Late Event-related Potentials Research Articles

Electrophysiological correlates of inhibitory control in children: Relations with prenatal maternal risk factors and child psychopathology.

Inhibitory control plays an important role in children's cognitive and socioemotional development, including their psychopathology. It has been established that contextual factors such as socioeconomic status (SES) and parents' psychopathology are associated with children's inhibitory control. However, the relations between the neural correlates of inhibitory control and contextual factors have been rarely examined in longitudinal studies. In the present study, we used both event-related potential (ERP) components and time-frequency measures of inhibitory control to evaluate the neural pathways between contextual factors, including prenatal SES and maternal psychopathology, and children's behavioral and emotional problems in a large sample of children (N = 560; 51.75% females; Mage = 7.13 years; Rangeage = 4-11 years). Results showed that theta power, which was positively predicted by prenatal SES and was negatively related to children's externalizing problems, mediated the longitudinal and negative relation between them. ERP amplitudes and latencies did not mediate the longitudinal association between prenatal risk factors (i.e., prenatal SES and maternal psychopathology) and children's internalizing and externalizing problems. Our findings increase our understanding of the neural pathways linking early risk factors to children's psychopathology.

Music training is related to late ERP modulation and enhanced performance during Simon task but not Stroop task.

Increasing evidence suggests that music training correlates with better performance in tasks measuring executive function components including inhibitory control, working memory and selective attention. The Stroop and Simon tasks measure responses to congruent and incongruent information reflecting cognitive conflict resolution. However, there are more reports of a music-training advantage in the Simon than the Stroop task. Reports indicate that these tasks may differ in the timing of conflict resolution: the Stroop task might involve early sensory stage conflict resolution, while the Simon task may do so at a later motor output planning stage. We hypothesize that musical experience relates to conflict resolution at the late motor output stage rather than the early sensory stage. Behavioral responses, and event-related potentials (ERP) were measured in participants with varying musical experience during these tasks. It was hypothesized that musical experience correlates with better performance in the Simon but not the Stroop task, reflected in ERP components in the later stage of motor output processing in the Simon task. Participants were classified into high- and low-music training groups based on the Goldsmith Musical Sophistication Index. Electrical brain activity was recorded while they completed visual Stroop and Simon tasks. The high-music training group outperformed the low-music training group on the Simon, but not the Stroop task. Mean amplitude difference (incongruent-congruent trials) was greater for the high-music training group at N100 for midline central (Cz) and posterior (Pz) sites in the Simon task and midline central (Cz) and frontal (Fz) sites in the Stroop task, and at N450 at Cz and Pz in the Simon task. N450 difference peaks occurred earlier in the high-music training group at Pz. Differences between the groups at N100 indicate that music training may be related to better sensory discrimination. These differences were not related to better behavioral performance. Differences in N450 responses between the groups, particularly in regions encompassing the motor and parietal cortices, suggest a role of music training in action selection during response conflict situations. Overall, this supports the hypothesis that music training selectively enhances cognitive conflict resolution during late motor output planning stages.

Four weeks of meditation training improves sustained attention in community-dwelling older adults: a proof-of-concept randomized controlled trial.

Introduction: With our rapidly expanding population of older adults, identifying effective intervention strategies to improve cognitive functioning is an increasing priority. This study sought to examine whether 4weeks of thrice-weekly meditation training can improve attention in older adults, as well as whether such benefits may extend to other domains of cognition as well as mobility. Methods: Forty-three participants (mean age 68years) were randomized into either the focused attention meditation group or the music listening control group (Clinicaltrials.gov ID NCT03417635). Participants completed three 20-minute guided group sessions per week for four consecutive weeks. Our primary outcome measure was behavioural performance on the Sustained Attention to Response Task (SART). Secondary and tertiary outcome measures included event-related potentials (ERPs) during the SART task, measures of executive functioning, and measures of mobility. Results: We found that meditation training significantly improved attention, as demonstrated by improved SART accuracy and changes in N2 ERP amplitude and latency. Discussion: These findings suggest that meditation may lead to changes in attention and underlying cognitive processing in older adults, although a full-scale definitive trial is needed. Future research on the long-term benefits with real world applications is warranted.

Effects of Transcranial Direct Current Stimulation on Potential P300-Related Events and Alpha and Beta EEG Band Rhythms in Parkinson's Disease.

Parkinson's disease is one of the most common neurodegenerative disorders. While a definitive cure for Parkinson's disease remains elusive, a range of treatments are available to slow its progression and counteract its symptoms. Transcranial direct current stimulation (tDCS) represents a non-invasive method to induce brain plasticity. The aim of this study was to examine the effects of two weeks of tDCS on the left dorsolateral prefrontal cortex (DLPFC) on the neurophysiological functioning of Parkinson's patients. Thirty patients aged between 67 and 82 years with Parkinson's disease participated to the experiment. Fifteen underwent tDCS on the left DLPFC, while fifteen underwent sham tDCS. Neurophysiological functions were assessed before and after tDCS using electroencephalogram methods for alpha and beta band rhythms and P300 event-related potential latency. tDCS led to a reduction in the onset latency of the P300 response and an increase in the power spectrum of the alpha and beta band rhythms. This research enhances our understanding of the potential effects of tDCS in the context of Parkinson's disease treatment, as the reduction in P300 latency and the increase in alpha and beta bands are associated with improvements in cognitive aspects.

The levonorgestrel-releasing intrauterine device is related to early emotional reactivity: An ERP study

Despite the evidence of altered emotion processing in oral contraceptive (OC) users, the impact of hormonal intrauterine devices (IUD) on emotional processing remains unexplored. Our study aimed to investigate how behavioural performance and event-related potentials (ERPs) linked with emotion reactivity and its regulation are associated with hormonal profiles of women using different types of hormonal contraception and naturally cycling women. Women using OCs (n = 25), hormonal IUDs (n = 33), and naturally cycling women in their early follicular (NCF, n = 33) or mid-luteal (NCL, n = 28) phase of the menstrual cycle were instructed to view emotional pictures (neutral, low and high negativity) and use cognitive reappraisal to up- or down-regulate negative emotions, while their electroencephalogram was recorded. Participants rated perceived negativity after each picture and their emotional arousal throughout the task. Saliva samples were collected to assess levels of 17β-estradiol, progesterone, and testosterone. As expected, emotional arousal increased throughout the task and correlated positively with perceived negativity. Perceived negativity and the amplitudes of the middle (N2/P3) and later (LPP) latency ERP components increased with increasing stimuli negativity. Emotion regulation modulated perceived negativity and the amplitudes of very late ERP components (parietal and frontal LPP). Moreover, IUD-users showed a higher negative amplitude of the frontal N2 in comparison to all three other groups, with the most consistent differences during up-regulation. Finally, testosterone correlated positively with the N2 peak in IUD-users and NCL women. Overall, our findings suggest that IUD-use and testosterone might be related to altered preconscious processing during the emotion regulation task requiring attention to the stimulus. The study underscores the need for additional research into how different hormonal contraceptives are linked to socio-emotional functioning.

Evaluation of a headphones-fitted EEG system for the recording of auditory evoked potentials and mental workload assessment

Advancements in portable neuroimaging technologies open up new opportunities to gain insight into the neural dynamics and cognitive processes underlying day-to-day behaviors. In this study, we evaluated the relevance of a headphone- mounted electroencephalogram (EEG) system for monitoring mental workload. The participants (N = 12) were instructed to pay attention to auditory alarms presented sporadically while performing the Multi-Attribute Task Battery (MATB) whose difficulty was staged across three conditions to manipulate mental workload. The P300 Event-Related Potentials (ERP) elicited by the presentation of auditory alarms were used as probes of attentional resources available. The amplitude and latency of P300 ERPs were compared across experimental conditions. Our findings indicate that the P300 ERP component can be captured using a headphone-mounted EEG system. Moreover, neural responses to alarm could be used to classify mental workload with high accuracy (over 80%) at a single-trial level. Our analyses indicated that the signal-to-noise ratio acquired by the sponge-based sensors remained stable throughout the recordings. These results highlight the potential of portable neuroimaging technology for the development of neuroassistive applications while underscoring the current limitations and challenges associated with the integration of EEG sensors in everyday-life wearable technologies. Overall, our study contributes to the growing body of research exploring the feasibility and validity of wearable neuroimaging technologies for the study of human cognition and behavior in real-world settings.

Event-related potentials reveal visual episodic memory deficits in patients with temporal lobe epilepsy

ObjectiveTemporal lobe epilepsy (TLE) patients usually suffer from impaired episodic memory (EM), but its underlying electrophysiologic mechanism and impacted cognitive performance are unclear. We aim to investigate the association between episodic memory reserve and physiological measures of memory workload in TLE patients using Event-related potentials (ERP). MethodsA change detection task with image stimuli assesses visual episodic memory. During the memory encoding and decoding phases, the ERP signals were analyzed from twenty-nine TLE patients (twelve with left TLE patients, seventeen with TLE), and thirty healthy controls. Given that EM is a complex process involving many fundamental cognitive processes, the amplitudes and latencies of EM-related ERP (FN400, late positive potential (LPC), and late posterior negativity (LPN)), and the ERP reflecting the fundamental processes (P100, N100, P200, and P300) were calculated. Then we used a three-by-two factorial design on the ERP metrics for interaction and main effects. The correlation analysis among Wechsler Memory Scales-Chinese Revision (WMS-RC) results, behavioral data, and the ERPs was carried out. ResultsThe TLE patients performed worse in WMS-RC and the memory task. The increased P200 and decreased P300 amplitudes were observed in the TLE patients, and LPN was abnormal in only LTLE patients. For EM-related components, differences were observed in both the LTLE and RTLE patients: the lack of the FN400 effect, the lack of the reversed LPC effect, and the reduced FN400. No significant inter-group difference was detected for the latencies of all the ERPs. Additionally, there were significant correlations among WMS-RC scores, behaviors, and some ERP amplitudes. ConclusionsThe impaired EM is linked to the increased P200 and decreased P300 amplitudes. LPN seems to be sensitive to left temporal lobe dysfunction. More importantly, the abnormal old or new effects of the FN400 and LPC, and the reduced FN400 amplitude might be associated with the visual EM deficit in the TLE patients. These findings may assist in the deep understanding of the EM disorder and the evaluation of the side effects of antiepileptic drugs.

Neurocognitive Impairment in Non-Central Nervous System Cancer Survivors

Abstract: Cancer and its treatments entail a profound inflammatory response of the central nervous system (CNS). This intense neurotoxic process can lead to significant neurocognitive impairment even in non-CNS cancers. Few studies have examined this domain, and data available is based on limited designs using neuropsychological assessments comprising self-report or traditional testing batteries that capture basic response data. Here, we leverage cognitive electrophysiology, specifically Event-Related Potentials (ERPs), to examine and delineate neurocognitive impairments in non-CNS cancer survivors. Eleven survivors, who were on average 4.6 years in remission from head and neck cancer and 10 matched healthy controls underwent standardized cognitive and emotional “Go-Nogo” paradigms concomitant to EEG recording. Significant differences in amplitude morphology in the very early ERP components (C1, N1, P1) and middle ERP component (N2), were apparent between non-CNS cancer survivors and controls. Later ERP components (P3, N4) did not show amplitude differences. Non-CNS cancer survivors yielded faster latencies in the early components for pain-related stimuli during the emotional paradigm, albeit tended to yield slower ERP latencies overall across both experiments. These findings suggest that early gating and inhibitory control are dysregulated in non-CNS cancer survivors, which can impact executive functioning and cognitive processing involved in everyday activities for many years post-treatment. The findings do not fully align with ERP morphologies associated with neurocognitive impairment in degenerative conditions (such as dementia and Alzheimer’s disease), affecting later-stage ERP components. Our initial results suggest that (1) cognitive impairments in cancer survivors do not follow a degenerative trajectory, (2) rather are in line with “lesion” related damage (such as stroke, epilepsy), and as such, (3) have the potential for treatments involving neurocognitive plasticity.

Promoting Simple and Engaging Brain-Computer Interface Designs for Children by Evaluating Contrasting Motion Techniques.

There is an increasing focus on using motion in augmentative and alternative communication (AAC) systems. In considering brain-computer interface access to AAC (BCI-AAC), motion may provide a simpler or more intuitive avenue for BCI-AAC control. Different motion techniques may be utilized in supporting competency with AAC devices including simple (e.g., zoom) and complex (behaviorally relevant animation) methods. However, how different pictorial symbol animation techniques impact BCI-AAC is unclear. Sixteen healthy children completed two experimental conditions. These conditions included highlighting of pictorial symbols via both functional (complex) and zoom (simple) animation to evaluate the effects of motion techniques on P300-based BCI-AAC signals and offline (predicted) BCI-AAC performance. Functional (complex) animation significantly increased attentional-related P200/P300 event-related potential (ERP) amplitudes in the parieto-occipital area. Zoom (simple) animation significantly decreased N400 latency. N400 ERP amplitude was significantly greater, and occurred significantly earlier, on the right versus left side for the functional animation condition within the parieto-occipital bin. N200 ERP latency was significantly reduced over the left hemisphere for the zoom condition in the central bin. As hypothesized, elicitation of all targeted ERP components supported offline (predicted) BCI-AAC performance being similar between conditions. Study findings provide continued support for the use of animation in BCI-AAC systems for children and highlight differences in neural and attentional processing between complex and simple animation techniques. https://doi.org/10.23641/asha.24085623.

Dyadic cooperation with human and artificial agents: Event-related potentials trace dynamic role taking during an interactive game.

Humans are highly co-operative and thus cognitively, affectively, and motivationally tuned to pursue shared goals. Yet, cooperative tasks typically require people to constantly take and switch individual roles. Task relevance is dictated by these roles and thereby dynamically changing. Here, we designed a dyadic game to test whether the family of P3 components can trace this dynamic allocation of task relevance. We demonstrate that late positive event-related potential (ERP) modulations not only reflect predictable asymmetries between receiving and sending information but also differentiate whether the receiver's role is related to correct decision making or action monitoring. Furthermore, similar results were observed when playing the game with a computer, suggesting that experimental games may motivate humans to similarly cooperate with an artificial agent. Overall, late positive ERP waves provide a real-time measure of how role taking dynamically shapes the meaning and relevance of stimuli within collaborative contexts. Our results, therefore, shed light on how the processes of mutual coordination unfold during dyadic cooperation.

Enhanced Punishment Responses in Patients With Schizophrenia: An Event-Related Potential Study.

It is well known that abnormal reward processing is a characteristic feature of various psychopathologies including schizophrenia. Reduced reward anticipation has been suggested as a core symptom of schizophrenia. The Monetary Incentive Delay Task (MID) is frequently used to detect reward anticipation. The present study aims to evaluate the amplitude and latency of event-related potential (ERP) P300 in patients with schizophrenia (SCH) compared to healthy controls during the MID task. Twenty patients with SCH and 21 demographically matched healthy controls (HC) were included in the study. ERP P300 amplitude and latency values were compared between groups using an MID task in which reward and loss cues were presented. Relations between P300 and clinical facets were investigated in the patient group. SCH group had enhanced mean P300 amplitudes and delayed peak latency in the punishment condition compared with HC. These higher responses were also associated with negative symptoms. SCH group showed altered reward processing as being more sensitive to loss of reward conditions as firstly evidenced by electrophysiological methods, possibly due to abnormality in various systems including social withdrawal, social defeat, and behavioral inhibition system.

Biological postural oscillations during facial expression of pain in virtual characters modulate early and late ERP components associated with empathy: A pilot study

There is a surge in the use of virtual characters in cognitive sciences. However, their behavioural realism remains to be perfected in order to trigger more spontaneous and socially expected reactions in users. It was recently shown that biological postural oscillations (idle motion) were a key ingredient to enhance the empathic response to its facial pain expression. The objective of this study was to examine, using electroencephalography, whether idle motion would modulate the neural response associated with empathy when viewing a pain-expressing virtual character. Twenty healthy young adults were shown video clips of a virtual character displaying a facial expression of pain while its body was either static (Still condition) or animated with pre-recorded human postural oscillations (Idle condition). Participants rated the virtual human's facial expression of pain as significantly more intense in the Idle condition compared to the Still condition. Both the early (N2–N3) and the late (rLPP) event-related potentials (ERPs) associated with distinct dimensions of empathy, affective resonance and perspective-taking, respectively, were greater in the Idle condition compared to the Still condition. These findings confirm the potential of idle motion to increase empathy for pain expressed by virtual characters. They are discussed in line with contemporary empathy models in relation to human-machine interactions.

Global mapping congruence influences phonological interference: ERP evidence for early and persistent ortho-phonological effects in reading Chinese for meaning.

Phonological interference during written-word meaning judgments occurs in both Chinese and English, suggesting that word-level phonological activation is universal rather than dependent on the sublexical structures that vary with writing systems. To accommodate this universality, we distinguish two sources of phonological congruence between a meaning-bearing orthographic unit (word or character) and other units in the orthographic lexicon: (a) Global congruence between a word (or character) and its orthographic neighbors having the same pronunciation and (b) Local congruence between a word (or character) and its graphic constituents (letters or radicals). Recent evidence by Zhou and Perfetti in 2021 shows a greater role for global than local congruence in covert naming of Chinese characters. We hypothesize this is true also for meaning processing and use behavioral and event-related potential (ERP) measures to test this hypothesis during character meaning judgments. As expected, we found word-level phonological interference in meaning decision times. Further, ERPs detected interference effects related to global congruence at early and mid-latency ERP components; local congruence effects emerged only in interaction with global congruence. A late ERP component (LPC) also showed phonological interference, but no effect on mapping congruence. These time-course results suggest two phases of phonological activation: (a) character identification, influenced mainly by global congruence, as indicated in early and mid-latency ERP components and (b) meaning comparison, influenced only by lexical phonology, as indicated by the LPC component. The early phase of lexical processing is much the same whether meaning or pronunciation is required because it engages ortho-phonological associations that are not easily suppressed. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Sensitivity of late ERP old/new effects in source memory to self-referential encoding focus and stimulus emotionality

In episodic memory, the old/new effect, the contrast of the waveforms elicited by the correctly recognized studied items and the correctly rejected novel items, has been broadly concerned. However, the contribution of self-referential encoding to the old/new effect in source memory (i.e., source-SRE), is far from clarification; further, it remains unclear whether the contribution is susceptible to the factor of stimulus emotionality. To address these issues, adopting the event-related potential (ERP) technique, this study applied words of three types of emotional valences (positive, neutral, vs. negative) in the self-focus vs. external-focus encoding tasks. In the course of the test, four ERP old/new effects were identified: (a) the familiarity- and recollection-reflected mid-frontal effect (FN400) and late positive component (LPC) were both independent of source-SRE and stimulus emotionality; (b) the reconstruction-driven late posterior negativity (LPN) exhibited an adverse pattern of source-SRE and was susceptible to the emotional valence by encoding focus; and (c) the right frontal old/new effect (RFE), reflecting post-retrieval process, exhibited a source-SRE in emotional words. These effects provide compelling evidence for the influences of both stimulus valence and encoding focus on SRE in source memory, especially during the late processes. Further directions considering more perspectives are put forward.

Cognitive control, bedtime patterns, and testing time in female adolescent students: behavioral and neuro-electrophysiological correlates.

Shorter and/or disrupted sleep during adolescence is associated with cognitive and mental health risks, particularly in females. We explored the relationship between bedtime behavior patterns co-varying with Social Jet Lag (SJL) and School Start Times (SST) and neurocognitive performance in adolescent female students. To investigate whether time of day (morning vs. afternoon), early SSTs and days of the school week can be correlated with neurocognitive correlates of sleep insufficiency, we recruited 24 female students aged 16-18 to report sleep logs, and undergo event-related electroencephalographic recordings on Monday, Wednesday, mornings, and afternoons. Using a Stroop task paradigm, we analyzed correlations between reaction times (RTs), accuracy, time of day, day of week, electroencephalographic data, and sleep log data to understand what relationships may exist. Participants reported a 2-h sleep phase delay and SJL. Stroop interference influenced accuracy on Monday and Wednesday similarly, with better performance in the afternoon. For RTs, the afternoon advantage was much larger on Monday than Wednesday. Midline Event-Related Potentials (ERPs) yielded higher amplitudes and shorter latencies on Wednesday morning and Monday afternoon, in time windows related to attention or response execution. A notable exception were delayed ERP latencies on Wednesday afternoon. The latter could be explained by the fact that delta EEG waves tended to be the most prominent, suggesting heightened error monitoring due to accumulating mental fatigue. These findings provide insights into the interaction between SJL and SST and suggest evidence-based criteria for planning when female adolescents should engage in cognitive-heavy school activities such as tests or exams.

LDER: a classification framework based on ERP enhancement in RSVP task

Objective. Rapid serial visual presentation (RSVP) based on electroencephalography (EEG) has been widely used in the target detection field, which distinguishes target and non-target by detecting event-related potential (ERP) components. However, the classification performance of the RSVP task is limited by the variability of ERP components, which is a great challenge in developing RSVP for real-life applications. Approach. To tackle this issue, a classification framework based on the ERP feature enhancement to offset the negative impact of the variability of ERP components for RSVP task classification named latency detection and EEG reconstruction was proposed in this paper. First, a spatial-temporal similarity measurement approach was proposed for latency detection. Subsequently, we constructed a single-trial EEG signal model containing ERP latency information. Then, according to the latency information detected in the first step, the model can be solved to obtain the corrected ERP signal and realize the enhancement of ERP features. Finally, the EEG signal after ERP enhancement can be processed by most of the existing feature extraction and classification methods of the RSVP task in this framework. Main results. Nine subjects were recruited to participate in the RSVP experiment on vehicle detection. Four popular algorithms (spatially weighted Fisher linear discrimination-principal component analysis (PCA), hierarchical discriminant PCA, hierarchical discriminant component analysis, and spatial-temporal hybrid common spatial pattern-PCA) in RSVP-based brain–computer interface for feature extraction were selected to verify the performance of our proposed framework. Experimental results showed that our proposed framework significantly outperforms the conventional classification framework in terms of area under curve, balanced accuracy, true positive rate, and false positive rate in four feature extraction methods. Additionally, statistical results showed that our proposed framework enables better performance with fewer training samples, channel numbers, and shorter temporal window sizes. Significance. As a result, the classification performance of the RSVP task was significantly improved by using our proposed framework. Our proposed classification framework will significantly promote the practical application of the RSVP task.

Conflict in a word-based approach-avoidance task is stronger with positive words.

Valence and motivational direction are linked. We approach good things and avoid bad things, and experience overriding these links as conflicting. Positive valence is more consistently linked with approach than negative valence is linked with avoidance. Therefore, avoiding positive stimuli should produce greater behavioral and neural signs of conflict than approaching negative stimuli. In the present event-related potential study, we tested this assumption by contrasting positive and negative conflict. We used the manikin task, in which we read positive and negative words that they needed to approach and avoid. Consistent with our prediction, positive conflict prolonged reaction times more than negative conflict did. A late (500-1000ms following word onset) event-related potential that we identified as the Conflict slow potential, was only sensitive to positive conflict. The results of this study support the notion that avoiding positive stimuli is more conflicting than approaching negative stimuli. The fact that the conflict slow potential is typically sensitive to response conflict rather than stimulus conflict suggests that the manikin task primarily requires people to override prepotent responses rather than to identify conflicting stimuli. Thus, the present findings also shed light on the psychological processes subserving conflict resolution in the manikin task.

Beyond the N400: Confirmed and Disconfirmed Lexical Predictions in Aging

One of the basic tenets of predictive theories of language processing is that of misprediction cost. Post-N400 positive event-related potential (ERP) components are suitable for studying misprediction cost, but are not adequately described, especially in older adults, who show attenuated N400 ERP effects. We report a secondary analysis of a previously collected EEG data set. Using a picture–word matching paradigm, in which the target word could sometimes be predicted by context and sometimes not, the relationship between aging and late ERP effects was examined. Positivity effects for prediction violations were larger and more extended in older compared with younger adults, independent of context. Younger adults showed frontal negativity effects, indicating frame-shifting processes. Our data suggest that aging does not entail specific declines in prediction. Rather, they indicate that older adults may experience more processing difficulties than younger adults when their expectations are disconfirmed and that multiple mechanisms may be employed during language processing.

Prefrontal EEG slowing, synchronization, and ERP peak latency in association with predementia stages of Alzheimer's disease.

Early screening of elderly individuals who are at risk of dementia allows timely medical interventions to prevent disease progression. The portable and low-cost electroencephalography (EEG) technique has the potential to serve it. We examined prefrontal EEG and event-related potential (ERP) variables in association with the predementia stages of Alzheimer's disease (AD). One hundred elderly individuals were recruited from the GARD cohort. The participants were classified into four groups according to their amyloid beta deposition (A+ or A-) and neurodegeneration status (N+ or N-): cognitively normal (CN; A-N-, n = 27), asymptomatic AD (aAD; A + N-, n = 15), mild cognitive impairment (MCI) with AD pathology (pAD; A+N+, n = 16), and MCI with non-AD pathology (MCI(-); A-N+, n = 42). Prefrontal resting-state eyes-closed EEG measurements were recorded for five minutes and auditory ERP measurements were recorded for 8 min. Three variables of median frequency (MDF), spectrum triangular index (STI), and positive-peak latency (PPL) were employed to reflect EEG slowing, temporal synchrony, and ERP latency, respectively. Decreasing prefrontal MDF and increasing PPL were observed in the MCI with AD pathology. Interestingly, after controlling for age, sex, and education, we found a significant negative association between MDF and the aAD and pAD stages with an odds ratio (OR) of 0.58. Similarly, PPL exhibited a significant positive association with these AD stages with an OR of 2.36. Additionally, compared with the MCI(-) group, significant negative associations were demonstrated by the aAD group with STI and those in the pAD group with MDF with ORs of 0.30 and 0.42, respectively. Slow intrinsic EEG oscillation is associated with MCI due to AD, and a delayed ERP peak latency is likely associated with general cognitive impairment. MCI individuals without AD pathology exhibited better cortical temporal synchronization and faster EEG oscillations than those with aAD or pAD. The EEG/ERP variables obtained from prefrontal EEG techniques are associated with early cognitive impairment due to AD and non-AD pathology. This result suggests that prefrontal EEG/ERP metrics may serve as useful indicators to screen elderly individuals' early stages on the AD continuum as well as overall cognitive impairment.

The Effects of Directional and Non-Directional Stimuli during a Visuomotor Task and Their Correlation with Reaction Time: An ERP Study

Different visual stimuli can capture and shift attention into different directions. Few studies have explored differences in brain response due to directional (DS) and non-directional visual stimuli (nDS). To explore the latter, event-related potentials (ERP) and contingent negative variation (CNV) during a visuomotor task were evaluated in 19 adults. To examine the relation between task performance and ERPs, the participants were divided into faster (F) and slower (S) groups based on their reaction times (RTs). Moreover, to reveal ERP modulation within the same subject, each recording from the single participants was subdivided into F and S trials based on the specific RT. ERP latencies were analysed between conditions ((DS, nDS); (F, S subjects); (F, S trials)). Correlation was analysed between CNV and RTs. Our results reveal that the ERPs' late components are modulated differently by DS and nDS conditions in terms of amplitude and location. Differences in ERP amplitude, location and latency, were also found according to subjects' performance, i.e., between F and S subjects and trials. In addition, results show that the CNV slope is modulated by the directionality of the stimulus and contributes to motor performance. A better understanding of brain dynamics through ERPs could be useful to explain brain states in healthy subjects and to support diagnoses and personalized rehabilitation in patients with neurological diseases.