Publications

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

Communication is facilitated when listeners allocate their attention to important information (focus) in the message, a process called "information structure." Linguistic cues like the preceding context and pitch accent help listeners to identify focused information. In multimodal communication, relevant information can be emphasized by nonverbal cues like beat gestures, which represent rhythmic nonmeaningful hand movements. Recent studies have found that linguistic and nonverbal attention cues are integrated independently in single sentences. However, it is possible that these two cues interact when information is embedded in context, because context allows listeners to predict what information is important. In an ERP study, we tested this hypothesis and asked listeners to view videos capturing a dialogue. In the critical sentence, focused and nonfocused words were accompanied by beat gestures, grooming hand movements, or no gestures. ERP results showed that focused words are processed more attentively than nonfocused words as reflected in an N1 and P300 component. Hand movements also captured attention and elicited a P300 component. Importantly, beat gesture and focus interacted in a late time window of 600-900 msec relative to target word onset, giving rise to a late positivity when nonfocused words were accompanied by beat gestures. Our results show that listeners integrate beat gesture with the focus of the message and that integration costs arise when beat gesture falls on nonfocused information. This suggests that beat gestures fulfill a unique focusing function in multimodal discourse processing and that they have to be integrated with the information structure of the message.

Abstract

People often accommodate to each other's speech by aligning their linguistic production with their partner's. According to an influential theory, the Interactive Alignment Model (Pickering & Garrod, 2004), alignment is the result of priming. When people perceive an utterance, the corresponding linguistic representations are primed, and become easier to produce. Here we tested this theory by investigating whether pitch (F0) alignment shows two characteristic signatures of priming: dose dependence and persistence. In a virtual reality experiment, we manipulated the pitch of a virtual interlocutor's speech to find out (a.) whether participants accommodated to the agent's F0, (b.) whether the amount of accommodation increased with increasing exposure to the agent's speech, and (c.) whether changes to participants' F0 persisted beyond the conversation. Participants accommodated to the virtual interlocutor, but accommodation did not increase in strength over the conversation, and it disappeared immediately after the conversation ended. Results argue against a priming-based account of F0 accommodation, and indicate that an alternative mechanism is needed to explain alignment along continuous dimensions of language such as speech rate and pitch.

Abstract

A neurobiological model of language is discussed that overcomes the shortcomings of the classical Wernicke-Lichtheim-Geschwind model. It is based on a subdivision of language processing into three components: Memory, Unification, and Control. The functional components as well as the neurobiological underpinnings of the model are discussed. In addition, the need for extension beyond the classical core regions for language is shown. Attentional networks as well as networks for inferential processing are crucial to realize language comprehension beyond single word processing and beyond decoding propositional content.

Abstract

Personal pronouns have been shown to influence cognitive perspective taking during comprehension. Studies using single sentences found that 3rd person pronouns facilitate the construction of a mental model from an observer’s perspective, whereas 2nd person pronouns support an actor’s perspective. The direction of the effect for 1st person pronouns seems to depend on the situational context. In the present study, we investigated how personal pronouns influence discourse comprehension when people read fiction stories and if this has consequences for affective components like emotion during reading or appreciation of the story. We wanted to find out if personal pronouns affect immersion and arousal, as well as appreciation of fiction. In a natural reading paradigm, we measured electrodermal activity and story immersion, while participants read literary stories with 1st and 3rd person pronouns referring to the protagonist. In addition, participants rated and ranked the stories for appreciation. Our results show that stories with 1st person pronouns lead to higher immersion. Two factors—transportation into the story world and mental imagery during reading—in particular showed higher scores for 1st person as compared to 3rd person pronoun stories. In contrast, arousal as measured by electrodermal activity seemed tentatively higher for 3rd person pronoun stories. The two measures of appreciation were not affected by the pronoun manipulation. Our findings underscore the importance of perspective for language processing, and additionally show which aspects of the narrative experience are influenced by a change in perspective.

Abstract

The Profile of Music Perception Skills (PROMS) is a recently developed measure of perceptual music skills which has been shown to have promising psychometric properties. In this paper we extend the evaluation of its brief version to three kinds of validity using an individual difference approach. The brief PROMS displays good discriminant validity with working memory, given that it does not correlate with backward digit span (r = .04). Moreover, it shows promising criterion validity (association with musical training (r = .45), musicianship status (r = .48), and self-rated musical talent (r = .51)). Finally, its convergent validity, i.e. relation to an unrelated measure of music perception skills, was assessed by correlating the brief PROMS to harmonic closure judgment accuracy. Two independent samples point to good convergent validity of the brief PROMS (r = .36; r = .40). The same association is still significant in one of the samples when including self-reported music skill in a partial correlation (rpartial = .30; rpartial = .17). Overall, the results show that the brief version of the PROMS displays a very good pattern of construct validity. Especially its tuning subtest stands out as a valuable part for music skill evaluations in Western samples. We conclude by briefly discussing the choice faced by music cognition researchers between different musical aptitude measures of which the brief PROMS is a well evaluated example.

Abstract

Many studies have revealed shared music–language processing resources by finding an influence of music harmony manipulations on concurrent language processing. However, the nature of the shared resources has remained ambiguous. They have been argued to be syntax specific and thus due to shared syntactic integration resources. An alternative view regards them as related to general attention and, thus, not specific to syntax. The present experiments evaluated these accounts by investigating the influence of language on music. Participants were asked to provide closure judgements on harmonic sequences in order to assess the appropriateness of sequence endings. At the same time participants read syntactic garden-path sentences. Closure judgements revealed a change in harmonic processing as the result of reading a syntactically challenging word. We found no influence of an arithmetic control manipulation (experiment 1) or semantic garden-path sentences (experiment 2). Our results provide behavioural evidence for a specific influence of linguistic syntax processing on musical harmony judgements. A closer look reveals that the shared resources appear to be needed to hold a harmonic key online in some form of syntactic working memory or unification workspace related to the integration of chords and words. Overall, our results support the syntax specificity of shared music–language processing resources.

Abstract

We used magnetoencephalography (MEG) to explore the spatio-temporal dynamics of neural oscillations associated with sentence processing, in 102 participants. We quantified changes in oscillatory power as the sentence unfolded, and in response to individual words in the sentence. For words early in a sentence compared to those late in the same sentence, we observed differences in left temporal and frontal areas, and bilateral frontal and right parietal regions for the theta, alpha, and beta frequency bands. The neural response to words in a sentence differed from the response to words in scrambled sentences in left-lateralized theta, alpha, beta, and gamma. The theta band effects suggest that a sentential context facilitates lexical retrieval, and that this facilitation is stronger for words late in the sentence. Effects in the alpha and beta band may reflect the unification of semantic and syntactic information, and are suggestive of easier unification late in a sentence. The gamma oscillations are indicative of predicting the upcoming word during sentence processing. In conclusion, changes in oscillatory neuronal activity capture aspects of sentence processing. Our results support earlier claims that language (sentence) processing recruits areas distributed across both hemispheres, and extends beyond the classical language regions

Abstract

Sound symbolism is increasingly understood as involving iconicity, or perceptual analogies and cross-modal correspondences between form and meaning, but the search for its functional and neural correlates is ongoing. Here we study how people learn sound-symbolic words, using behavioural, electrophysiological and individual difference measures. Dutch participants learned Japanese ideophones —lexical sound-symbolic words— with a translation of either the real meaning (in which form and meaning show cross-modal correspondences) or the opposite meaning (in which form and meaning show cross-modal clashes). Participants were significantly better at identifying the words they learned in the real condition, correctly remembering the real word pairing 86.7% of the time, but the opposite word pairing only 71.3% of the time. Analysing event-related potentials (ERPs) during the test round showed that ideophones in the real condition elicited a greater P3 component and late positive complex than ideophones in the opposite condition. In a subsequent forced choice task, participants were asked to guess the real translation from two alternatives. They did this with 73.0% accuracy, well above chance level even for words they had encountered in the opposite condition, showing that people are generally sensitive to the sound-symbolic cues in ideophones. Individual difference measures showed that the ERP effect in the test round of the learning task was greater for participants who were more sensitive to sound symbolism in the forced choice task. The main driver of the difference was a lower amplitude of the P3 component in response to ideophones in the opposite condition, suggesting that people who are more sensitive to sound symbolism may have more difficulty to suppress conflicting cross-modal information. The findings provide new evidence that cross-modal correspondences between sound and meaning facilitate word learning, while cross-modal clashes make word learning harder, especially for people who are more sensitive to sound symbolism.

Abstract

The existence of sound-symbolism (or a non-arbitrary link between form and meaning) is well-attested. However, sound-symbolism has mostly been investigated with nonwords in forced choice tasks, neither of which are representative of natural language. This study uses ideophones, which are naturally occurring sound-symbolic words that depict sensory information, to investigate how sensitive Dutch speakers are to sound-symbolism in Japanese in a learning task. Participants were taught 2 sets of Japanese ideophones; 1 set with the ideophones’ real meanings in Dutch, the other set with their opposite meanings. In Experiment 1, participants learned the ideophones and their real meanings much better than the ideophones with their opposite meanings. Moreover, despite the learning rounds, participants were still able to guess the real meanings of the ideophones in a 2-alternative forced-choice test after they were informed of the manipulation. This shows that natural language sound-symbolism is robust beyond 2-alternative forced-choice paradigms and affects broader language processes such as word learning. In Experiment 2, participants learned regular Japanese adjectives with the same manipulation, and there was no difference between real and opposite conditions. This shows that natural language sound-symbolism is especially strong in ideophones, and that people learn words better when form and meaning match. The highlights of this study are as follows: (a) Dutch speakers learn real meanings of Japanese ideophones better than opposite meanings, (b) Dutch speakers accurately guess meanings of Japanese ideophones, (c) this sensitivity happens despite learning some opposite pairings, (d) no such learning effect exists for regular Japanese adjectives, and (e) this shows the importance of sound-symbolism in scaffolding language learning

Abstract

Studies of sound symbolism have shown that people can associate sound and meaning in consistent ways when presented with maximally contrastive stimulus pairs of nonwords such as bouba/kiki (rounded/sharp) or mil/mal (small/big). Recent work has shown the effect extends to antonymic words from natural languages and has proposed a role for shared cross-modal correspondences in biasing form-to-meaning associations. An important open question is how the associations work, and particularly what the role is of sound-symbolic matches versus mismatches. We report on a learning task designed to distinguish between three existing theories by using a spectrum of sound-symbolically matching, mismatching, and neutral (neither matching nor mismatching) stimuli. Synthesized stimuli allow us to control for prosody, and the inclusion of a neutral condition allows a direct test of competing accounts. We find evidence for a sound-symbolic match boost, but not for a mismatch difficulty compared to the neutral condition.

Abstract

The way we talk can influence how we are perceived by others. Whereas previous studies have started to explore the influence of social goals on syntactic alignment, in the current study, we additionally investigated whether syntactic alignment effectively influences conversation partners’ perception of the speaker. To this end, we developed a novel paradigm in which we can measure the effect of social goals on the strength of syntactic alignment for one participant (primed participant), while simultaneously obtaining usable social opinions about them from their conversation partner (the evaluator). In Study 1, participants’ desire to be rated favorably by their partner was manipulated by assigning pairs to a Control (i.e., primed participants did not know they were being evaluated) or Evaluation context (i.e., primed participants knew they were being evaluated). Surprisingly, results showed no significant difference in the strength with which primed participants aligned their syntactic choices with their partners’ choices. In a follow-up study, we used a Directed Evaluation context (i.e., primed participants knew they were being evaluated and were explicitly instructed to make a positive impression). However, again, there was no evidence supporting the hypothesis that participants’ desire to impress their partner influences syntactic alignment. With respect to the influence of syntactic alignment on perceived likeability by the evaluator, a negative relationship was reported in Study 1: the more primed participants aligned their syntactic choices with their partner, the more that partner decreased their likeability rating after the experiment. However, this effect was not replicated in the Directed Evaluation context of Study 2. In other words, our results do not support the conclusion that speakers’ desire to be liked affects how much they align their syntactic choices with their partner, nor is there convincing evidence that there is a reliable relationship between syntactic alignment and perceived likeability.

Abstract

Verbal interaction is one of the most frequent social interactions humans encounter on a daily basis. In the current paper, we zoom in on what the multi-brain approach has contributed, and can contribute in the future, to our understanding of the neural mechanisms supporting verbal interaction. Indeed, since verbal interaction can only exist between individuals, it seems intuitive to focus analyses on inter-individual neural markers, i.e. between-brain neural coupling. To date, however, there is a severe lack of theoretically-driven, testable hypotheses about what between-brain neural coupling actually reflects. In this paper, we develop a testable hypothesis in which between-pair variation in between-brain neural coupling is of key importance. Based on theoretical frameworks and empirical data, we argue that the level of between-brain neural coupling reflects speaker-listener alignment at different levels of linguistic and extra-linguistic representation. We discuss the possibility that between-brain neural coupling could inform us about the highest level of inter-speaker alignment: mutual understanding

Abstract

We investigated whether structural priming of production latencies is sensitive to the same factors known to influence persistence of structural choices: structure preference, cumulativity and verb repetition. In two experiments, we found structural persistence only for passives (inverse preference effect) while priming effects on latencies were stronger for the actives (positive preference effect). We found structural persistence for passives to be influenced by immediate primes and long lasting cumulativity (all preceding primes) (Experiment 1), and to be boosted by verb repetition (Experiment 2). In latencies we found effects for actives were sensitive to long lasting cumulativity (Experiment 1). In Experiment 2, in latencies we found priming for actives overall, while for passives the priming effects emerged as the cumulative exposure increased but only when also aided by verb repetition. These findings are consistent with the Two-stage Competition model, an integrated model of structural priming effects for sentence choice and latency

Abstract

Fluctuations in pupil size have been shown to reflect variations in processing demands during lexical and syntactic processing in language comprehension. An issue that has not received attention is whether pupil size also varies due to pragmatic manipulations. In two pupillometry experiments, we investigated whether pupil diameter was sensitive to increased processing demands as a result of comprehending an indirect request versus a direct statement. Adult participants were presented with 120 picture–sentence combinations that could be interpreted either as an indirect request (a picture of a window with the sentence “it's very hot here”) or as a statement (a picture of a window with the sentence “it's very nice here”). Based on the hypothesis that understanding indirect utterances requires additional inferences to be made on the part of the listener, we predicted a larger pupil diameter for indirect requests than statements. The results of both experiments are consistent with this expectation. We suggest that the increase in pupil size reflects additional processing demands for the comprehension of indirect requests as compared to statements. This research demonstrates the usefulness of pupillometry as a tool for experimental research in pragmatics

Abstract

In order to communicate successfully, speakers have to take into account which information they share with their addressee, i.e. common ground. In the current experiment we investigated how and when common ground affects speech planning by tracking speakers’ eye movements while they played a referential communication game. We found evidence that common ground exerts an early, but incomplete effect on speech planning. In addition, we did not find longer planning times when speakers had to take common ground into account, suggesting that taking common ground into account is not necessarily an effortful process. Common ground information thus appears to act as a partial constraint on language production that is integrated flexibly and efficiently in the speech planning process.

Abstract

When learning a new language, we build brain networks to process and represent the acquired words and syntax and integrate these with existing language representations. It is an open question whether the same or different neural mechanisms are involved in learning and processing a novel language compared to the native language(s). Here we investigated the neural repetition effects of repeating known and novel word orders while human subjects were in the early stages of learning a new language. Combining a miniature language with a syntactic priming paradigm, we examined the neural correlates of language learning online using functional magnetic resonance imaging (fMRI). In left inferior frontal gyrus (LIFG) and posterior temporal cortex the repetition of novel syntactic structures led to repetition enhancement, while repetition of known structures resulted in repetition suppression. Additional verb repetition led to an
increase in the syntactic repetition enhancement effect in language-related brain regions. Similarly the repetition of verbs led to repetition enhancement effects in areas related to lexical and semantic processing, an effect that continued to increase in a subset of these regions. Repetition enhancement might reflect a mechanism to build and strengthen a neural network to process novel syntactic structures and lexical items. By contrast, the observed repetition suppression points to overlapping neural mechanisms for native and new language constructions when these have sufficient structural similarities.

Abstract

When we learn a second language later in life do we integrate it with the established neural networks in place for the first language or is at least a partially new network recruited? While there is evidence that simple grammatical structures in a second language share a system with the native language, the story becomes more multifaceted for complex sentence structures. In this study we investigated the underlying brain networks in native speakers compared to proficient second language users while processing complex sentences. As hypothesized, complex structures were processed by the same large-scale inferior frontal and middle temporal language networks of the brain in the second language, as seen in native speakers. These effects were seen both in activations as well as task-related connectivity patterns. Furthermore, the second language users showed increased task-related connectivity from inferior frontal to inferior parietal regions of the brain, regions related to attention and cognitive control, suggesting less automatic processing for these structures in a second language.

Abstract

The notion of prediction is studied in cognitive neuroscience with increasing intensity. We investigated the neural basis of 2 distinct aspects of word prediction, derived from information theory, during story comprehension. We assessed the effect of entropy of next-word probability distributions as well as surprisal. A computational model determined entropy and surprisal for each word in 3 literary stories. Twenty-four healthy participants listened to the same 3 stories while their brain activation was measured using fMRI. Reversed speech fragments were presented as a control condition. Brain areas sensitive to entropy were left ventral premotor cortex, left middle frontal gyrus, right inferior frontal gyrus, left inferior parietal lobule, and left supplementary motor area. Areas sensitive to surprisal were left inferior temporal sulcus (“visual word form area”), bilateral superior temporal gyrus, right amygdala, bilateral anterior temporal poles, and right inferior frontal sulcus. We conclude that prediction during language comprehension can occur at several levels of processing, including at the level of word form. Our study exemplifies the power of combining computational linguistics with cognitive neuroscience, and additionally underlines the feasibility of studying continuous spoken language materials with fMRI.

Abstract

A number of recent studies have hypothesized that monitoring in speech production may occur via domain-general mechanisms responsible for the detection of response conflict. Outside of language, two ERP components have consistently been elicited in conflict-inducing tasks (e.g., the flanker task): the stimulus-locked N2 on correct trials, and the response-locked error-related negativity (ERN). The present investigation used these electrophysiological markers to test whether a common response conflict monitor is responsible for monitoring in speech and non-speech tasks. Electroencephalography (EEG) was recorded while participants performed a tongue twister (TT) task and a manual version of the flanker task. In the TT task, people rapidly read sequences of four nonwords arranged in TT and non-TT patterns three times. In the flanker task, people responded with a left/right button press to a center-facing arrow, and conflict was manipulated by the congruency of the flanking arrows. Behavioral results showed typical effects of both tasks, with increased error rates and slower speech onset times for TT relative to non-TT trials and for incongruent relative to congruent flanker trials. In the flanker task, stimulus-locked EEG analyses replicated previous results, with a larger N2 for incongruent relative to congruent trials, and a response-locked ERN. In the TT task, stimulus-locked analyses revealed broad, frontally-distributed differences beginning around 50 ms and lasting until just before speech initiation, with TT trials more negative than non-TT trials; response-locked analyses revealed an ERN. Correlation across these measures showed some correlations within a task, but little evidence of systematic cross-task correlation. Although the present results do not speak against conflict signals from the production system serving as cues to self-monitoring, they are not consistent with signatures of response conflict being mediated by a single, domain-general conflict monitor

Abstract

Even though language allows us to say exactly what we mean, we often use language to say things indirectly, in a way that depends on the specific communicative context. For example, we can use an apparently straightforward sentence like "It is hard to give a good presentation" to convey deeper meanings, like "Your talk was a mess!" One of the big puzzles in language science is how listeners work out what speakers really mean, which is a skill absolutely central to communication. However, most neuroimaging studies of language comprehension have focused on the arguably much simpler, context-independent process of understanding direct utterances. To examine the neural systems involved in getting at contextually constrained indirect meaning, we used functional magnetic resonance imaging as people listened to indirect replies in spoken dialog. Relative to direct control utterances, indirect replies engaged dorsomedial prefrontal cortex, right temporo-parietal junction and insula, as well as bilateral inferior frontal gyrus and right medial temporal gyrus. This suggests that listeners take the speaker's perspective on both cognitive (theory of mind) and affective (empathy-like) levels. In line with classic pragmatic theories, our results also indicate that currently popular "simulationist" accounts of language comprehension fail to explain how listeners understand the speaker's intended message.

Abstract

Heschl's gyrus (HG) is a core region of the auditory cortex whose morphology is highly variable across individuals. This variability has been linked to sound perception ability in both speech and music domains. Previous studies show that variations in morphological features of HG, such as cortical surface area and thickness, are heritable. To identify genetic variants that affect HG morphology, we conducted a genome-wide association scan (GWAS) meta-analysis in 3054 healthy individuals using HG surface area and thickness as quantitative traits. None of the single nucleotide polymorphisms (SNPs) showed association P values that would survive correction for multiple testing over the genome. The most significant association was found between right HG area and SNP rs72932726 close to gene DCBLD2 (3q12.1; P=2.77x10(-7)). This SNP was also associated with other regions involved in speech processing. The SNP rs333332 within gene KALRN (3q21.2; P=2.27x10(-6)) and rs143000161 near gene COBLL1 (2q24.3; P=2.40x10(-6)) were associated with the area and thickness of left HG, respectively. Both genes are involved in the development of the nervous system. The SNP rs7062395 close to the X-linked deafness gene POU3F4 was associated with right HG thickness (Xq21.1; P=2.38x10(-6)). This is the first molecular genetic analysis of variability in HG morphology

Abstract

Language and action systems are highly interlinked. A critical piece of evidence is that speech and its accompanying gestures are tightly synchronized. Five experiments were conducted to test 2 hypotheses about the synchronization of speech and gesture. According to the interactive view, there is continuous information exchange between the gesture and speech systems, during both their planning and execution phases. According to the ballistic view, information exchange occurs only during the planning phases of gesture and speech, but the 2 systems become independent once their execution has been initiated. In all experiments, participants were required to point to and/or name a light that had just lit up. Virtual reality and motion tracking technologies were used to disrupt their gesture or speech execution. Participants delayed their speech onset when their gesture was disrupted. They did so even when their gesture was disrupted at its late phase and even when they received only the kinesthetic feedback of their gesture. Also, participants prolonged their gestures when their speech was disrupted. These findings support the interactive view and add new constraints on models of speech and gesture production

Abstract

There are increasing reports that individual variation in behavioral and neurophysiological measures of infant speech processing predicts later language outcomes, and specifically concurrent or subsequent vocabulary size. If such findings are held up under scrutiny, they could both illuminate theoretical models of language development and contribute to the prediction of communicative disorders. A qualitative, systematic review of this emergent literature illustrated the variety of approaches that have been used and highlighted some conceptual problems regarding the measurements. A quantitative analysis of the same data established that the bivariate relation was significant, with correlations of similar strength to those found for well-established nonlinguistic predictors of language. Further exploration of infant speech perception predictors, particularly from a methodological perspective, is recommended.

Abstract

Numerous experiments show that space and musical pitch are
closely linked in people's minds. However, the exact nature of
space-pitch associations and their neuronal underpinnings are
not well understood. In an fMRI experiment we investigated
different types of spatial representations that may underlie
musical pitch. Participants judged stimuli that varied in
spatial height in both the visual and tactile modalities, as well
as auditory stimuli that varied in pitch height. In order to
distinguish between unimodal and multimodal spatial bases of
musical pitch, we examined whether pitch activations were
present in modality-specific (visual or tactile) versus
multimodal (visual and tactile) regions active during spatial
height processing. Judgments of musical pitch were found to
activate unimodal visual areas, suggesting that space-pitch
associations may involve modality-specific spatial
representations, supporting a key assumption of embodied
theories of metaphorical mental representation.

Abstract

The left and right sides of the human brain are specialized for different kinds of information processing, and much of our cognition is lateralized to an extent towards one side or the other. Handedness is a reflection of nervous system lateralization. Roughly ten percent of people are mixed- or left-handed, and they show an elevated rate of reductions or reversals of some cerebral functional asymmetries compared to right-handers. Brain anatomical correlates of left-handedness have also been suggested. However, the relationships of left-handedness to brain structure and function remain far from clear. We carried out a comprehensive analysis of cortical surface area differences between 106 left-handed subjects and 1960 right-handed subjects, measured using an automated method of regional parcellation (FreeSurfer, Destrieux atlas). This is the largest study sample that has so far been used in relation to this issue. No individual cortical region showed an association with left-handedness that survived statistical correction for multiple testing, although there was a nominally significant association with the surface area of a previously implicated region: the left precentral sulcus. Identifying brain structural correlates of handedness may prove useful for genetic studies of cerebral asymmetries, as well as providing new avenues for the study of relations between handedness, cerebral lateralization and cognition.

Abstract

Functional and anatomical asymmetries are prevalent features of the human brain, linked to gender, handedness, and cognition. However, little is known about the neurodevelopmental processes involved. In zebrafish, asymmetries arise in the diencephalon before extending within the central nervous system. We aimed to identify genes involved in the development of subtle, left-right volumetric asymmetries of human subcortical structures using large datasets. We first tested the feasibility of measuring left-right volume differences in such large-scale samples, as assessed by two automated methods of subcortical segmentation (FSL|FIRST and FreeSurfer), using data from 235 subjects who had undergone MRI twice. We tested the agreement between the first and second scan, and the agreement between the segmentation methods, for measures of bilateral volumes of six subcortical structures and the hippocampus, and their volumetric asymmetries. We also tested whether there were biases introduced by left-right differences in the regional atlases used by the methods, by analyzing left-right flipped images. While many bilateral volumes were measured well (scan-rescan r = 0.6-0.8), most asymmetries, with the exception of the caudate nucleus, showed lower repeatabilites. We meta-analyzed genome-wide association scan results for caudate nucleus asymmetry in a combined sample of 3,028 adult subjects but did not detect associations at genome-wide significance (P < 5 × 10-8). There was no enrichment of genetic association in genes involved in left-right patterning of the viscera. Our results provide important information for researchers who are currently aiming to carry out large-scale genome-wide studies of subcortical and hippocampal volumes, and their asymmetries

Abstract

Current views on the neurobiological underpinnings of language are discussed that deviate in a number of ways from the classical Wernicke–Lichtheim–Geschwind model. More areas than Broca's and Wernicke's region are involved in language. Moreover, a division along the axis of language production and language comprehension does not seem to be warranted. Instead, for central aspects of language processing neural infrastructure is shared between production and comprehension. Three different accounts of the role of Broca's area in language are discussed. Arguments are presented in favor of a dynamic network view, in which the functionality of a region is co-determined by the network of regions in which it is embedded at particular moments in time. Finally, core regions of language processing need to interact with other networks (e.g. the attentional networks and the ToM network) to establish full functionality of language and communication.

Abstract

A hallmark of human language is that we combine lexical building blocks retrieved from memory in endless new ways. This combinatorial aspect of language is referred to as unification. Here we focus on the neurobiological infrastructure for syntactic and semantic unification. Unification is characterized by a high-speed temporal profile including both prediction and integration of retrieved lexical elements. A meta-analysis of numerous neuroimaging studies reveals a clear dorsal/ventral gradient in both left inferior frontal cortex and left posterior temporal cortex, with dorsal foci for syntactic processing and ventral foci for semantic processing. In addition to core areas for unification, further networks need to be recruited to realize language-driven communication to its full extent. One example is the theory of mind network, which allows listeners and readers to infer the intended message (speaker meaning) from the coded meaning of the linguistic utterance. This indicates that sensorimotor simulation cannot handle all of language processing.

Abstract

The use of virtual reality (VR) as a methodological tool is
becoming increasingly popular in behavioural research due
to its seemingly limitless possibilities. This new method has
not been used frequently in the field of psycholinguistics,
however, possibly due to the assumption that humancomputer
interaction does not accurately reflect human-human
interaction. In the current study we compare participants’
language behaviour in a syntactic priming task with human
versus avatar partners. Our study shows comparable priming
effects between human and avatar partners (Human: 12.3%;
Avatar: 12.6% for passive sentences) suggesting that VR is a
valid platform for conducting language research and studying
dialogue interactions.

Abstract

In human face-to-face communication, language comprehension is a multi-modal, situated activity. However, little is known about how we combine information from different modalities during comprehension, and how perceived communicative intentions, often signaled through visual signals, influence this process. We explored this question by simulating a multi-party communication context in which a speaker alternated her gaze between two recipients. Participants viewed speech-only or speech + gesture object-related messages when being addressed (direct gaze) or unaddressed (gaze averted to other participant). They were then asked to choose which of two object images matched the speaker’s preceding message. Unaddressed recipients responded significantly more slowly than addressees for speech-only utterances. However, perceiving the same speech accompanied by gestures sped unaddressed recipients up to a level identical to that of addressees. That is, when unaddressed recipients’ speech processing suffers, gestures can enhance the comprehension of a speaker’s message. We discuss our findings with respect to two hypotheses attempting to account for how social eye gaze may modulate multi-modal language comprehension.

Abstract

Most words that infants hear occur within fluent speech. To compile a vocabulary, infants therefore need to segment words from speech contexts. This study is the first to investigate whether infants (here: 10-month-olds) can recognize words when both initial exposure and test presentation are in continuous speech. Electrophysiological evidence attests that this indeed occurs: An increased extended negativity (word recognition effect) appears for familiarized target words relative to control words. This response proved constant at the individual level: Only infants who showed this negativity at test had shown such a response, within six repetitions after first occurrence, during familiarization.

Abstract

Morphology is the aspect of language concerned with the internal structure of words. In the past decades, a large body of masked priming (behavioral and neuroimaging) data has suggested that the visual word recognition system automatically decomposes any morphologically complex word into a stem and its constituent morphemes. Yet the reliance of morphology on other reading processes (e.g., orthography and semantics), as well as its underlying neuronal mechanisms are yet to be determined. In the current magnetoencephalography study, we addressed morphology from the perspective of the unification framework, that is, by applying the Hold/Release paradigm, morphological unification was simulated via the assembly of internal morphemic units into a whole word. Trials representing real words were divided into words with a transparent (true) or a nontransparent (pseudo) morphological relationship. Morphological unification of truly suffixed words was faster and more accurate and additionally enhanced induced oscillations in the narrow gamma band (60–85 Hz, 260–440 ms) in the left posterior occipitotemporal junction. This neural signature could not be explained by a mere automatic lexical processing (i.e., stem perception), but more likely it related to a semantic access step during the morphological unification process. By demonstrating the validity of unification at the morphological level, this study contributes to the vast empirical evidence on unification across other language processes. Furthermore, we point out that morphological unification relies on the retrieval of lexical semantic associations via induced gamma band oscillations in a cerebral hub region for visual word form processing.

Abstract

We report on an fMRI syntactic priming experiment in which we measure brain activity for participants who communicate with another participant outside the scanner. We investigated whether syntactic processing during overt language production and comprehension is influenced by having a (shared) goal to communicate. Although theory suggests this is true, the nature of this influence remains unclear. Two hypotheses are tested: i. syntactic priming effects (fMRI and RT) are stronger for participants in the communicative context than for participants doing the same experiment in a non-communicative context, and ii. syntactic priming magnitude (RT) is correlated with the syntactic priming magnitude of the speaker’s communicative partner. Results showed that across conditions, participants were faster to produce sentences with repeated syntax, relative to novel syntax. This behavioral result converged with the fMRI data: we found repetition suppression effects in the left insula extending into left inferior frontal gyrus (BA 47/45), left middle temporal gyrus (BA 21), left inferior parietal cortex (BA 40), left precentral gyrus (BA 6), bilateral precuneus (BA 7), bilateral supplementary motor cortex (BA 32/8) and right insula (BA 47). We did not find support for the first hypothesis: having a communicative intention does not increase the magnitude of syntactic priming effects (either in the brain or in behavior) per se. We did find support for the second hypothesis: if speaker A is strongly/weakly primed by speaker B, then speaker B is primed by speaker A to a similar extent. We conclude that syntactic processing is influenced by being in a communicative context, and that the nature of this influence is bi-directional: speakers are influenced by each other.

Abstract

Speakers sometimes repeat syntactic structures across sentences, a phenomenon called syntactic priming. We investigated the influence of verb-bound syntactic preferences on syntactic priming effects in response choices and response latencies for German ditransitive sentences. In the response choices we found inverse preference effects: There were stronger syntactic priming effects for primes in the less preferred structure, given the syntactic preference of the prime verb. In the response latencies we found positive preference effects: There were stronger syntactic priming effects for primes in the more preferred structure, given the syntactic preference of the prime verb. These findings provide further support for the idea that syntactic processing is lexically guided.

Abstract

An ability to decode semantic information from fMRI spatial patterns has been demonstrated in previous studies mostly for 1 specific input modality. In this study, we aimed to decode semantic category independent of the modality in which an object was presented. Using a searchlight method, we were able to predict the stimulus category from the data while participants performed a semantic categorization task with 4 stimulus modalities (spoken and written names, photographs, and natural sounds). Significant classification performance was achieved in all 4 modalities. Modality-independent decoding was implemented by training and testing the searchlight method across modalities. This allowed the localization of those brain regions, which correctly discriminated between the categories, independent of stimulus modality. The analysis revealed large clusters of voxels in the left inferior temporal cortex and in frontal regions. These voxels also allowed category discrimination in a free recall session where subjects recalled the objects in the absence of external stimuli. The results show that semantic information can be decoded from the fMRI signal independently of the input modality and have clear implications for understanding the functional mechanisms of semantic memory.

Abstract

How can we understand each other during communicative interactions? An influential suggestion holds that communicators are primed by each other’s behaviors, with associative mechanisms automatically coordinating the production of communicative signals and the comprehension of their meanings. An alternative suggestion posits that mutual understanding requires shared conceptualizations of a signal’s use, i.e., “conceptual pacts” that are abstracted away from specific experiences. Both accounts predict coherent neural dynamics across communicators, aligned either to the occurrence of a signal or to the dynamics of conceptual pacts. Using coherence spectral-density analysis of cerebral activity simultaneously measured in pairs of communicators, this study shows that establishing mutual understanding of novel signals synchronizes cerebral dynamics across communicators’ right temporal lobes. This interpersonal cerebral coherence occurred only within pairs with a shared communicative history, and at temporal scales independent from signals’ occurrences. These findings favor the notion that meaning emerges from shared conceptualizations of a signal’s use.

Abstract

Despite the ambiguity inherent in human communication, people are remarkably efficient in establishing mutual understanding. Studying how people communicate in novel settings provides a window into the mechanisms supporting the human competence to rapidly generate and understand novel shared symbols, a fundamental property of human communication. Previous work indicates that the right posterior superior temporal sulcus (pSTS) is involved when people understand the intended meaning of novel communicative actions. Here, we set out to test whether normal functioning of this cerebral structure is required for understanding novel communicative actions using inhibitory low-frequency repetitive transcranial magnetic stimulation (rTMS). A factorial experimental design contrasted two tightly matched stimulation sites (right pSTS vs. left MT+, i.e. a contiguous homotopic task-relevant region) and tasks (a communicative task vs. a visual tracking task that used the same sequences of stimuli). Overall task performance was not affected by rTMS, whereas changes in task performance over time were disrupted according to TMS site and task combinations. Namely, rTMS over pSTS led to a diminished ability to improve action understanding on the basis of recent communicative history, while rTMS over MT+ perturbed improvement in visual tracking over trials. These findings qualify the contributions of the right pSTS to human communicative abilities, showing that this region might be necessary for incorporating previous knowledge, accumulated during interactions with a communicative partner, to constrain the inferential process that leads to action understanding.

Abstract

To investigate the neural underpinnings of word decoding, and how it changes as a function of repeated exposure, we trained Dutch participants repeatedly over the course of a month of training to articulate a set of novel disyllabic input strings written in Greek script to avoid the use of familiar orthographic representations. The syllables in the input were phonotactically legal combinations but non-existent in the Dutch language, allowing us to assess their role in novel word decoding. Not only trained disyllabic pseudowords were tested but also pseudowords with recombined patterns of syllables to uncover the emergence of syllabic representations. We showed that with extensive training, articulation became faster and more accurate for the trained pseudowords. On the neural level, the initial stage of decoding was reflected by increased activity in visual attention areas of occipito-temporal and occipito-parietal cortices, and in motor coordination areas of the precentral gyrus and the inferior frontal gyrus. After one month of training, memory representations for holistic information (whole word unit) were established in areas encompassing the angular gyrus, the precuneus and the middle temporal gyrus. Syllabic representations also emerged through repeated training of disyllabic pseudowords, such that reading recombined syllables of the trained pseudowords showed similar brain activation to trained pseudowords and were articulated faster than novel combinations of letter strings used in the trained pseudowords.

Abstract

In this fMRI study we investigate the neural correlates of information structure integration during sentence comprehension in Dutch. We looked into how prosodic cues (pitch accents) that signal the information status of constituents to the listener (new information) are combined with other types of information during the unification process. The difficulty of unifying the prosodic cues into overall sentence meaning was manipulated by constructing sentences in which the pitch accent did (focus-accent agreement), and sentences in which the pitch accent did not (focus-accent disagreement) match the expectations for focus constituents of the sentence. In case of a mismatch, the load on unification processes increases. Our results show two anatomically distinct effects of focus-accent disagreement, one located in the posterior left inferior frontal gyrus (LIFG, BA6/44), and one in the more anterior-ventral LIFG (BA 47/45). Our results confirm that information structure is taken into account during unification, and imply an important role for the LIFG in unification processes, in line with previous fMRI studies.

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

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

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

Research on pattern perception and rule learning, grounded in formal language theory (FLT) and using artificial grammar learning paradigms, has exploded in the last decade. This approach marries empirical research conducted by neuroscientists, psychologists and ethologists with the theory of computation and FLT, developed by mathematicians, linguists and computer scientists over the last century. Of particular current interest are comparative extensions of this work to non-human animals, and neuroscientific investigations using brain imaging techniques. We provide a short introduction to the history of these fields, and to some of the dominant hypotheses, to help contextualize these ongoing research programmes, and finally briefly introduce the papers in the current issue.

Abstract

Geen andere soort dan homo sapiens heeft in de loop van zijn evolutionaire geschiedenis een communicatiesysteem ontwikkeld waarin een eindig aantal symbolen samen met een reeks van regels voor het combineren daarvan een oneindig aantal uitdrukkingen mogelijk maakt. Dit natuurlijke taalsysteem stelt leden van onze soort in staat gedachten een uiterlijke vorm te geven en uit te wisselen met de sociale groep en, door de uitvinding van schriftsystemen, met de gehele samenleving. Spraak en taal zijn effectieve middelen voor het behoud van sociale cohesie in samenlevingen waarvan de groepsgrootte en de complexe sociale organisatie van dien aard is dat dit niet langer kan door middel van ‘vlooien’, de wijze waarop onze genetische buren, de primaten van de oude wereld, sociale cohesie bevorderen [1,2].

Abstract

Co-speech gestures are an integral part of human face-to-face communication, but little is known about how pragmatic factors influence our comprehension of those gestures. The present study investigates how different types of recipients process iconic gestures in a triadic communicative situation. Participants (N = 32) took on the role of one of two recipients in a triad and were presented with 160 video clips of an actor speaking, or speaking and gesturing. Crucially, the actor’s eye gaze was manipulated in that she alternated her gaze between the two recipients. Participants thus perceived some messages in the role of addressed recipient and some in the role of unaddressed recipient. In these roles, participants were asked to make judgements concerning the speaker’s messages. Their reaction times showed that unaddressed recipients did comprehend speaker’s gestures differently to addressees. The findings are discussed with respect to automatic and controlled processes involved in gesture comprehension.

Abstract

Around their first birthday infants begin to talk, yet they comprehend words long before. This study investigated the event-related potentials (ERP) responses of nine-month-olds on basic level picture-word pairings. After a familiarization phase of six picture-word pairings per semantic category, comprehension for novel exemplars was tested in a picture-word matching paradigm. ERPs time-locked to pictures elicited a modulation of the Negative Central (Nc) component, associated with visual attention and recognition. It was attenuated by category repetition as well as by the type-token ratio of picture context. ERPs time-locked to words in the training phase became more negative with repetition (N300-600), but there was no influence of picture type-token ratio, suggesting that infants have identified the concept of each picture before a word was presented. Results from the test phase provided clear support that infants integrated word meanings with (novel) picture context. Here, infants showed different ERP responses for words that did or did not align with the picture context: a phonological mismatch (N200) and a semantic mismatch (N400). Together, results were informative of visual categorization, word recognition and word-to-world-mappings, all three crucial processes for vocabulary construction.

Abstract

Infants’ ability to recognize words in continuous speech is vital for building a vocabulary.We here examined the amount and type
of exposure needed for 10-month-olds to recognize words. Infants first heard a word, either embedded within an utterance or in
isolation, then recognition was assessed by comparing event-related potentials to this word versus a word that they had not heard
directly before. Although all 10-month-olds showed recognition responses to words first heard in isolation, not all infants showed
such responses to words they had first heard within an utterance. Those that did succeed in the latter, harder, task, however,
understood more words and utterances when re-tested at 12 months, and understood more words and produced more words at
24 months, compared with those who had shown no such recognition response at 10 months. The ability to rapidly recognize the
words in continuous utterances is clearly linked to future language development.

Abstract

The genetic FOXP2-CNTNAP2 pathway has been shown to be involved in the language capacity. We investigated whether a common variant of CNTNAP2 (rs7794745) is relevant for syntactic and semantic processing in the general population by using a visual sentence processing paradigm while recording ERPs in 49 healthy adults. While both AA homozygotes and T-carriers showed a standard N400 effect to semantic anomalies, the response to subject-verb agreement violations differed across genotype groups. T-carriers displayed an anterior negativity preceding the P600 effect, whereas for the AA group only a P600 effect was observed. These results provide another piece of evidence that the neuronal architecture of the human faculty of language is shaped differently by effects that are genetically determined.

Abstract

It is well-known that, within ERP paradigms of sentence processing, semantically anomalous words elicit N400 effects. Less clear, however, is what happens after the N400. In some cases N400 effects are followed by Late Positive Complexes (LPC), whereas in other cases such effects are lacking. We investigated several factors which could affect the LPC, such as contextual constraint, inter-individual variation and working memory. Seventy-two participants read sentences containing a semantic manipulation (Whipped cream tastes sweet/anxious and creamy). Neither contextual constraint nor working memory correlated with the LPC. Inter-individual variation played a substantial role in the elicitation of the LPC with about half of the participants showing a negative response and the other half showing an LPC. This individual variation correlated with a syntactic ERP as well as an alternative semantic manipulation. In conclusion, our results show that inter-individual variation plays a large role in the elicitation of the LPC and this may account for the diversity in LPC findings in language research.

Abstract

When people see a snake, they are likely to activate both affective information (e.g., dangerous) and non-affective information about its ontological category (e.g., animal). According to the Affective Primacy Hypothesis, the affective information has priority, and its activation can precede identification of the ontological category of a stimulus. Alternatively, according to the Cognitive Primacy Hypothesis, perceivers must know what they are looking at before they can make an affective judgment about it. We propose that neither hypothesis holds at all times. Here we show that the relative speed with which affective and non-affective information gets activated by pictures and words depends upon the contexts in which stimuli are processed. Results illustrate that the question of whether affective information has processing priority over ontological information (or vice versa) is ill posed. Rather than seeking to resolve the debate over Cognitive vs. Affective Primacy in favor of one hypothesis or the other, a more productive goal may be to determine the factors that cause affective information to have processing priority in some circumstances and ontological information in others. Our findings support a view of the mind according to which words and pictures activate different neurocognitive representations every time they are processed, the specifics of which are co-determined by the stimuli themselves and the contexts in which they occur.

Abstract

In speaking, semantic encoding is the conversion of a non-verbal mental representation (the reference) into a semantic structure suitable for expression (the sense). In this fMRI study on sentence production we investigate how the speaking brain accomplishes this transition from non-verbal to verbal representations. In an overt picture description task, we manipulated repetition of sense (the semantic structure of the sentence) and reference (the described situation) separately. By investigating brain areas showing response adaptation to repetition of each of these sentence properties, we disentangle the neuronal infrastructure for these two components of semantic encoding. We also performed a control experiment with the same stimuli and design but without any linguistic task to identify areas involved in perception of the stimuli per se. The bilateral inferior parietal lobes were selectively sensitive to repetition of reference, while left inferior frontal gyrus showed selective suppression to repetition of sense. Strikingly, a widespread network of areas associated with language processing (left middle frontal gyrus, bilateral superior parietal lobes and bilateral posterior temporal gyri) all showed repetition suppression to both sense and reference processing. These areas are probably involved in mapping reference onto sense, the crucial step in semantic encoding. These results enable us to track the transition from non-verbal to verbal representations in our brains.

Abstract

Models of speaking distinguish producing meaning, words and syntax as three different linguistic components of speaking. Nevertheless, little is known about the brain’s integrated neuronal infrastructure for speech production. We investigated semantic, lexical and syntactic aspects of speaking using fMRI. In a picture description task, we manipulated repetition of sentence meaning, words, and syntax separately. By investigating brain areas showing response adaptation to repetition of each of these sentence properties, we disentangle the neuronal infrastructure for these processes. We demonstrate that semantic, lexical and syntactic processes are carried out in partly overlapping and partly distinct brain networks and show that the classic left-hemispheric dominance for language is present for syntax but not semantics.

Abstract

The human capacity to acquire language is an outstanding scientific challenge to understand. Somehow our language capacities arise from the way the human brain processes, develops and learns in interaction with its environment. To set the stage, we begin with a summary of what is known about the neural organization of language and what our artificial grammar learning (AGL) studies have revealed. We then review the Chomsky hierarchy in the context of the theory of computation and formal learning theory. Finally, we outline a neurobiological model of language acquisition and processing based on an adaptive, recurrent, spiking network architecture. This architecture implements an asynchronous, event-driven, parallel system for recursive processing. We conclude that the brain represents grammars (or more precisely, the parser/generator) in its connectivity, and its ability for syntax is based on neurobiological infrastructure for structured sequence processing. The acquisition of this ability is accounted for in an adaptive dynamical systems framework. Artificial language learning (ALL) paradigms might be used to study the acquisition process within such a framework, as well as the processing properties of the underlying neurobiological infrastructure. However, it is necessary to combine and constrain the interpretation of ALL results by theoretical models and empirical studies on natural language processing. Given that the faculty of language is captured by classical computational models to a significant extent, and that these can be embedded in dynamic network architectures, there is hope that significant progress can be made in understanding the neurobiology of the language faculty.

Abstract

In this paper we examine the neurobiological correlates of syntax, the processing of structured sequences, by comparing FMRI results on artificial and natural language syntax. We discuss these and similar findings in the context of formal language and computability theory. We used a simple right-linear unification grammar in an implicit artificial grammar learning paradigm in 32 healthy Dutch university students (natural language FMRI data were already acquired for these participants). We predicted that artificial syntax processing would engage the left inferior frontal region (BA 44/45) and that this activation would overlap with syntax-related variability observed in the natural language experiment. The main findings of this study show that the left inferior frontal region centered on BA 44/45 is active during artificial syntax processing of well-formed (grammatical) sequence independent of local subsequence familiarity. The same region is engaged to a greater extent when a syntactic violation is present and structural unification becomes difficult or impossible. The effects related to artificial syntax in the left inferior frontal region (BA 44/45) were essentially identical when we masked these with activity related to natural syntax in the same subjects. Finally, the medial temporal lobe was deactivated during this operation, consistent with the view that implicit processing does not rely on declarative memory mechanisms that engage the medial temporal lobe. In the context of recent FMRI findings, we raise the question whether Broca’s region (or subregions) is specifically related to syntactic movement operations or the processing of hierarchically nested non-adjacent dependencies in the discussion section. We conclude that this is not the case. Instead, we argue that the left inferior frontal region is a generic on-line sequence processor that unifies information from various sources in an incremental and recursive manner, independent of whether there are any processing requirements related to syntactic movement or hierarchically nested structures. In addition, we argue that the Chomsky hierarchy is not directly relevant for neurobiological systems.

Abstract

Human communication is often thought about in terms of transmitted messages in a conventional code like a language. But communication requires a specialized interactive intelligence. Senders have to be able to perform recipient design, while receivers need to be able to do intention recognition, knowing that recipient design has taken place. To study this interactive intelligence in the lab, we developed a new task that taps directly into the underlying abilities to communicate in the absence of a conventional code. We show that subjects are remarkably successful communicators under these conditions, especially when senders get feedback from receivers. Signaling is accomplished by the manner in which an instrumental action is performed, such that instrumentally dysfunctional components of an action are used to convey communicative intentions. The findings have important implications for the nature of the human communicative infrastructure, and the task opens up a line of experimentation on human communication.

Abstract

During speaking and listening syntactic processing is a crucial step. It involves specifying syntactic relations between words in a sentence. If the production and comprehension modality share the neuronal substrate for syntactic processing then processing syntax in one modality should lead to adaptation effects in the other modality. In the present functional magnetic resonance imaging experiment, participants either overtly produced or heard descriptions of pictures. We looked for brain regions showing adaptation effects to the repetition of syntactic structures. In order to ensure that not just the same brain regions but also the same neuronal populations within these regions are involved in syntactic processing in speaking and listening, we compared syntactic adaptation effects within processing modalities (syntactic production-to-production and comprehension-to-comprehension priming) with syntactic adaptation effects between processing modalities (syntactic comprehension-to-production and production-to-comprehension priming). We found syntactic adaptation effects in left inferior frontal gyrus (Brodmann's area [BA] 45), left middle temporal gyrus (BA 21), and bilateral supplementary motor area (BA 6) which were equally strong within and between processing modalities. Thus, syntactic repetition facilitates syntactic processing in the brain within and across processing modalities to the same extent. We conclude that that the same neurobiological system seems to subserve syntactic processing in speaking and listening.

Abstract

Identifying genetic variants influencing human brain structures may reveal new biological mechanisms underlying cognition and neuropsychiatric illness. The volume of the hippocampus is a biomarker of incipient Alzheimer's disease and is reduced in schizophrenia, major depression and mesial temporal lobe epilepsy. Whereas many brain imaging phenotypes are highly heritable, identifying and replicating genetic influences has been difficult, as small effects and the high costs of magnetic resonance imaging (MRI) have led to underpowered studies. Here we report genome-wide association meta-analyses and replication for mean bilateral hippocampal, total brain and intracranial volumes from a large multinational consortium. The intergenic variant rs7294919 was associated with hippocampal volume (12q24.22; N = 21,151; P = 6.70 × 10(-16)) and the expression levels of the positional candidate gene TESC in brain tissue. Additionally, rs10784502, located within HMGA2, was associated with intracranial volume (12q14.3; N = 15,782; P = 1.12 × 10(-12)). We also identified a suggestive association with total brain volume at rs10494373 within DDR2 (1q23.3; N = 6,500; P = 5.81 × 10(-7)).

Abstract

A recent hypothesis in empirical brain research on language is that the fundamental difference between animal and human communication systems is captured by the distinction between finite-state and more complex phrase-structure grammars, such as context-free and context-sensitive grammars. However, the relevance of this distinction for the study of language as a neurobiological system has been questioned and it has been suggested that a more relevant and partly analogous distinction is that between non-adjacent and adjacent dependencies. Online memory resources are central to the processing of non-adjacent dependencies as information has to be maintained across intervening material. One proposal is that an external memory device in the form of a limited push-down stack is used to process non-adjacent dependencies. We tested this hypothesis in an artificial grammar learning paradigm where subjects acquired non-adjacent dependencies implicitly. Generally, we found no qualitative differences between the acquisition of non-adjacent dependencies and adjacent dependencies. This suggests that although the acquisition of non-adjacent dependencies requires more exposure to the acquisition material, it utilizes the same mechanisms used for acquiring adjacent dependencies. We challenge the push-down stack model further by testing its processing predictions for nested and crossed multiple non-adjacent dependencies. The push-down stack model is partly supported by the results, and we suggest that stack-like properties are some among many natural properties characterizing the underlying neurophysiological mechanisms that implement the online memory resources used in language and structured sequence processing.

Abstract

When an adult claims he cannot sleep without his teddy bear, people tend to react surprised. Language interpretation is, thus, influenced by social context, such as who the speaker is. The present study reveals inter-individual differences in brain reactivity to social aspects of language. Whereas women showed brain reactivity when stereotype-based inferences about a speaker conflicted with the content of the message, men did not. This sex difference in social information processing can be explained by a specific cognitive trait, one’s ability to empathize. Individuals who empathize to a greater degree revealed larger N400 effects (as well as a larger increase in γ-band power) to socially relevant information. These results indicate that individuals with high-empathizing skills are able to rapidly integrate information about the speaker with the content of the message, as they make use of voice-based inferences about the speaker to process language in a top-down manner. Alternatively, individuals with lower empathizing skills did not use information about social stereotypes in implicit sentence comprehension, but rather took a more bottom-up approach to the processing of these social pragmatic sentences.

Abstract

Research from the past decade has shown that understanding the meaning of words and utterances (i.e., abstracted symbols) engages the same systems we used to perceive and interact with the physical world in a content-specific manner. For example, understanding the word “grasp” elicits activation in the cortical motor network, that is, part of the neural substrate involved in planned and executing a grasping action. In the embodied literature, cortical motor activation during language comprehension is thought to reflect motor simulation underlying conceptual knowledge [note that outside the embodied framework, other explanations for the link between action and language are offered, e.g., Mahon, B. Z., & Caramazza, A. A critical look at the embodied cognition hypothesis and a new proposal for grouding conceptual content. Journal of Physiology, 102, 59–70, 2008; Hagoort, P. On Broca, brain, and binding: A new framework. Trends in Cognitive Sciences, 9, 416–423, 2005]. Previous research has supported the view that the coupling between language and action is flexible, and reading an action-related word form is not sufficient for cortical motor activation [Van Dam, W. O., van Dijk, M., Bekkering, H., & Rueschemeyer, S.-A. Flexibility in embodied lexical–semantic representations. Human Brain Mapping, doi: 10.1002/hbm.21365, 2011]. The current study goes one step further by addressing the necessity of action-related word forms for motor activation during language comprehension. Subjects listened to indirect requests (IRs) for action during an fMRI session. IRs for action are speech acts in which access to an action concept is required, although it is not explicitly encoded in the language. For example, the utterance “It is hot here!” in a room with a window is likely to be interpreted as a request to open the window. However, the same utterance in a desert will be interpreted as a statement. The results indicate (1) that comprehension of IR sentences activates cortical motor areas reliably more than comprehension of sentences devoid of any implicit motor information. This is true despite the fact that IR sentences contain no lexical reference to action. (2) Comprehension of IR sentences also reliably activates substantial portions of the theory of mind network, known to be involved in making inferences about mental states of others. The implications of these findings for embodied theories of language are discussed.

Abstract

Rhyme processing is reflected in the electrophysiological signals of the brain as a negative deflection for non-rhyming as compared to rhyming stimuli around 450 ms after stimulus onset. Studies have shown that this N450 component is not solely sensitive to rhyme but also responds to other types of phonological overlap. In the present study, we examined whether the N450 component can be used to gain insight into the global similarity effect, indicating that rhyme judgment skills decrease when participants are presented with word pairs that share a phonological overlap but do not rhyme (e.g., bell–ball). We presented 20 adults with auditory rhyming, globally similar overlapping and unrelated word pairs. In addition to measuring behavioral responses by means of a yes/no button press, we also took EEG measures. The behavioral data showed a clear global similarity effect; participants judged overlapping pairs more slowly than unrelated pairs. However, the neural outcomes did not provide evidence that the N450 effect responds differentially to globally similar and unrelated word pairs, suggesting that globally similar and dissimilar non-rhyming pairs are processed in a similar fashion at the stage of early lexical access.

Abstract

The relationship between the evoked responses (ERPs/ERFs) and the event-related changes in EEG/MEG power that can be observed during sentence-level language comprehension is as yet unclear. This study addresses a possible relationship between MEG power changes and the N400m component of the event-related field. Whole-head MEG was recorded while subjects listened to spoken sentences with incongruent (IC) or congruent (C) sentence endings. A clear N400m was observed over the left hemisphere, and was larger for the IC sentences than for the C sentences. A time–frequency analysis of power revealed a decrease in alpha and beta power over the left hemisphere in roughly the same time range as the N400m for the IC relative to the C condition. A linear regression analysis revealed a positive linear relationship between N400m and beta power for the IC condition, not for the C condition. No such linear relation was found between N400m and alpha power for either condition. The sources of the beta decrease were estimated in the LIFG, a region known to be involved in semantic unification operations. One source of the N400m was estimated in the left superior temporal region, which has been related to lexical retrieval. We interpret our data within a framework in which beta oscillations are inversely related to the engagement of task-relevant brain networks. The source reconstructions of the beta power suppression and the N400m effect support the notion of a dynamic communication between the LIFG and the left superior temporal region during language comprehension.

Abstract

Information structure facilitates communication between interlocutors by highlighting relevant information. It has previously been shown that information structure modulates the depth of semantic processing. Here we used event-related potentials to investigate whether information structure can modulate the depth of syntactic processing. In question-answer pairs, subtle (number agreement) or salient (phrase structure) syntactic violations were placed either in focus or out of focus through information structure marking. P600 effects to these violations reflect the depth of syntactic processing. For subtle violations, a P600 effect was observed in the focus condition, but not in the non-focus condition. For salient violations, comparable P600 effects were found in both conditions. These results indicate that information structure can modulate the depth of syntactic processing, but that this effect depends on the salience of the information. When subtle violations are not in focus, they are processed less elaborately. We label this phenomenon the Chomsky illusion.

Abstract

We carried out the first study on the relationship between individual language aptitude and structural connectivity of language pathways in the adult brain. We measured four components of language aptitude (vocabulary learning, VocL; sound recognition, SndRec; sound-symbol correspondence, SndSym; and grammatical inferencing, GrInf) using the LLAMA language aptitude test (Meara, 2005). Spatial working memory (SWM), verbal working memory (VWM) and IQ were also measured as control factors. Diffusion Tensor Imaging (DTI) was employed to investigate the structural connectivity of language pathways in the perisylvian language network. Principal Component Analysis (PCA) on behavioural measures suggests that a general ability might be important to the first stages of L2 acquisition. It also suggested that VocL, SndSy and SWM are more closely related to general IQ than SndRec and VocL, and distinguished the tasks specifically designed to tap into L2 acquisition (VocL, SndRec,SndSym and GrInf) from more generic measures (IQ, SWM and VWM). Regression analysis suggested significant correlations between most of these behavioural measures and the structural connectivity of certain language pathways, i.e., VocL and BA47-Parietal pathway, SndSym and inter-hemispheric BA45 pathway, GrInf and BA45-Temporal pathway and BA6-Temporal pathway, IQ and BA44-Parietal pathway, BA47-Parietal pathway, BA47-Temporal pathway and inter-hemispheric BA45 pathway, SWM and inter-hemispheric BA6 pathway and BA47-Parietal pathway, and VWM and BA47-Temporal pathway. These results are discussed in relation to relevant findings in the literature.

Abstract

Semantic unification, the process by which small blocks of semantic information are combined into a coherent utterance, has been studied with various types of tasks. However, whether the brain activations reported in these studies are attributed to semantic unification per se or to other task-induced concomitant processes still remains unclear. The neural basis for semantic unification in sentence comprehension was examined using event-related potentials (ERP) and functional Magnetic Resonance Imaging (fMRI). The semantic unification load was manipulated by varying the goodness of fit between a critical word and its preceding context (in high cloze, low cloze and violation sentences). The sentences were presented in a serial visual presentation mode. The participants were asked to perform one of three tasks: semantic congruency judgment (SEM), silent reading for comprehension (READ), or font size judgment (FONT), in separate sessions. The ERP results showed a similar N400 amplitude modulation by the semantic unification load across all of the three tasks. The brain activations associated with the semantic unification load were found in the anterior left inferior frontal gyrus (aLIFG) in the FONT task and in a widespread set of regions in the other two tasks. These results suggest that the aLIFG activation reflects a semantic unification, which is different from other brain activations that may reflect task-specific strategic processing.