Neuronal interactions between mentalising and action systems during indirect request processing

The spontaneous activities of the multiple demand network are related to individual differences in indirect replies comprehension

This study aims to investigate the brain networks engaged in the comprehension of indirect language, as well as the individual difference in this capacity. Specially, we aim to determine whether the difference is solely influenced by the difference in individuals' default network (DN)/language network or whether it also relies on the networks associated with processing of complex cognitive tasks, particularly the multiple demand network (MDN). Conversational indirectness scale (CIS) scores in the interpretation dimension were used as a behavioral indicator of the indirect comprehension tendency. Reading time difference between indirect replies and direct replies collected through a self-paced reading experiment was deemed as a behavioral indicator of comprehension speed of indirect replies comprehension. The two behavioral indicators were combined with resting-state functional magnetic resonance imaging (rs-fMRI). The behaviour-rfMRI analysis showed that ALFF value of right SPL and the functional connectivity (FC) between the right SPL and right IPL/SMA/ITG/Precuneus/bilateral IFG were positively correlated with the interpretation dimension of CIS scores. In addition, the ALFF value of right fusiform gyrus, the FC between the right fusiform gyrus and right precuneus, and the FCs between right SPL and right IPL/Precuneus/IFG were negatively correlated with indirect replies comprehension speed. Overlapping of these regions with large-scale brain network revealed that the right SPL was mainly located in the MDN, and the right fusiform gyrus was mainly located in the language network. Additionally, the areas showing functional connectivity with these regions were primarily located in the MDN, with a smaller subset located in the DN. Our findings suggest that the ability of individuals to actively and rapidly acquire indirect meaning relies not only on the support of the DN and the language network, but also requires collective support from the MDN.

Exploring Cognitive-Pragmatic Heterogeneity Following Acquired Brain Injury: A Cluster Analysis of Hint Comprehension

PURPOSE

Difficulties understanding nonliteral language (especially hints) are frequently reported following acquired brain injury (ABI). Several cognitive mechanisms, such as context processing, executive functions, and theory of mind (ToM), may underlie these disorders. However, their role remains controversial, mainly because of the characteristic heterogeneity of this population. Therefore, our study aimed to identify cognitive-pragmatic profiles in individuals with ABI.

METHOD

A new task of hint comprehension, manipulating executive demand, markers of hints, and ToM and neuropsychological tests were administered to 33 participants with frontal ABI and 33 control participants. Cluster analysis, a method sensitive to profile heterogeneity, was applied and coupled with error analysis.

RESULTS

We highlighted two cognitive-pragmatic profiles. One subgroup of participants with ABI exhibited contextual insensitivity, leading them to infer the utterance meaning based on linguistic decoding alone-literal meaning. This difficulty in understanding hints was associated with deficits in working memory, inhibition, and ToM. The second subgroup of participants with ABI showed difficulty with literal statements, associated with impaired inhibition and ToM. In addition, the two subgroups differed only on the ToM task. This result suggests that various types of ToM deficit (misunderstanding vs. incorrect attribution of mental states) could contribute to the variability of the pragmatic profiles observed (difficulties in interpreting hints vs. literal statements).

CONCLUSION

The experimental design adopted in this study provides valuable insight into the explanatory hypotheses of nonliteral language comprehension disorders and has important clinical implications.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.24069516.

Does the right temporo-parietal junction play a role in processing indirect speech acts? A transcranial magnetic stimulation study

In communication, much information is conveyed not explicitly but rather covertly, based on shared assumptions and common knowledge. For instance, when asked "Did you bring your cat to the vet?" a person could reply "It got hurt jumping down the table", thereby implicating that, indeed, the cat was brought to the vet. The assumption that getting hurt jumping down a table motivates a vet visit is tacitly attributed to the speaker by the listener, which implies Theory of Mind (ToM) processes. In the present study, we apply repetitive transcranial magnetic stimulation to the right temporo-parietal junction (rTPJ), a key brain region underlying ToM, with the aim to disrupt ToM processes necessary for language understanding. We then assess effects on the comprehension of indirect speech acts and their matched direct controls. In one set of conditions, the direct and indirect stimuli where not matched for speech act type, whereas, in the other, these were matched, therefore providing an unconfounded test case for in/directness. When indirect speech acts and direct controls were matched for speech act type (both statements), the indirect ones took longer to process both following sham and verum TMS. However, when the indirect and direct speech acts were not matched for communicative function (accept/decline offer vs. descriptive statement respectively), then a delay was detected for the indirect ones following sham TMS but, crucially, not following verum TMS. Additionally, TMS affected behavior in a ToM task. We therefore do not find evidence that the rTPJ is causally involved in comprehending of indirectness per se, but conclude that it could be involved instead in the processing of specific social communicative activity of rejecting of accepting offers, or to a combination of differing in/directness and communicative function. Our findings are consistent with the view that ToM processing in rTPJ is more important and/or more pronounced for offer acceptance/rejection than for descriptive answers.

The neurobiological map of theory of mind and pragmatic communication in autism

Children with autism often have difficulty with Theory of Mind (ToM), the ability to infer mental states, and pragmatic skills, the contextual use of language. Neuroimaging research suggests ToM and pragmatic skills overlap, as the ability to understand another's mental state is a prerequisite to interpersonal communication. To our knowledge, no study in the last decade has examined this overlap further. To assess the emerging consensus across neuroimaging studies of ToM and pragmatic skills in autism, we used coordinate-based activation likelihood estimation (ALE) analysis of 35 functional magnetic resonance imaging (MRI) studies (13 pragmatic skills, 22 ToM), resulting in a meta-analysis of 1,295 participants (647 autistic, 648 non-autistic) aged 7 to 49 years. Group difference analysis revealed decreased left inferior frontal gyrus (LIFG) activation in autistic participants during pragmatic skills tasks. For ToM tasks, we found reduced anterior cingulate cortex (ACC), medial prefrontal cortex (MPFC), and temporoparietal junction (TPJ) activation in autistic participants. Collectively, both ToM and pragmatic tasks showed activation in IFG and superior temporal gyrus (STG) and a reduction in left hemispheric activation in autistic participants. Overall, the findings underscore the cognitive and neural processing similarities between ToM and pragmatic skills, and their underlying neurobiological differences in autism.

Individual Differences in Emotion Attenuation Brought by Indirect Replies Is Related to Resting-State Brain Activity

During daily conversations, people prefer indirect replies in face-threatening situations. Existent studies have indicated that recipients tend to perceive the information conveyed by indirect replies as negative and emotion regions are engaged in indirect replies processing in face-threatening situations. In this study, we examined whether indirect replies can reduce recipients' experience of negative emotion and what are the underlying cerebral structures that may give rise to individual differences in the effectiveness of such replies in attenuating negative emotion. Behavior ratings and resting-stating functional magnetic resonance imaging (rs-fMRI) techniques were combined to explore these questions. We created dialogues expressing refusal or negative opinion with direct/indirect replies. Participants were asked to rate their emotional valence and arousal when they received such replies. The rating scores were used to correlate with spontaneous brain activity. Results showed that indirect replies indeed attenuated recipients' negative emotion experience. Moreover, the left caudate, the right anterior cingulate cortex (rACC), and the connectivity of rACC and left medial prefrontal cortex (lmPFC) were found to be positively correlated to individual differences in such emotion attenuation. Our findings provide direct empirical evidence for the face-saving function of indirect replies and reveal that the intrinsic brain activities of emotion network and theory of mind (ToM) network are related to individual differences in such emotion attenuation.

Non-literal language processing is jointly supported by the language and theory of mind networks: Evidence from a novel meta-analytic fMRI approach

Going beyond the literal meaning of language is key to communicative success. However, the mechanisms that support non-literal inferences remain debated. Using a novel meta-analytic approach, we evaluate the contribution of linguistic, social-cognitive, and executive mechanisms to non-literal interpretation. We identified 74 fMRI experiments (n = 1,430 participants) from 2001 to 2021 that contrasted non-literal language comprehension with a literal control condition, spanning ten phenomena (e.g., metaphor, irony, indirect speech). Applying the activation likelihood estimation approach to the 825 activation peaks yielded six left-lateralized clusters. We then evaluated the locations of both the individual-study peaks and the clusters against probabilistic functional atlases (cf. anatomical locations, as is typically done) for three candidate brain networks-the language-selective network (Fedorenko, Behr, & Kanwisher, 2011), which supports language processing, the Theory of Mind (ToM) network (Saxe & Kanwisher, 2003), which supports social inferences, and the domain-general Multiple-Demand (MD) network (Duncan, 2010), which supports executive control. These atlases were created by overlaying individual activation maps of participants who performed robust and extensively validated 'localizer' tasks that selectively target each network in question (n = 806 for language; n = 198 for ToM; n = 691 for MD). We found that both the individual-study peaks and the ALE clusters fell primarily within the language network and the ToM network. These results suggest that non-literal processing is supported by both i) mechanisms that process literal linguistic meaning, and ii) mechanisms that support general social inference. They thus undermine a strong divide between literal and non-literal aspects of language and challenge the claim that non-literal processing requires additional executive resources.

Conventionality determines the time course of indirect replies comprehension: An ERP study

Indirect language comprehension requires decoding both the literal meaning and the intended meaning of an utterance, in which pragmatic inference is involved. This study tests the role of conventionality in the time course of indirect reply processing by comparing conventional and non-conventional indirect replies with direct reply, respectively. We constructed discourses which consist of a context and a dialogue with one question (e.g., May I buy a necklace for you) and one reply (e.g., I really have too many). The reply utterance was segmented into three phrases and presented orderly for EEG recording, e.g., with the subject as the first phrase (e.g., I), the adverbial as the second phrase (e.g., really), and the predicate as the third phrase (e.g., have too many). Our results showed that for conventional indirect replies, the second phrase elicited a larger anterior negativity, and the third phrase elicited a larger anterior N400 compared with those in direct replies. By contrast, for the non-conventional indirect reply, only the third phrase elicited a larger late negativity than the direct replies. These findings suggest that conventionality determines the time course of the pragmatic inferences for the most relevant interpretation during indirect replies comprehension.

Interactions within the social brain: Co-activation and connectivity among networks enabling empathy and Theory of Mind

Empathy and Theory of Mind (ToM) have classically been studied as separate social functions, however, recent advances demonstrate the need to investigate the two in interaction: naturalistic settings often blur the distinction of affect and cognition and demand the simultaneous processing of such different stimulus dimensions. Here, we investigate how empathy and ToM related brain networks interact in contexts wherein multiple cognitive and affective demands must be processed simultaneously. Building on the findings of a recent meta-analysis and hierarchical clustering analysis, we perform meta-analytic connectivity modeling to determine patterns of task-context specific network changes. We analyze 140 studies including classical empathy and ToM tasks, as well as complex social tasks. For studies at the intersection of empathy and ToM, neural co-activation patterns included areas typically associated with both empathy and ToM. Network integration is discussed as a means of combining mechanisms across unique behavioral domains. Such integration may enable adaptive behavior in complex, naturalistic social settings that require simultaneous processing of a multitude of different affective and cognitive information.

Linguistic signs in action: The neuropragmatics of speech acts

What makes human communication exceptional is the ability to grasp speaker's intentions beyond what is said verbally. How the brain processes communicative functions is one of the central concerns of the neurobiology of language and pragmatics. Linguistic-pragmatic theories define these functions as speech acts, and various pragmatic traits characterise them at the levels of propositional content, action sequence structure, related commitments and social aspects. Here I discuss recent neurocognitive studies, which have shown that the use of identical linguistic signs in conveying different communicative functions elicits distinct and ultra-rapid neural responses. Interestingly, cortical areas show differential involvement underlying various pragmatic features related to theory-of-mind, emotion and action for specific speech acts expressed with the same utterances. Drawing on a neurocognitive model, I posit that understanding speech acts involves the expectation of typical partner follow-up actions and that this predictive knowledge is immediately reflected in mind and brain.

Understanding an implicated causality: The brain network for processing concessive relations

Concessive relations, often indicated by conjunction words such as although, are semantically and pragmatically more complex than causal relations (expressed using because), as they involve more semantic features such as implicated meaning and negation. However, it remains unclear how linguistic-level complexity is manifested through different brain activities and functional connectivities. This fMRI study investigated how the neural underpinnings of concessive relations differ from those of causal relations. Pragmatically congruent and incongruent words were embedded in causal as well as concessive sentences. The whole-brain analysis revealed that relative to because-congruent sentences, although-congruent sentences evoked increased activations in a left network including IFG, bilateral MFG, mPFC, pMTG, and TPJ. DCM analysis showed that while the functional connectivity from IFG to MFG was commonly involved in processing concessive and causal relations, functional connectivities from pMTG to IFG and from pMTG to TPJ were involved in processing causal and concessive relations, respectively.

Individual Differences in Indirect Speech Act Processing Found Outside the Language Network

Face-to-face communication requires skills that go beyond core language abilities. In dialogue, we routinely make inferences beyond the literal meaning of utterances and distinguish between different speech acts based on, e.g., contextual cues. It is, however, not known whether such communicative skills potentially overlap with core language skills or other capacities, such as theory of mind (ToM). In this functional magnetic resonance imaging (fMRI) study we investigate these questions by capitalizing on individual variation in pragmatic skills in the general population. Based on behavioral data from 199 participants, we selected participants with higher vs. lower pragmatic skills for the fMRI study (N = 57). In the scanner, participants listened to dialogues including a direct or an indirect target utterance. The paradigm allowed participants at the whole group level to (passively) distinguish indirect from direct speech acts, as evidenced by a robust activity difference between these speech acts in an extended language network including ToM areas. Individual differences in pragmatic skills modulated activation in two additional regions outside the core language regions (one cluster in the left lateral parietal cortex and intraparietal sulcus and one in the precuneus). The behavioral results indicate segregation of pragmatic skill from core language and ToM. In conclusion, contextualized and multimodal communication requires a set of interrelated pragmatic processes that are neurocognitively segregated: (1) from core language and (2) partly from ToM.

Resting functional connectivity of the left inferior frontal gyrus with the dorsomedial prefrontal cortex and temporoparietal junction reflects the social network size for active interactions

The size of an individual active social network is a key parameter of human social behavior and is correlated with subjective well-being. However, it remains unknown how the social network size of active interactions is represented in the brain. Here, we examined whether resting-state functional magnetic resonance imaging (fMRI) connectivity is associated with the social network size of active interactions using behavioral data of a large sample (N = 222) on Twitter. Region of interest (ROI)-to-ROI analysis, graph theory analysis, seed-based analysis, and decoding analysis together provided compelling evidence that people who have a large social network size of active interactions, as measured by "reply," show higher fMRI connectivity of the left inferior frontal gyrus with the dorsomedial prefrontal cortex and temporoparietal junction, which represents the core of the theory of mind network. These results demonstrated that people who have a large social network size of active interactions maintain activity of the identified functional connectivity in daily life, possibly providing a mechanism for efficient information transmission between the brain networks related to language and theory-of-mind.

EXPRESS: An eye-tracking investigation of the cognitive processes involved in the comprehension of simple and complex communicative acts

Indirect speech acts communicate more than their literal meaning, and their comprehension relies on the listener's ability to draw the appropriate inferences in a given context. We used eye-tracking to investigate the cognitive processing involved in the comprehension of simple (direct) and complex (unconventional indirect) communicative acts, a more general distinction that applies not only to sincere speech acts, but also to irony and deceit. We recorded the eye movements of 40 participants while they read 60 stories (20 sincere, 20 deceitful, 20 ironic) consisting of a context and a target answer. For each story, we created two different contexts so that the same identical target answer was a simple (direct) and a complex (unconventional indirect) communicative act, respectively. We also assessed the indirectness of simple and complex communicative acts, as well as participants' working memory (WM) and Theory of Mind (ToM). Eye-pattern analysis showed that complex communicative acts were more difficult to understand than simple acts; differences between simple and complex acts held for all the pragmatic phenomena investigated, though processing differences were greater for sincere acts than for irony and deceit. We found a role of indirectness and ToM in the pragmatic processing of simple and complex acts, whereas the role of WM was modest. The present findings underscore the importance of adopting an encompassing theory that can account for different types of indirect speech acts, such as sincere, deceitful and ironic acts; they also suggest the importance of assessing individual differences in inferential and cognitive abilities.

The Social Connectome - Moving Toward Complexity in the Study of Brain Networks and Their Interactions in Social Cognitive and Affective Neuroscience

Over the past 150 years of neuroscientific research, the field has undergone a tremendous evolution. Starting out with lesion-based inference of brain function, functional neuroimaging, introduced in the late 1980s, and increasingly fine-grained and sophisticated methods and analyses now allow us to study the live neural correlates of complex behaviors in individuals and multiple agents simultaneously. Classically, brain-behavior coupling has been studied as an association of a specific area in the brain and a certain behavioral outcome. This has been a crucial first step in understanding brain organization. Social cognitive processes, as well as their neural correlates, have typically been regarded and studied as isolated functions and blobs of neural activation. However, as our understanding of the social brain as an inherently dynamic organ grows, research in the field of social neuroscience is slowly undergoing the necessary evolution from studying individual elements to how these elements interact and their embedding within the overall brain architecture. In this article, we review recent studies that investigate the neural representation of social cognition as interacting, complex, and flexible networks. We discuss studies that identify individual brain networks associated with social affect and cognition, interaction of these networks, and their relevance for disorders of social affect and cognition. This perspective on social cognitive neuroscience can highlight how a more fine-grained understanding of complex network (re-)configurations could improve our understanding of social cognitive deficits in mental disorders such as autism spectrum disorder and schizophrenia, thereby providing new impulses for methods of interventions.

OUP accepted manuscript

During conversations, speech prosody provides important clues about the speaker’s communicative intentions. In many languages, a rising vocal pitch at the end of a sentence typically expresses a question function, whereas a falling pitch suggests a statement. Here, the neurophysiological basis of intonation and speech act understanding were investigated with high-density electroencephalography (EEG) to determine whether prosodic features are reflected at the neurophysiological level. Already approximately 100 ms after the sentence-final word differing in prosody, questions, and statements expressed with the same sentences led to different neurophysiological activity recorded in the event-related potential. Interestingly, low-pass filtered sentences and acoustically matched nonvocal musical signals failed to show any neurophysiological dissociations, thus suggesting that the physical intonation alone cannot explain this modulation. Our results show rapid neurophysiological indexes of prosodic communicative information processing that emerge only when pragmatic and lexico-semantic information are fully expressed. The early enhancement of question-related activity compared with statements was due to sources in the articulatory-motor region, which may reflect the richer action knowledge immanent to questions, namely the expectation of the partner action of answering the question. The present findings demonstrate a neurophysiological correlate of prosodic communicative information processing, which enables humans to rapidly detect and understand speaker intentions in linguistic interactions.

Dynamic Causal Modeling on the Identification of Interacting Networks in the Brain: A Systematic Review

Dynamic causal modeling (DCM) has long been used to characterize effective connectivity within networks of distributed neuronal responses. Previous reviews have highlighted the understanding of the conceptual basis behind DCM and its variants from different aspects. However, no detailed summary or classification research on the task-related effective connectivity of various brain regions has been made formally available so far, and there is also a lack of application analysis of DCM for hemodynamic and electrophysiological measurements. This review aims to analyze the effective connectivity of different brain regions using DCM for different measurement data. We found that, in general, most studies focused on the networks between different cortical regions, and the research on the networks between other deep subcortical nuclei or between them and the cerebral cortex are receiving increasing attention, but far from the same scale. Our analysis also reveals a clear bias towards some task types. Based on these results, we identify and discuss several promising research directions that may help the community to attain a clear understanding of the brain network interactions under different tasks.

The Neural Substrate of Speech Act Recognition

Pragmatic competence demands linguistic, but also communicative, social and cognitive competence. Successful use of language in social interaction requires mutual understanding of the speaker's intentions; without it, a conversation cannot proceed. The term speech act refers to what a speaker intends to accomplish when saying something. The purpose of this study was to contribute to the identification of the neural substrate of speech act recognition and to the characterization of the cognitive processes that may be involved. The recognition of speech acts resulted in greater activation of frontal regions, precuneus and posterior cingulate gyrus. From all cognitive and behavioral measures obtained, only the scores in mental flexibility predicted the change in blood oxygen level dependent (BOLD) signal in the precuneus. These results, support the idea that speech act recognition requires the inference of intention, executive functions, including memory and entails the activation of areas of social cognition that participate in several brain networks i.e., the Intention Processing, the Default Mode and Theory of Mind networks, and areas involved in planning and guiding behavior.

Frontotemporal dementia, music perception and social cognition share neurobiological circuits: A meta-analysis

Frontotemporal dementia (FTD) is a neurodegenerative disease that presents with profound changes in social cognition. Music might be a sensitive probe for social cognition abilities, but underlying neurobiological substrates are unclear. We performed a meta-analysis of voxel-based morphometry studies in FTD patients and functional MRI studies for music perception and social cognition tasks in cognitively normal controls to identify robust patterns of atrophy (FTD) or activation (music perception or social cognition). Conjunction analyses were performed to identify overlapping brain regions. In total 303 articles were included: 53 for FTD (n = 1153 patients, 42.5% female; 1337 controls, 53.8% female), 28 for music perception (n = 540, 51.8% female) and 222 for social cognition in controls (n = 5664, 50.2% female). We observed considerable overlap in atrophy patterns associated with FTD, and functional activation associated with music perception and social cognition, mostly encompassing the ventral language network. We further observed overlap across all three modalities in mesolimbic, basal forebrain and striatal regions. The results of our meta-analysis suggest that music perception and social cognition share neurobiological circuits that are affected in FTD. This supports the idea that music might be a sensitive probe for social cognition abilities with implications for diagnosis and monitoring.

Understanding particularized and generalized conversational implicatures: Is theory-of-mind necessary?

A speaker's intended meaning can be inferred from an utterance with or without reference to its context for particularized implicature (PI) and/or generalized implicature (GI). Although previous studies have separately revealed the neural correlates of PI and GI comprehension, it remains controversial whether they share theory-of-mind (ToM) related inferential processes. Here we address this issue using functional MRI (fMRI) and transcranial direct current stimulation (tDCS). Participants listened to single-turn dialogues where the reply was indirect with either PI or GI or was direct for control conditions (i.e., PIC and GIC). Results showed that PI and GI comprehension shared the multivariate fMRI patterns of language processing; in contrast, the ToM-related pattern was only elicited by PI comprehension, either at the whole-brain level or within dorsal medial prefrontal cortex (dmPFC). Moreover, stimulating right TPJ exclusively affected PI comprehension. These findings suggest that understanding PI, but not GI, requires ToM-related inferential processes.

Brain signatures predict communicative function of speech production in interaction

People normally know what they want to communicate before they start speaking. However, brain indicators of communication are typically observed only after speech act onset, and it is unclear when any anticipatory brain activity prior to speaking might first emerge, along with the communicative intentions it possibly reflects. Here, we investigated brain activity prior to the production of different speech act types, request and naming actions performed by uttering single words embedded into language games with a partner, similar to natural communication. Starting ca. 600 msec before speech onset, an event-related potential maximal at fronto-central electrodes, which resembled the Readiness Potential, was larger when preparing requests compared to naming actions. Analysis of the cortical sources of this anticipatory brain potential suggests a relatively stronger involvement of fronto-central motor regions for requests, which may reflect the speaker's expectation of the partner actions typically following requests, e.g., the handing over of a requested object. Our results indicate that different neuronal circuits underlying the processing of different speech act types activate already before speaking. Results are discussed in light of previous work addressing the neural basis of speech act understanding and predictive brain indexes of language comprehension.

Neurophysiological evidence for rapid processing of verbal and gestural information in understanding communicative actions

During everyday social interaction, gestures are a fundamental part of human communication. The communicative pragmatic role of hand gestures and their interaction with spoken language has been documented at the earliest stage of language development, in which two types of indexical gestures are most prominent: the pointing gesture for directing attention to objects and the give-me gesture for making requests. Here we study, in adult human participants, the neurophysiological signatures of gestural-linguistic acts of communicating the pragmatic intentions of naming and requesting by simultaneously presenting written words and gestures. Already at ~150 ms, brain responses diverged between naming and request actions expressed by word-gesture combination, whereas the same gestures presented in isolation elicited their earliest neurophysiological dissociations significantly later (at ~210 ms). There was an early enhancement of request-evoked brain activity as compared with naming, which was due to sources in the frontocentral cortex, consistent with access to action knowledge in request understanding. In addition, an enhanced N400-like response indicated late semantic integration of gesture-language interaction. The present study demonstrates that word-gesture combinations used to express communicative pragmatic intentions speed up the brain correlates of comprehension processes – compared with gesture-only understanding – thereby calling into question current serial linguistic models viewing pragmatic function decoding at the end of a language comprehension cascade. Instead, information about the social-interactive role of communicative acts is processed instantaneously.

Posterior cingulate cortex can be a regulatory modulator of the default mode network in task-negative state

In recent years, the regulation of brain networks and interactions between different brain regions have become important issues in neuroscience. Effective connectivity can be employed to understand the modulatory mechanisms of brain networks. Previous studies have used the task-positive mode to examine effective connectivity between brain regions and very few studies have considered the task-negative mode to explore effective connectivity using electroencephalography (EEG). In the present study, high-density EEG experiments were conducted in 85 participants to measure EEG effective connectivity in relevant default mode network (DMN) brain regions (i.e., the medial prefrontal cortex [mPFC], posterior cingulate cortex [PCC], precuneus, and right frontal and left occipital regions) to observe the effects of different task-negative modes (eyes-open/eyes-closed state) and personality traits (introversion/extroversion). The results showed that in the eyes-closed state, the PCC had significantly increased effective connectivity and played a prominent role as a regulatory modulator of outflow to other regions mediated by alpha rhythms. The mPFC was a regulatory modulator of outflow in the eyes-open state mediated by delta rhythms. The introvert group showed stronger co-modulations in the relevant DMN regions than the extrovert group.

A Quantitative Meta-analysis of Neuroimaging Studies of Pragmatic Language Comprehension: In Search of a Universal Neural Substrate

Pragmatics may be defined as the ability to communicate by expressing and recognizing intentions. The objective of this meta-analysis was to identify neural substrates for comprehension of pragmatic content in general, as well as the differences between pragmatic forms, and to describe if there is differential recruitment of brain areas according to natural language. This meta-analysis included 48 functional magnetic resonance imaging studies that reported pragmatic versus literal language contrasts. The pragmatic forms were speech acts, metaphors, idioms, and irony. Effect Size-Signed Differential Mapping software was used to calculate the mean for all contrasts as well as for each pragmatic form, and make comparisons among all forms. Due to variations in pragmatic content configuration such as natural language, stimulus modality, and writing systems, these variations were also analyzed with subgroups' analyses. The analyses found a highly reproducible bilateral fronto-temporal and medial prefrontal cortex network for pragmatic comprehension. Each pragmatic form showed a specific convergence pattern within this bilateral network. Natural language analyses showed that fronto-temporal regions were recruited by Germanic languages, while only left frontal areas were recruited by Romance languages, and right medial prefrontal cortex by Japanese. In conclusion, pragmatic language comprehension involves classical language areas in bilateral perisylvian regions, along with the medial prefrontal cortex, an area involved in social cognition. Together, these areas could represent the "pragmatic language network". Nonetheless, when proposing a universal neural substrate for all forms of pragmatic language, the diversity among studies in terms of pragmatic form, and configuration, must be taken into consideration.

Oscillatory brain activity differentially reflects false belief understanding and complementation syntax processing

False belief understanding (FBU) enables people to consider conflicting beliefs about the same situation. While language has been demonstrated to be a correlate of FBU, there is still controversy about the extent to which a specific aspect of language, complementation syntax, is a necessary condition for FBU. The present study tested an important notion from the debate proposing that complementation syntax task is redundant to FBU measures. Specifically, we examined electrophysiological correlates of false belief, false complementation, and their respective true conditions in adults using electroencephalography (EEG), focusing on indices of oscillatory brain activity and large-scale connectivity. The results showed strong modulation of parieto-occipital alpha (8-12 Hz) and beta (13-20 Hz) power by the experimental manipulations, with heightened sustained alpha power reflective of effortful internal processing observed in the false compared to the true conditions and reliable beta power reductions sensitive to mentalizing and/or syntactic demands in the belief versus the complementation conditions. In addition, higher coupling between parieto-occipital regions and widespread frontal sites in the beta band was found for the false-belief condition selectively. The result of divergence in beta oscillatory activity and in connectivity between false belief and false complementation does not support the redundancy hypothesis.

Altered Neural Activity during Irony Comprehension in Unaffected First-Degree Relatives of Schizophrenia Patients-An fMRI Study

Irony is a type of figurative language in which the literal meaning of the expression is the opposite of what the speaker intends to communicate. Even though schizophrenic patients are known as typically impaired in irony comprehension and in the underlying neural functions, to date no one has explored the neural correlates of figurative language comprehension in first-degree relatives of schizophrenic patients. In the present study, we examined the neural correlates of irony understanding in schizophrenic patients and in unaffected first-degree relatives of patients compared to healthy adults with functional MRI. Our aim was to investigate if possible alterations of the neural circuits supporting irony comprehension in first-degree relatives of patients with schizophrenia would fulfill the familiality criterion of an endophenotype. We examined 12 schizophrenic patients, 12 first-degree relatives of schizophrenia patients and 12 healthy controls with functional MRI while they were performing irony and control tasks. Different phases of irony processing were examined, such as context processing and ironic statement comprehension. Patients had significantly more difficulty understanding irony than controls or relatives. Patients also showed markedly different neural activation pattern compared to controls in both stages of irony processing. Although no significant differences were found in the performance of the irony tasks between the control group and the relative group, during the fMRI analysis, the relatives showed stronger brain activity in the left dorsolateral prefrontal cortex during the context processing phase of irony tasks than the control group. However, the controls demonstrated higher activations in the left dorsomedial prefrontal cortex and in the right inferior frontal gyrus during the ironic statement phase of the irony tasks than the relative group. Our results show that despite good task performance, first-degree relatives of schizophrenia patients had alterations in the neural circuits during irony processing. Thus, we suggest that neural alteration of irony comprehension could be a potential endophenotypic marker of schizophrenia.

Effects of contextual relevance on pragmatic inference during conversation: An fMRI study

Contextual relevance, which is vital for understanding conversational implicatures (CI), engages both the frontal-temporal language and theory-of-mind networks. Here we investigate how contextual relevance affects CI processing and regulates the connectivity between CI-processing-related brain regions. Participants listened to dialogues in which the level of contextual relevance to dialogue-final utterance (reply) was manipulated. This utterance was either direct, indirect but relevant, irrelevant with contextual hint, or irrelevant with no contextual hint. Results indicated that compared with direct replies, indirect replies showed increased activations in bilateral IFG, bilateral MTG, bilateral TPJ, dmPFC, and precuneus, and increased connectivity between rTPJ/dmPFC and both IFG and MTG. Moreover, irrelevant replies activated right MTG along an anterior-posterior gradient as a function of the level of irrelevance. Our study provides novel evidence concerning how the language and theory-of-mind networks interact for pragmatic inference and how the processing of CI is modulated by level of contextual relevance.

Neural reuse of action perception circuits for language, concepts and communication

Neurocognitive and neurolinguistics theories make explicit statements relating specialized cognitive and linguistic processes to specific brain loci. These linking hypotheses are in need of neurobiological justification and explanation. Recent mathematical models of human language mechanisms constrained by fundamental neuroscience principles and established knowledge about comparative neuroanatomy offer explanations for where, when and how language is processed in the human brain. In these models, network structure and connectivity along with action- and perception-induced correlation of neuronal activity co-determine neurocognitive mechanisms. Language learning leads to the formation of action perception circuits (APCs) with specific distributions across cortical areas. Cognitive and linguistic processes such as speech production, comprehension, verbal working memory and prediction are modelled by activity dynamics in these APCs, and combinatorial and communicative-interactive knowledge is organized in the dynamics within, and connections between APCs. The network models and, in particular, the concept of distributionally-specific circuits, can account for some previously not well understood facts about the cortical 'hubs' for semantic processing and the motor system's role in language understanding and speech sound recognition. A review of experimental data evaluates predictions of the APC model and alternative theories, also providing detailed discussion of some seemingly contradictory findings. Throughout, recent disputes about the role of mirror neurons and grounded cognition in language and communication are assessed critically.

Neural systems for evaluating speaker (Un)believability

Our voice provides salient cues about how confident we sound, which promotes inferences about how believable we are. However, the neural mechanisms involved in these social inferences are largely unknown. Employing functional magnetic resonance imaging, we examined the brain networks and individual differences underlying the evaluation of speaker believability from vocal expressions. Participants (n = 26) listened to statements produced in a confident, unconfident, or "prosodically unmarked" (neutral) voice, and judged how believable the speaker was on a 4-point scale. We found frontal-temporal networks were activated for different levels of confidence, with the left superior and inferior frontal gyrus more activated for confident statements, the right superior temporal gyrus for unconfident expressions, and bilateral cerebellum for statements in a neutral voice. Based on listener's believability judgment, we observed increased activation in the right superior parietal lobule (SPL) associated with higher believability, while increased left posterior central gyrus (PoCG) was associated with less believability. A psychophysiological interaction analysis found that the anterior cingulate cortex and bilateral caudate were connected to the right SPL when higher believability judgments were made, while supplementary motor area was connected with the left PoCG when lower believability judgments were made. Personal characteristics, such as interpersonal reactivity and the individual tendency to trust others, modulated the brain activations and the functional connectivity when making believability judgments. In sum, our data pinpoint neural mechanisms that are involved when inferring one's believability from a speaker's voice and establish ways that these mechanisms are modulated by individual characteristics of a listener. Hum Brain Mapp 38:3732-3749, 2017. © 2017 Wiley Periodicals, Inc.