Human brain potential signs of selection by location and frequency in an auditory transient attention situation

Event-related brain potentials (ERPs) were recorded in human subjects receiving tones. Each tone was preceded by a visual cue indicating a to-be-attended feature. In one part of the experiment, subjects had to attend to tones of the indicated frequency, whereas they had to attend to tones delivered at the designated ear in the other part. ERPs to attended tones showed enhanced frontal negativities as compared with ERPs to unattended tones. Additionally, in the location selection condition, a negative difference (Nd) between attended and unattended EPRs occurred between 100 and 200 ms at parietal areas. This parietal Nd seems to be characteristic for transient spatial attention.