Reactivation of context-specific brain regions during retrieval

Abstract

The neural correlates of recollection were examined using event-related functional MRI. We examined how the presence of different visual context information during encoding of target words influenced later recollection for the words presented alone at retrieval. Participants studied words presented with different pictures of faces or scrambled faces on each trial, and on a subsequent scanned recognition test made 'remember', 'know' or 'new' responses to words presented alone. Prior to the study phase, participants performed a localizer task, in which the fusiform face area (FFA) was identified. We compared brain activation patterns for remember and know responses given to words studied with faces as compared to scrambled faces. Though behaviourally participants showed no difference in memory performance depending on encoding trial type, both a group- and individual-based region-of-interest analysis showed increased activation in the functionally-defined FFA for remember responses given to words studied with faces compared to scrambled faces. A regression analysis additionally showed that activation in the right fusiform gyrus increased as the relative recollection benefit for words studied with meaningful (face) compared to non-meaningful (scrambled face) context information increased. Results suggest that context-specific brain regions implicated during encoding are recruited during retrieval, and that the degree to which participants activate context-specific brain regions during retrieval is related to a behavioural benefit in later recollection for target information presented alone.