The retrosplenial complex as an integration zone between self- and map-based components of spatial navigation and...

Although spatial navigation and declarative memory share overlapping neural mechanisms, they have traditionally been investigated as largely non-overlapping research domains. Recent theories suggest an evolutionary continuity, proposing that systems for navigating physical and mental spaces are linked through shared transformations between self-based (egocentric) and map-based (allocentric) reference frames. Yet, the extent to which these processes rely on common substrates remains unclear. This metanalysis used Activation Likelihood Estimation (ALE) to quantitatively compare fMRI studies on spatial navigation (egocentric or allocentric) and declarative memory (episodic or semantic), assessing convergence across domains. Results revealed extensive overlap, particularly in the retrosplenial complex (posterior cingulate cortex/retrosplenial cortex), which was consistently activated across all four conditions, highlighting its role in integrating and transforming reference frames. Episodic memory overlapped with egocentric navigation in the occipital place area (OPA), the angular gyrus (AG) and the parahippocampal place area (PPA), and with allocentric navigation in the PPA and hippocampus, suggesting flexible recruitment rather than strict mapping. The dorsal anterior cingulate cortex (dACC) emerged as a domain-general hub across memory and allocentric navigation, possibly supporting the regulation of internally vs. externally driven processing. These findings support a shared, large-scale network involving medial temporal, parietal, and cingulo-retrosplenial regions. The retrosplenial complex, anatomically positioned between the hippocampus and the posterior parietal cortex, appears crucial for converting information between egocentric and allocentric coordinates across domains. Future neuroimaging research could clarify how these transformations generalize across spatial and conceptual domains, and how the default mode and salience networks support adaptive cognition.