Can attention be directed to opposite locations in different modalities? An ERP study

Objectives: An event-related brain potential (ERP) study investigated whether spatially selective processing in vision and audition is controlled by a single supramodal system or by independent modality-specific systems. Methods: Event-related brain potentials were recorded in response to visual and auditory stimuli at attended and unattended locations. In the 'Attend Same' condition, attention was directed to a single location in both modalities, while in the 'Attend Opposite' condition, visual and auditory attention had to be directed into opposite directions. Results: Sensory-specific effects of attention on visual and auditory ERPs reflecting attentional modulations of perceptual processing were obtained in the 'Attend Same' condition, but not the 'Attend Opposite' condition. Beyond 200 ms post-stimulus, attentional ERP effects were also found in the 'Attend Opposite' condition. Conclusion: Results are inconsistent with the view that spatially selective processing is controlled by independent modality-specific systems. Effects of spatial attention on visual and auditory perceptual processing an closely linked, suggesting the existence of a supramodal attentional control system. At post-perceptual levels, attentional control may be more flexible. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.