Parietal P3 Research Articles

Cognitive-motor interference in the wild: Assessing the effects of movement complexity on task switching using mobile EEG.

Adaptively changing between different tasks while in locomotion is a fundamental prerequisite of modern daily life. The cognitive processes underlying dual tasking have been investigated extensively using EEG. Due to technological restrictions, however, this was not possible for dual-task scenarios including locomotion. With new technological opportunities, this became possible and cognitive-motor interference can be studied, even in outside-the-lab environments. In the present study, participants carried out a cognitive-motor interference task as they responded to cued, auditory task-switch stimuli while performing locomotive tasks with increasing complexity (standing, walking, traversing an obstacle course). We observed increased subjective workload ratings as well as decreased behavioural performance for increased movement complexity and cognitive task difficulty. A higher movement load went along with a decrease of parietal P2, N2 and P3 amplitudes and frontal Theta power. A higher cognitive load, on the other hand, was reflected by decreased frontal CNV amplitudes. Additionally, a connectivity analysis using inter-site phase coherence revealed that higher movement as well as cognitive task difficulty had an impairing effect on fronto-parietal connectivity. In conclusion, subjective ratings, behavioural performance and electrophysiological results indicate that less cognitive resources were available to be deployed towards the execution of the cognitive task when in locomotion compared to standing still. Connectivity results also show a scarcity of attentional resources when switching a task during the highest movement complexity condition. Summarized, all findings indicate a central role of attentional control regarding cognitive-motor dual tasking and an inherent limitation of cognitive resources.

Response Activation and Inhibition in Patients With Prolactinomas: An Electrophysiological Study.

Impairment of executive function has been reported in patients with prolactinomas. However, few studies have investigated the electrophysiological mechanisms of response activation and response inhibition in these patients. In this study, we employ an event-related potentials (ERPs) technique to quantitatively assess response activation and inhibition before and after the surgical treatment of prolactinomas. A 64-electrode electroencephalogram (EEG) skullcap was used to record the brain activity in 20 pre-operative patients, 20 follow-up post-operative patients, and 20 healthy controls (HCs) while performing the visual Go/Nogo task. As expected, we identified P300 across all study populations that could reflect response activation and inhibition. Across the three groups, the Nogo stimuli evoked larger frontal-central P300 than the Go stimuli did. In contrast, the Go trials elicited larger parietal P300 than the Nogo trials did. The peak latency of P300 was significantly delayed in both the pre-operative and the post-operative groups compared to the HCs. The amplitude of P300 in both the Go and the Nogo conditions was significantly decreased in the pre-operative patients compared with that of the HCs. At 6 months post-operatively, the prolactinoma patients showed an increase in amplitude of P300 during both the Go and the Nogo tasks. These findings indicate that the prolactinoma patients suffer from deficits in response activation and inhibition, which could be improved by surgical treatment.

The Effect of Transcutaneous Auricular Vagal Nerve Stimulation (taVNS) on P3 Event-Related Potentials during a Bayesian Oddball Task.

Transcutaneous auricular Vagal Nerve Stimulation (taVNS) is a non-invasive brain stimulation technique associated with possible modulation of norepinephrinergic (NE) activity. NE is suspected to contribute to generation of the P3 event-related potential. Recent evidence has produced equivocal evidence whether taVNS influences the P3 in healthy individuals during oddball tasks. We examined the effect of taVNS on P3 amplitudes using a novel visual Bayesian oddball task, which presented 200 sequences of three stimuli. The three consecutive stimuli in each sequence are labelled Draw 1, Draw 2 and Draw 3. In total, 47 Subjects completed this visual Bayesian oddball task under randomised sham and active taVNS stimulation in parallel with an electroencephalographic (EEG) recording. We conducted exploratory analyses of the effect of taVNS on P3 amplitudes separately for Draws. We found typical oddball effects on P3 amplitudes at Draws 1 and 2, but not Draw 3. At Draw 2, the oddball effect was enhanced during active compared to sham taVNS stimulation. These data provide evidence that taVNS influences parietal P3 amplitudes under specific circumstances. Only P3 amplitudes at Draw 2 were affected, which may relate to closure of Bayesian inference after Draw 2. Our findings seemingly support previously reported links between taVNS and the NE system.

ERP indices of an orientation-dependent recognition of the human body schema

While it is well-established that the face perception is orientation-dependent, less evidence has been provided on the effects of the orientation on the body schema processing and related attentive mechanisms. Poorer performance in same/different judgment tasks and increased occipito-temporal N1 response to the inverted (vs. upright) body schema seem to hint at an orientation-dependent perceptual mechanism. The present electrophysiological study investigated the role of attentive selection processes required to recognize the inverted (vs. upright) body schema by means of the event-related potentials (ERP). 320 different images depicting body shapes (wooden dummies) as opposed to random structures of cubes were created in 3D graphics. Thirty-two right-handed participants were presented with the stimuli in an upright and inverted orientation. They were required to alternatively recognize one of the two categories of stimuli (by button press) regardless of the orientation, during EEG recording. The body inversion led to increased reaction times during body schema recognition. A slower anterior N2, larger N1, Selection Negativity (SN), and increased parietal P300 components were elicited by the perception of the inverted body schema. Slower stimulus processing and increased attention allocation were associated with the processing of the inverted body schema. The swLORETA source reconstruction (in the SN time window) showed enhanced engagement of prefrontal, limbic, and temporal regions during the perception of the inverted body schema. At the same time, the cubes’ orientation did not affect ERP amplitudes. Overall, these pieces of evidence seem to suggest a crucial role of the upright orientation in the visual recognition of the human body schema.

Attention please: ERP evidence for prime-target resource competition in the neutral-target variant of affective priming

Using event-related potentials we examined the mechanisms that underlie the influence of affective context information on evaluative judgments in affective priming (AP). Participants (N = 44) evaluated a priori neutral target ideographs that were preceded by 800-ms negative, neutral or positive prime pictures. We observed a significant AP effect (APE), with more positive target ratings for targets following positive versus negative primes, with neutral primes lying in between. A greater individual APE was associated with increased attention for the primes, indicated by larger amplitudes of parietal positive slow wave (PSW) and more pronounced prime affect discrimination mirrored in affect-specific variations of parieto-occipital prime P1 and parietal prime P2, P300, and PSW amplitudes. This confirms previous theoretical and empirical work suggesting that the size of the APE critically depends on the extent of prime-elicited affective activation. Furthermore, a greater individual APE was related to generally reduced depth of target processing as mirrored in smaller overall amplitudes of attention-sensitive target-related P1, P2, P300, and PSW. In addition, in the total sample P2, P300, and PSW were smaller for targets following AP eliciting, attention-capturing emotional, as compared to neutral primes. Based on the observed coincidence of increased processing of affective versus neutral primes, and specifically reduced processing of those targets that followed affective primes, we propose prime-target resource competition as an additional, not yet described process contributing to AP in the neutral-target paradigm.

Preceding stimulus sequence effects on the oddball-P300 in young and healthy older adults.

The present study examined the mechanisms underlying stimulus sequence effects on the parietal P300 and frontal P3a elicited by infrequent targets in an oddball paradigm and compared these effects between young and older adults. Fifty young and 50 healthy older adults completed a simple visual oddball task including an infrequent (20%) target stimulus. A temporo-spatial principal component (PCA) analysis was used to disentangle the parietal P300 and frontal P3a from overlapping ERP components. The typical age-related anterior-shift of the P300 was, according to the PCA, due to a disproportionately large contribution of a frontal P3a in older adults. Up to about five successive standards preceding a target, the results replicated the typical increase in parietal P300 amplitude to targets with increases in preceding standards. A novel finding was that with further increases in preceding standards, P300 amplitude to targets gradually decreased. This pattern is consistent with a combination of relatively automatic, temporary expectations and higher level, conscious expectations driving P300 sequential effects, with different dynamics over the course of successively presented standards. However, an expectancy-based account of these sequential effects was challenged by an analogous analysis of RTs. Sequential effects on the frontal P3a differed from the parietal P300: The P3a was largest when a target followed another target and continually decreased with the number of intervening standards. Notably, sequential effects were strikingly similar for young and older adults, and implications for the functional significance of morphological changes in P300 due to aging are discussed.

Evidence for parietal reward prediction errors using great grand average meta-analysis

As a basic principle within the economics of decision-making, reinforcement learning dictates that individuals strive to repeat behaviour that elicits reward, and avoid behaviour that elicits punishment. Neuroeconomics aims to measure reinforcement learning physically in the brain through the use of reward prediction errors: the difference between expected outcome value and actual outcome value following decision-making behaviour. Two electrophysiological components, the frontocentral feedback-related negativity and the more parietal P3, are implicated in outcome processing, but whether these components encode a reward prediction error has been unclear. A source of the unclear literature is likely to be inconsistent quantification of the components. A recent meta-analysis that directly quantified published waveforms rather than using reported effect sizes found strong evidence that the feedback-related negativity encodes a reward prediction error. In the current study, such a meta-analysis was performed on parietal waveforms to establish whether the P3, or parietal areas generally, are sensitive to reward prediction errors. A strong effect was found, both of reward prediction error encoding and simple valence sensitivity at a latency associated with the P3.

Feature Overlap and Relevance Determine Sequential Modulations in the Simon Task

Abstract. Subjects usually respond faster and more accurate in trials in which the response location corresponds to a task-irrelevant stimulus location compared to when not. Previous research has shown, that this so-called Simon effect is reduced after non-corresponding compared to after corresponding trials. As of now it is yet unclear what exact mechanisms drive such sequential modulations. One theory assumes a conflict adaptation mechanism that decreases the influence of incongruent information after non-corresponding trials via increased cognitive control. However, other authors claim that feature integration processes may be the underlying mechanism as the amount of feature overlap differs between different correspondence sequences. Unfortunately, this also means that in the standard Simon task the repetition of task features and correspondence sequences are not independent. In order to address this issue, we mapped four stimuli to two responses in the present EEG study. This way, we created a task, which allows for sequences in which the stimulus identity may change without alternating the required response. These sequences may either comprise a change of the stimulus position or not and the contribution of feature integration as well as conflict adaptation processes could thus be observed independently. Our results indicate that the repetition of task features affects performance to a stronger degree than the correspondence sequence and feature integration processes do. Yet, an impact of both could still be observed. The strongest effect of feature repetitions on task performance was observed for task-relevant features, especially for the imperative stimulus identity itself. The EEG results support these findings. The amplitudes of the fronto-central N2 and the parietal P3 decreased with increasing feature overlap from one trial to the next. The posterior lateralization, reflected by the posterior contralateral negativity (PCN), however, appears to reflect mainly changes in the stimulus location and stimulus–response (S–R) correspondence rather than feature repetitions per se.

Increasing Perceptual Salience Diminishes the Motor Interference Effect From Dangerous Objects.

Existing research has indicated that dangerous objects may conflict with an individual’s prepared motor actions and thus slow responses. This phenomenon is called the motor interference effect from dangerous objects. However, its origin remains arguable. The current study aimed to preclude an alternative origin and to investigate whether the efficiency of processing a prepared response toward a dangerous object could benefit from increasing the perceptual salience of the object by painting the object red. The design used a shape categorization task to emphasize the dangerous elements of target objects and manipulated target color (gray versus red), target dangerousness (safe versus dangerous) and prime-target congruency (congruent versus incongruent). The null effect of N2 amplitudes between the dangerous and safe conditions precluded the alternative origin and suggested that the motor interference effect did not originate from response inhibition. Furthermore, the results indicated a modulation effect of the motor interference effect in different colors. The classic motor interference effect was observed in the gray target condition, but it diminished in the red target condition. The underlying cognitive processes were reflected in ERPs. More positive P2 and frontal P3 amplitudes were identified in the red target condition than in the gray target condition, which indicated that deeper feature detection was assigned to and more attentional resources were automatically recruited for the red targets than for the gray targets. Analysis of the parietal P3 amplitudes identified a similar result pattern as the mean RTs. A more positive P3 amplitude was identified in the dangerous condition than in the safe condition when the targets were painted gray. In contrast, the P3 amplitudes were identical between the dangerous condition and the safe condition when the targets were painted red. The results indicated that the increased attentional resources facilitated the evaluation of red target dangerousness and thus accelerated reactions to the red dangerous targets; the reaction speeds to those targets were close to those for the reaction speeds to the red safe targets. Detailed processes that underline these components are discussed.

Temporal dynamics of the flash-induced bouncing effect.

Two identical visual disks moving toward each other on a two‐dimensional (2D) display are more likely to be perceived as “streaming through” than “bouncing off” each other after their coincidence. However, either a brief auditory tone or visual flash presented at the coincident moment of the disks can strikingly increase the incidence of the bouncing percept. Despite the neural substrates underlying the sound‐induced bouncing effect have been widely investigated, little is known about the neural mechanisms underlying the flash‐induced bouncing effect. The present study used event‐related potential recordings to explore the temporal dynamics of the flash‐induced bouncing effect. The results showed that the amplitude of the postcoincidence parietooccipital P2 component (190–230 ms after coincidence) elicited by the visual motion was significantly smaller on bouncing relative to streaming trials only when the flash was presented but not when absent. In addition, the parietal P3 component (330–430 ms) was found to be larger on bouncing than streaming trials when the flash was presented, but the opposite was true when no flash was presented. These electrophysiological findings suggest that the flash‐induced bouncing effect may occur at both perceptual and postperceptual stages of processing.

Fearful faces modulate cognitive control under varying levels of uncertainty: An event-related potential study

Cognitive control can reduce uncertainty, but few studies have investigated temporal dynamics of the flexible allocation of resources under varying levels of uncertainty. We used a revised majority function task with emotional faces and event-related potentials to investigate this process. The task incorporated different ratios of face orientation to quantify uncertainty. Participants performed slower in high uncertainty than in other levels. Under low uncertainty, participants showed greater amplitudes of frontal N200 and late frontal wave to neutral faces than fearful faces. Parietal P300 amplitudes decreased from low uncertainty to high uncertainty, and fearful faces elicited greater P300 amplitudes than neutral faces under all levels of uncertainty. These results suggest that emotion and uncertainty interacted in the frontal cortex during both early and late stages, while no interaction existed in the parietal cortex during the late stage. The interference of fearful faces is lessened by increasing cognitive control under high uncertainty in the frontal cortex, suggesting that humans possess the ability to flexibly allocate mental resources in the temporal domain. Our findings provide evidence to support the fronto-parietal network hypothesis of cognitive control in a novel perspective of uncertainty.

Neural responses of in-group “favoritism” and out-group “discrimination” toward moral behaviors

People hate being deceived. However, what would it be if lies come from in-group members compared with that from out-group members? In the current Electroencephalography (EEG) study, we recruited thirty-six participants to play a modified estimator and advisor game to investigate the mental and neural processes to lies and truth conveyed by in-group and out-group members. At the behavioral level, lies are less morally acceptable, arose less positive emotion, and made participants distribute less money to the advisor in a dictator game. Meanwhile, participants liked the in-group university more than the out-group university and they thought they were more similar to in-group members than to out-group members. However, there were no significant interactions of group type (i.e., in-group and out-group) and message type (i.e., lies and truth) in the aforementioned behavioral assessments. At the neural level, significant interaction effects were found in the parietal N1 and P3 amplitude. More importantly, no significant N1 and P3 amplitude differences between in-group lies and truth were found, while outgroup lies elicited larger P3 amplitude than outgroup truth and out-group truth elicited larger N1 amplitude than outgroup lies. What's more, P3 amplitude differences between lies vs. truth positively correlated with fairness scores only in the in-group condition but not in the out-group condition. Current study showed that the P3 component was sensitive in capturing subtle differences when participants were processing different types of lies and truth that could not be captured by behavioral measurements. Besides, the fairness trait modulated the in-group bias related P3 patterns. The current study provides insight into the neurobiological mechanism underlying the mental process of in-group and out-group lies and truth, and suggests individuals' tendency of general in-group favoritism and out-group discrimination toward moral behaviors.

Parietal P3 and midfrontal theta prospectively predict the development of adolescent alcohol use.

Subclinical adolescent alcohol use is highly prevalent and may have deleterious effects on important psychosocial and brain outcomes. Prior research has focused on identifying endophenotypes of pathological drinking, and the predictors of normative drinking remain understudied. This study investigated the incremental predictive value of two potential psychophysiological endophenotypes, P3 amplitude (an index of decision making) and midfrontal theta power (a correlate of attentional control), for prospectively predicting the expression and initiation of alcohol use emerging in adolescence. A large (N = 594) epidemiological sample was prospectively assessed at ages 11/14/17. Alcohol/substance use was assessed at all ages via a computerized self-report inventory. EEG was recorded at age-14 during a visual oddball task to elicit P3 and theta. Reduced target-related P3 and theta at age-14 prospectively predicted drinking at age-17 independent of one another. Among alcohol-naive individuals at age-14, attenuated P3 and theta increased the odds of new-onset alcohol behaviors 3 years later. Importantly, the endophenotypes provided significant incremental predictive power of future non-clinical alcohol use beyond relevant risk factors (prior alcohol use; tobacco/illicit drug initiation; parental alcohol use disorder). The current report is the first of our knowledge to demonstrate that deviations in parietal P3 and midfrontal theta prospectively predict the emergence of normative/non-pathological drinking. P3 and theta provide modest yet significant explanatory variance beyond prominent self-report and familial risk measures. Findings offer strong evidence supporting the predictive utility of P3 and theta as candidate endophenotypes for adolescent drinking.

Neural Processes of Proactive and Reactive Controls Modulated by Motor-Skill Experiences.

This study investigated the experience of open and closed motor skills on modulating proactive and reactive control processes in task switching. Fifty-four participants who were open-skilled (n = 18) or closed-skilled athletes (n = 18) or non-athletic adults (n = 18) completed a cued task-switching paradigm task. This task tapped into proactive or reactive controls of executive functions under different validity conditions. Electroencephalograms of the participants were captured during the task. In the 100% validity condition, the open-skilled participants showed significantly lower switch cost of response time than the closed-skilled and control participants. Results showed that the open-skilled participants had less positive-going parietal cue-locked P3 in the switch than repeat trials. Participants in the control group showed more positive-going cue-locked P3 in the switch than repeat trials, whereas the closed-skilled participants had no significant differences between the two types of trials. In the 50% validity condition, the open- and closed-skilled participants had less switch cost of response time than the control participants. Participants in the open- and closed-skilled groups showed less positive-going parietal stimulus-locked P3 in the switch than repeat trials, which was not the case for those in the control group. Our findings confirm the dissociation between proactive and reactive controls in relation to their modulations by the different motor-skill experiences. Both proactive and reactive controls of executive functions could be strengthened by exposing individuals to anticipatory or non-anticipatory enriched environments, suggesting proactive and reactive controls involved in motor-skill development seem to be transferable to domain-general executive functions.

Classification of Motor Functions from Electroencephalogram (EEG) Signals Based on an Integrated Method Comprised of Common Spatial Pattern and Wavelet Transform Framework.

In this work, an algorithm for the classification of six motor functions from an electroencephalogram (EEG) signal that combines a common spatial pattern (CSP) filter and a continuous wavelet transform (CWT), is investigated. The EEG data comprise six grasp-and-lift events, which are used to investigate the potential of using EEG as input signals with brain computer interface devices for controlling prosthetic devices for upper limb movement. Selected EEG channels are the ones located over the motor cortex, C3, Cz and C4, as well as at the parietal region, P3, Pz and P4. In general, the proposed algorithm includes three main stages, band pass filtering, CSP filtering, and wavelet transform and training on GoogLeNet for feature extraction, feature learning and classification. The band pass filtering is performed to select the EEG signal in the band of 7 Hz to 30 Hz while eliminating artifacts related to eye blink, heartbeat and muscle movement. The CSP filtering is applied on two-class EEG signals that will result in maximizing the power difference between the two-class dataset. Since CSP is mathematically developed for two-class events, the extension to the multiclass paradigm is achieved by using the approach of one class versus all other classes. Subsequently, continuous wavelet transform is used to convert the band pass and CSP filtered signals from selected electrodes to scalograms which are then converted to images in grayscale format. The three scalograms from the motor cortex regions and the parietal region are then combined to form two sets of RGB images. Next, these RGB images become the input to GoogLeNet for classification of the motor EEG signals. The performance of the proposed classification algorithm is evaluated in terms of precision, sensitivity, specificity, accuracy with average values of 94.8%, 93.5%, 94.7%, 94.1%, respectively, and average area under the receiver operating characteristic (ROC) curve equal to 0.985. These results indicate a good performance of the proposed algorithm in classifying grasp-and-lift events from EEG signals.

Recording mobile EEG in an outdoor environment reveals cognitive-motor interference dependent on movement complexity

Oftentimes we find ourselves in situations in which we need to perform concurrent motor and cognitive tasks like simple locomotion while being cognitively involved. In the present study, we investigated in how far cognitive and motor functioning interfere in an outdoor environment. Our participants performed an auditory oddball task while concurrently completing various motor tasks on the outside premises of our institute. Beside behavioural responses and subjective workload ratings, we also analysed electrophysiological data recorded with a 30-channel mobile EEG montage. We observed an increase of subjective workload and decrease of performance with increasing movement complexity. Accordingly, we also found a decrease in the parietal P3 amplitude as well as in frontal midline Theta power with higher motor load. These results indicate that an increased movement complexity imposes a higher workload to the cognitive system, which, in turn, effectively reduces the availability of cognitive resources for the cognitive task. Overall this experiment demonstrates the feasibility of transferring classical paradigms of cognitive research to real-world settings. The findings support the notion of shared resources for motor and cognitive functions by demonstrating distinct modulations of correlates of cognitive processes across different motor tasks.

Effects of physical exercise on negative emotional susceptibility in young adult females: An event-related potential study

The present study investigated whether habitual physical exercise can regulate susceptibility to negative emotions in young adult female participants. Female participants with and without long-term physical exercise habits were recruited and assigned to exercise and non-exercise groups, respectively. All participants performed a standard/deviant distinction task in which the emotional valence of the deviants could be highly negative (HN), moderately negative (MN), or neutral. Event-related potentials (ERPs) elicited by deviants were recorded and compared between the two groups. Regardless of the emotional valence of the deviants, the exercise group exhibited shorter reaction times (RTs) and greater parietal P3 responses to all deviants, compared to the non-exercise group, consistent with a superiority in detecting and responding to deviants. Importantly, whereas the non-exercise group showed greater frontal-central N2 responses to MN deviant stimuli than to neutral deviant stimuli, such a difference was not observed in the exercise group, indicating that the participants who exercised regularly had decreased attentional capture and allocation to MN deviants, and thus an apparent decreased negative emotional susceptibility selectively to moderately negative emotional stimuli. These results may indicate an effect of physical exercise on the processing of negative emotional information and support the promotion of physical exercise in the maintenance of mental health in females.

On ignoring words-exploring the neural signature of inhibition of affective words using ERPs.

In the present study event-related potentials were used to shed further light on the neural signatures of active inhibition of the (affective) content of written words. Intentional inhibition was implemented by simply asking participants (N = 32) to ignore single words that served as primes in an affective priming (AP) task. In AP, evaluations about a priori neutral targets typically tend to shift towards the valence of preceding primes, denoting an AP effect (APE). To create a plausible cover-context emphasizing the usefulness of word inhibition, participants were asked to avoid this shift, that is, to make unbiased target evaluations. Ignoring the prime words was suggested as the most efficient strategy to achieve this aim. Effective inhibition of the words' (affective) content, as suggested by a significant APE present for words processed without any further instruction, but not for ignored ones, affected multiple stages of processing. On the neuronal level, word inhibition was characterized by reduced early perceptual (left-lateralized word-specific N170), later attentional (parietal P300), and affective-semantic processing (reduced posterior semantic asymmetry). Furthermore, an additional recruitment of top-down inhibitory control processes, which was mirrored in increased amplitudes of medial-frontal negativity, showed to be critically involved in intentional word inhibition.

Group-Level Neural Responses to Service-to-Service Brand Extension.

Brand extension is a marketing strategy leveraging well-established brand to promote new offerings provided as goods or service. The previous neurophysiological studies on goods-to-goods brand extension have proposed that categorization and semantic memory processes are involved in brand extension evaluation. However, it is unknown whether these same processes also underlie service-to-service brand extension. The present study, therefore, aims to investigate neural processes in consumers underlying their judgment of service-to-service brand extension. Specifically, we investigated human electroencephalographic responses to extended services that were commonly considered to fit well or badly with parent brand among consumers. For this purpose, we proposed a new stimulus grouping method to find commonly acceptable or unacceptable service extensions. In the experiment, participants reported the acceptability of 56 brand extension pairs, consisting of parent brand name (S1) and extended service name (S2). From individual acceptability responses, we assigned each pair to one of the three fit levels: high- (i.e., highly acceptable), low-, and mid-fit. Next, we selected stimuli that received high/low-fit evaluations from a majority of participants (i.e., >85%) and assigned them to a high/low population-fit group. A comparison of event-related potentials (ERPs) between population-fit groups through a paired t-test showed significant differences in the fronto-central N2 and fronto-parietal P300 amplitudes. We further evaluated inter-subject variability of these ERP components by a decoding analysis that classified N2 and/or P300 amplitudes into a high, or low population-fit class using a support vector machine. Leave-one-subject-out validation revealed classification accuracy of 60.35% with N2 amplitudes, 78.95% with P300, and 73.68% with both, indicating a relatively high inter-subject variability of N2 but low for P300. This validation showed that fronto-parietal P300 reflected neural processes more consistent across subjects in service-to-service brand extension. We further observed that the left frontal P300 amplitude was increased as fit-level increased across stimuli, indicating a semantic retrieval process to evaluate a semantic link between S1 and S2. Parietal P300 showed a higher amplitude in the high population-fit group, reflecting a similarity-based categorization process. In sum, our results suggest that service-to-service brand extension evaluation may share similar neural processes with goods-to-goods brand extension.

A meta-analysis of the P3 amplitude in tasks requiring deception in legal and social contexts

In deception tasks the parietal P3 amplitude of the event-related potential indicates either recognition of salient stimuli (larger P3 following salient information) or mental effort (smaller P3 following demanding information). This meta-analysis (k = 77) investigated population effect sizes (δ) for conceptual and methodological a-priori moderators (study design, pre-task scenario, context of deception tasks, and P3 quantification). Within-subject designs show evidence of the underlying cognitive processes, between-subject designs allow for comparisons of cognitive processes in culprits vs. innocents. Committed vs. imagined mock crime scenarios yield larger δ. Deception tasks with a legal context result in almost twice as large δ than deception tasks with social-evaluative and social-biographical contexts. Peak-to-peak P3 quantification resulted in larger δ than other quantifications. Counter-measure techniques in 3-stimulus protocols reduce the discriminability of concealed vs. truthful P3 amplitudes. Depending on stimulus knowledge, deception tasks provide evidence for the salience hypothesis and the mental effort hypothesis, respectively.