Figure 1. Approaches for measuring post-encoding reactivation using fMRI.

(A) Data are acquired during a baseline time period (cream box), an encoding experience or learning task (blue box), and a post-experience time period, when reactivation is expected to take place (cream box). To examine the reactivation of multi-voxel representations or patterns, template patterns are defined from the encoding data (center column), which can be activation patterns (A) or functional connectivity patterns (B). Template patterns are then compared to the baseline and post-experience data and their similarity is measured. Reactivation evidence is operationalized as greater levels of similarity between encoding representations and the post-encoding data, as compared to the similarity between encoding patterns and the baseline data. (C) Systems-level interactions can be examined by measuring the level of correlation, or functional connectivity, of the BOLD signal between regions of interest (e.g. hippocampus and cortical regions). Experience-dependent changes in functional connectivity, from pre- to post-experience time periods, serves as an index of systems-level interactions that may be related to memory consolidation.