Does rehearsal benefit visual memory? The role of semantic associations in the maintenance of intact and phase scrambled scenes
There is a rich behavioral literature on articulatory rehearsal for verbal stimuli, suggesting that rehearsal may facilitate memory, but few studies have examined the benefits for visual stimuli. Neural delay period studies have largely failed to control for the use of maintenance strategies, which make activity patterns during maintenance difficult to interpret. Forty-four participants completed a modified Sternberg Task with either novel scenes (NS) that contained semantic information or
... information or phase-scrambled scenes (SS) that lacked it. Participants were instructed to generate a descriptive label and covertly rehearse (CR) or suppress (AS, i.e., repeat "the") during the delay period. Artifact-corrected delay period activity was compared as a function of maintenance strategy (CR vs. AS) and stimulus type (NS vs. SS). Performance on the working memory task for NS revealed that CR neither provided a short- nor long-term behavioral advantage on the delayed recognition task for CR. Interestingly, when task difficulty increased with SS, there was both a significant short-term as well as a long-term advantage. Comparison of sensor-level delay activity during the maintenance phase for NS and SS revealed two distinct patterns of neural activity for NS; there was greater amplitude in the beta range in the right parietal and centromedial regions. For SS, across all sensors during CR, the higher amplitude was observed in the upper alpha and beta ranges. The results suggest that rehearsal increased subsequent memory with SS but not NS. Moreover, neural modulation during the delay period depends on both task difficulty and maintenance strategy.