title: The P4pc: an electrophysiological marker of attentional disengagement?
abstract: The processing of successive targets requires that attention be engaged and disengaged. Whereas attentional engagement can be studied by means of the N2pc component of the event-related potential (ERP), no ERP component has been linked to attentional disengagement. Here, we report the finding of such a component using an RSVP paradigm with multiple, successive targets and with a spatial-cuing paradigm. In both experiments, disengagement of attention was necessary to attend to subsequent targets. A distinct waveform following the N2pc, which we call the P4pc (Positivity 400 ms post-target posterior contralateral), was found. The P4pc was found when a lateralized cue indicated that attention would be needed for the processing of a target at either the same or a different location as the cue, but not when only the cue was to be responded to, indicating that the need to disengage attention is a prerequisite for the P4pc to occur. We expect the P4pc to provide a valuable addition to the set of electrophysiological measures used to study the dynamics and mechanisms of visual attention and visual search.
authors.affiliation: Experimental Psychology, University of Groningen, Groningen, The Netherlands. p.toffanin@rug.nl
authors.forename: Paolo
authors.initials: P
authors.lastname: Toffanin
authors.forename: Ritske
authors.initials: R
authors.lastname: de Jong
authors.forename: Addie
authors.initials: A
authors.lastname: Johnson
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001288:Attention / Q000502:physiology*; D004569:Electroencephalography / Q000379:methods; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008297:Male; D010775:Photic Stimulation / Q000379:methods; D011930:Reaction Time / Q000502:physiology; D055815:Young Adult