Temporal dynamics of attentional control settings in patients with spatial neglect.

Patients with spatial neglect show disproportionately slow reactions to a contralesional stimulus presented shortly after an ipsilesional cue. We examined whether this attentional bias reflects purely automatic capture of attention by the cue or whether it is contingent on the similarity between cue and target. Patients with spatial neglect reacted to letters presented in the left or right visual field. These target letters were pre-cued by the same letter (similar cue) or a different letter (dissimilar cue) presented 100 or 1000 ms prior to target onset in the same or the opposite visual field. At the short interval, similar and dissimilar ipsilesional cues captured attention comparably and strongly slowed reactions to contralesional targets. In contrast, while similar ipsilesional cues still captured attention at the long interval dissimilar cues ceased to affect performance. In contrast, the different cueing conditions induced only small and insignificant differences in reaction times to ipsilesional targets. These findings suggest that attention of neglect patients is initially captured by all ipsilesional cues in a reflexive, stimulus-driven fashion, but that prolonged attentional capture may only be observed when cues share a property with the target.