Polich J. Updating P300: an integrative theory of P3a and P3b

Cognitive Electrophysiology Laboratory, Molecular and Integrative Neurosciences Department, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
Clinical Neurophysiology (Impact Factor: 3.1). 11/2007; 118(10):2128-48. DOI: 10.1016/j.clinph.2007.04.019
Source: PubMed

ABSTRACT The empirical and theoretical development of the P300 event-related brain potential (ERP) is reviewed by considering factors that contribute to its amplitude, latency, and general characteristics. The neuropsychological origins of the P3a and P3b subcomponents are detailed, and how target/standard discrimination difficulty modulates scalp topography is discussed. The neural loci of P3a and P3b generation are outlined, and a cognitive model is proffered: P3a originates from stimulus-driven frontal attention mechanisms during task processing, whereas P3b originates from temporal-parietal activity associated with attention and appears related to subsequent memory processing. Neurotransmitter actions associating P3a to frontal/dopaminergic and P3b to parietal/norepinephrine pathways are highlighted. Neuroinhibition is suggested as an overarching theoretical mechanism for P300, which is elicited when stimulus detection engages memory operations.

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    • "In order to define the P3, we examined difference waveforms (as recommended by [36]) computed by subtracting within task-type (task-repetition prosaccade minus task-switch prosaccade and task-repetition antisaccade minus task-switch antisaccade). Based on previous literature [40] and on an examination of the within-task difference waveforms (Fig. 2a), the P3 was defined as the mean voltage 350 to 400 ms following the fixation cross colour-change on each of the conditional ERP waveforms. Our analysis focused on electrode channel Cz, where the prosaccade difference waveform was maximal (see Fig. 2b). "
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    ABSTRACT: The execution of an antisaccade selectively increases the reaction time (RT) of a subsequent prosaccade (the unidirectional prosaccade switch-cost). To explain this finding, the task-set inertia hypothesis asserts that an antisaccade requires a cognitively mediated non-standard task-set that persists inertially and delays the planning of a subsequent prosaccade. The present study sought to directly test the theoretical tenets of the task-set inertia hypothesis by examining the concurrent behavioural and the event-related brain potential (ERP) data associated with the unidirectional prosaccade switch-cost. Participants pseudo-randomly alternated between pro- and antisaccades while electroencephalography (EEG) data were recorded. As expected, the completion of an antisaccade selectively increased the RT of a subsequent prosaccade, whereas the converse switch did not influence RTs. Thus, the behavioural results demonstrated the unidirectional prosaccade switch-cost. In terms of the ERP findings, we observed a reliable change in the amplitude of the P3 – time-locked to task-instructions – when trials were switched from a prosaccade to an antisaccade; however, no reliable change was observed when switching from an antisaccade to a prosaccade. This is a salient finding because extensive work has shown that the P3 provides a neural index of the task-set required to execute a to-be-completed response. As such, results showing that prosaccades completed after antisaccades exhibited increased RTs in combination with a P3 amplitude comparable to antisaccades provides convergent evidence that the unidirectional prosaccade switch-cost is attributed to the persistent activation of a non-standard antisaccade task-set.
    Behavioural Brain Research 10/2015; DOI:10.1016/j.bbr.2014.10.012 · 3.03 Impact Factor
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    • "BecauseS1reportswerefacilitatedbyinvalidcues,theassociatedincreased amplitudeoftheP3mightreflectthat.InvalidlycuedS1reportscouldthusbecharacterized byincreasedinformationtransfer(orthemonitoringthereofforthepurposeofresponse selection;Verleger,Jaśkowski,&Wascher,2005),andmorecertaintywithregardtothe perceivedcolor(Kok,2001).Inasimilarvein,thereducedP3invalidlycuedtrialsmightbe reflectiveofincreaseddifficulty.Intermsofmemoryoperations,increasedamplitudemight reflectmoresuccessfulconsolidation(Polich,2007).Theseinterpretationsappeartobe equallyfeasibleinthepresentstudyandshowaconsiderabledegreeofconvergence. "
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    ABSTRACT: When two different color stimuli are presented in rapid succession, the resulting percept is sometimes that of a mixture of both colors, due to a perceptual process called color fusion. Although color fusion might seem to occur very early in the visual pathway, and only happens across the briefest of stimulus presentation intervals (< 50 ms), the present study showed that spatial attention can alter the fusion process. In a series of experiments, spatial cues were presented that either validly indicated the location of a pair of (different) color stimuli in successive stimulus arrays, or did not, pointing toward isoluminant gray distractors in the other visual hemifield. Increased color fusion was observed for valid cues across a range of stimulus durations, at the expense of individual color reports. By contrast, perception of repeated, same-color stimulus pairs did not change, suggesting that the enhancement was specific to fusion, not color discrimination per se. Electrophysiological measures furthermore showed that the amplitude of the N1, N2pc, and P3 components of the ERP were differentially modulated during the perception of individual and fused colors, as a function of cueing and stimulus duration. Fusion itself, collapsed across cueing conditions, was reflected uniquely in N1 amplitude. Overall, the results suggest that spatial attention enhances color fusion and decreases competition between stimuli, constituting an adaptive slowdown in service of temporal integration. © 2015 Society for Psychophysiological Research.
    Psychophysiology 09/2015; DOI:10.1111/psyp.12523 · 2.99 Impact Factor
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    • "The head plots provide the topographic distribution of the difference in P3 amplitude for the concussion group relative to the control group. The oddball data is presented only for the target stimulus which elicits the stereotypical P3 component (Polich, 2007), while the flanker data is collapsed across congruent and incongruent stimuli. The 9-electrode site region of interest used for analysis is indicated by the bounding box. "
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    ABSTRACT: Associations between a history of concussion and variability in behavioral and neuroelectric indices of cognition were assessed in college-aged adults with a history of concussion and a healthy control group, in response to a stimulus discrimination task and a more attentionally demanding flanker task. Greater intra-individual variability was observed only for behavioral indices of reaction time in response to the flanker task for those with a history of concussion. An association was also observed between the number of concussions resulting in a loss of consciousness and greater variability of reaction time regardless of the type of task. Relative to neuroelectric measures, a concussive history was associated with smaller P3 amplitude only in response to the flanker task; with no differences between groups observed in response to the oddball task or for intra-individual variability measures. Thus, increased variability associated with a history of concussion appears to be behavior and process specific. The behavioral metrics and functions assessed are important considerations for identifying subtle, yet persistent influences of concussion on cognitive performance. Further, factors such as loss of consciousness associated with a concussive injury may moderate the extent to which these increases in behavioral variability manifest. Thus, the identification of persistent cognitive impairment following concussive injuries necessitates the utilization of appropriate tasks and may be facilitated by going beyond behavioral measures of central tendency. Copyright © 2015. Published by Elsevier B.V.
    International Journal of Psychophysiology 09/2015; DOI:10.1016/j.ijpsycho.2015.08.006 · 2.88 Impact Factor
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