N100 Amplitude Research Articles

Relationships between clinical symptoms, cognitive functioning, and TMS-evoked potential features in patients with major depressive disorder.

Cognitive impairment is a common clinical symptom of patients with major depressive disorder (MDD). Transcranial magnetic stimulation-evoked potentials (TEPs) detect cortical excitability and connectivity and provide potential biomarkers for MDD patients and their cognitive impairment. This study aimed to investigate the interrelationships between clinical symptoms, cognitive function, and electrophysiological marker TEPs in patients with MDD. A total of 117 participants were recruited, including 59 MDD patients and 58 healthy controls. Clinical symptoms were assessed by the Hamilton Depression Rating Scale and Hamilton Anxiety Rating Scale, and cognitive functioning was assessed by the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). TEPs were recorded by transcranial magnetic stimulation combined with electroencephalography (TMS-EEG). MDD patients exhibited lower RBANS total (P < 0.001), immediate memory (P = 0.001), language (P = 0.003), attention (P < 0.001), and delayed memory (P = 0.008) scores than HCs. Patients with MDD had larger amplitudes for N100 (P = 0.040) and N280 (P = 0.037), compared to HCs. Correlation analysis indicated significant correlations between the following RBANS scores and TEPs: language and N45 amplitude (r = 0.222, P = 0.024), language and P60 amplitude (r = 0.278, P = 0.004), attention and P180 amplitude (r = 0.213, P = 0.030), RBANS total score and P30 amplitude (r = 0.198, P = 0.044), visuospatial/constructional index and N100 amplitude (r = -0.272, P = 0.005). The results of this study indicate that cortical dysfunction and cognitive impairment are present in patients with MDD and that there is a strong correlation between them, suggesting that TEPs detected by the TMS-EEG may be used as a biomarker for MDD patients and their cognitive impairment.

Effects of a Functional Cone Mushroom (Termitomyces fuliginosus) Protein Snack Bar on Cognitive Function in Middle Age: A Randomized Double-Blind Placebo-Controlled Trial.

Background: Due to the rising prevalence of cognitive impairment in the middle-aged and elderly population, combined with consumer demand for functional foods to improve health and well-being. Objective: This study aimed to formulate a functional cone mushroom (Termitomyces fuliginosus) (FCM) protein snack bar and evaluate its amino acid profile, phytochemical contents, biological activity and impact on cognitive function. Methods: A total of 26 middle-aged male and female participants were randomized and divided into placebo, FCM1 and FCM2 groups. Continuous consumption was performed for 6 weeks. Demographic data, body composition, cognitive function and memory were evaluated at baseline and at the end of the study period (6 weeks). Results: The event-related potential (ERP) analysis results showed a significant increase in N100 and P300 amplitude at the Fz location in participants who consumed the functional cone mushroom protein snack bar at a dose of 1 g compared to the placebo group (p = 0.015). Additionally, subjects who consumed the functional cone mushroom protein snack bar at a dose of 2 g showed a significantly increased P300 amplitude and percent accuracy of numeric working memory (p = 0.048) compared to those in the placebo group (p = 0.044). The possible underlying mechanism may involve AChE and MAO suppression activity alongside antioxidant activity. Conclusions: These data suggest that FCM can improve cognitive function and memory and may be considered for use in natural supplementation products with possible health benefits.

Face and face pareidolia in patients with temporal lobe epilepsy indicates different neural processing: an event-related potential study

BackgroundVisual perception of face images or face pareidolia can be evaluated with event-related potentials (ERP) for healthy subjects and patients with neurological conditions. In this study, we aimed to analyse event-related potential components such as P100, N100, N170, and vertex-positive potential (VPP) in response to face pareidolia perception in temporal lobe epilepsy (TLE) patients.MethodsERPs were recorded during the pareidolia test. Waveforms were analzyed and current source density (CSD) maps were generated.ResultsCSD profiles were shown to be interpretable when face and face pareidolia conditions. N100, P100, and N170 components showed larger amplitudes and longer latency in epilepsy patients in response to face pareidolia stimuli compared to real face images. However, the N170 component latency did not differ significantly between epilepsy patients and healthy participants, while the larger amplitude and longer latency of N100 and P100 responses were evoked in healthy patients.ConclusionsOur results indicate a difference in the neural mechanisms of processing real face information and pareidolia face-like information in TLE patients.

TMS-induced phase resets depend on TMS intensity and EEG phase

Objective. The phase of the electroencephalographic (EEG) signal predicts performance in motor, somatosensory, and cognitive functions. Studies suggest that brain phase resets align neural oscillations with external stimuli, or couple oscillations across frequency bands and brain regions. Transcranial Magnetic Stimulation (TMS) can cause phase resets noninvasively in the cortex, thus providing the potential to control phase-sensitive cognitive functions. However, the relationship between TMS parameters and phase resetting is not fully understood. This is especially true of TMS intensity, which may be crucial to enabling precise control over the amount of phase resetting that is induced. Additionally, TMS phase resetting may interact with the instantaneous phase of the brain. Understanding these relationships is crucial to the development of more powerful and controllable stimulation protocols.Approach.To test these relationships, we conducted a TMS-EEG study. We applied single-pulse TMS at varying degrees of stimulation intensity to the motor area in an open loop. Offline, we used an autoregressive algorithm to estimate the phase of the intrinsicµ-Alpha rhythm of the motor cortex at the moment each TMS pulse was delivered.Main results. We identified post-stimulation epochs whereµ-Alpha phase resetting and N100 amplitude depend parametrically on TMS intensity and are significantversusperipheral auditory sham stimulation. We observedµ-Alpha phase inversion after stimulations near peaks but not troughs in the endogenousµ-Alpha rhythm.Significance. These data suggest that low-intensity TMS primarily resets existing oscillations, while at higher intensities TMS may activate previously silent neurons, but only when endogenous oscillations are near the peak phase. These data can guide future studies that seek to induce phase resetting, and point to a way to manipulate the phase resetting effect of TMS by varying only the timing of the pulse with respect to ongoing brain activity.

Impaired somatosensory habituation in older adults with chronic pain during an affective oddball task.

Chronic pain is one of the most common health conditions among older adults, triggering various disruptions in information processing across attentional, emotional, and somatosensory domains. However, there is insufficient information about how these aspects interact and their potential contribution to the vulnerability of older adults to chronic pain. This study aimed to investigate potential alterations induced by chronic pain during aging in attentional aspects of tactile stimulation and to observe the influence of affective context. Twenty-six older adults with chronic pain (70.00 ± 5.07 years; 11 males), 28 pain-free older adults (69.57 ± 3.96 years; 13 males) and 27 healthy younger adults (21.48 ± 1.80 years; 14 males) participated in the study. We compared the somatosensory evoked potentials elicited by frequent and deviant stimulation (probability 14%) applied when participants were viewing blocks of pleasant, unpleasant, and neutral images from the International Affective Picture System. During frequent stimulation, older adults with chronic pain showed higher P50 and N100 amplitudes compared to pain-free older adults and younger individuals. Furthermore, the older group with pain exhibited higher P300 amplitude during emotional contexts compared to neutral scenarios. During deviant stimulation, older adults with chronic pain exhibited higher P50 and N100 amplitudes compared to pain-free older adults but displayed typical age-related flattening during P300. These findings indicate that chronic pain leads to a decline in the ability to habituate to non-painful irrelevant somatosensory stimuli, especially when it is presented in an emotional context. In the present study, we have observed how older individuals suffering from chronic pain exhibit a decline in the habituation capacity of irrelevant somatosensory information. Furthermore, we have observed how the affective context in which these individuals are situated leads to an exacerbation of this deficit. Enhancing our comprehension of how aging and chronic pain interact to impact somatosensory processing could facilitate the tailoring of novel intervention strategies.

Mixed martial arts athletes demonstrate different brain vital sign profiles compared to matched controls at baseline.

We investigated objective brain vital signs derived from event-related potentials (ERPs) for mixed martial arts (MMA) athletes and matched controls (N = 24). Brain vital sign scans were acquired from 9 MMA athletes and 15 age-and sex-matched controls. Our analysis specifically compared differences in brain vital signs between MMA athletes and controls at baseline. We predicted that MMA athletes would show significant differences relative to controls due to their ongoing exposure to repetitive head impacts. Participants were scanned to extract three well-established ERPs: N100 for auditory sensation; P300 for basic attention; and N400 for cognitive processing. Scans were verified using automated reports, with N100, P300, and N400 amplitudes and latencies manually identified by a blinded reviewer. Brain vital signs were compared across groups with a Kruskal-Wallis H-test for independent samples, with FDR correction for multiple comparisons. We identified significant differences between MMA athletes and controls. Specifically, there were significant N400 amplitude reductions, indicating that exposure to repetitive head impacts in MMA may be associated with changes in brain function.

Differential analgesic effects of high-frequency or accelerated intermittent theta burst stimulation of M1 on experimental tonic pain: Correlations with cortical activity changes assessed by TMS-EEG

Accelerated intermittent theta burst stimulation (AiTBS) has attracted much attention in the past few years as a new form of brain stimulation paradigm. However, it is unclear the relative efficacy of AiTBS on cortical excitability compared to conventional high-frequency rTMS. Using concurrent TMS and electroencephalogram (TMS-EEG), this study systematically compared the efficacy on cortical excitability and a typical clinical application (i.e. pain), between AiTBS with different intersession interval (ISIs) and 10-Hz rTMS. Participants received 10-Hz rTMS, AiTBS-15 (3 iTBS sessions with a 15-min ISI), AiTBS-50 (3 iTBS sessions with a 50-min ISI), or Sham stimulation over the primary motor cortex on four separate days. All four protocols included a total of 1800 pulses but with different session durations (10-Hz rTMS ​= ​18, AiTBS-15 ​= ​40, and AiTBS-50 ​= ​110 ​min). AiTBS-50 and 10-Hz rTMS were more effective in pain reduction compared to AiTBS-15. Using single-pulse TMS-induced oscillation, our data revealed low gamma oscillation as a shared cortical excitability change across all three active rTMS protocols but demonstrated completely opposite directions. Changes in low gamma oscillation were further associated with changes in pain perception across the three active conditions. In contrast, a distinct pattern of TMS-evoked potentials (TEPs) was revealed, with 10-Hz rTMS decreasing inhibitory N100 amplitude and AiTBS-15 reducing excitatory P60 amplitude. These changes in TEPs were also covarying with low gamma power changes. Sham stimulation indicated no significant effect on either cortical excitability or pain perception. These results are relevant only for provoked experimental pain, without being predictive for chronic pain, and revealed a change in low gamma oscillation, particularly around the very particular frequency of 40 ​Hz, shared between AiTBS and high-frequency rTMS. Conversely, cortical excitability (balance between excitation and inhibition) assessed by TEP recording was modulated differently by AiTBS and high-frequency rTMS paradigms.

Cognition in Patients with Spinocerebellar Ataxia 1 (SCA1) and 2 (SCA2): A Neurophysiological and Neuropsychological Approach.

Background/Objectives: Cognitive impairment in spinocerebellar ataxia patients has been reported since the early-disease stage. We aimed to assess cognitive differences in SCA1 and SCA2 patients. Methods: We performed neuropsychological (NPS) and neurophysiological (auditory event-related potentials, aERPs) assessments in 16 SCA1 and 18 SCA2 consecutive patients. Furthermore, clinical information (age at onset, disease duration, motor disability) was collected. Results: NPS tests yielded scores in the normal range in both groups but with lower scores in the Frontal Assessment Battery (p < 0.05) and Visual Analogue Test for Anosognosia for motor impairment (p < 0.05) in SCA1, and the Trail Making Test (p < 0.01), Raven's progressive matrices (p < 0.01), Stroop (p < 0.05), and emotion attribution tests (p < 0.05) in SCA2. aERPs showed lower N100 amplitude (p < 0.01) and prolonged N200 latency (p < 0.01) in SCA1 compared with SCA2. Clinically, SCA2 had more severe motor disability than SCA1 in the Assessment and Rating of Ataxia Scale. Conclusions: SCA2 showed more significant difficulties in attentional, visuospatial, and emotional function, and greater motor impairment. In contrast, SCA1 showed less cognitive flexibility/phasic ability, probably affected by a more severe degree of dysarthria. The same group revealed less neural activity during nonconscious attentional processing (N100-N200 data), suggesting greater involvement of sensory pathways in discriminating auditory stimuli. NFS did not correlate with NPS findings, implying an independent relationship. However, the specific role of the cerebellum and cerebellar symptoms in NPS test results deserves more focus.

The impact of virtual reality and distractors on attentional processes: insights from EEG.

Virtual reality (VR) allows to create controlled scenarios in which the quantity of stimuli can be modulated, as happen in real-life, where humans are subjected to various multisensory-often overlapping-stimuli. The present research aimed to study changes in attentional processes within an auditory oddball paradigm during a virtual exploration, while varying the amount of distractors. Twenty healthy volunteers underwent electroencephalography (EEG) during three different experimental conditions: an auditory oddball without VR (No-VR condition), an auditory oddball during VR exploration without distractors (VR-Empty condition), and an auditory oddball during VR exploration with a high level of distractors (VR-Full condition). Event-related potentials (ERPs) were computed averaging epochs of EEGs and analyzing peaks at 100ms (N100) and 300ms (P300) latencies. Results showed modulation of N100 amplitude in Fz and of P300 amplitude in Pz. Statistically significant differences in latency were observed only for P300 where the latency results delayed from the No-VR to VR-Full. The scalp topography revealed for P100 no significant differences between frequent and rare stimuli in either the No-VR and VR-Empty conditions. However, significant results were found in N100 in VR-Full condition. For P300, results showed differences between frequent and rare stimuli, in every condition. However, this difference is gradually less widespread from No-VR condition to the VR-Full. The emerging integration of VR with EEG may have important implications for studying brain attentional processing.

My choice, my actions: self-determination, not instrumental value of outcomes enhances outcome monitoring during learning.

Freedom of choice enhances our sense of agency. During goal-directed behavior, the freedom to choose between different response options increases the neural processing of positive and negative feedback, indicating enhanced outcome monitoring under conditions of high agency experience. However, it is unclear whether this enhancement is predominantly driven by an increased salience of self- compared to externally determined action outcomes or whether differences in the perceived instrumental value of outcomes contribute to outcome monitoring in goal-directed tasks. To test this, we recorded electroencephalography while participants performed a reinforcement learning task involving free choices, action-relevant forced choices, and action-irrelevant forced choices. We observed larger midfrontal theta power and N100 amplitudes for feedback following free choices compared with action-relevant and action-irrelevant forced choices. In addition, a Reward Positivity was only present for free but not forced choice outcomes. Crucially, our results indicate that enhanced outcome processing is not driven by the relevance of outcomes for future actions but rather stems from the association of outcomes with recent self-determined choice. Our findings highlight the pivotal role of self-determination in tracking the consequences of our actions and contribute to an understanding of the cognitive processes underlying the choice-induced facilitation in outcome monitoring.

N100 as a response prediction biomarker for accelerated 1 Hz right DLPFC-rTMS in major depression

Background and objectiveRepetitive transcranial magnetic stimulation (rTMS) is a safe and effective treatment for major depressive disorder (MDD); however, this treatment currently lacks reliable biomarkers of treatment response. TMS-evoked potentials (TEPs), measured using TMS-electroencephalography (TMS-EEG), have been suggested as potential biomarker candidates, with the N100 peak being one of the most promising. This study investigated the association between baseline N100 amplitude and 1 Hz right dorsolateral prefrontal cortex (R-DLPFC) accelerated rTMS (arTMS) treatment in MDD. MethodsBaseline TMS-EEG sessions were performed for 23 MDD patients. All patients then underwent 40 sessions of 1 Hz R-DLPFC (F4) arTMS over 5 days and a follow-up TMS-EEG session one week after the end of theses arTMS sessions. ResultsBaseline N100 amplitude at F4 showed a strong positive association (p < .001) with treatment outcome. The association between the change in N100 amplitude (baseline to follow-up) and treatment outcome did not remain significant after Bonferroni correction (p = .06, corrected; p = .03, uncorrected). Furthermore, treatment responders had a significantly larger mean baseline F4 TEP amplitude during the N100 time frame compared to non-responders (p < .001). Topographically, after Bonferroni correction, F4 is the only electrode at which its baseline N100 amplitude showed a significant positive association (p < .001) with treatment outcome. LimitationsLack of control group and auditory masking. ConclusionBaseline N100 amplitude showed a strong association with treatment outcome and thus demonstrated great potential to be utilized as a cost-effective and widely adoptable biomarker of rTMS treatment in MDD.

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.

Abnormal Global Cortical Responses in Drug-Naïve Patients With Schizophrenia Following Orbitofrontal Cortex Stimulation: A Concurrent Transcranial Magnetic Stimulation–Electroencephalography Study

BackgroundAbnormalities in cortical excitability and plasticity have been considered to underlie the pathophysiology of schizophrenia. Transcranial magnetic stimulation combined with electroencephalography (TMS-EEG) can provide a direct evaluation of cortical responses to TMS. Here, we employed TMS-EEG to investigate cortical responses to orbitofrontal cortex (OFC) stimulation in schizophrenia. MethodsIn total, we recruited 92 drug-naïve patients with first-episode schizophrenia and 51 age- and sex-matched healthy individuals. For each participant, one session of 1-Hz repetitive TMS (rTMS) was delivered to the right OFC, and TMS-EEG data were obtained to explore the change in cortical-evoked activities before and immediately after rTMS during the eyes-closed state. The MATRICS Consensus Cognitive Battery was used to assess neurocognitive performance. ResultsThe cortical responses indexed by global mean field amplitudes (i.e., P30, N45, and P60) were larger in patients with schizophrenia than in healthy control participants at baseline. Furthermore, after one session of 1-Hz rTMS over the right OFC, the N100 amplitude was significantly reduced in the healthy control group but not in the schizophrenia group. In the healthy control participants, there was a significant correlation between modulation of P60 amplitude by rTMS and working memory; however, this correlation was absent in patients with schizophrenia. ConclusionsAberrant global cortical responses following right OFC stimulation were found in patients with drug-naïve first-episode schizophrenia, supporting its significance in the primary pathophysiology of schizophrenia.

Investigation of fabric tactile perception using the event-related potential method

The mechanism of the neuro-electrophysiological response of the human brain to skin tactile stimulation has always been an important research topic in the field of comfort perception of textile materials. In order to explore the characteristic neural potential components induced by various fabric tactile stimulation and their influence rules, event-related potential technology with ultra-high time resolution was introduced to monitor the somatosensory brain region under tactile stimulation of fabrics with different tactile properties, and the signal changes of related potentials were extracted and analyzed. The results showed that the amplitudes of N100 increased with the stiffness of the fabric, the amplitudes of P200 decreased with the smoothness of the fabric, and the amplitudes of P300 decreased with the smoothness and softness of the fabric. These results indicated that N100, P200, and P300 potentials could be used as neurophysiological response indexes of brain neurons to distinguish the subtle differences in fabric tactile properties. This finding not only laid a scientific theoretical basis for the brain perception mechanism of fabric tactile properties, but also provided a possibility for further quantification characterization of textile comfort perception.

Electrophysiological indexes of ingroup bias in a group Stroop task: Evidence from an event-related potential study

Although cognitive system assigns higher attentional resources to ingroup information than outgroup information, but it is unclear whether the ingroup bias can be measured by the processes that are related to allocation of attentional resources to ingroup information. Thus, a group Stroop task was developed to study the issues combining with event-related potential (ERP) technique in this study. Specifically, 34 subjects (17 female, mean age = 20.76 ± 1.26) were firstly divided into blue or red group (17 subjects for each group); then they were asked to categorize four words of Stroop task into “our team” or “other team” based on the ink color (blue/red) of the words whose meaning were also red/blue. The behavioral results showed that outgroup ink color processing was interfered by ingroup word meaning, but the ingroup ink color processing was less/not interfered by outgroup word meaning. The ERP results showed that the amplitude of frontal N100 was enhanced when more attentional resources were automatically captured by ingroup information in early stage than outgroup information; P2/N2 amplitude was reduced or enhanced when outgroup information processing was interfered by ingroup information; enhanced P3b amplitude reflected that attention could be more easily allocated to ingroup information than outgroup information based on target. This study implied a novel direction to study the neural basis of ingroup bias by investigating the roles of ingroup bias in assigning attentional resources to group information.

Preliminary observations on the associations between sensory processing abnormalities and event-related potentials in adults with autism spectrum disorder.

Autism spectrum disorder (ASD) is a neurodevelopmental disorder that is thought to involve a variety of neurophysiological characteristics. Event-related potentials (ERPs) reflect cognitive functions in the brain's cognitive processing. In this study, we investigated differences in P300 and N100 of ERPs between ASD and typically developing groups and focused on the relationship between the components of ERPs and measures of autistic traits and sensory processing characteristics. ERPs were measured in 96 subjects in the ASD group and 62 subjects in the age- and sex-adjusted typically developing group. Correlations between each component and the scores of the Autism-Spectrum Quotient Japanese version (AQ-J) and the Adolescent and Adult Sensory Profile (AASP) were also evaluated. The ASD group showed a significant decrease in the amplitude of N100 at C3. Furthermore, a negative correlation was found between lower amplitude at C3 of N100 and low registered sensory scores in both groups. Our findings imply that the N100 amplitude at C3 could be a potential indicator for examining the neurophysiological traits of ASD; however, these results should be interpreted with caution due to their preliminary nature. These tentative insights into sensory processing anomalies may be discernible in specific subsets of the ASD population, providing a foundation for future investigative pathways.

How tie strength influences purchasing intention in social recommendation: evidence from behavioral model and brain activity

PurposeSocial recommendation has been recognized as a kind of e-commerce with large potential, but how social recommendations influence consumer decisions is still unclear. This paper aims to investigate how recommendations from different social ties influence consumers’ purchase intentions through both behavior and brain activity.Design/methodology/approachUtilizing behavioral (N = 70) and electroencephalogram (EEG) (N = 49) experiments, this study explored participants’ behavior and brain responses after being recommended by different social ties. The data were analyzed using statistical inference and event-related potential (ERP) analysis.FindingsBehavioral results show that social tie strength positively impacts purchase intention, which can be fitted by a logarithmic model. Moreover, recommender-to-customer similarity and product affect mediate the effect of tie strength on purchase intention serially. EEG findings show that recommendations from weak tie strength elicit larger N100, N200 and P300 amplitudes than those from strong tie strength. These results imply that weak tie strength may motivate individuals to recruit more mental resources in social recommendation, including unconscious processing of consumer attention and conscious processing of cognitive conflict and negative emotion.Originality/valueThis study considers the effects of continuous social ties on purchase intention and models them mathematically, exploring the intrinsic mechanisms by which strong and weak ties influence purchase intentions through recommender-to-customer similarity and product affect, contributing to the applications of the stimulus-organism-response (SOR) model in the field of social recommendation. Furthermore, our study adopting EEG techniques bridges the gap of relying solely on self-report by providing an avenue to obtain relatively objective findings about the consumers’ early-occurred (unconscious) attentional responses and late-occurred (conscious) cognitive and emotional responses in purchase decisions.

Dynamic Sleep Architecture Revealed: Sleep Auditory Evoked Potentials from N100 to P900

Background: The research landscape in sleep is currently shifting toward minute changes in brain functioning during different stages. This fine approach necessitates a dynamic assessment as in the case of electrophysiology. The present study aimed to investigate brain responsiveness during different stages and times of nocturnal sleep using auditory evoked potentials (AEPs). Materials and Methods: Sleep recordings of 18 volunteer subjects were analyzed. During sleep recordings, auditory stimuli were presented in the ear channels. Sleep stages were scored according to the American Academy of Sleep Medicine system. AEPs were analyzed in nonrapid eye movement sleep stages. Alterations of N100, P200, N300, P450, N550, and P900 waveforms were investigated in the first and second halves of sleep duration. Results: N100 amplitude was higher in light sleep, both in the first and the second halves of the night (sleep duration). The amplitude of P900 was higher in the deep sleep stage in both halves. Significant amplitude reductions were found in N100, P200, P450, and P900 in the second half of the sleep. Conclusions: The changes found suggest that they are related to the dynamics of sensory processing to maintain functional sleep. The findings of the present study emphasize that in the course of sleep, both the proportions of sleep stages and the microarchitecture within the stages alter between the first and second halves of sleep.

Neural Process of Emotional Valence Quality in Extraversion: Localisation, Components and Specific Electrodes Analyses

The process of emotion is greatly influenced by people’s personalities. This study aimed to determine the interaction between extraversion continuum (extravert, ambivert, and introvert) and the process of emotion from different valence quality of visual stimuli (high, moderate, low). Potential participants had their extraversion trait screened using the Extraversion-Five-Factor Nonverbal Personality Questionnaire (E-FF-NPQ). Ninety participants (30 for each group of personality) enrolled in this study. In the Event-Related Potential (ERP) session, participants’ emotion was evoked by a series of pictures (visual stimuli) from the International Affective Picture System (IAPS) with different valence qualities (high, moderate, low). No significant interaction between extraversion continuum and valence quality was observed at component level of analysis. However, several specific electrodes revealed significant interaction – P3 latency (p=0.03) and F8 amplitude (p=0,02) of N200 and Cz latency of P300 (p=0.02). Low-resolution brain electromagnetic tomography (sLORETA) revealed almost similar pattern of N200 and P300 localisation in the high valence state, particularly among extraverts. At the very least, a minor difference between extravert and non-extravert could be expected with careful consideration of cultural and methodological bias.

Animacy Processing in Autism: Event-Related Potentials Reflect Social Functioning Skills.

Though previous studies with autistic individuals have provided behavioral evidence of animacy perception difficulties, the spatio-temporal dynamics of animacy processing in autism remain underexplored. This study investigated how animacy is neurally encoded in autistic adults, and whether potential deficits in animacy processing have cascading deleterious effects on their social functioning skills. We employed a picture naming paradigm that recorded accuracy and response latencies to animate and inanimate pictures in young autistic adults and age- and IQ-matched healthy individuals, while also employing high-density EEG analysis to map the spatio-temporal dynamics of animacy processing. Participants' social skills were also assessed through a social comprehension task. The autistic adults exhibited lower accuracy than controls on the animate pictures of the task and also exhibited altered brain responses, including larger and smaller N100 amplitudes than controls on inanimate and animate stimuli, respectively. At late stages of processing, there were shorter slow negative wave latencies for the autistic group as compared to controls for the animate trials only. The autistic individuals' altered brain responses negatively correlated with their social difficulties. The results suggest deficits in brain responses to animacy in the autistic group, which were related to the individuals' social functioning skills.