Processing Cantonese lexical tones: Evidence from oddball paradigms

Neuroelectrical and behavioral correlates of constructed action recognition in Finnish Sign language

Language can be processed with varying levels of attentional involvement; consequently, the interplay between the language and attentional systems in the brain has been extensively studied in spoken languages. However, in signed languages (SLs), this interplay is less well understood. Here, we use Constructed Action (CA) - a meaning-making strategy based on enactment - as a window into the attentional mechanisms recruited in signed language comprehension. We explored the attentional processing of CA by identifying the sequence of processes involved and in which stage CA and its types might be processed differently. Finally, we investigated the associations between the brain mechanisms of CA detection and their behavioral manifestations, as well as with components of attention of the Attention Network Test (ANT). We also measured the electrophysiological correlates of performance on an oddball CA detection task in deaf and hearing L1 signers. We found that processes involved in all signers' active detection of CA involved automatic (indexed by N1 and P2) and attention-based processes (indexed by N2s and P3s). N2 posterior bilateral were also more negative for tokens of overt CA than for PT-only signs, while P3a was more positive for all types of CA than for PT. No significant results were found regarding the ANT. We conclude that specific attentional involvement in CA detection is triggered by the increasing enacting elements and saliency involved in CA. This study yielded new insights into the functional interaction between the neural mechanisms underlying attentional control and those mediating CA processing in SL.

Mismatch Negativity Unveils Tone Perception Strategies and Degrees of Tone Merging: The Case of Macau Cantonese

BACKGROUND/OBJECTIVES

Previous studies have examined the role of working memory in cognitive tasks such as syntactic, semantic, and phonological processing, thereby contributing to our understanding of linguistic information management and retrieval. However, the real-time processing of phonological information-particularly in relation to suprasegmental features like tone, where its contour represents a time-varying signal-remains a relatively underexplored area within the framework of Information Processing Theory (IPT). This study aimed to address this gap by investigating the real-time processing of similar tonal information by native Cantonese speakers, thereby providing a deeper understanding of how IPT applies to auditory processing.

METHODS

Specifically, this study combined assessments of cognitive functions, an AX discrimination task, and electroencephalography (EEG) to investigate the discrimination results and real-time processing characteristics of native Macau Cantonese speakers perceiving three pairs of similar tones.

RESULTS

The behavioral results confirmed the completed merging of T2-T5 in Macau Cantonese, and the ongoing merging of T3-T6 and T4-T6, with perceptual merging rates of 45.46% and 27.28%, respectively. Mismatch negativity (MMN) results from the passive oddball experiment revealed distinct temporal processing patterns for the three tone pairs. Cognitive functions, particularly attention and working memory, significantly influenced tone discrimination, with more pronounced effects observed in the mean amplitude of MMN during T4-T6 discrimination. Differences in MMN peak latency between T3-T6 and T4-T6 further suggested the use of different perceptual strategies for these contour-related tones. Specifically, the T3-T6 pair can be perceived through early signal input, whereas the perception of T4-T6 relies on constant signal input.

CONCLUSIONS

This distinction in cognitive resource allocation may explain the different merging rates of the two tone pairs. This study, by focusing on the perceptual difficulty of tone pairs and employing EEG techniques, revealed the temporal processing of similar tones by native speakers, providing new insights into tone phoneme processing and speech variation.

The neural mechanisms underlying the processing of consonant, vowel and tone during Chinese typing: an fNIRS study

Many studies have explored the role of consonant, vowel, and tone in Chinese word identification or sentence comprehension. However, few studies have explored their roles and neural basis during Chinese word production, especially when involving neural basis. The present fNIRS study investigated the neural mechanisms of consonant, vowel, and tone processing during Chinese typing. Participants were asked to name the Chinese characters displayed on a computer screen by typing on a keyboard while hearing a simultaneously presented auditory stimulus. The auditory stimulus was either consistent with the characters' pronunciation (consistent condition) or mismatched in the consonant, vowel, or tone of the character pronunciation. The fNIRS results showed that compared with the consistent condition (as baseline), the consonant mismatch condition evoked lower levels of oxygenated hemoglobin (HbO) activation in the left inferior frontal gyrus Broca's triangle and left superior temporal gyrus. Vowel mismatch condition evoked a higher level of HbO activation in the top of the left inferior frontal gyrus and left middle frontal gyrus. The regions and patterns of brain activation evoked by tone mismatch were the same as those of vowel mismatch. The study indicated that consonant, vowel and tone all play a role in Chinese character production. The sensitive brain areas were all in the left hemisphere. However, the neural mechanism of consonant processing differed from vowel processing in both brain regions and patterns, while tone and vowel processing shared the same regions.

Phonetic and Lexical Encoding of Tone in Cantonese Heritage Speakers

Heritage speakers contend with at least two languages: the less dominant first language (L1), that is, the heritage language, and the more dominant second language (L2). In some cases, their L1 and L2 bear striking phonological differences. In the current study, we investigate Toronto-born Cantonese heritage speakers and their maintenance of Cantonese lexical tone, a linguistic feature that is absent from English, the more dominant L2. Across two experiments, Cantonese heritage speakers were tested on their phonetic/phonological and lexical encoding of tone in Cantonese. Experiment 1 was an AX discrimination task with varying inter-stimulus intervals (ISIs), which revealed that heritage speakers discriminated tone pairs with disparate pitch contours better than those with shared pitch contours. Experiment 2 was a medium-term repetition priming experiment, designed to extend the findings of Experiment 1 by examining tone representations at the lexical level. We observed a positive correlation between English dominance and priming in tone minimal pairs that shared contours. Thus, while increased English dominance does not affect heritage speakers' phonological-level representations, tasks that require lexical access suggest that heritage Cantonese speakers may not robustly and fully distinctively encode Cantonese tone in lexical memory.

The effects of alphabetic literacy, linguistic-processing demand and tone type on the dichotic listening of lexical tones

Brain lateralization of lexical tone processing remains a matter of debate. In this study we used a dichotic listening paradigm to examine the influences of the knowledge of Jyutping (a romanization writing system which provides explicit Cantonese tone markers), linguistic-processing demand and tone type on the ear preference pattern of native tone processing in Hong Kong Cantonese speakers. While participants with little knowledge of Jyutping showed a previously reported left-ear advantage (LEA), those with a good level of Jyutping expertise exhibited either a right-ear advantage or bilateral processing during lexical tone identification and contour tone discrimination, respectively. As for the effect of linguistic-processing demand, while an LEA was found in acoustic/phonetic perception situations, this advantage disappeared and was replaced by a bilateral pattern in conditions that involved a greater extent of linguistic processing, suggesting an increased involvement of the left hemisphere. Regarding the effect of tone type, both groups showed an LEA in level tone discrimination, but only the Jyutping group demonstrated a bilateral pattern in contour tone discrimination. Overall, knowledge of written codes of tones, greater degree of linguistic processing and contour tone processing seem to influence the brain lateralization of lexical tone processing in native listeners of Cantonese by increasing the recruitment of the left-hemisphere language network.

A step forward in the quest for a mobile EEG-designed epoch for psychophysiological studies

The aim of this study was to compare a reconfigurable mobile electroencephalography (EEG) system (M-EMOTIV) based on the Emotiv Epoc® (which has the ability to record up to 14 electrode sites in the 10/20 International System) and a commercial, clinical-grade EEG system (Neuronic MEDICID-05®), and then validate the rationale and accuracy of recordings obtained with the prototype proposed. In this approach, an Emotiv Epoc® was modified to enable it to record in the parieto-central area. All subjects (15 healthy individuals) performed a visual oddball task while connected to both devices to obtain electrophysiological data and behavioral responses for comparative analysis. A Pearson's correlation analysis revealed a good between-devices correlation with respect to electrophysiological measures. The present study not only corroborates previous reports on the ability of the Emotiv Epoc® to suitably record EEG data but presents an alternative device that allows the study of a wide range of psychophysiological experiments with simultaneous behavioral and mobile EEG recordings.

Effects of native language experience on Mandarin lexical tone processing in proficient second language learners

Learning the acoustic and phonological information in lexical tones is significant for learners of tonal languages. Although there is a wealth of knowledge from studies of second language (L2) tone learning, it remains unclear how L2 learners process acoustic versus phonological information differently depending on whether their first language (L1) is a tonal language. In the present study, we first examined proficient L2 learners of Mandarin with tonal and nontonal L1 in a behavioral experiment (identifying a Mandarin tonal continuum) to construct tonal contrasts that could differentiate the phonological from the acoustic information in Mandarin lexical tones for the L2 learners. We then conducted an ERP experiment to investigate these learners' automatic processing of acoustic and phonological information in Mandarin lexical tones by mismatch negativity (MMN). Although both groups of L2 learners showed similar behavioral identification features for the Mandarin tonal continuum as native speakers, L2 learners with nontonal L1, as compared with both native speakers and L2 learners with tonal L1, showed longer reaction time to the tokens of the Mandarin tonal continuum. More importantly, the MMN data further revealed distinct roles of acoustic and phonological information on the automatic processing of L2 lexical tones between the two groups of L2 learners. Taken together, the results indicate that the processing of acoustic and phonological information in L2 lexical tones may be modulated by L1 experience with a tonal language. The theoretical implications of the current study are discussed in light of models of L2 speech learning.

Effects of Gender and Apolipoprotein E on Novelty MMN and P3a in Healthy Elderly and Amnestic Mild Cognitive Impairment

Background: The apolipoprotein E epsilon4 (ApoE ε4) allele and female gender may be important risk factors for the development of Alzheimer’s disease and amnestic mild cognitive impairment (aMCI). Novelty mismatch negativity (MMN) represents the pre-attentive index of deviance detection and P3a represents the attention orienting response. Furthermore, MMN and P3a components have been reported to be potential markers in aMCI. Therefore, this study will investigate the effects of gender and ApoE on auditory novelty MMN and P3a and their relationship to neuropsychological performance in aMCI.

Methods: Thirty nine aMCI subjects and 44 controls underwent neuropsychological assessment and ApoE genotyping. Novelty MMN and P3a components were investigated during an auditory novelty oddball task.

Results: Firstly, novelty MMN latency was significantly shorter in aMCI than in healthy control (HC) group. Secondly, novelty MMN latency was negatively correlated with episodic memory in aMCI, but not in HC. Novelty P3a latency was negatively correlated with information processing speed in all subjects. For gender effect, novelty MMN latency was shorter in aMCI females than in HC females. Moreover, novelty P3a amplitudes were lower in males than in females in both aMCI and HC. For the effect of ApoE status, novelty MMN latency was shorter in aMCI ApoE ε4- than HC ApoE ε4-.

Conclusion: aMCI presents altered pre-attentive processing indexed by novelty MMN components. Furthermore, there may be a compensatory mechanism on the impaired processing in aMCI. It further suggests that aMCI female and ApoE ε4- recruited the compensatory mechanism.

Differential sensitivity to changes in pitch acceleration in the auditory brainstem and cortex

The cortical pitch-specific response (CPR) is differentially sensitive to pitch contours varying in rate of acceleration-time-variant Mandarin Tone2 (T2) versus constant, linear rising ramp (Linear)-as a function of language experience (Krishnan, Gandour, & Suresh, 2014). CPR and brainstem frequency following response (FFR) data were recorded concurrently from native Mandarin listeners using the same stimuli. Results showed that T2 elicited larger responses than Linear at both cortical and brainstem levels (CPR: Na-Pb, Pb-Nb; FFR). However, Pb-Nb exhibited a larger difference in magnitude between T2 and Linear than either Na-Pb or FFR. This finding highlights differential weighting of brain responses elicited by a specific temporal attribute of pitch. Consistent with the notion of a distributed, integrated hierarchical pitch processing network, temporal attributes of pitch are differentially weighted by subcortical and cortical level processing.

Language-dependent changes in pitch-relevant neural activity in the auditory cortex reflect differential weighting of temporal attributes of pitch contours

There remains a gap in our knowledge base about neural representation of pitch attributes that occur between onset and offset of dynamic, curvilinear pitch contours. The aim is to evaluate how language experience shapes processing of pitch contours as reflected in the amplitude of cortical pitch-specific response components. Responses were elicited from three nonspeech, bidirectional (falling-rising) pitch contours representative of Mandarin Tone 2 varying in location of the turning point with fixed onset and offset. At the frontocentral Fz electrode site, Na-Pb and Pb-Nb amplitude of the Chinese group was larger than the English group for pitch contours exhibiting later location of the turning point relative to the one with the earliest location. Chinese listeners' amplitude was also greater than that of English in response to those same pitch contours with later turning points. At lateral temporal sites (T7/T8), Na-Pb amplitude was larger in Chinese listeners relative to English over the right temporal site. In addition, Pb-Nb amplitude of the Chinese group showed a rightward asymmetry. The pitch contour with its turning point located about halfway of total duration evoked a rightward asymmetry regardless of group. These findings suggest that neural mechanisms processing pitch in the right auditory cortex reflect experience-dependent modulation of sensitivity to weighted integration of changes in acceleration rates of rising and falling sections and the location of the turning point.