Many researchers that study the hippocampus have made their own attempt at drawing a diagram of the connections in the hippocampus. When attempting this, one soon discovers that it is challenging to create a diagram that accurately resembles the literature. Natalie Cappaert and Niels van Strien too started this project as an attempt to increase their own understanding of the network. Soon they discovered that creating a diagram of the hippocampal - parahippocampal connections with all its topological detail is indeed a complex task. They started in 2005 and worked together with an expert in the field, Prof. Dr. Menno P. Witter. Although many additions are conceivable, the first version of their interactive diagram is now finalized and available for download. It displays almost 1600 connections in the rat hippocampal - parahippocampal region, which can all be interactively switched on and off. In addition, a Nature Reviews Neuroscience paper is available in which the anatomy is reviewed with an emphasis on underexposed connections in the network, and some of the functional implications of these connections.

In order to comprehend the unique functional contribution of each parahippocampal - hippocampal sub-region, detailed anatomical knowledge is of pivotal importance. In the diagram featured on this website, they attempted to visualize the three-dimensional organization of the projection patterns between and within the parahippocampal region and hippocampal formation. All literature concerning projections of this system for the rat (see References) was collected and reported projections were stored in a database. Over the years, the nomenclature has changed and when necessary reported results were translated into a common frame of reference using this table). Subsequently, almost 1600 projections were drawn between all subdivisions of the HF and PHR with as much topographical detail as current knowledge permits.