Abstract
Previous studies have revealed transient reconfiguration signals in the superior parietal lobule (SPL) that are time-locked to shifts of attention between spatial locations, features, or sensory modalities (Yantis et al., 2002; Liu et al., 2004; Shomstein & Yantis, 2004). We investigated the generality of this mechanism for congitive control during non-perceptual shifts in task-sets. Subjects monitored one of two RSVP streams for letter cues and digit targets (embedded in other distractor letters) to perform a magnitude or parity task. The four letter cues instructed subjects to (a) hold attention at the current location, (b) shift attention to the location in the opposite visual field, (c) hold the current task-set, or (d) switch to the other task-set. Brain regions associated with attention shifts and task-set switches were identified and compared. Both distinct and common patterns of activation were observed. For example, bilateral posterior intraparietal sulcus (IPS) exhibited transient increases in activity duirng attention shifts but not task switches. However, medial superior parietal lobule produced transient signals for both attention shifts and task switches. This result suggests that these two types of cognitive control may recruit domain-specific as well as domain-independent cortical mechanisms for cognitive reconfiguration.