Understanding how visual attention locks on to a location: Toward a computational model of the N2pc component.

Competing theories regarding the neural mechanism underlying the N2pc suggest that it reflects target enhancement or distractor suppression, but we suggest a different theory. In our study, participants viewed a bilateral dual-stream rapid serial visual presentation (RSVP). Each trial had either one or two targets (T1, T2) presented either in the same or different streams. We found that the N2pc elicited by T1 was not affected by an immediately following T2 at the same location. However, if T2 was on the opposite hemifield, a second N2pc was elicited. These results suggest that the N2pc reflects neural processes involved in localizing a target to initiate the deployment of attention, rather than the sustained enhancement of processing at that location or distractor inhibition. We have created a computational model of a convergent gradient-filter model of attention that reproduces the observed event-related potential traces and makes five testable predictions to be addressed in future work.