Figure 1: Schematic representation of the overall organization of the entorhinal cortex and its connectivity. (a) Position of the entorhinal cortex and surrounding cortices and hippocampus in the rat left hemisphere. Indicated are the dorsoventral extent of the hippocampus, positions of LEC and MEC, and the approximate position of a representative horizontal section, illustrated in (b). (b) Horizontal section illustrating entorhinal-hippocampal connectivity (see text for more details). (c) and (d) Representation of the topographical arrangement of entorhinal-hippocampal reciprocal connections. A dorsolateral band of entorhinal cortex (magenta) is preferentially connected to the dorsal hippocampus. Increasingly, more ventral and medial bands of entorhinal cortex (purple to blue) are connected to increasingly more ventral levels of the hippocampus. Yellow line in (c) indicates the border between LEC and MEC. (e) Enlarged entorhinal cortex, taken from (c), indicating the main connectivity of different portions of entorhinal cortex. Brain areas preferentially connected to LEC are printed in green, those connected to MEC are in magenta. The color of the arrows indicates preferential connectivity to the dorsolateral-toventromedial bands of entorhinal cortex (magenta or blue, resp.) or that no preferential gradient is present (green).