How is new information converted into a memory trace? Here, we used functional neuroimaging to assess what happens to representations of new events after we first experience them. We found that a particular part of the medial temporal lobe, a brain region known to be critical for intact memory, spontaneously reactivates these events even when we are engaged in unrelated activities. Indeed, the extent to which such automatic reactivation occurs seems directly related to later memory performance. This finding shows that we can now study the dynamics of memory processes for specific experiences during the “offline” periods that follow the initial learning phase.
Figure- Offline reactivation in the entorhinal cortex (ErC). (Left) Hand-drawn anatomical regions of interest (ROIs) shown for one participant. (Right) Reactivation of encoding representations is greater for later recalled (R) than forgotten (F) trials. Bars represent mean ± SE of the condition difference. *P = 0.013, one-tailed paired t test.