Event-related Brain Potentials Research Articles

Slips of the tongue in patients with Gilles de la Tourette syndrome

BackgroundMotor and vocal tics are the main symptom of Gilles de la Tourette-syndrome (GTS). A particular complex vocal tic comprises the utterance of swear words, termed coprolalia. Since taboo words are socially inappropriate, they are normally suppressed by people, which implies cognitive control processes.MethodTo investigate the control of the unintentional pronunciation of taboo words and the associated processes of conflict monitoring, we used the “Spoonerisms of Laboratory Induced Predisposition” (SLIP) paradigm. Participants read multiple inductor word pairs with the same phonemes, followed by pronouncing a target pair with inverse phonemes. This led to a conflict between two competing speech plans: the correct word pair and the word pair with inverted phonemes. Latter speech error, a spoonerism, could result in a neutral or taboo word. We investigated 19 patients with GTS and 23 typically developed controls (TDC) and measured participants’ electroencephalography (EEG) during the SLIP task.ResultsAt the behavioral level less taboo than neutral word spoonerisms occurred in both groups without significant differences. Event-related brain potentials (ERP) revealed a difference between taboo and neutral word conditions in the GTS group at the midline electrodes in a time range of 250–400 ms after the speech prompt, which was not found in the TDC group. The extent of this effect depended on the number of inductor word pairs, suggesting an increasing level of cognitive control in the GTS group.ConclusionThe differences between taboo and neutral word conditions in patients with GTS compared to TDC suggest an altered recruitment of cognitive control processes in GTS, likely enlisted to suppress taboo words.

Beyond Explicit Acknowledgment: Brain Response Evidence of Human Skepticism towards Robotic Emotions

Using the N400 component of event-related brain potentials, a neurophysiological marker associated with processing incongruity, we examined brain responses to sentences spoken by a robot that had no arms or legs. Statements concerning physically impossible actions (e.g., knitting) elicit significant N400 responses, reflecting that participants perceived these statements as incongruent with the robot’s physical condition. However, this effect was attenuated for participants who indicated that the robot could have hidden limbs, indicating that expectations modify the way an agent’s utterances are interpreted. When it came to statements relating to emotional capabilities a distinct pattern was found. Although participants acknowledged that the robot could have emotions, there were significant N400 responses to statements about the robot’s emotional experiences (e.g., feeling happy). This effect was not modified by participants’ beliefs, suggesting a cognitive challenge of accepting robots as capable of experiencing emotions. Our findings thus point to a boundary in human acceptance of artificial social agents: while physical attributes may be negotiable based on expectations, emotional expressions are more difficult to establish as credible. By elucidating the cognitive mechanisms at play, our study informs the design of social robots that are capable of more effective communication to better support social connectivity and human well-being.

Relevance acquisition through motivational incentives: Modeling the time-course of associative learning and the role of visual features

Abstract Motivational relevance associated with symbolic stimuli impacts both neural and behavioral responses, similar to visual stimuli with inherent emotional valence. However, the specific effects of associated relevance on early sensory stages and lexico-semantic processing of these stimuli remain unclear, particularly considering the role of low-level visual features in relevance acquisition. To address these issues, we employed an associative learning paradigm in which we manipulated visual features, but not the stimuli themselves. The study (N = 48) included a learning phase, where pseudowords were associated with either gain, loss, or neutral outcomes. This was followed by a test phase the next day, involving an old/new decision task, in which stimuli were presented in either in the same or a different font. During both phases, pupil responses and event-related brain potentials (P1, EPN, LPC, P3) were measured. Stronger pupil responses and increased neural activation in early visual encoding (P1) and lexico-semantic processing (EPN) were observed during relevance acquisition, particularly for loss associations. After relevance acquisition, the most substantial effect on modulating lexico-semantic processing was observed for gain associations, as evidenced by both behavioral responses and neural activity. During the test phase, exposure to incongruent visual features of the stimuli influenced the same processes that were observed during relevance acquisition. Notably, these effects of visual feature congruence were independent of those of associated motivational relevance. These results highlight the dynamic nature of motivational relevance effects, revealing differential effects observed during acquisition and the test phase, as well as between earlier perceptual processing and later neural and behavioral responses.

An event-related potential investigation of the influence of bilingualism on disambiguating homonyms in older adults.

Ambiguity is ubiquitous in language; lexical ambiguity refers to instances where a single word has multiple meanings. The current investigation examined homonyms, words that have the same orthography and pronunciation in English but multiple meanings (e.g., BANK, meaning "financial institution" or "river's edge"). The processing of homonyms requires the engagement of executive control processes, for example, to select the appropriate meaning of the homonym while reducing interference from other meanings. Executive function processes are known to change over the lifespan and may be impacted by experiential factors such as bilingualism. The present study uses event-related brain potentials as an index of lexical access to examine whether bilingualism influences homonym processing in older adults. The results indicate that patterns of lexical access differ as a function of bilingual status in older adults and compared to young adults, suggesting that language experience may moderate language processing in both young and older adults, at least in situations where language processing is demanding on executive function, such as in the processing of homonyms. Importantly, we show that older bilinguals show a somewhat similar pattern of ambiguity processing as their younger counterparts, while age differences were observed in monolinguals when comparing across studies. This suggests that bilingual language experience may have a mitigating impact on age-related changes in ambiguity processing. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

From psychophysiology to brain imaging: forty-five years MMN history of investigating acoustic change sensitivity.

Forty-five years have passed since the first publication of the mismatch negativity (MMN) event-related brain potential (ERP) component. The first 10years of research hardly gained any particular attention of the scientific community interested in acoustic perception. Debates on the nature of sensation versus perception were going on, and the technical possibilities to record ERPs, called in general evoked potentials, were very limited. Subtle changes in pure tone frequency or intensity giving rise to the MMN component were first investigated in humans. The background of the theoretical model developed by Risto Näätänen was the orientation reaction model of E.N. Sokolov published in 1963 so that the MMN was seen first as an electrophysiological correlate of auditory change detection. This fundamental ability of the auditory system seen as crucial for survival led to the development of the first animal model of the MMN (Csépe et al. in Clin Neurophysiol 66: 571-578, 1987). Indeed, it was confirmed that the MMN was the brain correlate of subtle changes detected that might alert to potential threats in the environment and direct the behavioral orientation. The investigations performed after 2000 introduced complex models and more sophisticated methods, both in animal and human studies, so that the MMN method was on the way to become a tool on the first place and not the main goal of research. This approach was further strengthened by the increasing number of studies on different clinical populations aiming at future applications. The aim of our review is to describe and redefine what the MMN may reflect in auditory perception and to show why and how this brain correlate of changes in the auditory scene can be used as a valuable tool in cognitive neuroscience research. We refer to publications selectedto underly theargument the MMN cannot be classified anymore as a sign of simple change detection and not all the indicators used to confirm howgenuine theMMN elicited byvariations of tones are valid for those tospeechcontrasts. We provide a fresh view on the broadly used MMN models, provided by some influential publications as well as on the unwritten history of MMN research aiming to give revised picture on what the MMN may truly reflect. We show how the focus and terminology of the MMN research have changed and what kind of misunderstandings and seemingly contradictive results prevent the MMN community to accept a generally usable cognitive model.

Unpleasant emotion inhibits attentional focus toward a peripheral target in a visual search: an ERP study.

Previous studies have found that emotional states affect the extent of attention, and the effect has been explained by adaptive views. If the adaptive explanations are true, emotion should modulate attentional focus toward a peripheral stimulus. The present study investigated if emotion affects the focus of attention toward a peripheral target in a visual search paradigm with event-related brain potential (ERP) measurement. In each trial of the experiment, participants performed a visual search task after an emotion (unpleasant, neutral, or pleasant) was induced by presenting an international affective picture system (IAPS) image. We measured N2pc, which is an ERP index reflecting attentional focus toward a peripheral target in a visual search, and compared the amplitudes among the emotion conditions. According to the adaptive view of emotional effects on cognition, this study hypothesized that unpleasant emotion would enhance the focus of attention, and pleasant emotion would inhibit it. These hypotheses predicted that N2pc amplitude would increase with unpleasant emotion and decrease with pleasant emotion. However, this study obtained inconsistent results; N2pc amplitude decreased in the unpleasant condition, and there was no significant effect of pleasant emotion on the ERP. The results suggest that unpleasant emotion inhibited the attentional focusing process. This is the first report to examine how emotion modulates the focus of attention toward a peripheral target in a visual search by using ERP. The findings contribute to understanding the relationship between emotion and cognition.

FC-TFS-CGRU: A Temporal-Frequency-Spatial Electroencephalography Emotion Recognition Model Based on Functional Connectivity and a Convolutional Gated Recurrent Unit Hybrid Architecture.

The gated recurrent unit (GRU) network can effectively capture temporal information for 1D signals, such as electroencephalography and event-related brain potential, and it has been widely used in the field of EEG emotion recognition. However, multi-domain features, including the spatial, frequency, and temporal features of EEG signals, contribute to emotion recognition, while GRUs show some limitations in capturing frequency-spatial features. Thus, we proposed a hybrid architecture of convolutional neural networks and GRUs (CGRU) to effectively capture the complementary temporal features and spatial-frequency features hidden in signal channels. In addition, to investigate the interactions among different brain regions during emotional information processing, we considered the functional connectivity relationship of the brain by introducing a phase-locking value to calculate the phase difference between the EEG channels to gain spatial information based on functional connectivity. Then, in the classification module, we incorporated attention constraints to address the issue of the uneven recognition contribution of EEG signal features. Finally, we conducted experiments on the DEAP and DREAMER databases. The results demonstrated that our model outperforms the other models with remarkable recognition accuracy of 99.51%, 99.60%, and 99.59% (58.67%, 65.74%, and 67.05%) on DEAP and 98.63%, 98.7%, and 98.71% (75.65%, 75.89%, and 71.71%) on DREAMER in a subject-dependent experiment (subject-independent experiment) for arousal, valence, and dominance.

Effects of anxiety state on N400 event-related brain potential response to unexpected semantic stimuli

Emotional states can influence how people use meaningful context to make predictions about what comes next. To measure whether state anxiety influences such prediction, we used the N400 event-related brain potential (ERP) response to semantic stimuli, whose amplitude is smaller (less negative) when the stimulus is more predicted based on preceding context. Participants (n = 28) were randomized to one of two groups, who underwent either an “anxious-uncertainty” procedure previously shown to increase anxiety, or a control procedure. Both before and after this procedure, participants’ ERPs were recorded while they viewed category definitions (e.g., “a type of fruit”), each followed by a target word that was either a high-typicality category exemplar (“apple”), low-typicality exemplar (“cherry”), or non-exemplar (“clamp”) of the category. Participants’ task was to respond by pressing one of two buttons to indicate whether the target represented a member of the category. As expected, based on previous work, overall, N400 amplitudes were largest (most negative) in response to non-exemplars, intermediate to low-typicality exemplars, and smallest to high-typicality exemplars. N400 amplitudes were larger to non-exemplars after the anxious-uncertainty procedure than after the control procedure. N400 amplitudes to both types of exemplars did not differ after the anxious-uncertainty procedure versus the control procedure. The results are consistent with participants devoting more neural resources to processing contextually unexpected items under anxious states, rather than anxiety facilitating processing of expected items.

Machine Learning Classification of Event-Related Brain Potentials during a Visual Go/NoGo Task.

Machine learning (ML) methods are increasingly being applied to analyze biological signals. For example, ML methods have been successfully applied to the human electroencephalogram (EEG) to classify neural signals as pathological or non-pathological and to predict working memory performance in healthy and psychiatric patients. ML approaches can quickly process large volumes of data to reveal patterns that may be missed by humans. This study investigated the accuracy of ML methods at classifying the brain's electrical activity to cognitive events, i.e., event-related brain potentials (ERPs). ERPs are extracted from the ongoing EEG and represent electrical potentials in response to specific events. ERPs were evoked during a visual Go/NoGo task. The Go/NoGo task requires a button press on Go trials and response withholding on NoGo trials. NoGo trials elicit neural activity associated with inhibitory control processes. We compared the accuracy of six ML algorithms at classifying the ERPs associated with each trial type. The raw electrical signals were fed to all ML algorithms to build predictive models. The same raw data were then truncated in length and fitted to multiple dynamic state space models of order nx using a continuous-time subspace-based system identification algorithm. The 4nx numerator and denominator parameters of the transfer function of the state space model were then used as substitutes for the data. Dimensionality reduction simplifies classification, reduces noise, and may ultimately improve the predictive power of ML models. Our findings revealed that all ML methods correctly classified the electrical signal associated with each trial type with a high degree of accuracy, and accuracy remained high after parameterization was applied. We discuss the models and the usefulness of the parameterization.

Quantifying the effects of practicing a semantic task according to subclinical schizotypy

The learning ability of individuals within the schizophrenia spectrum is crucial for their psychosocial rehabilitation. When selecting a treatment, it is thus essential to consider the impact of medications on practice effects, an important type of learning ability. To achieve this end goal, a pre-treatment test has to be developed and tested in healthy participants first. This is the aim of the current work, which takes advantage of the schizotypal traits present in these participants to preliminary assess the test’s validity for use among patients. In this study, 47 healthy participants completed the Schizotypal Personality Questionnaire (SPQ) and performed a semantic categorization task twice, with a 1.5-hour gap between sessions. Practice was found to reduce reaction times (RTs) in both low- and high-SPQ scorers. Additionally, practice decreased the amplitudes of the N400 event-related brain potentials elicited by semantically matching words in low SPQ scorers only, which shows the sensitivity of the task to schizotypy. Across the two sessions, both RTs and N400 amplitudes had good test–retest reliability. This task could thus be a valuable tool. Ongoing studies are currently evaluating the impact of fully deceptive placebos and of real antipsychotic medications on these practice effects. This round of research should subsequently assist psychiatrists in making informed decisions about selecting the most suitable medication for the psychosocial rehabilitation of a patient.

Response monitoring in math-anxious individuals in an arithmetic task

We examine whether math anxiety is related to altered response monitoring in an arithmetic task. Response-locked event-related brain potentials (ERPs) were evaluated in 23 highly (HMA) and 23 low math-anxious (LMA) individuals while they performed an arithmetic verification task. We focused on two widely studied ERPs elicited during error processing: error-related negativity (ERN) and error positivity (Pe). Correct-related negativity (CRN), an ERP elicited after a correct response, was also studied. The expected ERN following errors was found, but groups did not differ in its amplitude. Importantly, LMA individuals showed less negative CRN and more positive Pe amplitudes than their more anxious peers, suggesting more certainty regarding response accuracy and better adaptive behavioral adjustment after committing errors in an arithmetic task in the LMA group. The worse control over response performance and less awareness of correct responses in the HMA group might reduce their ability to ‘learn from errors’.

Emotional congruency between faces and words benefits emotional judgments in women: An event-related potential study

The present study aimed to investigate the effects of emotional congruency between faces and words on word evaluation through event-related brain potentials (ERPs). To this end, 20 women performed a face-word congruency task in which an emotional face was presented simultaneously with an affective word in a non-superimposed format. Participants had to evaluate the emotional valence of the word in three different conditions: congruent, incongruent, and control. The emotionally congruent words were categorized faster and more accurately than the incongruent ones. In addition, the emotionally congruent words elicited higher P3/LPP amplitudes than the incongruent ones. These results indicate a beneficial effect of emotional face-word congruency on emotional judgments of words.

Evaluation of Brain Electrical Activity of Visual Working Memory with Time-Frequency Analysis.

The term visual working memory (VWM) refers to the temporary storage of visual information. In electrophysiological recordings during the change detection task which relates to VWM, contralateral negative slow activity was detected. It was found to occur during the information is kept in memory and it was called contralateral delay activity. In this study, the characteristics of electroencephalogram frequencies of the contralateral and ipsilateral responses in the retention phase of VWM were evaluated by using time-frequency analysis (discrete wavelet transform [DWT]) in the change detection task. Twenty-six volunteers participated in the study. Event-related brain potentials (ERPs) were examined, and then a time-frequency analysis was performed. A statistically significant difference between contralateral and ipsilateral responses was found in the ERP. DWT showed a statistically significant difference between contralateral and ipsilateral responses in the delta and theta frequency bands range. When volunteers were grouped as either high or low VWM capacity the time-frequency analysis between these groups revealed that high memory capacity groups have a significantly higher negative coefficient in alpha and beta frequency bands. This study showed that during the retention phase delta and theta bands may relate to visual memory retention and alpha and beta bands may reflect individual memory capacity.

Preexposure to one social threat alters responses to another social threat: Behavioral and electrophysiological evidence.

A recent Cyberball study has indicated that the experience of loss of control can affect how people process subsequent social exclusion. This "preexposure effect" supports the idea of a common cognitive system involved in the processing of different types of social threats. To test the validity of this assumption in the current study, we reversed the sequence of the preexposure setup. We measured the effects of social exclusion on the subsequent processing of loss of control utilizing event-related brain potentials (ERPs) and self-reports. In the control group (CG, n = 26), the transition to loss of control elicited significant increases in both the P3 amplitude and the self-reported negative mood. Replicating the results of the previous preexposure study, these effects were significantly reduced by the preexposure to an independent social threat (here: social exclusion). In contrast to previous findings, these effects were not modulated by the discontinuation (EG1disc, n = 25) or continuation (EG2cont, n = 24) of the preexposure threat. Given that the P3 effect is related to the violation of subjective expectations, these results support the notion that preexposure to a specific social threat has widespread effects on the individuals' expectancy of upcoming social participation and control.

Event-Related Brain Potentials N140 and P300 during Somatosensory Go/NoGo Tasks Are Modulated by Movement Preparation.

The Go/NoGo task requires attention and sensory processing to distinguish a motor action cue or 'Go stimulus' from a 'NoGo stimulus' requiring no action, as well as motor preparation for a rapid Go stimulus response. The neural activity mediating these response phases can be examined non-invasively by measuring specific event-related brain potentials (ERPs) using electroencephalography. However, it is critical to determine how different task conditions, such as the relationship between attention site and movement site, influence ERPs and task performance. In this study, we compared attention-associated ERP components N140 and P300, the performance metrics reaction time (RT) and accuracy (%Error) and movement-related cortical potentials (MRCPs) between Go/NoGo task trials in which attention target and movement site were the same (right index finger movement in response to right index finger stimulation) or different (right index finger movement in response to fifth finger stimulation). In other Count trials, participants kept a running count of target stimuli presented but did not initiate a motor response. The N140 amplitudes at electrode site Cz were significantly larger in Movement trials than in Count trials regardless of the stimulation site-movement site condition. In contrast, the P300 amplitude at Cz was significantly smaller in Movement trials than in Count trials. The temporal windows of N140 and P300 overlapped with the MRCP. This superposition may influence N140 and P300 through summation, possibly independent of changes in attentional allocation.

The Processing of Phi-features in Sentences with Third-person Pronoun: An ERP Study in Turkish

The relationship between Person and Number features is often addressed in both theoretical and experimental studies. It is noteworthy that the discussion on how these features are processed has evolved over time towards how Person and Number features are structured in constructions with different persons (first person, second person, third person). While some studies state that Person and Number features can only be tested with third-person sentences (Manchini et al., 2011; Mancini et al., 2014), other studies state that these features can be tested with all person pronouns except R-expressions (regular noun phrases) (Ackema & Neeleman, 2019). In the literature, it is noteworthy that the relationship between the processing of Person and Number features has been tested with first- and second-person pronouns and R-expressions, but there is no study testing the issue with third-person pronouns. The aim of this study was to investigate whether there is a difference in the processing of Person and Number features in sentences with third-person pronouns in Turkish using Event-related Brain Potentials (ERPs). In this study, three conditions, namely Grammatical, Person Mismatch and Number Mismatch, were presented visually in words to 33 participants. In the study, a widespread N400 component was observed in both the processing of the Person feature and the processing of the Number feature. It was found that there was no difference between the two features in the corresponding time window. However, in the next time window, a late N400 component was observed in the processing of the Number feature, while a positivity (P600) was observed in the processing of the Person feature. In this time window, there is a difference in the processing of the Person and Number features. In conclusion, this study found that there is a difference in the processing of the Person and Number features in sentences with third-person pronouns in Turkish. It is suggested that the P600 finding in the processing of the Person feature reflects the difficulty in processing this feature. It is suggested that the late N400 finding in the processing of the Number feature may be due to the load it imposes on the processing process due to the fact that the morphological appearance of the Number feature in verb conjugation is parallel to nominal pluralisation, and the greater demand on working memory as the resolution of the Number mismatch involves more alternatives than the Person mismatch.

Registered replication report of the construct validity of the error-related negativity (ERN): A multi-site study of task-specific ERN correlations with internalizing and externalizing symptoms.

Intact cognitive control is critical for goal-directed behavior and is widely studied using the error-related negativity (ERN). A common assumption in such studies is that ERNs recorded during different experimental paradigms reflect the same construct or functionally equivalent processes and that ERN is functionally distinct from other error-monitoring event-related brain potentials (ERPs; error positivity [Pe]), other neurophysiological indices of cognitive control (N2), and even other theoretically unrelated indices (visual N1). The present registered report represents a replication-plus-extension study of the psychometric validity of cognitive control ERPs and evaluated the convergent and divergent validity of ERN, Pe, N2, and visual N1 recorded during flanker, Stroop, and Go/no-go tasks. Data from 182 participants were collected from two study sites, and ERP psychometric reliability and validity were evaluated. Findings supported replication of convergent and divergent validity of ERN, Pe, and ΔPe (error minus correct)-these ERPs correlated more with themselves across tasks than with other ERPs measured during the same task. Convergent validity of ΔERN across tasks was not replicated, despite high internal consistency. ERN strongly correlated with N2 at levels similar or higher than those in support of convergent validity for other ERPs, and the present study failed to provide evidence of divergent validity for ERN and Pe from N2 or N1. ERN and ΔERN were unrelated to internalizing or externalizing symptoms. Findings underscore the importance of considering the psychometric validity of ERPs, as it provides a foundation for interpreting and comparing ERPs across tasks and studies.

Effects of the cardiac cycle on auditory processing: A preregistered study on mismatch negativity.

The systolic and diastolic phases of the cardiac cycle are known to affect perception and cognition differently. Higher order processing tends to be facilitated at systole, whereas sensory processing of external stimuli tends to be impaired at systole compared to diastole. The current study aims to examine whether the cardiac cycle affects auditory deviance detection, as reflected in the mismatch negativity (MMN) of the event-related brain potential (ERP). We recorded the intensity deviance response to deviant tones (70 dB) presented among standard tones (60 or 80 dB, depending on blocks) and calculated the MMN by subtracting standard ERP waveforms from deviant ERP waveforms. We also assessed intensity-dependent N1 and P2 amplitude changes by subtracting ERPs elicited by soft standard tones (60 dB) from ERPs elicited by loud standard tones (80 dB). These subtraction methods were used to eliminate phase-locked cardiac-related electric artifacts that overlap auditory ERPs. The endogenous MMN was expected to be larger at systole, reflecting the facilitation of memory-based auditory deviance detection, whereas the exogenous N1 and P2 would be smaller at systole, reflecting impaired exteroceptive sensory processing. However, after the elimination of cardiac-related artifacts, there were no significant differences between systole and diastole in any ERP components. The intensity-dependent N1 and P2 amplitude changes were not obvious in either cardiac phase, probably because of the short interstimulus intervals. The lack of a cardiac phase effect on MMN amplitude suggests that preattentive auditory processing may not be affected by bodily signals from the heart.

Number agreement processing in adolescents with and without developmental language disorder (DLD): evidence from event-related brain potentials

In morphologically richer languages, including French, one must learn the specific properties of number agreement in order to understand the language, and this learning process continues into adolescence. This study examined similarities and differences between French-speaking adolescents with and without developmental language disorder (DLD) when processing number agreement, and investigated how morpho-syntactic regularity affected language processing. Using event-related potentials (ERP) and only grammatical sentences with audio-visual mismatches, we studied ERP correlates to three types of number agreement: (1) regular determiner agreement in noun phrases, (2) regular subject-verb plural liaison, and (3) irregular subject-verb agreement. We also included a lexico-semantic mismatch condition to investigate lexico-semantic processing in our participants. 17 adolescents with DLD (M = 14.1 years) and 20 (pre)teens with typical language (TL, M = 12.2 years) participated in the study. Our results suggest three patterns. First, French-speaking teenagers without DLD are still consolidating their neurocognitive processing of morpho-syntactic number agreement and generally display ERP profiles typical of lower language proficiency than adult native speakers. Second, differences in morphosyntactic processing between teenagers with and without DLD seem to be limited to rule-based (regular) number agreement. Third, there is little evidence for corresponding differences in lexico-semantic processing.

Tonal and syllabic encoding in overt Cantonese Chinese speech production: An ERP study.

This study was conducted to investigate how syllables and lexical tones are processed in Cantonese speech production using the picture-word interference task with concurrent recording of event-related brain potentials (ERPs). Cantonese-speaking participants were asked to name aloud individually presented pictures and ignore an accompanying auditory word distractor. The target and distractor either shared the same word-initial syllable with the same tone (Tonal-Syllable related), the same word-initial syllable without the same tone (Atonal-Syllable related), the same tone only (Tone alone related), or were phonologically unrelated. Participants' naming responses were faster, relative to an unrelated control, when the target and distractor shared the same tonal- or atonal-syllable but null effect was found in the Tone alone related condition. The mean ERP amplitudes (per each 100-ms time window) were subjected to stimulus-locked (i.e., time-locked to stimulus onset) and response-locked (i.e., time-locked to response onset) analyses. Significant differences between related and unrelated ERP waves were similarly observed in both Tonal-Syllable related and Atonal-Syllable related conditions in the time window of 400-500 ms post-stimulus. However, distinct ERP effects were observed in these two phonological conditions within the 500-ms pre-response period. In addition, null effects were found in the Tone alone related condition in both stimulus-locked and response-locked analyses. These results suggest that in Cantonese spoken word production, the atonal syllable of the target is retrieved first and then associated with the target lexical tone, consistent with the view that tone has an important role to play at a late stage of phonological encoding in tonal language production.