ERP evidence of visualization at early stages of visual processing

Recent neuroimaging research suggests that early visual processing circuits are activated similarly during visualization and perception but have not demonstrated that the cortical activity is similar in character. We found functional equivalency in cortical activity by recording evoked potentials while color and luminance patterns were viewed and while they were visualized with the eyes closed. Cortical responses were found to be different when imagining a color pattern vs. imagining a checkerboard luminance pattern, but the same when imagining a color pattern (or checkerboard pattern) vs. seeing the same pattern. This suggests that early visual processing stages may play a dynamic role in internal image generation, and further implies that visual imagery may modulate perception.     

ERP evidence for own-age effects on late stages of processing sad faces

Faces convey important information on interaction partners, such as their emotional state and age. Faces of the same age are, according to recent research, preferentially processed. The aim of the present study was to investigate whether the neural processes underlying this own-age effect are influenced by the emotional expression of the face, and to explore possible explanations such as the frequency or quality of contact to own-age versus other-age groups. Event-related potentials were recorded while 19 younger (18–30 years) and 19 older (64–86 years) observers watched younger and older sad and happy faces. Sad but not happy faces elicited higher late positive potential amplitudes for own-age than for other-age faces. This own-age effect was significant for older, but not for younger, observers, and correlated with the quality of contact with the own-age versus the other-age group. This pattern suggests that sad own-age faces are motivationally more relevant.     

词汇识别中歧义词素语义加工:ERP研究

结合掩蔽启动范式和ERP技术,利用歧义词素的加工,本研究探讨了歧义词素语义的激活。实验采用3×2两因素被试内设计,歧义词素两含义互为启动刺激和目标刺激,两变量分别为启动词类型(歧义词素含义1 vs.含义2 vs.无关词)和目标词类型(歧义词素含义1 vs.含义2)。行为结果发现启动词类型和目标词类型存在交互作用,即只有当共享词素同形同义的情况下,目标词的加工才可能被启动,共享词素同形不同义时并没有产生启动效应。ERP结果进一步肯定了行为结果,在N250和N400两个脑电成分上都发现了启动类型和目标类型交互作用有关的效应,当启动词和目标词共享词素同形同义时,同时引发了N250和N400的变化;当共享词素同形不同义时,时程分析时虽然也发现了N250的变化,但是N250的效应较小,小于同形同义所引发的N250效应,持续时间也较短。实验结果说明,在词汇识别中歧义词素语义可以激活,并对目标词汇加工的早期加工阶段发挥作用。     

Brain processing of task-relevant and task-irrelevant emotional words: An ERP study

Although there is evidence for preferential perceptual processing of written emotional information, the effects of attentional manipulations and the time course of affective processing require further clarification. In this study, we attempted to investigate how the emotional content of words modulates cerebral functioning (event-related potentials, ERPs) and behavior (reaction times, RTs) when the content is task-irrelevant (emotional Stroop Task, EST) or task-relevant (emotional categorization task, ECT), in a sample of healthy middle-aged women. In the EST, the RTs were longer for emotional words than for neutral words, and in the ECT, they were longer for neutral and negative words than for positive words. A principal components analysis of the ERPs identified various temporospatial factors that were differentially modified by emotional content. P2 was the first emotion-sensitive component, with enhanced factor scores for negative nouns across tasks. The N2 and late positive complex had enhanced factor scores for emotional relative to neutral information only in the ECT. The results reinforce the idea that written emotional information has a preferential processing route, both when it is task-irrelevant (producing behavioral interference) and when it is task-relevant (facilitating the categorization). After early automatic processing of the emotional content, late ERPs become more emotionally modulated as the level of attention to the valence increases.     

Effects of temporal trial-by-trial cuing on early and late stages of auditory processing: Evidence from event-related potentials

Temporal-cuing studies show faster responding to stimuli at an attended versus unattended time point. Whether the mechanisms involved in this temporal orienting of attention are located early or late in the processing stream has not been answered unequivocally. To address this question, we measured event-related potentials in two versions of an auditory temporal cuing task: Stimuli at the uncued time point either required a response (Experiment 1) or did not (Experiment 2). In both tasks, attention was oriented to the cued time point, but attention could be selectively focused on the cued time point only in Experiment 2. In both experiments, temporal orienting was associated with a late positivity in the timerange of the P3. An early enhancement in the timerange of the auditory N1 was observed only in Experiment 2. Thus, temporal attention improves auditory processing at early sensory levels only when it can be focused selectively.     

Task-dependent evaluative processing of moral and emotional content during comprehension: An ERP study

Recently, we showed that when participants passively read about moral transgressions (e.g., adultery), they implicitly engage in the evaluative (good–bad) categorization of incoming information, as indicated by a larger event-related brain potential (ERP) positivity to immoral than to moral scenarios (Leuthold, Kunkel, Mackenzie, & Filik in Social, Cognitive, and Affective Neuroscience, 10, 1021–1029, 2015). Behavioral and neuroimaging studies indicated that explicit moral tasks prioritize the semantic-cognitive analysis of incoming information but that implicit tasks, as used in Leuthold et al. (Social, Cognitive, and Affective Neuroscience, 10, 1021–1029, 2015), favor their affective processing. Therefore, it is unclear whether an affective categorization process is also involved when participants perform explicit moral judgments. Thus, in two experiments, we used similarly constructed morality and emotion materials for which their moral and emotional content had to be inferred from the context. Target sentences from negative vs. neutral emotional scenarios and from moral vs. immoral scenarios were presented using rapid serial visual presentation. In Experiment 1, participants made moral judgments for moral materials and emotional judgments for emotion materials. Negative compared to neutral emotional scenarios elicited a larger posterior ERP positivity (LPP) about 200 ms after critical word onset, whereas immoral compared to moral scenarios elicited a larger anterior negativity (500–700 ms). In Experiment 2, where the same emotional judgment to both types of materials was required, a larger LPP was triggered for both types of materials. These results accord with the view that morality scenarios trigger a semantic-cognitive analysis when participants explicitly judge the moral content of incoming linguistic information but an affective evaluation when judging their emotional content.     

An ERP investigation of regional and foreign accent processing

This study used event-related potentials (ERPs) to examine whether we employ the same normalisation mechanisms when processing words spoken with a regional accent or foreign accent. Our results showed that the Phonological Mapping Negativity (PMN) following the onset of the final word of sentences spoken with an unfamiliar regional accent was greater than for those produced in the listener’s own accent, whilst PMN for foreign accented speech was reduced. Foreign accents also resulted in a reduction in N400 amplitude when compared to both unfamiliar regional accents and the listener’s own accent, with no significant difference found between the N400 of the regional and home accents. These results suggest that regional accent related variations are normalised at the earliest stages of spoken word recognition, requiring less top-down lexical intervention than foreign accents.     

A comparison of sentence- and discourse-level semantic processing: an ERP study

Eighteen subjects listened to sentences ending with semantically congruent or incongruent words. Each congruent sentence was embedded at the end of a short story so that the final word was semantically acceptable at the sentence level but incongruent in terms of discourse context. The same stories were also presented with congruent endings. Auditory ERPs elicited by the final words in these sentences and stories were compared. Both sentence- and discourse-level semantic integration were associated with N400 and Late Positive Component (LPC) effects in addition to a new component, P550. Local and global semantic processing, although evoking the same components, were characterized by differential effects on ERP amplitudes according to the amount of text integrated and its congruence. These results indicate similar cognitive processes of context build up, underlying sentence- and discourse-semantic processing.     

The effects of stimulus complexity on the preattentive processing of self-generated and nonself voices: An ERP study

The ability to differentiate one’s own voice from the voice of somebody else plays a critical role in successful verbal self-monitoring processes and in communication. However, most of the existing studies have only focused on the sensory correlates of self-generated voice processing, whereas the effects of attentional demands and stimulus complexity on self-generated voice processing remain largely unknown. In this study, we investigated the effects of stimulus complexity on the preattentive processing of self and nonself voice stimuli. Event-related potentials (ERPs) were recorded from 17 healthy males who watched a silent movie while ignoring prerecorded self-generated (SGV) and nonself (NSV) voice stimuli, consisting of a vocalization (vocalization category condition: VCC) or of a disyllabic word (word category condition: WCC). All voice stimuli were presented as standard and deviant events in four distinct oddball sequences. The mismatch negativity (MMN) ERP component peaked earlier for NSV than for SGV stimuli. Moreover, when compared with SGV stimuli, the P3a amplitude was increased for NSV stimuli in the VCC only, whereas in the WCC no significant differences were found between the two voice types. These findings suggest differences in the time course of automatic detection of a change in voice identity. In addition, they suggest that stimulus complexity modulates the magnitude of the orienting response to SGV and NSV stimuli, extending previous findings on self-voice processing.     

Three kinds of rhymes: An ERP study

In a simple prime-target visual rhyming paradigm, pairs of words, nonwords, and single letters elicited similar event-related potential (ERP) rhyming effects in young adults. Within each condition, primes elicited contingent negative variation (CNV) while nonrhyming targets elicited more negative waveforms than rhyming targets within the 320-500ms (N400/N450) time window. The target rhyming effect, apparently primarily an index of phonological processing, was similar across conditions but tended to be smaller in mean amplitude for letters. One of the first reports of such a letter rhyming effect in the ERP literature, these findings could be important developmentally because letter rhyme tasks simultaneously index the two best predictors of ease of learning to read: letter name knowledge and phonological awareness.     

Conflict and surrender during sentence processing: an ERP study of syntax-semantics interaction

Recent ERP studies report that implausible verb-argument combinations can elicit a centro-parietal P600 effect (e.g., "The hearty meal was devouring …"; Kim & Osterhout, 2005). Such eliciting conditions do not involve outright syntactic anomaly, deviating from previous reports of P600. Kim and Osterhout (2005) attributed such P600 effects to structural reprocessing that occurs when syntactic cues fail to support a semantically attractive interpretation ('meal' as the Agent of 'devouring') and the syntactic cues are overwhelmed; the sentence is therefore perceived as syntactically ill-formed. The current study replicated such findings and also found that altering the syntactic cues in such situations of syntax-semantics conflict (e.g., "The hearty meal would devour …") affects the conflict's outcome. P600s were eliminated when sentences contained syntactic cues that required multiple morphosyntactic steps to "repair". These sentences elicited a broad, left-anterior negativity at 300-600ms (LAN). We interpret the reduction in P600 amplitude in terms of "resistance" of syntactic cues to reprocessing. We speculate that the LAN may be generated by difficulty retrieving an analysis that satisfies both syntactic and semantic cues, which results when syntactic cues are strong enough to resist opposing semantic cues. This pattern of effects is consistent with partially independent but highly interactive syntactic and semantic processing streams, which often operate collaboratively but can compete for influence over interpretation.     

Intonational phrase structure processing at different stages of syntax acquisition: ERP studies in 2-, 3-, and 6-year-old children

This study explored the electrophysiology underlying intonational phrase processing at different stages of syntax acquisition. Developmental studies suggest that children's syntactic skills advance significantly between 2 and 3 years of age. Here, children of three age groups were tested on phrase-level prosodic processing before and after this developmental phase, while their brain activity was recorded. The Closure Positive Shift (CPS), which indexes the perception of intonational phrasing in adults, served as dependent variable. The event-related brain potentials of 3- and 6-year-olds, but not of 21-month-olds, showed a CPS. These results suggest that prosodic phrase processing, as indicated by the CPS, is established only later during children's development, pointing to a close interaction of prosody and syntax acquisition.     

The influence of processing objectives on the perception of faces: An ERP study of race and gender perception

In two experiments, event-related potentials were used to examine the effects of attentional focus on the processing of race and gender cues from faces. When faces were still the focal stimuli, the processing of the faces at a level deeper than the social category by requiring a personality judgment resulted in early attention to race and gender, with race effects as early as 120 msec. This time course corresponds closely to those in past studies in which participants explicitly attended to target race and gender (Ito &Urland, 2003). However, a similar processing goal, coupled with a more complex stimulus array, delayed social category effects until 190 msec, in accord with the effects of complexity on visual attention. In addition, the N170 typically linked with structural face encoding was modulated by target race, but not by gender, when faces were perceived in a homogenous context consisting only of faces. This suggests that when basic-level distinctions between faces and nonfaces are irrelevant, the mechanism previously associated only with structural encoding can also be sensitive to features used to differentiate among faces.     

Lexical access in early stages of visual word processing: A single-trial correlational MEG study of heteronym recognition

We present an MEG study of heteronym recognition, aiming to distinguish between two theories of lexical access: the ‘early access’ theory, which entails that lexical access occurs at early (pre 200 ms) stages of processing, and the ‘late access’ theory, which interprets this early activity as orthographic word-form identification rather than genuine lexical access. A correlational analysis method was employed to examine effects of the heteronyms’ form and lexical properties on brain activity. We find support for the ‘late access’ view, in that lexical properties did not affect processing until after 300 ms, while earlier activation was primarily modulated by orthographic form.     

Iconic gestures prime related concepts: An ERP study

To assess priming by iconic gestures, we recorded EEG (at 29 scalp sites) in two experiments while adults watched short, soundless videos of spontaneously produced, cospeech iconic gestures followed by related or unrelated probe words. In Experiment 1, participants classified the relatedness between gestures and words. In Experiment 2, they attended to stimuli, and performed an incidental recognition memory test on words presented during the EEG recording session. Event-related potentials (ERPs) time-locked to the onset of probe words were measured, along with response latencies and word recognition rates. Although word relatedness did not affect reaction times or recognition rates, contextually related probe words elicited less-negative ERPs than did unrelated ones between 300 and 500 msec after stimulus onset (N400) in both experiments. These findings demonstrate sensitivity to semantic relations between iconic gestures and words in brain activity engendered during word comprehension.     

Implicit effects of emotional contexts: An ERP study

Previous recognition memory experiments have demonstrated that the ERPs elicited by correctly recognized test items differ according to whether the items were encoded in an emotionally arousing or an emotionally neutral context. It is not clear, however, whether these ERP differences depend on the explicit recognition of the items. We addressed this question in the present study by contrasting the ERPs elicited by test items encoded in emotionally negative or emotionally neutral study contexts, according to whether the items were correctly recognized or misclassified as new. Recognized items associated with emotional rather than neutral contexts elicited an early positive-going and a later negative-going effect that resembled the effects reported in prior studies. Relative to unrecognized items encoded in neutral contexts, unrecognized items encoded in emotional contexts elicited a sustained, frontal-maximum, positive-going effect that onset at about 200?ms poststimulus. This effect may reflect an influence of emotional arousal on the neural correlates of implicit memory.     

Endogenous attention modulates early selective attention in psychopathy: An ERP investigation

Psychopathic individuals are prone to act on urges without adequate consideration of future consequences or the rights of other individuals. One interpretation of this behavior is that it reflects abnormal selective attention (i.e., a failure to process information that is incongruent with their primary focus of attention; Hiatt, Schmitt, & Newman, Neuropsychology, 18, 50-59, 2004). Unfortunately, it is unclear whether this selective attention abnormality reflects top-down endogenous influences, such as the strength or specificity of attention focus (i.e., top-down set) apart from other, more exogenous (bottom-up), effects on attention. To explore this question, we used an early visual event-related potential (N2pc) in combination with a modified visual search task designed to assess the effect of early endogenous (i.e., top-down) attention on the processing of set-congruent information. The task was administered to a sample of 70 incarcerated adult males, who were assigned to high, intermediate, and low psychopathy groups using Hare’s Psychopathy Checklist-Revised (Hare, 2003). Based on the assumption that their failure to process set-incongruent information reflects the exaggerated effects of endogenous attention, we predicted that participants with high psychopathy scores would show an exaggerated N2pc response to set-congruent information. The results supported the hypothesis and provide novel electrophysiological evidence that psychopathy is associated with exaggerated endogenous attention effects during early stages of processing. Further research is needed to examine the implications of this finding for the well-established failure of psychopathic individuals to process set-incongruent information and inhibit inappropriate responses.     

Decomposing animacy reversals between agents and experiencers: An ERP study

The present study aimed to refine current hypotheses regarding thematic reversal anomalies, which have been found to elicit either N400 or - more frequently - “semantic-P600” (sP600) effects. Our goal was to investigate whether distinct ERP profiles reflect aspectual-thematic differences between Agent-Subject Verbs (ASVs; e.g., ‘to eat’) and Experiencer-Subject Verbs (ESVs; e.g., ‘to love’) in English. Inanimate subject noun phrases created reversal anomalies on both ASV and ESV. Animacy-based prominence effects and semantic association were controlled to minimize their contribution to any ERP effects. An N400 was elicited by the target verb in the ESV but not the ASV anomalies, supporting the hypothesis of a distinctive aspectual-thematic structure between ESV and ASV. Moreover, the N400 finding for English ESV shows that, in contrast to previous claims, the presence versus absence of N400s for this kind of anomaly cannot be exclusively explained in terms of typological differences across languages.     

Evidence for processing stages in skill acquisition: a dual-task study

We investigated the changes of resource demand during the acquisition of a sensorimotor skill, namely the tracking of a visual target under reversed visual feedback. This acquisition task was performed alone or concurrently with one of four manual reaction-time tasks as loading tasks, designed to tap different computational resources. As expected, we found tracking performance to deteriorate upon vision reversal and then to gradually improve with practice. We further found that acquisition task and loading task interfered little before vision reversal but substantially afterwards. Most importantly, we observed a different time-course of interference for each of our four loading tasks. The particular pattern led us to conclude that resources related to spatial attention and sensory transformations are in highest demand early during skill acquisition and those pertinent to movement preparation somewhat later. Our findings thus provide experimental support for the theory that motor learning progresses in stages characterized by different resource requirements.     

Perceptual processing at adjacent locations on a single finger: masking and response competition

When target patterns and nontarget patterns are presented either to the same or to adjacent locations on the distal pad of the index finger, the amount of interference in identifying targets depends on both the shape and the location of the nontarget (Horner, 1997). In the present study, the question of whether such interference is caused by masking (the masker in some way distorts the initial representation of the target) or by response competition (the observer mistakenly responds with the masker, rather than with the target) was investigated. A 4-to-2 paradigm was used (Craig, 1995), in which four stimuli were mapped to only two responses. Targets and nontargets were randomly selected from the set of four stimuli and presented to the same or adjacent locations on the same fingerpad. Both the distal pad and the medial pad of the index finger were tested, because innervation density varies proximodistally on the distal pad, but not on the medial pad. The results indicated that response competition was an important factor limiting perception. Furthermore, perception was affected by varying location on the distal pad, but not on the medial pad. Finally, varying location on the distal pad affected perception only when responses were based on pattern shape, not when responses were based on direction of motion. The results are discussed in terms of differences in innervation density between adjacent locations and possible resultant differences in the spatial filtering properties of the skin.