Neural activity associated with attention orienting triggered by gaze cues: A study of lateralized ERPs.

This study investigated the electrophysiological (event-related potential, ERP) and behavioral (reaction time, RT) correlates of gaze-cued shifts of visuospatial attention. Participants viewed centrally presented faces with neutral expressions in which eyes looked straight ahead and then shifted to the left or right. Upon movement of the eyes, the facial expression either stayed the same (neutral) or changed to a fearful or happy expression. Participants' task was to identify a probe letter (T or L), which appeared in either the same or the opposite location to the direction of the eye gaze. There was behavioral evidence of a gaze congruency effect, as RTs were faster when the eyes looked toward rather than away from the location of the target. The ERP data indicated the presence of a significant gaze-congruent anterior directing attention negativity (ADAN) at anterior locations (300-500 ms after the onset of the gaze cue). ERP data did not show evidence of initial orienting of attention triggered by gaze cues in the early directing attention negativity (EDAN) at posterior locations (200-300 ms post-cue onset). The gaze cueing effects in the RT and ERP data were not significantly influenced by the emotional expression of the faces. The presence of the ADAN may reflect neural mechanisms that underlie the holding of attention on gazed-at locations.