Abstract
Visual working memory plays a key role in the interpolation of temporally occluded external objects by maintaining the representation of the objects. Many fMRI studies have suggested the importance of frontal-parietal network in cognitive tasks. However, little is known about how the prefrontal cortex interacts with parietal cortex during the maintenance period in visual working memory. In this study, we used event-related fMRI to investigate (1) a neural basis of the maintenance period and change detection and (2) functional connectivity of prefrontal cortex with parietal cortex during the maintenance period in visual working memory task for feature-location binding. In terms of the necessity of feature-location binding, we conducted a multiple object permanence tracking task (Saiki, 2003) in three conditions: control (two of four colored targets turned gray), feature (one of four colored targets turned to a novel color), and binding (two of four colored targets were replaced with each other) conditions. Participants were asked to push a response button when they found a target change for each condition. Results showed that brain activation during change detection in the binding condition differed from that in the feature condition. In contrast, during maintenance of visual working memory, binding condition shared a common prefrontal-parietal network with feature condition. Our connectivity analyses revealed a top-down control of prefrontal cortex in the binding condition, but not in the feature condition, during the maintenance period. These results suggest task specific modulation during the maintenance of visual working memory for feature-location binding.
PRESTO from JST and 21st Century COE (D-2 to Kyoto Univ)