Crossmodal links in endogenous and exogenous spatial attention: evidence from event-related brain potential studies

The adaptive control of behaviour in response to relevant external objects and events often requires the selection of information delivered by differe nt sensory systems, but from the same region in external space. This can be facilitated by crossmodal links in the attentional processing of informati on across sensory modalities. Results from recent event-related potential ( ERP) studies are reviewed that investigated mechanisms underlying such cros smodal links in spatial attention between vision, audition and touch. Cross modal attention effects were observed for early modality-specific visual, a uditory, and somatosensory ERP components, indicating that crossmodal links in spatial attention affect sensory-perceptual processes within modality-s pecific cortical regions. ERP modulations prior to target events but sensit ive to the direction of an attentional shift were remarkably similar during anticipatory covert shifts of visual, auditory, or tactile attention. Thes e results suggest that such attentional shifts are mediated by supramodal f rontoparietal control mechanisms. Finally, ER-P evidence is reviewed sugges ting that effects of crossmodal links in endogenous (voluntary) as well as exogenous (involuntary) spatial attention are mediated by a representations of external space which are updated across postural changes. (C) 2001 Else vier Science Ltd. All rights reserved.