Stimulus context determines whether non-target stimuli are processed as task-relevant or distractor information

Abstract

Objective: The P300 event-related brain potential (ERP) was elicited using a visual three-stimulus oddball paradigm (standard 0.70, target 0.15, non-target 0.15) to examine how target/standard stimulus context affects non-target processing.Methods: Target/standard discrimination difficulty (easy or difficult) and non-target /target similarity (similar or dissimilar) were manipulated orthogonally. Participants (N = 13) were instructed to respond to each infrequent target stimulus by pressing a button.Results: Target stimuli in all task conditions elicited P3b, which was affected only by the difficulty of target/standard discrimination. When target/standard discrimination was easy, the amplitude of non-target P3 was larger for similar than for dissimilar non-target. In contrast, when target/standard discrimination was difficult, non-target stimuli elicited P3a, the amplitude of which was larger for dissimilar than for similar non-target. Thus, the P300 component for non-target stimuli and the pattern of the effect of target similarity on each P300 component varied as a function of the target/standard stimulus context. Conclusions:The target/standard stimulus context influences the attentional set for stimulus processing such that it determines whether non-target stimuli are processed as task-relevant or distractor information.

P3a from white noise

“…ERP and fMRI studies suggest that frontal attentional mechanisms govern responsivity to contextual novelty (Bledowski et al, 2004a;Kiehl et al, 2001;Kirino et al, 2000;Suwazono et al, 2000), which also imply top-down control (cf. Dien et al, 2004;Ranganath and Rainer, 2003;Sawaki and Katayama, 2006, 2007. The degree of attentional focus, therefore, appears to govern P3a generation whereas the stimulus context contributes to the P3b.…”

“…Katayama and colleagues reported that unique visual stimulus distracter designs (e.g., red squares on either side of the target stimulus) that "capture attention" from the target/standard task produce robust P3a components (Sawaki and Katayama, 2006, 2007. The nature of the distracter disruption has led to the direct assessment of ERP components linked to early stimulus feature evaluation, which engages the selective attention garnered by both stimulus context and task difficulty (Kimura et al, 2008a(Kimura et al, , 2008b(Kimura et al, , 2008cSawaki and Katayama, 2008b).…”

Effects of Novelty on Event-Related Potentials: Aging and Stimulus Replacement

“…Similar late positivity can be recorded for rare nontarget stimuli of the three-stimulus oddball task (frequent 'standard', frequent 'target' and infrequent 'nontarget' stimuli) [20] . P3a appears as an anterior (frontal or central) component in many studies with various paradigms, but in the case of easy target/standard discrimination and nontarget/target similarity in the oddball paradigm, posterior P3a-like components were also recorded [4] . According to recent results, P3a is also elicited by target stimuli [21] .…”

“…The amplitude and scalp distribu-tion of these components are determined by the relationships between the characteristics of the eliciting stimuli and the ongoing cognitive activity. As an example, the P3a ERP component of a task-irrelevant stimulus is larger and has more anterior distribution in demanding discrimination tasks than in easier tasks [2][3][4] .…”

An object cue is more effective than a word in ERP-based detection of deception

“…Rare, task relevant stimuli reliably produce the well-known P300 oddball ERP (Fabiani et al, 1987;Donchin and Coles, 1988;Johnson, 1988;Sawaki and Katayama, 2006) and this occurs for both types of rare stimuli (probes and targets) in this GKT paradigm. Of particular relevance is the oddball response to those rare items (probes) that the person attempts to conceal; in a sense, a recollection process gives the person away due to a memory trace activation making the event significant and salient.…”