Functional neuroimaging studies have revealed that a bilateral fronto-parietal network is critically involved in the top-down deployment of visuospatial attention in response to endogenous visual cues (e.g., an arrow). Further, a right temporal-parietal region (rTPJ) is engaged for reorienting attention to targets when prior cue information incorrectly predicts target location. Numerous behavioral studies have shown that reorienting attention to an invalidly cued location within an object is faster than reorienting attention to an equidistant location within a different object. These “object-based” effects have been demonstrated repeatedly for reorienting shifts of attention in response to invalidly cued targets, suggesting the involvement of rTPJ. It is unclear, however, whether similar object-based effects are associated with top-down attentional control mechanisms, particularly the fronto-parietal network. In the current study, we provide evidence for distinct, object-based effects associated with the initial deployment of attention in response to valid endogenous cues. Using a modified double-rectangle paradigm (Egly, Driver, & Rafal, 1994), participants performed a simple detection task with predictive (75% valid) pre-cues. Initial shifts of attention could either be within an attended object, or to an equidistant location on a different object. This allowed us to compare initial (top-down) as well as reorienting (bottom-up) shifts of attention to locations either within or between objects. Object-based effects were observed for initial (top-down) shifts of attention in response to valid endogenous cues, suggesting that the fronto-parietal attention control network, like the rTPJ, may also respect such distinctions. Results are discussed in terms of behavioral and neuronal distinctions between top-down and bottom-up control systems.


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