N170 Amplitude Research Articles

N170 reflects visual familiarity and automatic sublexical phonological access in L2 written word processing

AbstractThe literature has mixed reports on whether the N170, an early visual ERP response to words, signifies orthographic and/or phonological processing, and whether these effects are moderated by script and language expertise. In this study, native Chinese readers, Japanese–Chinese, and Korean–Chinese bilingual readers performed a one-back repetition detection task with single Chinese characters that differed in phonological regularity status. Results using linear mixed effects models showed that Korean–Chinese readers had bilateral N170 response, while native Chinese and Japanese–Chinese groups had left-lateralized N170, with stronger left lateralization in native Chinese than Japanese–Chinese readers. Additionally, across groups, irregular characters had bilateral increase in N170 amplitudes compared to regular characters. These results suggested that visual familiarity to a script rather than orthography-phonology mapping determined the left lateralization of the N170 response, while there was automatic access to sublexical phonology in the N170 time window in native and non-native readers alike.

EPOC outside the shield: comparing the performance of a consumer-grade EEG device in shielded and unshielded environments

Low-cost, portable electroencephalography (EEG) devices have become commercially available in the last 10 years. One such system, Emotiv’s EPOC, has been modified to allow event-related potential (ERP) research. Although the EPOC has been shown to provide data comparable to research-grade equipment and has been used in real-world settings, how EPOC performs without the electrical shielding, commonly used in research-grade laboratories, is yet to be systematically tested. In the current article we address this gap by conducting a simple EEG experiment in shielded and unshielded contexts. Participants (n = 13, mean age = 23.2 years, SD = 7.9) monitored the presentation of human versus wristwatch faces, responding whether the images were inverted or not. This method elicited the face-sensitive N170 ERP. In both shielded and unshielded contexts, the N170 amplitude was larger when participants viewed human faces and peaked later when a human face was inverted. More importantly, Bayesian analysis showed no difference in the N170 measured in the shielded and unshielded contexts. Further, the signal recorded in both contexts was highly correlated. The EPOC appears to reliably record EEG signals without a purpose-built electrically-shielded room.

Gender differences in subliminal affective face priming: A high-density ERP study.

IntroductionSubliminal affective priming effects (SAPEs) refer to the phenomenon by which the presentation of an affective prime stimulus influences the subsequent affective evaluation of a target stimulus. Previous studies have reported that unconsciously processed stimuli affect behavioral performance more than consciously processed stimuli. However, the impact of SAPEs on the face‐specific N170 component is unclear. We studied how SAPEs for fearful faces affected the N170 for subsequent supraliminal target faces using event‐related potentials (ERPs).MethodsJapanese adults (n = 44, 20 females) participated in this study. Subliminal prime faces (neutral or fearful) were presented for 17 ms, followed by a backward mask for 283 ms and 800 ms target faces (neutral, emotionally ambiguous, or fearful). 128‐channel ERPs were recorded while participants judged the expression of target faces as neutral or fearful. Response rates and response times were also measured for assessing behavioral alterations.ResultsAlthough the behavioral results revealed no evidence of SAPEs, we found gender‐related SAPEs in right N170 amplitude. Specifically, female participants exhibited enhanced right N170 amplitude for emotionally neutral faces primed by fearful faces, while male participants exhibited decreased N170 amplitude in fearful prime trials with fearful target faces. Male participants exhibited significant correlations between N170 amplitude and behavioral response time in the fearful prime‐neutral target condition.ConclusionsOur ERP results suggest the existence of a gender difference in target‐face processing preceded by subliminally presented face stimuli in the right occipito‐temporal region.

Central nervous activity during implicit processing of emotional face expressions in fibromyalgia syndrome

ObjectiveFibromyalgia syndrome (FMS) is characterized by chronic widespread pain accompanied by symptoms like fatigue, insomnia, depression, anxiety and cognitive impairments. In addition to central nervous pain sensitization, emotional dysregulation may be involved in FMS pathogenesis. This study investigated central nervous correlates of affective and attentional processing in FMS using an implicit task. MethodsEvent-related potentials (ERPs) of the EEG were recorded in 25 FMS patients and 37 healthy controls while they had to name the frame color of pictures displaying emotional expressions (angry, painful, happy, neutral). The actual picture had to be ingored. Symptoms of pain, depression and anxiety were also assessed. ResultsPatients exhibited smaller P2 and late positive potential (LPP) amplitudes, and a greater N250 amplitude, than controls. The N250 amplitude varied according to the emotional expressions displayed in patients, but not in controls. No group differences arose for the P1 or N170 amplitudes. Patients had longer reaction times and made more errors on the task; task performance was more closely related to pain severity than to other symptoms. ConclusionThe reduced P2 and LPP amplitudes indicate deficient short-term mobilization of attentional resources and sustained attention in FMS; the greater N250 amplitude may reflect greater engagement in the decoding of complex facial features, which is necessary to compensate for attentional impairments. Affective modulation of the N250 suggests that the neural mechanisms underlying complex visual processes are particularly susceptible to emotional influences in FMS. The behavioral data confirm attentional deficits in the disorder and implicate clinical pain therein.

Alterations of novelty processing in major depressive disorder

• Disproportionate allocation of cognitive resources in individuals with Major Depressive Disorder. • Dysfunction in reorienting attentional resources following the onset of novel auditory stimuli. • High state anxiety may impact N200 amplitude in individuals diagnosed with major depressive disorder and comorbid anxiety.

Physiological and Medico-Social Research Trends of the Wave P300 and More Late Components of Visual Event-Related Potentials.

To extend the application of the late waves of the event-related potentials (ERPs) to multiple modalities, devices and software the underlying physiological mechanisms and responses of the brain for a particular sensory system and mental function must be carefully examined. The objective of this study was aimed to study the sensory processes of the “human-computer interaction” model when classifying visual images with an incomplete set of signs based on the analysis of early, middle, late and slow ERPs components. 26 healthy subjects (men) aged 20–26 years were investigated. ERPs in 19 monopolar sites according to the 10/20 system were recorded. Discriminant and factor analyzes (BMDP Statistical Software) were applied. The component N450 is the most specialized indicator of the perception of unrecognizable (oddball) visual images. The amplitude of the ultra-late components N750 and N900 is also higher under conditions of presentation of the oddball image, regardless of the location of the registration points. In brain pathology along with the pronounced asymmetry of the wave distribution, reduction of the N150 wave and lengthening of its peak latency, a line of regularities were noted. These include–a pronounced reduction in peak latency P250 and N350, an increased amplitude of N350 in the frontal and central points of registration, a decrease in the amplitude of N450 in the left frontal cortex and its increase in the occipital registration points, activation of the occipital cortex at a time interval of 400–500 ms, as well as fusion later waves. We called such phenomena of the development of cognitive ERP in brain pathology “the incongruence of ERP components”. The results of the research are discussed in the light of the paradigm of the P300 wave application in brain-computer interface systems, as well as with the peculiarities in brain pathology.

The Deficit of Multimodal Perception of Congruent and Non-Congruent Fearful Expressions in Patients with Schizophrenia: The ERP Study.

Emotional dysfunction, including flat affect and emotional perception deficits, is a specific symptom of schizophrenia disorder. We used a modified multimodal odd-ball paradigm with fearful facial expressions accompanied by congruent and non-congruent emotional vocalizations (sounds of women screaming and laughing) to investigate the impairment of emotional perception and reactions to other people’s emotions in schizophrenia. We compared subjective ratings of emotional state and event-related potentials (EPPs) in response to congruent and non-congruent stimuli in patients with schizophrenia and healthy controls. The results showed the altered multimodal perception of fearful stimuli in patients with schizophrenia. The amplitude of N50 was significantly higher for non-congruent stimuli than congruent ones in the control group and did not differ in patients. The P100 and N200 amplitudes were higher in response to non-congruent stimuli in patients than in controls, implying impaired sensory gating in schizophrenia. The observed decrease of P3a and P3b amplitudes in patients could be associated with less attention, less emotional arousal, or incorrect interpretation of emotional valence, as patients differed from healthy controls in the emotion scores of non-congruent stimuli. The difficulties in identifying the incoherence of facial and audial components of emotional expression could be significant in understanding the psychopathology of schizophrenia.

Neurophysiological correlates of interference control and response inhibition processes in children and adolescents engaging in open- and closed-skill sports

BackgroundAccumulating evidence suggests that sports participation promotes the development of inhibitory control, but the influences of the sports category and inhibition type still remain unclear. The categorization of sports based on the open-skill (externally paced) and closed-skill (self-paced) continuum allows for the integration of the environment as a factor contributing to sports-related benefits for inhibitory control. MethodsCross-sectional data from different studies were combined (n = 184) to examine the association between open- and closed-skill sports and cognitive control processes related to interference control and response inhibition. Participants (aged 9−14 years) filled in 7-day physical activity recall protocols and completed a Stroop Color−Word or a Go/NoGo task. The N200, N450, and P300 components of event-related potentials elicited by these tasks were recorded using electroencephalography. ResultsPartial correlations supported the belief that time spent in open-skill sports was related to higher performance on inhibition trials. Additionally, path analyses revealed an association between this sports type and a greater negativity in the N200 and N450 amplitudes in both the full sample and group-level analyses. In contrast, no relation was found between sports type and P300 amplitude. ConclusionThe findings suggest that only the engagement in open-skill sports is associated with more effective conflict monitoring and higher performance on tasks demanding inhibitory control.

Uncoupled Brain and Behavior Changes in Lexical, Phonological, and Memory Processing in Struggling Readers

ABSTRACT Paired behavioral and ERP measures were used to track change over time in 17 third- and fourth-grade struggling readers. Word and nonword reading on standardized tests improved, but differentiation of words and letter strings, measured by N170 and N400 amplitude, did not significantly change. Sound awareness scores improved, but the ERP rhyming effect did not significantly change. Both digit span scores and latency of the P300 oddball effect decreased. Correlations between the ostensibly matched behavioral and electrophysiological measures of change were not significant, indicating that use of ERP and behavioral measures can provide nonoverlapping insight into change during reading development.

Human / Robot Distinction Recognition Using Electroencephalogram / Event-Related Potential N170

This paper presents a distinction recognition between robots by Electroencephalogram / Event-Related Potential N170 analysis. N170 is a waveform induced around 170 milliseconds after the presentation of a stimulus when a human face is presented as a stimulus. An experiment was performed on the assumption that the amplitude and time of the N170 wave change depending on the recognition of the human and the robot's face because the robot is recognized as an object rather than a human. As a result, it was confirmed that the amplitude and latency of N170 were changed by the robot. In the near future, we aim to increase the types of robots and clarify the degree of detailed recognition between humans and robots.

The efficacy of repetitive transcranial magnetic stimulation on emotional processing in apathetic patients with Parkinson's disease: A Placebo-controlled ERP study

Background: Few studies have examined the effect of rTMS on impaired emotional processing in apathetic Parkinson's disease (PD) patients, which impelled us to use a combination of repetitive transcranial magnetic stimulation (rTMS) with event-related potentials (ERPs) to gain insight into the underlying mechanisms. Methods: Apathetic and non-apathetic patients diagnosed with PD performed a facial emotion categorization task, and ERP data were collected before and after HF-rTMS or sham stimulation over the right dorsolateral prefrontal cortex (DLPFC). We observed the behavioural results and early components of P100 and N170. Results: After rTMS, accuracy (ACC) was higher for negative expressions, and reaction times (RTs) were shorter for all expressions in both apathetic and non-apathetic patients. P100 amplitudes significantly increased except for negative expressions in the right hemisphere, and hemisphere lateralization was reversed in apathetic patients. P100 amplitudes increased for all expressions bilaterally in non-apathetic patients. N170 amplitudes in apathetic patients increased, and hemisphere lateralization was normalized. Neither the apathetic sham group nor the non-apathetic cohort of patients showed changes in P100 or N170 lateralization. Limitations: The effects of rTMS on PD patients relative to normal subjects should be compared and observed over a long period of time. Conclusions: HF-rTMS over the right DLPFC is beneficial for emotional processing in both apathetic and non-apathetic PD patients but shows different sensitivities. The effect of rTMS on emotional processing impairments in apathetic PD patients is profound. Treatment with rTMS may be an important, novel nonpharmaceutical approach for apathy in PD patients.

N170 reflects orthographic uniqueness point effects in English among native Japanese and Korean readers

Orthographic uniqueness point (OUP) refers to the letter position of a word at which it is distinguishable from other lexical items in the language. Previous findings of OUP effects have been mixed and mainly demonstrated in native readers of alphabetic languages. The current study investigated whether OUP effects could be shown among non-native readers in a visual repetition detection task. The experiment tested three OUP conditions (early, mid, late) in native English readers and proficient non-native English readers whose native scripts were Japanese or Korean. Results revealed main effects of OUP on N170 amplitude, where early OUP words elicited more negative N170 and late OUP words elicited marginally less negative N170 than mean activation for both native and non-native readers. There was no indication that non-linearity or non-alphabetic nature of one’s native script influenced OUP effects. Results were consistent with a parallel letter processing account in single word reading.

Turning the Face Inversion Effect on Its Head: Violated Expectations of Orientation, Lighting, and Gravity Enhance N170 Amplitudes.

Face inversion effects occur for both behavioral and electrophysiological responses when people view faces. In EEG, inverted faces are often reported to evoke an enhanced amplitude and delayed latency of the N170 ERP. This response has been attributed to the indexing of specialized face processing mechanisms within the brain. However, inspection of the literature revealed that, although N170 is consistently delayed to a variety of face representations, only photographed faces invoke enhanced N170 amplitudes upon inversion. This suggests that the increased N170 amplitudes to inverted faces may have other origins than the inversion of the face's structure. We hypothesize that the unique N170 amplitude response to inverted photographed faces stems from multiple expectation violations, over and above structural inversion. For instance, rotating an image of a face upside-down not only violates the expectation that faces appear upright but also lifelong priors about illumination and gravity. We recorded EEG while participants viewed face stimuli (upright vs. inverted), where the faces were illuminated from above versus below, and where the models were photographed upright versus hanging upside-down. The N170 amplitudes were found to be modulated by a complex interaction between orientation, lighting, and gravity factors, with the amplitudes largest when faces consistently violated all three expectations. These results confirm our hypothesis that face inversion effects on N170 amplitudes are driven by a violation of the viewer's expectations across several parameters that characterize faces, rather than a disruption in the configurational disposition of its features.

Social Perception of Faces: Brain Imaging and Subjective Ratings.

The aim of this study was to investigate how a female face is perceived in terms of its attractiveness, dominance, health, femininity-masculinity, and maturity in direct relation to the body fat percentage (BFP) conveyed by the face. To compare how young adults (ages 18 to 35) respond to different levels of body fat percentage both subjectively and objectively we collected survey ratings and electroencephalography (EEG) data across five different levels of BFP from 40 participants. We adapted the experimental design from a prior behavioral study and used calibrated and morphed female face images of five different BFP levels. The results of the survey are in consensus with the previous study and assessed to be a successful replication. From the EEG data, event-related potentials (ERPs) were extracted from one electrode location (right occipitotemporal brain region) known to be particularly sensitive to face-stimuli. We found statistically significant differences in the amplitudes of the P200 component (194 ms post stimulus onset) between the thickest face and all four other BFP conditions, and in the amplitudes of the N300 component (274 ms post stimulus onset) between the average face and three other BFP conditions. As expected, there were no significant differences among the N170 amplitudes of all five BFP conditions since this ERP component simply reflects the processing of faces in general. From these results, we can infer that holistic face encoding characterized by the N170 component in the right occipitotemporal area is followed by serial evaluative processes, whose categorical and qualitative matrix and spatiotemporal dynamics should be further explored in future studies, especially in relation to the social constructs that were focused on in this study.

Configural processing of emotional bodies and faces in patients with attention deficit hyperactivity disorder

ABSTRACT Introduction: Attention Deficit Disorder (ADHD) is associated with interpersonal problems and difficulties in inferring other peoples’ emotions. Previous research has focused on face processing, mostly in children. Our study investigated configural processing of emotional bodies and faces in adults with ADHD in comparison with healthy controls, analyzing P100, N170 and P250 event-related potentials (ERPs) and relating them to (socio)cognitive functioning. Method: Nineteen patients with ADHD and 25 healthy controls were presented upright and inverted bodies and faces which had to be categorized as neutral, happy or angry while ERPs were recorded. Additionally, sociocognitive and executive functioning was assessed. Results: In ADHD patients relative to controls, recognition of emotions depicted by bodies but not by faces was impaired and P100 amplitudes were enhanced for angry bodies. Furthermore, patients showed enhanced P250 amplitudes in response to both bodies and faces, specifically for happy and neutral emotions. Larger N170 amplitudes to bodies and faces correlated with lower alexithymia scores only in controls, while enhanced P250 amplitudes to both categories were associated with poorer inhibition only in patients. Conclusion: Adults with ADHD show potentially compensatory enhanced semantic processing of emotional bodies and faces, as reflected by increased P250 amplitudes, associated with poorer executive functioning and subtle alterations of emotional and configural processing, as reflected by ERPs.

Emotional Facial Expression Perception and Processing in AUD Subgroups

Deficits in emotion processing among individuals with AUD are well accepted, however the potential impact of polysubstance use in this population remains uninvestigated. The current work begins to fill this gap by analyzing affective perception and processing in community controls (CCs) and two AUD subgroups differentiated by presence (Alc-Drug) or absence (Alc-Only) of polysubstance use. Behavioral task performance and electroencephalographic (EEG) indices (N170, P3) were measured for an emotion judgement task where participants classified emotional facial expressions (EFEs) morphed to 65 or 95 percent intensity. Mixed model analyses detected deficits in emotion classification accuracy among Alc-Drug relative to other groups. Although there was a main effect of emotion (greater accuracy for positive vs. negative emotions), there was no group by emotion interaction. N170 amplitude analyses found only a main effect for emotion (greater amplitude for negative vs. positive emotions). P3 amplitude analyses detected differences between control and AUD individuals, but no difference between AUD subgroups. No correlation was found between accuracy and ERP amplitudes. These findings contribute to the developing literature on emotional processing deficits in AUD, including highlighting the importance of considering polysubstance use in characterizing these deficits.

Older Adults Encode Task-Irrelevant Stimuli, but Can This Side-Effect be Useful to Them?

We studied whether, due to deteriorating inhibitory functions, older people are more likely to process irrelevant stimuli; and if so, could they later use this information better than young adults. In the study phase of our experiment, a Posner-type gaze-cued version of a Simon task was performed in which we presented task-irrelevant cues, where faces or patches with either left- or right-looking dots for the pupil of the eye preceded the task to press a button congruent or incongruent with the presentation side of the target stimulus. In the follow-up test phase, participants completed an unexpected facial recognition test. In the study phase not only a decreased P1, but also an increased N170 amplitude of the event-related potentials (ERPs) were found in older, compared to younger adults, and also for faces compared to patches. Even though in the test phase both age-groups could recognize the faces better than statistically by chance, neither the older nor the younger participants could discriminate them effectively. The late positive component (LPC)—the ERP correlates of the old/new effect, being the higher amplitude for the earlier presented stimuli when compared with the unseen stimuli during the recognition test—was not evolved in the older group, while a reversed old/new effect was seen in younger participants: higher amplitude was found in New-Right and Old-Wrong conditions (for faces they did not recognize independent of seeing them before) compared to Old-Right and New-Wrong conditions (for faces they thought they recognized from the study phase). In conclusion, although older adults showed enhanced processing of task-irrelevant stimuli compared to younger adults, as indicated by the N170 amplitude, however, they were not able to utilize this information in a later task, as was suggested by the recognition rate and LPC amplitude results.

Negativity bias towards anger in dangerous drivers: Empirical evidence from ERPs

Because of the increase in the numbers of vehicles and drivers, traffic congestion causes anger on the road to occur frequently. In addition to the impact of personality traits, the information processing of emotional stimuli also influences drivers’ behaviours. Research is needed to understand how drivers interact with anger stimuli and the differences in processing anger information between safe and dangerous drivers. This study aimed to explore the differences between safe and dangerous drivers’ negativity bias towards anger and discuss the causes of dangerous driving behaviours from the perspective of information processing. In total, 34 participants were divided into a safe group and dangerous group based on their traffic violation history and driving behaviour trends. Participants completed an emotional Stroop task with event-related potential (ERP) data. The results showed that the P200 amplitudes of dangerous drivers were significantly reduced compared with those of safe drivers when processing angry and neutral faces, indicating the inadequate assessment of angry faces in early emotional processing. The N170 amplitudes of dangerous drivers were significantly reduced compared with those of safe drivers when processing angry faces, demonstrating decreased negative input that is potentially related to dispositional fearlessness and uncaring traits. This study revealed negativity bias towards anger in dangerous drivers based on ERP evidence, enabling us to understand the differences in driving behaviours from the perspective of physiological mechanisms.

Making sense of human interaction benefits from communicative cues

We investigated whether communicative cues help observers to make sense of human interaction. We recorded EEG from an observer monitoring two individuals who were occasionally communicating with each other via either mutual eye contact and/or pointing gestures, and then jointly attending to the same object or attending to different objects that were placed on a table in front of them. The analyses were focussed on the processing of the interaction outcome (i.e. presence or absence of joint attention) and showed that its interpretation is a two-stage process, as reflected in the N300 and the N400 potentials. The N300 amplitude was reduced when the two individuals shared their focus of attention, which indicates the operation of a cognitive process that involves the relatively fast identification and evaluation of actor–object relationships. On the other hand, the N400 was insensitive to the sharing or distribution of the two individuals’ attentional focus. Interestingly, the N400 was reduced when the interaction outcome was preceded either by mutual eye contact or by a perceived pointing gesture. This shows that observation of communication “opens up” the mind to a wider range of action possibilities and thereby helps to interpret unusual outcomes of social interactions.

ERP evidence for emotional sensitivity in social anxiety

BackgroundEmotional sensitivity involves the ability to recognize and interpret facial expressions. This is very important for interpersonal communication. Previous studies found differences in emotional sensitivity between high social anxiety (HSA) individuals and low social anxiety (LSA) individuals. However, the underlying neural mechanisms are still unclear. The present study explored the effects of expression intensity and social anxiety on emotional sensitivity and their neural mechanisms. MethodsThe HSA group (n = 20) and the LSA group (n = 20) were asked to recognize anger expressions with different intensities in an emotion recognition task. The hit rate, reaction time, early time window (P1, N170), and late time window (LPP) were recorded. ResultsThe results showed that individuals with HSA had a significantly higher hit rate and shorter reaction time than individuals with LSA (p < 0.01). Event-related potential (ERP) results showed that, compared to the LSA group, the HSA group exhibited significantly enhanced N170 and LPP amplitude (p < 0.01). However, the difference in P1 amplitude was not significant (p > 0.05). LimitationsThe participants in this study were a subclinical social anxiety sample, and the effects of other mood disorders were not excluded, partially limiting the generalizability of the results. ConclusionsOur findings suggest that, compared to LSA individuals, HSA individuals are more sensitive to all presented faces. The ERP results indicated that HSA individuals’ high sensitivity to threatening expressions is related to stronger structural encoding and fine processing.