Remembering and imagining differentially engage the hippocampus: a multivariate fMRI investigation.

It has been proposed that imagining the future depends on the ability to retrieve episodic details from past experiences in order to recombine them into novel possible experiences; consequently, the processes of remembering and imagining rely on similar neural substrates, including the hippocampus. We used fMRI and both univariate and multivariate analysis techniques to test this prediction. Unbiased univariate analysis did not reveal differences in the hippocampus between remembering and imagining; however, multivariate analyses revealed evidence that patterns of activity within the hippocampus distinguish between remembering and imagining. Thus, while the hippocampus seems to be involved in both remembering the past and imagining the future, the pattern of activity within the hippocampus distinguishes between these two different tasks.