Spontaneous and Learned States of Preparatory Attentional Control

Individuals regularly experience fluctuations in their readiness to update attentional selections, a phenomenon referred to here as attentional flexibility. These moment-by-moment changes in preparatory control may be attributed to internal factors as well as previous experiences. This dissertation examines the neural systems involved in spontaneous fluctuations of attentional flexibility as well as the degree to which modulations of preparatory control are the learned product of an environment’s statistical regularities. We first identified the neural systems associated with ongoing spontaneous fluctuations in attentional flexibility. Participants shifted covert spatial attention between two rapid serial visual presentation (RSVP) streams of alphanumeric characters in response to visual cues embedded within the attended stream and made target detection behavioral responses. High pretrial activity within a series of default mode network regions was associated with a state of attentional stability, while pretrial increases of activity within the bilateral anterior insula and pre-supplementary motor area/supplementary motor area were associated with increased flexibility. We next tested and found evidence in favor of the role of learning in preparatory attentional control. In one experiment, the stability of previous reinforcement learning influenced future selection strategies. Furthermore, in a series of subsequent experiments using a variant of the RSVP paradigm described above, we manipulated either the likelihood that participants would shift attention or the value associated with shifting attention across temporally- and color-defined contexts. In support of a robust modulatory role of learning, participants demonstrated reduced behavioral shift costs for contexts that were associated with either a high probability of shifting attention or in which shifting was valuable. Furthermore, violations of contextually-learned orienting expectations were associated with elevated activity in the right anterior insula/inferior frontal gyrus, right middle frontal gyrus, and right supplementary motor area, possibly reflecting an overriding of planned orienting commands in light of an unexpected attention cue. Our results indicate that internally generated spontaneous fluctuations in brain activity as well as the regularities of the environment together influence moment-by-moment changes in preparatory attentional control. The current work holds implications for deficits of control in special populations as well as for understanding healthy variation in preparatory control over time