Effects of semantic discrimination of Chinese words on N400 component of event-related potentials.

20 subjects' event-related brain potentials were measured during a lexical decision task in which Chinese characters were used in both conditions of related (antonym) and unrelated words. Analysis indicated that the mean reaction time for unrelated words was 130 msec. longer than that elicited by related words. The condition of unrelated words elicited a significant N450, and an obvious P500 was evoked by related words at each of the 17 recording sites. Furthermore, the amplitudes of N210 and N450 were larger in the left hemisphere than in the right hemisphere but the amplitude of P500 was larger in the right hemisphere than in the left hemisphere.     

Hemispheric predominance assessment of phonology and semantics: a divided visual field experiment

The aim of the present behavioural experiment was to evaluate the most lateralized among two phonological (phoneme vs. rhyme detection) and the most lateralized among two semantic ("living" vs. "edible" categorization) tasks, within the dominant hemisphere for language. The reason of addressing this question was a practical one: to evaluate the degree of the hemispheric lateralization for several language tasks, by using the divided visual presentation of stimuli, and then choose the most lateralized semantic and phonological for mapping language in patients by using fMRI in future studies. During the divided visual field experiment by using words (semantic tasks) and pseudo-words (phonological tasks) as stimuli, thirty-nine right-handed participants were examined. Our results have shown that all tasks were significantly left hemisphere lateralized. Furthermore, the rhyme was significantly more lateralized than phoneme detection and "living" was significantly more lateralized than "edible" categorization. The rhyme decision and "living" categorization will be used in future fMRI studies for assessing hemispheric predominance and cerebral substrate for semantics and phonology in patients. Our results also suggest that the characteristics of stimuli could influence the degree of the hemispheric lateralization (i.e., the emotional charge of stimuli for words and the position of the phoneme to be detected, for pseudo-words).     

Emotional face prediction in rejection sensitive individuals: Evidence from event-related potentials

Human beings live in an uncertain world, but they continuously generate top-down predictions about emotional face information of other people around them. Although the prediction processing has repeatedly been investigated in the literature of prediction, little is known about the impact of rejection sensitive (RS) on individuals’ emotional face prediction. To this end, high and low RS participants were asked to perform an identification task of emotional faces in which target faces were shown in either an angry or happy expression while their brain responses were recorded using an event-related potential (ERP) technique. The behavioral results suggested an effect of emotional face prediction. For the P100 component, low RS participants showed longer P100 peak latencies in the left than right hemisphere when they viewed predictable emotional faces. In addition, low RS participants showed larger N170 mean amplitudes for angry compared to happy faces when they perceived unpredictable faces, but not when these faces were predictable. This presumably reflected a sensibility to angry faces in the unpredictable trails. Interestingly, high RS participants did not demonstrate such a N170 difference, suggesting that high RS participants showed a reduced sensitivity to unpredictable angry faces. Furthermore, angry faces triggered increased LPP mean amplitudes compared to happy faces, which was consistent with the results of other ERP studies examining the processing of emotional faces. Finally, we observed significant negative correlations between behavioral and ERP prediction effect, indicating one consistency between the behavioral and electrophysiological data.     

词汇具体性对情绪名词效价加工影响的ERP研究

具体性和抽象性是词汇同一特性的两极, 是直接影响词汇加工过程的重要因素。本研究采用快速序列视觉呈现范式, 结合脑电技术探讨在有限注意资源内, 词汇具体性对情绪名词加工过程的影响。结果发现：名词加工早期和晚期阶段的ERP成分受到情绪效价的调节, 情绪词比中性词诱发了更大的N170和LPC波幅; 名词加工早期和晚期阶段的ERP成分也受到词汇具体性的调节, 具体词比抽象词诱发了更大的N170和LPC波幅; 词汇具体性影响情绪名词加工的晚期阶段, LPC波幅能够分辨出不同情绪效价的抽象词, 对于具体词仅能区分出情绪与非情绪, 这说明抽象词可能比具体词负载了更多的情绪信息, 反映出对情绪信息的精细加工过程。     

Lateralization of lexical codes in auditory word recognition

Three experiments examined the lateralization of lexical codes in auditory word recognition. In Experiment 1 a word rhyming with a binaurally presented cue word was detected faster when the cue and target were spelled similarly than when they were spelled differently. This orthography effect was larger when the target was presented to the right ear than when it was presented to the left ear. Experiment 2 replicated the interaction between ear of presentation and orthography effect when the cue and target were spoken in different voices. In Experiment 3, subjects made lexical decisions to pairs of stimuli presented to the left or the right ear. Lexical decision times and the amount of facilitation which obtained when the target stimuli were semantically related words did not differ as a function of ear of presentation. The results suggest that the semantic, phonological, and orthographic codes for a word are represented in each hemisphere; however, orthographic and phonological representations are integrated only in the left hemisphere.     

Evidence for right hemisphere phonology in a backward masking task

The extent to which orthographic and phonological processes are available during the initial moments of word recognition within each hemisphere is under specified, particularly for the right hemisphere. Few studies have investigated whether each hemisphere uses orthography and phonology under constraints that restrict the viewing time of words and reduce overt phonological demands. The current study used backward masking in the divided visual field paradigm to explore hemisphere differences in the availability of orthographic and phonological word recognition processes. A 20 ms and 60 ms SOA were used to track the time course of how these processes develop during pre-lexical moments of word recognition. Nonword masks varied in similarity to the target words such that there were four types: orthographically and phonologically similar, orthographically but not phonologically similar, phonologically but not orthographically similar and unrelated. The results showed the left hemisphere has access to both orthography and phonology early in the word recognition process. With more time to process the stimulus, the left hemisphere is able to use phonology which benefits word recognition to a larger extent than orthography. The right hemisphere also demonstrates access to both orthography and phonology in the initial moments of word recognition, however, orthographic similarity improves word recognition to a greater extent than phonological similarity.     

Timing characteristics of speech after brain damage: vowel length in Thai.

This paper explores the extent of timing deficits in vowels produced by brain-damaged speakers of a language with a phonological contrast in vowel length. Short and long vowels in Thai were produced in isolated monosyllabic words by 20 normal adults, 14 right hemisphere patients, and 17 left hemisphere aphasics. Vowel durations were measured spectrographically. Although the phonological contrast was relatively preserved, as indicated by average duration, a subtle timing deficit in vowels produced by nonfluent aphasics was indicated by a compressed duration continuum and increased variability in vowel production.     

Reaction times and evoked potentials as indicators of hemispheric differences for laterally presented name and physical matches

Letter pairs, which could be name matches, physical matches, or mismatches, were presented at fixation or 2.5 degrees left or right of fixation. During different experimental sessions, the locations and the types of matches were fixed (and therefore known in advance by the subject) or were randomized. Right visual field superiority in reaction time occurred for name matches only when location was randomized, and then the extent of the superiority depended on whether the types of match called for were predictable. Evoked potentials to the letter pairs during this task revealed hemispheric and neural pathway differences that were independent of expectancy condition. Right hemisphere responses were larger than left. For some components, amplitudes were smaller and latencies were shorter for direct than for indirect projection of stimuli to each cerebral hemisphere. Indirect-direct differences in P300 amplitude varied for each cerebral hemisphere according to whether a physical or name match occurred. The P130 and N170 components manifested hemispheric differences that depended on whether the two letters of a pair were in the same or different cases.     

Effects of visual-field and matching instruction on event-related potentials and reaction time

Vertical letter pairs were presented randomly in the left and right visual hemifields in a physical identity match and name identity match condition. The reaction times showed a right visual field superiority for name matches, and a left visual field superiority for physical matches. Event-related potentials to letter pairs showed a sequence of three waves: a negative wave (N2, around 270 msec), a positive wave (P3, around 500 msec), and a broad positive slow wave (SW, around 600-700 msec), respectively. P3 and SW amplitudes were consistently larger at the left hemisphere than at the right hemisphere, regardless of the field of stimulation. At both hemispheres, N2 waves were always larger to stimuli presented in the visual field contralateral to a hemisphere than stimuli presented in the visual field ipsilateral to a hemisphere. The positive waves (P3, SW) showed the opposite pattern: smaller amplitudes to stimuli that were presented contralaterally than stimuli that were presented ipsilaterally to a given hemisphere. These results were attributed to a shift in sustained negativity on the directly stimulated hemisphere, relative to the indirectly stimulated hemisphere, reflecting either sensory at attentional processes in the posterior cerebral hemispheres.     

Visual field differences in the processing of numerical stimuli

Twenty-four right-handed subjects received random presentations of the numbers 1-6 in the form of words, digits, and dot patterns, to the left and right visual fields. Accuracy and reaction time were recorded for an odd-even judgment requiring a manual response. A significant stimulus type of visual field interaction was obtained, with words showing a left-hemisphere advantage and digits and dot patterns showing a right-hemisphere advantage. This pattern supports Coltheart's (1980, Deep dyslexia: A right hemisphere hypothesis, In M. Coltheart, K. Patterson, & J.C. Marshall (Eds.), Deep dyslexia, London: Routledge & Kegan Paul) right hemisphere reading hypothesis, which suggests that the left hemisphere's general advantage in processing linguistic material may be specific to stimuli which involve phonological processing. When phonological processing is not possible (e.g., for arabic digits and other ideographic orthographies), the right hemisphere may have an advantage because of its superior visuospatial processing capabilities.     

Lateral asymmetry in phonological processing: relating behavioral measures to neuroimaged structures

Recent neuroimaging studies have revealed neuroanatomical centers of activation that appear to be linked specifically to phonological processes. Furthermore, there is evidence that these centers of activation are more likely to be bilaterally represented in women than in men. However, behavioral evidence of such hemispheric asymmetries or of related sex differences is somewhat inconsistent. Two experiments were carried out to determine whether behavioral correlates of the neuroimaging findings could be demonstrated. The first experiment employed a rhyme-matching task used in a recent neuroimaging study, in which two nonsense words were projected successively to the left or right sides of the visual field. The results indicated that the left hemisphere was superior for this task. An analysis of gender effects, however, revealed that the asymmetry was restricted to men. The second experiment employed a lateralized pseudohomophone detection task that was designed to determine whether the results of the first experiment could be confirmed in the context of a phonological task with a simpler structure. This experiment broadly supported the findings of the first experiment. The results support the specialization of the left hemisphere for phonological processing, and the existence of gender differences with respect to these processes.     

When phonology fails: orthographic neighbourhood effects in dyslexia

Both cerebral hemispheres contain phonological, orthographic and semantic representations of words, however there are between-hemisphere differences in the relative engagement and specialization of the different representations. Taking orthographic processing for example, previous studies suggest that orthographic neighbourhood size (N) has facilitatory effects in the right but not the left hemispheres. To pursue the nature of this asymmetric N effect, in particular whether there are individual differences in such specialisation, we examined N in a case of developmental dyslexia, FM. We first describe the nature of his difficulties, which are mainly severe phonological deficits. Employing the divided visual field paradigm with FM revealed a greater sensitivity in the right than in the left hemisphere to orthographic variables, with a significant inhibitory N effect in the left, but not right hemisphere. Such inhibition, to a lesser degree, was found among a group of adults with dyslexia but not among age-matched normal readers. We argue that enhanced sensitivity to orthographic cues is developed in some cases of dyslexia when a normal, phonology-based left hemisphere word recognition processing is not achieved. The interpretation presented here is cast in terms of differences between people with dyslexia and typical readers that originate in the atypical way in which orthographic representations are initially set up.     

Speed of phonological and orthographic processing as factors in dyslexia: electrophysiological evidence

The author investigated the hypothesis that speed of processing in the phonological and orthographic systems is one of the underlying variables of word-reading effectiveness. Speed of processing was assessed using measures of behavioral reaction time and electrophysiological latencies during phonological and orthographic task performance. Participants were 20 dyslexic and 20 normal-reading, male college students. An electrophysiological component complex (N1-P2-N2), as well as 2 other components (P3 and N4), was identified in both groups on each of the experimental tasks. Significant group differences were obtained only on the phonological tasks. Speed of processing during phonological judgment tasks was significantly prolonged among the dyslexic readers compared with the controls as reflected by P2, P3, and N4 latencies and reaction time. Between-task comparisons revealed significantly prolonged P2, P3, and N4 latencies on phonological compared with orthographic tasks in both dyslexic and normal readers, indicating that phonological classification of words may demand more time than orthographic classification. However, the gap score between speed of processing on the phonological and orthographic tasks was larger among the dyslexic readers and was observed mainly in P3 latency and reaction time. The highest correlation between word-reading accuracy score and the experimental measures was obtained in the dyslexic group with P3 latency gap score and in the control group with P2 latency gap score. The author proposes that slow phonological processing may cause "asynchrony" between the processing speeds within and between phonological and orthographic systems and may lead to a lack of efficient integration among the various subprocesses activated in reading, may slow down reading rate, and may impair word-reading effectiveness.     

On the time course of accessing meaning in a second language: An electrophysiological and behavioral investigation of translation recognition

In 2 experiments, relatively proficient Chinese-English bilinguals decided whether Chinese words were the correct translations of English words. Critical trials were those on which incorrect translations were related in lexical form or meaning to the correct translation. In Experiment 1, behavioral interference was revealed for both distractor types, but event-related potentials (ERPs) revealed a different time course for the 2 conditions. Semantic distractors elicited effects primarily on the N400 and late positive component (LPC), with a smaller N400 and a smaller LPC over the posterior scalp but a larger LPC over the anterior scalp relative to unrelated controls. In contrast, translation form distractors elicited a larger P200 and a larger LPC than did unrelated controls. To determine whether the translation form effects were enabled by the relatively long, 750-ms stimulus onset asynchrony (SOA) between words, a 2nd ERP experiment was conducted using a shorter, 300-ms, SOA. The behavioral results revealed interference for both types of distractors, but the ERPs again revealed different loci for the 2 effects. Taken together, the data suggest that proficient bilinguals activate 1st-language translations of words in the 2nd language after they have accessed the meaning of those words. The implications of this pattern for claims about the nature of cross-language activation when bilinguals read in 1 or both languages are discussed. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

Featural and configural face processing in adults and infants: a behavioral and electrophysiological investigation

We sought to elucidate the behavioral and electrophysiological correlates of face processing, in adults and infants, by manipulating either the featural or configural information within the face. Two different experiments are reported. In these experiments, event-related potentials (ERPs) were recorded from the scalp while adult, 8-month-old, and 4-month-old participants completed configural-change and featural-change face tasks. The infants also completed a behavioral visual paired-comparison task with featural and configural face changes. ERP results reveal hemispheric differences in processing featural but not configural changes for the N170 in adults. Furthermore, featural and configural changes are processed differently within the right and left hemispheres. The right hemisphere N170 is significantly greater for configural compared to featural changes. The left hemisphere N170, however, exhibits the opposite effect. Infant data suggest that similar to adults, 8-month-old, but not 4-month-old participants, exhibit similar hemispheric differences between featural and configural changes for the P400 component. Behavioral results suggest increased sensitivity to both featural and configural face changes in 8-month-olds compared to 4-month-olds.     

听觉呈现条件下汉语双字词语义和语音启动的ERP研究

在词汇决定实验中研究语义启动和语音启动,材料为通过听觉呈现的汉语双字词组成的词对(间隔600ms),记录行为数据和ERP数据,结果发现：(1)启动词与目标词之间的语义联系可显著改善对目标词的加工,表现为错误率降低、反应时缩短,以及N400波幅降低;(2)启动词与目标词之间的语音一致对目标词的加工既有干扰作用,又有促进作用。表现为错误率提高,但反应时趋向缩短,N400波幅亦呈下降趋势;(3)启动词与目标词首音相同比尾音相同有更大的干扰作用。     

字词认知N170成分及其发展

字词认知早期的N170成分是第一个对语言材料敏感的成分.最近对字词认知N170成分的研究主要集中在探讨其敏感性、偏侧化以及此成分的发展变化.大量研究认为字词N170成分的敏感性与正字法加工有关,但也有一些研究认为其受语音、语义调制.对于此成分的偏侧化研究结果较一致认为是左侧化.最近的发展研究对N170成分进行探讨,取得了一些成果.在剖析现有研究基础上,本文认为应对字词认知N170成分的偏侧化、功能分离等问题进行深入研究.     

Asymmetrical hemisphere activation enhances global–local processing

Decades of research focusing on the neurophysiological underpinnings related to global–local processing of hierarchical stimuli have associated global processing with the right hemisphere and local processing with the left hemisphere. The current experiment sought to expand this research by testing the causal contributions of hemisphere activation to global–local processing. To manipulate hemisphere activation, participants engaged in contralateral hand contractions. Then, EEG activity and attentional scope were measured. Right-hand contractions caused greater relative left-cortical activity than left-hand contractions. Participants were more narrowly focused after left-hemisphere activation than after right-hemisphere activation. Moreover, N1 amplitudes to local targets in the left hemisphere were larger after left-hemisphere activation than after right-hemisphere activation. Consistent with past research investigating hemispheric asymmetry and attentional scope, the current results suggest that manipulating left (right) hemisphere activity enhanced local (global) attentional processing.     

Asymmetrical hemisphere activation enhances global–local processing

Decades of research focusing on the neurophysiological underpinnings related to global–local processing of hierarchical stimuli have associated global processing with the right hemisphere and local processing with the left hemisphere. The current experiment sought to expand this research by testing the causal contributions of hemisphere activation to global–local processing. To manipulate hemisphere activation, participants engaged in contralateral hand contractions. Then, EEG activity and attentional scope were measured. Right-hand contractions caused greater relative left-cortical activity than left-hand contractions. Participants were more narrowly focused after left-hemisphere activation than after right-hemisphere activation. Moreover, N1 amplitudes to local targets in the left hemisphere were larger after left-hemisphere activation than after right-hemisphere activation. Consistent with past research investigating hemispheric asymmetry and attentional scope, the current results suggest that manipulating left (right) hemisphere activity enhanced local (global) attentional processing.