A connectome is a comprehensive description of the network elements and connections that form the brain (Sporns et al., 2005).
Clear and comprehensive knowledge of anatomical connections in the brain lies at the basis of understanding brain functions. In the connectome featured on this website, the three-dimensional organization of the projection patterns between and within the hippocampal formation, the parahippocampal region and the retrosplenial cortex are visualized in an interactive connectome. All reported projections concerning this system for the rat were collected and stored in a database and visualized in an interactive pdf document.
The second version of our interactive connectome is now freely available for download. This pdf document displays almost 2600 connections in the rat hippocampal – parahippocampal - retrosplenial region, which can all be interactively switched on and off. In addition, three papers and one book chapter are available.
- In the first paper, we highlighted the underexposed aspects of the anatomy of the hippocampal formation and parahippocampal region, together with some of the functional implications of these underexposed connections (van Strien, Cappaert, Witter, 2009).
- In the second paper, we added the retrosplenial cortex to the connectome and discuss the challenges and advantages of connectomes (Sugar et al, 2011).
- In the third paper, we analyzed the HF-PHR connectome using graph analysis (Binicewicz et al, 2016).
- In the book chapter "Hippocampal Formation" in 4th edition of the "The rat nervous system", we despribed the anatomical connectivity of the HF and PHR with sub-cortical and cortical brain areas (Cappaert et al, 2014).
In the summer of 2016, the temporal-lobe project was awarded an Amsterdam Brain and Cognition project grant to continue our databasing efforts and extend our work towards computational modelling. In our new project, entitled “A network approach to unravel the role of the amygdala in memory” we will investigate the modulatory role of the amygdala on learning and memory function in the parahippocampal region (PHR) and hippocampal formation (HF). It is known that the amygdala modulates memory processes by gating information propagation from neocortex through PHR to HF, by its strong connections with the PHR and HF. This may explain why some memories are remembered with great vividness, whereas others are only vaguely remembered. The mechanism by which the amygdala modulates PHR-HF network activity remains unclear. We will investigate this using a computational model that mimics the known anatomical connectivity and simulates the dynamic modulation by rhythmic brain activity. Prof Jaap Murre is a new team member who will supervise our attempt to create meaningful computational models of the networks that we have collated. Prof Menno Witter will be engaged as a visiting professor in this project, funded with an ABC visiting professor grant.