Top-down control of visual attention—effects of stimulus modality

Abstract

The aim of the present study was to investigate the effect of stimulus modality on neural activity involved in shifts of visuospatial attention using an event-related brain potential (ERP) technique. Subjects made a voluntary shift of their attention by a warning cue indicating the probable location of a subsequent target stimulus. Auditory verbal cues were used as a warning cue instead of arrow cues. ERPs were analyzed in the time window between the cue and target onset. Behavioral data showed accelerated responses to correctly cued targets and slowed responses to falsely cued targets. Neural activities over the frontal scalp site (500–650 ms latency range), following the activation of temporal–parietal scalp site (latency range of 240–440 ms), were observed during the voluntary attention shift. Both activities were shown as the negative shift of the sustained potential preceding the target stimulus over the hemisphere contralateral to the shifting direction. Furthermore, the sustained negativity (500 ms after cue onset) was larger over the right posterior scalp sites compared to the left homologous sites irrespective of the shift direction. These results are almost consistent with the previous findings in visual cue experiment and indicate that top-down control of visuospatial attention is independent of stimulus modality.