Distraction-spanning sustained activity during delayed recognition of locations.

This study investigated the neural systems that may make necessary contributions to the retention in working memory of location information. Particularly controversial in this regard have been the roles of various regions of frontal cortex. The task featured a multi-delay ABCA procedure designed to isolate target-related delay-period activity that would be sustained across intervening, distracting stimuli. This property is necessary for fMRI signal from a brain area to be considered necessary for successful retention of target-related information. Across single-subject analyses and two different group analyses, the Frontal Eye Fields (FEF), Supplementary Eye Fields, and Intraparietal Sulcus were most reliably found to support multi-delay sustained activity, and effects tended to be more robust in left than right hemisphere. Such activity was not found reliably, however, in the Superior Frontal Sulcus anterior to the FEF nor in dorsolateral prefrontal cortex. These results are interpreted as inconsistent with memory systems accounts holding that certain frontal regions are specialized for spatial working memory functions. They are consistent, however, with the view that spatial working memory functions are the product of the operation of spatial selective attention and motor preparatory processes.