Hippocampal Revolutions

New concepts build on research on the rodent hippocampus, but go beyond that to understand how the hippocampal system operates in primates including humans. First, in rodents place cells and entorhinal cortex grid cells represent the place where the individual is located, but in primates including humans, many hippocampal system neurons respond to spatial view, to where the individual looks in space. Second, rodent navigation is described from place to place, but in primates including humans, the highly developed foveal visual system and hippocampal spatial view cells allow use of visual landmarks for completely different navigational strategies. Third, research in primates including humans emphasises functions of the hippocampus in episodic memory, rather than a cognitive map. Fourth, in humans the ventromedial cortical visual pathway for scenes, the ventrolateral cortical visual pathway for faces and objects, and the orbitofrontal cortex for reward provide the hippocampus with its inputs and outputs. Fifth, these discoveries in primates including humans fit with the computational theory of hippocampal CA3 circuitry for episodic memory. Sixth, in humans, the major connectivity from the hippocampal episodic memory system to the anterior temporal lobe semantic cortical regions is stimulating new approaches to how the hippocampus helps to build semantic memories.