navigation, in a manner that, at least partly, must rely on external cues32. During spontaneous recall, the direction of flow is from the hippocampus to the entorhinal cortex43,100 but it is not known how this reversed flow is used during navigation. Yet on account of the postulated similar algorithms governing navigation and memory, one may speculate that once a path in the maze is learned, the sequential activation of hippocampal neurons can be temporally disengaged from external landmarks, as when driving a car to work on a long-practiced route. This raises the question of whether the direction of neuronal activity in the entorhinal cortex–hippocampus flips back and forth during navigation.We become aware of our recollections only after segments of the neuronal sequences enter the working memory system. Does this conscious operation require only the prefrontal cortex, or are interactions with the rest of the cerebral cortex also needed?
