I think the hippocampal formation is one of the hardest regions to understand with regard to its overall shape and connection patterns. In the rodent it crosses all three axes in the brain and the orientation of its convoluted layers changes across its septal-temporal axis. Therefore, I am happy to share with you a video that I produced recently, in which I show how the hippocampal formation looks like in 3d. For me it was also a good exercise to produce a video for Youtube, as I am going to produce more in the next weeks.