and the common themes of RSC function could provide new avenues for research and insight into the numerous mental disorders characterized by RSC dysfunction.