An event-related brain potential study of cross-modal links in spatial attention between vision and touch

Event-related potential (ERP) evidence for the existence of cross-modal lin ks in endogenous spatial attention between vision and touch was obtained in an experiment where participants had to detect tactile or visual targets o n the attended side and to ignore the irrelevant modality and stimuli on th e unattended side. For visual ERPs, attentional modulations of occipital P1 and N1 components were present when attention was directed both within vis ion and within touch, indicating that links in spatial attention from touch to vision can affect early stages of visual processing. For somatosensory ERPs, attentional negativities starting around 140 ms poststimulus were pre sent at midline and lateral central electrodes when touch was relevant. No attentional somatosensory ERP modulations were present when vision was rele vant and tactile stimuli could be entirely ignored. However, in another tas k condition where responses were also required to infrequent tactile target s regardless of their location, visual-spatial attention modulated somatose nsory ERPs. Unlike vision, touch apparently can be decoupled from attention al orienting within another modality unless it is potentially relevant.