Stimulus context determines P3a and P3b

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.

The effect of graded monetary reward on cognitive event-related potentials and behavior in young healthy adults

“…Although this null result may have been influenced by statistical power (and increasing trial or sample size may have revealed higher speed or accuracy as a function of larger monetary reward), our current results point to the role of motivation as a possible modulating factor in the P3's role in reward processing, as reflected by the graded ratings on the subjective interest and excitement scales (45¢>1¢>0¢) (Figure 3). Note that although a parallel graded response was visually discernible in the P3 waveforms (Figure 2), it was not statistically significant (45¢>1¢=0¢), possibly due to low statistical power or the restricted distinctiveness between the low and no reward conditions (see (Comerchero & Polich, 1998) and (Katayama & Polich, 1998) for a positive relationship between P3 amplitude and stimulus distinctiveness). To overcome this limitation, future studies could compare additional or more disparate reward conditions (e.g., $2 vs. $1 vs. 10¢).…”

ERP evidence of impaired central nervous system function in virally suppressed HIV patients on antiretroviral therapy

“…This explanation is in accordance with our interpretation of the HIV-related P2 amplitude reduction. Lastly, task/stimuli differences may also account for the discrepant findings as the relative perceptual distinctiveness among stimuli in the oddball task can determine P3a and P3b amplitudes (Katayama and Polich, 1998). The current study employed a 3-stimulus oddball task with highly discrepant non-target stimuli (sound effect noises) and easily distinguished target and standard stimuli.…”

An ERP study of visual change detection: Effects of magnitude of spatial frequency changes on the change-related posterior positivity

“…For the central LPC, there are at least two possible interpretations: P3a and no-go P300. P3a has been reported to be a frontal/central positivity elicited by several types of infrequent non-target stimuli (e.g., Courchesne et al, 1975;Katayama and Polich, 1998;Squires et al, 1975), and is considered to reflect the attentional shift produced by the mismatch. On the other hand, it has been reported that infrequent non-target stimuli that are easily recognized as "typical" (i.e., not novel) could elicit another types of LPC with maximum amplitudes over the central/parietal area (e.g., Courchesne, 1978;Courchesne et al, 1978;Katayama and Polich, 1996), which is sometimes referred to as no-go P300.…”