P3, Decision, and Gestalt Circle: Towards Understanding the Function of the P3b Component of the Event-Related EEG Potential as a Bridge Between Perception and Action

• Applicant: Professor Dr. Rolf Verleger (†)
• Subject Area: General, Cognitive and Mathematical Psychology
• Term: from 2014 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 250692089

The P3 complex of fronto-central P3a and parietal P3b is among the most conspicuous components of the human EEG potential as may be recorded from the scalp. Yet, even after hundreds of studies, the role played by the cortical activation measured as P3b is still not well understood. Classical assumptions are that P3b indicates updating of working memory and is affected by perceptual parameters only, rather than by parameters of behavioral responses. Though falsified since long, these assumptions have still not been replaced by better suggestions. A more recent view holds that P3b is related to the process of decision about what to do in response to perceived stimuli. But the exact nature of this relationship has remained unclear.This project is designed to take this discussion further, above all by scrutinizing the long-neglected relation between P3b and stimulus-response-links. Our recent preliminary studies have led to this working hypothesis: P3b reflects activation of an existing stimulus-response link. P3b will be the larger, the stronger is this stimulus-response link and the less it has presently been primed.The proposed experiments will test and refine this hypothesis through studying effects exerted on P3b by decoupling responses from perception. This will be done in modifications of the two basic paradigms used for measuring P3: the oddball task and the prediction of events. New data-analytic methods will be applied.The final aim is to arrive at a detailed, evidence-based theory of P3b. It is hoped that, by understanding P3b, the integrative cognitive function reflected by P3b, tying perception and action together, will be better understood as well.

• DFG Programme: Research Grants