the subiculum/CA1 border is located at the middle of the width of the hippocampus in the. At specific days after the surgery for anatomical tracing (anterograde tracing: 15 days, retrograde tracing: 7 days, projection-specific labeling: 20. Anatomically the hippocampus is a limbic system structure deep in temporal lobe of the cerebrum it is crucial for the processing of long-term memory. we provide a detailed description of hippocampal anatomy using a postmortem dataset containing nine specimens of subjects with and without dementia, which underwent a 9.4 T MRI and histological processing. This work deconstructs the complex landscape of subiculum pyramidal cells into spatially segregated subclasses that may be observed, controlled, and interpreted in future experiments. Graphic published in European Neurology 2005 53:171-178. The subiculum is the transition layer from the hippocampus to the parahippocampal gyrus and changes gradually from three to six layers. The polymorphic layer is the alveus and is equivalent to the white matter of the neocortex. We further show that these transcriptomically defined subclasses correspond to differential protein products and can be associated with specific projection targets. The area of the hippocampus proper that is capped by the dentate gyrus is referred to as CA3 (CA for cornu ammonis). These subclasses were mapped onto abutting spatial domains, ultimately producing a complex laminar and columnar organization with heterogeneity across classical dorsal-ventral, proximal-distal, and superficial-deep axes. Using single-cell RNA-seq, we find that the subiculum pyramidal cell population can be deconstructed into eight separable subclasses. Here, we investigated the extent and organizational principles governing pyramidal cell heterogeneity throughout the mouse subiculum. Hippocampal formation refers to a group of structures in the medial temporal lobe that includes the hippocampus, subiculum (as well as the presubiculum and. Accumulating evidence suggests that the subiculum pyramidal cell population may actually be comprised of discrete subclasses. In the hippocampus, the classical pyramidal cell type of the subiculum acts as a primary output, conveying hippocampal signals to a diverse suite of downstream regions.