Using traditional (i.e., “slow-rate”) event-related fMRI, we have previously demonstrated that largely overlapping portions of the fronto-parietal attentional network are engaged by voluntary shifts of attention in object-centered as well as viewer-centered visual frames of reference, and that bilateral portions of superior temporal cortex are more strongly engaged when these attentional shifts occur within object-centered space, relative to viewer-centered space. This previous work employed relatively long intervals between the attention-directing cues and subsequent visual targets (i.e., cue-target intervals of 7.5 seconds). Here, we attempt to replicate these findings using rapid, event-related functional MRI at 1.5T. Participants were cued to attend to locations defined within viewer- or object-centered space and made form discriminations on targets subsequently presented at those locations. Brain activity associated specifically with attention-directing cues was analyzed to determine whether partially separable brain systems mediate attentional orienting in different visual frames of reference. The current study uses timing parameters that are more consistent with the majority of published spatial cueing paradigms (i.e., cue-target intervals of 1-2 seconds), and therefore allows more direct comparison of activations with the extant literature. In addition, the shorter cue-target interval reduces demands on working memory operations, allowing us to characterize more accurately the activated regions as involved in attentional control, rather than working memory. Results are discussed with respect to neuropsychological models of reference frame effects in visuospatial attention.


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