Sensory Interaction and Balancing Ability Evaluation of the Elderly Using a Simplified Force Plate System.

The Wii balance board (WBB) is a simplified force plate system used to evaluate the balancing ability of the elderly via a sensory interaction task to confirm a significant standing balance index. The accuracy of this system has been verified in previous studies. In this study, an instrumented and modified clinical test of sensory interaction on balance (i-mCTSIB) was performed on 84 elderly subjects, and the variables for center of pressure (CoP) were calculated using WBB for each task condition. The results indicate that the visual condition has a significant effect on the sway proprioceptive sensory variables with a foam condition as their complexity increases. In addition, the correlation between the variable and Berg Balance Scale was not confirmed since CTSIB is a sensory interaction on balance ability. Therefore, WBB can be used to evaluate balancing ability based on sensory interactions consisting of the surface condition.

Unusual solvent-dependent photophysical and self-assembly properties of NO2 substituted T-shaped phenazines.

This paper investigates the importance of substituent placement when designing low-molecular mass π-organogelators. The electron-deficient NO2 substituent was systematically added to novel T-shaped phenazines to examine electronic as well as assembly properties. This T-shaped molecular platform promotes selective electronic tuning, which can be theoretically analyzed by examining the system's frontier molecular orbitals. Electronic properties were characterized by UV-vis spectroscopy and cyclic voltammetry, and comparisons were made based on number and placement of the NO2 group. Computational chemistry (B3LYP/6-31G*) was employed for geometry optimizations, and to generate molecular orbital diagrams for all systems. The most noticeable influence of NO2 position was found for two molecules with four NO2 groups placed at different locations about the molecule (T-34dNT and T-35dNT). A 0.13 eV difference in ELUMO was observed while EHOMO was not significantly impacted by this change only in NO2 placement. Interestingly and unexpectedly, the photophysical properties and solvent-dependent gelation properties were considerably different for T-34dNT and T-35dNT. T-34dNT exhibited a unique fluorescence (FL) solvatochromism, with FL intensity and maxima dependent on solvent polarity. This result is indicative of intramolecular charge transfer. In addition, long tailing at the solid-state absorption of T-34dNT suggests the presence of intermolecular charge transfer. The gelation of T-34dNT produced chromism ranging from red to orange to yellow when the solvents changed from acetonitrile to ethyl acetate to cyclohexane, respectively. T-35dNT gels in these solvents did not exhibit any of the same properties. Xerogel morphology characterizations were carried out using three different solvents for both T-34dNT and T-35dNT. In the case of T-34dNT, striking differences in the morphology were detected by field-emission scanning electron microscopy (FE-SEM). We conclude that numbers of substituents are not the only consideration in effective molecular design for organogelators, but that substituent position plays a critical role in certain fundamental properties of these systems.

Controlling the electron-deficiency of self-assembling pyrazine-acenes: a collaborative experimental and theoretical investigation.

This paper reports novel pyrazine-acenes containing electron-deficient heteroaromatic π-extenders, such as pyridine, pyrazine, and benzothiadiazole, directly fused with pyrazine. Electronic properties of these systems were characterized by UV-Vis, fluorescence spectroscopy, and cyclic voltammetry. Computational electronic property evaluation of all experimentally synthesized compounds is provided, and is coupled with electronic calculations of closely related compounds that were not synthetically feasible. Our theoretical results provide insight into the overall analysis and interpretation of the experimentally observed trends. In this study, we found a systematic decrease in the LUMO energy (E(LUMO)) with an increasing number of imine functions in the π-extender. Additionally, when comparing the pyrazine-acene containing pyrazine π-extender to a reference compound with C≡N peripheral substituents, we found that the imine function is comparable to the C≡N substituent in lowering E(LUMO). The most dramatic E(LUMO) lowering was experimentally observed using dibromobenzothiadiazole as a π-extender. In all cases, the HOMO energy (EHOMO) was negligibly affected, thus we found options for electronic property control based solely on E(LUMO) manipulation. This is computationally validated by an examination of the molecular orbitals in which the LUMO orbital was found predominantly on the π-extender section of the molecules, while the HOMO orbital was localized away from the π-extender. Interestingly, the self-assembly of all the experimentally synthesized compounds showed excellent one-dimensional fiber formation in spite of their large π-core framework. These fibers were characterized by atomic force microscopy and UV-Vis spectroscopy.

Recovery time from VR sickness due to susceptibility: Objective and quantitative evaluation using electroencephalography.

With the increasing use of virtual reality (VR) devices, interest in reducing their negative effects, such as VR sickness, is also increasing. This study used electroencephalography (EEG) to investigate participants' VR sickness recovery time after watching a VR video. We tested 40 participants in advance using a motion sickness susceptibility questionnaire (MSSQ). We classified the participants into two groups (sensitive group/non-sensitive group) depending on their MSSQ scores. We used a simulator sickness questionnaire (SSQ) and EEG to evaluate VR sickness. The SSQ score increased significantly after watching the VR sickness-inducing video (VR video) in both groups (p < 0.001). The recovery time based on the SSQ was 11.3 ± 6.6 min for the sensitive group and 9.1 ± 5.2 min for the non-sensitive group. The difference in recovery time between the two groups was not significant (p > 0.05). EEG results showed that recovery time took an average of 11.5 ± 7.1 min in both groups. The EEG data showed that the delta wave increased significantly across all brain areas (p < 0.01). There was no statistical difference between groups in recovering VR sickness depending on individual characteristics. However, we confirmed that subjective and objective VR recovery required at least 11.5 min. This finding can inform recommendations regarding the VR sickness recovery times.

Development and Application of a Stability Index Estimation Algorithm Based on Machine Learning for Elderly Balance Ability Diagnosis in Daily Life.

BACKGROUND: The stability index estimation algorithm was derived and applied to develop and implement a balance ability diagnosis system that can be used in daily life. METHODS: The system integrated an approach based on sensory function interaction, called the clinical test of sensory interaction with balance. A capacitance and resistance sensing type force mat was fabricated, and a stability index prediction algorithm was developed and applied using the center of pressure variables. The stability index prediction algorithm derived a center of pressure variable for 103 elderly people by Nintendo Wii Balance Board to predict the stability index of the balance system (Biodex SD), and the accuracy of this approach was confirmed. RESULTS: As a result of testing with the test set, the linear regression model confirmed that the r-value ranged between 0.943 and 0.983. To confirm the similarity between the WBB and the flexible force mat, each measured center of pressure value was inputted and calculated in the developed regression model, and the result of the correlation coefficient validation confirmed an r-value of 0.96. CONCLUSION: The system developed in this study will be applicable to daily life in the home in the form of a floor mat.

Electrophysiological correlates of object-repetition effects: sLORETA imaging with 64-channel EEG and individual MRI.

BACKGROUND: We investigated the electrophysiological correlates of object-repetition effects using an object categorization task, standardized low-resolution electromagnetic tomography (sLORETA), and individual magnetic resonance imaging. Sixteen healthy adults participated, and a total of 396 line drawings of living and non-living objects were used as stimuli. Of these stimuli, 274 were presented only once, and 122 were repeated after one to five intervening pictures. Participants were asked to categorize the objects as living or non-living things by pressing one of two buttons. RESULTS: The old/new effect (i.e., a faster response time and more positive potentials in response to repeated stimuli than to stimuli initially presented) was observed at 350-550 ms post-stimulus. The distributions of cortical sources for the old and new stimuli were very similar at 250-650 ms after stimulus-onset. Activation in the right middle occipital gyrus/cuneus, right fusiform gyrus, left superior temporal gyrus, and right inferior frontal gyrus was significantly reduced in response to old compared with new stimuli at 250-350, 350-450, 450-550, and 550-650 ms after stimulus-onset, respectively. Priming in response time was correlated with the electrophysiological priming at left parietal area and repetition suppression at left superior temporal gyrus in 450-550 ms. CONCLUSIONS: These results suggest processing of repeated objects is facilitated by sharpening perceptual representation and by efficient detection or attentional control of repeated objects.

Inhibitory Control of Saccadic Eye Movements and Cognitive Impairment in Mild Cognitive Impairment.

Background: Mild cognitive impairment (MCI) may occur due to several forms of neurodegenerative diseases and non-degenerative conditions and is associated with cognitive impairment that does not affect everyday activities. For a timely diagnosis of MCI to prevent progression to dementia, a screening tool of fast, low-cost and easy access is needed. Recent research on eye movement hints it a potential application for the MCI screening. However, the precise extent of cognitive function decline and eye-movement control alterations in patients with MCI is still unclear. Objective: This study examined executive control deficits and saccade behavioral changes in patients with MCI using comprehensive neuropsychological assessment and interleaved saccade paradigms. Methods: Patients with MCI (n = 79) and age-matched cognitively healthy controls (HC) (n = 170) completed four saccadic eye-movement paradigms: prosaccade (PS)/antisaccade (AS), Go/No-go, and a battery of neuropsychological tests. Results: The findings revealed significantly longer latency in patients with MCI than in HC during the PS task. Additionally, patients with MCI had a lower proportion of correct responses and a marked increase in inhibition errors for both PS/AS and Go/No-go tasks. Furthermore, when patients with MCI made errors, they failed to self-correct many of these inhibition errors. In addition to the increase in inhibition errors and uncorrected inhibition errors, patients with MCI demonstrated a trend toward increased correction latencies. We also showed a relationship between neuropsychological scores and correct and error saccade responses. Conclusion: Our results demonstrate that, similar to patients with Alzheimer's dementia (AD), patients with MCI generate a high proportion of erroneous saccades toward the prepotent target and fail to self-correct many of these errors, which is consistent with an impairment of inhibitory control and error monitoring. Significance: The interleaved PS/AS and Go/No-go paradigms are sensitive and objective at detecting subtle cognitive deficits and saccade changes in MCI, indicating that these saccadic eye movement paradigms have clinical potential as a screening tool for MCI.

Estimating objective (EEG) and subjective (SSQ) cybersickness in people with susceptibility to motion sickness.

Cybersickness refers to the uncomfortable side effects, such as headaches, dizziness, and nausea, felt while experiencing virtual reality (VR). This study investigated cybersickness in people with sensitivity to motion sickness using electroencephalography (EEG), the Simulator Sickness Questionnaire (SSQ), and simple VR content. Based on the scores from the Motion Sickness Susceptibility Questionnaire (MSSQ), 40 males in their twenties were selected as the sensitive group (n = 20) and non-sensitive group (n = 20). The experiment contained two conditions: a baseline condition representing a resting state and a cybersickness condition in which watching VR content induced cybersickness. The SSQ score increased significantly after watching the VR content in both groups. The sensitive group showed significantly lower absolute power in the beta and gamma bands than the non-sensitive group. The cybersickness condition showed significantly increased delta and decreased alpha compared to the baseline condition. We evaluated EEG and SSQ to identify subjective symptoms and objective physiological changes associated with cybersickness.

Electroencephalogram microstates and functional connectivity of cybersickness.

Virtual reality (VR) is a rapidly developing technology that simulates the real world. However, for some cybersickness-susceptible people, VR still has an unanswered problem-cybersickness-which becomes the main obstacle for users and content makers. Sensory conflict theory is a widely accepted theory for cybersickness. It proposes that conflict between afferent signals and internal models can cause cybersickness. This study analyzes the brain states that determine cybersickness occurrence and related uncomfortable feelings. Furthermore, we use the electroencephalogram (EEG) microstates and functional connectivity approach based on the sensory conflict theory. The microstate approach is a time-space analysis method that allows signals to be divided into several temporarily stable states, simultaneously allowing for the exploration of short- and long-range signals. These temporal dynamics can show the disturbances in mental processes associated with neurological and psychiatric conditions of cybersickness. Furthermore, the functional connectivity approach gives us in-depth insight and relationships between the sources related to cybersickness. We recruited 40 males (24.1 ± 2.3 years), and they watched a VR video on a curved computer monitor for 10 min to experience cybersickness. We recorded the 5-min resting state EEG (baseline condition) and 10-min EEG while watching the VR video (task condition). Then, we performed a microstate analysis, focusing on two temporal parameters: mean duration and global explained variance (GEV). Finally, we obtained the functional connectivity data using eLoreta and lagged phase synchronization (LPS). We discovered five sets of microstates (A-E), including four widely reported canonical microstates (A-D), during baseline and task conditions. The average duration increased in microstates A and B, which is related to the visual and auditory networks. The GEV and duration decreased in microstate C, whereas those in microstate D increased. Microstate C is related to the default mode network (DMN) and D to the attention network. The temporal dynamics of the microstate parameters are from cybersickness disturbing the sensory, DMN, and attention networks. In the functional connectivity part, the LPS between the left and right parietal operculum (OP) significantly decreased (p < 0.05) compared with the baseline condition. Furthermore, the connectivity between the right OP and V5 significantly decreased (p < 0.05). These results also support the disturbance of the sensory network because a conflict between the visual (V5) and vestibular system (OP) causes cybersickness. Changes in the microstates and functional connectivity support the sensory conflict theory. These results may provide additional information in understanding brain dynamics during cybersickness.

Self-assembly of pyrazine-containing tetrachloroacenes.

In this paper, we report self-assembly of tetrachloroacenes containing pyrazine moieties. The title compounds, phenazine and bisphenazine substituted with four chlorine atoms for increased electron deficiency and alkyloxy side groups for solubility, demonstrated excellent gelation ability in select organic solvents. The assembled structure of these two series of compounds exhibited a morphological difference. Tetrachlorophenazine containing hexadecyloxy side groups induced rigid microbelts, while more extensive entanglement of thinner, more flexible fibers was observed from tetrachlorobisphenazine compounds, characterized by scanning electron microscopy. Tetrachlorophenazine and tetrachlorobisphenazine gels showed quite different emission behavior compared to their solution state. A strong, red-shifted emission compared to that of its diluted solution state was observed from the gel of tetrachlorophenazine. We have ascertained this is a result of J-aggregate formation. From the crystal structure of a model compound, it was found that tetrachlorophenazine cores adopt π-π stacking with a short stacking distance of 3.38 Å, enabling significant intermolecular π-orbital overlap. In addition, the π-cores were displaced longitudinally, indicative of J-aggregate formation. Surprisingly, the gel of tetrachlorobisphenazine showed fluorescence comparable to that of its dilute solution, suggesting that such a close packing of the π-cores may not be possible due to the bulky tert-butyl substituents.

Test-retest reliability of the virtual reality sickness evaluation using electroencephalography (EEG).

No reliable quantitative and objective measurement method for virtual reality (VR) sickness has been firmly established to date. Electroencephalography (EEG) may be a strong candidate to evaluate VR sickness objectively. However, no test-retest evaluation has been made for VR sickness using EEG. To recruit VR sickness-sensitive participants, we tested 858 participants (age = 20's-50's) using the Motion Sickness Susceptibility Questionnaire (MSSQ). Among them, we recruited 21 males (average age = 25.0) who obtained the 75th percentile of scores on the MSSQ (32.9 ± 5.7). VR sickness was evaluated twice (one week apart) using EEG with VR video content designed to cause VR sickness. A Simulation Sickness Questionnaire (SSQ) was also used to evaluate VR sickness. In terms of the reliability of EEG, ICC and Cronbach's alpha analyses showed that three waves (delta, theta, and alpha) were consistent in two areas (frontal and central). A significant difference in EEG was also found repeatedly between the baseline and VR sickness (delta, theta, and alpha) in two areas (frontal and central). We evaluated EEG for its reliability and found specific waves and areas that showed good consistency and significant changes associated with VR sickness. These findings may support further research of VR sickness evaluation.

Organogels from functionalized T-shaped pi-conjugated bisphenazines.

This paper reports the electronic and organogelation properties of novel T-shaped bisphenazines functionalized with alkyl side groups and small peripheral cyano (CN) or aldehyde (CHO) substituents. UV-vis spectroscopy and cyclic voltammetry show the effect of the position, type, and number of the peripheral substituents on the electronic properties of the entire system. Interesting organogelation properties including a thixotropic behavior were observed from these T-shaped bisphenazines. We describe important findings from an in-depth characterization on the fibers formed by organogelation: (i) The position of the peripheral substituents influences the fiber morphology by modulating the intermolecular CN (or CHO) interaction and the pi-pi stacking. (ii) Compounds with CHO groups form islands of fiber aggregates, which is not the case for compounds with CN groups. (iii) Decyl-substituted compounds show higher gelation temperatures (i.e., produce stronger gels) than hexadecyl-substituted ones. (iv) The thixotropic behavior originates from an extensive three-dimensional entanglement of very thin, flexible fibers.

Tuning the electronic properties of phenazine and bisphenazine derivatives: a theoretical and experimental investigation.

The current study employs both theoretical and experimental methods to characterize the electronic properties associated with peripheral substitution on asymmetric phenazine and bisphenazine systems. Substituent groups include F, Cl, Br, and NO(2) with substitutions made at different positions on the heteroaromatic rings in order to assess the effects of substituent type as well as substituent position on the electronic properties. A comprehensive investigation on halogen substituents was conducted to determine the efficacy of either Cl or Br, specifically these substituents' ability to lower LUMO energies relative to F. HOMO and LUMO energy levels have been theoretically characterized using Density Functional Theory (B3LYP) with both 6-31G* and 6-31+G* basis sets. Theoretical results are compared to results obtained using UV-Vis spectroscopy and cyclic voltammetry. Additionally, a theoretical comparison of the smaller, phenazine molecule and the larger bisphenazine system has been conducted to ascertain whether the smaller system can be used to model the electronic properties of the larger molecule.

The Dynamic Properties of a Brain Network During Spatial Working Memory Tasks in College Students With ADHD Traits.

This study investigated deficits of spatial working memory in college students with attention-deficit/hyperactivity disorder (ADHD) traits using event-related potentials (ERPs) and the spatial 2-back task. We also computed sensory-level activity using EEG data and investigated theta and alpha neural oscillations, phase-locking values (PLV), and brain networks. Based on the scores from the Adult ADHD Self-Report Scale (ASRS) and Conners' Adult ADHD Rating Scales (CAARS), an ADHD-trait group (n = 40) and a normal control group (n = 41) were selected. Participants were required to respond to whether the presented stimulus was at the same location as that presented two trials earlier. The ADHD-trait group showed significantly slower response times than the control group in the spatial 2-back task. In terms of spectrum, the ADHD-trait group showed significantly reduced theta power than the control group. In contrast, the ADHD-trait group exhibited an increased alpha power compared to the control group with the 250-1000 ms interval after stimulus onset. In terms of the PLV, the ADHD-trait group showed significantly weaker theta phase synchrony and fewer connection numbers in frontal-occipital areas than the control group. In terms of the theta brain network, the ADHD-trait group showed a significantly lower clustering coefficient and longer characteristic path length than the control group for the theta band. The present results indicate that college students with ADHD traits have deficits in spatial working memory and that these abnormal activities in neural oscillation, functional connectivity, and the network may contribute to spatial working memory deficits.

Substituent effect on the electronic properties and morphologies of self-assembling bisphenazine derivatives.

Tuning electronic properties and morphologies: We report a unique design platform of n-type organic semiconductors based on asymmetrically substituted bisphenazines that enable tuning of both electronic properties and morphologies of 1D nanostructures (see figure) by using small substituents with various sizes and electronic demands.This paper reports the synthesis and characterization of novel self-assembling n-type organic semiconductors based on asymmetrically substituted bisphenazines with various functional groups of different size, electron-withdrawing ability, and conjugation length. The overarching objective of this research is to tune electronic properties and morphologies of self-assembled structures of this system simultaneously, which offers a potentially useful platform for future optoelectronic applications. The thermal, optical, and electrochemical properties associated with different substituents were studied by differential scanning calorimetry (DSC), UV-visible and fluorescence spectroscopy, and cyclic voltammetry (CV). Electronic properties were calculated using density functional theory, and results were compared to experimental HOMO, LUMO, and energy gaps. The one-dimensional (1D) self-assembly properties of these new n-type molecules are discussed in terms of the type of peripheral substituents, alkyl side group length, and assembly conditions. This study includes extensive investigations by scanning electron microscopy (SEM) and X-ray diffraction (XRD).

The neuropsychological profile of a subclinical obsessive-compulsive sample.

We investigated the neuropsychological profile of subjects in a subclinical obsessive-compulsive disorder (OCD) sample. Psychometrically defined subclinical obsessive-compulsive (n = 21) and control (n = 22) subjects were examined. Comprehensive neuropsychological tests evaluating verbal/nonverbal memory, attention, and executive function were administered. The subclinical obsessive-compulsive group showed poorer performances on the Wisconsin Card Sorting Test (WCST), F(1, 41) = 13.80, p < .001, and Trail-Making Test (TMT), F(1, 41) = 5.48, p < .05, compared with the control group. The subclinical obsessive-compulsive group showed higher rates of total errors, perseverative errors, and perseverative responses. In addition, the subclinical obsessive-compulsive group committed a greater number of errors in the TMT. However, the groups showed no performance differences in the TMT after controlling for the effects of depression and anxiety, F(1, 39) = 0.11, p = .739. These results suggest that subclinical obsessive-compulsives seemed to display deficits in executive functioning. This neuropsychological profile is consistent with current theories proposing that executive dysfunction may serve as the pathophysiological mechanism underlying the development of obsessive-compulsive disorder.

An Event-Related Potential Study of Decision-Making and Feedback Utilization in Female College Students Who Binge Drink.

This study investigated the ability to use feedback for decision-making in female college students who binge drink (BD) using the iowa gambling task (IGT) and event-related potentials (ERPs). Twenty-seven binge drinkers and 23 non-binge drinkers (non-BD) were identified based on scores on the Korean version of the Alcohol Use Disorder Test and the Alcohol Use Questionnaire. The IGT consists of four cards, including two cards that result in a net loss, with large immediate gains but greater losses in the long term, and two cards that result in a net gain, with small immediate gains but reduced losses in the long term. Participants were required to choose one card at a time to maximize profit until the end of the task while avoiding losses. The BD group showed a significantly lower total net score than the non-BD group, indicating that the BD group chose more disadvantageous cards. The BD group showed significantly smaller ΔFRN amplitudes [difference in amplitudes of feedback-related negativity (FRN) between gain and loss feedback] but not in P3 amplitudes. Additionally, ΔFRN amplitudes in the fronto-central area were positively correlated with the total net score and net scores for sectors 4 and 5. Thus, total net scores and later performance on the IGT increased as ΔFRN amplitudes from the fronto-central area increased. FRN is known to reflect early feedback evaluation employing a bottom-up mechanism, whereas P3 is known to reflect late feedback processing and allocation of attentional resources using a top-down mechanism. These results indicate that college students who binge drink have deficits in early evaluation of positive or negative feedback and that this deficit may be related to decision-making deficits.

Reduced Theta-Band Power and Phase Synchrony during Explicit Verbal Memory Tasks in Female, Non-Clinical Individuals with Schizotypal Traits.

The study of non-clinical individuals with schizotypal traits has been considered to provide a promising endophenotypic approach to understanding schizophrenia, because schizophrenia is highly heterogeneous, and a number of confounding factors may affect neuropsychological performance. Here, we investigated whether deficits in explicit verbal memory in individuals with schizotypal traits are associated with abnormalities in the local and inter-regional synchrony of brain activity. Memory deficits have been recognized as a core problem in schizophrenia, and previous studies have consistently shown explicit verbal memory impairment in schizophrenic patients. However, the mechanism of this impairment has not been fully revealed. Seventeen individuals with schizotypal traits and 17 age-matched, normal controls participated. Multichannel event-related electroencephalograms (EEGs) were recorded while the subjects performed a continuous recognition task. Event-related spectral perturbations (ERSPs) and inter-regional theta-band phase locking values (TPLVs) were investigated to determine the differences in local and global neural synchrony between the two subject groups. Additionally, the connection patterns of the TPLVs were quantitatively analyzed using graph theory measures. An old/new effect was found in the induced theta-band ERSP in both groups. However, the difference between the old and new was larger in normal controls than in schizotypal trait group. The tendency of elevated old/new effect in normal controls was observed in anterior-posterior theta-band phase synchrony as well. Our results suggest that explicit memory deficits observed in schizophrenia patients can also be found in non-clinical individuals with psychometrically defined schizotypal traits.

Deficits in error-monitoring by college students with schizotypal traits: an event-related potential study.

The present study used event-related potentials (ERPs) to investigate deficits in error-monitoring by college students with schizotypal traits. Scores on the Schizotypal Personality Questionnaire (SPQ) were used to categorize the participants into schizotypal-trait (n = 17) and normal control (n = 20) groups. The error-monitoring abilities of the participants were evaluated using the Simon task, which consists of congruent (locations of stimulus and response are the same) and incongruent (locations of stimulus and response are different) conditions. The schizotypal-trait group committed more errors on the Simon task and exhibited smaller error-related negativity (ERN) amplitudes than did the control group. Additionally, ERN amplitude measured at FCz was negatively correlated with the error rate on the Simon task in the schizotypal-trait group but not in the control group. The two groups did not differ in terms of correct-related potentials (CRN), error positivity (Pe) and correct-related positivity (Pc) amplitudes. The present results indicate that individuals with schizotypal traits have deficits in error-monitoring and that reduced ERN amplitudes may represent a biological marker of schizophrenia.

Electrophysiological correlates of local-global visual processing in college students with schizotypal traits: an event-related potential study.

We examined local-global visual processing in college students with schizotypal traits using event-related potentials (ERPs). Local-global processing was assessed using a divided-attention task, in which large numbers (global level) composed of small numbers (local level) were presented. The control group had faster response time (RT) and more accurate responses to global-level than to local-level stimuli, whereas RT and accuracy did not differ between levels in the schizotypal-trait group. N150 amplitudes for local stimuli were larger than those for global stimuli in the schizotypal-trait group, whereas N150 amplitudes did not differ between levels in the control group. P300 amplitudes for local stimuli were larger relative to global stimuli in the control group, whereas P300 amplitudes did not differ between levels in the schizotypal-trait group. These results indicate that the global precedence effect was reduced in the schizotypal-trait group, possibly because of local-biased visual processing or difficulty in global processing.