Funded Grants

The Time Course and Functional Anatomy of Attentional Control

The ability of human observers to attend to one or a few out of many possible stimuli that are competing for the control of behavior involves complex neural selection mechanisms. The consequences of invoking these mechanisms to selectively attend to events in the world have been well demonstrated in terms of behavioral and cortical responses. Behaviorally, advance knowledge of the form or location of a stimulus enhances the efficiency of processing the cued form or a stimulus presented in the cued location, relative to uncued forms or stimuli presented in uncued locations. Cortically, attention effects are manifest as changes in neural responses to stimuli that are attended as opposed to ignored. However, while the behavioral and cortical responses associated with selective stimulus processing are fairly well characterized, the top-down or "executive" neural mechanisms that control selective attention have not been characterized and are not well understood. Moreover, the neural systems involved in attentional control of selection by object and location specific mechanisms have not been investigated. The focus of the research program outlined in this proposal is to investigate the functional anatomy of attentional control. This proposal will integrate electrophysiological and event related fMRI approaches to studying the neural architecture and mechanisms of attentional control. Three experiments are proposed that manipulate top down selective attention to a target form (Experiment 1), a location (Experiment 2), or both form and location (Experiment 3) via cue stimuli that, more often than not, accurately predict the form, location, or both. The cortical response to cue stimuli will be measured by event related potentials and the corresponding changes in regional cerebral blood flow. Thus, the time course and functional architecture of attentional control systems and their consequence for perceptual processing will be identified.