Effects of attentional filtering demands on preparatory ERPs elicited in a spatial cueing task.

OBJECTIVE We used ERP measures to investigate how attentional filtering requirements affect preparatory attentional control and spatially selective visual processing. METHODS In a spatial cueing experiment, attentional filtering demands were manipulated by presenting task-relevant visual stimuli either in isolation (target-only task) or together with irrelevant adjacent distractors (target-plus-distractors task). ERPs were recorded in response to informative spatial precues, and in response to subsequent visual stimuli at attended and unattended locations. RESULTS The preparatory ADAN component elicited during the cue-target interval was larger and more sustained in the target-plus-distractors task, reflecting the demand of stronger attentional filtering. By contrast, two other preparatory lateralised components (EDAN and LDAP) were unaffected by the attentional filtering demand. Similar enhancements of P1 and N1 components in response to the lateral imperative visual stimuli were observed at cued versus uncued locations, regardless of filtering demand, whereas later attentional-related negativities beyond 200 ms post-stimulus were larger the target-plus-distractor task. CONCLUSIONS Our results implicate that the ADAN component is linked to preparatory top-down control processes involved in the attentional filtering of irrelevant distractors; such filtering also affects later attention-related negativities recorded after the onset of the imperative stimulus. SIGNIFICANCE ERPs can reveal effects of expected attentional filtering of irrelevant distractors on preparatory attentional control processes and spatially selective visual processing.