Within-Channel Selection and Event-Related Potentials During Selective Auditory Attention

Authors


  • This work was partially supported by Grant-in-Aid for Scientific Research (No. 61510067). The Ministry of Education, Science and Culture of Japan.

  • The author thanks Dr. Walter Ritter and two reviewers for their helpful comments on an earlier draft of this article and Kenzo Konishi for discussions about this study.

Address requests for reprints to: Tsunetaka Okita, Department of Science of Behavior. Hyogo College of Medicine, Mukogawa-cho. 1-1, Nishinomiya, Hyogo 663, Japan.

ABSTRACT

Event-related potentials were recorded from subjects who listened selectively to stimuli in one of two input channels (ears). The stimuli were random sequences of five vowels and a tone pip. In separate experimental runs, the difficulty of within-channel selection was manipulated by designating either tone (T), one vowel (1V), or two vowels (2V) as targets. An attention-related negativity (Nd) was observed for attended nontarget vowels irrespective of the target difficulty, but the early, centrally maximal phase of Nd was substantial only for the one-vowel and two-vowel conditions. The Nd between its early and late peaks was significantly larger for the two-vowel condition than for the one-vowel and tone conditions. The 2V minus 1V difference in Nd had a closely similar distribution to the early Nd. These target difficulty effects were interpreted as suggesting that the early Nd recorded in two-selection tasks can be related to a within-channel selection process as well as a between-channel selection process. The more anteriorly distributed, later phase of Nd was suggested to be rather insensitive to the difficulty of the within-channel selection. The nature of the within-channel selection underlying the early Nd was discussed in relation to controlled memory search operations.

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