Publications

Abstract

We used eye-tracking to investigate if and when children show an incremental bias to assume that the first noun phrase in a sentence is the agent (first-NP-as-agent bias) while processing the meaning of English active and passive transitive sentences. We also investigated whether children can override this bias to successfully distinguish active from passive sentences, after processing the remainder of the sentence frame. For this second question we used eye-tracking (Study 1) and forced-choice pointing (Study 2). For both studies, we used a paradigm in which participants simultaneously saw two novel actions with reversed agent-patient relations while listening to active and passive sentences. We compared English-speaking 25-month-olds and 41-month-olds in between-subjects sentence structure conditions (Active Transitive Condition vs. Passive Condition). A permutation analysis found that both age groups showed a bias to incrementally map the first noun in a sentence onto an agent role. Regarding the second question, 25-month-olds showed some evidence of distinguishing the two structures in the eye-tracking study. However, the 25-month-olds did not distinguish active from passive sentences in the forced choice pointing task. In contrast, the 41-month-old children did reanalyse their initial first-NP-as-agent bias to the extent that they clearly distinguished between active and passive sentences both in the eye-tracking data and in the pointing task. The results are discussed in relation to the development of syntactic (re)parsing.

Abstract

Conformist transmission, defined as a disproportionate likelihood to copy the majority, is considered a potent mechanism underlying the emergence and stabilization of cultural diversity. However, ambiguity within and across disciplines remains as to how to identify conformist transmission empirically. In most studies, a population level outcome has been taken as the benchmark to evidence conformist transmission: a sigmoidal relation between individuals’ probability to copy the majority and the proportional majority size. Using an individual-based model, we show that, under ecologically plausible conditions, this sigmoidal relation can also be detected without equipping individuals with a conformist bias. Situations in which individuals copy randomly from a fixed subset of demonstrators in the population, or in which they have a preference for one of the possible variants, yield similar sigmoidal patterns as a conformist bias would. Our findings warrant a revisiting of studies that base their conformist transmission conclusions solely on the sigmoidal curve. More generally, our results indicate that population level outcomes interpreted as conformist transmission could potentially be explained by other individual-level strategies, and that more empirical support is needed to prove the existence of an individual-level conformist bias in human and other animals.

Abstract

Self-monitoring in production is critical to correct performance, and recent accounts suggest that such monitoring may occur via the detection of response conflict. The error-related negativity (ERN) is a response-locked event-related potential (ERP) that is sensitive to response conflict. The present study examines whether response conflict is detected in production by exploring a situation where multiple outputs are activated: the bilingual naming of form-related equivalents (i.e. cognates). ERPs were recorded while German-Dutch bilinguals named pictures in their first and second languages. Although cognates were named faster than non-cognates, response conflict was evident in the form of a larger ERN-like response for cognates and adaptation effects on naming, as the magnitude of cognate facilitation was smaller following the naming of cognates. Given that signals of response conflict are present during correct naming, the present results suggest that such conflict may serve as a reliable signal for monitoring in speech production.

Abstract

Schinzel-Giedion syndrome (SGS) is a rare developmental disorder characterized by multiple malformations, severe neurological alterations and increased risk of malignancy. SGS is caused by de novo germline mutations clustering to a 12bp hotspot in exon 4 of SETBP1. Mutations in this hotspot disrupt a degron, a signal for the regulation of protein degradation, and lead to the accumulation of SETBP1 protein. Overlapping SETBP1 hotspot mutations have been observed recurrently as somatic events in leukemia. We collected clinical information of 47 SGS patients (including 26 novel cases) with germline SETBP1 mutations and of four individuals with a milder phenotype caused by de novo germline mutations adjacent to the SETBP1 hotspot. Different mutations within and around the SETBP1 hotspot have varying effects on SETBP1 stability and protein levels in vitro and in in silico modeling. Substitutions in SETBP1 residue I871 result in a weak increase in protein levels and mutations affecting this residue are significantly more frequent in SGS than in leukemia. On the other hand, substitutions in residue D868 lead to the largest increase in protein levels. Individuals with germline mutations affecting D868 have enhanced cell proliferation in vitro and higher incidence of cancer compared to patients with other germline SETBP1 mutations. Our findings substantiate that, despite their overlap, somatic SETBP1 mutations driving malignancy are more disruptive to the degron than germline SETBP1 mutations causing SGS. Additionally, this suggests that the functional threshold for the development of cancer driven by the disruption of the SETBP1 degron is higher than for the alteration in prenatal development in SGS. Drawing on previous studies of somatic SETBP1 mutations in leukemia, our results reveal a genotype-phenotype correlation in germline SETBP1 mutations spanning a molecular, cellular and clinical phenotype.

Abstract

Intracranial volume reflects the maximally attained brain size during development, and remains stable with loss of tissue in late
life. It is highly heritable, but the underlying genes remain largely undetermined. In a genome-wide association study of 32,438
adults, we discovered five previously unknown loci for intracranial volume and confirmed two known signals. Four of the loci were
also associated with adult human stature, but these remained associated with intracranial volume after adjusting for height.
We found a high genetic correlation with child head circumference (genetic = 0.748), which indicates a similar genetic
background and allowed us to identify four additional loci through meta-analysis (Ncombined = 37,345). Variants for intracranial
volume were also related to childhood and adult cognitive function, and Parkinson’s disease, and were enriched near genes
involved in growth pathways, including PI3K-AKT signaling. These findings identify the biological underpinnings of intracranial
volume and provide genetic support for theories on brain reserve and brain overgrowth.

Abstract

A repetition-suppression functional magnetic resonance imaging paradigm was used to explore the neuroanatomical substrates of processing two types of acoustic variation—speaker and accent—during spoken sentence comprehension. Recordings were made for two speakers and two accents: Standard Dutch and a novel accent of Dutch. Each speaker produced sentences in both accents. Participants listened to two sentences presented in quick succession while their haemodynamic responses were recorded in an MR scanner. The first sentence was spoken in Standard Dutch; the second was spoken by the same or a different speaker and produced in Standard Dutch or in the artificial accent. This design made it possible to identify neural responses to a switch in speaker and accent independently. A switch in accent was associated with activations in predominantly left-lateralized areas including posterior temporal regions, including superior temporal gyrus, planum temporale (PT), and supramarginal gyrus, as well as in frontal regions, including left pars opercularis of the inferior frontal gyrus (IFG). A switch in speaker recruited a predominantly right-lateralized network, including middle frontal gyrus and prenuneus. It is concluded that posterior temporal areas, including PT, and frontal areas, including IFG, are involved in processing accent variation in spoken sentence comprehension

Abstract

We investigated how two distortions of the speech signal–added background noise and speech in an unfamiliar accent - affect comprehension of speech using functional Magnetic Resonance Imaging (fMRI). Listeners performed a speeded sentence verification task for speech in quiet in Standard Dutch, in Standard Dutch with added background noise, and for speech in an unfamiliar accent of Dutch. The behavioural results showed slower responses for both types of distortion compared to clear speech, and no difference between the two distortions. The neuroimaging results showed that, compared to clear speech, processing noise resulted in more activity bilaterally in Inferior Frontal Gyrus, Frontal Operculum, while processing accented speech recruited an area in left Superior Temporal Gyrus/Sulcus. It is concluded that the neural bases for processing different distortions of the speech signal dissociate. It is suggested that current models of the cortical organisation of speech are updated to specifically associate bilateral inferior frontal areas with processing external distortions (e.g., background noise) and left temporal areas with speaker-related distortions (e.g., accents).

Abstract

Oppositional defiant disorder (ODD) is a frequent psychiatric disorder seen in children and adolescents with attention-deficit-hyperactivity disorder (ADHD). ODD is also a common antecedent to both affective disorders and aggressive behaviors. Although the heritability of ODD has been estimated to be around 0.60, there has been little research into the molecular genetics of ODD. The present study examined the association of irritable and defiant/vindictive dimensions and categorical subtypes of ODD (based on latent class analyses) with previously described specific polymorphisms (DRD4 exon3 VNTR, 5-HTTLPR, and seven OXTR SNPs) as well as with dopamine, serotonin, and oxytocin genes and pathways in a clinical sample of children and adolescents with ADHD. In addition, we performed a multivariate genome-wide association study (GWAS) of the aforementioned ODD dimensions and subtypes. Apart from adjusting the analyses for age and sex, we controlled for "parental ability to cope with disruptive behavior." None of the hypothesis-driven analyses revealed a significant association with ODD dimensions and subtypes. Inadequate parenting behavior was significantly associated with all ODD dimensions and subtypes, most strongly with defiant/vindictive behaviors. In addition, the GWAS did not result in genome-wide significant findings but bioinformatics and literature analyses revealed that the proteins encoded by 28 of the 53 top-ranked genes functionally interact in a molecular landscape centered around Beta-catenin signaling and involved in the regulation of neurite outgrowth. Our findings provide new insights into the molecular basis of ODD and inform future genetic studies of oppositional behavior. (c) 2015 The Authors. American Journal of Medical Genetics Part B: Neuropsychiatric Genetics Published by Wiley Periodicals, Inc.

Abstract

Ischemic stroke causes transient increase of neural stem and progenitor cell (NSPC) proliferation in the subventricular zone (SVZ), and migration of newly formed neuroblasts toward the damaged area where they mature to striatal neurons. The molecular mechanisms regulating this plastic response, probably involved in structural reorganization and functional recovery, are poorly understood. The adaptor protein LNK suppresses hematopoietic stem cell self-renewal, but its presence and role in the brain are poorly understood. Here we demonstrate that LNK is expressed in NSPCs in the adult mouse and human SVZ. Lnk−/− mice exhibited increased NSPC proliferation after stroke, but not in intact brain or following status epilepticus. Deletion of Lnk caused increased NSPC proliferation while overexpression decreased mitotic activity of these cells in vitro. We found that Lnk expression after stroke increased in SVZ through the transcription factors STAT1/3. LNK attenuated insulin-like growth factor 1 signaling by inhibition of AKT phosphorylation, resulting in reduced NSPC proliferation. Our findings identify LNK as a stroke-specific, endogenous negative regulator of NSPC proliferation, and suggest that LNK signaling is a novel mechanism influencing plastic responses in postischemic brain.

Abstract

Across many languages from unrelated families, spoken-word recognition is subject to a constraint whereby potential word candidates must contain a vowel. This constraint minimizes competition from embedded words (e.g., in English, disfavoring win in twin because t cannot be a word). However, the constraint would be counter-productive in certain languages that allow stand-alone vowelless open-class words. One such language is Berber (where t is indeed a word). Berber listeners here detected words affixed to nonsense contexts with or without vowels. Length effects seen in other languages replicated in Berber, but in contrast to prior findings, word detection was not hindered by vowelless contexts. When words can be vowelless, otherwise universal constraints disfavoring vowelless words do not feature in spoken-word recognition.

Abstract

The recent trend away from ANOVA-based analyses places experimental investigations into the neurobiology of cognition in more naturalistic and ecologically valid designs within reach. Using mixed-effects models for epoch-based regression, we demonstrate the feasibility of examining event-related potentials (ERPs), and in particular the N400, to study the neural dynamics of human auditory language processing in a naturalistic setting. Despite the large variability between trials during naturalistic stimulation, we replicated previous findings from the literature: the effects of frequency, animacy, word order and find previously unexplored interaction effects. This suggests a new perspective on ERPs, namely as a continuous modulation reflecting continuous stimulation instead of a series of discrete and essentially sequential processes locked to discrete events.

Significance Statement Laboratory experiments on language often lack ecologicalal validity. In addition to the intrusive laboratory equipment, the language used is often highly constrained in an attempt to control possible confounds. More recent research with naturalistic stimuli has been largely confined to fMRI, where the low temporal resolution helps to smooth over the uneven finer structure of natural language use. Here, we demonstrate the feasibility of using naturalistic stimuli with temporally sensitive methods such as EEG and MEG using modern computational approaches and show how this provides new insights into the nature of ERP components and the temporal dynamics of language as a sensory and cognitive process. The full complexity of naturalistic language use cannot be captured by carefully controlled designs alone.

Abstract

Language evolution can be viewed from two viewpoints: the development of a communicative system and the biological adaptations necessary for producing and perceiving said system. The communicative-system vantage point has enjoyed a wealth of mathematical models based on simple distributional properties of language, often formulated as empirical laws. However, be- yond vague psychological notions of “least effort”, no principled explanation has been proposed for the existence and success of such laws. Meanwhile, psychological and neurobiological mod- els have focused largely on the computational constraints presented by incremental, real-time processing. In the following, we show that information-theoretic entropy underpins successful models of both types and provides a more principled motivation for Zipf’s Law

Abstract

Experiments in Artificial Language Learn-
ing have revealed much about the cogni-
tive mechanisms underlying sequence and
language learning in human adults, in in-
fants and in non-human animals. This pa-
per focuses on their ability to generalize
to novel grammatical instances (i.e., in-
stances consistent with a familiarization
pattern). Notably, the propensity to gen-
eralize appears to be negatively correlated
with the amount of exposure to the artifi-
cial language, a fact that has been claimed
to be contrary to the predictions of statis-
tical models (Pe
̃
na et al. (2002); Endress
and Bonatti (2007)). In this paper, we pro-
pose to model generalization as a three-
step process, and we demonstrate that the
use of statistical models for the first two
steps, contrary to widespread intuitions in
the ALL-field, can explain the observed
decrease of the propensity to generalize
with exposure time.

Abstract

We present the Retention and Recognition model (R&R), a probabilistic exemplar model that accounts for segmentation in Artificial Language Learning experiments. We show that R&R provides an excellent fit to human responses in three segmentation experiments with adults (Frank et al., 2010), outperforming existing models. Additionally, we analyze the results of the simulations and propose alternative explanations for the experimental findings.

Abstract

In an influential paper, Marcus et al. [1999] claimed that connectionist models
cannot account for human success at learning tasks that involved generalization
of abstract knowledge such as grammatical rules. This claim triggered a heated
debate, centered mostly around variants of the Simple Recurrent Network model
[Elman, 1990]. In our work, we revisit this unresolved debate and analyze the
underlying issues from a different perspective. We argue that, in order to simulate
human-like learning of grammatical rules, a neural network model should not be
used as a
tabula rasa
, but rather, the initial wiring of the neural connections and
the experience acquired prior to the actual task should be incorporated into the
model. We present two methods that aim to provide such initial state: a manipu-
lation of the initial connections of the network in a cognitively plausible manner
(concretely, by implementing a “delay-line” memory), and a pre-training algorithm
that incrementally challenges the network with novel stimuli. We implement such
techniques in an Echo State Network [Jaeger, 2001], and we show that only when
combining both techniques the ESN is able to learn truly general identity rules.

Abstract

The present paper assesses discourse-pragmatic factors as a potential explanation for the subject-object assymetry in early child language. It identifies a set of factors which characterize typical situations of informativeness (Greenfield & Smith, 1976), and uses these factors to identify informative arguments in data from four children aged 2;0 through 3;6 learning Inuktitut as a first language. In addition, it assesses the extent of the links between features of informativeness on one hand and lexical vs. null and subject vs. object arguments on the other. Results suggest that a pragmatics account of the subject-object asymmetry can be upheld to a greater extent than previous research indicates, and that several of the factors characterizing informativeness are good indicators of those arguments which tend to be omitted in early child language.

Abstract

To explain the phenomenon that certain English verbs resist passivization (e.g., *£5 was cost by the book), Pinker (1989) proposed a semantic constraint on the passive in the adult grammar: The greater the extent to which a verb denotes an action where a patient is affected or acted upon, the greater the extent to which it is compatible with the passive. However, a number of comprehension and production priming studies have cast doubt upon this claim, finding no difference between highly affecting agent-patient/theme-experiencer passives (e.g., Wendy was kicked/frightened by Bob) and non-actional experiencer theme passives (e.g., Wendy was heard by Bob). The present study provides evidence that a semantic constraint is psychologically real, and is readily observed when more fine-grained independent and dependent measures are used (i.e., participant ratings of verb semantics, graded grammaticality judgments, and reaction time in a forced-choice picture-matching comprehension task). We conclude that a semantic constraint on the passive must be incorporated into accounts of the adult grammar.

Abstract

The present study investigated how children learn that some verbs may appear in the figure-locative but not the ground-locative construction (e.g., Lisa poured water into the cup; *Lisa poured the cup with water), with some showing the opposite pattern (e.g., *Bart filled water into the cup; Bart filled the cup with water), and others appearing in both (Lisa sprayed water onto the flowers; Lisa sprayed the flowers with water). Grammatical acceptability judgments were obtained for the use of each of 142 locative verbs (60 for children) in each sentence type. Overall, and for each age group individually, the judgment data were best explained by a model that included ratings of the extent to which each verb exhibits both the broad- and narrow-range semantic properties of the figure- and ground-locative constructions (relating mainly to manner and end-state respectively; Pinker, 1989) and the statistical-learning measure of overall verb frequency (entrenchment; Braine & Brooks, 1995). A second statistical-learning measure, frequency in each of the two locative constructions (pre-emption; Goldberg, 1995), was found to have no additional dissociable effect. We conclude by drawing together various theoretical proposals to arrive at a possible account of how semantics and statistics interact in the retreat from overgeneralization.

Abstract

Children (aged five-to-six and nine-to-ten years) and adults rated the acceptability of well-formed sentences and argument-structure overgeneralization errors involving the prepositional-object and double-object dative constructions (e.g. Marge pulled the box to Homer/*Marge pulled Homer the box). In support of the entrenchment hypothesis, a negative correlation was observed between verb frequency and the acceptability of errors, across all age groups. Adults additionally displayed sensitivity to narrow-range semantic constraints on the alternation, rejecting double-object dative uses of novel verbs consistent with prepositional-dative-only classes and vice versa. Adults also provided evidence for the psychological validity of a proposed morphophonological constraint prohibiting Latinate verbs from appearing in the double-object dative. These findings are interpreted in the light of a recent account of argument-structure acquisition, under which children retreat from error by incrementally learning the semantic, phonological, and pragmatic properties associated with particular verbs and particular construction slots.*

Abstract

his work offers a modern description of Ewe(GBE), a Kwa (Niger-Congo) language of West Africa. It assumes that the “essence of linguistics is the quest for meaning” (Whorf) and investigates the meanings of grammatical constructions and illocutionary devices representing them in Natural Semantic Metalanguage (NSM) style explications. The explications account for the range of use of the constructions suggested by data from diversified mediated discourse: television and radio interviews and drama, written plays and fiction as well as insider knowledge of and observed behaviour both as participant and observer in Ewe communities of practice. The author draws ecumenically on insights from functional and formal linguistic approaches. The work opens with an overview of Ewe structural grammar. The rest of the work is divided into three parts. Part II concentrates on property denoting expressions, imperfective aspect constructions and possession. Part III examines the grammatical resources available to the Ewe speaker for packaging information in a clause: scene-setting constructions, a “capability passive” construction and experiential constructions. In Part IV illocutionary devices such as formulaic and routine expressions, address terms and interjections are described paying attention to their socio-cultural dimensions of use. This work is of interest to Africanists and linguists interested in grammatical description, typology, semantics and pragmatics as well as anthropologists interested in ethnography of communication and the relation between language and culture.

Abstract

Particles are little words that speakers use to signal the illocutionary force of utterances and/or express their attitude towards elements of the communicative situation, e.g. the addresses. This paper presents an overview of the classification, meaning and use of utterance particles in Ewe. It argues that they constitute a grammatical word class on functional and distributional grounds. The paper calls for a cross-cultural investigation of particles, especially in Africa, where they have been neglected for far too long.

Abstract

This paper explores the role of various types of location control in descriptions of placement events in Hungarian. It will be shown that general verb choices cannot be explained in terms of spatial relations (such as containment and support) or spatial relational changes (such as joining and separation). On the contrary, all main verb distinctions within the placement domain can be described in terms of agentive control settings between the Figure and agentive entities (e.g., the Agent, other persons). In Hungarian, only events with continuous agentive control along the motion trajectory are described as either ‘putting’ or ‘taking’, and only events where the Figure is furthermore controlled by a non-agentive entity at the Goal are described as ‘putting’.

Abstract

The present behavioral study aimed to examine the impact of language control expertise on two domain-general control processes, i.e. active inhibition of competing representations and overcoming of inhibition. We compared how Simultaneous Interpreters (SI) and Highly Proficient Bilinguals—two groups assumed to differ in language control capacity—performed executive tasks involving specific inhibition processes. In Experiment 1 (language decision task), both active and overcoming of inhibition processes are involved, while in Experiment 2 (bilingual Stroop task) only interference suppression is supposed to be required. The results of Experiment 1 showed a language switching effect only for the highly proficient bilinguals, potentially because overcoming of inhibition requires more cognitive resources than in SI. Nevertheless, both groups performed similarly on the Stroop task in Experiment 2, which suggests that active inhibition may work similarly in both groups. These contrasting results suggest that overcoming of inhibition may be harder to master than active inhibition. Taken together, these data indicate that some executive control processes may be less sensitive to the degree of expertise in bilingual language control than others. Our findings lend support to psycholinguistic models of bilingualism postulating a higher-order mechanism regulating language activation.

Abstract

In this study, event related potentials (ERPs) were used to investigate the extent to which dyslexics (aged 9–13 years) differ from normally reading controls in early ERPs, which reflect prelexical orthographic processing, and in late ERPs, which reflect implicit phonological processing. The participants performed an implicit reading task, which was manipulated in terms of letter-specific processing, orthographic familiarity, and phonological structure. Comparing consonant- and symbol sequences, the results showed significant differences in the P1 and N1 waveforms in the control but not in the dyslexic group. The reduced P1 and N1 effects in pre-adolescent children with dyslexia suggest a lack of visual specialization for letter-processing. The P1 and N1 components were not sensitive to the familiar vs. less familiar orthographic sequence contrast. The amplitude of the later N320 component was larger for phonologically legal (pseudowords) compared to illegal (consonant sequences) items in both controls and dyslexics. However, the topographic differences showed that the controls were more left-lateralized than the dyslexics. We suggest that the development of the mechanisms that support literacy skills in dyslexics is both delayed and follows a non-normal developmental path. This contributes to the hemispheric differences observed and might reflect a compensatory mechanism in dyslexics.

Abstract

Naming speed deficits are well documented in developmental dyslexia, expressed by slower naming times and more errors in response to familiar items. Here we used event-related potentials (ERPs) to examine at what processing level the deficits in dyslexia emerge during a discrete-naming task. Dyslexic and skilled adult control readers performed a primed object-naming task, in which the relationship between the prime and the target was manipulated along perceptual, semantic and phonological dimensions. A 3×2 design that crossed Relationship Type (Visual, Phonemic Onset, and Semantic) with Relatedness (Related and Unrelated) was used. An attenuated N/P190 – indexing early visual processing – and N300 – which index late visual processing – was observed to pictures preceded by perceptually related (vs. unrelated) primes in the control but not in the dyslexic group. These findings suggest suboptimal processing in early stages of object processing in dyslexia, when integration and mapping of perceptual information to a more form-specific percept in memory take place. On the other hand, both groups showed an N400 effect associated with semantically related pictures (vs. unrelated), taken to reflect intact integration of semantic similarities in both dyslexic and control readers. We also found an electrophysiological effect of phonological priming in the N400 range – that is, an attenuated N400 to objects preceded by phonemic related primes vs. unrelated – while it showed a more widespread distributed and more pronounced over the right hemisphere in the dyslexics. Topographic differences between groups might have originated from a word form encoding process with different characteristics in dyslexics compared to control readers.

Abstract

The RELISH project promotes language-oriented research by addressing a two-pronged problem: (1) the lack of harmonization between digital standards for lexical information in Europe and America, and (2) the lack of interoperability among existing lexicons of endangered languages, in particular those created with the Shoebox/Toolbox lexicon building software. The cooperation partners in the RELISH project are the University of Frankfurt (FRA), the Max Planck Institute for Psycholinguistics (MPI Nijmegen), and Eastern Michigan University, the host of the Linguist List (ILIT). The project aims at harmonizing key European and American digital standards whose divergence has hitherto impeded international collaboration on language technology for resource creation and analysis, as well as web services for archive access. Focusing on several lexicons of endangered languages, the project will establish a unified way of referencing lexicon structure and linguistic concepts, and develop a procedure for migrating these heterogeneous lexicons to a standards-compliant format. Once developed, the procedure will be generalizable to the large store of lexical resources involved in the LEGO and DoBeS projects.

Abstract

Cognitive neuroscientists of language comprehension study how neural computations relate to cognitive computations during comprehension. On the cognitive part of the equation, it is important that the computations and processing complexity are explicitly defined. Probabilistic language models can be used to give a computationally explicit account of language complexity during comprehension. Whereas such models have so far predominantly been evaluated against behavioral data, only recently have the models been used to explain neurobiological signals. Measures obtained from these models emphasize the probabilistic, information-processing view of language understanding and provide a set of tools that can be used for testing neural hypotheses about language comprehension. Here, we provide a cursory review of the theoretical foundations and example neuroimaging studies employing probabilistic language models. We highlight the advantages and potential pitfalls of this approach and indicate avenues for future research

Abstract

Do individuals differ in how efficiently they process non-native sounds? To what extent do these differences relate to individual variability in sound-learning aptitude? We addressed these questions by assessing the sound-learning abilities of Dutch native speakers as they were trained on non-native tone contrasts. We used fMRI repetition suppression to the non-native tones to measure participants' neuronal processing efficiency before and after training. Although all participants improved in tone identification with training, there was large individual variability in learning performance. A repetition suppression effect to tone was found in the bilateral inferior frontal gyri (IFGs) before training. No whole-brain effect was found after training; a region-of-interest analysis, however, showed that, after training, repetition suppression to tone in the left IFG correlated positively with learning. That is, individuals who were better in learning the non-native tones showed larger repetition suppression in this area. Crucially, this was true even before training. These findings add to existing evidence that the left IFG plays an important role in sound learning and indicate that individual differences in learning aptitude stem from differences in the neuronal efficiency with which non-native sounds are processed.

Abstract

Background: Altered levels of urocortin 1 (Ucn1) in the centrally projecting Edinger-Westphal nucleus (EWcp) of depressed suicide attempters or completers mediate the brain’s response to stress, while the mechanism regulating Ucn1 expression is unknown. We tested the hypothesis that microRNAs (miRNAs), which are vital fine-tuners of gene expression during the brain’s response to stress, have the capacity to modulate Ucn1 expression. Methods: Computational analysis revealed that the Ucn1 3’ untranslated region contained a conserved binding site for miR-326. We examined miR-326 and Ucn1 levels in the EWcp of depressed suicide completers. In addition, we evaluated miR-326 and Ucn1 levels in the serum and the EWcp of a chronic variable mild stress (CVMS) rat model of behavioural despair and after recovery from CVMS, respectively. Gain and loss of miR-326 function experiments examined the regulation of Ucn1 by this miRNA in cultured midbrain neurons. Results: We found reduced miR-326 levels concomitant with elevated Ucn1 levels in the EWcp of depressed suicide completers as well as in the EWcp of CVMS rats. In CVMS rats fully recovered from stress, both serum and EWcp miR-326 levels rebounded to nonstressed levels. While downregulation of miR-326 levels in primary midbrain neurons enhanced Ucn1 expression levels, miR-326 overexpression selectively reduced the levels of this neuropeptide. Limitations: This study lacked experiments showing that in vivo alteration of miR-326 levels alleviate depression-like behaviours. We show only correlative data for miR-325 and cocaine- and amphetamine-regulated transcript levels in the EWcp. Conclusion: We identified miR-326 dysregulation in depressed suicide completers and characterized this miRNA as an upstream regulator of the Ucn1 neuropeptide expression in midbrain neurons. © 2016 Joule Inc. or its licensors.

Abstract

The use of subject pronouns by bilingual speakers using both a pro-drop and a non-pro-drop language (e.g. Spanish heritage speakers in the USA) is a well-studied topic in research on cross-linguistic influence in language contact situations. Previous studies looking at bilinguals with different proficiency levels have yielded conflicting results on whether there is transfer from the non-pro-drop patterns to the pro-drop language. Additionally, previous research has focused on speech patterns only. In this paper, we study the two modalities of language, speech and gesture, and ask whether and how they reveal cross-linguistic influence on the use of subject pronouns in discourse. We focus on elicited narratives from heritage speakers of Turkish in the Netherlands, in both Turkish (pro-drop) and Dutch (non-pro-drop), as well as from monolingual control groups. The use of pronouns was not very common in monolingual Turkish narratives and was constrained by the pragmatic contexts, unlike in Dutch. Furthermore, Turkish pronouns were more likely to be accompanied by localized gestures than Dutch pronouns, presumably because pronouns in Turkish are pragmatically marked forms. We did not find any cross-linguistic influence in bilingual speech or gesture patterns, in line with studies (speech only) of highly proficient bilinguals. We therefore suggest that speech and gesture parallel each other not only in monolingual but also in bilingual production. Highly proficient heritage speakers who have been exposed to diverse linguistic and gestural patterns of each language from early on maintain monolingual patterns of pragmatic constraints on the use of pronouns multimodally.

Abstract

Speakers use differential referring expressions in pragmatically appropriate ways to produce coherent narratives. Languages, however, differ in a) whether REs as arguments can be dropped and b) whether personal pronouns encode gender. We examine two languages that differ from each other in these two aspects and ask whether the co-reference context and the gender encoding options affect the use of REs differentially. We elicited narratives from Dutch and Turkish speakers about two types of three-person events, one including people of the same and the other of mixed-gender. Speakers re-introduced referents into the discourse with fuller forms (NPs) and maintained them with reduced forms (overt or null pronoun). Turkish speakers used pronouns mainly to mark emphasis and only Dutch speakers used pronouns differentially across the two types of videos. We argue that linguistic possibilities available in languages tune speakers into taking different principles into account to produce pragmatically coherent narratives

Abstract

Integration of separate memories forms the basis of inferential reasoning - an essential cognitive process that enables complex behavior. Considerable evidence suggests that both hippocampus and medial prefrontal cortex (mPFC) play a crucial role in memory integration. Although previous studies indicate that theta oscillations facilitate memory processes, the electrophysiological mechanisms underlying memory integration remain elusive. To bridge this gap, we recorded magnetoencephalography data while participants performed an inference task and employed novel source reconstruction techniques to estimate oscillatory signals from the hippocampus. We found that hippocampal theta power during encoding predicts subsequent memory integration. Moreover, we observed increased theta coherence between hippocampus and mPFC. Our results suggest that integrated memory representations arise through hippocampal theta oscillations, possibly reflecting dynamic switching between encoding and retrieval states, and facilitating communication with mPFC. These findings have important implications for our understanding of memory-based decision making and knowledge acquisition

Abstract

Understanding a word in context relies on a cascade of perceptual and conceptual processes, starting with modality-specific input decoding, and leading to the unification of the word's meaning into a discourse model. One critical cognitive event, turning a sensory stimulus into a meaningful linguistic sign, is the access of a semantic representation from memory. Little is known about the changes that activating a word's meaning brings about in cortical dynamics. We recorded the electroencephalogram (EEG) while participants read sentences that could contain a contextually unexpected word, such as ‘cold’ in ‘In July it is very cold outside’. We reconstructed trajectories in phase space from single-trial EEG time series, and we applied three nonlinear measures of predictability and complexity to each side of the semantic access boundary, estimated as the onset time of the N400 effect evoked by critical words. Relative to controls, unexpected words were associated with larger prediction errors preceding the onset of the N400. Accessing the meaning of such words produced a phase transition to lower entropy states, in which cortical processing becomes more predictable and more regular. Our study sheds new light on the dynamics of information flow through interfaces between sensory and memory systems during language processing.

Abstract

This chapter provides a partial overview of some currently debated issues in the cognitive science of language. We distinguish two families of problems, which we refer to as ‘language and cognition’ and ‘linguistics and cognition’. Under the first heading we present and discuss the hypothesis that language, in particular the semantics of tense and aspect, is grounded in the planning system. We emphasize the role of non-monotonic inference during language comprehension. We look at the converse issue of the role of linguistic interpretation in reasoning tasks. Under the second heading we investigate the two foremost assumptions of current linguistic methodology, namely intuitions as the only adequate empirical basis of theories of meaning and grammar and the competence-performance distinction, arguing that these are among the heaviest burdens for a truly comprehensive approach to language. Marr’s three-level scheme is proposed as an alternative methodological framework, which we apply in a review of two ERP studies on semantic processing, to the ‘binding problem’ for language, and in a conclusive set of remarks on relating theories in the cognitive science of language.

Abstract

The way the brain binds together words to form sentences may depend on whether and how the arising cognitive representation is to be used in behavior. The amplitude of the N400 effect in event-related brain potentials is inversely correlated with the degree of fit of a word's meaning into a semantic representation of the preceding discourse. This study reports a double dissociation in the latency characteristics of the N400 effect depending on task demands. When participants silently read words in a sentence context, without issuing a relevant overt response, greater temporal alignment over recording sites occurs for N400 onsets than peaks. If however a behavior is produced – here pressing a button in a binary probe selection task – exactly the opposite pattern is observed, with stronger alignment of N400 peaks than onsets. The peak amplitude of the N400 effect correlates best with the latency characteristic showing less temporal dispersion. These findings suggest that meaning construction in the brain is subtly affected by task demands, and that there is complex functional integration between semantic combinatorics and control systems handling behavioral goals.

Abstract

Autism is characterized by impairments in reciprocal social interaction and communication, and restricted and sterotyped patterns of interests and activities. Developmental difficulties are apparent before 3 years of age and there is evidence for strong genetic influences most likely involving more than one susceptibility gene. A two-stage genome search for susceptibility loci in autism was performed on 87 affected sib pairs plus 12 non-sib affected relative-pairs, from a total of 99 families identified by an international consortium. Regions on six chromosomes (4, 7, 10, 16, 19 and 22) were identified which generated a multipoint maximum lod score (MLS) > 1. A region on chromosome 7q was the most significant with an MLS of 3.55 near markers D7S530 and D7S684 in the subset of 56 UK affected sib-pair families, and an MLS of 2.53 in all 87 affected sib-pair families. An area on chromosome 16p near the telomere was the next most significant, with an MLS of 1.97 in the UK families, and 1.51 in all families. These results are an important step towards identifying genes predisposing to autism; establishing their general applicability requires further study.

Abstract

We examined 33 participants of a one-week Scottish Gaelic course and compared them to 34 controls: 16 active controls who participated in courses of comparable duration and intensity but not involving foreign language learning and 18 passive controls who followed their usual routines. Participants completed auditory tests of attentional inhibition and switching. There was no difference between the groups in any measures at the beginning of the course. At the end of the course, a significant improvement in attention switching was observed in the language group (p < .001) but not the control group (p = .127), independent of the age of participants (18–78 years). Half of the language participants (n = 17) were retested nine months after their course. All those who practiced Gaelic 5 hours or more per week improved from their baseline performance. In contrast, those who practiced 4 hours or fewer showed an inconsistent pattern: some improved while others stayed the same or deteriorated. Our results suggest that even a short period of intensive language learning can modulate attentional functions and that all age groups can benefit from this effect. Moreover, these short-term effects can be maintained through continuous practice.

Abstract

Reasons play an important role in social interaction. We study reasons-giving in the context of request sequences in Russian. By contrasting request sequences with and without reasons, we are able to shed light on the interactional work people do when they provide reasons or ask for them. In a systematic collection of request sequences in everyday conversation (N = 158), we find reasons in a variety of sequential positions, showing the various points at which participants may orient to the need for a reason. Reasons may be left implicit (as in many minimal requests that are readily complied with), or they can be made explicit. Participants may make reasons explicit either as part of the initial formulation of a request or in an interactionally contingent way. Across sequential positions, we show that reasons for requests recurrently deal with three possible issues: (1) providing information when a request is underspecified, (2) managing relationships between the requester and requestee and (3) explicating ancillary actions implemented by a request. By spelling out information normally left to presuppositions and implicatures, reasons make requests more understandable and help participants to navigate the social landscape of asking assistance from others.

Abstract

In many languages modal auxiliaries such as English can, must, may, need, will, ought, want are ambiguous between two types of interpretations: epistemic and root interpretations. In the epistemic interpretation the modal expresses how likely it is that a proposition is true (for example, necessarily, possibly, probably true) while in the root interpretations the modal expresses the obligatoriness, permissibility, desirability, or possibility of a state or event. A central question in much syntactic research on modal auxiliaries has been whether this systematic semantic ambiguity corresponds to a syntactic distinction. A commonly accepted answer has been that in epistemic interpretations the modal verb is a monadic predicate while in root interpretations it is a dyadic predicate, typically a relation between a subject and an infinitival verb. This distinction between monadic and dyadic modal predicates has been modeled syntactically in various ways: (i) in terms of lexical argument structure, that is, as the distinction between raising and control verbs; (ii) in terms of different base positions in the array of functional heads making up the clausal spine, with epistemic modals being higher than root modals; (iii) in terms of a higher syntactic position for epistemically interpreted modals after raising at the level of semantic interpretation (LF raising); (iv) in terms of the nature of the complement of the modal. This chapter evaluates these proposals, drawing on data from, among others, English, Dutch, Icelandic, German, and Catalan and taking into account cross-linguistic differences in the modal systems. One important conclusion is that the alleged correspondence between the epistemic/root distinction and the raising/control distinction is too simple, as there are sentences with root interpretations but a raising syntax. The chapter ends with a list of questions for future research.

Abstract

Measurement bias is defined as a violation of measurement invariance, which can be investigated through multigroup factor analysis (MGFA), by testing across-group differences in intercepts (uniform bias) and factor loadings (nonuniform bias). Restricted factor analysis (RFA) can also be used to detect measurement bias. To also enable nonuniform bias detection, we extend RFA with latent moderated structures (LMS) or use a random slope parameterization (RSP). In a simulation study we compare the MGFA, RFA/LMS, and RFA/RSP methods in detecting measurement bias, varying type of bias (uniform, nonuniform), type of the variable that violates measurement invariance (dichotomous, continuous), and its relationship with the trait that we want to measure (independent, dependent). For each condition, 500 sets of data are generated and analyzed with each of the three detection methods, in single run and in an iterative procedure. The RFA methods outperform MGFA when the violating variable is continuous.

Abstract

Maximum likelihood factor analysis of discrete data within the structural equation modeling framework rests on the assumption that the observed discrete responses are manifestations of underlying continuous scores that are normally distributed. As maximizing the likelihood of multivariate response patterns is computationally very intensive, the sum of the log–likelihoods of the bivariate response patterns is maximized instead. Little is yet known about how to assess model fit when the analysis is based on such a pairwise maximum likelihood (PML) of two–way contingency tables. We propose new fit criteria for the PML method and conduct a simulation study to evaluate their performance in model selection. With large sample sizes (500 or more), PML performs as well the robust weighted least squares analysis of polychoric correlations.

Abstract

Recent social-cognitive research suggests that the anticipation of co-actors' actions influences people's mental representations. However, the precise nature of such representations is still unclear. In this study we investigated verbal joint representations in a delayed Stroop paradigm, where each participant responded to one color after a short delay. Participants either performed the task as a single actor (single-action, Experiment 1), or they performed it together (joint-action, Experiment 2). We investigated effects of co-actors' actions on the ERP components associated with perceptual conflict (Go N2) and response selection (P3b). Compared to single-action, joint-action reduced the N2 amplitude congruency effect when participants had to respond (Go trials), indicating that representing a co-actor's utterance helped to dissociate action codes and attenuated perceptual conflict for the responding participant. Yet, on NoGo trials the centro-parietal P3 (P3b) component amplitude increased for joint-action, suggesting that participants mapped the stimuli onto the co-actor's upcoming response as if it were their own response. We conclude that people represent others' utterances similarly to the way they represent their own utterances, and that shared perception-action codes for self and others can sometimes reduce, rather than enhance, perceptual conflict.

Abstract

In conversation, turn-taking is usually fluid, with next speakers taking their turn right after the end of the previous turn. Most, but not all, previous studies show that next speakers start to plan their turn early, if possible already during the incoming turn. The present study makes use of the list-completion paradigm (Barthel et al., 2016), analyzing speech onset latencies and eye-movements of participants in a task-oriented dialogue with a confederate. The measures are used to disentangle the contributions to the timing of turn-taking of early planning of content on the one hand and initiation of articulation as a reaction to the upcoming turn-end on the other hand. Participants named objects visible on their computer screen in response to utterances that did, or did not, contain lexical and prosodic cues to the end of the incoming turn. In the presence of an early lexical cue, participants showed earlier gaze shifts toward the target objects and responded faster than in its absence, whereas the presence of a late intonational cue only led to faster response times and did not affect the timing of participants' eye movements. The results show that with a combination of eye-movement and turn-transition time measures it is possible to tease apart the effects of early planning and response initiation on turn timing. They are consistent with models of turn-taking that assume that next speakers (a) start planning their response as soon as the incoming turn's message can be understood and (b) monitor the incoming turn for cues to turn-completion so as to initiate their response when turn-transition becomes relevant

Abstract

In conversation, interlocutors rarely leave long gaps between turns, suggesting that next speak- ers begin to plan their turns while listening to the previous speaker. The present experiment used analyses of speech onset latencies and eye-movements in a task-oriented dialogue paradigm to investigate when speakers start planning their response. Adult German participants heard a confederate describe sets of objects in utterances that either ended in a noun (e.g. Ich habe eine Tür und ein Fahrrad (‘I have a door and a bicycle’)) or a verb form (Ich habe eine Tür und ein Fahrrad besorgt (‘I have gotten a door and a bicycle’)), while the presence or absence of the final verb either was or was not predictable from the preceding sentence structure. In response, participants had to name any unnamed objects they could see in their own display in utterances such as Ich habe ein Ei (‘I have an egg’). The main question was when participants started to plan their response. The results are consistent with the view that speakers begin to plan their turn as soon as sufficient information is available to do so, irrespective of further incoming words.

Abstract

Oscillatory neuronal activity may provide a mechanism for dynamic network coordination. Rhythmic neuronal interactions can be quantified using multiple metrics, each with their own advantages and disadvantages. This tutorial will review and summarize current analysis methods used in the field of invasive and non-invasive electrophysiology to study the dynamic connections between neuronal populations. First, we review metrics for functional connectivity, including coherence, phase synchronization, phase-slope index, and Granger causality, with the specific aim to provide an intuition for how these metrics work, as well as their quantitative definition. Next, we highlight a number of interpretational caveats and common pitfalls that can arise when performing functional connectivity analysis, including the common reference problem, the signal to noise ratio problem, the volume conduction problem, the common input problem, and the sample size bias problem. These pitfalls will be illustrated by presenting a set of MATLAB-scripts, which can be executed by the reader to simulate each of these potential problems. We discuss how these issues can be addressed using current methods.

Abstract

Analysis of the functions of nominal apposition in a number of Latin authors representing different periods, genres, and
linguistic registers shows (1) that nominal apposition in Latin had a wide variety of functions; (2) that genre had some
effect on functional use; (3) that change did not affect semantic fields as such; and (4) that with time the occurrence of
apposition increasingly came to depend on the semantic field and within the semantic field on the individual lexical items.
The ‘per-word’ treatment –also attested for the structural development of nominal apposition– underscores the specific
characteristics of nominal apposition as a phenomenon at the cross-roads of syntax and derivational morphology

Abstract

Nominal apposition—the combining of two equivalent nouns—has been a neglected topic in (Indo-European) linguistics, despite its prominence in syntax and morphology (i.c. composition). This book presents an extensive comparative and diachronic analysis of nominal apposition in Indo-European, examining its occurrence, its syntactic and morphological characteristics and functions in the early languages, identifying parallels with similar phenomena elsewhere (e.g. noun classification and script determinatives), and tracing its evolution in Latin-Romance.
While nominal apposition is not exclusive to Indo-European, its development fits the evolution of Indo-European grammar.

Abstract

Background: There is variability in the language of children with autism, even those who are high functioning. However, little is known about how they process language structures in real time, including how they handle potential ambiguity, and whether they follow referential constraints. Previous research with older autism spectrum disorder (ASD) participants has shown that these individuals can use context to access rapidly the meaning of ambiguous words. The severity of autism has also been shown to influence the speed in which children with ASD access lexical information. Aims: To understand more about how children with ASD process language in real time (i.e., as it unfolds). The focus was the integration of information and use of referential constraints to identify a referent named in a sentence. Methods & Procedures: We used an eye-tracking task to compare performance between young, high-functioning children with autism (HFA) and children with typical development (TD). A large sample of 5–9-year-old children (mean age = 6;8 years), 48 with HFA and 56 with TD participated; all were attending mainstream schools. For each item participants were shown a display of four images that differed in two dimensions. Each sentence contained an adjective and noun that restricted the choice from four to two (the target and competitor), followed by a prepositional phrase (e.g., the blue square with dots); this added modifying information to provide a unique description of the target. We calculated looking time at the target, the competitor and the two distractors for each 200 ms time interval as children processed the sentence and looked at the display. Generalized estimating equations were used to carry out repeated-measures analyses on the proportion of looking time to target and competitor and time to fixate to target. Outcomes & Results: Children in both groups (HFA and TD) looked at the target and competitor more than at the distractors following the adjective and noun and following the modifying information in the prepositional phrase more at the target. However, the HFA group was significantly slower in both phases and looked proportionally less at the target. Across the sample, IQ and language did not affect the results; however, age and attention had an impact. The older children showed an advantage in processing the information as did the children with higher attention scores. Conclusions & Implications: The HFA group took longer than the TD group to integrate the disambiguating information provided in the course of processing a sentence and integrate it with the visual information, indicating that for the ASD group incremental processing was not as advanced as for children with ASD, and they were less sensitive to referential conventions. Training for young children with ASD on the use of referential conventions and available contextual clues may be of benefit to them in understanding the language they hear.

Abstract

Research with adults and older children indicates that verb biases are strong influences on listeners’ interpretations when processing sentences, but they can be overruled. In this paper, we ask two questions: (i) are children with Autism Spectrum Disorder (ASD) who are high functioning sensitive to verb biases like their same age typically developing peers?, and (ii) do young children with ASD and young children with typical development (TD) override strong verb biases to consider alternative interpretations of ambiguous sentences? Participants were aged 5–9 years (mean age 6.65 years): children with ASD who were high functioning and children with TD. In task 1, biasing and neutral verbs were included (e.g., eat cake versus move cake). In task 2, the focus was on whether the prepositional phrase occurring with an instrument biasing verb (e.g., ‘Chop the tree with the axe’) was interpreted as an instrument even if the named item was an implausible instrument (e.g., candle in ‘Cut the cake with the candle’). Overall, the results showed similarities between groups but the ASD group was generally slower. In task 1, both groups looked at the named object faster in the biasing than the non-biasing condition, and in the biasing condition the ASD group looked away from the target more quickly than the TD group. In task 2, both groups identified the target in the prepositional phrase. They were more likely to override the verb instrument bias and consider the alternative (modification) interpretation in the implausible condition (e.g., looking at the picture of a cake with a candle on it’). Our findings indicate that children of age 5 years and above can use context to override verb biases. Additionally, an important component of the sentence processing mechanism is largely intact for young children with ASD who are high functioning. Like children with TD, they draw on verb semantics and plausibility in integrating information. However, they are likely to be slower in processing the language they hear. Based on previous findings of associations between processing speed and cognitive functioning, the implication is that their understanding will be negatively affected, as will their academic outcomes.

Abstract

Genome-wide association screens aim to identify common genetic variants contributing to the phenotypic variability of complex traits, such as human height or brain morphology. The identified genetic variants are mostly within noncoding genomic regions and the biology of the genotype–phenotype association typically remains unclear. In this article, we propose a complementary targeted strategy to reveal the genetic underpinnings of variability in subcortical brain volumes, by specifically selecting genomic loci that are experimentally validated forebrain enhancers, active in early embryonic development. We hypothesized that genetic variation within these enhancers may affect the development and ultimately the structure of subcortical brain regions in adults. We tested whether variants in forebrain enhancer regions showed an overall enrichment of association with volumetric variation in subcortical structures of >13,000 healthy adults. We observed significant enrichment of genomic loci that affect the volume of the hippocampus within forebrain enhancers (empirical P = 0.0015), a finding which robustly passed the adjusted threshold for testing of multiple brain phenotypes (cutoff of P < 0.0083 at an alpha of 0.05). In analyses of individual single nucleotide polymorphisms (SNPs), we identified an association upstream of the ID2 gene with rs7588305 and variation in hippocampal volume. This SNP-based association survived multiple-testing correction for the number of SNPs analyzed but not for the number of subcortical structures. Targeting known regulatory regions offers a way to understand the underlying biology that connects genotypes to phenotypes, particularly in the context of neuroimaging genetics. This biology-driven approach generates testable hypotheses regarding the functional biology of identified associations.

Abstract

This study explored whether infants aged 12 months already recognize the communicative function of pointing gestures. Infants participated in a task requiring them to comprehend an adult’s informative pointing gesture to the location of a hidden toy. They mostly succeeded in this task, which required them to infer that the adult was attempting to direct their attention to a location for a reason – because she wanted them to know that a toy was hidden there. Many of the infants also reversed roles and produced appropriate pointing gestures for the adult in this same game, and indeed there was a correlation such that comprehenders were for the most part producers. These findings indicate that by 12 months of age infants are beginning to show a bidirectional understanding of communicative pointing.

Abstract

In the blocked-cyclic naming paradigm, participants repeatedly name small sets of objects that do or do not belong to the same semantic category. A standard finding is that, after a first presentation cycle where one might find semantic facilitation, naming is slower in related (homogeneous) than in unrelated (heterogeneous) sets. According to competitive theories of lexical selection, this is because the lexical representations of the object names compete more vigorously in homogeneous than in heterogeneous sets. However, Navarrete, del Prato, Peressotti, and Mahon (2014) argued that this pattern of results was not due to increased lexical competition but to weaker repetition priming in homogeneous compared to heterogeneous sets. They demonstrated that when homogeneous sets were not repeated immediately but interleaved with unrelated sets, semantic relatedness induced facilitation rather than interference. We replicate this finding but also show that the facilitation effect has a strategic origin: It is substantial when sets are separated by pauses, making it easy for participants to notice the relatedness within some sets and use it to predict upcoming items. However, the effect is much reduced when these pauses are eliminated. In our view, the semantic facilitation effect does not constitute evidence against competitive theories of lexical selection. It can be accounted for within any framework that acknowledges strategic influences on the speed of object naming in the blocked-cyclic naming paradigm.

Abstract

In an investigation of contextual influences on sound categorization, 64 Peruvian Spanish listeners categorized vowels on an /i/ to /e/ continuum. First, to measure the influence of the stimulus range (broad acoustic context) and the preceding stimuli (local acoustic context), listeners were presented with different subsets of the Spanish /i/-/e/ continuum in separate blocks. Second, the influence of the number of response categories was measured by presenting half of the participants with /i/ and /e/ as responses, and the other half with /i/, /e/, /a/, /o/, and /u/. The results showed that the perceptual category boundary between /i/ and /e/ shifted depending on the stimulus range and that the formant values of locally preceding items had a contrastive influence. Categorization was less susceptible to broad and local acoustic context effects, however, when listeners were presented with five rather than two response options. Vowel categorization depends not only on the acoustic properties of the target stimulus, but also on its broad and local acoustic context. The influence of such context is in turn affected by the number of internal referents that are available to the listener in a task.

Abstract

The study of first language acquisition still strongly relies on behavioural methods to measure underlying linguistic abilities. In the present paper, we closely examine and model one such method, the headturn preference procedure (HPP), which is widely used to measure infant speech segmentation and word recognition abilities Our model takes real speech as input, and only uses basic sensory processing and cognitive capabilities to simulate observable behaviour.We show that the familiarity effect found in many HPP experiments can be simulated without using the phonetic and phonological skills necessary for segmenting test sentences into words. The explicit modelling of the process that converts the result of the cognitive processing of the test sentences into observable behaviour uncovered two issues that can lead to null-results in HPP studies. Our simulations show that caution is needed in making inferences about underlying language skills from behaviour in HPP experiments. The simulations also generated questions that must be addressed in future HPP studies.

Abstract

nfants start learning words, the building blocks of language, at least by 6 months. To do so, they must be able to extract the phonological form of words from running speech. A rich literature has investigated this process, termed word segmentation. We addressed the fundamental question of how infants of different ages segment words from their native language using a meta-analytic approach. Based on previous popular theoretical and experimental work, we expected infants to display familiarity preferences early on, with a switch to novelty preferences as infants become more proficient at processing and segmenting native speech. We also considered the possibility that this switch may occur at different points in time as a function of infants' native language and took into account the impact of various task- and stimulus-related factors that might affect difficulty. The combined results from 168 experiments reporting on data gathered from 3774 infants revealed a persistent familiarity preference across all ages. There was no significant effect of additional factors, including native language and experiment design. Further analyses revealed no sign of selective data collection or reporting. We conclude that models of infant information processing that are frequently cited in this domain may not, in fact, apply in the case of segmenting words from native speech.

Abstract

How does a naive language learner deal with speaker variation irrelevant to distinguishing word meanings? Experimental data is contradictory, and incompatible models have been proposed. Here, we examine basic assumptions regarding the acoustic signal the learner deals with: Is speaker variability a hurdle in discriminating sounds or can it easily be ignored? To this end, we summarize existing infant data. We then present machine-based discriminability scores of sound pairs obtained without any language knowledge. Our results show that speaker variability decreases sound contrast discriminability, and that some contrasts are affected more than others. However, chance performance is rare; most contrasts remain discriminable in the face of speaker variation. We take our results to mean that speaker variation is not a uniform hurdle to discriminating sound contrasts, and careful examination is necessary when planning and interpreting studies testing whether and to what extent infants (and adults) are sensitive to speaker differences.

Abstract

Pronouns seem to be acquired in an asymmetrical way, where children confuse the meaning of pronouns with reflexives up to the age of six, but not vice versa. Children’s production of the same referential expressions is appropriate at the age of four. However, response-based tasks, the usual means to investigate child language comprehension, are very demanding given children’s limited cognitive resources. Therefore, they might affect performance. To assess the impact of the task, we investigated learners of Dutch (three- and four-year-olds) using both eye-tracking, a non-demanding on-line method, and a typical response-based task. Eye-tracking results show an emerging ability to correctly comprehend pronouns at the age of four. A response-based task fails to indicate this ability across age groups, replicating results of earlier studies. Additionally, biases seem to influence the outcome of the response-based task. These results add new evidence to the ongoing debate of the asymmetrical acquisition of pronouns and reflexives and suggest that there is less of an asymmetry than previously assumed.

Abstract

Recent work has made available a number of standardized meta- analyses bearing on various aspects of infant language processing. We utilize data from two such meta-analyses (discrimination of vowel contrasts and word segmentation, i.e., recognition of word forms extracted from running speech) to assess whether the published body of empirical evidence supports a bottom-up versus a top-down theory of early phonological development by leveling the power of results from thousands of infants. We predicted that if infants can rely purely on auditory experience to develop their phonological categories, then vowel discrimination and word segmentation should develop in parallel, with the latter being potentially lagged compared to the former. However, if infants crucially rely on word form information to build their phonological categories, then development at the word level must precede the acquisition of native sound categories. Our results do not support the latter prediction. We discuss potential implications and limitations, most saliently that word forms are only one top-down level proposed to affect phonological development, with other proposals suggesting that top-down pressures emerge from lexical (i.e., word-meaning pairs) development. This investigation also highlights general procedures by which standardized meta-analyses may be reused to answer theoretical questions spanning across phenomena.

Abstract

In this chapter, the multilingual systems of bilingual speakers of Sursilvan Romansh and German are analyzed. The Romansh and the German systems show important differences in the domain of placement. Romansh has a fairly general verb metter ‘to put’ whereas German uses different verbs (e.g., setzen ‘to set’, legen ‘to lay’, stellen ‘to stand’). Whereas there are almost no traces of German in the Romansh data elicited from the German-Romansh bilinguals, it appears that their production of German yields uses of the verbs which differ from the typical German system. Although the forms of the German verbs have been acquired by the bilingual speakers, their distribution in the data arguably reflects traces of the Romansh category of metter ‘to put’.

Abstract

Following right-hemisphere damage, a specific disorder of motor awareness can occur called anosognosia for hemiplegia, i.e. the denial of motor deficits contralateral to a brain lesion. The study of anosognosia can offer unique insights into the neurocognitive basis of awareness. Typically, however, awareness is assessed as a first person judgement and the ability of patients to think about their bodies in more ‘objective’ (third person) terms is not directly assessed. This may be important as right-hemisphere spatial abilities may underlie our ability to take third person perspectives. This possibility was assessed for the first time in the present study. We investigated third person perspective taking using both visuospatial and verbal tasks in right-hemisphere stroke patients with anosognosia ( n = 15) and without anosognosia ( n = 15), as well as neurologically healthy control subjects ( n = 15). The anosognosic group performed worse than both control groups when having to perform the tasks from a third versus a first person perspective. Individual analysis further revealed a classical dissociation between most anosognosic patients and control subjects in mental (but not visuospatial) third person perspective taking abilities. Finally, the severity of unawareness in anosognosia patients was correlated to greater impairments in such third person, mental perspective taking abilities (but not visuospatial perspective taking). In voxel-based lesion mapping we also identified the lesion sites linked with such deficits, including some brain areas previously associated with inhibition, perspective taking and mentalizing, such as the inferior and middle frontal gyri, as well as the supramarginal and superior temporal gyri. These results suggest that neurocognitive deficits in mental perspective taking may contribute to anosognosia and provide novel insights regarding the relation between self-awareness and social cognition.

Abstract

Crossmodal binding usually relies on bottom-up stimulus characteristics such as spatial and temporal correspondence. However, in case of ambiguity the brain has to decide whether to combine or segregate sensory inputs. We hypothesise that widespread, subtle forms of synesthesia provide crossmodal mapping patterns which underlie and influence multisensory perception. Our aim was to investigate if such a mechanism plays a role in the case of pitch-size stimulus combinations. Using a combination of psychophysics and ERPs, we could show that despite violations of spatial correspondence, the brain specifically integrates certain stimulus combinations which are congruent with respect to our hypothesis of pitch-size synesthesia, thereby impairing performance on an auditory spatial localisation task (Ventriloquist effect). Subsequently, we perturbed this process by functionally disrupting a brain area known for its role in multisensory processes, the right intraparietal sulcus, and observed how the Ventriloquist effect was abolished, thereby increasing behavioural performance. Correlating behavioural, TMS and ERP results, we could retrace the origin of the synesthestic pitch-size mappings to a right intraparietal involvement around 250 ms. The results of this combined psychophysics, TMS and ERP study provide evidence for shifting the current viewpoint on synesthesia more towards synesthesia being at the extremity of a spectrum of normal, adaptive perceptual processes, entailing close interplay between the different sensory systems. Our results support this spectrum view of synesthesia by demonstrating that its neural basis crucially depends on normal multisensory processes. (C) 2011 Elsevier Inc. All rights reserved.

Abstract

The Chapacuran language family, with three extant members and nine historically attested lects, has yet to be classified following modern standards in historical linguistics. This paper presents an internal classification of these languages by combining both the traditional comparative method (CM) and Bayesian phylogenetic inference (BPI). We identify multiple systematic sound correspondences and 285 cognate sets of basic vocabulary using the available documentation. These allow us to reconstruct a large portion of the Proto-Chapacuran phonemic inventory and identify tentative major subgroupings. The cognate sets form the input for the BPI analysis, which uses a stochastic Continuous-Time Markov Chain to model the change of these cognate sets over time. We test various models of lexical substitution and evolutionary clocks, and use ethnohistorical information and data collection dates to calibrate the resulting trees. The CM and BPI analyses produce largely congruent results, suggesting a division of the family into three different clades.

Abstract

Theories of language acquisition and perceptual learning increasingly rely on statistical learning mechanisms. The current meta-analysis aims to clarify the robustness of this capacity in infancy within the word segmentation literature. Our analysis reveals a significant, small effect size for conceptual replications of Saffran, Aslin, & Newport (1996), and a nonsignificant effect across all studies that incorporate transitional probabilities to segment words. In both conceptual replications and the broader literature, however, statistical learning is moderated by whether stimuli are naturally produced or synthesized. These findings invite deeper questions about the complex factors that influence statistical learning, and the role of statistical learning in language acquisition.

Abstract

Many studies have used test batteries for the evaluation of affective behavior in rodents. This has the advantage that treatment effects can be examined on different aspects of the affective domain. However, the behavior in one test may affect the behavior in following test. The present study examined possible order effects in rats that were tested in three different tests: Open Field (OF), Zero Maze (ZM) and Forced Swim Test (FST). The data of the present study indicated that the behavior in ZM was the least affected by the order of testing. In contrast, the behavior in the FST (and to a less extend the OF) was dependent on the order of the test in the test battery. Repeated testing in the same test did not change the behavior in the ZM. However, the behavior in the OF and FST changed with repeated testing. The present study indicates that the performance of rats in a test can be dependent on the order in a test battery. Consequently, these data caution the interpretation of treatment effects in studies in which test batteries are used. (C) 2011 Elsevier B.V. All rights reserved.

Abstract

Just as interlocutors can manipulate physical objects for performing certain types of social action, they can also perform different social actions by manipulating symbolic objects. A kinship system can be thought of as an abstract collection of lexical mappings and associated cultural conventions. It is a sort of cognitive object that can be readily manipulated for special purposes. For example, the relationship between pairs of individuals can be momentarily re-construed in constructing jokes or teases. Murriny Patha speakers associate certain parts of the body with particular classes of kin. When a group of Murriny Patha women witness a cultural outsider performing a forearm-holding gesture that is characteristically associated with brothers-in-law, they re-associate the gesture to the husband–wife relationship, thus setting up an extended teasing episode. Many of these teases call on gestural resources. Although the teasing is at times repetitive, and the episode is only thinly populated with the telltale “off-record” markers that characterize teasing proposals as non-serious, the proposal is sufficiently far-fetched as to ensure that the teases come off as more bonding than biting.

Abstract

We examined the contents of language-mediated prediction in toddlers by investigating the extent to which toddlers are sensitive to visual-shape representations of upcoming words. Previous studies with adults suggest limits to the degree to which information about the visual form of a referent is predicted during language comprehension in low constraint sentences. 30-month-old toddlers heard either contextually constraining sentences or contextually neutral sentences as they viewed images that were either identical or shape related to the heard target label. We observed that toddlers activate shape information of upcoming linguistic input in contextually constraining semantic contexts: Hearing a sentence context that was predictive of the target word activated perceptual information that subsequently influenced visual attention toward shape-related targets. Our findings suggest that visual shape is central to predictive language processing in toddlers.

Abstract

Oxytocin is a neuropeptide known to influence how humans share material resources. Here we explore whether oxytocin influences how we share knowledge. We focus on two distinguishing features of human communication, namely the ability to select communicative signals that disambiguate the many-to-many mappings that exist between a signal’s form and meaning, and adjustments of those signals to the presumed cognitive characteristics of the addressee (“audience design”). Fifty-five males participated in a randomized, double-blind, placebo controlled experiment involving the intranasal administration of oxytocin. The participants produced novel non-verbal communicative signals towards two different addressees, an adult or a child, in an experimentally-controlled live interactive setting. We found that oxytocin administration drives participants to generate signals of higher referential quality, i.e. signals that disambiguate more communicative problems; and to rapidly adjust those communicative signals to what the addressee understands. The combined effects of oxytocin on referential quality and audience design fit with the notion that oxytocin administration leads participants to explore more pervasively behaviors that can convey their intention, and diverse models of the addressees. These findings suggest that, besides affecting prosocial drive and salience of social cues, oxytocin influences how we share knowledge by promoting cognitive exploration

Abstract

PROCEEDINGS OF THE 16TH WORLD CONGRESS OF PSYCHOPHYSIOLOGY of the International Organization of Psychophysiology (IOP) Pisa, Italy September 13-17, 2012

Abstract

This paper reviews the prospects for the cross-fertilization of conversation-analytic (CA) and neurocognitive studies of conversation, focusing on turn-taking. Although conversation is the primary ecological niche for language use, relatively little brain research has focused on interactive language use, partly due to the challenges of using brain-imaging methods that are controlled enough to perform sound experiments, but still reflect the rich and spontaneous nature of conversation. Recently, though, brain researchers have started to investigate conversational phenomena, for example by using 'overhearer' or controlled interaction paradigms. We review neuroimaging studies related to turn-taking and sequence organization, phenomena historically described by CA. These studies for example show early action recognition and immediate planning of responses midway during an incoming turn. The review discusses studies with an eye to a fruitful interchange between CA and neuroimaging research on conversation and an indication of how these disciplines can benefit from each other.

Abstract

The perception of temporal contrasts in speech is known to be influenced by the speech rate in the surrounding context. This rate-dependent perception is suggested to involve general auditory processes since it is also elicited by non-speech contexts, such as pure tone sequences. Two general auditory mechanisms have been proposed to underlie rate-dependent perception: durational contrast and neural entrainment. The present study compares the predictions of these two accounts of rate-dependent speech perception by means of four experiments in which participants heard tone sequences followed by Dutch target words ambiguous between /ɑs/ “ash” and /a:s/ “bait”. Tone sequences varied in the duration of tones (short vs. long) and in the presentation rate of the tones (fast vs. slow). Results show that the duration of preceding tones did not influence target perception in any of the experiments, thus challenging durational contrast as explanatory mechanism behind rate-dependent perception. Instead, the presentation rate consistently elicited a category boundary shift, with faster presentation rates inducing more /a:s/ responses, but only if the tone sequence was isochronous. Therefore, this study proposes an alternative, neurobiologically plausible, account of rate-dependent perception involving neural entrainment of endogenous oscillations to the rate of a rhythmic stimulus.

Abstract

In natural situations, speech perception often takes place during the concurrent execution of other cognitive tasks, such as listening while viewing a visual scene. The execution of a dual task typically has detrimental effects on concurrent speech perception, but how exactly cognitive load disrupts speech encoding is still unclear. The detrimental effect on speech representations may consist of either a general reduction in the robustness of processing of the speech signal (‘noisy encoding’), or, alternatively it may specifically influence the temporal sampling of the sensory input, with listeners missing temporal pulses, thus underestimating segmental durations (‘shrinking of time’). The present study investigated whether and how spectral and temporal cues in a precursor sentence that has been processed under high vs. low cognitive load influence the perception of a subsequent target word. If cognitive load effects are implemented through ‘noisy encoding’, increasing cognitive load during the precursor should attenuate the encoding of both its temporal and spectral cues, and hence reduce the contextual effect that these cues can have on subsequent target sound perception. However, if cognitive load effects are expressed as ‘shrinking of time’, context effects should not be modulated by load, but a main effect would be expected on the perceived duration of the speech signal. Results from two experiments indicate that increasing cognitive load (manipulated through a secondary visual search task) did not modulate temporal (Experiment 1) or spectral context effects (Experiment 2). However, a consistent main effect of cognitive load was found: increasing cognitive load during the precursor induced a perceptual increase in its perceived speech rate, biasing the perception of a following target word towards longer durations. This finding suggests that cognitive load effects in speech perception are implemented via ‘shrinking of time’, in line with a temporal sampling framework. In addition, we argue that our results align with a model in which early (spectral and temporal) normalization is unaffected by attention but later adjustments may be attention-dependent.

Abstract

Brain oscillations have been shown to track the slow amplitude fluctuations in speech during comprehension. Moreover, there is evidence that these stimulus-induced cortical rhythms may persist even after the driving stimulus has ceased. However, how exactly this neural entrainment shapes speech perception remains debated. This behavioral study investigated whether and how the frequency and phase of an entrained rhythm would influence the temporal sampling of subsequent speech. In two behavioral experiments, participants were presented with slow and fast isochronous tone sequences, followed by Dutch target words ambiguous between as /ɑs/ “ash” (with a short vowel) and aas /a:s/ “bait” (with a long vowel). Target words were presented at various phases of the entrained rhythm. Both experiments revealed effects of the frequency of the tone sequence on target word perception: fast sequences biased listeners to more long /a:s/ responses. However, no evidence for phase effects could be discerned. These findings show that an entrained rhythm’s frequency, but not phase, influences the temporal sampling of subsequent speech. These outcomes are compatible with theories suggesting that sensory timing is evaluated relative to entrained frequency. Furthermore, they suggest that phase tracking of (syllabic) rhythms by theta oscillations plays a limited role in speech parsing.

Abstract

Anecdotal evidence suggests that unfamiliar languages sound faster than one’s native language. Empirical evidence for this impression has, so far, come from explicit rate judgments. The aim of the present study was to test whether such perceived rate differences between native and foreign languages have effects on implicit speech processing. Our measure of implicit rate perception was “normalization for speaking rate”: an ambiguous vowel between short /a/ and long /a:/ is interpreted as /a:/ following a fast but as /a/ following a slow carrier sentence. That is, listeners did not judge speech rate itself; instead, they categorized ambiguous vowels whose perception was implicitly affected by the rate of the context. We asked whether a bias towards long /a:/ might be observed when the context is not actually faster but simply spoken in a foreign language. A fully symmetrical experimental design was used: Dutch and German participants listened to rate matched (fast and slow) sentences in both languages spoken by the same bilingual speaker. Sentences were followed by nonwords that contained vowels from an /a-a:/ duration continuum. Results from Experiments 1 and 2 showed a consistent effect of rate normalization for both listener groups. Moreover, for German listeners, across the two experiments, foreign sentences triggered more /a:/ responses than (rate matched) native sentences, suggesting that foreign sentences were indeed perceived as faster. Moreover, this Foreign Language effect was modulated by participants’ ability to understand the foreign language: those participants that scored higher on a foreign language translation task showed less of a Foreign Language effect. However, opposite effects were found for the Dutch listeners. For them, their native rather than the foreign language induced more /a:/ responses. Nevertheless, this reversed effect could be reduced when additional spectral properties of the context were controlled for. Experiment 3, using explicit rate judgments, replicated the effect for German but not Dutch listeners. We therefore conclude that the subjective impression that foreign languages sound fast may have an effect on implicit speech processing, with implications for how language learners perceive spoken segments in a foreign language.

Abstract

In conversation, our own speech and that of others follow each other in rapid succession. Effects of the surrounding context on speech perception are well documented but, despite the ubiquity of the sound of our own voice, it is unknown whether our own speech also influences our perception of other talkers. This study investigated context effects induced by our own speech through six experiments, specifically targeting rate normalization (i.e., perceiving phonetic segments relative to surrounding speech rate). Experiment 1 revealed that hearing pre-recorded fast or slow context sentences altered the perception of ambiguous vowels, replicating earlier work. Experiment 2 demonstrated that talking at a fast or slow rate prior to target presentation also altered target perception, though the effect of preceding speech rate was reduced. Experiment 3 showed that silent talking (i.e., inner speech) at fast or slow rates did not modulate the perception of others, suggesting that the effect of self-produced speech rate in Experiment 2 arose through monitoring of the external speech signal. Experiment 4 demonstrated that, when participants were played back their own (fast/slow) speech, no reduction of the effect of preceding speech rate was observed, suggesting that the additional task of speech production may be responsible for the reduced effect in Experiment 2. Finally, Experiments 5 and 6 replicate Experiments 2 and 3 with new participant samples. Taken together, these results suggest that variation in speech production may induce variation in speech perception, thus carrying implications for our understanding of spoken communication in dialogue settings.

Abstract

During conversation, spoken utterances occur in rich acoustic contexts, including speech produced by our interlocutor(s) and speech we produced ourselves. Prosodic characteristics of the acoustic context have been known to influence speech perception in a contrastive fashion: for instance, a vowel presented in a fast context is perceived to have a longer duration than the same vowel in a slow context. Given the ubiquity of the sound of our own voice, it may be that our own speech rate - a common source of acoustic context - also influences our perception of the speech of others. Two experiments were designed to test this hypothesis. Experiment 1 replicated earlier contextual rate effects by showing that hearing pre-recorded fast or slow context sentences alters the perception of ambiguous Dutch target words. Experiment 2 then extended this finding by showing that talking at a fast or slow rate prior to the presentation of the target words also altered the perception of those words. These results suggest that between-talker variation in speech rate production may induce between-talker variation in speech perception, thus potentially explaining why interlocutors tend to converge on speech rate in dialogue settings.

Abstract

Speech is an acoustic signal with inherent amplitude modulations in the 1-9 Hz range. Recent models of speech perception propose that this rhythmic nature of speech is central to speech recognition. Moreover, rhythmic amplitude modulations have been shown to have beneficial effects on language processing and the subjective impression listeners have of the speaker. This study investigated the role of amplitude modulations in the political arena by comparing the speech produced by Hillary Clinton and Donald Trump in the three presidential debates of 2016. Inspection of the modulation spectra, revealing the spectral content of the two speakers’ amplitude envelopes after matching for overall intensity, showed considerably greater power in Clinton’s modulation spectra (compared to Trump’s) across the three debates, particularly in the 1-9 Hz range. The findings suggest that Clinton’s speech had a more pronounced temporal envelope with rhythmic amplitude modulations below 9 Hz, with a preference for modulations around 3 Hz. This may be taken as evidence for a more structured temporal organization of syllables in Clinton’s speech, potentially due to more frequent use of preplanned utterances. Outcomes are interpreted in light of the potential beneficial effects of a rhythmic temporal envelope on intelligibility and speaker perception.

Abstract

Electrically stimulating early visual cortex results in a visual percept known as a phosphene. Although phosphenes can be evoked by a wide range of electrode sizes and current amplitudes, they are invariably described as small. To better understand this observation, we electrically stimulated 93 electrodes implanted in the visual cortex of 13 human subjects who reported phosphene size while stimulation current was varied. Phosphene size increased as the stimulation current was initially raised above threshold, but then rapidly reached saturation. Phosphene size also depended on the location of the stimulated site, with size increasing with distance from the foveal representation. We developed a model relating phosphene size to the amount of activated cortex and its location within the retinotopic map. First, a sigmoidal curve was used to predict the amount of activated cortex at a given current. Second, the amount of active cortex was converted to degrees of visual angle by multiplying by the inverse cortical magnification factor for that retinotopic location. This simple model accurately predicted phosphene size for a broad range of stimulation currents and cortical locations. The unexpected saturation in phosphene sizes suggests that the functional architecture of cerebral cortex may impose fundamental restrictions on the spread of artificially evoked activity and this may be an important consideration in the design of cortical prosthetic devices.

Abstract

A central motif in neuronal networks is convergence, linking several input neurons to one target neuron. In visual cortex, convergence renders target neurons responsive to complex stimuli. Yet, convergence typically sends multiple stimuli to a target, and the behaviorally relevant stimulus must be selected. We used two stimuli, activating separate electrocorticographic V1 sites, and both activating an electrocorticographic V4 site equally strongly. When one of those stimuli activated one V1 site, it gamma synchronized (60-80 Hz) to V4. When the two stimuli activated two V1 sites, primarily the relevant one gamma synchronized to V4. Frequency bands of gamma activities showed substantial overlap containing the band of interareal coherence. The relevant V1 site had its gamma peak frequency 2-3 Hz higher than the irrelevant V1 site and 4-6 Hz higher than V4. Gamma-mediated interareal influences were predominantly directed from V1 to V4. We propose that selective synchronization renders relevant input effective, thereby modulating effective connectivity.

Abstract

The primary aim of this paper is to assess patterns of morphological variation in the mandible to investigate changes during the last 500 years in the Netherlands. Three-dimensional geometric morphometrics is used on data collected from adults from three populations living in the Netherlands during three time-periods. Two of these samples come from Dutch archaeological sites (Alkmaar, 1484-1574, n = 37; and Middenbeemster, 1829-1866, n = 51) and were digitized using a 3D laser scanner. The third is a modern sample obtained from MRI scans of 34 modern Dutch individuals. Differences between mandibles are dominated by size. Significant differences in size are found among samples, with on average, males from Alkmaar having the largest mandibles and females from Middenbeemster having the smallest. The results are possibly linked to a softening of the diet, due to a combination of differences in food types and food processing that occurred between these time-periods. Differences in shape are most noticeable between males from Alkmaar and Middenbeemster. Shape differences between males and females are concentrated in the symphysis and ramus, which is mostly the consequence of sexual dimorphism. The relevance of this research is a better understanding of the anatomical variation of the mandible that can occur over an evolutionarily short time, as well as supporting research that has shown plasticity of the mandibular form related to diet and food processing. This plasticity of form must be taken into account in phylogenetic research and when the mandible is used in sex estimation of skeletons.

Abstract

Relational grammar was proposed in Suppes (1976) as a semantical grammar for natural language. Fragments considered so far are restricted to distributive notions. In this article, relational grammar is extended to collective notions.