Publications

Abstract

One of the best-known types of non-independence between languages is caused by genealogical relationships due to descent from a common ancestor. These can be represented by (more or less resolved and controversial) language family trees. In theory, one can argue that language families should be built through the strict application of the comparative method of historical linguistics, but in practice this is not always the case, and there are several proposed classifications of languages into language families, each with its own advantages and disadvantages. A major stumbling block shared by most of them is that they are relatively difficult to use with computational methods, and in particular with phylogenetics. This is due to their lack of standardization, coupled with the general non-availability of branch length information, which encapsulates the amount of evolution taking place on the family tree. In this paper I introduce a method (and its implementation in R) that converts the language classifications provided by four widely-used databases (Ethnologue, WALS, AUTOTYP and Glottolog) intothe de facto Newick standard generally used in phylogenetics, aligns the four most used conventions for unique identifiers of linguistic entities (ISO 639-3, WALS, AUTOTYP and Glottocode), and adds branch length information from a variety of sources (the tree's own topology, an externally given numeric constant, or a distance matrix). The R scripts, input data and resulting Newick trees are available under liberal open-source licenses in a GitHub repository (https://github.com/ddediu/lgfam-newick), to encourage and promote the use of phylogenetic methods to investigate linguistic diversity and its temporal dynamics.

Abstract

The Recent Out-of-Africa human evolutionary model seems to be generally accepted. This impression is very prevalent outside palaeoanthropological circles (including studies of language evolution), but proves to be unwarranted. This paper offers a short review of the main challenges facing ROA and concludes that alternative models based on the concept of metapopulation must be also considered. The implications of such a model for language evolution and diversity are briefly reviewed.

Abstract

Here we re-evaluate our 2013 paper on the antiquity of language (Dediu and Levinson, 2013) in the light of a surge of new information on human evolution in the last half million years. Although new genetic data suggest the existence of some cognitive differences between Neanderthals and modern humans — fully expected after hundreds of thousands of years of partially separate evolution, overall our claims that Neanderthals were fully articulate beings and that language evolution was gradual are further substantiated by the wealth of new genetic, paleontological and archeological evidence briefly reviewed here.

Abstract

In this article we investigate the relation between discourse markers and turn-transition strategies in face-to-face conversations and Instant Messaging (IM), that is, unplanned, real-time, text-based, computer-mediated communication. By means of a quantitative corpus study of utterances containing a discourse marker, we show that utterance-final discourse markers are used more often in IM than in face-to-face conversations. Moreover, utterance-final discourse markers are shown to occur more often at points of turn-transition compared with points of turn-maintenance in both types of conversation. From our results we conclude that the discourse markers in utterance-final position can function as a turn-transition mechanism, signaling that the turn is over and the floor is open to the hearer. We argue that this linguistic turn-taking strategy is essentially similar in face-to-face and IM communication. Our results add to the evidence that communication in IM is more like speech than like writing.

Abstract

Recurrent de novo variants in the TBR1 transcription factor are implicated in the etiology of sporadic autism spectrum disorders (ASD). Disruptions include missense variants located in the T-box DNA-binding domain and previous work has demonstrated that they disrupt TBR1 protein function. Recent screens of thousands of simplex families with sporadic ASD cases uncovered additional T-box variants in TBR1 but their etiological relevance is unclear. We performed detailed functional analyses of de novo missense TBR1 variants found in the T-box of ASD cases, assessing many aspects of protein function, including subcellular localization, transcriptional activity and protein-interactions. Only two of the three tested variants severely disrupted TBR1 protein function, despite in silico predictions that all would be deleterious. Furthermore, we characterized a putative interaction with BCL11A, a transcription factor that was recently implicated in a neurodevelopmental syndrome involving developmental delay and language deficits. Our findings enhance understanding of molecular functions of TBR1, as well as highlighting the importance of functional testing of variants that emerge from next-generation sequencing, to decipher their contributions to neurodevelopmental disorders like ASD.

Abstract

Desmet, Brysbaert, and De Baecke (2002a) showed that the production of relative clauses following two potential attachment hosts (e.g., ‘Someone shot the servant of the actress who was on the balcony’) was influenced by the animacy of the first host. These results were important because they refuted evidence from Dutch against experience-based accounts of syntactic ambiguity resolution, such as the tuning hypothesis. However, Desmet et al. did not provide direct evidence in favour of tuning, because their study focused on production and did not include reading experiments. In the present paper this line of research was extended. A corpus analysis and an eye-tracking experiment revealed that when taking into account lexical properties of the NP host sites (i.e., animacy and concreteness) the frequency pattern and the on-line comprehension of the relative clause attachment ambiguity do correspond. The implications for exposure-based accounts of sentence processing are discussed.

Abstract

Intellectual disability (ID) is a severe neurodevelopmental disorder with genetically heterogeneous causes. Large-scale sequencing has led to the identification of many gene-disrupting mutations; however, a substantial proportion of cases lack a molecular diagnosis. As such, there remains much to uncover for a complete understanding of the genetic underpinnings of ID. Genetic variants present in non-coding regions of the genome have been highlighted as potential contributors to neurodevelopmental disorders given their role in regulating gene expression. Nevertheless the functional characterization of non-coding variants remains challenging. We describe the identification and characterization of de novo non-coding variation in 3′UTR regulatory regions within an ID cohort of 50 patients. This cohort was previously screened for structural and coding pathogenic variants via CNV, whole exome and whole genome analysis. We identified 44 high-confidence single nucleotide non-coding variants within the 3′UTR regions of these 50 genomes. Four of these variants were located within predicted miRNA binding sites and were thus hypothesised to have regulatory consequences. Functional testing showed that two of the variants interfered with miRNA-mediated regulation of their target genes, AMD1 and FAIM. Both these variants were found in the same individual and their functional consequences may point to a potential role for such variants in intellectual disability.

Abstract

Understanding the genetic factors underlying neurodevelopmental and neuropsychiatric disorders is a major challenge given their prevalence and potential severity for quality of life. While large-scale genomic screens have made major advances in this area, for many disorders the genetic underpinnings are complex and poorly understood. To date the field has focused predominantly on protein coding variation, but given the importance of tightly controlled gene expression for normal brain development and disorder, variation that affects non-coding regulatory regions of the genome is likely to play an important role in these phenotypes. Herein we show the importance of 3 prime untranslated region (3'UTR) non-coding regulatory variants across neurodevelopmental and neuropsychiatric disorders. We devised a pipeline for identifying and functionally validating putatively pathogenic variants from next generation sequencing (NGS) data. We applied this pipeline to a cohort of children with severe specific language impairment (SLI) and identified a functional, SLI-associated variant affecting gene regulation in cells and post-mortem human brain. This variant and the affected gene (ARHGEF39) represent new putative risk factors for SLI. Furthermore, we identified 3′UTR regulatory variants across autism, schizophrenia and bipolar disorder NGS cohorts demonstrating their impact on neurodevelopmental and neuropsychiatric disorders. Our findings show the importance of investigating non-coding regulatory variants when determining risk factors contributing to neurodevelopmental and neuropsychiatric disorders. In the future, integration of such regulatory variation with protein coding changes will be essential for uncovering the genetic causes of complex neurological disorders and the fundamental mechanisms underlying health and disease

Abstract

In conversation, people regularly deal with problems of speaking, hearing, and understanding. We report on a cross-linguistic investigation of the conversational structure of other-initiated repair (also known as collaborative repair, feedback, requests for clarification, or grounding sequences). We take stock of formats for initiating repair across languages (comparable to English huh?, who?, y’mean X?, etc.) and find that different languages make available a wide but remarkably similar range of linguistic resources for this function. We exploit the patterned variation as evidence for several underlying concerns addressed by repair initiation: characterising trouble, managing responsibility, and handling knowledge. The concerns do not always point in the same direction and thus provide participants in interaction with alternative principles for selecting one format over possible others. By comparing conversational structures across languages, this paper contributes to pragmatic typology: the typology of systems of language use and the principles that shape them.

Abstract

Ideophones (also known as expressives or mimetics, and including onomatopoeia) have been systematically studied in linguistics since the 1850s, when they were first described as a lexical class of vivid sensory words in West-African languages. This paper surveys the research history of ideophones, from its roots in African linguistics to its fruits in general linguistics and typology around the globe. It shows that despite a recurrent narrative of marginalisation, work on ideophones has made an impact in many areas of linguistics, from theories of phonological features to typologies of manner and motion, and from sound symbolism to sensory language. Due to their hybrid nature as gradient vocal gestures that grow roots in discrete linguistic systems, ideophones provide opportunities to reframe typological questions, reconsider the role of language ideology in linguistic scholarship, and rethink the margins of language. With ideophones increasingly being brought into the fold of the language sciences, this review synthesises past theoretical insights and empirical findings in order to enable future work to build on them.

Abstract

How a system represents information tightly constrains the kinds of problems it can solve. Humans routinely solve problems that appear to require structured representations of stimulus properties and the relations between them. An account of how we might acquire such representations has central importance for theories of human cognition. We describe how a system can learn structured relational representations from initially unstructured inputs using comparison, sensitivity to time, and a modified Hebbian learning algorithm. We summarize how the model DORA (Discovery of Relations by Analogy) instantiates this approach, which we call predicate learning, as well as how the model captures several phenomena from cognitive development, relational reasoning, and language processing in the human brain. Predicate learning offers a link between models based on formal languages and models which learn from experience and provides an existence proof for how structured representations might be learned in the first place.

Abstract

A commentary on
Transcranial Magnetic Stimulation over Left Inferior Frontal and Posterior Temporal Cortex Disrupts Gesture-Speech Integration

by Zhao, W., Riggs, K., Schindler, I., and Holle, H. (2018). J. Neurosci. 10, 1748–1717. doi: 10.1523/JNEUROSCI.1748-17.2017

Abstract

Previous work revealed that visual semantic information conveyed by gestures can enhance degraded speech comprehension, but the mechanisms underlying these integration processes under adverse listening conditions remain poorly understood. We used MEG to investigate how oscillatory dynamics support speech–gesture integration when integration load is manipulated by auditory (e.g., speech degradation) and visual semantic (e.g., gesture congruency) factors. Participants were presented with videos of an actress uttering an action verb in clear or degraded speech, accompanied by a matching (mixing gesture + “mixing”) or mismatching (drinking gesture + “walking”) gesture. In clear speech, alpha/beta power was more suppressed in the left inferior frontal gyrus and motor and visual cortices when integration load increased in response to mismatching versus matching gestures. In degraded speech, beta power was less suppressed over posterior STS and medial temporal lobe for mismatching compared with matching gestures, showing that integration load was lowest when speech was degraded and mismatching gestures could not be integrated and disambiguate the degraded signal. Our results thus provide novel insights on how low-frequency oscillatory modulations in different parts of the cortex support the semantic audiovisual integration of gestures in clear and degraded speech: When speech is clear, the left inferior frontal gyrus and motor and visual cortices engage because higher-level semantic information increases semantic integration load. When speech is degraded, posterior STS/middle temporal gyrus and medial temporal lobe are less engaged because integration load is lowest when visual semantic information does not aid lexical retrieval and speech and gestures cannot be integrated.

Abstract

During face-to-face communication, listeners integrate speech with gestures. The semantic information conveyed by iconic gestures (e.g., a drinking gesture) can aid speech comprehension in adverse listening conditions. In this magnetoencephalography (MEG) study, we investigated the spatiotemporal neural oscillatory activity associated with gestural enhancement of degraded speech comprehension. Participants watched videos of an actress uttering clear or degraded speech, accompanied by a gesture or not and completed a cued-recall task after watching every video. When gestures semantically disambiguated degraded speech comprehension, an alpha and beta power suppression and a gamma power increase revealed engagement and active processing in the hand-area of the motor cortex, the extended language network (LIFG/pSTS/STG/MTG), medial temporal lobe, and occipital regions. These observed low- and high-frequency oscillatory modulations in these areas support general unification, integration and lexical access processes during online language comprehension, and simulation of and increased visual attention to manual gestures over time. All individual oscillatory power modulations associated with gestural enhancement of degraded speech comprehension predicted a listener's correct disambiguation of the degraded verb after watching the videos. Our results thus go beyond the previously proposed role of oscillatory dynamics in unimodal degraded speech comprehension and provide first evidence for the role of low- and high-frequency oscillations in predicting the integration of auditory and visual information at a semantic level.

Abstract

Native listeners neurally integrate iconic gestures with speech, which can enhance degraded speech comprehension. However, it is unknown how non-native listeners neurally integrate speech and gestures, as they might process visual semantic context differently than natives. We recorded EEG while native and highly-proficient non-native listeners watched videos of an actress uttering an action verb in clear or degraded speech, accompanied by a matching ('to drive'+driving gesture) or mismatching gesture ('to drink'+mixing gesture). Degraded speech elicited an enhanced N400 amplitude compared to clear speech in both groups, revealing an increase in neural resources needed to resolve the spoken input. A larger N400 effect was found in clear speech for non-natives compared to natives, but in degraded speech only for natives. Non-native listeners might thus process gesture more strongly than natives when speech is clear, but need more auditory cues to facilitate access to gestural semantic information when speech is degraded.

Abstract

This paper summarizes the results of a descriptive syntactic category analysis of child English no which reveals that young children use and represent no as a determiner and negatives like no pen as NPs, contra standard analyses.

Abstract

This paper presents the methods of language documentation as applied in the Awetí Language Documentation Project, one of the projects in the Documentation of Endangered Languages Programme (DOBES). It describes the steps of how a large digital corpus of annotated multi-media data is built. Special attention is devoted to the format of annotation of linguistic data. The Advanced Glossing format is presented and justified

Abstract

Conclusion In this study we have examined the evidence for the exact genetic position of the Awetí language in the large Tupí family, especially evidence for an internal classification of the larger branch of Tupí called “Mawetí-Guaraní” which comprises the Tupí-Guaraní family, Awetí and Sateré-Mawé. As it turns out, we did not find any clear example of an uncommon sound change which would have happened after the separation of the antecessor of one branch but before the split between the other two. There is some just probability that Awetí belongs somewhat closer to Tupí-Guaraní within Mawetí-Guaraní (configuration A in Table 1), but we did not find any conclusive evidence. All we have are some weak indications the majority of which, however, point in this direction: • a higher number of cognates found between Awetí and proto-Tupí-Guarani; • lexicostatistic results (number of cognates in a 100-item-word-list proposed by Swadesh); • loss of long vowels in Awetí and Tupí-Guaraní, but not in Sateré-Mawé; • some sound changes suggest that in the development to Awetí and to proto-Tupí-Guaraní velar segments changes to dental segments (cf. the discussion of the correspondence set j : t : w); • possibly some of the correspondence sets given in Table 20. We consider it to be too soon to conclude that there is a branch Awetí + Tupí-Guaraní of Mawetí-Guaraní, opposed to Sateré-Mawé, but if there is any grouping, this hypothesis is most promising. 29

Abstract

Biologically inspired spiking networks are an important tool to study the nature of computation and cognition in neural systems. In this work, we investigate the representational capacity of spiking networks engaged in an identity mapping task. We compare two schemes for encoding symbolic input, one in which input is injected as a direct current and one where input is delivered as a spatio-temporal spike pattern. We test the ability of networks to discriminate their input as a function of the number of distinct input symbols. We also compare performance using either membrane potentials or filtered spike trains as state variable. Furthermore, we investigate how the circuit behavior depends on the balance between excitation and inhibition, and the degree of synchrony and regularity in its internal dynamics. Finally, we compare different linear methods of decoding population activity onto desired target labels. Overall, our results suggest that even this simple mapping task is strongly influenced by design choices on input encoding, state-variables, circuit characteristics and decoding methods, and these factors can interact in complex ways. This work highlights the importance of constraining computational network models of behavior by available neurobiological evidence.

Abstract

Numerous studies in psychology, cognitive neuroscience and psycholinguistics have used pictures of objects as stimulus materials. Currently, authors engaged in cross-linguistic work or wishing to run parallel studies at multiple sites where different languages are spoken must rely on rather small sets of black-and-white or colored line drawings. These sets are increasingly experienced as being too limited. Therefore, we constructed a new set of 750 colored pictures of concrete concepts. This set, MultiPic, constitutes a new valuable tool for cognitive scientists investigating language, visual perception, memory and/or attention in monolingual or multilingual populations. Importantly, the MultiPic databank has been normed in six different European languages (British English, Spanish, French, Dutch, Italian and German). All stimuli and norms are freely available at http://www.bcbl.eu/databases/multipic

Abstract

While the importance of mental simulation during literary reading has long been recognized, we know little about the factors that determine when, what, and how much readers mentally simulate. Here we investigate the influence of a specific text characteristic, namely verb tense (present vs. past), on mental simulation during literary reading. Verbs usually denote the actions and events that take place in narratives and hence it is hypothesized that verb tense will influence the amount of mental simulation elicited in readers. Although the present tense is traditionally considered to be more “vivid”, this study is one of the first to experimentally assess this claim. We recorded eye-movements while subjects read stories in the past or present tense and collected data regarding self-reported levels of mental simulation, transportation and appreciation. We found no influence of tense on any of the offline measures. The eye-tracking data showed a slightly more complex pattern. Although we did not find a main effect of sensorimotor simulation content on reading times, we were able to link the degree to which subjects slowed down when reading simulation eliciting content to offline measures of attention and transportation, but this effect did not interact with the tense of the story. Unexpectedly, we found a main effect of tense on reading times per word, with past tense stories eliciting longer first fixation durations and gaze durations. However, we were unable to link this effect to any of the offline measures. In sum, this study suggests that tense does not play a substantial role in the process of mental simulation elicited by literary stories.

Abstract

Predictive language processing is often studied by measuring eye movements as participants look at objects on a computer screen while they listen to spoken sentences. The use of this variant of the visual world paradigm has shown that information encountered by a listener at a spoken verb can give rise to anticipatory eye movements to a target object, which is taken to indicate that people predict upcoming words. The ecological validity of such findings remains questionable, however, because these computer experiments used two-dimensional (2D) stimuli that are mere abstractions of real world objects. Here we present a visual world paradigm study in a three-dimensional (3D) immersive virtual reality environment. Despite significant changes in the stimulus material and the different mode of stimulus presentation, language-mediated anticipatory eye movements were observed. These findings thus indicate prediction of upcoming words in language comprehension in a more naturalistic setting where natural depth cues are preserved. Moreover, the results confirm the feasibility of using eye-tracking in rich and multimodal 3D virtual environments.

Abstract

Perceptual representations of phonemes are flexible and adapt rapidly to accommodate idiosyncratic articulation in the speech of a particular talker. This letter addresses whether such adjustments remain stable over time and under exposure to other talkers. During exposure to a story, listeners learned to interpret an ambiguous sound as [f] or [s]. Perceptual adjustments measured after 12 h were as robust as those measured immediately after learning. Equivalent effects were found when listeners heard speech from other talkers in the 12 h interval, and when they had the opportunity to consolidate learning during sleep.

Abstract

During listening to spoken language, the perceptual system needs to adapt frequently to changes in talkers, and thus to considerable interindividual variability in the articulation of a given speech sound. This thesis investigated a learning process which allows listeners to use stored lexical representations to modify the interpretation of a speech sound when a talker's articulation of that sound is consistently unclear or ambiguous. The questions that were addressed in this research concerned the robustness of such perceptual learning, a potential role for sleep, and whether learning is specific to the speech of one talker or, alternatively, generalises to other talkers. A further study aimed to identify the underlying functional neuroanatomy by using magnetic resonance imaging methods. The picture that emerged for lexically-guided perceptual learning is that learning occurs very rapidly, is highly specific, and remains remarkably robust both over time and under exposure to speech from other talkers.

Abstract

This chapter reviews the computational processes that are responsible for recognizing word forms in the speech stream. We outline the different stages in a processing hierarchy from the extraction of general acoustic features, through speech‐specific prelexical processes, to the retrieval and selection of lexical representations. We argue that two recurring properties of the system as a whole are abstraction and adaptability. We also present evidence for parallel processing of information on different timescales, more specifically that segmental material in the speech stream (its consonants and vowels) is processed in parallel with suprasegmental material (the prosodic structures of spoken words). We consider evidence from both psycholinguistics and neurobiology wherever possible, and discuss how the two fields are beginning to address common computational problems. The challenge for future research in speech perception will be to build an account that links these computational problems, through functional mechanisms that address them, to neurobiological implementation.

Abstract

The domain of the human body is an ideal focus for semantic typology, since the body is a physical universal and all languages have terms referring to its parts. Previous research on body part terms has depended on secondary sources (e.g. dictionaries), and has lacked sufficient detail or clarity for a thorough understanding of these terms’ semantics. The present special issue is the outcome of a collaborative project aimed at improving approaches to investigating the semantics of body part terms, by developing materials to elicit information that provides for cross-linguistic comparison. The articles in this volume are original fieldwork-based descriptions of terminology for parts of the body in ten languages. Also included are an elicitation guide and experimental protocol used in gathering data. The contributions provide inventories of body part terms in each language, with analysis of both intensional and extensional aspects of meaning, differences in morphological complexity, semantic relations among terms, and discussion of partonomic structure within the domain.

Abstract

This document is intended for use as an elicitation guide for the field linguist consulting with native speakers in collecting terms for parts of the body, and in the exploration of their semantics.

Abstract

Abstract: This paper reviews current discussion of the issue of just what is lost when a language dies. Special reference is made to the current situation in Laos, a country renowned for its considerable cultural and linguistic diversity. It focuses on the historical, anthropological and ecological knowledge that a language can encode, and the social and cultural consequences of the loss of such traditional knowledge when a language is no longer passed on. Finally, the article points out the paucity of studies and obstacles to field research on minority languages in Laos, which seriously hamper their documentation.

Abstract

This article presents a description of nominal expressions for parts of the human body conventionalised in Lao, a Southwestern Tai language spoken in Laos, Northeast Thailand, and Northeast Cambodia. An inventory of around 170 Lao expressions is listed, with commentary where some notability is determined, usually based on explicit comparison to the metalanguage, English. Notes on aspects of the grammatical and semantic structure of the set of body part terms are provided, including a discussion of semantic relations pertaining among members of the set of body part terms. I conclude that the semantic relations which pertain between terms for different parts of the body not only include part/whole relations, but also relations of location, connectedness, and general association. Calling the whole system a ‘partonomy’ attributes greater centrality to the part/whole relation than is warranted.

Abstract

Laos features a high level of linguistic diversity, with more than 70 languages from four different major language families (Tai, Mon-Khmer, Hmong-Mien, Tibeto-Burman). Mon-Khmer languages were spoken in Laos earlier than other languages, with incoming migrations by Tai speakers (c. 2000 years ago) and Hmong-Mien speakers (c. 200 years ago). There is widespread language contact and multilingualism in upland minority communities, while lowland-dwelling Lao speakers are largely monolingual. Lao is the official national language. Most minority languages are endangered, with a few exceptions (notably Hmong and Kmhmu). There has been relatively little linguistic research on languages of Laos, due to problems of both infrastructure and administration.

Abstract

One of the fundamental issues for a language is its capacity to express
argument structure unambiguously. This study presents evidence
for the emergence and the incremental development of these
basic mechanisms in a newly developing language, Central Taurus
Sign Language. Our analyses identify universal patterns in both the
emergence and development of these mechanisms and in languagespecific
trajectories.

Abstract

In mainstream phonology, contrastive properties, like stem-final voicing, are simply listed in the lexicon. This article reviews experimental evidence that such contrastive properties may be predictable to some degree and that the relevant statistically gradient generalizations form an inherent part of the grammar. The evidence comes from the underlying voice specification of stem-final obstruents in Dutch. Contrary to received wisdom, this voice specification is partly predictable from the obstruent’s manner and place of articulation and from the phonological properties of the preceding segments. The degree of predictability, which depends on the exact contents of the lexicon, directs speakers’ guesses of underlying voice specifications. Moreover, existing words that disobey the generalizations are disadvantaged by being recognized and produced more slowly and less accurately, also under natural conditions.We discuss how these observations can be accounted for in two types of different approaches to grammar, Stochastic Optimality Theory and exemplar-based modeling.

Abstract

Acoustic duration and degree of vowel reduction are known to correlate with a word’s frequency of occurrence. The present study broadens the research on the role of frequency in speech production to voice assimilation. The test case was regressive voice assimilation in Dutch. Clusters from a corpus of read speech were more often perceived as unassimilated in lower-frequency words and as either completely voiced regressive assimilation or, unexpectedly, as completely voiceless progressive assimilation in higher-frequency words. Frequency did not predict the voice classifications over and above important acoustic cues to voicing, suggesting that the frequency effects on the classifications were carried exclusively by the acoustic signal. The duration of the cluster and the period of glottal vibration during the cluster decreased while the duration of the release noises increased with frequency. This indicates that speakers reduce articulatory effort for higher-frequency words, with some acoustic cues signaling more voicing and others less voicing. A higher frequency leads not only to acoustic reduction but also to more assimilation.

Abstract

FOXP transcription factors play important roles in neurodevelopment, but little is known about how their transcriptional activity is regulated. FOXP proteins cooperatively regulate gene expression by forming homo- and hetero-dimers with each other. Physical associations with other transcription factors might also modulate the functions of FOXP proteins. However, few FOXP-interacting transcription factors have been identified so far. Therefore, we sought to discover additional transcription factors that interact with the brain-expressed FOXP proteins, FOXP1, FOXP2 and FOXP4, through affinity-purifications of protein complexes followed by mass spectrometry. We identified seven novel FOXP-interacting transcription factors (NR2F1, NR2F2, SATB1, SATB2, SOX5, YY1 and ZMYM2), five of which have well-established roles in cortical development. Accordingly, we found that these transcription factors are co-expressed with FoxP2 in the deep layers of the cerebral cortex and also in the Purkinje cells of the cerebellum, suggesting that they may cooperate with the FoxPs to regulate neural gene expression in vivo. Moreover, we demonstrated that etiological mutations of FOXP1 and FOXP2, known to cause neurodevelopmental disorders, severely disrupted the interactions with FOXP-interacting transcription factors. Additionally, we pinpointed specific regions within FOXP2 sequence involved in mediating these interactions. Thus, by expanding the FOXP interactome we have uncovered part of a broader neural transcription factor network involved in cortical development, providing novel molecular insights into the transcriptional architecture underlying brain development and neurodevelopmental disorders.

Abstract

Human language offers rich ways to track, compare, and engage the attentional and epistemic states of interlocutors. While this task is central to everyday communication, our knowledge of the cross-linguistic grammatical means that target such intersubjective coordination has remained basic. In two serialised papers, we introduce the term ‘engagement’ to refer to grammaticalised means for encoding the relative mental directedness of speaker and addressee towards an entity or state of affairs, and describe examples of engagement systems from around the world. Engagement systems express the speaker’s assumptions about the degree to which their attention or knowledge is shared (or not shared) by the addressee. Engagement categories can operate at the level of entities in the here-and-now (deixis), in the unfolding discourse (definiteness vs indefiniteness), entire event-depicting propositions (through markers with clausal scope), and even metapropositions (potentially scoping over evidential values). In this first paper, we introduce engagement and situate it with respect to existing work on intersubjectivity in language. We then explore the key role of deixis in coordinating attention and expressing engagement, moving through increasingly intercognitive deictic systems from those that focus on the the location of the speaker, to those that encode the attentional state of the addressee.

Abstract

Engagement systems encode the relative accessibility of an entity or state of affairs to the speaker and addressee, and are thus underpinned by our social cognitive capacities. In our first foray into engagement (Part 1), we focused on specialised semantic contrasts as found in entity-level deictic systems, tailored to the primal scenario for establishing joint attention. This second paper broadens out to an exploration of engagement at the level of events and even metapropositions, and comments on how such systems may evolve. The languages Andoke and Kogi demonstrate what a canonical system of engagement with clausal scope looks like, symmetrically assigning ‘knowing’ and ‘unknowing’ values to speaker and addressee. Engagement is also found cross-cutting other epistemic categories such as evidentiality, for example where a complex assessment of relative speaker and addressee awareness concerns the source of information rather than the proposition itself. Data from the language Abui reveal that one way in which engagement systems can develop is by upscoping demonstratives, which normally denote entities, to apply at the level of events. We conclude by stressing the need for studies that focus on what difference it makes, in terms of communicative behaviour, for intersubjective coordination to be managed by engagement systems as opposed to other, non-grammaticalised means.

Abstract

In contrast to the large amount of dual-task research investigating the coordination of a linguistic and a nonlinguistic
task, little research has investigated how two linguistic tasks are coordinated. However, such research
would greatly contribute to our understanding of how interlocutors combine speech planning and listening in
conversation. In three dual-task experiments we studied how participants coordinated the processing of an
auditory stimulus (S1), which was either a syllable or a tone, with selecting a name for a picture (S2). Two SOAs,
of 0 ms and 1000 ms, were used. To vary the time required for lexical selection and to determine when lexical
selection took place, the pictures were presented with categorically related or unrelated distractor words. In
Experiment 1 participants responded overtly to both stimuli. In Experiments 2 and 3, S1 was not responded to
overtly, but determined how to respond to S2, by naming the picture or reading the distractor aloud. Experiment
1 yielded additive effects of SOA and distractor type on the picture naming latencies. The presence of semantic
interference at both SOAs indicated that lexical selection occurred after response selection for S1. With respect to
the coordination of S1 and S2 processing, Experiments 2 and 3 yielded inconclusive results. In all experiments,
syllables interfered more with picture naming than tones. This is likely because the syllables activated phonological
representations also implicated in picture naming. The theoretical and methodological implications of the
findings are discussed.

Abstract

Objectives: Our goal was to assess MR image uniformity by investigating aspects influencing said uniformity via a method laid out by the National Electrical Manufacturers Association (NEMA).
Methods: Six metallic materials embedded in a glass phantom were scanned (i.e. Au, Ag, Al, Au-Ag-Pd alloy, Ti and Co-Cr alloy) as well as a reference image. Sequences included spin echo (SE) and gradient echo (GRE) scanned in three planes (i.e. axial, coronal, and sagittal). Moreover, three surface coil types (i.e. head and neck, Brain, and temporomandibular joint coils) and two image correction methods (i.e. surface coil intensity correction or SCIC, phased array uniformity enhancement or PURE) were employed to evaluate their effectiveness on image uniformity. Image uniformity was assessed using the National Electrical Manufacturers Association peak-deviation non-uniformity method.
Results: Results showed that temporomandibular joint coils elicited the least uniform image and brain coils outperformed head and neck coils when metallic materials were present. Additionally, when metallic materials were present, spin echo outperformed gradient echo especially for Co-Cr (particularly in the axial plane). Furthermore, both SCIC and PURE improved image uniformity compared to uncorrected images, and SCIC slightly surpassed PURE when metallic metals were present. Lastly, Co-Cr elicited the least uniform image while other metallic materials generally showed similar patterns (i.e. no significant deviation from images without metallic metals).
Conclusions: Overall, a quantitative understanding of the factors influencing MR image uniformity (e.g. coil type, imaging method, metal susceptibility, and post-hoc correction method) is advantageous to optimize image quality, assists clinical interpretation, and may result in improved medical and dental care.

Abstract

This article presents the ventriloquist paradigm, an innovative method for studying speech processing in dialogue whereby participants interact face-to-face with a confederate who, unbeknownst to them, communicates by playing pre-recorded speech. Results show that the paradigm convinces more participants that the speech is live than a setup without the face-to-face element, and it elicits more interactive conversation than a setup in which participants believe their partner is a computer. By reconciling the ecological validity of a conversational context with full experimental control over phonetic exposure, the paradigm offers a wealth of new possibilities for studying speech processing in interaction.

Abstract

Studies of dyslexia provide vital insights into the cognitive architecture underpinning both disordered and normal reading. It is well established that inherited factors contribute to dyslexia susceptibility, but only very recently has evidence emerged to implicate specific candidate genes. In this article, we provide an accessible overview of four prominent examples--DYX1C1, KIAA0319, DCDC2 and ROBO1--and discuss their relevance for cognition. In each case correlations have been found between genetic variation and reading impairments, but precise risk variants remain elusive. Although none of these genes is specific to reading-related neuronal circuits, or even to the human brain, they have intriguing roles in neuronal migration or connectivity. Dissection of cognitive mechanisms that subserve reading will ultimately depend on an integrated approach, uniting data from genetic investigations, behavioural studies and neuroimaging.

Abstract

The mysterious human propensity for acquiring speech and language has fascinated scientists for decades. A substantial body of evidence suggests that this capacity is rooted in aspects of neurodevelopment that are specified at the genomic level. Researchers have begun to identify genetic factors that increase susceptibility to developmental disorders of speech and language, thereby offering the first molecular entry points into neuronal mechanisms underlying human vocal communication. The identification of genetic variants influencing language acquisition facilitates the analysis of animal models in which the corresponding orthologs are disrupted. At face value, the situation raises aperplexing question: if speech and language are uniquely human, can any relevant insights be gained from investigations of gene function in other species? This chapter addresses the question using the example of FOXP2, a gene implicated in a severe monogenic speech and language disorder. FOXP2 encodes a transcription factor that is highly conserved in vertebrate species, both in terms of protein sequence and expression patterns. Current data suggest that an earlier version of this gene, present in the common ancestor of humans, rodents, and birds, was already involved in establishing neuronal circuits underlying sensory-motor integration and learning of complex motor sequences. This may have represented one of the factors providing a permissive neural environment for subsequent evolution of vocal learning. Thus, dissection of neuromolecular pathways regulated by Foxp2 in nonlinguistic species is a necessary prerequisite for understanding the role of the human version of the gene in speech and language.

Abstract

Between 2 and 5% of children who are otherwise unimpaired have significant difficulties in acquiring expressive and/or receptive language, despite adequate intelligence and opportunity. While twin studies indicate a significant role for genetic factors in developmental disorders of speech and language, the majority of families segregating such disorders show complex patterns of inheritance, and are thus not amenable for conventional linkage analysis. A rare exception is the KE family, a large three-generation pedigree in which approximately half of the members are affected with a severe speech and language disorder which appears to be transmitted as an autosomal dominant monogenic trait. This family has been widely publicised as suffering primarily from a defect in the use of grammatical suffixation rules, thus supposedly supporting the existence of genes specific to grammar. The phenotype, however, is broader in nature, with virtually every aspect of grammar and of language affected. In addition, affected members have a severe orofacial dyspraxia, and their speech is largely incomprehensible to the naive listener. We initiated a genome-wide search for linkage in the KE family and have identified a region on chromosome 7 which co-segregates with the speech and language disorder (maximum lod score = 6.62 at theta = 0.0), confirming autosomal dominant inheritance with full penetrance. Further analysis of microsatellites from within the region enabled us to fine map the locus responsible (designated SPCH1) to a 5.6-cM interval in 7q31, thus providing an important step towards its identification. Isolation of SPCH1 may offer the first insight into the molecular genetics of the developmental process that culminates in speech and language.

Abstract

Dent's disease, an X-linked renal tubular disorder, is a form of Fanconi syndrome which is characterized by proteinuria, hypercalciuria, nephrocalcinosis, kidney stones and renal failure. Previous studies localised the gene responsible to Xp11.22, within a microdeletion involving the hypervariable locus DXS255. Further analysis using new probes which flank this locus indicate that the deletion is less than 515 kb. A 185 kb YAC containing DXS255 was used to screen a cDNA library from adult kidney in order to isolate coding sequences falling within the deleted region which may be implicated in the disease aetiology. We identified two clones which are evolutionarily conserved, and detect a 9.5 kb transcript which is expressed predominantly in the kidney. Sequence analysis of 780 bp of ORF from the clones suggests that the identified gene, termed hCIC-K2, encodes a new member of the CIC family of voltage-gated chloride channels. Genomic fragments detected by the cDNA clones are completely absent in patients who have an associated microdeletion. On the basis of the expression pattern, proposed function and deletion mapping, hCIC-K2 is a strong candidate for Dent's disease.

Abstract

The rise of molecular genetics is having a pervasive influence in a wide variety of fields, including research into neurodevelopmental disorders like dyslexia, speech and language impairments, and autism. There are many studies underway which are attempting to determine the roles of genetic factors in the aetiology of these disorders. Beyond the obvious implications for diagnosis, treatment and understanding, success in these efforts promises to shed light on the links between genes and aspects of cognition and behaviour. However, the deceptive simplicity of finding correlations between genetic and phenotypic variation has led to a common misconception that there exist straightforward linear relationships between specific genes and particular behavioural and/or cognitive outputs. The problem is exacerbated by the adoption of an abstract view of the nature of the gene, without consideration of molecular, developmental or ontogenetic frameworks. To illustrate the limitations of this perspective, I select two cases from recent research into the genetic underpinnings of neurodevelopmental disorders. First, I discuss the proposal that dyslexia can be dissected into distinct components specified by different genes. Second, I review the story of the FOXP2 gene and its role in human speech and language. In both cases, adoption of an abstract concept of the gene can lead to erroneous conclusions, which are incompatible with current knowledge of molecular and developmental systems. Genes do not specify behaviours or cognitive processes; they make regulatory factors, signalling molecules, receptors, enzymes, and so on, that interact in highly complex networks, modulated by environmental influences, in order to build and maintain the brain. I propose that it is necessary for us to fully embrace the complexity of biological systems, if we are ever to untangle the webs that link genes to cognition.

Abstract

The human capacity to acquire complex language seems to be without parallel in the natural world. The origins of this remarkable trait have long resisted adequate explanation, but advances in fields that range from molecular genetics to cognitive neuroscience offer new promise. Here we synthesize recent developments in linguistics, psychology and neuroimaging with progress in comparative genomics, gene-expression profiling and studies of developmental disorders. We argue that language should be viewed not as a wholesale innovation, but as a complex reconfiguration of ancestral systems that have been adapted in evolutionarily novel ways.

Abstract

The human Xp11.23-p11.22 interval has been implicated in several inherited diseases including Wiskott-Aldrich syndrome; three forms of X-linked hypercalciuric nephrolithiaisis; and the eye disorders retinitis pigmentosa 2, congenital stationary night blindness, and Aland Island eye disease. In constructing YAC contigs spanning Xp11. 23-p11.22, we have previously shown that the region around the synaptophysin (SYP) gene is refractory to cloning in YACs, but highly stable in cosmids. Preliminary analysis of the latter suggested that this might reflect a high density of coding sequences and we therefore undertook the complete sequencing of a SYP-containing cosmid. Sequence data were extensively analyzed using computer programs such as CENSOR (to mask repeats), BLAST (for homology searches), and GRAIL and GENE-ID (to predict exons). This revealed the presence of 29 putative exons, organized into three genes, in addition to the 7 exons of the complete SYP coding region, all mapping within a 44-kb interval. Two genes are novel, one (CACNA1F) showing high homology to alpha1 subunits of calcium channels, the other (LMO6) encoding a product with significant similarity to LIM-domain proteins. RT-PCR and Northern blot studies confirmed that these loci are indeed transcribed. The third locus is the previously described, but not previously localized, A4 differentiation-dependent gene. Given that the intron-exon boundaries predicted by the analysis are consistent with previous information where available, we have been able to suggest the genomic organization of the novel genes with some confidence. The region has an elevated GC content (>53%), and we identified CpG islands associated with the 5' ends of SYP, A4, and LMO6. The order of loci was Xpter-A4-LMO6-SYP-CACNA1F-Xcen, with intergenic distances ranging from approximately 300 bp to approximately 5 kb. The density of transcribed sequences in this area (>80%) is comparable to that found in the highly gene-rich chromosomal band Xq28. Further studies may aid our understanding of the long-range organization surrounding such gene-enriched regions.

Abstract

The Cha’palaa language of Ecuador (Barbacoan) features verbal morphology for marking knowledge-based categories that, in usage, show a variant of the cross-linguistically recurrent pattern of ‘egophoric distribution': specific forms associate with speakers in contrast to others in statements and with addressees in contrast to others in questions. These are not person markers, but rather are used by speakers to portray their involvement in states of affairs as active, agentive participants (ego) versus other types of involvement (non-ego). They interact with person and argument structure, but through pragmatic ‘person sensitivities’ rather than through grammatical agreement. Not only does this pattern appear in verbal morphology, it also can be observed in alternations of predicate construction types and case alignment, helping to show how egophoric marking is a pervasive element of Cha'palaa's linguistic system. This chapter gives a first account of egophoricity in Cha’palaa, beginning with a discussion of person sensitivity, egophoric distribution, and issues of flexibility of marking with respect to degree of volition or control. It then focuses on a set of intransitive experiencer (or ‘endopathic') predicates that refer to internal states which mark egophoric values for the undergoer role, not the actor role, showing ‘quirky’ accusative marking instead of nominative case. It concludes with a summary of how egophoricity in Cha'palaa interacts with issues of argument structure in comparison to a language with person agreement, here represented by examples from Cha’palaa’s neighbor Ecuadorian Highland Quechua.

Abstract

This paper examines code and style shifting during sales transactions based on two market case studies from highland Ecuador. Bringing together ideas of linguistic economy with work on stylistic variation and ethnohistorical research on Andean markets, I study bartering, market calls and sales pitches to show how sellers create stylistic performances distinguished by contrasts of code, register and poetic features. The interaction of the symbolic value of language with the economic values of the market presents a place to examine the relationship between discourse and the material world.

Abstract

It has long been claimed that there is no lexical field of smell, and that smell is of too little validity to be expressed in grammar. We demonstrate both claims are false. The Cha'palaa language (Ecuador) has at least 15 abstract smell terms, each of which is formed using a type of classifier previously thought not to exist. Moreover, using conversational corpora we show that Cha'palaa speakers also talk about smell more than Imbabura Quechua and English speakers. Together, this shows how language and social interaction may jointly reflect distinct cultural orientations towards sensory experience in general and olfaction in particular.

Abstract

Gratitude is argued to have evolved to motivate and maintain social reciprocity among people, and to be linked to a wide range of positive effects — social, psychological, and even physical. But is socially reciprocal behaviour dependent on the expression of gratitude, for example by saying "thank you" as in English? Current research has not included cross-cultural elements, and has tended to conflate gratitude as an emotion with gratitude as a linguistic practice, as might appear to be the case in English. Here we ask to what extent people actually express gratitude in different societies by focussing on episodes of everyday life where someone obtains a good, service, or support from another, and comparing these episodes across eight languages from five continents. What we find is that expressions of gratitude in these episodes are remarkably rare, suggesting that social reciprocity in everyday life relies on tacit understandings of people’s rights and duties surrounding mutual assistance and collaboration. At the same time, we also find minor cross-cultural variation, with slightly higher rates in Western European languages English and Italian, showing that universal tendencies of social reciprocity should not be conflated with more culturally variable practices of expressing gratitude. Our study complements previous experimental and culture-specific research on social reciprocity with a systematic comparison of audiovisual corpora of naturally occurring social interaction from different cultures from around the world.

Abstract

Patients with stroke offer a unique window into understanding human brain function. Mapping stroke lesions poses several challenges due to the complexity of the lesion anatomy and the mechanisms causing local and remote disruption on brain networks. In this prospective longitudinal study, we compare standard and advanced approaches to white matter lesion mapping applied to acute stroke patients with aphasia. Eighteen patients with acute left hemisphere stroke were recruited and scanned within two weeks from symptom onset. Aphasia assessment was performed at baseline and six-month follow-up. Structural and diffusion MRI contrasts indicated an area of maximum overlap in the anterior external/extreme capsule with diffusion images showing a larger overlap extending into posterior perisylvian regions. Anatomical predictors of recovery included damage to ipsilesional tracts (as shown by both structural and diffusion images) and contralesional tracts (as shown by diffusion images only). These findings indicate converging results from structural and diffusion lesion mapping methods but also clear differences between the two approaches in their ability to identify predictors of recovery outside the lesioned regions.

Abstract

Structural imaging based on computerized tomography (CT) and magnetic resonance imaging (MRI) has progressively replaced traditional post‐mortem studies in the process of identifying the neuroanatomical basis of language. In the clinical setting, the information provided by structural imaging has been used to confirm the exact diagnosis and formulate an individualized treatment plan. In the research arena, neuroimaging has permitted to understand neuroanatomy at the individual and group level. The possibility to obtain quantitative measures of lesions has improved correlation analyses between severity of symptoms, lesion load, and lesion location. More recently, the development of structural imaging based on diffusion MRI has provided valid solutions to two major limitations of more conventional imaging. In stroke patients, diffusion can visualize early changes due to a stroke that are otherwise not detectable with more conventional structural imaging, with important implications for the clinical management of acute stroke patients. Beyond the sensitivity to early changes, diffusion imaging tractography presents the possibility of visualizing the trajectories of individual white matter pathways connecting distant regions. A pathway analysis based on tractography is offering a new perspective in neurolinguistics. First, it permits to formulate new anatomical models of language function in the healthy brain and allows to directly test these models in the human population without any reliance on animal models. Second, by defining the exact location of the damage to specific white matter connections we can understand the contribution of different mechanisms to the emergence of language deficits (e.g., cortical versus disconnection mechanisms). Finally, a better understanding of the anatomical variability of different language networks is helping to identify new anatomical predictors of language recovery. In this chapter we will focus on the principles of structural MRI and, in particular, diffusion imaging and tractography and present examples of how these methods have informed our understanding of variance in language performances in the healthy brain and language deficits in patient populations.

Abstract

The human brain supports acquisition mechanisms that extract structural regularities implicitly from experience without the induction of an explicit model. It has been argued that the capacity to generalize to new input is based on the acquisition of abstract representations, which reflect underlying structural regularities in the input ensemble. In this study, we explored the outcome of this acquisition mechanism, and to this end, we investigated the neural correlates of artificial syntactic classification using event-related functional magnetic resonance imaging. The participants engaged once a day during an 8-day period in a short-term memory acquisition task in which consonant-strings generated from an artificial grammar were presented in a sequential fashion without performance feedback. They performed reliably above chance on the grammaticality classification tasks on days 1 and 8 which correlated with a corticostriatal processing network, including frontal, cingulate, inferior parietal, and middle occipital/occipitotemporal regions as well as the caudate nucleus. Part of the left inferior frontal region (BA 45) was specifically related to syntactic violations and showed no sensitivity to local substring familiarity. In addition, the head of the caudate nucleus correlated positively with syntactic correctness on day 8 but not day 1, suggesting that this region contributes to an increase in cognitive processing fluency.

Abstract

The information we obtain from how speakers sound—for example their accent—affects how we interpret the messages they convey. A clear example is foreign accented speech, where reduced intelligibility and speaker's social categorization (out-group member) affect memory and the credibility of the message (e.g., less trustworthiness). In the present study, we go one step further and ask whether evaluations of messages are also affected by regional accents—accents from a different region than the listener. In the current study, we report results from three experiments on immediate memory recognition and immediate credibility assessments as well as the illusory truth effect. These revealed no differences between messages conveyed in local—from the same region as the participant—and regional accents—from native speakers of a different country than the participants. Our results suggest that when the accent of a speaker has high intelligibility, social categorization by accent does not seem to negatively affect how we treat the speakers' messages.

Abstract

The information we obtain from how speakers sound—for example their accent—affects how we interpret the
messages they convey. A clear example is foreign accented speech, where reduced intelligibility and speaker's
social categorization (out-group member) affect memory and the credibility of the message (e.g., less trust-
worthiness). In the present study, we go one step further and ask whether evaluations of messages are also
affected by regional accents—accents from a different region than the listener. In the current study, we report
results from three experiments on immediate memory recognition and immediate credibility assessments as well
as the illusory truth effect. These revealed no differences between messages conveyed in local—from the same
region as the participant—and regional accents—from native speakers of a different country than the partici-
pants. Our results suggest that when the accent of a speaker has high intelligibility, social categorization by
accent does not seem to negatively affect how we treat the speakers' messages.

Abstract

The aim of the present fMRI study was to investigate whether typical and dyslexic adult readers differed in the neural correlates of audiovisual speech processing. We tested for Blood Oxygen-Level Dependent (BOLD) activity differences between these two groups in a 1-back task, as they processed written (word, illegal consonant strings) and spoken (auditory, visual and audiovisual) stimuli. When processing written stimuli, dyslexic readers showed reduced activity in the supramarginal gyrus, a region suggested to play an important role in phonological processing, but only when they processed strings of consonants, not when they read words. During the speech perception tasks, dyslexic readers were only slower than typical readers in their behavioral responses in the visual speech condition. Additionally, dyslexic readers presented reduced neural activation in the auditory, the visual, and the audiovisual speech conditions. The groups also differed in terms of superadditivity, with dyslexic readers showing decreased neural activation in the regions of interest. An additional analysis focusing on vision-related processing during the audiovisual condition showed diminished activation for the dyslexic readers in a fusiform gyrus cluster. Our results thus suggest that there are differences in audiovisual speech processing between dyslexic and normal readers. These differences might be explained by difficulties in processing the unisensory components of audiovisual speech, more specifically, dyslexic readers may benefit less from visual information during audiovisual speech processing than typical readers. Given that visual speech processing supports the development of phonological skills fundamental in reading, differences in processing of visual speech could contribute to differences in reading ability between typical and dyslexic readers.

Abstract

Results from a recent neuroimaging study on spoken sentence comprehension have been interpreted as evidence for cortical entrainment to hierarchical syntactic structure. We present a simple computational model that predicts the power spectra from this study, even
though the model's linguistic knowledge is restricted to the lexical level, and word-level representations are not combined into higher-level units (phrases or sentences). Hence, the
cortical entrainment results can also be explained from the lexical properties of the stimuli, without recourse to hierarchical syntax.

Abstract

Speaking and listening are complex tasks that we perform on a daily basis, almost without conscious effort. Interestingly, speaking almost never occurs without listening: whenever we speak, we at least hear our own speech. The research in this thesis is concerned with how the perception of our own speech influences our speaking behavior. We show that unconsciously, we actively monitor this auditory feedback of our own speech. This way, we can efficiently take action and adapt articulation when an error occurs and auditory feedback does not correspond to our expectation. Processing the auditory feedback of our speech does not, however, automatically affect speech production. It is subject to a number of constraints. For example, we do not just track auditory feedback, but also its consistency. If auditory feedback is more consistent over time, it has a stronger influence on speech production. In addition, we investigated how auditory feedback during speech is processed in the brain, using magnetoencephalography (MEG). The results suggest the involvement of a broad cortical network including both auditory and motor-related regions. This is consistent with the view that the auditory center of the brain is involved in comparing auditory feedback to our expectation of auditory feedback. If this comparison yields a mismatch, motor-related regions of the brain can be recruited to alter the ongoing articulations.

Abstract

When talking, speakers continuously monitor and use the auditory feedback of their own voice to control and inform speech production processes. When speakers are provided with auditory feedback that is perturbed in real time, most of them compensate for this by opposing the feedback perturbation. But some speakers follow the perturbation. In the current study, we investigated whether the state of the speech production system at perturbation onset may determine what type of response (opposing or following) is given. The results suggest that whether a perturbation-related response is opposing or following depends on ongoing fluctuations of the production system: It initially responds by doing the opposite of what it was doing. This effect and the non-trivial proportion of following responses suggest that current production models are inadequate: They need to account for why responses to unexpected sensory feedback depend on the production-system’s state at the time of perturbation.

Abstract

Speaking is a complex motor skill which requires near instantaneous integration of sensory and motor-related information. Current theory hypothesizes a complex interplay between motor and auditory processes during speech production, involving the online comparison of the speech output with an internally generated forward model. To examine the neural correlates of this intricate interplay between sensory and motor processes, the current study uses altered auditory feedback (AAF) in combination with magnetoencephalography (MEG). Participants vocalized the vowel/e/and heard auditory feedback that was temporarily pitch-shifted by only 25 cents, while neural activity was recorded with MEG. As a control condition, participants also heard the recordings of the same auditory feedback that they heard in the first half of the experiment, now without vocalizing. The participants were not aware of any perturbation of the auditory feedback. We found auditory cortical areas responded more strongly to the pitch shifts during vocalization. In addition, auditory feedback perturbation resulted in spectral power increases in the θ and lower β bands, predominantly in sensorimotor areas. These results are in line with current models of speech production, suggesting auditory cortical areas are involved in an active comparison between a forward model's prediction and the actual sensory input. Subsequently, these areas interact with motor areas to generate a motor response. Furthermore, the results suggest that θ and β power increases support auditory-motor interaction, motor error detection and/or sensory prediction processing.