Stimulus context determines P3a and P3b

Author(s): Polich, J.

Journal/Book: Psychophysiology. 1998; 35: 40 West 20TH Street, New York, NY 10011-4211. Cambridge Univ Press. 23-33.

Abstract: P300 differences for target (.10), nontarget (.10), and standard tones (.80) were assessed using a three-stimulus oddball paradigm in which participants responded only to the target (n = 12). Target/standard (easy or difficult) and nontarget/standard (large or small) pitch differences were manipulated orthogonally. In all conditions, target tones elicited a parietal P300, which was affected only by the target/standard discrimination ease. Nontarget in the easy/large and difficult/small conditions elicited a parietal but smaller P300 than the target but in the easy/small condition elicited similar ERPs to the standard. However, nontarget stimuli in the difficult/large condition elicited an anterior maximum and earlier P300 (P3a) component. The findings suggest that target P300s are not influenced by the nontarget stimulus configuration, whereas the nontarget P300 outcomes are determined directly by the stimulus context. The theoretical implications are discussed.

Note: Article Katayama J, Hokkaido Univ, Fac Educ, Sapporo, Hokkaido 060, JAPAN

Keyword(s): P300; P3a; P3b; event-related potential (ERP); task difficulty; three-tone oddball paradigm; EVENT-RELATED POTENTIALS; LATE ERP COMPONENTS; CROSSMODAL DIVIDED ATTENTION; COGNITIVE BRAIN POTENTIALS; CHOICE REACTION TASKS; AGE-RELATED-CHANGES; AUDITORY-STIMULI; SOMATOSENSORY STIMULI; RESPONSE PRODUCTION; SCALP DISTRIBUTION

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