title: Blocked versus randomized presentation modes differentially modulate feedback-related negativity and P3b amplitudes.
abstract: OBJECTIVE
  Electrophysiological studies on feedback processing typically use a wide range of feedback stimuli which might not always be comparable. The current study investigated whether two indicators of feedback processing - feedback-related negativity (FRN) and P3b - differ for feedback stimuli with explicit (facial expressions) or assigned valence information (symbols). In addition, we assessed whether presenting feedback in either a trial-by-trial or a block-wise fashion affected these ERPs.
  
  
  METHODS
  EEG was recorded in three experiments while participants performed a time estimation task and received two different types of performance feedback.
  
  
  RESULTS
  Only P3b amplitudes varied consistently in response to feedback type for both presentation types. Moreover, the blocked feedback type presentation yielded more distinct FRN peaks, higher effect sizes, and a significant relation between FRN amplitudes and behavioral task performance measures.
  
  
  CONCLUSIONS
  Both stimulus type and presentation mode may provoke systematic changes in feedback-related ERPs. The current findings point at important potential confounds that need to be controlled for when designing FRN or P3b studies.
  
  
  CONCLUSIONS
  Studies investigating P3b amplitudes using mixed types of stimuli have to be interpreted with caution. Furthermore, we suggest implementing a blocked presentation format when presenting different feedback types within the same experiment.
authors.affiliation: Social, Cognitive and Affective Neuroscience Unit, Department of Basic Psychological Research and Research Methods, Faculty of Psychology, University of Vienna, Liebiggasse 5, A-1010 Vienna, Austria. Electronic address: daniela.pfabigan@univie.ac.at.
authors.forename: Daniela M
authors.initials: DM
authors.lastname: Pfabigan
authors.affiliation: Social, Cognitive and Affective Neuroscience Unit, Department of Basic Psychological Research and Research Methods, Faculty of Psychology, University of Vienna, Liebiggasse 5, A-1010 Vienna, Austria.
authors.forename: Michael
authors.initials: M
authors.lastname: Zeiler
authors.affiliation: Social, Cognitive and Affective Neuroscience Unit, Department of Basic Psychological Research and Research Methods, Faculty of Psychology, University of Vienna, Liebiggasse 5, A-1010 Vienna, Austria.
authors.forename: Claus
authors.initials: C
authors.lastname: Lamm
authors.affiliation: Social, Cognitive and Affective Neuroscience Unit, Department of Basic Psychological Research and Research Methods, Faculty of Psychology, University of Vienna, Liebiggasse 5, A-1010 Vienna, Austria; Department of Psychology, Faculty of Social Sciences, University of Gothenburg, Haraldsgatan 1, SE-40530 Gothenburg, Sweden.
authors.forename: Uta
authors.initials: U
authors.lastname: Sailer
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology*; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology*; D005246:Feedback; D005260:Female; D006801:Humans; D008297:Male; D010775:Photic Stimulation / Q000379:methods*; D055815:Young Adult
keywords: FRN; Feedback stimulus characteristics; P3b; Presentation mode