Spatiotemporal Analysis of Visual Attention

Abstract

The fact that perception of a visual event can be improved by focusing attention upon its spatial location has been documented in numerous experiments going back more than a century. It is also well established that visual attention can be selectively allocated to nonspatial stimulus features or to entire objects as integrated feature ensembles. In the quest to identify the neural mechanisms that underlie this perceptual selectivity in human observers, neuroimaging methods, including noninvasive recordings of event-related potentials (ERPs) and event-related magnetic fields (ERMFs), have provided valuable insights. Contributions from the ERP and ERMF methodologies have been particularly important for revealing the time course and rapid coordination of the underlying selection processes. The ever-expanding body of research in this field has made it abundantly clear that visual attention does not rely upon a unitary neural mechanism, but instead that multiple selection processes cooperate in a flexible manner to guarantee the adaptability of attention to a wide range of circumstances. Here we outline some of the principles underlying the flexible coordination of space-, feature-, and object-based selection processes that have emerged from recent studies, with particular emphasis on the contributions of ERP and ERMF recordings in human observers.