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For sentence comprehension, information carried by semantic relations between constituents must be combined with other information to decode the constituent structure of a sentence, due to atypical and noisy situations of language use. Neural correlates of decoding sentence structure by semantic information have remained largely unexplored. In this functional MRI study, we examine the neural basis of semantic-driven syntactic parsing during sentence reading and compare it with that of other types of syntactic parsing driven by word order and case marking. Chinese transitive sentences of various structures were investigated, differing in word order, case making, and agent-patient semantic relations (i.e., same vs. different in animacy). For the non-canonical unmarked sentences without usable case marking, a semantic-driven effect triggered by agent-patient ambiguity was found in the left inferior frontal gyrus opercularis (IFGoper) and left inferior parietal lobule, with the activity not being modulated by naturalness factors of the sentences. The comparison between each type of non-canonical sentences with canonical sentences revealed that the non-canonicity effect engaged the left posterior frontal and temporal regions, in line with previous studies. No extra neural activity was found responsive to case marking within the non-canonical sentences. A word order effect across all types of sentences was also found in the left IFGoper, suggesting a common neural substrate between different types of parsing. The semantic-driven effect was also observed for the non-canonical marked sentences but not for the canonical sentences, suggesting that semantic information is used in decoding sentence structure in addition to case marking. The current findings illustrate the neural correlates of syntactic parsing with semantics, and provide neural evidence of how semantics facilitates syntax together with other information.

Microstates represent electroencephalographic (EEG) activity as a sequence of switching, transient, metastable states. Growing evidence suggests the useful information on brain states is to be found in the higher-order temporal structure of these sequences. Instead of focusing on transition probabilities, here we propose “Microsynt”, a method designed to highlight higher-order interactions that form a preliminary step towards understanding the syntax of microstate sequences of any length and complexity. Microsynt extracts an optimal vocabulary of “words” based on the length and complexity of the full sequence of microstates. Words are then sorted into classes of entropy and their representativeness within each class is statistically compared with surrogate and theoretical vocabularies. We applied the method on EEG data previously collected from healthy subjects undergoing propofol anesthesia, and compared their “fully awake” (BASE) and “fully unconscious” (DEEP) conditions. Results show that microstate sequences, even at rest, are not random but tend to behave in a more predictable way, favoring simpler sub-sequences, or “words”. Contrary to high-entropy words, lowest-entropy binary microstate loops are prominent and favored on average 10 times more than what is theoretically expected. Progressing from BASE to DEEP, the representation of low-entropy words increases while that of high-entropy words decreases. During the awake state, sequences of microstates tend to be attracted towards “A – B – C” microstate hubs, and most prominently A – B binary loops. Conversely, with full unconsciousness, sequences of microstates are attracted towards “C – D – E” hubs, and most prominently C – E binary loops, confirming the putative relation of microstates A and B to externally-oriented cognitive processes and microstate C and E to internally-generated mental activity. Microsynt can form a syntactic signature of microstate sequences that can be used to reliably differentiate two or more conditions.

Intelligible communication with others as well as covert conscious thought requires us to combine a representation of the external world with inner abstract concepts.Interaction with the external world through sensory perception and motor execution is arranged as sequences in time and space, whereas abstract thought and invariant categories are independent of the moment. Using advanced MRI-based fibre tracking on high resolution data from 183 participants in the Human Connectome Project, we identified two large supramodal systems comprising specific cortical regions and their connecting fibre tracts; a dorsal one for processing of sequences in time and space, and a ventral one for concepts and categories. We found that two hub regions exist in the executive front and the perceptive back of the brain where these two cognitive processes converge, constituting a dual-loop model. The hubs are located in the onto- and phylogenetically youngest regions of the cortex. We propose that this hub feature serves as the neural substrate for the more abstract sense of syntax in humans, i.e. for the system populating sequences with content in all cognitive domains. The hubs bring together two separate systems (dorsal and ventral) at the front and the back of the brain and create a closed-loop. The closed-loop facilitates recursivity and forethought, which we use twice; namely, for communication with others about things that are not there and for covert thought.

• Word order, case markers, and semantics are combined to decode a sentence structure. • Semantic-driven parsing in unmarked non-canonical sentences activates Broca's area. • Different types of syntactic parsing recruit a common neural substrate. For sentence comprehension, information carried by semantic relations between constituents must be combined with other information to decode the constituent structure of a sentence, due to atypical and noisy situations of language use. Neural correlates of decoding sentence structure by semantic information have remained largely unexplored. In this functional MRI study, we examine the neural basis of semantic-driven syntactic parsing during sentence reading and compare it with that of other types of syntactic parsing driven by word order and case marking. Chinese transitive sentences of various structures were investigated, differing in word order, case making, and agent-patient semantic relations (i.e., same vs. different in animacy). For the non-canonical unmarked sentences without usable case marking, a semantic-driven effect triggered by agent-patient ambiguity was found in the left inferior frontal gyrus opercularis (IFGoper) and left inferior parietal lobule, with the activity not being modulated by naturalness factors of the sentences. The comparison between each type of non-canonical sentences with canonical sentences revealed that the non-canonicity effect engaged the left posterior frontal and temporal regions, in line with previous studies. No extra neural activity was found responsive to case marking within the non-canonical sentences. A word order effect across all types of sentences was also found in the left IFGoper, suggesting a common neural substrate between different types of parsing. The semantic-driven effect was also observed for the non-canonical marked sentences but not for the canonical sentences, suggesting that semantic information is used in decoding sentence structure in addition to case marking. The current findings illustrate the neural correlates of syntactic parsing with semantics, and provide neural evidence of how semantics facilitates syntax together with other information. [ABSTRACT FROM AUTHOR]

Theories of language organization in the brain commonly posit that different regions underlie distinct linguistic mechanisms. However, such theories have been criticized on the grounds that many neuroimaging studies of language processing find similar effects across regions. Moreover, condition by region interaction effects, which provide the strongest evidence of functional differentiation between regions, have rarely been offered in support of these theories. Here we address this by using lesion-symptom mapping in three large, partially-overlapping groups of aphasia patients with left hemisphere brain damage due to stroke (N = 121, N = 92, N = 218). We identified multiple measure by region interaction effects, associating damage to the posterior middle temporal gyrus with syntactic comprehension deficits, damage to posterior inferior frontal gyrus with expressive agrammatism, and damage to inferior angular gyrus with semantic category word fluency deficits. Our results are inconsistent with recent hypotheses that regions of the language network are undifferentiated with respect to high-level linguistic processing.

The present study examined the longitudinal relations of brain and behavior from ages 6–7.5 years old to test the bootstrapping account of language development. Prior work suggests that children's vocabulary development is foundational for acquiring grammar (e.g., semantic bootstrapping) and that children rely on the syntactic context of sentences to learn the meaning of new words (e.g., syntactic bootstrapping). Yet, little is known about the dynamics underlying semantic and syntactic development as children enter elementary school. In a series of preregistered and exploratory analyses, we tested how semantic and syntactic behavioral skills may influence the development of brain regions implicated in these processes, i.e. left posterior middle temporal gyrus (pMTG) and inferior frontal gyrus (pars opercularis, IFGop), respectively. Vice-a-versa, we tested how these brain regions may influence the development of children's semantic and syntactic behavioral skills. We assessed semantic (N = 26) and syntactic (N = 30) processes behaviorally and in the brain when children were ages 5.5–6.5 years old (Time 1) and again at 7–8 years old (Time 2). All brain-behavior analyses controlled for T1 autoregressive effects and phonological memory. Exploratory hierarchical regression analyses suggested bi-directional influences, but with greater support for syntactic bootstrapping. Across the analyses, there was a small to medium effect of change in variance in models where semantics predicted syntax. Conversely, there was medium to large change in variance in models where syntax predicted semantics. In line with prior literature, results suggest a close relationship between lexical and grammatical development in children ages 6–7.5 years old. However, there was more robust evidence for syntactic bootstrapping, suggesting that acquisition of phrase structure in school age children may allow for more effective learning of word meanings. This complements prior behavioral studies and suggests a potential shift in the early reliance on semantics to later reliance on syntax in development.

Functional neuroimaging and lesion-symptom mapping investigations implicate a left frontal–temporal–parietal network for sentence processing. The majority of studies have focused on sentence comprehension, with fewer in the domain of sentence production, which have not fully elucidated overlapping and/or unique brain structures associated with the two domains, particularly for sentences with noncanonical word order. Using voxel-based lesion symptom mapping (VLSM) we examined the relationship between lesions within the left hemisphere language network and both sentence comprehension and production of simple and complex syntactic structures in 76 participants with chronic stroke-induced aphasia. Results revealed shared regions across domains in the anterior and posterior superior temporal gyri (aSTG, pSTG), and the temporal pole (adjusted for verb production/comprehension). Additionally, comprehension was associated with lesions in the anterior and posterior middle temporal gyri (aMTG, pMTG), the MTG temporooccipital regions, SMG/AG, central and parietal operculum, and the insula. Subsequent VLSM analyses (production versus comprehension) revealed critical regions associated with each domain: anterior temporal lesions were associated with production; posterior temporo-parietal lesions were associated with comprehension, implicating important roles for regions within the ventral and dorsal stream processing routes, respectively. Processing of syntactically complex, noncanonical (adjusted for canonical), sentences was associated with damage to the pSTG across domains, with additional damage to the pMTG and IPL associated with impaired sentence comprehension, suggesting that the pSTG is crucial for computing noncanonical sentences across domains and that the pMTG, and IPL are necessary for re-analysis of thematic roles as required for resolution of long-distance dependencies. These findings converge with previous studies and extend our knowledge of the neural mechanisms of sentence comprehension to production, highlighting critical regions associated with both domains, and further address the mechanism engaged for syntactic computation, controlled for the contribution of verb processing.

The P600 Event-Related Brain Potential, elicited by syntactic violations in sentences, is generally interpreted as indicating language-specific structural/combinatorial processing, with far-reaching implications for models of language. P600 effects are also often taken as evidence for language-like grammars in non-linguistic domains like music or arithmetic. An alternative account, however, interprets the P600 as a P3, a domain-general brain response to salience. Using time-generalized multivariate pattern analysis, we demonstrate that P3 EEG patterns, elicited in a visual Oddball experiment, account for the P600 effect elicited in a syntactic violation experiment: P3 pattern-trained MVPA can classify P600 trials just as well as P600-trained ones. A second study replicates and generalizes this finding, and demonstrates its specificity by comparing it to face- and semantic mismatch-associated EEG responses. These results indicate that P3 and P600 share neural patterns to a substantial degree, calling into question the interpretation of P600 as a language-specific brain response and instead strengthening its association with the P3. More generally, our data indicate that observing P600-like brain responses provides no direct evidence for the presence of language-like grammars, in language or elsewhere. • There is an ongoing debate about the possible identity of P600 and P3. • We applied time-resolved MVPA decoding to Oddball and sentence processing EEG data. • A linear classifier was trained to detect patterns in P3 data and tested on P600 data. • The P3 classifiers successfully decoded the P600, but not other ERP components. • This indicates P600 effects are not syntax specific, but correspond to a generic P3. [ABSTRACT FROM AUTHOR]

When people communicate, they come to see the world in a similar way to each other by aligning their mental representations at such levels as syntax. Syntax is an essential feature of human language that distinguishes humans from other non-human animals. However, whether and how communicators share neural representations of syntax is not well understood. Here we addressed this issue by measuring the brain activity of both communicators in a series of dyadic communication contexts, by using functional near-infrared spectroscopy (fNIRS)-based hyperscanning. Two communicators alternatively spoke sentences either with the same or with different syntactic structures. Results showed a significantly higher-level increase of interpersonal neural synchronization (INS) at right posterior superior temporal cortex when communicators produced the same syntactic structures as each other compared to when they produced different syntactic structures. These increases of INS correlated significantly with communication quality. Our findings provide initial evidence for shared neural representations of syntax between communicators. • Shared neural representations of syntax were found during dyadic communication. • Neural synchronization underlay the shared representations of syntax. • Neural synchronization occurred bilaterally rather than on left hemisphere only. • Neural synchronization reflected effect of the prior syntactic context. • Neural synchronization significantly correlated with communication quality. [ABSTRACT FROM AUTHOR]

Abstract Language skills increase as the brain matures. Language processing, especially the comprehension of syntactically complex sentences, is supported by a brain network involving functional interactions between left inferior frontal and left temporal regions in the adult brain, with reduced functional interactions in children. Here, we examined the gray matter covariance of the cortical thickness network relevant for syntactic processing in relation to language abilities in preschool children (i.e., 5-year-olds) and analyzed the developmental changes of the cortical thickness covariance cross-sectionally by comparing preschool children, school age children, and adults. Further, to demonstrate the agreement of cortical thickness covariance and white matter connectivity, tractography analyses were performed. Covariance of language-relevant seeds in preschoolers was strongest in contralateral homologous regions. A more adult-like, significant cortical thickness covariance between left frontal and left temporal regions, however, was observed in preschoolers with advanced syntactic language abilities. By comparing the three age groups, we could show that the cortical thickness covariance pattern from the language-associated seeds develops progressively from restricted in preschoolers to widely-distributed brain regions in adults. In addition, our results suggest that the cortical thickness covariance difference of the left inferior frontal gyrus to superior temporal gyrus/sulcus between preschoolers and adults is accompanied by distinctions in the white matter tracts linking these two areas, with more mature white matter in the arcuate fasciculus in adults compared to preschoolers. These findings provide anatomical evidence for developmental changes in language both from the perspective of gray matter structure co-variation within the language network and white matter maturity as the anatomical substrate for the structural covariance. [ABSTRACT FROM AUTHOR]

Abstract Communication is an inferential process. In particular, language comprehension constantly requires top-down efforts, as often multiple interpretations are compatible with a given sentence. To assess top-down processing in the language domain, our experiment employed ambiguous sentences that allow for multiple interpretations (e.g., The client sued the murderer with the corrupt lawyer. , where the corrupt lawyer could either belong to The client or the murderer). Interpretation thus depended on whether participants chunk the words of the sentence into short or long syntactic phrases. In principle, bottom-up acoustic information (i.e., the presence or absence of an intonational phrase boundary at the offset of the murderer) indicates one of the two possible interpretations. Yet, acoustic information often indicates interpretations that require words to be chunked into overly long phrases that would overburden working memory. Processing is biased against these demands, reflected in a top-down preference to chunk words into short rather than long phrases. It is often proposed, but also hotly debated, that the ability to chunk words into short phrases is subserved by the left inferior frontal gyrus (IFG). Here, we employed focal repetitive transcranial magnetic stimulation to perturb the left IFG, which resulted in a further decrease of the aptitude to tolerate long phrases, indicating the inability of the left IFG to assist the chunking of words into phrases. In contrast, the processing of auditory information was not affected. Our findings support a causal top-down role of the left inferior frontal gyrus in the chunking of words into phrases. Highlights • Causal role of left IFG in syntactic phrase formation unclear. • TMS stimulation of left IFG disrupts ability to form long syntactic phrases. • Left IFG is causal in syntactic phrase formation. [ABSTRACT FROM AUTHOR]

• Microstate sequences are best studied considering high-order temporal characteristics. • We present a method, Microsynt, to study the syntax of microstate sequences. • Microstate sequences are not random but favor low entropy words with binary loops. • During consciousness, externally oriented microstate binary loops are prominent. • Internally generated binary loops become prominent during unconscious states. Microstates represent electroencephalographic (EEG) activity as a sequence of switching, transient, metastable states. Growing evidence suggests the useful information on brain states is to be found in the higher-order temporal structure of these sequences. Instead of focusing on transition probabilities, here we propose "Microsynt", a method designed to highlight higher-order interactions that form a preliminary step towards understanding the syntax of microstate sequences of any length and complexity. Microsynt extracts an optimal vocabulary of "words" based on the length and complexity of the full sequence of microstates. Words are then sorted into classes of entropy and their representativeness within each class is statistically compared with surrogate and theoretical vocabularies. We applied the method on EEG data previously collected from healthy subjects undergoing propofol anesthesia, and compared their "fully awake" (BASE) and "fully unconscious" (DEEP) conditions. Results show that microstate sequences, even at rest, are not random but tend to behave in a more predictable way, favoring simpler sub-sequences, or "words". Contrary to high-entropy words, lowest-entropy binary microstate loops are prominent and favored on average 10 times more than what is theoretically expected. Progressing from BASE to DEEP, the representation of low-entropy words increases while that of high-entropy words decreases. During the awake state, sequences of microstates tend to be attracted towards "A – B – C" microstate hubs, and most prominently A – B binary loops. Conversely, with full unconsciousness, sequences of microstates are attracted towards "C – D – E" hubs, and most prominently C – E binary loops, confirming the putative relation of microstates A and B to externally-oriented cognitive processes and microstate C and E to internally-generated mental activity. Microsynt can form a syntactic signature of microstate sequences that can be used to reliably differentiate two or more conditions. [ABSTRACT FROM AUTHOR]

Storage and reordering of incoming information are two core processes required for successful sentence comprehension. Storage is necessary whenever the verb and its arguments (i.e., subject and object) are separated over a long distance, while reordering is necessary whenever the argument order is atypical (e.g., object-first order in German, where subject-first order is typical). Previous neuroimaging work has associated storage with the left planum temporale (PT), and reordering with the left posterior inferior frontal gyrus (pIFG). Here, we tested the causal role of the PT and pIFG in storage and reordering using repetitive transcranial magnetic stimulation (rTMS). We applied either effective rTMS over PT or pIFG, or sham rTMS, while subjects listened to sentences that independently varied storage demands (short vs. long argument–verb distance) and reordering demands (subject– vs. object-first argument order). We found that rTMS over pIFG, but not PT, selectively affected reordering during the processing of sentences with a long argument–verb distance. Specifically, relative to sham rTMS, rTMS over pIFG significantly increased the performance difference between object– and subject-first long-distance sentences. These results demonstrate a causal involvement of left pIFG in reordering during sentence comprehension and thus contribute to a better understanding of the role of the pIFG in language processing. [ABSTRACT FROM AUTHOR]

The ability to predict upcoming structured events based on long-term knowledge and contextual priors is a fundamental principle of human cognition. Tonal music triggers predictive processes based on structural properties of harmony, i.e., regularities defining the arrangement of chords into well-formed musical sequences. While the neural architecture of structure-based predictions during music perception is well described, little is known about the neural networks for analogous predictions in musical actions and how they relate to auditory perception. To fill this gap, expert pianists were presented with harmonically congruent or incongruent chord progressions, either as musical actions (photos of a hand playing chords) that they were required to watch and imitate without sound, or in an auditory format that they listened to without playing. By combining task-based functional magnetic resonance imaging (fMRI) with functional connectivity at rest, we identified distinct sub-regions in right inferior frontal gyrus (rIFG) interconnected with parietal and temporal areas for processing action and audio sequences, respectively. We argue that the differential contribution of parietal and temporal areas is tied to motoric and auditory long-term representations of harmonic regularities that dynamically interact with computations in rIFG. Parsing of the structural dependencies in rIFG is co-determined by both stimulus- or task-demands. In line with contemporary models of prefrontal cortex organization and dual stream models of visual-spatial and auditory processing, we show that the processing of musical harmony is a network capacity with dissociated dorsal and ventral motor and auditory circuits, which both provide the infrastructure for predictive mechanisms optimising action and perception performance. [ABSTRACT FROM AUTHOR]

Intelligible communication with others as well as covert conscious thought requires us to combine a representation of the external world with inner abstract concepts. Interaction with the external world through sensory perception and motor execution is arranged as sequences in time and space, whereas abstract thought and invariant categories are independent of the moment. Using advanced MRI-based fibre tracking on high resolution data from 183 participants in the Human Connectome Project, we identified two large supramodal systems comprising specific cortical regions and their connecting fibre tracts; a dorsal one for processing of sequences in time and space, and a ventral one for concepts and categories. We found that two hub regions exist in the executive front and the perceptive back of the brain where these two cognitive processes converge, constituting a dual-loop model. The hubs are located in the onto- and phylogenetically youngest regions of the cortex. We propose that this hub feature serves as the neural substrate for the more abstract sense of syntax in humans, i.e. for the system populating sequences with content in all cognitive domains. The hubs bring together two separate systems (dorsal and ventral) at the front and the back of the brain and create a closed-loop. The closed-loop facilitates recursivity and forethought, which we use twice; namely, for communication with others about things that are not there and for covert thought. • The termination maps of two large tract systems parcellate the cerebral cortex. • The conjunction of dorsal and ventral cortical termination maps uncover two hub regions. • The closed-loop allows communication with others and internal thought. [Display omitted] [ABSTRACT FROM AUTHOR]

How is syntactic analysis implemented by the human brain during language comprehension? The current study combined methods from computational linguistics, eyetracking, and fMRI to address this question. Subjects read passages of text presented as paragraphs while their eye movements were recorded in an MRI scanner. We parsed the text using a probabilistic context-free grammar to isolate syntactic difficulty. Syntactic difficulty was quantified as syntactic surprisal, which is related to the expectedness of a given word's syntactic category given its preceding context. We compared words with high and low syntactic surprisal values that were equated for length, frequency, and lexical surprisal, and used fixation-related (FIRE) fMRI to measure neural activity associated with syntactic surprisal for each fixated word. We observed greater neural activity for high than low syntactic surprisal in two predicted cortical regions previously identified with syntax: left inferior frontal gyrus (IFG) and less robustly, left anterior superior temporal lobe (ATL). These results support the hypothesis that left IFG and ATL play a central role in syntactic analysis during language comprehension. More generally, the results suggest a broader cortical network associated with syntactic prediction that includes increased activity in bilateral IFG and insula, as well as fusiform and right lingual gyri. [ABSTRACT FROM AUTHOR]

Sentence comprehension requires the integration of both syntactic and semantic information, the acquisition of which seems to have different trajectories in the developing brain. Using functional magnetic resonance imaging, we examined the neural correlates underlying syntactic and semantic processing during auditory sentence comprehension as well as its development in preschool children by manipulating case marking and animacy hierarchy cues, respectively. A functional segregation was observed within Broca's area in the left inferior frontal gyrus for adults, where the pars opercularis was involved in syntactic processing and the pars triangularis in semantic processing. By contrast, five-year-old children sensitive to animacy hierarchy cues showed diffuse activation for semantic processing in the left inferior frontal and posterior temporal cortices. While no main effect of case marking was found in the left fronto-temporal language network, children with better syntactic skills showed greater neural responses for syntactically complex sentences, most prominently in the posterior superior temporal cortex. The current study provides both behavioral and neural evidence that five-year-old children compared to adults rely more on semantic information than on syntactic cues during sentence comprehension, but with the development of syntactic abilities, their brain activation in the left fronto-temporal network increases for syntactic processing. [ABSTRACT FROM AUTHOR]

The neuronal processes underlying dance observation have been the focus of an increasing number of brain imaging studies over the past decade. However, the existing literature mainly dealt with effects of motor and visual expertise, whereas the neural and cognitive mechanisms that underlie the interpretation of dance choreographies remained unexplored. Hence, much attention has been given to the action observation network (AON) whereas the role of other potentially relevant neuro-cognitive mechanisms such as mentalizing (theory of mind) or language (narrative comprehension) in dance understanding is yet to be elucidated. We report the results of an fMRI study where the structural coherence of short contemporary dance choreographies was manipulated parametrically using the same taped movement material. Our participants were all trained dancers. The whole-brain analysis argues that the interpretation of structurally coherent dance phrases involves a subpart (superior parietal) of the AON as well as mentalizing regions in the dorsomedial prefrontal cortex. An ROI analysis based on a similar study using linguistic materials ( Pallier et al., 2011 ) suggests that structural processing in language and dance might share certain neural mechanisms. [ABSTRACT FROM AUTHOR]

To advance understanding of brain networks involved in language, the effective connectivity between 26 cortical regions implicated in language by a community analysis and 360 cortical regions was measured in 171 humans from the Human Connectome Project, and complemented with functional connectivity and diffusion tractography, all using the HCP multimodal parcellation atlas. A (semantic) network (Group 1) involving inferior cortical regions of the superior temporal sulcus cortex (STS) with the adjacent inferior temporal visual cortex TE1a and temporal pole TG, and the connected parietal PGi region, has effective connectivity with inferior temporal visual cortex (TE) regions; with parietal PFm which also has visual connectivity; with posterior cingulate cortex memory-related regions; with the frontal pole, orbitofrontal cortex, and medial prefrontal cortex; with the dorsolateral prefrontal cortex; and with 44 and 45 for output regions. It is proposed that this system can build in its temporal lobe (STS and TG) and parietal parts (PGi and PGs) semantic representations of objects incorporating especially their visual and reward properties. Another (semantic) network (Group 3) involving superior regions of the superior temporal sulcus cortex and more superior temporal lobe regions including STGa, auditory A5, TPOJ1, the STV and the Peri-Sylvian Language area (PSL) has effective connectivity with auditory areas (A1, A4, A5, Pbelt); with relatively early visual areas involved in motion, e.g., MT and MST, and faces/words (FFC); with somatosensory regions (frontal opercular FOP, insula and parietal PF); with other TPOJ regions; and with the inferior frontal gyrus regions (IFJa and IFSp). It is proposed that this system builds semantic representations specialising in auditory and related facial motion information useful in theory of mind and somatosensory / body image information, with outputs directed not only to regions 44 and 45, but also to premotor 55b and midcingulate premotor cortex. Both semantic networks (Groups 1 and 3) have access to the hippocampal episodic memory system via parahippocampal TF. A third largely frontal network (Group 2) (44, 45, 47l; 55b; the Superior Frontal Language region SFL; and including temporal pole TGv) receives effective connectivity from the two semantic systems, and is implicated in syntax and speech output. [ABSTRACT FROM AUTHOR]

Broca's area is proposed as a crucial brain area for linguistic computations. Language processing goes beyond word-level processing, also implying the integration of meaningful information (semantics) with the underlying structural skeleton (syntax). There is an on-going debate about the specialisation of the subregions of Broca's area—Brodmann areas (BA) 44 and 45—regarding the latter aspects. Here, we tested if syntactic information is specifically processed in BA 44, whereas BA 45 is mainly recruited for semantic processing. We contrasted conditions with sentence structure against conditions with random order in two fMRI experiments. Besides, in order to disentangle these processes, we systematically removed the amount of semantic information available in the stimuli. This was achieved in Experiment 1 by replacing meaningful words (content words) by pseudowords. Within real word conditions we found broad activation in the left hemisphere, including the inferior frontal gyrus (BA 44/45/47), the anterior temporal lobe and posterior superior temporal gyrus (pSTG) and sulcus (pSTS). For pseudowords we found a similar activation pattern, still involving BA 45. Among the pseudowords in Experiment 1, we kept those word elements that convey meaning like un - in un happy or - hood in brother hood (i.e. derivational morphology). In Experiment 2 we tested whether the activation in BA 45 was due to their presence. We therefore further removed derivational morphology, only leaving word elements that determine syntactic structure (i.e. inflectional morphology, e.g. the verb ending - s in he paint s ). Now, in the absence of all semantic cues, including derivational morphology, only BA 44 was active. Additional analyses showed a selective responsiveness of this area to syntax-relevant cues. These findings confirm BA 44 as a core area for the processing of pure syntactic information. This furthermore suggests that the brain represents structural and meaningful aspects of language separately. [ABSTRACT FROM AUTHOR]

Syntactically and semantically anomalous words encountered during sentence comprehension are known to elicit dissociable electrophysiological responses, which are thought to reflect distinct aspects of language processing. However, the sources of these responses have not been well characterized. We used beamforming analysis of magnetoencephalography (MEG) data to map generators of electrophysiological responses to linguistic anomalies. Anomalous words occurred in the context of a sentence acceptability judgement task conducted in both visual and auditory modalities. Time–frequency analysis revealed that both kinds of violations elicited event-related synchronization (ERS) in the delta–theta frequency range (1–5 Hz), and desynchronization (ERD) in the alpha–beta range (8–30 Hz). In addition, these responses were differentially modulated by violation type and presentation modality. 1–5 Hz responses were consistently localized within medial prefrontal cortex and did not vary significantly across violation types, but were stronger for visual presentation. In contrast, 8–30 Hz ERD occurred in different regions for different violation types. For semantic violations the distribution was predominantly in the bilateral occipital cortex and left temporal and inferior frontal regions, and these effects did not differ for visual and auditory presentation. In contrast, syntactic responses were strongly affected by presentation modality. Under visual presentation, syntactic violations elicited bilateral 8–30 Hz ERD extending into dorsal parietal and frontal regions, whereas effects were much weaker and mostly statistically insignificant in the auditory modality. These results suggest that delta–theta ERS reflects generalized increases in working memory demands related to linguistic anomaly detection, while alpha–beta ERD reflects specific activation of cortical regions involved in distinct aspects of linguistic processing, such as semantic vs. phonological short-term memory. Beamforming analysis of time-domain average signals (ERFs) revealed an N400m effect for semantic anomalies in both modalities, localized to left superior temporal and posterior frontal regions, and a later P600-like effect for syntactic anomalies in both modalities, widespread over bilateral frontal, posterior temporal, and parietal regions. These results indicate that time-domain averaged responses and induced oscillatory responses have distinct properties, including localization and modality dependence, and likely reflect dissociable and complementary aspects of neural activity related to language comprehension and additional task-related processes. [ABSTRACT FROM AUTHOR]

Theories of language organization in the brain commonly posit that different regions underlie distinct linguistic mechanisms. However, such theories have been criticized on the grounds that many neuroimaging studies of language processing find similar effects across regions. Moreover, condition by region interaction effects, which provide the strongest evidence of functional differentiation between regions, have rarely been offered in support of these theories. Here we address this by using lesion-symptom mapping in three large, partially-overlapping groups of aphasia patients with left hemisphere brain damage due to stroke (N = 121, N = 92, N = 218). We identified multiple measure by region interaction effects, associating damage to the posterior middle temporal gyrus with syntactic comprehension deficits, damage to posterior inferior frontal gyrus with expressive agrammatism, and damage to inferior angular gyrus with semantic category word fluency deficits. Our results are inconsistent with recent hypotheses that regions of the language network are undifferentiated with respect to high-level linguistic processing. [ABSTRACT FROM AUTHOR]

Abstract: Despite general agreement on shared syntactic resources in music and language, the neuroanatomical underpinnings of this overlap remain largely unexplored. While previous studies mainly considered frontal areas as supramodal grammar processors, the domain-general syntactic role of temporal areas has been so far neglected. Here we capitalized on the excellent spatial and temporal resolution of subdural EEG recordings to co-localize low-level syntactic processes in music and language in the temporal lobe in a within-subject design. We used Brain Surface Current Density mapping to localize and compare neural generators of the early negativities evoked by violations of phrase structure grammar in both music and spoken language. The results show that the processing of syntactic violations relies in both domains on bilateral temporo-fronto-parietal neural networks. We found considerable overlap of these networks in the superior temporal lobe, but also differences in the hemispheric timing and relative weighting of their fronto-temporal constituents. While alluding to the dissimilarity in how shared neural resources may be configured depending on the musical or linguistic nature of the perceived stimulus, the combined data lend support for a co-localization of early musical and linguistic syntax processing in the temporal lobe. [Copyright &y& Elsevier]

Abstract: Children''s language skills develop rapidly with increasing age, and several studies indicate that they use language- and age-specific strategies to understand complex sentences. In the present experiment, functional magnetic resonance imaging (fMRI) and behavioral measures were used to investigate the acquisition of case-marking cues for sentence interpretation in the developing brain of German preschool children with a mean age of 6years. Short sentences were presented auditorily, consisting of a transitive verb and two case-marked arguments with canonical subject-initial or non canonical object-initial word order. Overall group results revealed mainly left hemispheric activation in the perisylvian cortex with increased activation in the inferior parietal cortex (IPC), and the anterior cingulate cortex (ACC) for object-initial compared to subject-initial sentences. However, single‐subject analysis suggested two distinct activation patterns within the group which allowed a classification into two subgroups. One subgroup showed the predicted activation increase in the left inferior frontal gyrus (IFG) for the more difficult object-initial compared to subject-initial sentences, while the other group showed the reverse effect. This activation in the left IFG can be taken to reflect the degree to which adult-like sentence processing strategies, necessary to integrate case-marking information, are applied. Additional behavioral data on language development tests show that these two subgroups differ in their grammatical knowledge. Together with these behavioral findings, the results indicate that the use of a particular processing strategy is not dependent on age as such, but rather on the child''s individual grammatical knowledge and the ability to use specific language cues for successful sentence comprehension. [Copyright &y& Elsevier]

Abstract: Written mathematical notation conveys, in a compact visual form, the nested functional relations among abstract concepts such as operators, numbers or sets. Is the comprehension of mathematical expressions derived from the human capacity for processing the recursive structure of language? Or does algebraic processing rely only on a language-independent network, jointly involving the visual system for parsing the string of mathematical symbols and the intraparietal system for representing numbers and operators? We tested these competing hypotheses by scanning mathematically trained adults while they viewed simple strings ranging from randomly arranged characters to mathematical expressions with up to three levels of nested parentheses. Syntactic effects were observed in behavior and in brain activation measured with functional magnetic resonance imaging (fMRI) and magneto-encephalography (MEG). Bilateral occipito-temporal cortices and right parietal and precentral cortices appeared as the primary nodes for mathematical syntax. MEG estimated that a mathematical expression could be parsed by posterior visual regions in less than 180ms. Nevertheless, a small increase in activation with increasing expression complexity was observed in linguistic regions of interest, including the left inferior frontal gyrus and the posterior superior temporal sulcus. We suggest that mathematical syntax, although arising historically from language competence, becomes “compiled” into visuo-spatial areas in well-trained mathematics students. [Copyright &y& Elsevier]

Abstract: This is a highly selective review of functional imaging papers, which have attempted to isolate the neural substrates of semantic and syntactic processing in the human brain. The main emphasis is historical, with a special consideration of the mutual relationship between the traditional, lesion-based approach to the neurology of language and the contributions of the tremendous development of imaging techniques of the last decades. [Copyright &y& Elsevier]

Abstract: This study used fMRI to inform a debate between two theories concerning the representation of reflexive verbs. Reflexives are verbs that denote an action that the subject applies on herself (e.g., The woman stretched). These verbs are derived by a lexical operation that creates a reflexive from its transitive counterpart. Theories differ with respect to which thematic role is reduced by the lexical operation: the agent or the theme, and, consequently, whether the construction of sentences with reflexives in subject–verb order includes movement of the object to the subject position. To test this, we compared reflexive verbs with unaccusative verbs (e.g., The woman fell), and with unergative verbs (e.g., The woman jumped). Unaccusatives are derived by reduction of the role of the agent, and thus SV sentences with unaccusatives include movement to subject position. Unergatives do not undergo lexical operations and do not involve movement in SV sentences. The reflexives behaved like unergatives, and differently from unaccusatives: the activation pattern of unaccusatives compared with reflexives showed similar cortical pattern to that of unaccusatives compared with unergatives, with activations in the left inferior frontal gyrus and the left middle temporal gyrus (MTG). Comparing reflexives and unergatives revealed activation in the right MTG. These results indicate that reflexives differ from unaccusatives in their derivation. That is, reflexives do not involve the reduction of the agent of the parallel transitive, and hence no syntactic movement is involved in sentences in which the subject precedes the reflexive verb. [Copyright &y& Elsevier]

Abstract: Under real-life adverse listening conditions, the interdependence of the brain''s analysis of language structure (syntax) and its analysis of the acoustic signal is unclear. In two fMRI experiments, we first tested the functional neural organization when listening to increasingly complex syntax in fMRI. We then tested parametric combinations of syntactic complexity (argument scrambling in three degrees) with speech signal degradation (noise-band vocoding in three different numbers of bands), to shed light on the mutual dependency of sound and syntax analysis along the neural processing pathways. The left anterior and the posterior superior temporal sulcus (STS) as well as the left inferior frontal cortex (IFG) were linearly more activated as syntactic complexity increased (Experiment 1). In Experiment 2, when syntactic complexity was combined with improving signal quality, this pattern was replicated. However, when syntactic complexity was additive to degrading signal quality, the syntactic complexity effect in the IFG shifted dorsally and medially, and the activation effect in the left posterior STS shifted from posterior toward more middle sections of the sulcus. A distribution analysis of supra- as well as subthreshold data was indicative of this pattern of shifts in the anterior and posterior STS and within the IFG. Results suggest a signal quality gradient within the fronto-temporal language network. More signal-bound processing areas, lower in the processing hierarchy, become relatively more recruited for the analysis of complex language input under more challenging acoustic conditions (“upstream delegation”). This finding provides evidence for dynamic resource assignments along the neural pathways in auditory language comprehension. [Copyright &y& Elsevier]

Abstract: Sentences with embedding are more complex than sentences without embedding, because they contain more syntactic layers in their phrasal architecture. Until now, neuroimaging studies tested embedded sentences that also included syntactic movement. To explore which cortical areas are specifically involved in the processing of syntactic layers, we used embedded sentences that did not include syntactic movement. We compared sentences in which the verb was complemented with an embedded sentence (CP complement) to sentences with noun phrase (NP) complements. The comparison of sentences with and without embedding revealed activations in the left IFG, bilateral temporo-parietal cortices, bilateral MTG, and precuneus. We further examined the effect of embedding at the lexical level. For this, we tested whether verbs that can select CP complements, namely, whose lexical entry includes a CP option, are more complex than verbs that do not select CP complements, even when both verb types appeared in sentences without embedding. The comparison of verbs that can take CP complements with verbs that can take NP complements, when these verbs appeared with prepositional phrase complements, revealed activations in bilateral anterior MTG and precuneus, showing that embedding also affects processing at the lexical level. The results thus show that sentential embedding, even without syntactic movement, loads onto several cortical resources including the left IFG, indicating that the generation of syntactic layers is cognitively costly, and that embedding affects processing at both the sentence and the lexical levels. [Copyright &y& Elsevier]

Abstract: Humans differ substantially in their ability to implicitly extract structural regularities from experience, as required for learning the grammar of a language. The mechanisms underlying this fundamental inter-individual difference, which may determine initial success in language learning, are incompletely understood. Here, we use diffusion tensor magnetic resonance imaging (DTI) to determine white matter integrity around Broca''s area, which is crucially involved in both natural and artificial language processing. Twelve young, right-handed individuals completed an artificial grammar learning task, and DTI of their brains were acquired. Inter-individual variability in performance correlated with white matter integrity (increasing fractional anisotropy (FA)) in fibres arising from Broca''s area (left BA 44/45), but not from its right-hemispheric homologue. Variability in performance based on superficial familiarity did not show this association. Moreover, when Broca''s area was used as a seed mask for probabilistic tractography, we found that mean FA values within the generated tracts was higher in subjects with better grammar learning. Our findings provide the first evidence that integrity of white matter fibre tracts arising from Broca''s area is intimately linked with the ability to extract grammatical rules. The relevance of these findings for acquisition of a natural language has to be established in future studies. [Copyright &y& Elsevier]

Abstract: Neuroimaging studies of language processing have shown that different circuits within the language network are isolated by syntactic and semantic tasks. We examined differential activation in an fMRI study of language when a single task with two minimally distinct conditions is employed. 16 subjects participated in a Noun Phrase Formation Task that encompassed a minimal difference between syntactic and semantic conditions. In-magnet accuracy and response times were compared, imaging data were evaluated for effects of task conditions, and the functional connectivity between areas of differential response to conditions were evaluated using cross-subject, interregional correlations between measures of BOLD activity. Although no difference in performance was observed between conditions, random effects analysis pinpointed pivotal components of the syntactic and semantic circuits (p <0.01 corrected for multiple comparisons) usually isolated with more complex, sentence-level stimuli. These included bilateral Broca''s area and left inferior parietal lobe in the syntactic condition and left BA47 and left middle temporal gyrus in the semantic. Correlations among these regions did not pattern straightforwardly with the two task conditions, contrary to our expectations. Two significantly correlated circuits were identified (p <0.01): the well-documented connection between the left inferior parietal lobe and Broca''s area and a connection between the medial frontal lobe and BA 47. An intriguing pattern was revealed in how the two sets of regions correlated with three areas of significantly differential deactivation to task, areas that are co-extensive with the Default Network. The deactivating regions, plus those areas that inversely correlated with them, formed one coordinated sub-circuit, encompassing the regions identified with syntax. Areas that positively correlated with the deactivating regions encompassed the semantic circuit. We suggest that by leveraging the Default Network, a partial bifurcation in connectivity was obtained that appeared to be conditioned externally. These regions could be viewed as an interface, balancing activation between the two overlapping, condition-dependent sub-circuits to enhance differential brain response within a complex cognitive network. [Copyright &y& Elsevier]

Abstract: The importance of abstract syntactic structures and their crucial role in analyzing sentences have long been emphasized in contemporary linguistics, whereas the linear order model, in which next-coming words in a sentence are claimed to be predictable based on lexico-semantic association or statistics alone, has also been proposed and widely assumed. We examined these possibilities with magnetoencephalography (MEG) and measured cortical responses to a verb with either object–verb (OV) or subject–verb (SV) sentence structures, which were tested in a minimal-pair paradigm to compare syntactic and semantic decision tasks. Significant responses to the normal OV sentences were found in the triangular part of the left inferior frontal gyrus (F3t) at 120–140 ms from the verb onset, which were selective for explicit syntactic processing. The earliest left F3t responses can thus be regarded as predictive effects for the syntactic information of the next-coming verb, which cannot be explained by associative memory or statistical factors. Moreover, subsequent responses in the left insula at 150–170 ms were selective for the processing of the OV sentence structure. On the other hand, responses in the left mediofrontal and inferior parietal regions at 240–280 ms were related to syntactic anomaly and verb transitivity, respectively. These results revealed the dynamics of the multiple cortical regions that work in concert to analyze hierarchical syntactic structures and task-related information, further elucidating the top-down syntactic processing that is crucial during on-line sentence processing. [Copyright &y& Elsevier]

• We assessed longitudinal bi-directional relations of semantics and syntax • Semantics skill had a small to medium effect on neural basis of syntax • Syntax skill had a medium to large effect on neural basis of semantics • Results show greater evidence for syntactic bootstrapping in school-aged children • Study is the first neurocognitive demonstration of bootstrapping in language The present study examined the longitudinal relations of brain and behavior from ages 6–7.5 years old to test the bootstrapping account of language development. Prior work suggests that children's vocabulary development is foundational for acquiring grammar (e.g., semantic bootstrapping) and that children rely on the syntactic context of sentences to learn the meaning of new words (e.g., syntactic bootstrapping). Yet, little is known about the dynamics underlying semantic and syntactic development as children enter elementary school. In a series of preregistered and exploratory analyses, we tested how semantic and syntactic behavioral skills may influence the development of brain regions implicated in these processes, i.e. left posterior middle temporal gyrus (pMTG) and inferior frontal gyrus (pars opercularis, IFGop), respectively. Vice-a-versa, we tested how these brain regions may influence the development of children's semantic and syntactic behavioral skills. We assessed semantic (N = 26) and syntactic (N = 30) processes behaviorally and in the brain when children were ages 5.5–6.5 years old (Time 1) and again at 7–8 years old (Time 2). All brain-behavior analyses controlled for T1 autoregressive effects and phonological memory. Exploratory hierarchical regression analyses suggested bi-directional influences, but with greater support for syntactic bootstrapping. Across the analyses, there was a small to medium effect of change in variance in models where semantics predicted syntax. Conversely, there was medium to large change in variance in models where syntax predicted semantics. In line with prior literature, results suggest a close relationship between lexical and grammatical development in children ages 6–7.5 years old. However, there was more robust evidence for syntactic bootstrapping, suggesting that acquisition of phrase structure in school age children may allow for more effective learning of word meanings. This complements prior behavioral studies and suggests a potential shift in the early reliance on semantics to later reliance on syntax in development. [ABSTRACT FROM AUTHOR]

Functional magnetic resonance imaging (fMRI) in humans has revealed increases in brain activity associated with various mental activities that are task-dependent. However, changes in brain activity have been dependent on baseline as well as experimental tasks. In the present study, fMRI was applied to investigate the most appropriate baseline task, picture naming or passive viewing of nonsense objects, to isolate syntactic processes related to 14.7-s blocks of silent sentence generation in 10 neurologically normal adults. The aim of this comparison was to determine the most suitable baseline task for the purpose of elucidating changes in the neural substrates of sentence generation following therapy for syntax production problems. Use of naming but not passive object viewing as a baseline task obscured activity in Broca''s area, a region previously shown to be involved in syntactic processing. These results suggest that passive viewing of nonsense objects serves as a more appropriate baseline comparison than object naming for investigating sentence processing. [Copyright &y& Elsevier]

We present the results of correlation analyses for identifying temporally correlated activations between multiple regions of interest. We focused on functional connectivity for two regions in the prefrontal cortex: the left inferior frontal gyrus (L. F3t/F3O) and the left precentral sulcus (L. PrCS). Temporal correlations of functional magnetic resonance imaging signals were separately examined during a sentence comprehension task and a lexical decision task, thereby averaging data throughout all voxels within a region of interest used as a reference region. We found that the reciprocal connectivity between L. F3t/F3O and L. PrCS was significantly enhanced during sentence processing, but not during lexico-semantic processing, which was confirmed under both auditory and visual conditions. Furthermore, significantly correlated regions were mostly concentrated in the left prefrontal cortex during the sentence task. These results demonstrate that the functional connectivity within the left prefrontal cortex is selectively enhanced for processing sentences, which may subserve the use of syntactic information for integrating lexico-semantic information. [Copyright &y& Elsevier]

Recent data from lesion and brain imaging studies have questioned the well-established assumption of a close functional–anatomic link between syntax and Broca''s area and semantics and Wernicke''s area. In the present study we used functional magnetic resonance imaging (fMRI) to investigate the neuroanatomical correlates of semantic and syntactic functions and possible interdependencies between the related brain systems. In a completely crossed design we varied syntactic processing demands (easy vs difficult to process word order sequences) and the meaningfulness of sentences (real- vs pseudo-word sentences). In comparison to a backward speech condition we found an activation of the left perisylvian region, including the left inferior frontal cortex and the left superior and middle temporal gyri. Semantic in contrast to pseudo-word sentences elicited a stronger activation in both the anterior and the posterior perisylvian cortex. Syntactic difficulty had its strongest effect within the left inferior frontal region and this effect was more pronounced for semantic than nonsemantic speech. These results suggest that semantic and syntactic language functions are mediated by partly specialized brain systems but that there nevertheless exists a substantial functional overlap of the involved brain structures. [Copyright &y& Elsevier]

Functional neuroimaging and lesion-symptom mapping investigations implicate a left frontal–temporal–parietal network for sentence processing. The majority of studies have focused on sentence comprehension, with fewer in the domain of sentence production, which have not fully elucidated overlapping and/or unique brain structures associated with the two domains, particularly for sentences with noncanonical word order. Using voxel-based lesion symptom mapping (VLSM) we examined the relationship between lesions within the left hemisphere language network and both sentence comprehension and production of simple and complex syntactic structures in 76 participants with chronic stroke-induced aphasia. Results revealed shared regions across domains in the anterior and posterior superior temporal gyri (aSTG, pSTG), and the temporal pole (adjusted for verb production/comprehension). Additionally, comprehension was associated with lesions in the anterior and posterior middle temporal gyri (aMTG, pMTG), the MTG temporooccipital regions, SMG/AG, central and parietal operculum, and the insula. Subsequent VLSM analyses (production versus comprehension) revealed critical regions associated with each domain: anterior temporal lesions were associated with production; posterior temporo-parietal lesions were associated with comprehension, implicating important roles for regions within the ventral and dorsal stream processing routes, respectively. Processing of syntactically complex, noncanonical (adjusted for canonical), sentences was associated with damage to the pSTG across domains, with additional damage to the pMTG and IPL associated with impaired sentence comprehension, suggesting that the pSTG is crucial for computing noncanonical sentences across domains and that the pMTG, and IPL are necessary for re-analysis of thematic roles as required for resolution of long-distance dependencies. These findings converge with previous studies and extend our knowledge of the neural mechanisms of sentence comprehension to production, highlighting critical regions associated with both domains, and further address the mechanism engaged for syntactic computation, controlled for the contribution of verb processing. [ABSTRACT FROM AUTHOR]