Attending to a particular location affects both the processing of stimuli of the attended and of the unattended modality. Using event-related potentials, the present study investigated if similar crossmodal effects exist when attention is oriented to a point in time.
Short (600 ms) and long (1200 ms) empty intervals, marked by a tactile onset and an auditory or tactile offset marker (200 ms long), were presented. In each run, the participants had to attend to one of the two intervals and one of the two modalities and were instructed to respond to infrequent "gap" offset markers (same duration as standard offset markers, but stimulation interrupted in the middle) of this interval and modality.
Event-related potentials to auditory and tactile standard offset markers of attended as compared to unattended intervals were characterized by an enhancement of early negative deflections of the auditory and somatosensory event-related potentials (audition: 100-140 ms; touch: 130-180 ms, 190-230 ms) when audition and touch was attended, respectively (unimodal effects of temporal attention). Similar effects were found for auditory stimuli when touch was task relevant (crossmodal effect of temporal attention).
These results suggest that temporal attention modulates early sensory processing stages both within audition and touch. Moreover, the crossmodal attention effect in the auditory modality provides preliminary evidence that similar links between the modalities, as have been shown for spatial attention, can also affect stimulus processing when attention is focused on a point in time.