The relevance of context in memory tasks influences the magnitude of hippocampal remapping

The hippocampus is proposed to associate the context of an episode to its content, facilitating contextual discrimination or generalization between memories depending on the situation. While much is known about how context is encoded by neurons in the hippocampus, little is known about how contextual representations are impacted by disparate cognitive demands. Here, we recorded neuron calcium dynamics during a hippocampal-dependent discrimination/generalization task in which the necessity of attending to context was manipulated. Decoding of context was more robust when context was required to solve the task. Context relevance impacted place cell remapping, with the strongest effects observed in fields near reward locations. Other neuron types, such as non-place cells and directional modulated cells, encoded context to the same extent irrespective of whether context was required. These data suggest that when context is behaviorally important, the hippocampus heightens context specificity, primarily through a place-cell-mediated spatiotemporal code.