Differential Proactive Interference Effects in Item Recognition Tasks for Subjects with High and Low Working Memory (WM)-Capacity: An Event-Related fMRI-Study

Abstract:
Neuroimaging findings on prefrontal cortex indicate that this region supports executive control processes such as inhibitory processing of task-irrelevant information. Here we examined whether proactive interference effects in item recognition are task specific or reflect the operation of a general control process. Participants with high and low WM.-capacity performed a letter and an object recognition task. On interference trials the probe did not match a current target, but it was target-set-member and probe on the previous trial. In the letter task interference trials activated a bilateral network along the upper banks of the inferior frontal sulcus and along the banks of inferior precentral sulcus. This activation pattern was more pronounced for low span than for high span subjects. In the object task interference trials led to enhanced activation in the right posterior parietal cortex along the banks of the intraparietal sulcus, with this pattern being more pronounced for high span subjects. These results may reflect the operation of task specific interference suppression mechanisms that are differentially recruited by high span and low span subjects.