The maintenance of complex visual scenes in working memory may require activation of working memory manipulation circuits in the dlPFC: A preliminary report

Abstract

Past research has shown that the bilateral dorsolateral prefrontal cortices (dlPFC) are implicated in both emotional processing as well as cognitive processing,^1,2,3 in addition to working memory^{4, 5}. Exactly how these disparate processes interact with one another within the dlPFC is less understood. To explore this, we designed a task that looked at working memory performance during fMRI under both emotional and nonemotional conditions, and tested it in this preliminary report. Participants were asked to complete three tasks (letters, neutral images, emotional images) of the Sternberg Sorting Task under one of two trial conditions (sort or maintain). Regions of interest consisted of the left and right dlPFC as defined by brain masks based on NeuroSynth⁶. Results showed a significant main effect of the ‘sort’ condition on reaction speed for all three trial types, as well as a main effect of task type (letters) on accuracy. In addition, a significant interaction was found between trial type (sort) and task type (letters), but not for either of the picture tasks. Although preliminary, these results reveal a discrepancy between BOLD signal and behavioral data, with no significant difference in BOLD activity during image trials being displayed, despite longer response times for every condition. While these initial results show that the dlPFC is implicated in nonemotional cognitive processing, more research is needed to explain the lack of BOLD activation seen here for similar emotionally valanced tasks, possibly indicating the involvement of other brain networks.