Lateral Thinking: Exploring the Lateral Entorhinal Cortex Projections to the Hippocampus in the Rodent Brain

The lateral entorhinal cortex (LEC) projections to the hippocampus (HC) play a critical role in cognition and have been associated with cognitive impairments related to aging and neurodegenerative disease. This review aims to provide a detailed anatomical description of the LEC-to-HC pathway, based on a review of data collected using neuroanatomical tract tracing techniques. The LEC projects to the HC in a layer-specific manner. Layer II of the LEC provides the primary source of projections to the dentate gyrus (DG), while layer III is the primary source of projections to the subiculum and cornu Ammonis (CA) region. These projections terminate in the molecular layers of the HC and follow a topographical distribution along the dorsolateral-ventromedial axis. Having a clear understanding of the LEC-to-HC pathway is essential background for investigating its functions and alterations due to disease and aging processes.