Early Event-related Potential Components Research Articles

Aberrant early visual neural activity and brain-behavior relationships in anorexia nervosa and body dysmorphic disorder.

Background: Body dysmorphic disorder (BDD) and anorexia nervosa (AN) share the clinical symptom of disturbed body image, which may be a function of perceptual distortions. Previous studies suggest visual or visuospatial processing abnormalities may be contributory, but have been unable to discern whether these occur early or late in the visual processing stream. We used electroencephalography (EEG) and visual event related potentials (ERP) to investigate early perceptual neural activity associated with processing visual stimuli.Methods: We performed EEG on 20 AN, 20 BDD, 20 healthy controls, all unmedicated. In order to probe configural/holistic and detailed processing, participants viewed photographs of faces and houses that were unaltered or filtered to low or high spatial frequencies, respectively. We calculated the early ERP components P100 and N170, and compared amplitudes and latencies among groups.Results: P100 amplitudes were smaller in AN than BDD and healthy controls, regardless of spatial frequency or stimulus type (faces or houses). Similarly, N170 latencies were longer in AN than healthy controls, regardless of spatial frequency or stimulus type, with a similar pattern in BDD at trend level significance. N170 amplitudes were smaller in AN than controls for high and normal spatial frequency images, and smaller in BDD than controls for normal spatial frequency images, regardless of stimulus type. Poor insight correlated with lower N170 amplitudes for normal and low spatial frequency faces in the BDD group.Conclusions: Individuals with AN exhibit abnormal early visual system activity, consistent with reduced configural processing and enhanced detailed processing. This is evident regardless of whether the stimuli are appearance–or non-appearance-related, and thus may be a reflection of general, early perceptual abnormalities. As N170 amplitude could be a marker of structural encoding of faces, lower values may be associated with perceptual distortions and could contribute to poor insight in BDD. Future studies may explore visual ERP measures as potential biomarkers of illness phenotype.

Higher, faster, worse? An event-related potentials study of affective picture processing in migraine.

Migraine is a disorder of periodic disabling headache. Facilitated cortical responsivity has been suggested as one predisposing factor. Although the underlying mechanisms of migraine attack onsets are not fully understood, facilitated cortical responsivity has been suggested as one predisposing factor. Here, we investigate if enhanced cortical responsivity is reflected in altered event-related potentials during processing of complex pictures. Altogether, 16 migraine patients and 16 healthy volunteers participated in this study. Each patient had a diagnosed migraine and was headache- and medication-free for the study. Participants watched positive, negative and neutral pictures from the international affective picture system. An electroencephalogram was recorded during picture presentation. Afterwards, participants were asked to rate the pictures for valence and arousal. Migraine patients showed significantly more negative-going early event-related potential components from 100 ms to 180 ms to all picture categories over occipital regions as well as more positive-going late potentials over central regions. Patients and controls did not differ in valence and arousal ratings for the international-affective picture system. Patients with migraine seem to react cortically more intensely to all kinds of pictorial stimuli, regardless of emotional content. This facilitated processing may be related to the high cortical responsivity shown in various other event-related potential studies and might contribute to the recurring intense headache attacks.

Predictive coding of visual–auditory and motor-auditory events: An electrophysiological study

The amplitude of auditory components of the event-related potential (ERP) is attenuated when sounds are self-generated compared to externally generated sounds. This effect has been ascribed to internal forward modals predicting the sensory consequences of one’s own motor actions. Auditory potentials are also attenuated when a sound is accompanied by a video of anticipatory visual motion that reliably predicts the sound. Here, we investigated whether the neural underpinnings of prediction of upcoming auditory stimuli are similar for motor-auditory (MA) and visual–auditory (VA) events using a stimulus omission paradigm. In the MA condition, a finger tap triggered the sound of a handclap whereas in the VA condition the same sound was accompanied by a video showing the handclap. In both conditions, the auditory stimulus was omitted in either 50% or 12% of the trials. These auditory omissions induced early and mid-latency ERP components (oN1 and oN2, presumably reflecting prediction and prediction error), and subsequent higher-order error evaluation processes. The oN1 and oN2 of MA and VA were alike in amplitude, topography, and neural sources despite that the origin of the prediction stems from different brain areas (motor versus visual cortex). This suggests that MA and VA predictions activate a sensory template of the sound in auditory cortex.This article is part of a Special Issue entitled SI: Prediction and Attention.

Sustained maintenance of somatotopic information in brain regions recruited by tactile working memory.

To adaptively guide ongoing behavior, representations in working memory (WM) often have to be modified in line with changing task demands. We used event-related potentials (ERPs) to demonstrate that tactile WM representations are stored in modality-specific cortical regions, that the goal-directed modulation of these representations is mediated through hemispheric-specific activation of somatosensory areas, and that the rehearsal of somatotopic coordinates in memory is accomplished by modality-specific spatial attention mechanisms. Participants encoded two tactile sample stimuli presented simultaneously to the left and right hands, before visual retro-cues indicated which of these stimuli had to be retained to be matched with a subsequent test stimulus on the same hand. Retro-cues triggered a sustained tactile contralateral delay activity component with a scalp topography over somatosensory cortex contralateral to the cued hand. Early somatosensory ERP components to task-irrelevant probe stimuli (that were presented after the retro-cues) and to subsequent test stimuli were enhanced when these stimuli appeared at the currently memorized location relative to other locations on the cued hand, demonstrating that a precise focus of spatial attention was established during the selective maintenance of tactile events in WM. These effects were observed regardless of whether participants performed the matching task with uncrossed or crossed hands, indicating that WM representations in this task were based on somatotopic rather than allocentric spatial coordinates. In conclusion, spatial rehearsal in tactile WM operates within somatotopically organized sensory brain areas that have been recruited for information storage.

The Effect of Unconscious Emotional Faces on Spatial Attention: an ERP Study

Event Abstract Back to Event The Effect of Unconscious Emotional Faces on Spatial Attention: an ERP Study Ling Li1*, Xianxian Kong1 and Zhenlan Jin1 1 University of Electronic Science and Technology of China, Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology, China Different emotional face may cause disparate influence to cognitive functions, including attention and working memory. We examined unconscious emotional effect (happy and fear faces) on spatial attention with a classical spatial selective attention task by measuring behavioral and event-related potential (ERP) responses. Emotional faces of big (2.7 by 2.3 degree) or small (2.1 by 1.8 degree) sizes were rapidly presented at the right or left visual field randomly while subjects attended to one visual field. Subjects were required to press a button at the detection of a small face in the attended visual field. Behavioral results showed lower accuracies of fear face detection than happy and neutral faces. Early ERP components (P1, N1) showed enhanced posterior activities in attended condition compared to unattended condition and increased activity to fear face compared to happy and neutral faces at the vertex area. In addition, early ERP showed the interaction between emotion and attention, in which neutral faces showed increased activity compared to fear faces at attended condition while emotional faces showed increased activity than neutral face at unattended condition at posterior area. Taken together these findings provide evidence that unconscious emotional faces can attract attention automatically, and positive and negative emotional valence may cause different effect on spatial attention. Unconscious fear emotion may disturb ongoing task more by distracting attentional resources. Keywords: emotion, unconscious, spatial attention, ERP, emotional face Conference: XII International Conference on Cognitive Neuroscience (ICON-XII), Brisbane, Queensland, Australia, 27 Jul - 31 Jul, 2014. Presentation Type: Poster Topic: Attention Citation: Li L, Kong X and Jin Z (2015). The Effect of Unconscious Emotional Faces on Spatial Attention: an ERP Study. Conference Abstract: XII International Conference on Cognitive Neuroscience (ICON-XII). doi: 10.3389/conf.fnhum.2015.217.00214 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 19 Feb 2015; Published Online: 24 Apr 2015. * Correspondence: Prof. Ling Li, University of Electronic Science and Technology of China, Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology, Chengdu, China, liling@uestc.edu.cn Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Ling Li Xianxian Kong Zhenlan Jin Google Ling Li Xianxian Kong Zhenlan Jin Google Scholar Ling Li Xianxian Kong Zhenlan Jin PubMed Ling Li Xianxian Kong Zhenlan Jin Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Sensory gain outperforms efficient readout mechanisms in predicting attention-related improvements in behavior.

Spatial attention has been postulated to facilitate perceptual processing via several different mechanisms. For instance, attention can amplify neural responses in sensory areas (sensory gain), mediate neural variability (noise modulation), or alter the manner in which sensory signals are selectively read out by postsensory decision mechanisms (efficient readout). Even in the context of simple behavioral tasks, it is unclear how well each of these mechanisms can account for the relationship between attention-modulated changes in behavior and neural activity because few studies have systematically mapped changes between stimulus intensity, attentional focus, neural activity, and behavioral performance. Here, we used a combination of psychophysics, event-related potentials (ERPs), and quantitative modeling to explicitly link attention-related changes in perceptual sensitivity with changes in the ERP amplitudes recorded from human observers. Spatial attention led to a multiplicative increase in the amplitude of an early sensory ERP component (the P1, peaking ∼80-130 ms poststimulus) and in the amplitude of the late positive deflection component (peaking ∼230-330 ms poststimulus). A simple model based on signal detection theory demonstrates that these multiplicative gain changes were sufficient to account for attention-related improvements in perceptual sensitivity, without a need to invoke noise modulation. Moreover, combining the observed multiplicative gain with a postsensory readout mechanism resulted in a significantly poorer description of the observed behavioral data. We conclude that, at least in the context of relatively simple visual discrimination tasks, spatial attention modulates perceptual sensitivity primarily by modulating the gain of neural responses during early sensory processing.

Expectations induced by natural-like temporal fluctuations are independent of attention decrement: Evidence from behavior and early visual evoked potentials

Temporal expectations and attention decrement affect human behavior in opposing ways: the former positively, the latter negatively yet both exhibit similar neural signatures – i.e., reduction in the early event-related potential components' amplitude – despite different underlying mechanisms. Furthermore, there is a significant and growing debate in the literature regarding the putative role of attention in the encoding of expectations in perception. The question then arises as to what are the behavioral and neural consequences, if any, of attention decrement on temporal expectations and related enhancement of sensory information processing.Here, we investigated behavioral performance and visual N1a, N1p and P1 components during a sustained attention reaction time task inducing attention decrement under two conditions. In one condition, the inter-stimulus intervals (ISIs) were randomly distributed to impede expectation effects while for the other, the ISI exhibited natural-like long-term correlations supposed to induce temporal expectations.Behavioral results show that natural-like fluctuations in ISI indeed induced faster RT due to temporal expectations. These temporal expectations were beneficial even under attention decrement circumstances. Further, temporal expectations were associated with reduced N1a amplitude while attention decrement was associated with reduced N1p amplitude. Our findings provide evidence that the effects of temporal expectations and attention decrement induced in a single task can be independent at the behavioral level, and are supported at separate information processing stages at the neural level in vision.

Children with a history of SLI show reduced sensitivity to audiovisual temporal asynchrony: an ERP study.

The authors examined whether school-age children with a history of specific language impairment (H-SLI), their peers with typical development (TD), and adults differ in sensitivity to audiovisual temporal asynchrony and whether such difference stems from the sensory encoding of audiovisual information. Fifteen H-SLI children, 15 TD children, and 15 adults judged whether a flashed explosion-shaped figure and a 2-kHz pure tone occurred simultaneously. The stimuli were presented at 0-, 100-, 200-, 300-, 400-, and 500-ms temporal offsets. This task was combined with EEG recordings. H-SLI children were profoundly less sensitive to temporal separations between auditory and visual modalities compared with their TD peers. Those H-SLI children who performed better at simultaneity judgment also had higher language aptitude. TD children were less accurate than adults, revealing a remarkably prolonged developmental course of the audiovisual temporal discrimination. Analysis of early event-related potential components suggested that poor sensory encoding was not a key factor in H-SLI children's reduced sensitivity to audiovisual asynchrony. Audiovisual temporal discrimination is impaired in H-SLI children and is still immature during mid-childhood in TD children. The present findings highlight the need for further evaluation of the role of atypical audiovisual processing in the development of SLI.

Effect of attentional load on audiovisual speech perception: evidence from ERPs.

Seeing articulatory movements influences perception of auditory speech. This is often reflected in a shortened latency of auditory event-related potentials (ERPs) generated in the auditory cortex. The present study addressed whether this early neural correlate of audiovisual interaction is modulated by attention. We recorded ERPs in 15 subjects while they were presented with auditory, visual, and audiovisual spoken syllables. Audiovisual stimuli consisted of incongruent auditory and visual components known to elicit a McGurk effect, i.e., a visually driven alteration in the auditory speech percept. In a Dual task condition, participants were asked to identify spoken syllables whilst monitoring a rapid visual stream of pictures for targets, i.e., they had to divide their attention. In a Single task condition, participants identified the syllables without any other tasks, i.e., they were asked to ignore the pictures and focus their attention fully on the spoken syllables. The McGurk effect was weaker in the Dual task than in the Single task condition, indicating an effect of attentional load on audiovisual speech perception. Early auditory ERP components, N1 and P2, peaked earlier to audiovisual stimuli than to auditory stimuli when attention was fully focused on syllables, indicating neurophysiological audiovisual interaction. This latency decrement was reduced when attention was loaded, suggesting that attention influences early neural processing of audiovisual speech. We conclude that reduced attention weakens the interaction between vision and audition in speech.

Age-related decline in bottom-up processing and selective attention in the very old.

Previous research demonstrating age-related deficits in selective attention have not included old-old adults, an increasingly important group to study. The current investigation compared event-related potentials in 15 young-old (65-79 years old) and 23 old-old (80-99 years old) subjects during a color-selective attention task. Subjects responded to target letters in a specified color (Attend) while ignoring letters in a different color (Ignore) under both low and high loads. There were no group differences in visual acuity, accuracy, reaction time, or latency of early event-related potential components. The old-old group showed a disruption in bottom-up processing, indexed by a substantially diminished posterior N1 (smaller amplitude). They also demonstrated markedly decreased modulation of bottom-up processing based on selected visual features, indexed by the posterior selection negativity (SN), with similar attenuation under both loads. In contrast, there were no group differences in frontally mediated attentional selection, measured by the anterior selection positivity (SP). There was a robust inverse relationship between the size of the SN and SP (the smaller the SN, the larger the SP), which may represent an anteriorly supported compensatory mechanism. In the absence of a decline in top-down modulation indexed by the SP, the diminished SN may reflect age-related degradation of early bottom-up visual processing in old-old adults.

N450 as a candidate neural marker for interference control deficits in children with learning disabilities

A deficit in the ability to suppress irrelevant or interfering stimuli may account for a variety of dysfunctional behaviors in children with learning disabilities (LD). However, neural correlates underlying this deficit in interference control in the LD are still unknown. In this study, we recruited a group of children with LD (age: 10.78±0.52) along with an age-matched control group (age: 10.74±0.86) and asked them to perform a numerical Stroop task. During the task, we used electroencephalogram (EEG) to record their event-related potentials (ERPs). We further evaluated performance of these children on a battery of tests, including the Academic Adaptability Test (AAT), an adapted Chinese version of Pupil Rating Scale (PRS), and Raven's Standard Progressive Matrices (SPM). Children's scores on recent math and Chinese exams were also obtained. Results showed that: 1) children with LD had worse performance in the incongruent condition of the numerical Stroop task suggesting that children with LD had interference control deficits but not basic numerical cognition; 2) children with LD had larger N450 effects on the frontal and posterior sites, but did not show any difference in early ERP components, suggesting that the behavioral difference was related with interference control rather than early visual perception processing; and 3) N450 effects were correlated with accuracy in the numerical Stroop task, performance in Raven's SPM, as well as school math performance. These results suggest that N450 can serve as a potential electrophysiology marker for identifying and potentially, providing targeted intervention for children with LD.

Phase noise reveals early category-specific modulation of the event-related potentials.

Previous studies have found that the amplitude of the early event-related potential (ERP) components evoked by faces, such as N170 and P2, changes systematically as a function of noise added to the stimuli. This change has been linked to an increased perceptual processing demand and to enhanced difficulty in perceptual decision making about faces. However, to date it has not yet been tested whether noise manipulation affects the neural correlates of decisions about face and non-face stimuli similarly. To this end, we measured the ERPs for faces and cars at three different phase noise levels. Subjects performed the same two-alternative age-discrimination task on stimuli chosen from young–old morphing continua that were created from faces as well as cars and were calibrated to lead to similar performances at each noise-level. Adding phase noise to the stimuli reduced performance and enhanced response latency for the two categories to the same extent. Parallel to that, phase noise reduced the amplitude and prolonged the latency of the face-specific N170 component. The amplitude of the P1 showed category-specific noise dependence: it was enhanced over the right hemisphere for cars and over the left hemisphere for faces as a result of adding phase noise to the stimuli, but remained stable across noise levels for cars over the left and for faces over the right hemisphere. Moreover, noise modulation altered the category-selectivity of the N170, while the P2 ERP component, typically associated with task decision difficulty, was larger for the more noisy stimuli regardless of stimulus category. Our results suggest that the category-specificity of noise-induced modulations of ERP responses starts at around 100 ms post-stimulus.

Neural correlates of own and close-other's name recognition: ERP evidence.

One’s own name seems to have a special status in the processing of incoming information. In event-related potential (ERP) studies this preferential status has mainly been associated with higher P300 to one’s own name than to other names. Some studies showed preferential responses to own name even for earlier ERP components. However, instead of just being self-specific, these effects could be related to the processing of any highly relevant and/or frequently encountered stimuli. If this is the case: (1) processing of other highly relevant and highly familiar names (e.g., names of friends, partners, siblings, etc.) should be associated with similar ERP responses as processing of one’s own name and (2) processing of own and close others’ names should result in larger amplitudes of early and late ERP components than processing of less relevant and less familiar names (e.g., names of famous people, names of strangers, etc.). To test this hypothesis we measured and analyzed ERPs from 62 scalp electrodes in 22 subjects. Subjects performed a speeded two-choice recognition task—familiar vs. unfamiliar—with one’s own name being treated as one of the familiar names. All stimuli were presented visually. We found that amplitudes of P200, N250 and P300 did not differ between one’s own and close-other’s names. Crucially, they were significantly larger to own and close-other’s names than to other names (unknown and famous for P300 and unknown for P200 and N250). Our findings suggest that preferential processing of one’s own name is due to its personal-relevance and/or familiarity factors. This pattern of results speaks for a common preference in processing of different kinds of socially relevant stimuli.

Temporal relation between top-down and bottom-up processing in lexical tone perception.

Speech perception entails both top-down processing that relies primarily on language experience and bottom-up processing that depends mainly on instant auditory input. Previous models of speech perception often claim that bottom-up processing occurs in an early time window, whereas top-down processing takes place in a late time window after stimulus onset. In this paper, we evaluated the temporal relation of both types of processing in lexical tone perception. We conducted a series of event-related potential (ERP) experiments that recruited Mandarin participants and adopted three experimental paradigms, namely dichotic listening, lexical decision with phonological priming, and semantic violation. By systematically analyzing the lateralization patterns of the early and late ERP components that are observed in these experiments, we discovered that: auditory processing of pitch variations in tones, as a bottom-up effect, elicited greater right hemisphere activation; in contrast, linguistic processing of lexical tones, as a top-down effect, elicited greater left hemisphere activation. We also found that both types of processing co-occurred in both the early (around 200 ms) and late (around 300–500 ms) time windows, which supported a parallel model of lexical tone perception. Unlike the previous view that language processing is special and performed by dedicated neural circuitry, our study have elucidated that language processing can be decomposed into general cognitive functions (e.g., sensory and memory) and share neural resources with these functions.

Amblyopic Deficit Beyond the Fovea: Delayed and Variable Single-Trial ERP Response Latencies, but Unaltered Amplitudes

Amblyopia was first described as a deficit of central vision. However, it has long been debated whether this dysfunction is limited to the fovea or whether extrafoveal vision is also affected, as studies concerning the latter are equivocal. The purpose of the study was to resolve this issue. We investigated the amblyopic effect on event-related potentials (ERPs) with foveal and perifoveal stimuli, either matched in size based on cortical magnification or presented as large annular stimuli. In two separate experiments we measured ERPs on amblyopic patients and control subjects using face images. Latency and amplitude of averaged ERPs and their single-trial distributions were analyzed. When the fovea was stimulated, latency and amplitude of the early averaged ERP components increased and were reduced, respectively, in the amblyopic compared with the fellow eye. Importantly, perifoveal stimulation also elicited similar amblyopic deficits, which were clearly significant in the case of using cortical magnification scaled stimuli. However, single-trial peak analysis revealed that foveal and perifoveal effects differed in nature: Peak amplitudes were reduced only in foveal stimulation, while latencies were delayed and jittered at both the fovea and perifovea. Event-related potentials obtained from fellow eyes were not significantly different from those of normal observers. Our findings revealed the existence of amblyopic deficits at the perifovea when the stimulated cortical area was matched in size to that of foveal stimulation. These deficits manifested themselves only in the temporal structure of the responses, unlike foveal deficits, which affected both component amplitude and latency.

Modulation of Response to Audiovisual Stimuli Presented Peripherally by Visually Cued Endogenous Temporal Attention: An Event-Related Potentials Study

Previous studies have used the cue-target paradigm to study the effect of the endogenous temporal attention on only visual or auditory stimuli. Furthermore, some studies found that the visual and auditory stimuli is not processed in isolation but produce coherent cognition in the brain when the visual and auditory stimuli are simultaneously presented. However, the effect of endogenous temporal attention on audiovisual (AV) stimuli processing is unclear. Utilizing the high temporal resolution of event-related potentials (ERPs), we used a central cue that can predict the time point (600 ms or 1800 ms) of audiovisual target to investigate whether endogenous temporal attention could modulate AV stimuli processing. The results showed that the endogenous temporal attention could not change the amplitude of the early ERP component in conditions of either short (600 ms) or long (1800 ms) cue-target intervals, indicating that the endogenous temporal attention had no effect on the early-stage of AV stimuli processing. However, the late ERP component showed differences between the short (600 ms) and long (1800 ms) cue-target intervals, supporting a model in which endogenous temporal attention might determine the late stage of AV stimuli processing. Keywords: Audiovisual stimuli, endogenous temporal attention, event-related potentials (ERPs), interstimulus interval (ISI).

Subclinical alexithymia modulates early audio-visual perceptive and attentional event-related potentials.

Introduction: Previous studies have highlighted the advantage of using audio–visual oddball tasks (instead of unimodal ones) in order to electrophysiologically index subclinical behavioral differences. Since alexithymia is highly prevalent in the general population, we investigated whether the use of various bimodal tasks could elicit emotional effects in low- vs. high-alexithymic scorers.Methods: Fifty students (33 females and 17 males) were split into groups based on low and high scores on the Toronto Alexithymia Scale (TAS-20). During event-related potential (ERP) recordings, they were exposed to three kinds of audio–visual oddball tasks: neutral-AVN—(geometrical forms and bips), animal-AVA—(dog and cock with their respective shouts), or emotional-AVE—(faces and voices) stimuli. In each condition, participants were asked to quickly detect deviant events occurring amongst a train of repeated and frequent matching stimuli (e.g., push a button when a sad face–voice pair appeared amongst a train of neutral face–voice pairs). P100, N100, and P300 components were analyzed: P100 refers to visual perceptive and attentional processing, N100 to auditory ones, and the P300 relates to response-related stages, involving memory processes.Results: High-alexithymic scorers presented a particular pattern of results when processing the emotional stimulations, reflected in early ERP components by increased P100 and N100 amplitudes in the emotional oddball tasks [P100: F(2, 48) = 20,319, p < 0.001; N100: F(2, 96) = 8,807, p = 0.001] as compared to the animal or neutral ones. Indeed, regarding the P100, subjects exhibited a higher amplitude in the AVE condition (8.717 μV), which was significantly different from that observed during the AVN condition (4.382 μV, p < 0.001). For the N100, the highest amplitude was found in the AVE condition (−4.035 μV) and the lowest was observed in the AVN condition (−2.687 μV, p = 0.003). However, no effect was found on the later P300 component.Conclusions: Our findings suggest that high-alexithymic scorers require heightened early attentional resources in comparison to low scorers, particularly when confronted with emotional bimodal stimuli.

Positive and negative symptom scores are correlated with activation in different brain regions during facial emotion perception in schizophrenia patients: A voxel-based sLORETA source activity study

Schizophrenia is one of the most devastating of all mental illnesses, and has dimensional characteristics that include both positive and negative symptoms. One problem reported in schizophrenia patients is that they tend to show deficits in face emotion processing, on which negative symptoms are thought to have stronger influence. In this study, four event-related potential (ERP) components (P100, N170, N250, and P300) and their source activities were analyzed using EEG data acquired from 23 schizophrenia patients while they were presented with facial emotion picture stimuli. Correlations between positive and negative syndrome scale (PANSS) scores and source activations during facial emotion processing were calculated to identify the brain areas affected by symptom scores. Our analysis demonstrates that PANSS positive scores are negatively correlated with major areas of the left temporal lobule for early ERP components (P100, N170) and with the right middle frontal lobule for a later component (N250), which indicates that positive symptoms affect both early face processing and facial emotion processing. On the other hand, PANSS negative scores are negatively correlated with several clustered regions, including the left fusiform gyrus (at P100), most of which are not overlapped with regions showing correlations with PANSS positive scores. Our results suggest that positive and negative symptoms affect independent brain regions during facial emotion processing, which may help to explain the heterogeneous characteristics of schizophrenia.

Early visual ERP sensitivity to the species and animacy of faces

Assessing the agency of potential actors in the visual world is a critically important aspect of social cognition. Adult observers are generally capable of distinguishing real faces from artificial faces (even allowing for recent advances in graphics technology and motion capture); even small deviations from real facial appearance can lead to profound effects on face recognition. Presently, we examined how early components of visual event-related potentials (ERPs) are affected by the “life” in human faces and animal faces. We presented participants with real and artificial faces of humans and dogs, and analyzed the response properties of the P100 and the N170 as a function of stimulus appearance and task (species categorization vs. animacy categorization). The P100 exhibited sensitivity to face species and animacy. We found that the N170’s differential responses to human faces vs. dog faces depended on the task participants’ performed. Also, the effect of species was only evident for real faces of humans and dogs, failing to obtain with artificial faces. These results suggest that face animacy does modulate early components of visual ERPs—the N170 is not merely a crude face detector, but reflects the tuning of the visual system to natural face appearance.

Illumination influences working memory: An EEG study

Illumination conditions appear to influence working efficacy in everyday life. In the present study, we obtained electroencephalogram (EEG) correlates of working-memory load, and investigated how these waveforms are modulated by illumination conditions. We hypothesized that illumination conditions may affect cognitive performance. We designed an EEG study to monitor and record participants’ EEG during the Sternberg working memory task under four different illumination conditions. Illumination conditions were generated with a factorial design of two color-temperatures (3000 and 7100K) by two illuminance levels (150 and 700lx). During a working memory task, we observed that high illuminance led to significantly lower frontal EEG theta activity than did low illuminance. These differences persisted despite no significant difference in task performance between illumination conditions. We found that the latency of an early event-related potential component, such as N1, was significantly modulated by the illumination condition. The fact that the illumination condition affects brain activity but not behavioral performance suggests that the lighting conditions used in the present study did not influence the performance stage of behavioral processing. Nevertheless, our findings provide objective evidence that illumination conditions modulate brain activity. Further studies are necessary to refine the optimal lighting parameters for facilitating working memory.