Neurophysiological and Behavioral Responses of Mandarin Lexical Tone Processing

Language experience enhances discrimination of speech contrasts at a behavioral- perceptual level, as well as at a pre-attentive level, as indexed by event-related potential (ERP) mismatch negativity (MMN) responses. The enhanced sensitivity could be the result of changes in acoustic resolution and/or long-term memory representations of the relevant information in the auditory cortex. To examine these possibilities, we used a short (ca. 600 ms) vs. long (ca. 2,600 ms) interstimulus interval (ISI) in a passive, oddball discrimination task while obtaining ERPs. These ISI differences were used to test whether cross-linguistic differences in processing Mandarin lexical tone are a function of differences in acoustic resolution and/or differences in long-term memory representations. Bisyllabic nonword tokens that differed in lexical tone categories were presented using a passive listening multiple oddball paradigm. Behavioral discrimination and identification data were also collected. The ERP results revealed robust MMNs to both easy and difficult lexical tone differences for both groups at short ISIs. At long ISIs, there was either no change or an enhanced MMN amplitude for the Mandarin group, but reduced MMN amplitude for the English group. In addition, the Mandarin listeners showed a larger late negativity (LN) discriminative response than the English listeners for lexical tone contrasts in the long ISI condition. Mandarin speakers outperformed English speakers in the behavioral tasks, especially under the long ISI conditions with the more similar lexical tone pair. These results suggest that the acoustic correlates of lexical tone are fairly robust and easily discriminated at short ISIs, when the auditory sensory memory trace is strong. At longer ISIs beyond 2.5 s language-specific experience is necessary for robust discrimination

Measuring Cross-Linguistic Influence in First- and Second-Generation Bilinguals: ERP vs. Acceptability Judgments

Two types of Spanish-English bilinguals were tested in an event-related potential (ERP) experiment on a contrast in the two languages exemplified in (1) and (2) in order to investigate linguistic permeability during processing of Spanish (1a and 2a). In Spanish, but not English, absence of the complementizer que is ungrammatical. (1) a. Qué hermana confesó Inés que había comido la tarta? b. *What sister did Inés confess that had eaten the cake? (2) a. *Qué hermana confesó Inés Ø había comido la tarta? b. What sister did Inés confess Ø had eaten the cake? In a first analysis, we grouped subjects by generation and compared ERP responses to que-less vs. que-full sentences. A significant N400 effect was found for first-, but not second-generation, suggesting reduced sensitivity to missing que for the latter. However, a second analysis, using linear mixed modeling to test predictiveness of individual speaker variables revealed generation to be non-predictive of N400 amplitude. Instead, current language use, cumulative exposure to English, and socioeconomic status (SES) were significant predictors for all subjects: increased English use, exposure, and SES resulted in smaller N400 amplitude to the anomaly in Spanish shown in (2a). Our results show that a priori classification of bilinguals masks gradient cross-linguistic effects, and processing is permeable in all bilinguals depending on amount of language use. Results from an acceptability judgment task administered to the same subjects using a subset of the same stimuli show that both subject groups judge que-less and que-full to be equally natural. These results suggest that behavioral measures that rely on metalinguistic judgments may not be good indicators of processing, and that having to appeal to metalinguistic knowledge may mask intrinsic knowledge

Neurophysiological indices of the effect of cognates on vowel perception in late Spanish-English bilinguals

It is well established that acquiring a second language (L2) later in life results in less accurate production and perception of speech sounds in the L2. Languages like Spanish and English have many common words (cognates) and similar sounds, learning how the combination of cognate status and sound similarity can affect processing and lexical access in an L2 is of interest to educators. In the present study, fifteen monolingual English-speakers and 15 late Spanish-English bilinguals were presented with Spanish-English cognates and non-cognates. Event related potentials (ERP) were used to determine whether late L2-learners had more difficulty discriminating mispronunciations of vowels in English words that have Spanish cognates compared to words that do not have cognates. Behavioral results indicated effects of language background differences, but not cognate status, on participants’ ability to discriminate mispronunciations of English vowels, with bilinguals showing poorer discrimination. ERP results revealed that cognate words facilitated L2 phonological processing as evidenced by a larger frontal positive component (P400) ERP effect, similar in amplitude to the P400 from monolinguals. Results suggest that cognate words facilitate not only vocabulary acquisition, but also speech processing, in adult L2 learners, and, thus, may also be useful as a tool for perceptual learning

Perception of American English Consonants /v/ and /w/ by Hindi Speakers of English

This study examined perception of the American English (AE) /v/-/w/ consonant contrast by Hindi speakers of English as a second language (L2). A second aim was to determine whether residence in the US modulated perception of this difficult contrast for proficient bilingual Hindi-English listeners. Two groups of Hindi-English bilinguals (the first resided in the US for more than five years, the second lived in India) and a group of AE-speaking listeners participated in the study. Listeners’ identification and discrimination of nonsense words (e.g., “vagag” vs. “wagag”) were examined. Hindi listeners performed significantly less accurately than AE controls. Accuracy by Hindi listeners was near chance for identification and higher-than-chance for discrimination. Exposure to AE in the US did not improve performance. These results are consistent with previous studies of late L2 learners and extend findings to a population that was proficient in an L2 before arriving in the L2 environment

Neural Indices of Vowel Discrimination in Monolingual and Bilingual Infants and Children

Objectives: To examine maturation of neural discriminative responses to an English vowel contrast from infancy to 4 years of age and to determine how biological factors (age and sex) and an experiential factor (amount of Spanish versus English input) modulate neural discrimination of speech. Design: Event-related potential (ERP) mismatch responses (MMRs) were used as indices of discrimination of the American English vowels [ε] versus [I] in infants and children between 3 months and 47 months of age. A total of 168 longitudinal and cross-sectional data sets were collected from 98 children (Bilingual Spanish–English: 47 male and 31 female sessions; Monolingual English: 48 male and 42 female sessions). Language exposure and other language measures were collected. ERP responses were examined in an early time window (160 to 360 msec, early MMR [eMMR]) and late time window (400 to 600 msec, late MMR). Results: The eMMR became more negative with increasing age. Language experience and sex also influenced the amplitude of the eMMR. Specifically, bilingual children, especially bilingual females, showed more negative eMMR compared with monolingual children and with males. However, the subset of bilingual children with more exposure to English than Spanish compared with those with more exposure to Spanish than English (as reported by caretakers) showed similar amplitude of the eMMR to their monolingual peers. Age was the only factor that influenced the amplitude of the late MMR. More negative late MMR was observed in older children with no difference found between bilingual and monolingual groups. Conclusions: Consistent with previous studies, our findings revealed that biological factors (age and sex) and language experience modulated the amplitude of the eMMR in young children. The early negative MMR is likely to be the mismatch negativity found in older children and adults. In contrast, the late MMR amplitude was influenced only by age and may be equivalent to the Nc in infants and to the late negativity observed in some auditory passive oddball designs

Existence of God: Antithetical Themes in “Dr. Faustus” and “Waiting for Godot”

This paper is about the antithetical themes regarding the existence of God in two plays “Doctor Faustus” by Christopher Marlow and “Waiting for Godot” by Samuel Backett. Both the plays represent two different ages and religious orientations. The former is a tragedy of a doctor of philosophy who pledges his soul with the Devil for the sake of attaining the power of necromancy in a flagrant disregard to God’s commandments and is damned to hellfire whereas the latter is tragicomedy that projects meaninglessness of life through characters questioning the very significance of God’s existence. Hence it is presumed that heterogeneous themes running parallel to each other might arouse different emotions in the reader. In order to examine whether such opposing themes in two different dramas exist or not, textual excerpts were analyzed, literature was reviewed, critics views were collected, and opinion of the experts in teaching literature were gathered. Finally, it is concluded that both the plays do have themes which run into opposite directions regarding the existence of God leading to the arousal of unlike emotions

Perturbing Dynamin Reveals Potent Effects on the Drosophila Circadian Clock

BACKGROUND: Transcriptional feedback loops are central to circadian clock function. However, the role of neural activity and membrane events in molecular rhythms in the fruit fly Drosophila is unclear. To address this question, we expressed a temperature-sensitive, dominant negative allele of the fly homolog of dynamin called shibire(ts1) (shi(ts1)), an active component in membrane vesicle scission. PRINCIPAL FINDINGS: Broad expression in clock cells resulted in unexpectedly long, robust periods (>28 hours) comparable to perturbation of core clock components, suggesting an unappreciated role of membrane dynamics in setting period. Expression in the pacemaker lateral ventral neurons (LNv) was necessary and sufficient for this effect. Manipulation of other endocytic components exacerbated shi(ts1)'s behavioral effects, suggesting its mechanism is specific to endocytic regulation. PKA overexpression rescued period effects suggesting shi(ts1) may downregulate PKA pathways. Levels of the clock component PERIOD were reduced in the shi(ts1)-expressing pacemaker small LNv of flies held at a fully restrictive temperature (29 degrees C). Less restrictive conditions (25 degrees C) delayed cycling proportional to observed behavioral changes. Levels of the neuropeptide PIGMENT-DISPERSING FACTOR (PDF), the only known LNv neurotransmitter, were also reduced, but PERIOD cycling was still delayed in flies lacking PDF, implicating a PDF-independent process. Further, shi(ts1) expression in the eye also results in reduced PER protein and per and vri transcript levels, suggesting that shibire-dependent signaling extends to peripheral clocks. The level of nuclear CLK, transcriptional activator of many core clock genes, is also reduced in shi(ts1) flies, and Clk overexpression suppresses the period-altering effects of shi(ts1). CONCLUSIONS: We propose that membrane protein turnover through endocytic regulation of PKA pathways modulates the core clock by altering CLK levels and/or activity. These results suggest an important role for membrane scission in setting circadian period

TRY plant trait database – enhanced coverage and open access

Plant traits - the morphological, anatomical, physiological, biochemical and phenological characteristics of plants - determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits - almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives