Late Positivity Research Articles

Erisipelas and its Management in a Tertiary Care Hospital

Erysipelas is an acute dermo-hypodermic (non-necrotizing) infection of bacterial origin, mainly group A beta-hemolytic streptococcus. The lower limbs are affected in more than 80% of cases and the risk factors identified are skin barrier breakdown, lymphedema and obesity. Diagnosis is clinical and is based on the association of an acute inflammatory plaque with fever, lymphangitis, lymphadenopathy and leukocytosis. Bacteriology is generally not useful due to low sensitivity or late positivity. In atypical forms, erysipelas should be distinguished from necrotizing fasciitis and acute venous thrombosis. Penicillin remains the gold standard treatment, although new drugs may be used, given their pharmacodynamic profile. Recurrence is the main complication, being crucial the correct treatment of risk factors1.

The role of selective attention in Chinese emotional word processing: evidence from event-related potentials.

This study seeks to explore the interaction between ignored valence and attended valence in the processing of Chinese emotion words. The experimental materials utilized in this study consisted of Chinese emotion words. Participants were instructed to observe the words and press a key when presented with target words. Additionally, the electroencephalographic responses of the participants were recorded during the experiment. The results showed that emotional nontarget words elicited greater amplitude of the N170 in the attend-emotion words block compared to the attend-neutral words block. Negative nontarget words produce greater amplitude of the late posterior positivity compared to positive nontarget words. In addition, emotional nontarget words were influenced by both ignored and attended valence, whereby positive nontarget words resulted in larger amplitude of the N170 component in the attend-negative block compared to the attend-neutral block. The modulation pattern for negative nontarget words was evident on the left hemisphere. The findings suggest that emotional nontarget words received greater attentional resources in the attend-emotion words block during the early stages of processing, compared to the attend-neutral word block. Additionally, during the later stages of processing, negative nontarget words were more likely to be processed than positive nontarget words. Overall, these results provide support for the evaluation space model.

The cognitive control mechanism of improving emotion regulation: A high-definition tDCS and ERP study

BackgroundCognitive reappraisal as a commonly used emotion regulation strategy includes reinterpretation and detachment and is associated with the activity of the dorsolateral prefrontal cortex (DLPFC). However, the neuroenhancement mechanisms of transcranial direct current stimulation (tDCS) over DLPFC that modulate cognitive reappraisal are not yet fully understood. This work aims to verify the causal role of DLPFC in different tactics of cognitive reappraisal and further explore the cognitive control mechanisms of emotion regulation. MethodsA single-blind, within-subjects, sham-controlled design was adopted. Twenty-nine healthy subjects underwent two sessions of offline high-definition tDCS (HD-tDCS) that were targeted at the right DLPFC. Participants completed the cognitive control (Flanker) and cognitive reappraisal task in each session. We quantified the efficacy of cognitive control using N2 and P3 of the evoked brain responses and cognitive reappraisal using the late positivity potential (LPP). ResultsAnodal HD-tDCS resulted in the decrease of LPP for reinterpretation and detachment. The cognitive control increased after stimulation, indicated by the increase of P3 and decrease of N2 amplitude. The increased cognitive control mediated the effect of HD-tDCS on modulating reinterpretation, but not for detachment. LimitationsThe single-blind design, absence of the lasting-effects measure, and the intrinsically limited focality of tDCS are limitations of this study. ConclusionsIncreasing the activity of DLPFC would facilitate emotion regulation and increase cognitive control. Cognitive control may be a significant potential mechanism for reinterpretation. Both tDCS and cognitive control interventions may be possible approaches to enhance emotion regulation.

What naturalistic stimuli tell us about pronoun resolution in real-time processing.

Studies on pronoun resolution have mostly utilized short texts consisting of a context and a target sentence. In the current study we presented participants with nine chapters of an audio book while recording their EEG to investigate the real-time resolution of personal and demonstrative pronouns in a more naturalistic setting. The annotation of the features of the pronouns and their antecedents registered a surprising pattern: demonstrative pronouns showed an interpretive preference for subject/agent antecedents, although they are described to have an anti-subject or anti-agent preference. Given the presence of perspectival centers in the audio book, this however confirmed proposals that demonstrative pronouns are sensitive to perspectival centers. The ERP results revealed a biphasic N400-Late Positivity pattern at posterior electrodes for the demonstrative pronoun relative to the personal pronoun, thereby confirming previous findings with highly controlled stimuli. We take the observed N400 for the demonstrative pronoun as an indication for more demanding processing costs that occur due to the relative unexpectedness of this referential expression. The Late Positivity is taken to reflect the consequences of attentional reorientation: since the demonstrative pronoun indicates a possible shift in the discourse structure, it induces updating of the discourse structure. In addition to the biphasic pattern, the data showed an enhanced positivity at frontal electrode sites for the demonstrative pronoun relative to the personal pronoun. We suggest that this frontal positivity reflects self-relevant engagement and identification with the perspective holder. Our study suggests that by using naturalistic stimuli, we get one step closer to understanding the implementation of language processing in the brain during real life language processing.

Neural correlates of conscious processing of emotional faces: Evidence from event-related potentials

There is a theoretical debate between the early and late neural correlates of consciousness (NCCs). Previous studies using neutral face stimuli supported an early NCC and suggested that visual awareness negativity (VAN) is associated with consciousness, while late positivity (LP) reflects post-perceptual activity. However, emotional faces may help to examine the relationship between LP and consciousness due to the differences in late processing between emotional and neutral faces. To explore the effects of facial emotional information on NCCs, the present study manipulated consciousness with the inattentional blindness paradigm and used happy, fearful, and neutral faces as visual stimuli. The results showed that the conscious processing of emotional faces was correlated with VAN and LP, while the conscious processing of neutral faces was associated with VAN. First, the results suggest that VAN is an NCC, and the relationship between LP and consciousness is affected by facial emotional information. Second, VAN reflects the early perceptual experience of emotional faces, whereas LP may reflect the late conscious processing of emotional faces. Furthermore, source localization analysis showed that the LPs of emotional faces were mainly located in the frontal and parietal lobes, whereas those of neutral faces showed no significant activation. This suggests that facial emotional information may affect the brain regions associated with conscious processing. Time–frequency analysis showed that conscious processing is related to the enhancement of alpha and theta oscillation, indicating that conscious processing may be associated with the suppression of irrelevant stimuli. Overall, the present study suggests that the integration of the theories that support early and late NCCs helps explain the conscious processing of emotional faces.

Age-related differences in ERP correlates of value-based decision making

This study evaluates age-related differences in the temporal dynamics underlying neural processing of value for decision-making in younger and older adults. We applied a lottery-choice task with event-related potentials to determine how and when brain activity during choice and outcome processing diverge between younger and older adults. Behaviorally, older adults accepted more losing stakes than younger adults. During choice, younger adults evinced higher P2 ERP-response positivity with a later P3 positivity that monotonically increased with low to middle to high win probability. Older adults evinced lower P2 responses and P3 amplitudes with more positivity for high and low relative to middle win probability. Both age groups showed similar feedback-related negativity and late parietal positivity, indicating intact reward prediction error representations and salience integration. Feedback-P3 showed more complex sensitivity to expectancy violations in older than younger adults, suggesting subjective uncertainty about reward expectations. Reduced early general neural processing of objective stimulus value with greater contribution of downstream subjective processes might underlie older adult risk-taking behaviors.

Alpha Suppression Is Associated with the Tip-of-the-Tongue (TOT) State Whereas Alpha Expression Is Associated with Knowing That One Does Not Know.

The tip-of-the-tongue (TOT) state is a spontaneously occurring metacognitive state that indicates that the answer to a query is almost, but not quite, at hand, i.e., that resolution is imminent. Since the time of William James, a distinctive feeling of nagging frustration has been observed to be associated with TOT states. On a more positive note, TOT states are also associated with intense goal-directed curiosity and with a strong desire to know that translates into successful mental action. The present study showed that prior to the presentation of resolving feedback to verbal queries-if the individual was in a TOT state-alpha suppression was in evidence in the EEG. This alpha suppression appears to be a marker of a spontaneously occurring, conscious, and highly motivating goal-directed internal metacognitive state. At the same time, alpha expression in the same time period was associated with the feeling of not knowing, indicating a more discursive state. Both alpha and alpha suppression were observed broadly across centro-parietal scalp electrodes and disappeared immediately upon presentation of the resolving feedback. Analyses indicated that the occurrence of alpha suppression was associated with participants' verbal affirmations of being in a TOT state, which is also related to subsequent expression of a late positivity when feedback is provided, and to enhanced memory.

Electrophysiological evidence for a subject-first strategy in visually situated auditory sentence processing in Korean

This study investigated a subject-first strategy in prediction mechanism in visually situated sentence processing in Korean, using event-related potentials (ERPs). According to the subject-first strategy, parsers tend to generate sentences conforming to canonical sentence word order (i.e., SOV in Korean), subject-first sentence, mapping conceptually more prominent referent such as agent of the event on the subject position of the sentence. Therefore, in the predictive mechanism of language comprehension, the subject is pre-activated and anticipated for the first NP of the sentence at the initial phase of bottom-up language processing. This study tested this subject-first strategy in Korean by examining brain responses to object-initial sentences (OV) compared with subject-initial sentences (SV) under the context of clear thematic role relations set by a visual image. The results of an ERP experiment with 30 native Korean speakers identified neural effects for object-initial sentences compared with subject-initial sentences at the NP and Verb, reflecting a conflict between the pre-activated representation in the parser's mind and the encountered bottom-up input. An N400 effect was elicited at the NP, as early as at the noun, not at the following object case marker. Late frontal positivity (LFP) was also found in the sentence-final verb, proving the processing difficulty of non-canonical object-initial sentences compared with canonical subject-initial sentences. These results indicate that Korean native speakers build linguistic representation conforming to a canonical sentence in SOV language in the predictive mechanism supporting subject-first strategy but revise the predicted event structure rapidly upon newly encountering input.

Affective touch during the processing of angry facial expressions: an event-related potential study

It has been shown that affective touch can have stress-buffering effects. The current event-related potential (ERP) study investigated whether affective touch can reduce emotional distress and associated late positivity while viewing angry facial expressions. A total of 122 females (mean age = 23 years) were randomly assigned to one of three groups to either receive slow/soft brushing of their forearm (affective touch), fast brushing (nonaffective touch), or no touch while viewing images depicting angry and neutral facial expressions. The participants rated their affective state (valence, arousal) before and after the experiment. They also rated the perceived intensity of the angry facial expressions and the pleasantness of touch during the experiment. Components of the Late Positive Potential (LPP) in response to the images that are associated with stimulus significance, attention allocation, and emotion regulation (early LPP: 400–1000 ms; late LPP: 1000–3000 ms) were extracted for a frontal and a centroparietal cluster. Affective touch was associated with reduced amplitudes of the late LPP in the frontal cluster but did not affect centroparietal LPPs (early, late). Affective touch was rated as more pleasant than nonaffective touch but did not change reported valence, arousal, and perceived anger intensity. In conclusion, affective touch modulated a neural indicator of stimulus significance but did not influence self-report measures. More naturalistic touch settings might enhance the effects.

Different ways to forget: Electrophysiological mechanisms underlying item-method directed forgetting of angry and neutral faces.

Emotional stimuli, including faces, receive preferential processing and are consequently better remembered than neutral stimuli. Therefore, they may also be more resistant to intentional forgetting. The present study investigates the behavioral and electrophysiological consequences of instructions to selectively remember or forget angry and neutral faces. In an item-method directed forgetting experiment, angry and neutral faces were randomly presented to 25 student participants (4 males). Each face was followed by an instruction to either forget or remember it and the participants’ EEG was recorded. Later, recognition memory was unexpectedly tested for all items. Behaviorally, both hit and false alarm rates were higher for angry alike than for neutral faces. Directed forgetting occurred for neutral and angry faces as reflected in a reduction of both recognition accuracy and response bias. Event-related potentials revealed a larger late positive potential (LPP, 450 – 700 ms) for angry than for neutral faces during face presentation and, in line with selective rehearsal of remember items, a larger LPP following remember than forget cues. Forget cues generally elicited a larger frontal N2 (280 – 400 ms) than remember cues, in line with the forget instruction eliciting conflict monitoring and inhibition. Selectively following angry faces, a larger cue-evoked P2 (180 – 280 ms) was observed. Notably, forget cues following angry faces elicited a larger late frontal positivity (450 - 700 ms) potentially signaling conflict resolution. Thus, whereas both angry and neutral faces are subject to directed forgetting, on a neural level, different mechanisms underlie the effect. While directed forgetting for neutral faces may be achieved primarily by selective rehearsal, directed forgetting of angry faces involves an additional late frontal positivity, likely reflecting higher cognitive demands imposed by forgetting angry faces.

Evoking the N400 Event-related Potential (ERP) Component Using a Publicly Available Novel Set of Sentences with Semantically Incongruent or Congruent Eggplants (Endings)

During speech comprehension, the ongoing context of a sentence is used to predict sentence outcome by limiting subsequent word likelihood. Neurophysiologically, violations of context-dependent predictions result in amplitude modulations of the N400 event-related potential (ERP) component. While the N400 is widely used to measure semantic processing and integration, no publicly-available auditory stimulus set is available to standardize approaches across the field. Here, we developed an auditory stimulus set of 442 sentences that utilized the semantic anomaly paradigm, measured cloze probability for all stimuli, and was made for both children and adults. With 20 neurotypical adults, we validated that this set elicits robust N400′s, as well as two additional semantically-related ERP components: the recognition potential (∼ 250 ms) and the late positivity component (∼ 600 ms). This stimulus set (https://doi.org/10.5061/dryad.9ghx3ffkg) and the 20 high-density (128-channel) electrophysiological datasets (https://doi.org/10.5061/dryad.6wwpzgmx4) are made publicly available to promote data sharing and reuse. Future studies that use this stimulus set to investigate sentential semantic comprehension in both control and clinical populations may benefit from the increased comparability and reproducibility within this field of research.

Emotional Attractors in Subject-Verb Number Agreement.

Considering the crosstalk between brain networks that contain linguistic and emotional information and that no studies have examined the impact of semantic information of affective nature on subject-verb number agreement, the present Event Related Potential (ERP) study investigated the extent to which emotional local nouns whose number mismatched that of subject head nouns might be considered by the parser during comprehension of grammatically correct sentences. To this end, twenty-eight Spanish native speakers were tested on a self-paced reading task while their brain activity was recorded. The experimental materials consisted of 120 sentences where the valence (negative vs. neutral) and number (singular vs. plural) of the local noun of the singular subject noun-phrase (NP) were manipulated; El gorro de aquel/aquellos cazador(es)/mecánico(s) era… [The hat of that/those hunter(s)/mechanic(s) was…]. ERP results measured in the local noun position showed that valence and number interacted in the 300–500 ms (negative component) and 780–880 ms (late positivity) time windows. In the (target) verb position, the two factors only interacted in the late 780–880 ms time window, revealing an “ungrammatical illusion” for plural marked neutral words. Our findings suggest that number agreement is sensitive to affective meaning but that the emotional information of an attractor is considered in different operations and at different stages during grammatical sentence processing; it can affect lexical and syntactic representation retrieval of a subject-NP and impact agreement encoding only at late stages of processing, during verb agreement and feature integration.

Can't stop thinking: The role of cognitive control in suppression-induced forgetting

The ability to control unwanted memories is essential for emotional regulation and maintaining mental health. Previous evidence indicates that suppressing retrieval, which recruits executive control mechanisms to prevent unwanted memories entering consciousness, can cause forgetting, termed suppression-induced forgetting (SIF). Since these executive mechanisms involve multiple mental operations, we hypothesize that the efficacy of SIF may be limited by individuals’ capacity limitation of cognitive control. Here, we tested this hypothesis. Participants were assigned to two groups based on the median of their cognitive control capacity (CCC, estimated by the backward masking majority function task) and performed the think/no-think task with electrophysiological signals recorded. The results showed that the SIF effect was observed only in the high CCC group but not in the low CCC group. In accordance, repeated suppression attempts also resulted in a steeper reduction in intrusive thoughts in the high CCC group. Furthermore, ERP analysis revealed a decrease in recollection-related late parietal positivity (LPP) under the no-think condition in the high CCC group. A mediation analysis revealed that the reduced intrusive memories mediated the effect of CCC on SIF. These findings suggest that suppressing retrieval could reduce traces of the unwanted memories, making them less intrusive and harder to recall. More importantly, successful SIF is constrained by the capacity of cognitive control which may be used to ensure the coordination of multiple cognitive processes during suppression.

Child sex differences in the auditory equiprobable Go/NoGo task

Our previous studies of the equiprobable auditory Go/NoGo task have been used to substantiate a perceptual/cognitive Processing Schema in young and older adults, and in children. The processes in the Schema are linked to PCA components derived separately from Go and NoGo ERPs. Here we investigated sex differences in the child Schema. Two groups of fourteen children (aged 8 to 13 years) were individually matched on age and presented with four stimulus blocks of the equiprobable Go/NoGo task, each containing 75 NoGo and 75 Go tones in random order. Separate NoGo and Go ERPs were obtained from each child and submitted to temporal Principal Components Analyses (PCAs). Each ERP was analysed in two epochs (−100–400 ms and 300–800 ms) to improve the cases:variables ratio. Four pairs of temporal PCAs, each with unrestricted VARIMAX rotation, separately quantified the NoGo and Go ERPs of each epoch in each group. After these pairs were combined in temporal order, four sets of similar components were extracted. Many identified components were differentially enhanced to either NoGo or Go, as in previous work with children. The Female group had NoGo component latencies that were systematically some 3.5% greater than in Males, but there were no sex differences in Go latencies. Females also displayed fewer NoGo commission and Go omission errors, and faster Go RT than Males. Females had larger NoGo N2b, and larger Go components from N2b through to the late positivity. These results, including their ERP component/behaviour correlations, can be integrated as a task-specific behavioural and ERP processing enhancement in girls that suggests their developmental advantage over boys in this age range.

Minding the manner: attention to motion events in Turkish–Dutch early bilinguals

AbstractLanguages differ in the way motion events are encoded. In satellite-framed languages, motion verbs typically encode manner, while in verb-framed languages, path. We investigated the ways in which satellite-framed Dutch and verb-framed Turkish co-determine one’s attention to motion events in early bilinguals. In an EEG oddball paradigm, Turkish–Dutch bilinguals (n = 25) and Dutch controls (n = 27) watched short video clips of motion events, followed by a still picture that matched the preceding video in four ways (oddball design: 10% full match, 10% manner match, 10% endpoint match, and 70% full mismatch). We found that both groups showed similar oddball P300 effects, associated with task-related attention. Group differences were revealed in a late positivity (LP): The endpoint-match elicited a larger LP than the manner-match in the bilinguals, which may reflect language-driven attention. Our results indicate that cross-linguistic manner encoding difference impacts attention at a later stage.

Motor Compatibility Effect on the Comprehension of Complex Manual Action Sentences in L2: An ERP Study

Abstract Embodiment theories proposed that the comprehension of language involves sensory-motor simulation in the brain. The present study examined the brain response to motor compatibility effect in comprehending action-related linguistic materials for participants learning Chinese as a second language (L2). In this study, participants are required to read action-related sentences describing an agent performing two manual actions simultaneously or sequentially by manipulating temporal conjunctions. The sentences with simultaneous actions are marked by Chinese parallel structure 一边……一边…… (“while”) showing non-congruent motor condition while the sequential action sentences are marked by 先……然后…… (“after”) showing congruent motor condition. Event-Related Potentials (ERPs) were recorded with the second verb phrase. A larger fronto-central late positivity was observed for the sentences with simultaneous actions rather than the sentences with sequential actions due to body constraints, revealing that late L2 Chinese learners integrate embodied knowledge while processing action-related complex sentence despite demanding more cognitive resources, and longer processing time.

The relationship between acoustic and musical pitch processing in adolescents.

Amusia is defined as a difficulty processing the tonal pitch structure of music such that an individual cannot tell the difference between notes that are in-key and out-of-key. A fine-grained pitch discrimination deficit is often observed in people with amusia. It is possible that an intervention, early in development, could mitigate amusia; however, one challenge identifying amusia early in development is that identifying in- and out-of-key notes is a metacognitive task. Given the common co-occurrence of difficulties with pitch discrimination, it would be easier to identify amusia in developing children by using a pitch change detection task. The goal of this study was to explore the behavioural and neurophysiological profiles of adolescents with poor pitch processing (Poor PP) abilities compared with those with normal pitch processing (Normal PP) abilities. Neurophysiologically, the Poor PPs exhibited a similar event-related potential (ERP) profile to adult amusics during both acoustic and musical pitch discrimination tasks. That is, early ERPs (ERAN, MMN) were similar in Poor PPs compared with Normal PPs, whereas late positivities (P300, P600) were absent in Poor PPs, but present in Normal PPs. At the same time, behavioural data revealed a double dissociation between the abilities to detect a pitch deviant in acoustic and musical context, suggesting that about a third of the children would be missed by selecting a fine-grained acoustic pitch discrimination task to identify the presence of amusia in early childhood.

Encoding in a social feedback context enhances and biases behavioral and electrophysiological correlates of long-term recognition memory

Encoding often occurs in social contexts, yet research has hardly addressed their role in verbal memory. In three experiments, we investigated the behavioral and neural effects of encoding context on memory for positive, negative, and neutral adjectives, contrasting a social-feedback group (N = 24) with an explicit verbal-learning (N = 24) and a levels-of-processing group (N = 24). Participants in the social-feedback group were not aware of a recognition session one week later, but their memory was better than the explicit learning or the levels-of-processing groups'. However, they also exhibited the strongest response bias, particularly for positive words. Brain event-related potentials (ERPs) revealed largest early negativities (EPN) and late positivities (LPP) in the social-feedback group. Only in the subsequent slow-wave did the explicit learning group show higher amplitudes than the other two groups, suggesting reliance on strategic rather than automatic processes. Still, context-driven incidental encoding outweighed explicit instructions, specifying a decisive role of social factors in memory.

The cognitive processing of tone sandhi in different information structural status during dialogue comprehension

ABSTRACT Mandarin tone 3 (T3) sandhi is a phonological alternation where a T3 changes to a rising tone when followed by another T3. The present event-related potential (ERP) study examined how sandhi words are processed during dialogue comprehension. Following different wh-questions, the answers embedded a sandhi word in which the first syllable was either pronounced as post-sandhi T3, pre-sandhi T3, or mispronounced T4 at the focus or background position. The results showed that the naturalness rating decreased as the amplitude of a late positivity (LPC) increased in the order of post-sandhi, pre-sandhi, and mispronunciation conditions, reflecting a reanalysis process after encountering the unexpected tone. At the background (vs. focus) position, the effect was more posterior for the mispronunciation condition, and disappeared for the pre-sandhi condition. Our data suggest that the processing of sandhi words is not only influenced by their tonal realisation, but also moderated by their information structural status.

How accentuation influences the processing of emotional words in spoken language: An ERP study

Pitch accent marks information structure in utterances in many languages but little is known about the effects of accent on the perception of emotional word meaning. The present study explored the processing of accentuation and its influence on the semantic integration of emotional words during spoken sentence comprehension. Twenty-five participants were presented with sets of spoken Chinese sentences while accentuation and emotional meaning of the adjectives were orthogonally manipulated. An implicit task required the recognition of words contained in the sentences, whereas an explicit task required judging the presence of an accented or emotional word. In the ERPs to the adjectives, accentuation induced a long-lasting anterior negativity starting around 150–250 ms and a late posterior positivity. More importantly, emotionally negative words elicited larger negativities between 300 and 700 ms as compared to neutral words but only when they were accented. Interestingly, these negativities showed a parietal N400-typical distribution when accent was implicit but strongly overlapped with the accent-induced anterior negativity when accent was task-relevant. Hence, accentuation may enable the processing of emotional meaning by directing attention towards the accented words. When accent and emotion are explicit parts of the task, similar frontal attentional networks are activated by emotion as by accent alone. In contrast, when accent and emotion are implicit to the task, emotion appears to merely activate parietal networks, typical for semantic integration effects. Together, these results suggest that accentuation plays an important role in spoken sentence comprehension, deserving further study.