Abstract
To characterize intrinsic fluctuations in sustained visual attention, we designed a series of gradual onset continuous performance tasks (GO-CPT) to probe the relationships between reaction time (RT) variability, attention lapses, and brain activity. In Experiment 1, behavioral results confirm that the GO-CPT taxes sustained attention, as errors and RT variability increase over time. Subjects’ attentional state also fluctuates moment-to-moment, with periods of higher RT variability associated with increased likelihood of errors. Using fMRI, these natural fluctuations in performance were linked to the ebb and flow of ongoing activity in the dorsal attention network (DAN) and default mode network (DMN). Specifically, moderate DMN activity accompanies less variable, less error-prone periods of "in the zone" performance. However, when "in the zone," extreme peaks in DMN are predictive of subsequent lapses of attention (errors). In contrast, when "out of the zone," reduced activity in DAN and task-relevant sensory regions predicts errors. In Experiment 2, we explored the additional effects of external distraction on sustained attention. Behavioral results provide confirmatory evidence for intrinsic fluctuations between these two attentional states. Preliminary fMRI results again suggest that lapse precursors vary with attentional state; extreme peaks in DMN (as in Exp. 1), as well as signal increases in task-irrelevant, distractor-sensitive sensory regions are particularly characteristic of errors that occur when "in the zone." Taken together, these findings highlight the neurobehavioral signatures of two distinct attentional states. The first, "in the zone," is a stable, less error-prone, perhaps effortless state, characterized by higher overall DMN activity but during which subjects are at risk of erring if DMN activity rises beyond intermediate levels, or if distractors enter awareness. The second, "out of the zone," is a potentially more effortful state that is not optimal for sustained performance and relies upon activity in task-relevant sensory and control regions.
Meeting abstract presented at VSS 2012