Selective visual attention is thought to facilitate goal-directed behavior by biasing the system in advance to favor certain stimuli over others, resulting in their selective processing. The aim of the present study was to gain more insight into the link between control processes that induce a spatial attention bias, target selection processes and speed of responding. To this end, participants performed a spatial cueing task while their brain activity was recorded using EEG. In this task, cues either validly or invalidly predicted the location (left or right) of a forthcoming imperative stimulus or provided no information regarding its location. Cues directing attention in space elicited greater positivity over fronto-central and contralateral posterior scalp regions than non-informative cues starting around 320 ms post cue. Targets appearing at attended vs. unattended locations evoked larger P1 and N1 components, indicating enhanced perceptual processing. Interestingly, detection of targets was fastest in trials with most cue-evoked posterior positivity and in trials with largest target-evoked N1 amplitude. Importantly, the greater the difference in cue-evoked posterior positivity between fast and slow trials, the greater the difference in target-evoked N1 amplitude between fast and slow trials was. Together these findings support neurobiological models of attention that postulate that preparatory attention to a particular location in space can bias the system in advance to favor stimuli presented at the attended location, resulting in a modulation of perceptual processing of incoming stimuli and facilitated goal-directed behavior. (Author/publisher)
Samenvatting