Hippocampal and striatal place-and movement-correlated cell firing was recorded as rats performed place or response tasks in a familiar environment, and then after cue manipulation. In a familiar environment, place field properties did not differ across brain structures or task conditions. Movement correlates were stronger during place task performance only in hippocampal neurons. After cue manipulations, place-and movement-sensitive hippocampal and striatal neurons changed their correlate strength, regardless of behavioral strategy. Thus, for both structures, place-correlated cells may encode spatial context information, whereas movement-correlated cells may represent both egocentric movement and learned behavioral responses. The striking overall similarity between hippocampal and striatal neural responses to context manipulation (regardless of strategy) suggests that these structures operate continuously, and in parallel, during multiple forms of learning.

Rodents are able to rely on self-motion (idiothetic) cues and navigate toward a reference place by path integration. The authors tested the effects of dorsal hippocampal and parietal lesions in a homing task to dissociate the respective roles of the hippocampus and the parietal cortex in path integration. Hippocampal rats exhibited a strong deficit in learning the basic task. Parietal rats displayed a performance impairment as a function of the complexity of their outward paths when the food was placed at varying locations. These results suggest that the parietal cortex plays a specific role in path integration and in the processing of idiothetic information, whereas the hippocampus is involved in the calibration of space used by the path integration system.

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O' Keefe and Nadel (1978) distinguish two paradigms for navigation, the "locale system" for map-based navigation and the "taxon (behavioral orientation) system" for route navigation. This article models the taxon system, the map-based system, and their interaction, and argues that the map-based system involves the interaction of hippocampus and other systems.We relate taxes to the notion of an affordance. Just as a rat may have basic taxes for approaching food or avoiding a bright light, so does it have a wider repertoire of affordances for possible actions associated with immediate sensing of its environment. We propose that affordances are extracted by the rat posterior parietal cortex, which guides action selection by the premotor cortex and is influenced also by hypothalamic drive information.The taxon-affordances model (TAM) for taxon-based determination of movement direction is based on models of frog detour behavior, with expectations of future reward implemented using reinforcement learning. The specification of the direction of movement is refined by current affordances and motivational information to yield an appropriate course of action.The world graph (WG) theory expands the idea of a map by developing the hypothesis that cognitive and motivational states interact. This article describes an implementation of this theory, the WG model. The integrated TAM-WG model then allows us to explain data on the behavior of rats with and without fornix lesions, which disconnect the hippocampus from other neural systems.