Abstract
In the present study we examined the effects of preceding stimuli and the stimulation side on the auditory evoked fields and potentials associated with selective attention to the stimuli. In the field responses measured at the contralateral side to the stimulated ear the peak amplitude was smaller when the relevant and preceding stimuli were identical, i. e., at the same ear, than when they were different, i. e., at different ears. Attention effect was observed in the potentials as a negative shift, which was affected strongly by whether the preceding stimulus was identical or not, but little affected by whether the preceding stimulus was attended or not. It is suggested that separating the responses into those whose preceding stimulus is identical to the relevant stimulus and those whose preceding stimulus is different is necessary when attention effect is examined. In the field responses, however, the above attention effect was less clear than in the potentials. Significant differences of the peak latency were observed between the field responses in the right and left hemispheres. The peak latency in the contralateral responses to the stimulated ear was shorter than that in the ipsilateral responses.
