A qualitative solution with quantitative potential for the mouse hippocampal cortex flatmap problem

Significance The hippocampal formation (HPF) plays an important role in many cerebral cortical functions, including memory consolidation, spatial navigation, and motivation and emotion. However, the highly convoluted hippocampal layers make visualization of basic spatial relationships unusually difficult. A mouse HPF flatmap was derived qualitatively from a physical model in rat, and to demonstrate its utility this flatmap was used to compare the results of experiments showing the intrahippocampal projections of dentate gyrus mossy fibers with Pcp4 gene expression. A spatial comparison of the rat and mouse HPF is included, and requirements are presented for producing a quantitative computer graphics flatmap that could be used to create a human hippocampal flatmap with accompanying coordinate system that transfers onto the intact brain.