| Using event-related brain potentials (ERPs) as measures of attention, this study examines how stressing the attention system via the visual modality affects attentional processing in the auditory modality. The three main purposes of this study were to examine the changes in N100, early- and late-Nd, and the T-Complex, and their relationship to attentional processing. A dual-task paradigm was used consisting of the Posner covert attention visual-cueing paradigm as the primary task, and the dichotic listening task as the secondary task. The results showed no effect of attention on N100. Late-Nd amplitude decreased with the introduction of the visual task while early-Nd remained unaffected. This decrease was attributed to an intermodal interference with the maintenance of an attentional trace process from the dichotic listening task due to the resource demands required by a constant encoding process from the visual task. The T-Complex component Tc exhibited an attention effect when pooled across conditions, showing a larger amplitude in the attended versus the unattended waveforms. This attention effect was attributed to a reflection of an early-Nd effect expressed at the temporal electrodes and it is suggested that the attention related T-Complex may be more closely related to early-Nd rather than to N100. |
