Parietal Components Research Articles

Frontoparietal Brain Network Plays a Crucial Role in Working Memory Capacity during Complex Cognitive Task.

Recent neurophysiological studies provide inconsistent results of frontoparietal network (FPN) stimulation for altering working memory (WM) capacity. This study aimed to boost WM capacity by manipulating the activity of the FPN via dual-site high-definition transcranial direct current stimulation. Forty-eight participants were randomly assigned to three stimulation groups, receiving either simultaneous anodal stimulation of the frontal and parietal areas (double stimulation), or stimulation of the frontal area only (single stimulation), or the placebo stimulation (sham) to frontal and parietal areas. After the stimulation, we used an operation span task to test memory accuracy, mathematical accuracy, time of calculation and memorizing, and recall response time across the three groups. The results revealed an enhancement of memory accuracy and a reduction of time of calculation in the double stimulation group compared with that in others. In addition, recall response time was significantly decreased in the double and single stimulation groups compared with that in sham. No differences in mathematical accuracy were observed. Our results confirm the pivotal role of the FPN in WM and suggest its functional dissociation, with the frontal component more implicated in the retrieval stage and the parietal component in the processing and retention stages.

Fixation-related potentials during mobile map assisted navigation in the real world: The effect of landmark visualization style.

An often-proposed enhancement for mobile maps to aid assisted navigation is the presentation of landmark information, yet understanding of the manner in which they should be displayed is limited. In this study, we investigated whether the visualization of landmarks as 3D map symbols with either an abstract or realistic style influenced the subsequent processing of those landmarks during route navigation. We utilized a real-world mobile electroencephalography approach to this question by combining several tools developed to overcome the challenges typically encountered in real-world neuroscience research. We coregistered eye-movement and EEG recordings from 45 participants as they navigated through a real-world environment using a mobile map. Analyses of fixation event-related potentials revealed that the amplitude of the parietal P200 component was enhanced when participants fixated landmarks in the real world that were visualized on the mobile map in a realistic style, and that frontal P200 latencies were prolonged for landmarks depicted in either a realistic or abstract style compared with features of the environment that were not presented on the map, but only for the male participants. In contrast, we did not observe any significant effects of landmark visualization style on visual P1-N1 peaks or the parietal late positive component. Overall, the findings indicate that the cognitive matching process between landmarks seen in the environment and those previously seen on a map is facilitated by more realistic map display, while low-level perceptual processing of landmarks and recall of associated information are unaffected by map visualization style.

Electrophysiological correlates of self-related processing in adults with autism.

The term "self-bias" refers to the human propensity to prioritize self- over other-related stimuli and is believed to influence various stages of the processing stream. By means of event-related potentials (ERPs), it was recently shown that the self-bias in a shape-label matching task modulates early as well as later phases of information processing in neurotypicals. Recent claims suggest autism-related deficits to specifically impact later stages of self-related processing; however, it is unclear whether these claims hold based on current findings. Using the shape-label matching task while recording ERPs in individuals with autism can clarify which stage of self-related processing is specifically affected in this condition. Therefore, this study sought to investigate the temporal course of self-related processing in adults with and without autism. Thirty-two adults with autism and 27 neurotypicals completed a shape-label matching task while ERPs were concomitantly recorded. At the behavioral level, results furnished evidence for a comparable self-bias across groups, with no differences in task performance between adults with and without autism. At the ERP level, the two groups showed a similar self-bias at early stages of self-related information processing (the N1 component). Conversely, the autism group manifested a lessened differentiation between self- and other-related stimuli at later stages (the parietal P3 component). In line with recent claims of later phases of self-related processing being altered in autism, we found an equivalent self-bias between groups at an early, sensory stage of processing, yet a strongly diminished self-bias at a later, cognitive stage in adults with autism.

The dissociation of semantically congruent and incongruent cross-modal effects on the visual attentional blink.

Recent studies have found that the sound-induced alleviation of visual attentional blink, a well-known phenomenon exemplifying the beneficial influence of multisensory integration on time-based attention, was larger when that sound was semantically congruent relative to incongruent with the second visual target (T2). Although such an audiovisual congruency effect has been attributed mainly to the semantic conflict carried by the incongruent sound restraining that sound from facilitating T2 processing, it is still unclear whether the integrated semantic information carried by the congruent sound benefits T2 processing. To dissociate the congruence-induced benefit and incongruence-induced reduction in the alleviation of visual attentional blink at the behavioral and neural levels, the present study combined behavioral measures and event-related potential (ERP) recordings in a visual attentional blink task wherein the T2-accompanying sound, when delivered, could be semantically neutral in addition to congruent or incongruent with respect to T2. The behavioral data clearly showed that compared to the neutral sound, the congruent sound improved T2 discrimination during the blink to a higher degree while the incongruent sound improved it to a lesser degree. The T2-locked ERP data revealed that the early occipital cross-modal N195 component (192-228 ms after T2 onset) was uniquely larger in the congruent-sound condition than in the neutral-sound and incongruent-sound conditions, whereas the late parietal cross-modal N440 component (400-500 ms) was prominent only in the incongruent-sound condition. These findings provide strong evidence that the modulating effect of audiovisual semantic congruency on the sound-induced alleviation of visual attentional blink contains not only a late incongruence-induced cost but also an early congruence-induced benefit, thereby demonstrating for the first time an unequivocal congruent-sound-induced benefit in alleviating the limitation of time-based visual attention.

Application of FTIR Microspectroscopy in Oenology: Shedding Light on Cell Wall Composition of Saccharomyces cerevisiae Strains

The evaluation of cell parietal components of yeasts is an important criterium for the selection of wine starters since they play a key role in the vinification process. The aim of this study was to characterize and compare the cell wall composition of four industrial (BM45, D47, EC1118, K1) and three native Saccharomyces cerevisiae (MY8, MY11, PEDRO2000E) wine strains by means of scanning and transmission electron microscopy and ATR-FTIR microspectroscopy. A statistically significant variability in the cell wall thickness and cell diameter was observed among the yeast cells, with native strains showing higher cell diameter values. FTIR microspectroscopy applied on the intact cells without any previous invasive treatment and on the separated cell walls highlighted profound differences among the strains in terms of the overall content of parietal polysaccharides as related to the thickness of the cell walls and in terms of the relative concentration of β-glucans and mannans in the cell walls. The strains EC1118, MY11, and PEDRO2000E showed a higher overall content of β-glucans and mannans, whose lower relative concentration in PEDRO2000E was compensated by a thicker cell wall; BM45 and D47 were characterized by a high relative concentration of polysaccharides in a thinner wall, while K1 and MY8 displayed a low relative concentration of polysaccharides. ATR-FTIR microspectroscopy allows identifying polysaccharide-rich yeast strains and can become a smart option for the selection of starter cultures to be used in oenology and for other applications in food industry, thanks to the interesting technological properties of parietal polysaccharides.Graphical

Analgesic efficacy of Transverse Abdomen Plane Block in Kidney Transplantation

Introduction: The transversus abdominis plane anesthetic block (TAP Block) technique was first introduced in 2001 by Rafi to promote anterolateral abdominal wall analgesia. This block involves the T7-L1, subcostal, ilioinguinal and iliohypogastric nerves. Kidney transplant recipients are candidates for this blocking method, since the surgical access to the kidney implant allows exposure of the nerve plexus, T7-L1, responsible for the parietal component of pain, allowing its blockade under direct vision. Objectives:To analyze the analgesic efficacy of TAP Block x local infiltration in kidney transplantation in three different moments: upon awakening after 6h and with 24h of rest and 24h of sitting down using the visual analogue pain scale for evaluation. Methods:Prospective, randomized, double-blind study with two groups, the control group: standard balanced general anesthesia and infusion of local anesthetic in the subcutaneous tissue; and the experimental: balanced general anesthesia and local anesthetic infusion (TAP Block) directly through the surgical access. These groups were evaluated postoperatively by a researcher who was unaware of the type of procedure the patient underwent. Candidates to participate in the study were patients from the General Transplant Unit, located at the Instituto de Medicina Integral Prof. Fernando Figueira (IMIP). Results: 45 patients were allocated in the study. After exclusions, 20 patients in the control group and 21 patients in the experimental group were analyzed. No clinical or demographic characteristics were statistically significant. In the control group, 72.6 % reported moderate/severe pain upon awakening, while moderate and severe pain was present in only 7.4 % of the experimental group, with p<0.001. In the 06h assessment, there was a significant difference in relation to moderate/severe pain scores between groups: 59.8 % in the control and 15 % for the experimental group, respectively, with p < 0.007. There was no statistical difference between the groups in the static and dynamic evaluation in the 24h period. Conclusion: Balanced general anesthesia associated with TAP Block proved to be effective in reducing moderate and severe pain scores in the initial moments: upon awakening, and after 6h, being, as expected, less effective in the 24-hour evaluation.

With or without Feedback?-How the Presence of Feedback Affects Processing in Children with Developmental Language Disorder.

Language acquisition depends on the ability to process and learn probabilistic information, often through the integration of performance feedback. Children with developmental language disorder (DLD) have demonstrated weaknesses in both probabilistic learning and feedback processing, but the individual effects of each skill are poorly understood in this population. This study examined school-aged children with DLD (n = 29) and age- and gender-matched children with typical development (TD; n = 44) on a visual probabilistic classification learning task presented with and without feedback. In the feedback-based version of the task, children received performance feedback on a trial-by-trial basis during the training phase of the task. In the feedback-free version, children responded after seeing the correct choice marked with a green border and were not presented with feedback. Children with TD achieved higher accuracy than children with DLD following feedback-based training, while the two groups achieved similar levels of accuracy following feedback-free training. Analyses of event-related potentials (ERPs) provided insight into stimulus encoding processes. The feedback-free task was dominated by a frontal slow wave (FSW) and a late parietal component (LPC) which were not different between the two groups. The feedback-based task was dominated by a parietal slow wave (PSW) and an LPC, both of which were found to be larger in the TD than in the DLD group. In combination, results suggest that engagement with feedback boosts learning in children with TD, but not in children with DLD. When the need to process feedback is eliminated, children with DLD demonstrate behavioral and neurophysiological responses similar to their peers with TD.

Neurocognitive effects of binge drinking on verbal episodic memory. An ERP study in university students.

Background: Verbal memory may be affected by engagement in alcohol binge drinking during youth, according to the findings of neuropsychological studies. However, little is known about the dynamics of the neural activity underlying this cognitive process in young, heavy drinkers. Aims: To investigate brain event-related potentials associated with cued recall from episodic memory in binge drinkers and controls. Methods: Seventy first-year university students were classified as binge drinkers (32: 17 female) or controls (38: 18 female). The participants completed a verbal paired associates learning task during electroencephalogram (EEG) recording. ERPs elicited by old and new word pairs were extracted from the cued-recall phase of the task by using Principal Component Analysis. Subjects also performed a standardized neuropsychological verbal learning test. Results: Two of the three event-related potentials components indicating old/new memory effects provided evidence for anomalies associated with binge drinking. The old/new effects were absent in the binge drinkers in the two subsequent posterior components, identified with the late parietal component and the late posterior negativity The late frontal component revealed similar old/new effects in both groups. Binge drinkers showed similar behavioural performance to controls in the verbal paired associates task, but performed poorly in the more demanding short-term cued-recall trial of a neuropsychological standardized test. Conclusion: Event-related potentials elicited during a verbal cued-recall task revealed differences in brain functioning between young binge drinkers and controls that may underlie emergent deficits in episodic memory linked to alcohol abuse. The brain activity of binge drinkers suggests alterations in the hippocampal - posterior parietal cortex circuitry subserving recognition and recollection of the cue context and generation of the solution, in relation to verbal information shallowly memorised.

Parietal Infiltration for Postoperative Analgesia

The parietal component of pain occupies an important place in the management of postoperative analgesia. Parietal infiltration is a technique that fits into a concept of multimodal analgesia using several analgesic products simultaneously. This simple and reliable technique makes it possible to reduce the use of opioids and therefore their adverse effects; without increasing the risk of infection. It reduces the length of hospitalization.

THE CHOICE OF A PERSONALIZED METHOD IN THE DIAGNOSTICS OF BREAST CANCER IN A CYST BY MEANS OF HYBRID TECHNOLOGIES UNDER ULTRASOUND NAVIGATION

The article presents the results of the use of a new improved method of cytologic diagnostics of cancer in a breast cyst by applying hybrid technologies. By using our new created method with the application of ozone-oxygen mixture, unlike the traditional method of fine needle aspiration biopsy of breast cysts with a solid parietal component, the probability of obtaining unaltered atypical cells in the punctate in the presence of malignization increases, thereby promoting the informativeness and sensitivity of this diagnostic method.

Nutritional aspects of the main natural fodder resources in the locality of Ngouye in Senegal

The study was carried out in the locality of Ngouye which is an agro-pastoral area located in the Karffine region in Senegal. The breeding that is practiced is of the extensive type on natural pastures. The study aims to know the nutritional aspects of woody fodder found in the area. During our ethnobotanical survey, we identified 28 woody species, 23 of which are fodder. All species showed high levels of nitrogenous matter (MAT) ranging from 15.66% to 18.21% dry matter (DM). However, among these 23 species, 9 are considered to be better fodder. These 9 species have much greater dry matter ingestion and digestion capacities and low parietal components, in particular lignin and cellulose. These fodder species are Eucalyptus Alba, Securidaca longepedunculata, Acacia ataxacantha, Adansonia digitata, Azadirachta indica, Balanites aegyptiaca, Combretum glutinosum, Anogeissus leiocarpus, and Acacia nilotica. The calcium phosphorus imbalance with respective averages of 0.17 and 1.16 shows that most species are phosphorus deficient.

Developmental osteology of Ictalurus punctatus and Noturus gyrinus (Siluriformes: Ictaluridae) with a discussion of siluriform bone homologies

Abstract The skeleton of Siluriformes is characterized by several autapomorphies, including secondary absence, extreme modification, and purported fusion of several ossifications. Although well documented in adults, information on skeletal development in catfishes is relatively sparse and typically focused on particular regions of the skeleton (e.g., Weberian apparatus). To further our understanding of the siluriform skeleton, I document the development of the entire skeleton in two ictalurid species, Ictalurus punctatus (channel catfish) and Noturus gyrinus (tadpole madtom) from five days pre-hatch to adult. I reexamine the homologies of bones previously hypothesized to represent compound elements in catfishes as well as an additional element only known to occur in some ictalurids. Development of the skeleton is complete in I. punctatus at 22.4 mm SL and almost complete in N. gyrinus (except dorsal- and anal-fin distal radials) at 14.1 mm SL. No signs of ontogenetic fusion were observed in any of the purported compound elements. Previous hypotheses of the homology of these elements and of additional ossifications are reviewed in light of developmental information obtained herein. No dermal parietal component is present at any stage in the so-called parieto-supraoccipital. The bone is the supraoccipital which ossifies from two lateral centers of ossification which later fuse, rather than from a median center. The ‘posttemporo-supracleithrum’ originates from a single center of ossification and represents the supracleithrum. The posttemporal is present in ictalurids and many other catfishes as a canal-bearing bone between the supracleithrum and the pterotic, a bone sometimes identified as the extrascapular. The extrascapular is missing in catfishes. Ictalurids have an additional dermal bone above the posttemporal, which is either an independently ossifying fragment of the posttemporal or a neoformation restricted to some members of this family. The single chondral bone of the pectoral girdle originates from a single center of ossification that represents the coracoid. The scapula is missing in catfishes. Dorsal-fin distal radial 2 is absent in catfishes and the foramen of dorsal-fin spine 2 is formed from modifications to the base of the fin-ray itself. Unlike loricarioid catfishes, the urohyal of ictalurids originates solely as an ossification of the sternohyoideus tendons. The anteriormost infraorbital element ossifies from a single center of ossification around the infraorbital sensory canal and represents the lacrimal. The antorbital is missing in catfishes. Finally, skeletal development of I. punctatus is compared to that available for other otophysans, including the cypriniforms Danio rerio and Enteromius holotaenia and the characiform Salminus brasiliensis.

Effects of Core Disgust and Moral Disgust on Moral Judgment: An Event-Related Potential Study.

Core disgust is elicited by physical or chemical stimuli, while moral disgust is evoked by abstract violations of moral norms. Although previous studies have pointed out these two types of disgust can affect behavior and spatial dimensions of moral judgment, less is known about how moral and core disgust affect the temporal neural processing of moral judgment. In addition, whether moral and core disgust are only related to purity-based moral judgment or all kinds of moral judgment is still controversial. This study aimed to explore how core and moral disgust affect the neural processing of purity-based moral judgment by using affective priming and moral judgment tasks. The behavioral results showed that the severity of moral violation of non-purity ones is higher than purity ones. The event-related potentials (ERP) results mainly revealed that earlier P2 and N2 components, which represent the automatic moral processes, can differentiate neutral and two types of disgust rather than differentiating moral domain, while the later N450, frontal, and parietal LPP components, which represent the conflict detection and, later, cognitive processing can differentiate the purity and non-purity ones rather than differentiating priming type. Moreover, core and moral disgust priming mainly differed in the purity-based moral processing indexed by parietal LPP. Our findings confirmed that the disgusting effect on moral judgments can be explained within the framework of dual-process and social intuitionist models, suggesting that emotions, including core and moral disgust, played an essential role in the automatic intuition process. The later parietal LPP results strongly supported that core disgust only affected the purity-based moral judgment, fitting the primary purity hypothesis well. We show how these theories can provide novel insights into the temporal mechanisms of moral judgment.

The role of temporal distance of the events on the spatiotemporal dynamics of mental time travel to one\u2019s personal past and future

Mental time travel to personal past and future events shows remarkable cognitive and neural similarities. Both temporalities seem to rely on the same core network involving episodic binding and monitoring processes. However, it is still unclear in what way the temporal distance of the simulated events modulates the recruitment of this network when mental time-travelling to the past and the future. The present study explored the electrophysiological correlates of remembering and imagining personal events at two temporal distances from the present moment (near and far). Temporal distance modulated the late parietal component (LPC) and the late frontal effect (LFE), respectively involved in episodic and monitoring processes. Interestingly, temporal distance modulations differed in the past and future event simulation, suggesting greater episodic processing for near as opposed to far future situations (with no differences on near and far past), and the implementation of greater post-simulation monitoring processes for near past as compared to far past events (with high demands on both near and far future). These findings show that both past and future event simulations are affected by the temporal distance of the events, although not exactly in a mirrored way. They are discussed according to the increasing role of semantic memory in episodic mental time travel to farther temporal distances from the present.

The interplay between audiovisual temporal synchrony and semantic congruency in the cross-modal boost of the visual target discrimination during the attentional blink.

The visual attentional blink can be substantially reduced by delivering a task‐irrelevant sound synchronously with the second visual target (T2), and this effect is further modulated by the semantic congruency between the sound and T2. However, whether the cross‐modal benefit originates from audiovisual interactions or sound‐induced alertness remains controversial, and whether the semantic congruency effect is contingent on audiovisual temporal synchrony needs further investigation. The current study investigated these questions by recording event‐related potentials (ERPs) in a visual attentional blink task wherein a sound could either synchronize with T2, precede T2 by 200 ms, be delayed by 100 ms, or be absent, and could be either semantically congruent or incongruent with T2 when delivered. The behavioral data showed that both the cross‐modal boost of T2 discrimination and the further semantic modulation were the largest when the sound synchronized with T2. In parallel, the ERP data yielded that both the early occipital cross‐modal P195 component (192–228 ms after T2 onset) and late parietal cross‐modal N440 component (424–448 ms) were prominent only when the sound synchronized with T2, with the former being elicited solely when the sound was further semantically congruent whereas the latter occurring only when that sound was incongruent. These findings demonstrate not only that the cross‐modal boost of T2 discrimination during the attentional blink stems from early audiovisual interactions and the semantic congruency effect depends on audiovisual temporal synchrony, but also that the semantic modulation can unfold at the early stage of visual discrimination processing.

Measuring Mental Workload Using ERPs Based on FIR, ICA, and MARA

Mental workload is considered to be strongly linked to human performance, and the ability to measure it accurately is key for balancing human health and work. In this study, brain signals were elicited by mental arithmetic tasks of varying difficulty to stimulate different levels of mental workload. In addition, a finite impulse response (FIR) filter, independent component analysis (ICA), and multiple artifact rejection algorithms (MARAs) were used to filter event-related potentials (ERPs). Then, the data consisting of ERPs, subjective ratings of mental workload, and task performance, were analyzed through the use of variance and Spearman’s correlation during a simulated computer task. We found that participants responded faster and performed better in the easy task condition, followed by the medium and high-difficulty conditions, which verifies the validity of the ERP filtering. Moreover, larger P2 and P3 waveforms were evoked as the task difficulty increased, and a higher task difficulty elicited a more enhanced N300. Correlation analysis revealed a negative relationship between the amplitude of P3 and the subjective ratings, and a positive relationship between the P3 amplitude and accuracy. The results presented in this paper demonstrate that a combination of FIR, ICA, and MARA methods can filter ERPs in the non-invasive real-time measurement of workload. Additionally, frontocentral P2, N3, and parietal P3 components showed differences between genders. The proposed measurement of mental workload can be useful for real-time identification of mental states and can be applied to human–computer interaction in the future.

Changes of attention-related brain activity over 6 months after acute organophosphate pesticide poisoning: a prospective follow-up study

Context Ingestion of organophosphate (OP) pesticides is a common method of self-harm in developing countries. Apart from acute cholinergic effects, limited evidence implicates OP poisoning in long-term neurocognitive deficits. However, prospective neurophysiological evidence of long-term deficits is scarce in humans. We aimed to determine long-term cognitive changes of acute OP pesticide self-poisoning in a prospective follow-up study, using event-related potentials (ERPs), an electroencephalographic index of cognitive functioning. Methods We recruited 203 patients (147 men) hospitalised with OP pesticide ingestion (OP group; all had significant erythrocyte cholinesterase inhibition) and 50 patients (23 men) with paracetamol overdose (control group) as a means of self-harm. We recorded their ERPs and behavioural performance in a selective attention task at three post-exposure time points: on discharge from hospital (around 14 days post-ingestion), 6 weeks and 6 months post-ingestion. We compared the reaction time and ERP components of the two groups at each time point, adjusting for sex, age, education and comorbid depression in multiple regression models. Results OP group had significantly slower reaction times than the control group on discharge and at 6 weeks, but not at 6 months. On discharge, the OP group also showed significantly prolonged latency of the parietal P3b component, signifying delayed attentional processing. P3b amplitudes were also significantly smaller in the OP group on discharge and at 6 months. Within the OP group, greater clinical severity of poisoning was associated with smaller P3b amplitudes. Early pre-attentive cortical processing (as indexed by N1 ERP component) showed no significant intergroup differences. Conclusions Acute OP pesticide poisoning was associated with impaired behavioural and neurophysiological indices of selective attention. These deficits outlast the cholinergic phase of intoxication. The neurobehavioral impairment disappears over months, but neurophysiological deficits seem to last even after 6 months. This impairment could potentially compromise the performance and safety of patients for months following clinical recovery.

Alerting network alteration in isolated rapid eye movement sleep behavior disorder patients with mild cognitive impairment

ObjectiveMild cognitive impairment (MCI) was found in 30–50% of the isolated REM sleep behavior disorder (iRBD) patients. Furthermore, it is known that patients with Parkinson's disease have attention network defects. Given that iRBD is known to be the prodromal disease of α-synucleinopathies, our aim was to investigate whether there are attention network dysfunctions in iRBD patients following the presence of MCI. Methods14 healthy controls, 48 iRBD patients, 24 with MCI and 24 without MCI, were included in this study. Attention network task (ANT) was used to assess alerting, orienting, and executive control networks. Event-related potentials (ERPs) and behavioral performances were recorded during the ANT. Parietal N1 and P3 components were analyzed to find effects of the three attention networks. ResultsIRBD patients without MCI showed neuropsychological, behavioral, and ERP results similar to those of healthy controls. On the other hand, iRBD patients with MCI showed a general decline in cognitive domains with no alerting effect (controls, p = 0.043; iRBD-noMCI, p = 0.014; iRBD-MCI, p = 0.130) while preserving orienting and executive control effect. Furthermore, iRBD patients with MCI had impairments in executive function and verbal memory domains, compared to iRBD patients without MCI. ConclusionsOur findings indicate that when cognition is reduced to MCI levels in iRBD patients, the attention network, especially the alerting component, is impaired. The attention network and cognition, on the other hand, can be preserved in iRBD patients due to the compensatory mechanism.

Response inhibition and memory updating in the count/nocount task: an ERP study.

The present study aimed to separate the neural activities between response inhibition and memory updating processes in the Count/Nocount task. Memory load was manipulated to investigate the memory updating process. Within each trial, participants were asked to count/withhold counting the number of O/X letters in the Count/Nocount task. The participants were asked to silently add 1 if a Count letter was presented in the low load condition, and add 2 in the high load condition. Data from 28 healthy participants showed that: (1) in both high load and low load conditions, the latencies of P2 and N2 components were shorter for the Nocount than Count trials, indicating faster attentional orienting and conflict monitoring processes for the Nocount stimuli (i.e., inhibition processes triggered by the Nocount stimuli against those response execution processes triggered by Count stimuli); (2) more positive frontal P3 amplitudes were evoked for the Nocount relative to the Count stimuli, indicating a more intensive response inhibition process for the Nocount trials; (3) a more positive parietal P3 component was evoked for the low load relative to high load condition, indicating a more intensive working memory updating process for the high load condition. This load effect was absent for the frontal P3 component, suggesting that the frontal P3 might not be associated with the memory updating process. In sum, both the cognitive inhibition process (reflected by the frontal P3 component) and working memory updating process (reflected by the parietal P3 component) appear to be involved in the Count/Nocount task.

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.