Publications

Abstract

This study investigated the perception of American English phonemes by native listeners. Listeners identified either the consonant or the vowel in all possible English CV and VC syllables. The syllables were embedded in multispeaker babble at three signal-to-noise ratios (0 dB, 8 dB, and 16 dB). Effects of syllable position, signal-to-noise ratio, and articulatory features on vowel and consonant identification are discussed. The results constitute the largest source of data that is currently available on phoneme confusion patterns of American English phonemes by native listeners.

Abstract

This study investigated the perception of American English phonemes by native listeners. Listeners identified either the consonant or the vowel in all possible English CV and VC syllables. The syllables were embedded in multispeaker babble at three signalto-noise ratios (0 dB, 8 dB, and 16 dB). Effects of syllable position, signal-to-noise ratio, and articulatory features on vowel and consonant identification are discussed. The results constitute the largest source of data that is currently available on phoneme confusion patterns of American English phonemes by native listeners.

Abstract

The extreme case of perceptual similarity is indiscriminability, as when two second‐language phonemes map to a single native category. An example is the English had‐head vowel contrast for Dutch listeners; Dutch has just one such central vowel, transcribed [E]. We examine whether the failure to discriminate in phonetic categorization implies indiscriminability in other—e.g., lexical—processing. Eyetracking experiments show that Dutch‐native listeners instructed in English to ‘‘click on the panda’’ look (significantly more than native listeners) at a pictured pencil, suggesting that pan‐ activates their lexical representation of pencil. The reverse, however, is not the case: ‘‘click on the pencil’’ does not induce looks to a panda, suggesting that pen‐ does not activate panda in the lexicon. Thus prelexically undiscriminated second‐language distinctions can nevertheless be maintained in stored lexical representations. The problem of mapping a resulting unitary input to two distinct categories in lexical representations is solved by allowing input to activate only one second‐language category. For Dutch listeners to English, this is English [E], as a result of which no vowels in the signal ever map to words containing [ae]. We suggest that the choice of category is here motivated by a more abstract, phonemic, metric of similarity.

Abstract

This study investigates the influence of both phonotactic and acoustic cues on the segmentation of spoken English. Listeners detected embedded English words in nonsense sequences (word spotting). Words aligned with phonotactic boundaries were easier to detect than words without such alignment. Acoustic cues to boundaries could also have signaled word boundaries, especially when word onsets lacked phonotactic alignment. However, only one of several durational boundary cues showed a marginally significant correlation with response times (RTs). The results suggest that word segmentation in English is influenced primarily by phonotactic constraints and only secondarily by acoustic aspects of the speech signal.

Abstract

A longstanding question in bilingualism is whether syntactic information is shared between the two language processing systems. We used an fMRI repetition suppression paradigm to investigate syntactic priming in reading comprehension in German–English late-acquisition bilinguals. In comparison to conventional subtraction analyses in bilingual experiments, repetition suppression has the advantage of being able to detect neuronal populations that are sensitive to properties that are shared by consecutive stimuli. In this study, we manipulated the syntactic structure between prime and target sentences. A sentence with a passive sentence structure in English was preceded either by a passive or by an active sentence in English or German. We looked for repetition suppression effects in left inferior frontal, left precentral and left middle temporal regions of interest. These regions were defined by a contrast of all non-target sentences in German and English versus the baseline of sentence-format consonant strings. We found decreases in activity (repetition suppression effects) in these regions of interest following the repetition of syntactic structure from the first to the second language and within the second language.
Moreover, a separate behavioural experiment using a word-by-word reading paradigm similar to the fMRI experiment showed faster reading times for primed compared to unprimed English target sentences regardless of whether they were preceded by an English or a German sentence of the same structure.
We conclude that there is interaction between the language processing systems and that at least some syntactic information is shared between a bilingual's languages with similar syntactic structures.

Abstract

Lexical recognition is typically slower in L2 than in L1. Part of the difficulty comes from a not precise enough processing of L2 phonemes. Consequently, L2 listeners fail to eliminate candidate words that L1 listeners can exclude from competing for recognition. For instance, the inability to distinguish /r/ from /l/ in rocket and locker makes for Japanese listeners both words possible candidates when hearing their onset (e.g., Cutler, Weber, and Otake, 2006). The L2 disadvantage can, however, be dispelled: For L2 listeners, but not L1 listeners, L2 speech from a non-native talker with the same language background is known to be as intelligible as L2 speech from a native talker (e.g., Bent and Bradlow, 2003). A reason for this may be that L2 listeners have ample experience with segmental deviations that are characteristic for their own accent. On this account, only phonemic deviations that are typical for the listeners’ own accent will cause spurious lexical activation in L2 listening (e.g., English magic pronounced as megic for Dutch listeners). In this talk, I will present evidence from cross-modal priming studies with a variety of L2 listener groups, showing how the processing of phonemic deviations is accent-specific but withstands fine phonetic differences.

Abstract

Previous research has shown that listeners make use of their knowledge of phonotactic constraints to segment speech into individual words. The present study investigates the influence of phonotactics when segmenting a non-native language. German and English listeners detected embedded English words in nonsense sequences. German listeners also had knowledge of English, but English listeners had no knowledge of German. Word onsets were either aligned with a syllable boundary or not, according to the phonotactics of the two languages. Words aligned with either German or English phonotactic boundaries were easier for German listeners to detect than words without such alignment. Responses of English listeners were influenced primarily by English phonotactic alignment. The results suggest that both native and non-native phonotactic constraints influence lexical segmentation of a non-native, but familiar, language.

Abstract

Reports of an advantage of bilingualism on brain structure in young adult participants
are inconsistent. Abutalebi et al. (2012) reported more efficient monitoring of conflict during the
Flanker task in young bilinguals compared to young monolingual speakers. The present study
compared young adult (mean age = 24) Cantonese-English bilinguals in Hong Kong and young
adult monolingual speakers. We expected (a) differences in metabolites in neural tissue to result
from bilingual experience, as measured by 1H-MRS at 3T, (b) correlations between metabolic
levels and Flanker conflict and interference effects (c) different associations in bilingual and
monolingual speakers. We found evidence of metabolic differences in the ACC due to bilingualism,
specifically in metabolites Cho, Cr, Glx and NAA. However, we found no significant correlations
between metabolic levels and conflict and interference effects and no significant evidence of
differential relationships between bilingual and monolingual speakers. Furthermore, we found no
evidence of significant differences in the mean size of conflict and interference effects between
groups i.e. no bilingual advantage. Lower levels of Cho, Cr, Glx and NAA in bilingual adults
compared to monolingual adults suggest that the brains of bilinguals develop greater adaptive
control during conflict monitoring because of their extensive bilingual experience.

Abstract

Many explanations of the difficulties associated with interpreting object relative clauses appeal to the demands that object relatives make on working memory. MacDonald and Christiansen [MacDonald, M. C., & Christiansen, M. H. (2002). Reassessing working memory: Comment on Just and Carpenter (1992) and Waters and Caplan (1996). Psychological Review, 109, 35-54] pointed to variations in reading experience as a source of differences, arguing that the unique word order of object relatives makes their processing more difficult and more sensitive to the effects of previous experience than the processing of subject relatives. This hypothesis was tested in a large-scale study manipulating reading experiences of adults over several weeks. The group receiving relative clause experience increased reading speeds for object relatives more than for subject relatives, whereas a control experience group did not. The reading time data were compared to performance of a computational model given different amounts of experience. The results support claims for experience-based individual differences and an important role for statistical learning in sentence comprehension processes.

Abstract

Three experiments were designed to examine the effect on picture naming of the prior production of a word related in phonological form. In Experiment 1, the latency to produce Dutch words in response to pictures (e.g., hoed , hat) was longer following the production of a form-related word (e.g., hond , dog) in response to a definition on a preceding trial, than when the preceding definition elicited an unrelated word (e.g., kerk , church). Experiment 2 demonstrated that the inhibitory effect disappears when one unrelated word is produced intervening prime and target productions (e.g., hond-kerk-hoed ). The size of the inhibitory effect was not significantly affected by the frequency of the prime words or the target picture names. In Experiment 3, facilitation was observed for word pairs that shared offset segments (e.g., kurk-jurk , cork-dress), whereas inhibition was observed for shared onset segments (e.g., bloed-bloem , blood-flower). However, no priming was observed for prime and target words with shared phonemes but no mismatching segments (e.g., oom-boom , uncle-tree; hex-hexs , fence-witch). These findings are consistent with a process of phoneme competition during phonological encoding.

Abstract

If motor imagery uses neural structures involved in action execution, then the neural correlates of imagining an action should differ between individuals who tend to execute the action differently. Here we report fMRI data showing that motor imagery is influenced by the way people habitually perform motor actions with their particular bodies; that is, motor imagery is ‘body-specific’ (Casasanto, 2009). During mental imagery for complex hand actions, activation of cortical areas involved in motor planning and execution was left-lateralized in right-handers but right-lateralized in left-handers. We conclude that motor imagery involves the generation of an action plan that is grounded in the participant’s motor habits, not just an abstract representation at the level of the action’s goal. People with different patterns of motor experience form correspondingly different neurocognitive representations of imagined actions.

Abstract

Several studies indicate that both posterior superior temporal sulcus/middle temporal gyrus (pSTS/MTG) and left inferior frontal gyrus (LIFG) are involved in integrating information from different modalities. Here we investigated the respective roles of these two areas in integration of action and language information. We exploited the fact that the semantic relationship between language and different forms of action (i.e. co-speech gestures and pantomimes) is radically different. Speech and co-speech gestures are always produced together, and gestures are not unambiguously understood without speech. On the contrary, pantomimes are not necessarily produced together with speech and can be easily understood without speech. We presented speech together with these two types of communicative hand actions in matching or mismatching combinations to manipulate semantic integration load. Left and right pSTS/MTG were only involved in semantic integration of speech and pantomimes. Left IFG on the other hand was involved in integration of speech and co-speech gestures as well as of speech and pantomimes. Effective connectivity analyses showed that depending upon the semantic relationship between language and action, LIFG modulates activation levels in left pSTS.

This suggests that integration in pSTS/MTG involves the matching of two input streams for which there is a relatively stable common object representation, whereas integration in LIFG is better characterized as the on-line construction of a new and unified representation of the input streams. In conclusion, pSTS/MTG and LIFG are differentially involved in multimodal integration, crucially depending upon the semantic relationship between the input streams.

Abstract

It has been argued that we map observed actions onto our own motor system. Here we added to this issue by investigating whether hand preference influences the neural correlates of action observation of simple, essentially meaningless hand actions. Such an influence would argue for an intricate neural coupling between action production and action observation, which goes beyond effects of motor repertoire or explicit motor training, as has been suggested before. Indeed, parts of the human motor system exhibited a close coupling between action production and action observation. Ventral premotor and inferior and superior parietal cortices showed differential activation for left- and right-handers that was similar during action production as well as during action observation. This suggests that mapping observed actions onto the observer's own motor system is a core feature of action observation - at least for actions that do not have a clear goal or meaning. Basic differences in the way we act upon the world are not only reflected in neural correlates of action production, but can also influence the brain basis of action observation.

Abstract

Background

The biological mechanisms of headache chronification are poorly understood. We aimed to identify changes in DNA methylation associated with the transformation from episodic to chronic headache.
Methods

Participants were recruited from the population-based Norwegian HUNT Study. Thirty-six female headache patients who transformed from episodic to chronic headache between baseline and follow-up 11 years later were matched against 35 controls with episodic headache. DNA methylation was quantified at 485,000 CpG sites, and changes in methylation level at these sites were compared between cases and controls by linear regression analysis. Data were analyzed in two stages (Stages 1 and 2) and in a combined meta-analysis.
Results

None of the top 20 CpG sites identified in Stage 1 replicated in Stage 2 after multiple testing correction. In the combined meta-analysis the strongest associated CpG sites were related to SH2D5 and NPTX2, two brain-expressed genes involved in the regulation of synaptic plasticity. Functional enrichment analysis pointed to processes including calcium ion binding and estrogen receptor pathways.
Conclusion

In this first genome-wide study of DNA methylation in headache chronification several potentially implicated loci and processes were identified. The study exemplifies the use of prospectively collected population cohorts to search for epigenetic mechanisms of disease

Abstract

Researchers have suggested that the vocabularies of languages are oriented towards the communicative needs of language users. Here, we provide evidence demonstrating that the higher frequency of visual words in a large variety of English corpora is reflected in greater lexical differentiation—a greater number of unique words—for the visual domain in the English lexicon. In comparison, sensory modalities that are less frequently talked about, particularly taste and smell, show less lexical differentiation. In addition, we show that even though sensory language can be expected to change across historical time and between contexts of use (e.g., spoken language versus fiction), the pattern of visual dominance is a stable property of the English language. Thus, we show that across the board, precisely those semantic domains that are more frequently talked about are also more lexically differentiated, for perceptual experiences. This correlation between type and token frequencies suggests that the sensory lexicon of English is geared towards communicative efficiency.

Abstract

Spinocerebellar ataxia type 14 (SCA14) is a subtype of the autosomal dominant cerebellar ataxias that is characterized by slowly progressive cerebellar dysfunction and neurodegeneration. SCA14 is caused by mutations in the PRKCG gene, encoding protein kinase C gamma (PKCγ). Despite the identification of 40 distinct disease-causing mutations in PRKCG, the pathological mechanisms underlying SCA14 remain poorly understood. Here we report the molecular neuropathology of SCA14 in post-mortem cerebellum and in human patient-derived induced pluripotent stem cells (iPSCs) carrying two distinct SCA14 mutations in the C1 domain of PKCγ, H36R and H101Q. We show that endogenous expression of these mutations results in the cytoplasmic mislocalization and aggregation of PKCγ in both patient iPSCs and cerebellum. PKCγ aggregates were not efficiently targeted for degradation. Moreover, mutant PKCγ was found to be hyper-activated, resulting in increased substrate phosphorylation. Together, our findings demonstrate that a combination of both, loss-of-function and gain-of-function mechanisms are likely to underlie the pathogenesis of SCA14, caused by mutations in the C1 domain of PKCγ. Importantly, SCA14 patient iPSCs were found to accurately recapitulate pathological features observed in post-mortem SCA14 cerebellum, underscoring their potential as relevant disease models and their promise as future drug discovery tools.

Abstract

Set is widely used as a kind of basic data structure. However, when it is used for large scale data set the cost of storage, search and transport is overhead. The bloom filter uses a fixed size bit string to represent elements in a static set, which can reduce storage space and search cost that is a fixed constant. The time-space efficiency is achieved at the cost of a small probability of false positive in membership query. However, for many applications the space savings and locating time constantly outweigh this drawback. Dynamic bloom filter (DBF) can support concisely representation and approximate membership queries of dynamic set instead of static set. It has been proved that DBF not only possess the advantage of standard bloom filter, but also has better features when dealing with dynamic set. This paper proposes a time-dependent multiple bit-strings bloom filter (TMBF) which roots in the DBF and targets on dynamic incremental set. TMBF uses multiple bit-strings in time order to present a dynamic increasing set and uses backward searching to test whether an element is in a set. Based on the system logs from a real P2P file sharing system, the evaluation shows a 20% reduction in searching cost compared to DBF.

Abstract

Electroencephalography (EEG) provides high temporal resolution cognitive information from non-invasive recordings. However, one of the common practices-using a subset of sensors in ERP analysis is hard to provide a holistic and precise dynamic results. Selecting or grouping subsets of sensors may also be subject to selection bias, multiple comparison, and further complicated by individual differences in the group-level analysis. More importantly, changes in neural generators and variations in response magnitude from the same neural sources are difficult to separate, which limit the capacity of testing different aspects of cognitive hypotheses. We introduce EasyEEG, a toolbox that includes several multivariate analysis methods to directly test cognitive hypotheses based on topographic responses that include data from all sensors. These multivariate methods can investigate effects in the dimensions of response magnitude and topographic patterns separately using data in the sensor space, therefore enable assessing neural response dynamics. The concise workflow and the modular design provide user-friendly and programmer-friendly features. Users of all levels can benefit from the open-sourced, free EasyEEG to obtain a straightforward solution for efficient processing of EEG data and a complete pipeline from raw data to final results for publication.

Abstract

This article provides a first overview of some striking grammatical structures in Türk Idotscedilaret Dili (Turkish Sign Language, TID), the sign language used by the Deaf community in Turkey. The data are described with a typological perspective in mind, focusing on aspects of TID grammar that are typologically unusual across sign languages. After giving an overview of the historical, sociolinguistic and educational background of TID and the language community using this sign language, five domains of TID grammar are investigated in detail. These include a movement derivation signalling completive aspect, three types of nonmanual negation — headshake, backward head tilt, and puffed cheeks — and their distribution, cliticization of the negator NOT to a preceding predicate host sign, an honorific whole-entity classifier used to refer to humans, and a question particle, its history and current status in the language. A final evaluation points out the significance of these data for sign language research and looks at perspectives for a deeper understanding of the language and its history.

Abstract

Although bilingual speakers are very good at selectively using one language rather than another, sometimes language selection errors occur. To investigate how bilinguals monitor their speech errors and control their languages in use, we recorded event-related potentials (ERPs) in unbalanced Dutch-English bilingual speakers in a cued language-switching task. We tested the conflict-based monitoring model of Nozari and colleagues by investigating the error-related negativity (ERN) and comparing the effects of the two switching directions (i.e., to the first language, L1 vs. to the second language, L2). Results show that the speakers made more language selection errors when switching from their L2 to the L1 than vice versa. In the EEG, we observed a robust ERN effect following language selection errors compared to correct responses, reflecting monitoring of speech errors. Most interestingly, the ERN effect was enlarged when the speakers were switching to their L2 (less conflict) compared to switching to the L1 (more conflict). Our findings do not support the conflict-based monitoring model. We discuss an alternative account in terms of error prediction and reinforcement learning.

Abstract

Although bilingual speakers are very good at selectively using one language rather than another, sometimes language selection errors occur. We examined the relative contribution of top-down cognitive control and bottom-up language priming to these errors. Unbalanced Dutch-English bilinguals named pictures and were cued to switch between languages under time pressure. We also manipulated the number of same-language trials before a switch (long vs. short runs). Results show that speakers made more language selection errors when switching from their second language (L2) to the first language (L1) than vice versa. Furthermore, they made more errors when switching to the L1 after a short compared to a long run of L2 trials. In the reverse switching direction (L1 to L2), run length had no effect. These findings are most compatible with an account of language selection errors that assigns a strong role to top-down processes of cognitive control.

Abstract

It is undisputed that presenting a rhythmic stimulus leads to a measurable brain response that follows the rhythmic structure of this stimulus. What is still debated, however, is the question whether this brain response exclusively reflects a regular repetition of evoked responses, or whether it also includes entrained oscillatory activity. Here we systematically present evidence in favor of an involvement of entrained neural oscillations in the processing of rhythmic input while critically pointing out which questions still need to be addressed before this evidence could be considered conclusive. In this context, we also explicitly discuss the potential functional role of such entrained oscillations, suggesting that these stimulus-aligned oscillations reflect, and serve as, predictive processes, an idea often only implicitly assumed in the literature.

Abstract

The Corpus NGT