Intermodal spatial attention differs between vision and audition: An event related potential analysis

Analyzed timing differences between intra- and intermodal attention. The question of whether or not location selection processes also take place within unattended modalities was explored. Scalp potential distributions for both intra- and intermodal attention to visual as well as auditory stimuli are described. Whether or not stimuli presented to a nonattended modality distract attention from processing stimuli presented to the attended modality was analyzed. 19 18-41 yr olds attended to a combination of stimulus modality and location. Intermodal attention was measured by comparing event-related potentials (ERPs) to visual and auditory stimuli when the modality was relevant or irrelevant, while intramodal attention was measured by comparing ERPs to visual and auditory stimuli presented at relevant and irrelevant spatial locations. Intramodal spatial attention was expressed differently in visual and auditory ERPs. When vision was relevant, spatial attention showed a contralateral enhancement of posterior NI and P2 components and enhancement of parietal P3. When audition was relevant, spatial attention showed a biphasic fronto-central negativity. The same effects were also present in ERPs to stimuli that were presented in the irrelevant modality.