Event-related potential N270 is elicited by mental conflict processing in human brain

How negative emotions influence arithmetic problem-solving processes: An ERP study

We investigated the effects of negative emotions on arithmetic performance using ERPs. Participants were asked to verify complex multiplication problems that were either true (e.g., 3 × 23 = 69) or false (e.g., 5 × 98 = 485). Half the problems were five problems (e.g., 5 × 94 = 470) and half were non-five problems (e.g., 8 × 63 = 504). False five problems violated arithmetic rules (i.e., the five rule, e.g., 5 × 17 = 87, the parity-rule, e.g., 86 × 5 = 435, both the five- and parity-rules, e.g., 5 × 42 = 411) or no arithmetic rules (e.g., 13 × 5 = 45). Problems were displayed superimposed on emotionally neutral or negative pictures. Behavioral results showed that negative emotions (a) did not affect participants' performance on true five and non-five problems, (b) influenced arithmetic performance on false five problems, and (c) impaired performance on problems that violated both the five- and parity-rules but improved performance on false five problems violating no arithmetic rules. Electrophysiological data revealed that negative emotions led to (a) earlier P1 peak when participants verified true, non-five problems, (b) lower P300 and P600 amplitudes in central brain regions when participants verified false five problems that violated no-rule, (c) earlier N2 peak latencies in central brain regions and larger LPC amplitudes in right parietal regions while participants verified parity-rule violation problems, and (d) earlier N2 peak latencies in central brain regions and later N2 peak latencies in the right prefrontal brain regions while participants verified false, five problems violating both the five- and parity-rules. These findings demonstrate that negative emotions significantly alter key stages of arithmetic problem-solving by modulating neural activity related to encoding, detection of rule violations, and strategic execution, as evidenced by changes in the amplitude and latency of ERP components such as P1, N2, P300, P600, and LPC.

Promotion framing effects on the purchase of hedonic-utilitarian bundles: ERPs evidence of the moderating role of income source

Prior studies suggest that people are susceptible to the promotion framing effect. Yet it's still unknown if income source moderates the effect of promotion frame on consumer decision-making and the underlying neural responses. The current study applied the event-related potentials (ERPs) approach to exploring the moderating role of income source (hard-earned income and windfall income) on the promotion framing effect in a cross-category bundling context. Two promotion frames were created with identical total prices for a cross-category bundle that included both hedonic and utilitarian products. The behavioral results showed that income source moderated the effect of promotion frame on neural responses and purchase decision-making. When participants obtained a hard-earned income, they showed an attenuated N2, an enlarged LPP amplitude, and a higher purchase rate in the hedonic (vs. utilitarian) freebie condition; but when they obtained a windfall income, the effect of promotion frame disappeared. Overall, the conclusions have important ramifications for both theory and practice.

The brain responses to the gating opening mechanism on perceptual and conceptual mismatches in the 1-back matching task

OBJECTIVE

Although working memory performance is predicted by the gating mechanism, which is part of attentional control, the attentional control effect on domain-specific matching processes in the 1-back task, is lack of neural evidence.

METHOD

This study adopted event-related potential (ERP) technique, and employed both perceptual and conceptual matching conditions in a digital 1-back task, requiring to judge whether the current number was perceptually or quantitatively identical to the prior one. Three types of number pairs were adopted: shape/value match (S + V +, e.g., '3 3' or ' '), shape mismatch/value match (S - V + , e.g., '3 ' or ' 5') and shape/value mismatch (S - V - , e.g., '3 5' or ' ').

MAIN RESULTS

The ERP results showed that both S - V + and S - V - elicited similar larger P2 amplitudes and longer N2 and P3 latencies than S + V + in both conditions, reflecting the gate opening for perceptual input. Moreover, a task-relevance effect on P3 amplitudes was observed, with a deflection for S - V - in the conceptual matching condition and for S - V + and S - V - in the perceptual matching condition, suggesting that the gating opening mechanism enabled the retrieval of relevant information.

CONCLUSION

Hence, the matching effect on P3 supported the gating opening mechanism on the matching subprocess underlying the N-back task.

Distinct Patterns of Automatic and Controlled Incongruent Information Processing in the Human Brain

It is a fundamental ability to discriminate incongruent information in daily activity. However, the underlying neural dynamics are still unclear. Using stereoelectroencephalography (SEEG), in this study, we investigated the fine-grained and different states of incongruent information processing in patients with refractory epilepsy who underwent intracranial electrode implantation. All patients performed a delayed match-to-sample paradigm in the sequential pairs of visual stimuli (S1 followed by S2). Participants were asked to discriminate whether the relevant feature of S2 was identical to S1 while ignoring the irrelevant feature. The spatiotemporal cortical responses evoked by different conditions were calculated and compared, respectively, in the context of brain intrinsic functional networks. In total, we obtained SEEG recordings from 241 contacts in gray matter. In the processing of irrelevant incongruent information, the activated brain areas included the superior parietal lobule, supramarginal gyrus, angular gyrus, inferior temporal gyrus, and fusiform gyrus. By comparing the relevant incongruent condition with the congruent condition, the activated brain areas included the middle frontal gyrus, superior temporal gyrus, middle temporal gyrus, posterior superior temporal sulcus, and posterior cingulate cortex. We demonstrated the dynamics of incongruent information processing with high spatiotemporal resolution and suggested that the process of automatic detection of irrelevant incongruent information requires the involvement of local regions and relatively few networks. Meanwhile, controlled discrimination of relevant incongruent information requires the participation of extensive regions and a wide range of nodes in the network. Furthermore, both the frontoparietal control network and default mode network were engaged in the incongruent information processing.

Distinct multisensory perceptual processes guide enhanced auditory recognition memory in older cochlear implant users

•

Congruent audio-visual encoding enhances later auditory processing in the elderly.

•

CI users benefit from additional congruent visual information, similar to controls.

•

CI users show distinct neurophysiological processes, compared to controls.

•

CI users show an earlier modulation of event-related topographies, compared to controls.

In naturalistic situations, sounds are often perceived in conjunction with matching visual impressions. For example, we see and hear the neighbor’s dog barking in the garden. Still, there is a good chance that we recognize the neighbor’s dog even when we only hear it barking, but do not see it behind the fence. Previous studies with normal-hearing (NH) listeners have shown that the audio-visual presentation of a perceptual object (like an animal) increases the probability to recognize this object later on, even if the repeated presentation of this object occurs in a purely auditory condition. In patients with a cochlear implant (CI), however, the electrical hearing of sounds is impoverished, and the ability to recognize perceptual objects in auditory conditions is significantly limited. It is currently not well understood whether CI users – as NH listeners – show a multisensory facilitation for auditory recognition. The present study used event-related potentials (ERPs) and a continuous recognition paradigm with auditory and audio-visual stimuli to test the prediction that CI users show a benefit from audio-visual perception. Indeed, the congruent audio-visual context resulted in an improved recognition ability of objects in an auditory-only condition, both in the NH listeners and the CI users. The ERPs revealed a group-specific pattern of voltage topographies and correlations between these ERP maps and the auditory recognition ability, indicating a different processing of congruent audio-visual stimuli in CI users when compared to NH listeners. Taken together, our results point to distinct cortical processing of naturalistic audio-visual objects in CI users and NH listeners, which however allows both groups to improve the recognition ability of these objects in a purely auditory context. Our findings are of relevance for future clinical research since audio-visual perception might also improve the auditory rehabilitation after cochlear implantation.

Incongruity in fraction verification elicits N270 and P300 ERP effects

Understanding how the numerical magnitudes of fractions are accessed is a topic of major interest in numerical cognition and mathematics education. Only a few studies have investigated fraction processing using EEG methods. In the present study, 24 adult participants completed a fraction magnitude verification task while EEGs were recorded. Similar to other arithmetic verification tasks, behavioral results show increased response times to validate mismatching magnitudes compared to matching ones. ERP results show an early frontal N270 component to mismatching trials and a late parietal P300 component during matching trials. These ERP results highlight that participants treat matching fractions as targets and suggest that additional cognitive resources are needed to process mismatching targets. These results provide evidence that fractions processing shares a similar neurocognitive process as those observed during the processing of arithmetic operations and open the door to further explore fraction processing using ERP methods.

Does mobile payment change consumers' perception during payment process? -An ERP study

Innovative payment methods have been getting worldwide attention. Exploring the mechanisms behind consumers' purchase behaviors modulated by different payment methods was critical but challenging. In this paper, we proposed a 2 (payment methods: cash payment vs mobile payment) × 2 (price levels of products: high vs low) Event-Related Potentials (ERPs) experiment to study the difference of cash payment and mobile payment on consumers' purchase intention of products in different price level from a neuroscience perspective. Greater P200 amplitude was found in mobile payment condition, which meant that mobile payment captured more early attention resources than cash. Larger N270 amplitude was found in cash payment condition as the participants had to spend more cognitive resources and struggled more when using cash. Moreover, lower N270 amplitude was found in high-price product condition, which indicated that when there were limited cognitive resources, the affective process played a dominating role. Specifically, buying the high-price products with mobile payment, the consumers would experience the pleasure of consumption more rather than the pain of paying. The study offers insights on the cognitive process of consumers when they pay with different methods.

When old information is intermixed with new elements: An event-related potential study

Previous research has focused on the event-related potential of the old/new effect, but the mechanism for cognitive conflict and subsequent integration processing both induced by intermixed (old and new) stimuli have not been widely researched. This paper describes the effect of familiar stimuli mixed with new information and presented as intermixed stimuli. Three conditions were set within a study-test paradigm incorporating old, new, and intermixed conditions. The intermixed condition resulted in the lowest accuracy, thereby implying the greatest old/new effect. Moreover, compared with the old condition, the intermixed condition elicited a greater N270 as well as a stronger N400, while the new condition only induced a stronger N270. These results elucidate that when new information is intermixed with old information, the old/new effect is more pronounced, indicating that intermixed stimuli are possibly more difficult to integrate than old and new stimuli.

Coordinating Initial and Final Action Goals in Planning Grasp-to-Rotate Movements: An ERP Study

Action goals have often been investigated in previous studies within a single action. However, most of the manual actions (such as prehension) are not restricted to a single action towards the object but can involve multiple follow-up actions to achieve a further purpose. The coordination of the initial (grip posture) and final (task purpose) action goals within such complex actions is still not fully understood. In the present experiment, the neural mechanisms underlying the goal coordination were investigated with the help of event-related potentials (ERP). With the "first cue - second cue - imperative signal" design, the action goals were presented separately in different sequences (either "final-initial" or "initial-final"), and participants were instructed to plan and execute a grasp-to-rotate movement with either free-choice or specified grasping. Results revealed that shorter reaction times were needed for the final-initial than for the initial-final trials only when the movement requires a free-choice grasping. At the moment when the goal information was incomplete (at the first cue), final goals evoked a larger anterior P2 than initial goals, whereas initial goals elicited a larger anterior N2 and a more robust frontal negativity (400--550 ms) than final goals. When the goal information was complete (at the second cue), we only found a larger P2 for final goals than for initial goals in free-choice grasping. Moreover, a larger N2 was also found for the specified than for the free-choice grasping in initial-final trials. These neurophysiological results indicate that final goals are more critical than initial grip postures in planning prehensile movements. The initial and final action goals seem to be preferably coordinated in a hierarchical manner, that is, the final task purpose is processed with precedence, whereas the initial grip posture is selected depending on the final task purpose.

The neural differences of arithmetic verification performance depend on math skill: Evidence from event-related potential

AIM

Math skill is a basic need for an individual, as a career prospect. However, little is known about early brain processes of arithmetic between individuals with different math skill. Therefore, we questioned the modulation of the amplitude of an early negative component by math skill level in an arithmetic verification paradigm using event-related potential (ERP).

METHODS

Thirty-six right-handed participants were assigned in two groups of high- and low-performing students. Their electroencephalogram was recorded while they completed an arithmetic verification task. Simple arithmetic operands were made by random digits from 1 to 9. Addition and subtraction operations were equally used in correct and incorrect responses. The accuracy scores, reaction times, and peak amplitude of the negativity in 200-400 ms time window were analyzed.

RESULTS

The high-performing group showed significantly higher response speeds, and they were more accurate than the low-performing group. The group × region interaction effect was significant. The high-performing group showed a significantly greater negativity, particularly in parietal region, while the low-performing group showed a significantly deeper negativity in frontal and prefrontal region. In the low-performing group, there were significant peak amplitude differences between the anterior and posterior areas. However, such differences were not detected in the high-performing group.

CONCLUSION

Students with different mathematical performance showed distinct patterns in early processing of arithmetic verification, as reflected by differences in negativity at 200-400 ms at anterior and posterior. This suggests that ERPs could be used to differentiate math mastery at neural level which is beneficial in educational and clinical contexts.

Face-like configurations modulate electrophysiological mismatch responses

The human face is one of the most salient stimuli in the environment. It has been suggested that even basic face-like configurations (three dots composing a downward pointing triangle) may convey salience. Interestingly, stimulus salience can be signaled by mismatch detection phenomena, characterized by greater amplitudes of event-related potentials (ERPs) in response to relevant novel stimulation as compared to non-relevant repeated events. Here, we investigate whether basic face-like stimuli are salient enough to modulate mismatch detection phenomena. ERPs are elicited by a pair of sequentially presented visual stimuli (S1-S2), delivered at a constant 1-s interval, representing either a face-like stimulus (Upright configuration) or three neutral configurations (Inverted, Leftwards, and Rightwards configurations), that are obtained by rotating the Upright configuration along the three different axes. In pairs including a canonical face-like stimulus, we observe a more effective mismatch detection mechanism, with significantly larger N270 and P300 components when S2 is different from S1 as compared to when S2 is identical to S1. This ERP modulation, not significant in pairs excluding face-like stimuli, reveals that mismatch detection phenomena are significantly affected by basic face-like configurations. Even though further experiments are needed to ascertain whether this effect is specifically elicited by face-like configuration rather than by particular orientation changes, our findings suggest that face essential, structural attributes are salient enough to affect change detection processes.

Task relevance effect on number/shape conflict detection in the number-matching task: An ERP study

It is debatable whether the task relevance effect on a conflict occurs in the detection or in the inhibition underlying sequential matching. To explore this issue, three types of number pairs, identical (e.g., 12, 12), conserved (e.g., 12, ), and non-conserved (e.g., 12, 15) pairs, were displayed to be judged as perceptually (identical shape condition) or quantitatively (identical value condition) the same. Both error rates and RTs for the three types of number pairs showed different patterns to detect perceptual mismatch in the identical shape condition and number inequivalence in the identical value conditions. The event-related potential (ERP) results showed that increased N200 and N400 as well as decreased P300 were triggered by the conserved and non-conserved pairs in contrast to identical pairs in the identical shape condition and by the non-conserved pairs relative to the conserved and identical pairs in the identical value condition. These results showed that task-relevant mismatches were attended to and detected in both conditions. Therefore, for the task-relevance effect on a conflict, attention is selectively directed to task-relevant features rather than inhibiting task-irrelevant conflict.

A Facilitatory Effect of Perceptual Incongruity on Target-Source Matching in Pictorial Metaphors of Chinese Advertising: EEG Evidence

Using evoked response potentials, we investigated the implicit detection of incongruity during target-source matching in pictorial metaphors of Chinese advertising. Participants saw an image of a product (the target in a visual metaphorical relationship), and then made a same-different judgment in response to a second image (the source in a visual metaphorical relationship) which was (in)congruous to the first image in terms of shape and/or function. We collected behavioral (button-press reaction time and accuracy), and neural (N270, delta and theta band activity) measures. The time-frequency analysis showed faster processing of incongruous visual information. Moreover, shape and conceptual incongruity were associated with increased N270 amplitude as well as delta (1-3 Hz) and theta (4-8 Hz) band power. Noticeably, compared with conceptual incongruity, shape incongruity evoked a larger N270 amplitude and stronger delta and theta band oscillation. In addition, the average topographical analysis revealed a frontal and central distribution of the power activity. The analysis of attitudes towards the advertising metaphor pictures also proved the supportive role played by incongruity. In conclusion, incongruity facilitates target-source matching in pictorial metaphors of Chinese advertising. The findings obtained from the study are important to metaphor designs of advertising pictures.

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.

Electrophysiological markers of poor versus superior math abilities in healthy individuals

Interindividual differences in the numerical ability of healthy adults have been previously demonstrated, mainly with tasks involving mental number line or size representation. However, electrophysiological correlates of superior versus poor arithmetic ability (in the healthy population) have been scarcely investigated. We correlated electric potentials with math performance in 13 skilled and 13 poor calculators selected from a sample of 41 graduate students on the basis of their poor or superior math abilities assessed through a timed test. EEG was recorded from 128 channels while participants solved 352 arithmetical operations (additions, subtractions, multiplications, divisions) and decided whether the provided solution was correct or incorrect. Overall skilled individuals correctly solved a higher number of operations than poor calculators and had faster response times. Consistently, the latency of fronto-central P300 component of event-related potentials (ERPs) peaked earlier in the skilled than poor group. The P300 was larger in amplitude to correct than incorrect solutions, but just in the skilled group, with a tendency found in poor calculators. Spearman's ρ correlation coefficient analyses showed that the larger P300 response was to correct arithmetic solutions, the better the performance; conversely, the larger the P300 amplitude was to incorrect solutions, the worse the performance. The results suggest that poor calculators had a less clear representation of arithmetic solutions and difficulty in quickly accessing it. This study provides a standard method for directly investigating math abilities throughout ERP recordings that could be useful for assessing acalculia/dyscalculia in the clinical population (children, elderly, brain-damaged patients).

Automatic Conflict Monitoring by Event-Related Potentials Could be used to Estimate Visual Acuity Levels

Numerous studies have explored the physical attribute features or face perceptions in conflict processing, while complicate gradient conflicts were rarely discussed. The aim of the study was to discuss the relationship between the event-related potential (ERP) component features and different visual acuity levels by using the modified S1-S2 task under non-attention status. Three visual acuity levels were applied, each with four orientations of "E" optotype stimuli randomly presented in the center of the visual field while participants were required to concentrate on listening to stories. The results showed that the amplitudes of P1 and P3 as well as difference P3 were larger in supra-threshold condition. In threshold condition, larger amplitudes for both N2 and difference N2 exhibited in frontal and central areas. In sub-threshold condition, there was no endogenous component elicited by mismatch stimuli except smaller anterior N1. Meanwhile, the specific distributions of N1 and N2 were presented and compared with previous face processing. The findings showed that visual conflict processing took place not only at an early stage but also at the late period, which might be as the consequences of interaction between conflict strength and involuntary attention. We concluded that automatic conflict detecting of visual icons by the serial ERP components could distinguish different visual acuity levels. The involvement of endogenous components could reveal the specific mechanism of more precise and fine conflict identification of complex physical attributes under non-attention status, furthermore could be used as valid markers to estimate the magnitude of visual acuity objectively.

The neural correlates of vertical disparity gradient and cue conflict in Panum's limiting case

Although Panum's limiting case has been extensively researched, only recently has it been discovered that in addition to horizontal disparity, the final perception of depth is influenced by (i) the vertical disparity gradient and (ii) the degree of cue conflict between 2D and 3D shapes. The present study examines the neural correlates of the two factors, using EEG while observers viewed several versions of stereoscopic stimuli, which depicted Panum's limiting case. In these patterns the vertical disparity gradient was varied from 0.1 to 0.6, while the degree of cue conflict was manipulated from low to high. The ERP data showed that the amplitude of the N170 component (exogenous) was modulated by the vertical disparity gradient and cue conflict. In contrast, the N270 component (endogenous) was modulated by cue conflict only. Such findings demonstrate that both factors affect the perception of depth in Panum's limiting case, but at different stages: the vertical disparity gradient at an early stage of processing (N170) and cue conflict at two stages (N170 and N270). Hence, vertical disparity gradient is related to low-level visual stimulus parameters and can modulate exogenous component, while cue conflict is related to both exogenous and endogenous components.

Interstimulus Interval Effect on Event-Related Potential N270 in a Color Matching Task

Event-related brain potentials were recorded in a matching task, in which subjects were asked to discriminate if the color of the second stimulus (S2) was the same as the first stimulus (S1). The interstimulus interval between the two stimuli of a pair was of three levels (150 ms, 500 ms and 1000 ms). A negative component about 270 ms after the presentation of S2 was elicited when the color of the two stimuli was not identical for the interstimulus interval of 500 ms and 1000 ms, but not for the interval of 150 ms. This may suggest that N270 represented the response of the brain to conflicting information between different cortical levels.

Puzzle task ERP response: time-frequency and source localization analysis

Perceptual decision making depends on the choices available for the presented task. Most event-related potential (ERP) experiments are designed with two options, such as YES or NO. In some cases, however, subjects may become confused about the presented task in such a way that they cannot provide a behavioral response. This study aims to put subjects into such a puzzled state in order to address the following questions: How does the brain respond during puzzling moments? And what is the brain’s response to a non-answerable task? To address these questions, ERP were acquired from the brain during a scintillation grid illusion task. The subjects were required to count the number of illusory dots, a task that was impossible to perform. The results showed the presence of N130 over the parietal area during the puzzling task. Coherency among the brain hemispheres was enhanced with the complexity of the task. The neural generators’ source localizations were projected to a multimodal complex covering the left postcentral gyrus, supramarginal gyrus, and angular gyrus. This study concludes that the brain component N130 is strongly related to perception in a puzzling task network but not the visual processing network.

Neural Mechanisms of Selective Attention in Children with Amblyopia

Previous studies have indicated that amblyopia might affect children's attention. We recruited amblyopic children and normal children aged 9-11 years as study subjects and compared selective attention between the two groups of children. Chinese characters denoting colors were used in the Stroop task, and the event-related potential (ERP) was analyzed. The results show that the accuracy of both groups in the congruent condition was higher than the incongruent condition, and the reaction time (RT) of amblyopic children was longer. The latency of the occipital P1 in the incongruent condition was shorter than the neutral condition for both groups; the peak of the occipital P1 elicited by the incongruent stimuli in amblyopic children was higher. In both groups, the N1 peak was higher in the occipital region than frontal and central regions. The N1 latency of normal children was shorter in the congruent and neutral conditions and longer in the incongruent condition; the N1 peak of normal children was higher. The N270 latencies of normal children in the congruent and neutral conditions were shorter; the N270 peak was higher in parietal and occipital regions than frontal and central regions for both groups. The N450 latency of normal children was shorter; in both groups, the N450 average amplitude was significantly higher in the parietal region than central and frontal regions. The accuracy was the same for both groups, but the response of amblyopic children was significantly slower. The two groups showed differences in both stages of the Stroop task. Normal children showed advantages in processing speed on both stimulus and response conflict stages.Brain regions activated during the Stroop task were consistent between groups, in line with their age characteristics.

Event-related potential parameters of category and property violations during semantic category-based induction

Previous studies have failed to clarify the event-related potentials (ERPs) that occur in response to categorization and property inferences during category-based induction. The present study examined ERP differences among acceptable-induction conclusions, unrelated-category conclusions, and unrelated-property conclusions to dissociate categorization and property-inference processing during category-based induction. The results showed that: (a) conclusions with categories that were unrelated to the premise evoked greater frontal N2 amplitudes, smaller P3b amplitudes, and greater N400 amplitudes, compared to conclusions with categories that were logically related to the premise; and (b) conclusions with unrelated properties evoked larger late positive components (LPCs) during the 700-800ms time interval compared to conclusions with related properties. These results suggest that the N2-P3b-N400 effects reflect categorization violations, while the LPCs are related to property violations during category-based induction, therefore, the ERP responses to category-related and property-related processes are dissociated respectively during category-based induction.

Conceptual Integration of Arithmetic Operations With Real-World Knowledge: Evidence From Event-Related Potentials

Research on language processing has shown that the disruption of conceptual integration gives rise to specific patterns of event-related brain potentials (ERPs)-N400 and P600 effects. Here, we report similar ERP effects when adults performed cross-domain conceptual integration of analogous semantic and mathematical relations. In a problem-solving task, when participants generated labeled answers to semantically aligned and misaligned arithmetic problems (e.g., 6 roses + 2 tulips = ? vs. 6 roses + 2 vases = ?), the second object label in misaligned problems yielded an N400 effect for addition (but not division) problems. In a verification task, when participants judged arithmetically correct but semantically misaligned problem sentences to be "unacceptable," the second object label in misaligned sentences elicited a P600 effect. Thus, depending on task constraints, misaligned problems can show either of two ERP signatures of conceptual disruption. These results show that well-educated adults can integrate mathematical and semantic relations on the rapid timescale of within-domain ERP effects by a process akin to analogical mapping.

Dissociation between arithmetic relatedness and distance effects is modulated by task properties: an ERP study comparing explicit vs. implicit arithmetic processing

•

ERPs were recorded while performing number matching and arithmetic verification tasks.

•

Access to the arithmetic facts lexicon is modulated by task properties.

•

Arithmetic relatedness and distance effects are sensitive to task properties.

•

Matching tasks involve semantic processes.

•

Verification tasks involve semantic and detection of mismatch processes.

Event-related potential (ERP) studies have detected several characteristic consecutive amplitude modulations in both implicit and explicit mental arithmetic tasks. Implicit tasks typically focused on the arithmetic relatedness effect (in which performance is affected by semantic associations between numbers) while explicit tasks focused on the distance effect (in which performance is affected by the numerical difference of to-be-compared numbers). Both task types elicit morphologically similar ERP waves which were explained in functionally similar terms. However, to date, the relationship between these tasks has not been investigated explicitly and systematically. In order to fill this gap, here we examined whether ERP effects and their underlying cognitive processes in implicit and explicit mental arithmetic tasks differ from each other. The same group of participants performed both an implicit number-matching task (in which arithmetic knowledge is task-irrelevant) and an explicit arithmetic-verification task (in which arithmetic knowledge is task-relevant). 129-channel ERP data differed substantially between tasks. In the number-matching task, the arithmetic relatedness effect appeared as a negativity over left-frontal electrodes whereas the distance effect was more prominent over right centro-parietal electrodes. In the verification task, all probe types elicited similar N2b waves over right fronto-central electrodes and typical centro-parietal N400 effects over central electrodes. The distance effect appeared as an early-rising, long-lasting left parietal negativity. We suggest that ERP effects in the implicit task reflect access to semantic memory networks and to magnitude discrimination, respectively. In contrast, effects of expectation violation are more prominent in explicit tasks and may mask more delicate cognitive processes.

An ERP study of simple addition: the semantics and syntax of arithmetic operation sign

The aim of the current study was to examine brain activity of adult regular calculators while processing addition sums with different types of answers. The task was a verification task, the incorrect answers were divided into two types: one was comprised of three numbers that do not belong to any additive triplet (such as 2, 4, 7) and it was always near the correct result (± 1); the other was a number which is related to the two numbers which appear in the stimulus but belongs to an incorrect competing triplet of numbers and it was always in a greater distance from the correct answer. Differences were found between the different types of answers in the behavioral reaction time with longest reaction time for the competing triplet and the shortest reaction time for the correct answer. In addition, differences in the latency and amplitude of the N170, N270, N400 and P600 components were found among the different types of answers. It can be concluded from these results that the effect of the interference of the competing triplets is greater than the split effect (distance effect), and that there is a different time zone for coding the numbers and coding of other more general syntactic-semantic arithmetic signs.

Phonological coding during reading

The exact role that phonological coding (the recoding of written, orthographic information into a sound based code) plays during silent reading has been extensively studied for more than a century. Despite the large body of research surrounding the topic, varying theories as to the time course and function of this recoding still exist. The present review synthesizes this body of research, addressing the topics of time course and function in tandem. The varying theories surrounding the function of phonological coding (e.g., that phonological codes aid lexical access, that phonological codes aid comprehension and bolster short-term memory, or that phonological codes are largely epiphenomenal in skilled readers) are first outlined, and the time courses that each maps onto (e.g., that phonological codes come online early [prelexical] or that phonological codes come online late [postlexical]) are discussed. Next the research relevant to each of these proposed functions is reviewed, discussing the varying methodologies that have been used to investigate phonological coding (e.g., response time methods, reading while eye-tracking or recording EEG and MEG, concurrent articulation) and highlighting the advantages and limitations of each with respect to the study of phonological coding. In response to the view that phonological coding is largely epiphenomenal in skilled readers, research on the use of phonological codes in prelingually, profoundly deaf readers is reviewed. Finally, implications for current models of word identification (activation-verification model, Van Orden, 1987; dual-route model, e.g., M. Coltheart, Rastle, Perry, Langdon, & Ziegler, 2001; parallel distributed processing model, Seidenberg & McClelland, 1989) are discussed.

Neural processes underlying the"same"-"different" judgment of two simultaneously presented objects--an EEG study

The present study investigated the neural processes underlying “same” and -“different” judgments for two simultaneously presented objects, that varied on one or both, of two dimensions: color and shape. Participants judged whether or not the two objects were “same” or “different” on either the color dimension (color task) or the shape dimension (shape task). The unattended irrelevant dimension of the objects was either congruent (same-same; different-different) or incongruent (same-different). ERP data showed a main effect of color congruency in the time window 190–260 ms post-stimulus presentation and a main effect of shape congruency in the time window 220–280 ms post-stimulus presentation in both color and shape tasks. The interaction between color and shape congruency in the ERP data occurred in a later time window than the two main effects, indicating that mismatches in task-relevant and task-irrelevant dimensions were processed automatically and independently before a response was selected. The fact that the interference of the task-irrelevant dimension occurred after mismatch detection, supports a confluence model of processing.

The N3 is sensitive to odd-even congruency information in arithmetic fact retrieval

This study investigated the behavioral and electrophysiological effects elicited by adults' simple addition verification when false answers agree or disagree with the odd-even status of the correct sum (parity congruency vs. parity incongruency), while they are near or far from correct (small vs. large splits). Event-related brain potentials were recorded from 18 students using a first-answer-then-problem paradigm. The results showed that odd-even congruency had a significant effect on the N3 latency with a small, but not a large split. Specifically, odd-even congruent answers with a small split elicited an N3 with a longer latency. Analyses of RT similarly indicated a bigger parity-congruency effect with small-split answers compared with large-split answers. This pattern parallels the corresponding effects on N3 and confirms that the N3 is sensitive to odd-even information in arithmetic fact retrieval and that there are clear links between the event-related brain potential pattern and behavioral effects.

The extended fronto-striatal model of obsessive compulsive disorder: convergence from event-related potentials, neuropsychology and neuroimaging

In this work, we explored convergent evidence supporting the fronto-striatal model of obsessive-compulsive disorder (FSMOCD) and the contribution of event-related potential (ERP) studies to this model. First, we considered minor modifications to the FSMOCD model based on neuroimaging and neuropsychological data. We noted the brain areas most affected in this disorder -anterior cingulate cortex (ACC), basal ganglia (BG), and orbito-frontal cortex (OFC) and their related cognitive functions, such as monitoring and inhibition. Then, we assessed the ERPs that are directly related to the FSMOCD, including the error-related negativity (ERN), N200, and P600. Several OCD studies present enhanced ERN and N2 responses during conflict tasks as well as an enhanced P600 during working memory (WM) tasks. Evidence from ERP studies (especially regarding ERN and N200 amplitude enhancement), neuroimaging and neuropsychological findings suggests abnormal activity in the OFC, ACC, and BG in OCD patients. Moreover, additional findings from these analyses suggest dorsolateral prefrontal and parietal cortex involvement, which might be related to executive function (EF) deficits. Thus, these convergent results suggest the existence of a self-monitoring imbalance involving inhibitory deficits and executive dysfunctions. OCD patients present an impaired ability to monitor, control, and inhibit intrusive thoughts, urges, feelings, and behaviors. In the current model, this imbalance is triggered by an excitatory role of the BG (associated with cognitive or motor actions without volitional control) and inhibitory activity of the OFC as well as excessive monitoring of the ACC to block excitatory impulses. This imbalance would interact with the reduced activation of the parietal-DLPC network, leading to executive dysfunction. ERP research may provide further insight regarding the temporal dynamics of action monitoring and executive functioning in OCD.

Prefrontal cortex lesions impair object-spatial integration

How and where object and spatial information are perceptually integrated in the brain is a central question in visual cognition. Single-unit physiology, scalp EEG, and fMRI research suggests that the prefrontal cortex (PFC) is a critical locus for object-spatial integration. To test the causal participation of the PFC in an object-spatial integration network, we studied ten patients with unilateral PFC damage performing a lateralized object-spatial integration task. Consistent with single-unit and neuroimaging studies, we found that PFC lesions result in a significant behavioral impairment in object-spatial integration. Furthermore, by manipulating inter-hemispheric transfer of object-spatial information, we found that masking of visual transfer impairs performance in the contralesional visual field in the PFC patients. Our results provide the first evidence that the PFC plays a key, causal role in an object-spatial integration network. Patient performance is also discussed within the context of compensation by the non-lesioned PFC.

Arithmetic mismatch negativity and numerical magnitude processing in number matching

Background

This study examined the relationship of the arithmetic mismatch negativity (AMN) and the semantic evaluation of numerical magnitude. The first question was whether the AMN was sensitive to the incongruity in numerical information per se, or rather, to the violation of strategic expectations. The second question was whether the numerical distance effect could appear independently of the AMN. Event-related potentials (ERPs) were recorded while participants decided whether two digits were matching or non-matching in terms of physical similarity.

Results

The AMN was enhanced in matching trials presented infrequently relative to non-matching trials presented frequently. The numerical distance effect was found over posterior sites during a 92 ms long interval (236-328 ms) but appeared independently of the AMN.

Conclusions

It was not the incongruity in numerical information per se, but rather, the violation of strategic expectations that elicited the AMN. The numerical distance effect might only temporally coincide with the AMN and did not form an inherent part of it.

Effects of discrepancy between imagined and perceived sounds on the N2 component of the event-related potential

Two experiments were conducted to examine whether the N2 component of the event-related potential (ERP), typically elicited in a S1-S2 matching task and considered to reflect mismatch process, can still be elicited when the S1 was imagined instead of perceived and to investigate how N2 amplitude varied with the degree of S1-S2 discrepancy. Three levels of discrepancy were defined by the degree of separation between the heard (S2) and imagined (S1) sounds. It was found that the N2 was reliably elicited when the perceived S2 differed from the imagined S1, but whether N2 amplitude increased with the degree of discrepancy depended in part on the S1-S2 discriminability (as evidenced by reaction time). Specifically, the effect of increasing discrepancy was attenuated as discriminability increased from hard to easy. These results, together with the dynamic ERP topography observed within the N2 window, suggest that the N2 effect reflects two sequential but overlapping processes: automatic mismatch and controlled detection.

On the differentiation of N2 components in an appetitive choice task: evidence for the revised Reinforcement Sensitivity Theory

Task- and personality-related modulations of the N2 were probed within the framework of the revised Reinforcement Sensitivity Theory (RST). Using an appetitive choice task, we investigated 58 students with extreme scores on the behavioral inhibition system and behavioral approach system (BIS/BAS) scales. The baseline-to-peak N2 amplitude was sensitive to the strength of decision conflict and demonstrated RST-related personality differences. In addition to the baseline N2 amplitude, temporal PCA results suggested two N2 components accounting for a laterality effect and capturing different N2 patterns for BIS/BAS groups with increasing conflict level. Evidence for RST-related personality differences was obtained for baseline-to-peak N2 and tPCA components in the present task. The results support the RST prediction that BAS sensitivity modulates conflict processing and confirm the cognitive-motivational conflict concept of RST.