(A) study on neural bases underlying selective long-term memory retrieval

Abstract

Selective retrieval of goal-dependent information from long-term memory is an essential element of everyday life. State-based working memory models, which have recently attracted research attention, propose that attentional selection of mental representations guide ongoing behaviors by retrieving goal-dependent information selectively from long-term memory into working memory. However, how goal-dependent information selectively retrieved from long-term memory is processed in the brain as working memory remains unclear. To directly investigate neural representations during selective long-term memory retrieval, we performed an event-related functional magnetic resonance imaging experiment involving separate learning and selective retrieval sessions. During the learning session, participants memorized scenes in which real-life objects were placed in a natural fashion. The following day, participants in the scanner were asked to selectively retrieve a cued object from the memorized scenes. Independent scans of object and scene perception were taken. Based on multi-voxel pattern analysis, we found that retrieval cue–specific representations tended to be sustained throughout the late phase of selective retrieval in the dorsolateral prefrontal cortex (dlPFC) and angular gyrus (AG). Direct comparisons of neural representations during selective retrieval and those during object perception revealed that AG activity was associated with targeted object information, whereas the dlPFC exhibited a prominent representation of non-targeted objects. Both the dlPFC and AG showed a common representation of retrieved scene information. Object and scene representations were observed mainly during the early phase of selective retrieval and did not persist to the late phase. Different tendencies of the representations unfolded over time, suggesting temporal changes in representations during selective retrieval. We confirmed the representational difference between the early and later phases of selective retrieval, as well as dynamic changes in representations during the early phase compared with the late phase. These results suggest not only differential information processing but temporal dynamics in information processing in the dlPFC and AG during selective retrieval of long-term memory.