P300 Amplitude Research Articles

You're Beautiful When You Smile: Event-Related Brain Potential (ERP) Evidence of Early Opposite-Gender Bias in Happy Faces.

Studies of social cognition have shown gender differences regarding human face processing. One interesting finding is the enhanced processing of opposite-gender faces at different time stages, as revealed by event-related brain potentials. Crucially, from an evolutionary perspective, such a bias might interact with the emotional expression of the face. To investigate this, 100 participants (50 female, 50 male) completed an expression-detection task while their EEG was recorded. In three blocks, fearful, happy and neutral faces (female and male) were randomly presented, with participants instructed to respond to only one predefined target expression level in each block. Using linear mixed models, we observed both faster reaction times as well as larger P1 and late positive potential (LPP) amplitudes for women compared to men, supporting a generally greater female interest in faces. Highly interestingly, the analysis revealed an opposite-gender bias at P1 for happy target faces. This suggests that participants' attentional templates may include more opposite-gender facial features when selectively attending to happy faces. While N170 was influenced by neither the face nor the participant gender, LPP was modulated by the face gender and specific combinations of the target status, face gender and expression, which is interpreted in the context of gender-emotion stereotypes. Future research should further investigate this expression and attention dependency of early opposite-gender biases.

Impact of early refined nursing program on prognosis of middle-aged and elderly patients with cognitive dysfunction combined with cerebral infarction.

Cerebral infarction is a local or extensive necrosis of brain tissue. Subsequently, the corresponding neurological deficits appear. The incidence of cerebrovascular diseases in China is increasing gradually. After the onset of cerebrovascular disease, the most common sequelae include movement disorders, language disorders, and cognitive dysfunction. To investigate the effect of early refined nursing program on the prognosis of middle-aged and elderly patients with cerebral infarction combined with cognitive dysfunction. A retrospective study was conducted to divide 60 patients with cerebral infarction and cognitive impairment into an experimental group (n = 32) and a control group (n = 28). The experimental group received early intensive care every day, and the control group received daily routine care. The scores of the Mini-Mental State Examination (MMSE) and the Trail Making Test (TMT), as well as the latency and amplitude of the event-related potential P300, were used as main indicators to evaluate changes in cognitive function, and changes in BDNF, TGF-β, and GDNF expression were used as secondary indicators. Both groups experienced notable enhancements in MMSE scores, with the experimental group demonstrating higher scores than the control group (experimental: 28.75 ± 2.31; control: 25.84 ± 2.87). Moreover, reductions in TMT-A and TMT-B scores were observed in both groups (experimental: TMT-A 52.36 ± 6.18, TMT-B 98.47 ± 10.23; control: TMT-A 61.48 ± 7.92, TMT-B 112.63 ± 12.55), with the experimental group displaying lower scores. P300 Latency decreased (experimental: 270.63 ms ± 14.28 ms; control: 285.72 ms ± 16.45 ms), while amplitude increased (experimental: 7.82 μV ± 1.05 μV; control: 6.35 μV ± 0.98 μV) significantly in both groups, with superior outcomes in the experimental cohort. Additionally, the levels of the growth factors BDNF, TGF-β1, and GDNF surged (experimental: BDNF 48.37 ng/mL ± 5.62 ng/mL, TGF-β1 52.14 pg/mL ± 4.28 pg/mL, GDNF 34.76 ng/mL ± 3.89 ng/mL; control: BDNF 42.58 ng/mL ± 4.73 ng/mL, TGF-β1 46.23 pg/mL ± 3.94 pg/mL, GDNF 30.25 ng/mL ± 2.98 ng/mL) in both groups, with higher levels in the experimental group. For middle-aged and elderly patients with cerebral infarction and cognitive dysfunction, early refined nursing can significantly improve their cognitive function and prognosis.

Model-based Mind Wandering in Older Adults: Age Differences in the Behavioral and Electrophysiological Correlates of Subjective and Objective Measures of Mind Wandering.

Mind wandering is typically characterized as a failure of attentional control, yet despite age-related executive function deficits, older adults typically report less mind wandering than younger adults during cognitive tasks and in daily life. Self-reported mind wandering episodes usually result in similar behavioral detriments in younger and older adults (e.g., greater RT variability, more task errors). However, the relatively few studies investigating the neural correlates of mind wandering and aging have revealed mixed findings, possibly because they typically rely on infrequent thought probes and, therefore, few trials for neural analyses. In the current study, we propose a method to recover more task data by categorizing trials from a commonly used sustained attention to response task according to RT variability. Behavioral data (n = 49 younger; n = 40 older) revealed that compared with younger adults, older adults reported fewer mind wandering episodes, but showed similar behavioral impacts thereof. Furthermore, in both age groups, subjective reports of mind wandering predicted the more objective sorting of trials into "on-" and "off-task" according to RT variability. Using these objectively sorted trials, we investigated two commonly reported EEG measures of mind wandering (diminished P1 and P3 amplitude) in 26 younger and 24 older adults. Although the P1 did not differ between on- and off-task trials for either group, the P3 was diminished for off-task trials in both age groups (albeit significantly less in older adults) suggesting preserved perceptual but reduced higher-order processing during off-task periods in both groups.

Performing a Motor Action Enhances Social Reward Processing and Modulates the Neural Processing of Predictive Cues.

Associative learning affects many areas of human behavior. Recently, we showed that the neural response to monetary reward is enhanced by performing an action, suggesting interactions between neural systems controlling motor behavior and reward processing. Given that many psychiatric disorders are associated with social anhedonia, a key open question is whether such effects generalize to social rewards, and in how far they affect associative learning. We developed a novel task in which participants (n = 66) received social reward feedback and social punishment either by pressing a button or waiting. Predictive cues were linked to feedback valence with 80% accuracy. Using EEG, we measured the neural response to both predictive cues and social feedback. We found enhanced reward positivity for social reward preceded by an action, and an enhanced N2 for cues predicting negative feedback. Cue-locked P3 amplitude was reduced for cues associated with negative feedback in passive trials only, showing a modulation of outcome anticipation by performing a motor action. This was supported by connectivity analyses showing stronger directed theta synchronization, in line with increased top-down modulation of attention, in active compared with passive trials. These findings suggest that actively obtaining social feedback enhances reward sensitivity and modulates outcome anticipation.

Study on the influence of food emulsion components on its lubrication characteristics and smooth perception

Due to the increasing risk of obesity and cardiovascular diseases caused by high-fat diets, low-fat foods have become a priority demand for consumers’ health. However, the smoothness perception and scientific assessment methods of the existing low-fat foods should be improved. In this study, three food emulsions were prepared, and their lubrication characteristics, sensory evaluation of smoothness, and electroencephalogram (EEG) signals were assessed to preliminarily investigate the effects of food emulsion components on their above characteristics. The results showed that fat substitute (FSU) and fat could significantly reduce coefficient of friction (CoF) of the food emulsions, with average CoF reduced by 28% and 63% compared to the original food emulsions. In addition, fat-enriched food emulsions continued to exhibit excellent lubrication characteristics after adding artificial saliva, with an average CoF reduced by 31.1% compared to that of the food emulsions without artificial saliva. Both FSU and fat improved the smoothness of food emulsions, and the lubricating properties of fat were more pronounced, with fat-enriched food emulsion which could provide a substantial improvement in smoothness compared to the fat-free food emulsion. Comparison of subjects’ EEG signals revealed that food emulsion with lower CoF and higher smoothness triggered higher P3 amplitudes and longer latencies. These findings provide better insights into the scientific evaluation of food texture and the development of low-fat foods.

The association between insomnia symptoms and cognitive flexibility among undergraduates: An event-related potential study

ObjectiveTo explore the association between insomnia symptoms and cognitive flexibility among undergraduates, along with its potential neural mechanisms. MethodA total of 102 participants were divided into insomnia (n = 55) and control (n = 47) groups based on sleep status. Cognitive flexibility was assessed using the Cognitive Flexibility Inventory (CFI) and the Number-Letter Task (N-L task). EEG data were recorded during the N-L task. ResultsThe insomnia group exhibited lower CFI scores and higher switch costs in reaction time and accuracy compared to the control group. ERP analysis showed differences in P2, N2, and P3 component amplitudes between the two groups, with reduced N2 amplitude in the insomnia group under repeat trials. Time-frequency analysis revealed larger theta band event related synchronization in the frontal region and smaller theta band ERS in the parietal region under switch trials in the control group; the alpha band event-related desynchronization in the parietal region under repeat trials was significantly smaller in the control group compared to switch trials. ConclusionCompared to undergraduates with normal sleep, those with insomnia symptoms exhibited reduced cognitive flexibility, which may be associated with some alterations in brain electrophysiological activities.

Towards electrophysiological measurement of presence in virtual reality through auditory oddball stimuli

Objective. Presence is an important aspect of user experience in virtual reality (VR). It corresponds to the illusion of being physically located in a virtual environment (VE). This feeling is usually measured through questionnaires that disrupt presence, are subjective and do not allow for real-time measurement. Electroencephalography (EEG), which measures brain activity, is increasingly used to monitor the state of users, especially while immersed in VR. Approach. In this paper, we present a way of evaluating presence, through the measure of the attention dedicated to the real environment via an EEG oddball paradigm. Using breaks in presence, this experimental protocol constitutes an ecological method for the study of presence, as different levels of presence are experienced in an identical VE. Main results. Through analysing the EEG data of 18 participants, a significant increase in the neurophysiological reaction to the oddball, i.e. the P300 amplitude, was found in low presence condition compared to high presence condition. This amplitude was significantly correlated with the self-reported measure of presence. Using Riemannian geometry to perform single-trial classification, we present a classification algorithm with 79% accuracy in detecting between two presence conditions. Significance. Taken together our results promote the use of EEG and oddball stimuli to monitor presence offline or in real-time without interrupting the user in the VE.

Attentional resource consumption of verbal-humor processing: An ERP study

As a high-demanding mental activity with both cognitive and emotional factors, verbal-humor processing consumes more attentional resources than non-humor processing, which has been demonstrated by behavioral studies, but little has been examined at a real-time scale. Based on the three-stage model (incongruity detection, incongruity resolution, and mirth), the current study used event-related potential (ERP) and event-related oscillation (ERO) to explore the attentional resource consumption of verbal-humor processing by employing a dual-task paradigm in which sentence comprehension (humorous, positive, neutral) was the primary task and arithmetical calculation (simple, difficult) was the secondary task.Participants’ (N=38) behavioral performance and ERP/ERO measures in two tasks were analyzed. ERP results of verbal-humor processing revealed significantly larger LAN, LLAN, and LPP activation, which indexed three stages. ERO results showed significant beta power changes in the detection stage and theta changes in the resolution and mirth stages. The behavioral data indicated that the Reaction Times (RTs) of the arithmetical task following verbal-humor processing were longer than those following non-humorous positive and neutral ones. The ERP results of arithmetical calculation found that the calculations following verbal-humor processing elicited significantly greater P2, P3b, and positive slow wave amplitudes than those following the other two processings, which reflected more resource allocation in the calculation to compensate for the resource preemption of verbal-humor processing. In addition, the calculation following positive sentence exhibited a greater ERP amplitude in the relatively early P2 time intervals than that following the neutral sentences. Collectively, the behavioral, ERP, and ERO results concurrently confirmed that verbal-humor processing consumed more attentional resources compared with non-humorous counterparts, and moreover, the comparison of ERP following humorous and positive sentences suggested that the processing of the cognitive factor consumes more attentional resources than the emotional factor although both factors play a role in the process.

Gender effect in human-machine communication: a neurophysiological study.

This study aimed to investigate the neural mechanism by which virtual chatbots' gender might influence users' usage intention and gender differences in human-machine communication. Event-related potentials (ERPs) and subjective questionnaire methods were used to explore the usage intention of virtual chatbots, and statistical analysis was conducted through repeated measures ANOVA. The findings of ERPs revealed that female virtual chatbots, compared to male virtual chatbots, evoked a larger amplitude of P100 and P200, implying a greater allocation of attentional resources toward female virtual chatbots. Considering participants' gender, the gender factors of virtual chatbots continued to influence N100, P100, and P200. Specifically, among female participants, female virtual chatbots induced a larger P100 and P200 amplitude than male virtual chatbots, indicating that female participants exhibited more attentional resources and positive emotions toward same-gender chatbots. Conversely, among male participants, male virtual chatbots induced a larger N100 amplitude than female virtual chatbots, indicating that male participants allocated more attentional resources toward male virtual chatbots. The results of the subjective questionnaire showed that regardless of participants' gender, users have a larger usage intention toward female virtual chatbots than male virtual chatbots. Our findings could provide designers with neurophysiological insights into designing better virtual chatbots that cater to users' psychological needs.

Effects of Transcutaneous Auricular Vagus Nerve Stimulation on the P300: Do Stimulation Duration and Stimulation Type Matter?

Non-invasive transcutaneous auricular vagus nerve stimulation (taVNS) has attracted increasing interest as a neurostimulation tool with potential applications in modulating cognitive processes such as attention and memory, possibly through the modulation of the locus-coeruleus noradrenaline system. Studies examining the P300 brain-related component as a correlate of noradrenergic activity, however, have yielded inconsistent findings, possibly due to differences in stimulation parameters, thus necessitating further investigation. In this event-related potential study involving 61 participants, therefore, we examined how changes in taVNS parameters, specifically stimulation type (interval vs. continuous stimulation) and duration, influence P300 amplitudes during a visual novelty oddball task. Although no effects of stimulation were found over the whole cluster and time window of the P300, cluster-based permutation tests revealed a distinct impact of taVNS on the P300 response for a small electrode cluster, characterized by larger amplitudes observed for easy targets (i.e., stimuli that are easily discernible from standards) following taVNS compared to sham stimulation. Notably, our findings suggested that the type of stimulation significantly modulated taVNS effects on the P300, with continuous stimulation showing larger P300 differences (taVNS vs. sham) for hard targets and standards compared to interval stimulation. We observed no interaction effects of stimulation duration on the target-related P300. While our findings align with previous research, further investigation is warranted to fully elucidate the influence of taVNS on the P300 component and its potential utility as a reliable marker for neuromodulation in this field.

The time course of semantic ambiguity in visual word recognition: behavioral and ERP evidence for the lexical-semantic effect.

Homonyms are words with multiple, unrelated meanings that share a single form and pronunciation. These words provide valuable insights into how semantic representation is retrieved and selected independently of orthography and phonology. This study aims to investigate the temporal dynamics of lexical and semantic processing in the visual recognition of Korean words. Specifically, we examine how homonyms and unambiguous words are processed differently during a lexical decision task (LDT) with EEG recording, considering the effects of word frequency and the number of meanings (NOMs). Participants performed a lexical decision task where they were required to determine if a visually presented stimulus was a valid Korean word. We compared the behavioral responses and event-related potentials (ERPs) evoked by homonyms and unambiguous words, each possessing either high or low word frequency. Both subjective and objective NOMs were measured and manipulated, while controlling for the subjective balance of individual frequencies of meanings to control for confounding from the relatedness of meaning (ROM). For ERP analysis, a non-parametric cluster-based permutation test was employed in addition to the two time windows of interest (i.e., N400 and P600). Behavioral results indicated a marginally significant interaction between word frequency and semantic ambiguity along with a main effect of word frequency, showing faster and more accurate responses for high-frequency words. An ambiguity advantage was observed only for low-frequency words, with no significant effect found for high-frequency words. ERP results revealed that lexical-semantic interactions were reflected in the modulations of the N400 and P600 components. High-frequency homonyms elicited an enhanced N400 amplitude, while low-frequency homonyms showed a reduced P600 amplitude. The findings suggest that the activation of semantic information occurs simultaneously with lexical processing, rather than during post-lexical or decision-making processes. Furthermore, considering balanced homonyms were employed in this study, inhibitory competition may arise from the high-frequency individual meanings of high-frequency words. In contrast, in low-frequency words, a facilitative effect may arise from gains in global semantic activation or semantic feedback to the orthographic level.

What Chemsex does to the brain - neural correlates (ERP) regarding decision making, impulsivity and hypersexuality.

Chemsex describes the use of specific substances (methamphetamine, GHB/GBL, mephedrone, ketamine) which initiate or enhance sexual experiences and is mainly prevalent among men who have sex with men. Many Chemsex users experience somatic complications (for example sexually transmitted diseases) and sometimes adverse sociological, psychological, and neurological symptoms, such as depression, impulse control disorders or hypersexuality. Changes in impulsivity and deficits in executive functions have demonstrated to be associated with addiction and impulse control disorders as well as frontal brain dysfunction and behavioral control deficits. This study aims to explore the effects of neurophysiological correlates of inhibition and decision making in Chemsex users with an EEG paradigm using event-related potentials (N2, P3). 15 Chemsex users and 14 matched control subjects, all of them men who have sex with man, participated in an auditory Go/NoGo/Voluntary Selection EEG paradigm. In addition, clinical data (e.g. regarding depression), demographic information as well as measures of well-being and sexual behavior were collected. The results demonstrated that clinical symptoms, hypersexuality, and sexual risk behavior were more pronounced in Chemsex users compared to non-users. P3 amplitudes did not differ significantly between groups. However, the Chemsex users showed decreased electrophysiological N2 responses in fronto-central brain regions during decision-making, indicating compromised executive function and inhibitory control. The observed impairments may lead to increased risk behavior regarding drug abuse and hypersexuality. Understanding the neurobiological mechanisms can contribute to targeted interventions in order to mitigate the negative consequences of engaging in Chemsex and improve general well-being.

Efficacy of repetitive transcranial magnetic stimulation on post-stroke cognitive impairment: A systematic and a network meta-analysis.

This study aimed to evaluate the efficacy of different repetitive transcranial magnetic stimulation (rTMS) modes in stroke patients with cognitive impairment, and to rank the best option according to the outcome measures. Literature was searched in PubMed, Cochrane Library, Web of Science, Embase, SinoMed, China National Knowledge Infrastructure, Wanfang Database, and VIP Database, from database inception to September 2023. We included randomized controlled trials (RCTs) investigating the efficacy of all rTMS modes for post-stroke cognitive impairment. The selected studies assessed at least one of the following outcome measures: Montreal Cognitive Assessment (MoCA), Mini-Mental State Examination (MMSE), P300 latency and amplitude, and modified Barthel Index (MBI) or BI. Two researchers independently conducted data extraction. Quality assessment was performed using RevMan 5.3 software based on the Cochrane Collaboration's tool, and statistical analysis was conducted by GeMTC 0.14.3 software and Stata 17.0 software. The network meta-analysis included 74 RCTs with a total of 5478 patients. The best probability ranking indicated that intermittent theta burst stimulation (iTBS) was the most effective in enhancing MoCA, MMSE and MBI scores (85%, 54%, 42%, respectively), followed by 10HzrTMS (79%, 50%, 39%, respectively), for P300 amplitude, ≤1HzrTMS was ranked first (52%). The current limited evidence suggests that iTBS may be the optimal approach for improving cognitive and daily life abilities of stroke patients, followed by 10HzrTMS, ≤1HzrTMS may be the preferred option for enhancing P300 amplitude. PROSPERO 2023 CRD42023424771 available from: https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=424771.

The neurological effects of acute physical exhaustion on inhibitory function

ObjectiveWe aimed to investigate the neural mechanisms underlying the inhibitory function performance of maritime Search and Rescue (SAR) personnel in states of physical exhaustion. BackgroundSAR missions pose serious challenges to the cognitive function of SAR personnel, especially in extreme environments and physical exhaustion. It is important to understand SAR personnel's cognitive performance and neural activity under exhaustion to improve the efficiency of task execution and ensure work safety. MethodTwenty-six maritime SAR personnel were recruited to simulate boat operations until they reached a self-imposed state of exhaustion. The exhaustion state was monitored by maximum heart rate and subjective fatigue scale. Two event-related potentials, N200 and P300, were measured during a Go-Nogo task before and after a session of acute exhaustive tasks. ResultsAfter exhaustion, a marked reduction in accuracy, a notable increase in N200 amplitude, and a substantial decline in P300 amplitude under the Nogo condition were observed compared to the baseline phase. Pre- and post-exhaustion comparisons using standardized low-resolution brain electromagnetic tomography revealed reduced activations in the right middle temporal gyrus's N200 component after exhaustion in SAR personnel during the Nogo condition. ConclusionThe results suggest that acute physical exhaustion significantly impacts the inhibition ability of SAR personnel, prolonging the conflict monitoring phase and weakening the response inhibition phase. These findings provide valuable insights into how physical exhaustion affects cognitive functions critical to the safety and effectiveness of SAR operations, and can inform strategies to improve training and equipment to enhance performance under extreme conditions.

Effects of attentional deployment training for relieving negative emotion in individuals with subthreshold depression

ObjectiveAs a prodromal stage to major depressive disorder (MDD), subthreshold depression (StD) has a higher prevalence in the population, resulting in a greater healthcare burden. StD individuals’ current negative emotion could be moderated by attentional deployment. However, it remains unclear whether attentional deployment training can mitigate subsequent negative emotion in StD individuals. MethodsBased on 160 participants, we combined decision task (Experiment 1, N = 69), eye-tracking (Experiment 2, N = 40), and EEG (Experiment 3, N = 51) techniques to investigate how one-week attentional deployment (gain-focus, GF) training modulated the emotional processing of negative stimulus and its underlying neural correlates in StD individuals. ResultsAfter one-week GF training, StD individuals significantly reduced the first fixation time and total fixation time on the negative part (missed opportunities) of decision outcome and showed a decrease in emotional sensitivity to missed opportunities. An increase in N1 and decrease in P3 and LPP (late positive potentials) amplitudes, as well as a decrease in alpha oscillation, were observed when StD individuals faced missed opportunities after training. Additionally, the extent of reduction in StD individuals’ emotional sensitivity to missed opportunities could be significantly predicted by the degree of decrease in alpha oscillation. ConclusionOne-week attentional deployment training could modulate negative emotion in StD individuals and the degree of change in alpha oscillation might act as an objective indicator for the effectiveness of training. SignificanceOur study provides a convenient and effective approach to alleviate the negative emotion of StD individuals.

Hyperacusis questionnaire and event-related potential correlation in migraine patients

This study aims to investigate auditory hypersensitivity and cortical function in migraine patients using the Hyperacusis Questionnaire and the Event-Related Potential (ERP) technique. The study analyzes alterations in the latency and amplitude of the event-related potentials MMN and P300 components. The findings contribute to a better understanding of the physiological relationship between migraine and auditory hypersensitivity. Seventeen migraine patients were admitted to the outpatient clinic of the Department of Otorhinolaryngology-Head and Neck Surgery at Peking University People’s Hospital from June 2023 to September 2023. Nineteen matched healthy subjects were also selected. All participants underwent the pure tone audiometry and the auditory brainstem response test to determine hearing thresholds, the Hyperacusis Questionnaire, the Tinnitus Handicap Inventory, and an ERP examination. The Oddball classical paradigm was used as the stimulation task, and electroencephalography signals were recorded synchronously. The scores of the Hyperacusis Questionnaire, latency and amplitude of MMN and P300 component were compared between the migraine group and the control group, and their correlation was analyzed. The latency of MMN at the Fz and Cz sites in migraine patients was significantly shorter than that in the control group (P < 0.05), and the amplitudes were significantly higher than those in the control group (P < 0.05). The variances in latency and amplitude of P300 at Cz and Pz sites in migraine patients were not statistically significant when compared with the control group. (P > 0.05). The Hyperacusis Questionnaire was negatively correlated with MMN latency, with a correlation coefficient of − 0.374 (P = 0.025), and positively correlated with MMN amplitude, with a correlation coefficient of 0.378 (P = 0.023). There was no significant similarity between the Hyperacusis Questionnaire and P300 latency and amplitude (P > 0.05). Overall, auditory hypersensitivity was enhanced in individuals with migraines compared to healthy individuals, leading to faster information processing, while there may be less impairment in cognitive function.

Effects of peer victimization on cortical processing of social-evaluative stress in patients with major depressive disorder.

Peer victimization contributes to the development of major depressive disorders (MDDs). While previous studies reported differentiated peripheral physiological responses in peer-victimized individuals with depression, little is known about potential alterations of cortical event-related potentials (ERPs) in response to social stimuli in depressive patients with a history of peer victimization. Using a social condition paradigm, the present study examined whether peer victimization alters conditioned cortical responses to potentially threatening social stimuli in MDD patients and healthy controls. In the task, we studied ERPs to conditioned stimuli (CSs), i.e. still images of faces, that were coupled to unconditioned socially negative and neutral evaluative video statements. Peer victimization was related to more pronounced P100 amplitudes in reaction to negative and neutral CSs. Attenuated P200 amplitudes in peer-victimized individuals were found in response to negative CSs. Cortical responses to CSs were not influenced by a diagnosis of MDD. The results suggest altered responsiveness to interpersonal information in peer-victimized individuals. Facilitated early processing of social threat indicators may prevent peer-victimized individuals from adaptive responses to social cues, increasing their vulnerability for depression.

Recording the tactile P300 with the cEEGrid for potential use in a brain-computer interface.

Brain-computer interfaces (BCIs) are scientifically well established, but they rarely arrive in the daily lives of potential end-users. This could be in part because electroencephalography (EEG), a prevalent method to acquire brain activity for BCI operation, is considered too impractical to be applied in daily life of end-users with physical impairment as an assistive device. Hence, miniaturized EEG systems such as the cEEGrid have been developed. While they promise to be a step toward bridging the gap between BCI development, lab demonstrations, and home use, they still require further validation. Encouragingly, the cEEGrid has already demonstrated its ability to record visually and auditorily evoked event-related potentials (ERP), which are important as input signal for many BCIs. With this study, we aimed at evaluating the cEEGrid in the context of a BCI based on tactually evoked ERPs. To compare the cEEGrid with a conventional scalp EEG, we recorded brain activity with both systems simultaneously. Forty healthy participants were recruited to perform a P300 oddball task based on vibrotactile stimulation at four different positions. This tactile paradigm has been shown to be feasible for BCI repeatedly but has never been tested with the cEEGrid. We found distinct P300 deflections in the cEEGrid data, particularly at vertical bipolar channels. With an average of 63%, the cEEGrid classification accuracy was significantly above the chance level (25%) but significantly lower than the 81% reached with the EEG cap. Likewise, the P300 amplitude was significantly lower (cEEGrid R2-R7: 1.87 μV, Cap Cz: 3.53 μV). These results indicate that a tactile BCI using the cEEGrid could potentially be operated, albeit with lower efficiency. Additionally, participants' somatosensory sensitivity was assessed, but no correlation to the accuracy of either EEG system was shown. Our research contributes to the growing amount of literature comparing the cEEGrid to conventional EEG systems and provides first evidence that the tactile P300 can be recorded behind the ear. A BCI based on a thus simplified EEG system might be more readily accepted by potential end-users, provided the accuracy can be substantially increased, e.g., by training and improved classification.

Does Transcranial Direct Current Stimulation Affect Potential P300-Related Events in Vascular Dementia? Considerations from a Pilot Study.

Vascular dementia, the second most common type of dementia, currently lacks a definitive cure. In the pursuit of therapies aimed at slowing its progression and alleviating symptoms, transcranial direct current stimulation (tDCS) emerges as a promising approach, characterized by its non-invasive nature and the ability to promote brain plasticity. In this study, the primary objective was to investigate the effects of a two-week cycle of tDCS on the dorsolateral prefrontal cortex (DLPFC) and neurophysiological functioning in thirty patients diagnosed with vascular dementia. Each participant was assigned to one of two groups: the experimental group, which received anodal tDCS to stimulate DPCFL, and the control group, which received sham tDCS. Neurophysiological functions were assessed before and after tDCS using P300 event-related potentials (ERPs), while neuropsychological function was evaluated through a Mini-Mental State Examination (MMSE). The results showed a reduction in P300 latency, indicating a faster cognitive process; an increase in P300 amplitude, suggesting a stronger neural response to cognitive stimuli; and a significant improvement in MMSE scores compared to the control group, indicating an overall enhancement in cognitive functions. These findings suggest that tDCS could represent a promising therapeutic option for improving both neurophysiological and cognitive aspects in patients with vascular dementia.

Spatial distribution of parameters of auditory cognitive evoked potentials P300 in young adults with myopia

BACKGROUND: Myopia typically presents itself between the ages of 18 and 29, affecting both women (35%) and men (59.9%). The prevalence of impaired accommodation and refraction in modern individuals can be attributed to the increased strain on visual sensory systems resulting from the widespread digitalization of various aspects of human life. This increased strain poses a potential risk for alterations in cortical processes related to perception and information processing, increasing the risk of cognitive impairment. AIMS: To study the differences in the characteristics of evoked potentials P300 in 21–23 years old individuals with myopia compared to those without ophthalmic pathology. MATERIAL AND METHODS: An ophthalmological examination was conducted on a group of young individuals aged 21–23 years (average age 22.3±0.1 years) residing in the city of Arkhangelsk. The participants were university students, totaling 54 individuals of both genders (34 females and 20 males). During the examination, uncorrected visual acuity, best-corrected visual acuity, and clinical refraction value (in diopters) were assessed for each participant, along with qualitative changes. Additionally, the reserve of relative accommodation (in diopters) was estimated based on the results of the accommodation study. The study sample consisted of 32 participants without ophthalmic pathology and 22 individuals diagnosed with myopia. The parameters of cognitive evoked auditory potential P300 were measured using an electroencephalograph «NeuronSpectrum- 4/VPM» (Neurosoft, Russia) in both groups. The data were analyzed using the SPSS statistical software package. RESULTS: Students with myopia had longer decision-making times compared to individuals with normal vision, as indicated by auditory evoked potentials P300. This effect was observed in the temporal, mid-frontal, and left frontal regions of the brain. Additionally, the anterior-occipital gradient of P300 amplitude was attenuated, with a high amplitude P300 in the left occipital region. CONCLUSION: Assessment of myopia should be complemented with an examination of the functional status of the cerebral cortex. Extended auditory processing time, activation of both hemispheres and involvement of the occipital regions during the processing of auditory information may be a result of functional reorganization of the cerebral cortex in individuals with myopia.