Neural correlates of lexical stress: Mismatch negativity reflects fundamental frequency and intensity

Neural correlates of lexical stress were studied using the mismatch negativity (MMN) component in event-related potentials. The MMN responses were expected to reveal the encoding of stress information into long-term memory and the contributions of prosodic features such as fundamental frequency (F0) and intensity toward lexical access. In a passive oddball paradigm, neural responses to changes in F0, intensity, and in both features together were recorded for words and pseudowords. The findings showed significant differences not only between words and pseudowords but also between prosodic features. Early processing of prosodic information in words was indexed by an intensity-related MMN and an F0-related P200. These effects were stable at right-anterior and mid-anterior regions. At a later latency, MMN responses were recorded for both words and pseudowords at the mid-anterior and posterior regions. The P200 effect observed for F0 at the early latency for words developed into an MMN response. Intensity elicited smaller MMN for pseudowords than for words. Moreover, a larger brain area was recruited for the processing of words than for the processing of pseudowords. These findings suggest earlier and higher sensitivity to prosodic changes in words than in pseudowords, reflecting a language-related process. The present study, therefore, not only establishes neural correlates of lexical stress but also confirms the presence of long-term memory traces for prosodic information in the brain

Perceptual Correlates of Turkish Word Stress and Their Contribution to Automatic Lexical Access: Evidence from Early ERP Components

Perceptual correlates of Turkish word stress and their contribution to lexical access were studied using the mismatch negativity (MMN) component in event-related potentials (ERPs). The MMN was expected to indicate if segmentally identical Turkish words were distinguished on the sole basis of prosodic features such as fundamental frequency (f0), spectral emphasis (SE), and duration. The salience of these features in lexical access was expected to be reflected in the amplitude of MMN responses. In a multi-deviant oddball paradigm, neural responses to changes in f0, SE, and duration individually, as well as to all three features combined, were recorded for words and pseudowords presented to 14 native speakers of Turkish. The word and pseudoword contrast was used to differentiate language-related effects from acoustic-change effects on the neural responses. First and in line with previous findings, the overall MMN was maximal over frontal and central scalp locations. Second, changes in prosodic features elicited neural responses both in words and pseudowords, confirming the brain's automatic response to any change in auditory input. However, there were processing differences between the prosodic features, most significantly in f0: While f0 manipulation elicited a slightly right-lateralized frontally-maximal MMN in words, it elicited a frontal P3a in pseudowords. Considering that P3a is associated with involuntary allocation of attention to salient changes, the manipulations of f0 in the absence of lexical processing lead to an intentional evaluation of pitch change. f0 is therefore claimed to be lexically specified in Turkish. Rather than combined features, individual prosodic features differentiate language-related effects from acoustic-change effects. The present study confirms that segmentally identical words can be distinguished on the basis of prosodic information alone, and establishes the salience of f0 in lexical access

First interim analysis of the GIDEON (Global Investigation of therapeutic DEcisions in hepatocellular carcinoma and Of its treatment with sorafeNib) non‐interventional study

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/92068/1/j.1742-1241.2012.02940.x.pd

Continuous Interaction with a Virtual Human

Attentive Speaking and Active Listening require that a Virtual Human be capable of simultaneous perception/interpretation and production of communicative behavior. A Virtual Human should be able to signal its attitude and attention while it is listening to its interaction partner, and be able to attend to its interaction partner while it is speaking – and modify its communicative behavior on-the-fly based on what it perceives from its partner. This report presents the results of a four week summer project that was part of eNTERFACE’10. The project resulted in progress on several aspects of continuous interaction such as scheduling and interrupting multimodal behavior, automatic classification of listener responses, generation of response eliciting behavior, and models for appropriate reactions to listener responses. A pilot user study was conducted with ten participants. In addition, the project yielded a number of deliverables that are released for public access

Lexical and information structure functions of prosody and their relevance for spoken communication: Evidence from psychometric and electroencephalographic data

Prosody not only distinguishes “lexical” meaning but also plays a key role in information packaging by highlighting the most relevant constituent of the discourse, namely, “focus” information. The present study investigated the role of lexical and focus functions of prosody in the coherent interpretation of linguistic input. To this end, we manipulated the correctness of prosodic markers in the context and scrutinized how listeners evaluate these violations—whether they result in lexical or focus anomalies—using psychometric and EEG measures. Psychometric data from 40 participants indicated that prosodic violations were judged as incorrect by the listeners both at the lexical and focus levels, with focus level violations leading to lower correctness scores than lexical level violations, and combined violations receiving the lowest scores. EEG data from 20 participants documented a strong N400 effect (350–550 msec) in response to combined violations, and a late posterior negativity (600–900 msec) present only for combined violations and focus-level violations. Consistent with the psychometric data, the EEG data suggest that prosodic violations at the focus level result in higher costs for comprehension than prosodic violations at the lexical level, whereas combined prosodic violations most significantly disrupt the interpretation. Taken together, these findings suggest that the language comprehension system is sensitive to accurate representations of both lexical and information structure prosody, and benefits from the interaction between them; however, they are weighted differently based on their relevance for a functioning spoken communication

Functional roles of Swedish pitch accents and their phonological and cognitive markedness

In Swedish, words are associated with either of two pitch contours labelled as Accent 1 and Accent 2. At least one of them is taken to be phonologically and cognitively marked. Besides encoding lexical tonal distinctions, these accents reflect intonational prominence. Drawing on data from psychometric and electroencephalographic (EEG) measures, we scrutinized the functional load of the accents for the processing of linguistic input, and explored any potential processing differences between Accent 1 and Accent 2. Experimental stimuli consisted of one hundred sets of auditory dialogues, where test words were accented either appropriately or inappropriately within their respective contexts. Native speakers of Central Swedish were tasked with judging the correctness of sentences containing the test words, actively in the psychometric paradigm and passively in the EEG paradigm. Psychometric data from forty participants revealed that accent violations exerted a statistically significant negative impact on correctness judgements. Both Accent 1 and Accent 2 violations were deemed as incorrect by the listeners, indicating that listeners use both of them to arrive at the correct interpretation of the linguistic input. Moreover, there was a statistically significant difference in the perceived correctness of violations depending on the accent pattern. Accent 2 violations received a lower rating for correctness in comparison to Accent 1 violations, suggesting that listeners show more sensitivity to accent violations in Accent 2 words than in Accent 1 words. EEG data from twenty participants were in accordance with the psychometric data, and documented larger negative ERP responses, observed at both early and later latencies, to Accent 2 violations compared to Accent 1 violations, reflecting neurocognitive difficulty associated with the processing of linguistic input. Put differently, the application of wrong accent pattern for Accent 2 words resulted in higher costs for spoken communication than Accent 1 words, which is in line with the notion that Accent 2 is marked both phonologically and cognitively in Central Swedish. This pattern of results provides evidence that the brain not only extracts and utilizes pitch accents for a coherent interpretation of the linguistic input but also treats them differently depending on their phonological and cognitive markedness

The role of pitch accent in discourse comprehension and the markedness of Accent 2 in Central Swedish.

In Swedish, words are associated with either of two pitch contours known as Accent 1 and Accent 2. Using a psychometric test, we investigated how listeners judge pitch accent violations while interpreting discourse. Forty native speakers of Central Swedish were presented with auditory dialogues, where test words were appropriately or inappropriately accented in a given context, and asked to judge the correctness of sentences containing the test words. Data indicated a statistically significant effect of wrong accent pattern on the correctness judgment. Both Accent 1 and Accent 2 violations interfered with the coherent interpretation of discourse and were judged as incorrect by the listeners. Moreover, there was a statistically significant difference in the perceived correctness between the accent patterns. Accent 2 violations led to a lower correctness score compared to Accent 1 violations, indicating that the listeners were more sensitive to pitch accent violations in Accent 2 words than in Accent 1 words. This result is in line with the notion that Accent 2 is marked and lexically represented in Central Swedish. Taken together, these findings indicate that listeners use both Accent 1 and Accent 2 to arrive at the correct interpretation of the linguistic input, while assigning varying degrees of relevance to them depending on their markedness

Investigating Prosodic Accommodation in Clinical Interviews with Depressed Patients

Six in-depth clinical interviews, involving six elderly female patients (aged 60+) and one female psychiatrist, were recorded and analysed for a number of prosodic accommodation variables. Our analysis focused on pitch, speaking time, and vowel-space ratio. Findings indicate that there is a dynamic manifestation of prosodic accommodation over the course of the interactions. There is clear adaptation on the part of the psychiatrist, even going so far as to have a reduced vowel-space ratio, mirroring a reduced vowel-space ratio in the depressed patients. Previous research has found a reduced vowel-space ratio to be associated with psychological distress; however, we suggest that it indicates a high level of adaptation on the part of the psychiatrist and needs to be considered when analysing psychiatric clinical interactions