Attention to motion enhances processing of both visual and auditory stimuli: an event-related potential study

The present event-related potential (ERP) study investigated whether attending to a particular direction of motion similarly enhances the processing of auditory and visual stimuli. ERPs were recorded while participants perceived horizontally moving visual and auditory stimuli. Attention was manipulated by asking participants to detect an infrequent target stimulus that was of a specified modality (either visual or auditory) and that moved in a specified direction (either leftward or rightward). Stimuli moving in the attended direction elicited ERPs that were more negative than ERPs to stimuli moving in the unattended direction. This difference started around 140 ms post stimulus onset for visual and around 120 ms for auditory stimuli. The auditory effect had a frontal scalp topography, whereas the visual effect was distributed parieto-occipitally. Later parts of the difference waves were maximal at centro-parietal electrodes for both modalities. Crossmodal effects of attention to motion from one modality to the other could not be detected. The results are discussed with regard to hierarchical models of attention.