The oddball effect on P3 disappears when feature relevance or feature-response mappings are unknown

Abstract

The P3b component of human event-related EEG potentials is larger with rare than frequent task-relevant stimuli. In a previous study, this oddball effect was much reduced when stimulus-response (S-R) mappings were still undefined at stimulus presentation (being later provided by response prompts). This reduction may reflect P3b's dependence on transmitted information which might be any relevant information (informational value hypothesis) or, more specifically, information about how to respond (S-R link hypothesis). To distinguish between these two hypotheses and clarify their differences from classical stimulus evaluation hypothesis, we added a second dimension by presenting colored letters, with both colors and letters varying between a rare and a frequent alternative. Response prompts, presented half a second later, were, in different blocks, constant or variable across trials with respect to S-R mapping and with respect to the relevant dimension (color or letter). With partial information, when only one of these two factors is known at stimulus presentation (by being constant across trials), the hypotheses differ in their predictions. The oddball effect will be abolished according to S-R link hypothesis because knowledge of both factors is needed to determine the response, but will only be reduced according to informational value hypothesis and be fully maintained according to stimulus evaluation hypothesis. In fact, oddball effects only occurred with knowledge of both factors, i.e., if both the relevant dimension and its mapping to responses were constant across trials. These results confirm the preeminent role of knowledge about responses for eliciting P3.

The response relevance of visual stimuli modulates the P3 component and the underlying sensorimotor network

“…24 ) and not of the P3, which would be in agreement with the stimulus evaluation account of P3. However, this explanation seems less plausible, given that the present EEG results, as well as the results of the several recent P3 studies conform better to the S-R link activation account 14,15,20,44,84,85 . More plausibly, the S1-R minus S1-I contrast in the fMRI measurement may reflect both P3-and CNV-related activity, and the amplitude increase of both components, P3 and CNV, may have contributed to the observed increase in connections projecting to Figure 7.…”

“…While in some tasks the RT-P3 relationship was linked to stimulus-related processing, in others, like the Simon task and the flanker task, this relationship reflected predominantly response selection processes. Moreover, when experimental procedures are specifically design to examine the relationship between P3 and S-R coupling, the results rather systematically contradict the assumption of the stimulus evaluation account that P3 is not related to response processing 14,15,20,44 . Thus, the assumption seems unsustainable (cf.…”

Stimulus–response learning and expected reward value enhance stimulus cognitive processing: An ERP study

“…Later, Verleger et al. (2018) tested whether the P3b reduction in the oddball paradigm with variable S‐R links was dependent on the informational value of the stimuli or, more specifically, on the information about how to respond. To do so, they manipulated the amount of information contained in the stimuli and again, their association with fixed or variable mappings.…”

Effects of relevance and response frequency on P3b amplitudes: Review of findings and comparison of hypotheses about the process reflected by P3b

“…Its disappearance with simultaneous presentation of the two dimensions was probably due to overlap with a fronto‐central negative component reflecting controlled response selection (Verleger, Baur, et al, ). The mechanism common to those studies appeared to be that the oddball effect became reduced when any information relevant for responding was to be delivered later (Verleger, Grauhan, & Śmigasiewicz, ; Verleger, Hamann, Asanowicz, & Śmigasiewicz, ; Verleger, Keppeler, Sassenhagen, & Śmigasiewicz, ) attesting to the significance of response‐related factors on P3b.…”