title: Preparatory activity in visual cortex indexes distractor suppression during covert spatial orienting.
abstract: The deployment of spatial attention induces retinotopically specific increases in neural activity that occur even before a target stimulus is presented. Although this preparatory activity is thought to prime the attended regions, thereby improving perception and recognition, it is not yet clear whether this activity is a manifestation of signal enhancement at the attended locations or suppression of interference from distracting stimuli (or both). We investigated the functional role of these preparatory shifts by isolating a distractor suppression component of selection. Behavioral data have shown that manipulating the probability that visual distractors will appear modulates distractor suppression without concurrent changes in signal enhancement. In 2 experiments, functional magnetic resonance imaging revealed increased cue-evoked activity in retinotopically specific regions of visual cortex when increased distractor suppression was elicited by a high probability of distractors. This finding directly links cue-evoked preparatory activity in visual cortex with a distractor suppression component of visual selective attention.
authors.affiliation: Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, Maryland 21218, USA.
authors.forename: John T
authors.initials: JT
authors.lastname: Serences
authors.forename: Steven
authors.initials: S
authors.lastname: Yantis
authors.forename: Andrew
authors.initials: A
authors.lastname: Culberson
authors.forename: Edward
authors.initials: E
authors.lastname: Awh
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology*; D001931:Brain Mapping; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009949:Orientation / Q000502:physiology*; D010775:Photic Stimulation; D013028:Space Perception / Q000502:physiology*; D014793:Visual Cortex / Q000502:physiology*