Zoom-out attentional impairment in children with autism spectrum disorder.

Autism spectrum disorder (ASD) has long been associated with an inability to experience wholes without full attention to the constituent parts. A zoom-out attentional dysfunction might be partially responsible for this perceptual integration deficit in ASD. In the present study, the efficiency of attentional focusing mechanisms was investigated in children affected by ASD. We measured response latencies to a visual target onset displayed at three eccentricities from the fixation. Attentional resources were focused (zoom-in) or distributed (zoom-out) in the visual field presenting a small (containing only the nearest target eccentricity) or large (containing also the farthest target eccentricity) cue, 100 or 800 msec, before the target onset. Typically developing children, at the short cue-target interval, showed a gradient effect (i.e., latencies are slower at the farthest eccentricity) in the small focusing cue, but not in the large focusing cue condition. These results indicate an efficient zoom-in and zoom-out attentional mechanism. In contrast, children with ASD showed a gradient effect also in the large focusing cue condition, suggesting a specific zoom-out attentional impairment. In addition, the ASD group showed an atypical gradient effect at the long cue-target interval only in the small cue condition, suggesting a prolonged zoom-in and sluggish zoom-out attentional mechanism. This abnormal attentional focusing - probably linked to a dysfunctional top-down feedback from fronto-parietal network to the early visual areas - could contribute to the atypical visual perception associated to individuals with ASD which, in turn, could have consequences in their social-communicative development.