Neural substrates of semantic relationships: Common and distinct left-frontal activities for generation of synonyms vs. antonyms

Neural representations of perspectival shapes and attentional effects: Evidence from fMRI and MEG

Does the human brain represent perspectival shapes, i.e., viewpoint-dependent object shapes, especially in relatively higher-level visual areas such as the lateral occipital cortex? What is the temporal profile of the appearance and disappearance of neural representations of perspectival shapes? And how does attention influence these neural representations? To answer these questions, we employed functional magnetic resonance imaging (fMRI), magnetoencephalography (MEG), and multivariate decoding techniques to investigate spatiotemporal neural representations of perspectival shapes. Participants viewed rotated objects along with the corresponding objective shapes and perspectival shapes (i.e., rotated round, round, and oval) while we measured their brain activities. Our results revealed that shape classifiers trained on the basic shapes (i.e., round and oval) consistently identified neural representations in the lateral occipital cortex corresponding to the perspectival shapes of the viewed objects regardless of attentional manipulations. Additionally, this classification tendency toward the perspectival shapes emerged approximately 200 ms after stimulus presentation. Moreover, attention influenced the spatial dimension as the regions showing the perspectival shape classification tendency propagated from the occipital lobe to the temporal lobe. As for the temporal dimension, attention led to a more robust and enduring classification tendency towards perspectival shapes. In summary, our study outlines a spatiotemporal neural profile for perspectival shapes that suggests a greater degree of perspectival representation than is often acknowledged.

Topology of the lateral visual system: The fundus of the superior temporal sulcus and parietal area H connect nonvisual cerebrum to the lateral occipital lobe

BACKGROUND AND PURPOSE

Mapping the topology of the visual system is critical for understanding how complex cognitive processes like reading can occur. We aim to describe the connectivity of the visual system to understand how the cerebrum accesses visual information in the lateral occipital lobe.

METHODS

Using meta-analytic software focused on task-based functional MRI studies, an activation likelihood estimation (ALE) of the visual network was created. Regions of interest corresponding to the cortical parcellation scheme previously published under the Human Connectome Project were co-registered onto the ALE to identify the hub-like regions of the visual network. Diffusion Spectrum Imaging-based fiber tractography was performed to determine the structural connectivity of these regions with extraoccipital cortices.

RESULTS

The fundus of the superior temporal sulcus (FST) and parietal area H (PH) were identified as hub-like regions for the visual network. FST and PH demonstrated several areas of coactivation beyond the occipital lobe and visual network. Furthermore, these parcellations were highly interconnected with other cortical regions throughout extraoccipital cortices related to their nonvisual functional roles. A cortical model demonstrating connections to these hub-like areas was created.

CONCLUSIONS

FST and PH are two hub-like areas that demonstrate extensive functional coactivation and structural connections to nonvisual cerebrum. Their structural interconnectedness with language cortices along with the abnormal activation of areas commonly located in the temporo-occipital region in dyslexic individuals suggests possible important roles of FST and PH in the integration of information related to language and reading. Future studies should refine our model by examining the functional roles of these hub areas and their clinical significance.

The critical role of interference control in metaphor comprehension evidenced by the drift-diffusion model

We address the question of, among several executive functions, which one has a strong influence on metaphor comprehension. To this end, participants took part in a metaphor comprehension task where metaphors had varying levels of familiarity (familiar vs. novel metaphors) with different conditions of context (supporting vs. opposing contexts). We scrutinized each participant's detailed executive functions using seven neuropsychological tests. More interestingly, we modelled their responses in metaphor comprehension using the drift-diffusion model, in an attempt to provide more systematic accounts of the processes underlying metaphor comprehension. Results showed that there were significant negative correlations between response times in metaphor comprehension and scores of the Controlled Oral Word Association Test (COWAT)-Semantic, suggesting that better performances in comprehending metaphors were strongly associated with better interference control. Using the drift-diffusion model, we found that the familiarity, compared to context, had greater leverage in the decision process for metaphor comprehension. Moreover, individuals with better performance in the COWAT-Semantic test demonstrated higher drift rates. In conclusion, with more fine-grained analysis of the decisions involved in metaphor comprehension using the drift-diffusion model, we argue that interference control plays an important role in processing metaphors.

Altered brain language network in idiopathic peripheral facial paralysis patients with dysarthria

BACKGROUND

Dysarthria is one of the common symptoms of facial paralysis (FP). This study aimed to investigate functional alterations in the brain language network in early idiopathic peripheral FP patients with dysarthria using resting-state functional magnetic resonance imaging (fMRI).

METHODS

A total of 45 cases of FP (left 22, right 23) and 34 cases of healthy control (HC) were recruited into this study. The data of patients with left-side FP and matched controls (17 cases) were flipped from left to right, and the brain regions were defined as ipsilateral and contralateral regions. The FC of 16 ROIs in classical language centers and regions that may be involved in language function were calculated. After identifying the differences of FC between the two groups, the correlation analysis between altered FC and TFGS score of oral muscle movement in FP group were analyzed.

RESULTS

The FC between bilateral language regions has a significantly decreased trend in FP group compared with HC group (P<0.05). The ipsilateral inferior frontal gyrus, superior temporal gyrus, and middle temporal gyrus exhibited significantly decreased FC with multiple brain regions. In addition, we found that thalamus and cerebellum also with a significant alteration in FC in FP patients indicating that these two regions may also be involved in the mechanism of dysarthria in FP. The correlation analysis results indicated that the decrease of FC was positively correlated with the severity of oral paralysis.

CONCLUSIONS

Idiopathic peripheral FP with dysarthria induces several FC alterations in the brain language network. The severity of oral paralysis is associated with these functional alterations.

Evaluating the roles of left middle frontal gyrus in word production using electrocorticography

To assess the specific roles of left middle frontal gyrus (LMFG) in word production, electrocorticography signals were recorded from an epilepsy patient when he participated in language tasks. We found three sites of LMFG showed high-gamma perturbations with distinct patterns across tasks; and neural activities elicited in the same tasks shared similar patterns, while those elicited by stimuli leading to the same articulations did not. These findings confirmed that the LMFG takes active parts in word production, and suggested that it may serve as a temporal perceptual information storage space, supporting the hierarchical state feedback control model of word production.

Effects of Transcranial Direct Current Stimulation on Neural Networks in Young and Older Adults

Transcranial direct current stimulation (tDCS) may be a viable tool to improve motor and cognitive function in advanced age. However, although a number of studies have demonstrated improved cognitive performance in older adults, other studies have failed to show restorative effects. The neural effects of beneficial stimulation response in both age groups is lacking. In the current study, tDCS was administered during simultaneous fMRI in 42 healthy young and older participants. Semantic word generation and motor speech baseline tasks were used to investigate behavioral and neural effects of uni- and bihemispheric motor cortex tDCS in a three-way, crossover, sham tDCS controlled design. Independent components analysis assessed differences in task-related activity between the two age groups and tDCS effects at the network level. We also explored whether laterality of language network organization was effected by tDCS. Behaviorally, both active tDCS conditions significantly improved semantic word retrieval performance in young and older adults and were comparable between groups and stimulation conditions. Network-level tDCS effects were identified in the ventral and dorsal anterior cingulate networks in the combined sample during semantic fluency and motor speech tasks. In addition, a shift toward enhanced left laterality was identified in the older adults for both active stimulation conditions. Thus, tDCS results in common network-level modulations and behavioral improvements for both age groups, with an additional effect of increasing left laterality in older adults.

"Decoding versus comprehension": Brain responses underlying reading comprehension in children with autism

Despite intact decoding ability, deficits in reading comprehension are relatively common in children with autism spectrum disorders (ASD). However, few neuroimaging studies have tested the neural bases of this specific profile of reading deficit in ASD. This fMRI study examined activation and synchronization of the brain's reading network in children with ASD with specific reading comprehension deficits during a word similarities task. Thirteen typically developing children and 18 children with ASD performed the task in the MRI scanner. No statistically significant group differences in functional activation were observed; however, children with ASD showed decreased functional connectivity between the left inferior frontal gyrus (LIFG) and the left inferior occipital gyrus (LIOG). In addition, reading comprehension ability significantly positively predicted functional connectivity between the LIFG and left thalamus (LTHAL) among all subjects. The results of this study provide evidence for altered recruitment of reading-related neural resources in ASD children and suggest specific weaknesses in top-down modulation of semantic processing.

The regional neuronal activity in left posterior middle temporal gyrus is correlated with the severity of chronic aphasia

BACKGROUND

Aphasia is one of the most disabling cognitive deficits affecting >2 million people in the USA. The neuroimaging characteristics of chronic aphasic patients (>6 months post onset) remain largely unknown.

OBJECTIVE

The objective of this study was to investigate the regional signal changes of spontaneous neuronal activity of brain and the inter-regional connectivity in chronic aphasia.

MATERIALS AND METHODS

Resting-state blood oxygenation level-dependent functional magnetic resonance imaging (fMRI) was used to obtain fMRI data from 17 chronic aphasic patients and 20 healthy control subjects in a Siemens Verio 3.0T MR Scanner. The amplitude of low-frequency fluctuation (ALFF) was determined, which directly reflects the regional neuronal activity. The functional connectivity (FC) of fMRI was assessed using a seed voxel linear correlation approach. The severity of aphasia was evaluated by aphasia quotient (AQ) scores obtained from Western Aphasia Battery test.

RESULTS

Compared with normal subjects, aphasic patients showed decreased ALFF values in the regions of left posterior middle temporal gyrus (PMTG), left medial prefrontal gyrus, and right cerebellum. The ALFF values in left PMTG showed strong positive correlation with the AQ score (coefficient r=0.79, P<0.05). There was a positive FC in chronic aphasia between left PMTG and left inferior temporal gyrus (BA20), fusiform gyrus (BA37), and inferior frontal gyrus (BA47\45\44).

CONCLUSION

Left PMTG might play an important role in language dysfunction of chronic aphasia, and ALFF value might be a promising indicator to evaluate the severity of aphasia.

Examining Method Effect of Synonym and Antonym Test in Verbal Abilities Measure

Many researchers have assumed that different methods could be substituted to measure the same attributes in assessment. Various models have been developed to accommodate the amount of variance attributable to the methods but these models application in empirical research is rare. The present study applied one of those models to examine whether method effects were presents in synonym and antonym tests. Study participants were 3,469 applicants to graduate school. The instrument used was the Graduate Academic Potential Test (PAPS), which includes synonym and antonym questions to measure verbal abilities. Our analysis showed that measurement models that using correlated trait-correlated methods minus one, CT-C(M-1), that separated trait and method effect into distinct latent constructs yielded slightly better values for multiple goodness-of-fit indices than one factor model. However, either for the synonym or antonym items, the proportion of variance accounted for by the method is smaller than trait variance. The correlation between factor scores of both methods is high (r = 0.994). These findings confirm that synonym and antonym tests represent the same attribute so that both tests cannot be treated as two unique methods for measuring verbal ability.

The Relationship between Frontotemporal Effective Connectivity during Picture Naming, Behavior, and Preserved Cortical Tissue in Chronic Aphasia

While several studies of task-based effective connectivity of normal language processing exist, little is known about the functional reorganization of language networks in patients with stroke-induced chronic aphasia. During oral picture naming, activation in neurologically intact individuals is found in "classic" language regions involved with retrieval of lexical concepts [e.g., left middle temporal gyrus (LMTG)], word form encoding [e.g., left posterior superior temporal gyrus, (LpSTG)], and controlled retrieval of semantic and phonological information [e.g., left inferior frontal gyrus (LIFG)] as well as domain-general regions within the multiple demands network [e.g., left middle frontal gyrus (LMFG)]. After stroke, lesions to specific parts of the left hemisphere language network force reorganization of this system. While individuals with aphasia have been found to recruit similar regions for language tasks as healthy controls, the relationship between the dynamic functioning of the language network and individual differences in underlying neural structure and behavioral performance is still unknown. Therefore, in the present study, we used dynamic causal modeling (DCM) to investigate differences between individuals with aphasia and healthy controls in terms of task-induced regional interactions between three regions (i.e., LIFG, LMFG, and LMTG) vital for picture naming. The DCM model space was organized according to exogenous input to these regions and partitioned into separate families. At the model level, random effects family wise Bayesian Model Selection revealed that models with driving input to LIFG best fit the control data whereas models with driving input to LMFG best fit the patient data. At the parameter level, a significant between-group difference in the connection strength from LMTG to LIFG was seen. Within the patient group, several significant relationships between network connectivity parameters, spared cortical tissue, and behavior were observed. Overall, this study provides some preliminary findings regarding how neural networks for language reorganize for individuals with aphasia and how brain connectivity relates to underlying structural integrity and task performance.

Choosing words: left hemisphere, right hemisphere, or both? Perspective on the lateralization of word retrieval

Language is considered to be one of the most lateralized human brain functions. Left hemisphere dominance for language has been consistently confirmed in clinical and experimental settings and constitutes one of the main axioms of neurology and neuroscience. However, functional neuroimaging studies are finding that the right hemisphere also plays a role in diverse language functions. Critically, the right hemisphere may also compensate for the loss or degradation of language functions following extensive stroke-induced damage to the left hemisphere. Here, we review studies that focus on our ability to choose words as we speak. Although fluidly performed in individuals with intact language, this process is routinely compromised in aphasic patients. We suggest that parceling word retrieval into its subprocesses-lexical activation and lexical selection-and examining which of these can be compensated for after left hemisphere stroke can advance the understanding of the lateralization of word retrieval in speech production. In particular, the domain-general nature of the brain regions associated with each process may be a helpful indicator of the right hemisphere's propensity for compensation.

Cortisol Response to Stress in Adults with Attention Deficit Hyperactivity Disorder

BACKGROUND

Differences in the cortisol response have been reported between children exhibiting the inattentive and hyperactive/impulsive subtypes of attention deficit hyperactivity disorder. However, there is no such information about adults. The aim of the present study was to determine the possible differences between the combined and inattentive subtypes in the cortisol response to stress.

METHODS

Ninety-six adults with attention deficit hyperactivity disorder, 38 inattentive and 58 combined, without any medical or psychiatric comorbidities and 25 healthy controls were included. The Trier Social Stress Test was used to assess physiological stress responses. Clinical data and subjective stress levels, including the Perceived Stress Scale, were also recorded.

RESULTS

No significant differences in the cortisol response to the Trier Social Stress Test were found between patients and controls. However, albeit there were no basal differences, lower cortisol levels at 15 (P=.015), 30 (P=.015), and 45 minutes (P=.045) were observed in the combined compared with the inattentive subtype after the stress induction; these differences disappeared 60 minutes after the stress. In contrast, the subjective stress responses showed significant differences between attention deficit hyperactivity disorder patients and controls (P<.001), but no differences were seen between attention deficit hyperactivity disorder subtypes. In turn, subjective stress measures, such as the Perceived Stress Scale, positively correlated with the whole cortisol stress response (P<.027).

CONCLUSIONS

Both the combined and inattentive attention deficit hyperactivity disorder adults exhibited a normal cortisol response to stress when challenged. Nevertheless, the inattentive patients displayed a higher level of cortisol after stress compared with the combined patients. Despite the differences in the cortisol response, adults with attention deficit hyperactivity disorder reported high levels of subjective stress in their every-day life.

Is black always the opposite of white? An investigation on the comprehension of antonyms in people with schizophrenia and in healthy participants

The present investigation sought to expand our understanding of the cognitive processes underlying the recognition of antonyms and to evaluate whether these processes differed in patients with schizophrenia and in healthy controls. Antonymy is the most robust of the lexico-semantic relations and is relevant to both the mental organization of the lexicon and the organization of coherent discourse, as attested by the resurgence of interest in antonymy in the linguistic and psychological domains. In contrast, the vast literature on semantic processing in schizophrenia almost ignored antonymy. In this study, we tested the online comprehension of antonyms in 39 Italian patients with paranoid schizophrenia and in an equal number of pairwise-matched healthy controls. Participants read a definitional sentence fragment (e.g., the opposite of black is), followed by the correct antonym (white) or by a semantically unrelated word (nice), and judged whether or not the target word was correct. Patients were rather accurate in identifying antonyms, but compared to controls, they showed longer response times and higher priming scores, suggesting an exaggerated contextual facilitation. Presumably, this reflects a deficient controlled semantic processing and an overreliance on stored semantic representations.

Attention deficit hyperactivity disorder in the European adult population: prevalence, disease awareness, and treatment guidelines

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) is a chronic neurobiological disorder with childhood onset and persistence into adolescence and adulthood.

METHODS

Our literature review reports scientific publications and guidelines on the treatment of adult ADHD, with a particular focus on European countries, identified by literature searches in Medline and Embase. The final literature search was performed in July 2012, incorporating literature from 1974 to 2012. The primary research parameters were 'Europe' (including single European countries), 'ADHD', 'attention deficit disorder', 'attention deficit', 'attention disorder', and 'hyperactivity'. Secondary search parameters were 'comorbid', 'epidemiology' or 'prevalence', 'disease management', 'drug therapy', or 'therapy'. The main searches were also limited to adults and English language publications. The papers identified by this literature review were selected for inclusion by consensus of the authors based on clinical relevance.

RESULTS

Appropriate resources for the diagnosis and treatment of adult ADHD in Europe are scarce, and many cases go untreated, particularly because of the frequent presence of psychiatric comorbidities. Apart from atomoxetine, and an extended-release form of methylphenidate in Germany, no other medications have been approved for starting treatment in adult ADHD patients in the European Union. However, a variety of stimulant and non-stimulant medications are used off-label, and a number of studies have confirmed that these medications are well tolerated and effective in adult patients with ADHD.

CONCLUSIONS

Our results emphasize the need for broader access to effective treatments for adult ADHD patients in Europe.

The role of polarity in antonym and synonym conceptual knowledge: evidence from stroke aphasia and multidimensional ratings of abstract words

This study describes an investigation of different types of semantic relationship among abstract words: antonyms (e.g. good-bad), synonyms (e.g. good-great), non-antonymous, non-synonymous associates (NANSAs; e.g. good-fun) and unrelated words (e.g. good-late). The comprehension and semantic properties of these words were examined using two distinct methodologies. Experiment 1 tested the comprehension of pairs of abstract words in three patients with global aphasia using a spoken word to written word matching paradigm. Contrary to expectations, all three patients showed superior antonym comprehension compared with synonyms or NANSAs, discriminating antonyms with a similar level of accuracy as unrelated words. Experiment 2 aimed to explore the content or semantic attributes of the abstract words used in Experiment 1 through the generation of control ratings across nine cognitive dimensions (sensation, action, thought, emotion, social interaction, space, time, quantity and polarity). Discrepancy analyses revealed that antonyms were as or more similar to one another than synonyms on all but one measure: polarity. The results of Experiment 2 provide a possible explanation for the novel pattern of neuropsychological data observed in Experiment 1, namely that polarity information is more important than other semantic attributes when discriminating the meaning of abstract words. It is argued that polarity is a critical semantic attribute of abstract words, and that simple 'dissimilarity' metrics mask fundamental consistencies in the semantic representation of antonyms. It is also suggested that mapping abstract semantic space requires the identification and quantification of the contribution made to abstract concepts by not only sensorimotor and emotional information but also a host of other cognitive dimensions.

A review and synthesis of the first 20 years of PET and fMRI studies of heard speech, spoken language and reading

The anatomy of language has been investigated with PET or fMRI for more than 20 years. Here I attempt to provide an overview of the brain areas associated with heard speech, speech production and reading. The conclusions of many hundreds of studies were considered, grouped according to the type of processing, and reported in the order that they were published. Many findings have been replicated time and time again leading to some consistent and undisputable conclusions. These are summarised in an anatomical model that indicates the location of the language areas and the most consistent functions that have been assigned to them. The implications for cognitive models of language processing are also considered. In particular, a distinction can be made between processes that are localized to specific structures (e.g. sensory and motor processing) and processes where specialisation arises in the distributed pattern of activation over many different areas that each participate in multiple functions. For example, phonological processing of heard speech is supported by the functional integration of auditory processing and articulation; and orthographic processing is supported by the functional integration of visual processing, articulation and semantics. Future studies will undoubtedly be able to improve the spatial precision with which functional regions can be dissociated but the greatest challenge will be to understand how different brain regions interact with one another in their attempts to comprehend and produce language.

Neural bases of falsification in conditional proposition testing: evidence from an fMRI study

The ability of testing the validity of a conditional statement is important in our everyday life. However, the brain mechanisms underlying this process, especially falsification process which is important in daily life, but especially crucial to scientific reasoning and research is not as yet completely clear. Therefore, in the present study, we used event-related functional magnetic resonance imaging (fMRI) to examine the neural bases of the falsification process in testing the validity of a conditional statement as used in Wason's (1966) selection task. Our fMRI results showed that: (1) compared with the baseline condition, both Falsification (by using Modus Ponens, and Modus Tollens) and Non-Falsification conditions (affirming the consequent, and denying the antecedent) activated the left frontal areas (BA44/45, or BA6), and basal ganglia, the areas previously found in the rule-guided conditional reasoning operations; the parietal area (BA40, BA7) for recruiting cognitive resources to represent and maintain the different evidential information in working memory. (2) The left middle frontal gyrus (BA9) and cerebellum were shown to be activated in the contrast of Falsification condition versus Non-Falsification condition and in the contrast of MT versus Non-Falsification condition. These results indicated that the left middle frontal gyrus (BA9) might be the key brain region involved in the falsification process of conditional statement for which abstracting and integrating logical relationships, and inhibiting the distraction of the irrelevant information were the essential processes. Moreover, the cerebellum was found to be responsible for constructing an internal working model. In addition, our brain imaging results might support the dual-process theory of reasoning.

Resting-state brain activity in adult males who stutter

Although developmental stuttering has been extensively studied with structural and task-based functional magnetic resonance imaging (fMRI), few studies have focused on resting-state brain activity in this disorder. We investigated resting-state brain activity of stuttering subjects by analyzing the amplitude of low-frequency fluctuation (ALFF), region of interest (ROI)-based functional connectivity (FC) and independent component analysis (ICA)-based FC. Forty-four adult males with developmental stuttering and 46 age-matched fluent male controls were scanned using resting-state fMRI. ALFF, ROI-based FCs and ICA-based FCs were compared between male stuttering subjects and fluent controls in a voxel-wise manner. Compared with fluent controls, stuttering subjects showed increased ALFF in left brain areas related to speech motor and auditory functions and bilateral prefrontal cortices related to cognitive control. However, stuttering subjects showed decreased ALFF in the left posterior language reception area and bilateral non-speech motor areas. ROI-based FC analysis revealed decreased FC between the posterior language area involved in the perception and decoding of sensory information and anterior brain area involved in the initiation of speech motor function, as well as increased FC within anterior or posterior speech- and language-associated areas and between the prefrontal areas and default-mode network (DMN) in stuttering subjects. ICA showed that stuttering subjects had decreased FC in the DMN and increased FC in the sensorimotor network. Our findings support the concept that stuttering subjects have deficits in multiple functional systems (motor, language, auditory and DMN) and in the connections between them.

A Generative Model of Speech Production in Broca's and Wernicke's Areas

Speech production involves the generation of an auditory signal from the articulators and vocal tract. When the intended auditory signal does not match the produced sounds, subsequent articulatory commands can be adjusted to reduce the difference between the intended and produced sounds. This requires an internal model of the intended speech output that can be compared to the produced speech. The aim of this functional imaging study was to identify brain activation related to the internal model of speech production after activation related to vocalization, auditory feedback, and movement in the articulators had been controlled. There were four conditions: silent articulation of speech, non-speech mouth movements, finger tapping, and visual fixation. In the speech conditions, participants produced the mouth movements associated with the words “one” and “three.” We eliminated auditory feedback from the spoken output by instructing participants to articulate these words without producing any sound. The non-speech mouth movement conditions involved lip pursing and tongue protrusions to control for movement in the articulators. The main difference between our speech and non-speech mouth movement conditions is that prior experience producing speech sounds leads to the automatic and covert generation of auditory and phonological associations that may play a role in predicting auditory feedback. We found that, relative to non-speech mouth movements, silent speech activated Broca’s area in the left dorsal pars opercularis and Wernicke’s area in the left posterior superior temporal sulcus. We discuss these results in the context of a generative model of speech production and propose that Broca’s and Wernicke’s areas may be involved in predicting the speech output that follows articulation. These predictions could provide a mechanism by which rapid movement of the articulators is precisely matched to the intended speech outputs during future articulations.

The anatomy of language: a review of 100 fMRI studies published in 2009

In this review of 100 fMRI studies of speech comprehension and production, published in 2009, activation is reported for: prelexical speech perception in bilateral superior temporal gyri; meaningful speech in middle and inferior temporal cortex; semantic retrieval in the left angular gyrus and pars orbitalis; and sentence comprehension in bilateral superior temporal sulci. For incomprehensible sentences, activation increases in four inferior frontal regions, posterior planum temporale, and ventral supramarginal gyrus. These effects are associated with the use of prior knowledge of semantic associations, word sequences, and articulation that predict the content of the sentence. Speech production activates the same set of regions as speech comprehension but in addition, activation is reported for: word retrieval in left middle frontal cortex; articulatory planning in the left anterior insula; the initiation and execution of speech in left putamen, pre-SMA, SMA, and motor cortex; and for suppressing unintended responses in the anterior cingulate and bilateral head of caudate nuclei. Anatomical and functional connectivity studies are now required to identify the processing pathways that integrate these areas to support language.