Xuhai Chen

Amusia Results in Abnormal Brain Activity following Inappropriate Intonation during Speech Comprehension

Pitch processing is a critical ability on which humans’ tonal musical experience depends, and which is also of paramount importance for decoding prosody in speech. Congenital amusia refers to deficits in the ability to properly process musical pitch, and recent evidence has suggested that this musical pitch disorder may impact upon the processing of speech sounds. Here we present the first electrophysiological evidence demonstrating that individuals with amusia who speak Mandarin Chinese are impaired in classifying prosody as appropriate or inappropriate during a speech comprehension task. When presented with inappropriate prosody stimuli, control participants elicited a larger P600 and smaller N100 relative to the appropriate condition. In contrast, amusics did not show significant differences between the appropriate and inappropriate conditions in either the N100 or the P600 component. This provides further evidence that the pitch perception deficits associated with amusia may also affect intonation processing during speech comprehension in those who speak a tonal language such as Mandarin, and suggests music and language share some cognitive and neural resources.

Event-related potential correlates of the expectancy violation effect during emotional prosody processing.

The present study investigated the expectancy violation effects evoked by deviation in sentential emotional prosody (EP), and their association with the deviation patterns. Event-related potentials (ERPs) were recorded for mismatching EPs with different patterns of deviation and for matching control EPs while subjects performed emotional congruousness judgment in Experiment 1 and visual probe detection tasks in Experiment 2. In the control experiment, EPs and acoustically matched non-emotional materials were presented and ERPs were recorded while participants judged the sound intensity congruousness. It was found that an early negativity, whose peak latency varied with deviation pattern, was elicited by mismatching EPs relative to matching ones, irrespective of task-relevance. A late positivity was specifically induced by mismatching EPs, and was modulated by both deviation pattern and task-relevance. Moreover, these effects cannot be simply attributed to the change in non-emotional acoustic properties. These findings suggest that the brain detects the EP deviation rapidly, and then integrates it with context for comprehension, during which the emotionality plays a role of speeding up the perception and enhancing vigilance.

Enhanced brain susceptibility to negative stimuli in adolescents: ERP evidences

Background: Previous studies investigated neural substrates of emotional face processing in adolescents and its comparison with adults. As emotional faces elicit more of emotional expression recognition rather than direct emotional responding, it remains undetermined how adolescents are different from adults in brain susceptibility to emotionally stressful stimuli. Methods: Event-Related Potentials (ERPs) were recorded for highly negative (HN), moderately negative (MN), and neutral pictures in 20 adolescents and 20 adults while subjects performed a standard/deviant distinction task by pressing different keys, irrespective of the emotionality of deviant stimuli. Results: Adolescents exhibited more negative amplitudes for HN vs. neutral pictures in N1 (100–150 ms), P2 (130–190 ms), N2 (210–290 ms), and P3 (360–440 ms) components. In addition, adolescents showed more negative amplitudes for MN compared to neutral pictures in N1, P2, and N2 components. By contrast, adults exhibited significant emotion effects for HN stimuli in N2 and P3 amplitudes but not in N1 and P2 amplitudes, and they did not exhibit a significant emotion effect for MN stimuli at all these components. In the 210–290 ms time interval, the emotion effect for HN stimuli was significant across frontal and central regions in adolescents, while this emotion effect was noticeable only in the central region for adults. Conclusions: Adolescents are more emotionally sensitive to negative stimuli compared to adults, regardless of the emotional intensity of the stimuli, possibly due to the immature prefrontal control system over the limbic emotional inputs during adolescence.

The Contribution of Sound Intensity in Vocal Emotion Perception: Behavioral and Electrophysiological Evidence

Although its role is frequently stressed in acoustic profile for vocal emotion, sound intensity is frequently regarded as a control parameter in neurocognitive studies of vocal emotion, leaving its role and neural underpinnings unclear. To investigate these issues, we asked participants to rate the angry level of neutral and angry prosodies before and after sound intensity modification in Experiment 1, and recorded electroencephalogram (EEG) for mismatching emotional prosodies with and without sound intensity modification and for matching emotional prosodies while participants performed emotional feature or sound intensity congruity judgment in Experiment 2. It was found that sound intensity modification had significant effect on the rating of angry level for angry prosodies, but not for neutral ones. Moreover, mismatching emotional prosodies, relative to matching ones, induced enhanced N2/P3 complex and theta band synchronization irrespective of sound intensity modification and task demands. However, mismatching emotional prosodies with reduced sound intensity showed prolonged peak latency and decreased amplitude in N2/P3 complex and smaller theta band synchronization. These findings suggest that though it cannot categorically affect emotionality conveyed in emotional prosodies, sound intensity contributes to emotional significance quantitatively, implying that sound intensity should not simply be taken as a control parameter and its unique role needs to be specified in vocal emotion studies.

The integration of facial and vocal cues during emotional change perception: EEG markers

The ability to detect emotional changes is of primary importance for social living. Though emotional signals are often conveyed by multiple modalities, how emotional changes in vocal and facial modalities integrate into a unified percept has yet to be directly investigated. To address this issue, we asked participants to detect emotional changes delivered by facial, vocal and facial-vocal expressions while behavioral responses and electroencephalogram were recorded. Behavioral results showed that bimodal emotional changes were detected with higher accuracy and shorter response latencies compared with each unimodal condition. Moreover, the detection of emotional change, regardless of modalities, was associated with enhanced amplitudes in the N2 and P3 component, as well as greater theta synchronization. More importantly, the P3 amplitudes and theta synchronization were larger for the bimodal emotional change condition than for the sum of the two unimodal conditions. The superadditive responses in P3 amplitudes and theta synchronization were both positively correlated with the magnitude of the bimodal superadditivity in accuracy. These behavioral and electrophysiological data consistently illustrated an effect of audiovisual integration during the detection of emotional changes, which is most likely mediated by the P3 activity and theta oscillations in brain responses.

Topic Structure Affects Semantic Integration: Evidence from Event-Related Potentials

This study investigated whether semantic integration in discourse context could be influenced by topic structure using event-related brain potentials. Participants read discourses in which the last sentence contained a critical word that was either congruent or incongruent with the topic established in the first sentence. The intervening sentences between the first and the last sentence of the discourse either maintained or shifted the original topic. Results showed that incongruent words in topic-maintained discourses elicited an N400 effect that was broadly distributed over the scalp while those in topic-shifted discourses elicited an N400 effect that was lateralized to the right hemisphere and localized over central and posterior areas. Moreover, a late positivity effect was only elicited by incongruent words in topic-shifted discourses, but not in topic-maintained discourses. This suggests an important role for discourse structure in semantic integration, such that compared with topic-maintained discourses, the complexity of discourse structure in topic-shifted condition reduces the initial stage of semantic integration and enhances the later stage in which a mental representation is updated.

Different patterns of puberty effect in neural oscillation to negative stimuli: sex differences

The present study investigated the impact of puberty on sex differences in neural sensitivity to negative stimuli. Event-related oscillation technique was used. Because girls are more vulnerable to affective disturbances than boys during adolescence, it was hypothesized that puberty exerts different influences on neural sensitivity to negative stimuli in boys and girls. EEGs were recorded for highly negative (HN), mildly negative (MN) and neutral pictures, when boys and girls distinct in pubertal status performed a non-emotional distracting task. No emotion effect and its interaction with sex and puberty were observed in response latencies. However, puberty influenced the gamma-band oscillation effect for negative stimuli differently for boys and girls: Pre-pubertal boys showed a significant emotion effect for HN stimuli, whose size was decreased in pubertal boys. By contrast, there was a significant emotion effect for HN stimuli in pubertal girls but not in pre-pubertal girls. On the other hand, the size of the emotion effect for HN stimuli was similar for pre-pubertal boys and girls; while this effect was significantly more pronounced in pubertal girls compared to pubertal boys. Additionally, the size of the emotion effect in gamma oscillations decreased as a function of pubertal development during both HN and MN stimulation in boys. For girls, the emotion effect in gamma oscillations increased with pubertal development during HN stimulation. Thus, puberty is associated with reduced neural sensitivity in boys but increased sensitivity in girls, in reaction to negative stimuli. The implications of these results for the psychopathology during adolescence were discussed.

The electrocortical modulation effects of different emotion regulation strategies

The current event-related potential study investigated the modulation effects of different emotion regulation strategies on electrocortical responses. When watching negative or neutral pictures, participants were instructed to perform three tasks: cognitive reappraisal, expressive suppression and passive viewing. We found that negative pictures elicited a larger late positive potential (LPP) than neutral pictures. Moreover, processes involved in strategy also had an effect on LPP amplitude, which was indicated by a larger LPP in reappraisal compared with suppression and viewing tasks when neutral pictures were presented. After the influence of processes on LPP was excluded, results showed that reappraisal effectively decreased the emotion-enhanced LPP than suppression and viewing. The difference in regulatory effect may be determined by the underlying processing mechanism. A larger frontal-central component, N2, was observed in suppression than reappraisal and viewing, which suggested that it involved the processes focusing on behavioral response. While the larger LPP found in reappraisal implicated that it recruited cognitive processes focusing on the picture meaning.

Pleasure attainment or self-realization: the balance between two forms of well-beings are encoded in default mode network

Abstract What is a good life and how it can be achieved is one of the fundamental issues. When considering a good life, there is a division between hedonic (pleasure attainment) and eudaimonic well-being (meaning pursuing and self-realization). However, an integrated approach that can compare the brain functional and structural differences of these two forms of well-being is lacking. Here, we investigated how the individual tendency to eudaimonic well-being relative to hedonic well-being, measured using eudaimonic and hedonic balance (EHB) index, is reflected in the functional and structural features of a key network of well-being—the default mode network (DMN). We found that EHB was positively correlated with functional connectivity of bilateral ventral medial prefrontal cortex within anterior DMN and bilateral precuneus within posterior DMN. Brain morphometric analysis showed that EHB was also positively correlated with gray matter volume in left precuneus. These results demonstrated that the relative dominance of one form of well-being to the other is reflected in the morphometric characteristics and intrinsic functions of DMN.

How Distance Affects Semantic Integration in Discourse: Evidence from Event-Related Potentials

Event-related potentials were used to investigate whether semantic integration in discourse is influenced by the number of intervening sentences between the endpoints of integration. Readers read discourses in which the last sentence contained a critical word that was either congruent or incongruent with the information introduced in the first sentence. Furthermore, for the short discourses, the first and last sentence were intervened by only one sentence while for the long discourses, they were intervened by three sentences. We found that the incongruent words elicited an N400 effect for both the short and long discourses. However, a P600 effect was only observed for the long discourses, but not for the short ones. These results suggest that although readers can successfully integrate upcoming words into the existing discourse representation, the effort required for this integration process is modulated by the number of intervening sentences. Thus, discourse distance as measured by the number of intervening sentences should be taken as an important factor for semantic integration in discourse.