The semantic interference effect in the picture-word paradigm: an event-related fMRI study employing overt responses

Neural Correlates of Semantic Interference and Phonological Facilitation in Picture Naming: A Systematic Review and Coordinate-Based Meta-analysis

Semantic interference (SI) and phonological facilitation (PF) effects occur when multiple representations are co-activated simultaneously in complex naming paradigms, manipulating the context in which word production is set. Although the behavioral consequences of these psycholinguistic effects are well-known, the involved brain structures are still controversial. This paper aims to provide a systematic review and a coordinate-based meta-analysis of the available functional neuroimaging studies investigating SI and PF in picture naming paradigms. The included studies were fMRI experiments on healthy subjects, employing paradigms in which co-activations of representations were obtained by manipulating the naming context using semantically or phonologically related items. We examined the principal methodological aspects of the included studies, emphasizing the existing commonalities and discrepancies across single investigations. We then performed an exploratory coordinate-based meta-analysis of the reported activation peaks of neural response related to SI and PF. Our results consolidated previous findings regarding the involvement of the left inferior frontal gyrus and the left middle temporal gyrus in SI and brought out the role of bilateral inferior parietal regions in PF.

On the evolution of polysensory superior temporal sulcus and middle temporal gyrus: A key component of the semantic system in the human brain

The primary auditory cortex and other early auditory cortical areas lie on Heschl's gyrus within the Sylvian fissure. On the adjacent lateral surface of the superior temporal gyrus, the cortex processes higher order auditory information leading to auditory perception. On the ventral surface of the temporal lobe in the primate brain, there are areas that process higher order visual information leading to visual perception. These sensory-specific auditory and visual processing regions are separated by areas that integrate multisensory information within the deep superior temporal sulcus in both the macaque monkey and human brains. In the human brain, the multisensory integration cortex expands and forms the adjacent middle temporal gyrus. The expansion of this multisensory region in the language-dominant hemisphere of the human brain is critical for the emergence of semantic processing, namely, the processing of conceptual information that is not sensory specific but rather relies on multisensory integration.

Clinical recommendations for conducting pediatric functional language and memory mapping during the phase I epilepsy presurgical workup

Objective: Pediatric epilepsy surgery effectively controls seizures but may risk cognitive, language, or memory decline. Historically, the intra-carotid anesthetic procedure (IAP or Wada Test) was pivotal for language and memory function. However, advancements in noninvasive mapping, notably functional magnetic resonance imaging (fMRI), have transformed clinical practice, reducing IAP's role in presurgical evaluations. Method: We conducted a critical narrative review on mapping technologies, including factors to consider for discordance. Results: Neuropsychological findings suggest that if pre-surgery function remains intact and the surgery targets the eloquent cortex, there is a high chance for decline. Memory and language decline are particularly pronounced post-left anterior temporal lobe resection (ATL), making presurgical cognitive assessment crucial for predicting postoperative outcomes. However, the risk of functional decline is not always clear - particularly with higher rates of atypical organization in pediatric epilepsy patients and discordant findings from cognitive mapping. We found little research to date on the use of IAP and other newer technologies for lateralization/localization in pediatric epilepsy. Based on this review, we introduce an IAP decision tree to systematically navigate discordance in IAP decisions for epilepsy presurgical workup. Conclusions: Future research should be aimed at pediatric populations to improve the precision of functional mapping, determine which methods predict post-surgical deficits and then create evidence-based practice guidelines to standardize mapping procedures. Explicit directives are needed for resolving conflicts between developing mapping procedures and established clinical measures. The proposed decision tree is the first step to standardize when to consider IAP or invasive mapping, in coordination with the multidisciplinary epilepsy surgical team.

Effects of Remote Expressive Arts Program in Older Adults with Mild Cognitive Impairment: A Randomized Controlled Trial

BACKGROUND

Mild cognitive impairment (MCI) is a stage of cognitive ability loss with intact activities of daily living and an increased risk for the development of dementia.

OBJECTIVE

This study evaluated the intervention effect of remote expressive arts program (rEAP) on cognitive function in older adults with MCI and investigated the underlying neurobiological mechanisms.

METHODS

We assigned 73 older MCI patients to receive rEAP or health education (HE), who underwent neuropsychological evaluation and resting-state functional magnetic resonance imaging before and after treatment. Neuropsychological scores were analyzed using SPSS software, and regional homogeneity (ReHo) values and seed-based functional connectivity (FC) were analyzed using Matlab software.

RESULTS

The rEAP group showed more significant improvements in cognitive function than the HE group. rEAP affected spontaneous brain activity and brain networks. The ReHo values in the right anterior cingulate/paracingulate cortex and the left dorsolateral superior frontal gyrus significantly increased and decreased, respectively, in the rEAP and HE groups. Further, ReHo value changes were significantly associated with the corresponding neuropsychological test score changes in the rEAP group. Moreover, the rEAP group showed decreased FC between the posterior cingulate cortex and the right middle temporal gyrus and increased FC between the ventromedial prefrontal cortex and left angular gyrus.

CONCLUSION

The 12-week rEAP improved cognitive function in MCI patients. Additionally, the alterations of spontaneous brain network connections and activity helped improve and maintain cognitive function in MCI patients.

Resisting Visual, Phonological, and Semantic Interference - Same or Different Processes? A Focused Mini-Review

The unitary nature of resistance to interference (RI) processes remains a strongly debated question: are they central cognitive processes or are they specific to the stimulus domains on which they operate? This focused mini-review examines behavioral, neuropsychological and neuroimaging evidence for and against domain-general RI processes, by distinguishing visual, verbal phonological and verbal semantic domains. Behavioral studies highlighted overall low associations between RI capacity across domains. Neuropsychological studies mainly report dissociations for RI abilities between the three domains. Neuroimaging studies highlight a left vs. right hemisphere distinction for verbal vs. visual RI, with furthermore distinct neural processes supporting phonological versus semantic RI in the left inferior frontal gyrus. While overall results appear to support the hypothesis of domain-specific RI processes, we discuss a number of methodological caveats that ask for caution in the interpretation of existing studies.

Word Production Changes through Adolescence: A Behavioral and ERP Investigation of Referential and Inferential Naming

Changes in word production occur across the lifespan, with adolescence representing a knot point between children's and adults' performance and underlying brain processes. Previous studies on referential word production using picture naming tasks have shown a completely adult-like pattern in 17-year-old adolescents and an intermediate pattern between children and adults in adolescents aged 14-16 years old, suggesting a possible involvement of visuo-conceptual processes in the transition from childhood to adulthood. Given the visual nature of the picture naming task, it is unclear whether changes in visuo-conceptual processes are specifically related to the referential word production or if overall changes in conceptual to lexical processes drive maturation. To answer this question, we turned to an inferential word production task, i.e., naming from auditory definitions, involving different conceptual to lexical processes relative to referential naming. Behavior and electroencephalographic Event-Related Potentials (ERP) in a (visual) referential word production task and an (auditory) inferential word production task were recorded and compared in three groups of adolescents (respectively, aged 10 to 13, 14 to 16, and 17 to 18). Only the youngest group displayed longer production latencies and lower accuracy than the two older groups of adolescents who performed similarly on both tasks. Crucially, ERP waveform analysis and topographic pattern analysis revealed significant intergroup differences on both tasks. Changes across ages are not merely linked to the visual-conceptual processes of a picture naming task but are rather related to lexical-semantic processes involved in word production.

Reinvestigating the Neural Bases Involved in Speech Production of Stutterers: An ALE Meta-Analysis

Background: Stuttering is characterized by dysfluency and difficulty in speech production. Previous research has found abnormalities in the neural function of various brain areas during speech production tasks. However, the cognitive neural mechanism of stuttering has still not been fully determined. Method: Activation likelihood estimation analysis was performed to provide neural imaging evidence on neural bases by reanalyzing published studies. Results: Our analysis revealed overactivation in the bilateral posterior superior temporal gyrus, inferior frontal gyrus, medial frontal gyrus, precentral gyrus, postcentral gyrus, basal ganglia, and cerebellum, and deactivation in the anterior superior temporal gyrus and middle temporal gyrus among the stutterers. The overactivated regions might indicate a greater demand in feedforward planning in speech production, while the deactivated regions might indicate dysfunction in the auditory feedback system among stutterers. Conclusions: Our findings provide updated and direct evidence on the multi-level impairment (feedforward and feedback systems) of stutterers during speech production and show that the corresponding neural bases were differentiated.

Neural sensitivity to semantic neighbors is stable across the adult lifespan

As we age, language reflects patterns of both stability and change. On the one hand, vocabulary and semantic abilities are largely stable across the adult lifespan, yet lexical retrieval is often slower and less successful (i.e., slower picture naming times, increased tip of the tongue incidents). Although the behavioral bases of these effects have been well established, less is known about the brain regions that support these age-related differences. We used functional Magnetic Resonance Imaging (fMRI) to examine the neural basis of picture naming. Specifically, we were interested in whether older adults would be equally sensitive to semantic characteristics, specifically the number of semantic near neighbors. Near neighbors, defined here as items with a high degree of semantic feature overlap, were of interest as these are thought to elicit competition among potential candidates and increase naming difficulty. Consistent with prior reports, pictures with more semantic near neighbors were named more slowly and less accurately for all adults. Additionally, this interference for naming times was larger as age increased, starting around 30 years old. In contrast to the age-related behavioral slowing, the neural basis of these effects was stable across adulthood. Across all adults, a number of language-relevant regions including left posterior middle temporal gyrus and left inferior frontal gyrus, pars triangularis were sensitive to the number of near neighbors. Our results suggest that although middle-aged and older adults' picture naming is more slowed by increased semantic competition, the brain regions supporting semantic processes remain stable across the adult lifespan.

The Neuroanatomy of Speech Processing: A Large-scale Lesion Study

The neural basis of language has been studied for centuries, yet the networks critically involved in simply identifying or understanding a spoken word remain elusive. Several functional-anatomical models of critical neural substrates of receptive speech have been proposed, including (1) auditory-related regions in the left mid-posterior superior temporal lobe, (2) motor-related regions in the left frontal lobe (in normal and/or noisy conditions), (3) the left anterior superior temporal lobe, or (4) bilateral mid-posterior superior temporal areas. One difficulty in comparing these models is that they often focus on different aspects of the sound-to-meaning pathway and are supported by different types of stimuli and tasks. Two auditory tasks that are typically used in separate studies-syllable discrimination and word comprehension-often yield different conclusions. We assessed syllable discrimination (words and nonwords) and word comprehension (clear speech and with a noise masker) in 158 individuals with focal brain damage: left (n = 113) or right (n = 19) hemisphere stroke, left (n = 18) or right (n = 8) anterior temporal lobectomy, and 26 neurologically intact controls. Discrimination and comprehension tasks are doubly dissociable both behaviorally and neurologically. In support of a bilateral model, clear speech comprehension was near ceiling in 95% of left stroke cases and right temporal damage impaired syllable discrimination. Lesion-symptom mapping analyses for the syllable discrimination and noisy word comprehension tasks each implicated most of the left superior temporal gyrus. Comprehension but not discrimination tasks also implicated the left posterior middle temporal gyrus, whereas discrimination but not comprehension tasks also implicated more dorsal sensorimotor regions in posterior perisylvian cortex.

Animacy-induced conflict in sentence production and comprehension from late childhood to adolescence

Some animacy configurations elicit parallel semantic interference in adult production and comprehension; for example, phrases with similar animate nouns like the man that the girl is hugging are more difficult than phrases like the doll that the girl is hugging. Yet little is known about how this interference manifests in development, particularly, beyond early childhood. Because frontal brain maturation and cognitive control improvements are known to occur across late childhood and adolescence, we investigated (a) how animacy-induced difficulty in production and comprehension vary with age throughout this period and (b) whether control processes reflected in the backward digit span (BDS) test uniquely explained these differences besides other language measures. In separate tasks, participants (8- to 15-year-old children; N = 91) heard auditory descriptions of depicted characters, produced characters' descriptions, and completed BDS, vocabulary, and reading experience tests. Results indicated that, as in adults, animacy modulated performance in production and comprehension across all ages. The animacy modulation interacted with age in production but not in comprehension, suggesting age-related animacy differences in production but relatively stable differences in comprehension despite processing speed improvements. Importantly, these age-related production differences were also modulated by the BDS scores; only participants with higher BDS scores displayed age-related animacy differences. Together, these results indicate that comprehension and production develop at different rates and that the development of BDS performance interacts with age-dependent changes in sentence planning from late childhood to adolescence. More generally, the study highlights tasks' disparities to be explained by cognitive and developmental models of language.

Functional Connectivity as a Potential Mechanism for Language Plasticity

BACKGROUND AND OBJECTIVES

Task fMRI is a clinical tool for language lateralization, but has limitations, and cannot provide information about network-level plasticity. Additional methods are needed to improve the precision of presurgical language mapping. We investigate language resting-state functional connectivity (RS fMRI; FC) in typically developing children (TD) and children with epilepsy. Our objectives were to (1) understand how FC components differ between TD children and those with epilepsy; (2) elucidate how the location of disease (frontal/temporal epilepsy foci) affects FC; and (3) investigate the relationship between age and FC.

METHODS

Our sample included 55 TD children (mean age 12 years, range 7-18) and 31 patients with focal epilepsy (mean age 13 years, range 7-18). All participants underwent RS fMRI. Using a bilateral canonical language map as target, vertex-wise intrahemispheric FC map and interhemispheric FC map for each participant were computed and thresholded at top 10% to compute an FC laterality index (FCLI; [(L - R)/(L + R)]) of the frontal and temporal regions for both integration (intrahemispheric FC; FCLIi) and segregation (interhemispheric FC; FCLIs) maps.

RESULTS

We found FC differences in the developing language network based on disease, seizure foci location, and age. Frontal and temporal FCLIi was different between groups (t[84] = 2.82, p < 0.01; t[84] = 4.68, p < 0.01, respectively). Frontal epilepsy foci had the largest differences from TD (Cohen d frontal FCLIi = 0.84, FCLIs = 0.51; temporal FCLIi = 1.29). Development and disease have opposing influences on the laterality of FC based on groups. In the frontal foci group, FCLIi decreased with age (r = -0.42), whereas in the temporal foci group, FCLIi increased with age (r = 0.40). Within the epilepsy group, increases in right frontal integration FCLI relates to increased right frontal task activation in our mostly left language dominant group (r = 0.52, p < 0.01). Language network connectivity is associated with higher verbal intelligence in children with epilepsy (r = 0.45, p < 0.05).

DISCUSSION

These findings lend preliminary evidence that FC reflects network plasticity in the form of adaptation and compensation, or the ability to recruit support and reallocate resources within and outside of the traditional network to compensate for disease. FC expands on task-based fMRI and provides complementary and potentially useful information about the language network that is not captured using task-based fMRI alone.

BONEs not CATs attract DOGs: Semantic context effects for picture naming in the lesioned language network

The breakdown of rapid and accurate retrieval of words is a hallmark of aphasic speech and a prime target of therapeutic intervention. Complementary, psycho- and neurolinguistic research have developed a spectrum of models, how and by which neuronal network uncompromised speakers can rely on remarkable lexical retrieval capacities. Motivated by both lines of research we invited 32 participants with a chronic left hemispheric brain lesion to name pictures in the presence of distractor words. This picture-word-interference (PWI) paradigm is widely used in psycho- and neurolinguistic research. We find that also after brain lesion categorically related words (CAT → [dog]^picture) impede naming, while associatively related words (BONE → [dog]^picture) ease access, when compared to unrelated distractor words. The effects largely affecting latencies in neurotypical populations, are reproduced for error rate in our participants with lesions in the language network. Unsurprisingly, overall naming abilities varied greatly across patients. Notably, however, the two effects (categorical interference / associative facilitation) differ between participants. Correlating performance with lesion patterns we find support for the notion of a divergence of brain areas affording different aspects of the task: (i) lesions in the left middle temporal gyurs (MTG) deteriorate overall naming, confirming previous work; more notably, (ii) lesions comprising the inferior frontal hub (inferior frontal gyrus, IFG) of the language-network increase the interference effect for the categorical condition; on the contrary, (iii) lesions to the mid-to-posterior temporal hub (posterior middle and superior temporal gyri, pMTG/ pSTG) increase the facilitatory effect for the associative condition on error rates. The findings can be accommodated in a neuro-linguistic framework, which localizes lexical activation but also lexical interference in posterior parts of the language network (pMTG/pITG); conversely, selection between co-activated categorically related entries is afforded by frontal language areas (IFG). While purely experimental in nature our study highlights that lesion site differentially influences specific aspects of word retrieval. Since confrontational naming is a cornerstone of aphasia rehabilitation, this may be of note when designing and evaluating novel therapeutic regimes.

Adaptation of a semantic picture-word interference paradigm for future language mapping with transcranial magnetic stimulation: A behavioural study

Neuro-navigated transcranial magnetic stimulation (TMS) helps to identify language-related cortical regions prior to brain tumour surgery. We adapted a semantic picture-word interference (PWI) paradigm from psycholinguistics to high-resolution TMS language mapping which prospectively can be used to specifically address the level of semantic processing. In PWI, pictures are presented along with distractor words which facilitate or inhibit the lexical access to the picture name. These modulatory effects of distractors can be annihilated in language-sensitive areas by the inhibitory effects of TMS on language processing. The rationale here is to observe the distractor effect without active stimulation and then to observe presumably its elimination by interference of the TMS stimulation. The special requirements to use PWI in this setting are (1) identifying word material for accelerating reliably naming latencies, choosing (2) the ideal presentation modality, and (3) the appropriate timing of distractor presentation. These are then controlled in real TMS language mapping. To adapt a semantic PWI naming paradigm for TMS application we employed 30 object-pictures in spoken German language. Part-whole associative semantic related or unrelated distractors were presented in two experiments including 15 healthy volunteers each, once auditorily and once visually. Data analysis across the entire stimulus set revealed a trend for facilitation in the visual condition, whereas no effects were observed for auditory distractors. In a sub-set, we found a significant facilitation effect for visual semantic distractors. Thus, with this study we provide a well-controlled item set for future studies implementing effective TMS language mapping applying visual semantic PWI.

Cerebellar and Cortical Correlates of Internal and External Speech Error Monitoring

An event-related functional magnetic resonance imaging study examined how speakers inspect their own speech for errors. Concretely, we sought to assess 1) the role of the temporal cortex in monitoring speech errors, linked with comprehension-based monitoring; 2) the involvement of the cerebellum in internal and external monitoring, linked with forward modeling; and 3) the role of the medial frontal cortex for internal monitoring, linked with conflict-based monitoring. In a word production task priming speech errors, we observed enhanced involvement of the right posterior cerebellum for trials that were correct, but on which participants were more likely to make a word as compared with a nonword error (contrast of internal monitoring). Furthermore, comparing errors to correct utterances (contrast of external monitoring), we observed increased activation of the same cerebellar region, of the superior medial cerebellum, and of regions in temporal and medial frontal cortex. The presence of the cerebellum for both internal and external monitoring indicates the use of forward modeling across the planning and articulation of speech. Dissociations across internal and external monitoring in temporal and medial frontal cortex indicate that monitoring of overt errors is more reliant on vocal feedback control.

Similar activation patterns in the bilateral dorsal inferior frontal gyrus for monolingual and bilingual contexts in second language production

Language production is a vital process of communication. Although many studies have devoted to the neural mechanisms of language production in bilinguals, they mainly focused on the mechanisms of cognitive control during language switching. Therefore, it is not clear how naming context influences the neural representations of linguistic information during language production in bilinguals. To address that question, the present study adopted representational similarity analysis (RSA) to investigate the neural pattern similarity (PS) between the monolingual and bilingual contexts separately for native and second languages. Consistent with previous findings, bilinguals behaviorally performed worse, and showed greater activation in brain regions for cognitive control including the anterior cingulate cortex and dorsolateral prefrontal cortex in the bilingual context relative to the monolingual context. More importantly, RSA revealed that bilinguals exhibited similar neural activation patterns in the bilateral dorsal inferior frontal gyrus between the monolingual and bilingual contexts in the production of the second language. Moreover, higher cross-context PS in the right inferior frontal gyrus was associated with smaller differences in naming speed of second language between the monolingual and bilingual contexts. These results suggest that similar linguistic representations are encoded for the monolingual and bilingual contexts in the production of non-dominant language.

The Dynamics of Speech Motor Control Revealed with Time-Resolved fMRI

Holding a conversation means that speech must be started, maintained, and stopped continuously. The brain networks that underlie these aspects of speech motor control remain poorly understood. Here we collected functional magnetic resonance imaging (fMRI) data while participants produced normal and fast rate speech in response to sequences of visually presented objects. We took a non-conventional approach to fMRI data analysis that allowed us to study speech motor behavior as it unfolded over time. To this end, whole-brain fMRI signals were extracted in stimulus-locked epochs using slice-based fMRI. These data were then subjected to group independent component analysis to discover spatially independent networks that were associated with different temporal activation profiles. The results revealed two basic brain networks with different temporal dynamics: a cortical network that was activated continuously during speech production, and a second cortico-subcortical network that increased in activity during the initiation and suppression of speech production. Additional analyses explored whether key areas involved in motor suppression such as the right inferior frontal gyrus, sub-thalamic nucleus and pre-supplementary motor area provide first-order signals to stop speech. The results reveal for the first time the brain networks associated with the initiation, maintenance, and suppression of speech motor behavior.

Morphological facilitation and semantic interference in compound production: An ERP study

This study investigates the production of nominal compounds (Experiment 1) and simple nouns (Experiment 2) in a picture-word interference (PWI) paradigm to test models of morpho-lexical representation and processing. The continuous electroencephalogram (EEG) was registered and event-related brain potentials [ERPs] were analyzed in addition to picture-naming latencies. Experiment 1 used morphologically and semantically related distractor words to tap into different pre-articulatory planning stages during compound production. Relative to unrelated distractors, naming was speeded when distractors corresponded to morphemes of the compound (sun or flower for the target sunflower), but slowed when distractors were from the same semantic category as the compound (tulip ➔ sunflower). Distractors from the same category as the compound's first constituent (moon ➔ sunflower) had no influence. The diverging effects for semantic and morphological distractors replicate results from earlier studies. ERPs revealed different effects of morphological and semantic distractors with an interesting time course: morphological effects had an earlier onset. Comparable to the naming latencies, no ERP effects were obtained for distractors from the same semantic category as the compound's first constituent. Experiment 2 investigated the effectiveness of the latter distractors, presenting them with pictures of the compounds' first constituents (e.g., moon ➔ sun). Interference was confirmed both behaviorally and in the ERPs, showing that the absence of an effect in Experiment 1 was not due to the materials used. Considering current models of speech production, the data are best explained by a cascading flow of activation throughout semantic, lexical and morpho-phonological steps of speech planning.

Neuro-Clinical Signatures of Language Impairments: A Theoretical Framework for Function-to-structure Mapping in Clinics

In the past decades, neuroscientists and clinicians have collected a considerable amount of data and drastically increased our knowledge about the mapping of language in the brain. The emerging picture from the accumulated knowledge is that there are complex and combinatorial relationships between language functions and anatomical brain regions. Understanding the underlying principles of this complex mapping is of paramount importance for the identification of the brain signature of language and Neuro-Clinical signatures that explain language impairments and predict language recovery after stroke. We review recent attempts to addresses this question of language-brain mapping. We introduce the different concepts of mapping (from diffeomorphic one-to-one mapping to many-to-many mapping). We build those different forms of mapping to derive a theoretical framework where the current principles of brain architectures including redundancy, degeneracy, pluri-potentiality and bow-tie network are described.

Language proficiency moderates the effect of L2 semantically related distractors in L2 spoken word production

Bilinguals differ substantially in their second language (L2) proficiency, but it remains unclear whether language proficiency modulates the effect of L2 semantically related distractors in L2 spoken word production. In the present study, two groups of high proficiency and low proficiency Chinese-English bilinguals named target pictures in their L2 accompanied by visually superimposed L2 distractor words while electroencephalogram signals were recorded. Distractor names were semantically related or unrelated to target names. Variables of L2 proficiency (high proficiency or low proficiency) and semantic relatedness (related or unrelated) were manipulated in the experiment. Behavioral results demonstrated an interaction between L2 proficiency and semantic relatedness, with a semantic interference effect appearing only in high proficiency bilinguals. Waveform analysis indicated that semantic relatedness only exerted significant effects on event-related potentials in high proficiency bilinguals around 300-500 ms post picture presentation. Source localization analysis revealed that semantically related distractors induced higher brain activations in the left middle and superior temporal regions among high proficiency bilinguals, while higher brain activations were found in the right prefrontal cortex among low proficiency bilinguals. Taken together, these findings substantiate the role of language proficiency in determining whether L2 semantically related distractors are sufficiently activated to exceed the competition threshold and interfere with L2 picture naming.

Inhibitory Control of Lexical Selection in Adults who Stutter

PURPOSE

Based on previous evidence that lexical selection may operate differently in adults who stutter (AWS) versus typically-fluent adults (TFA), and that atypical attentional processing may be a contributing factor, the purpose of this study was to investigate inhibitory control of lexical selection in AWS.

METHOD

12 AWS and 12 TFA completed two tasks. One was a picture naming task featuring High and Low Agreement object naming. Naming accuracy and reaction times (RT), and event-related potentials (ERPs) time-locked to picture onset, were recorded. Second was a flanker task featuring Congruent and Incongruent arrow arrays. Push-button accuracy and RTs, and ERPs time-locked to arrow array onset, were recorded.

RESULTS

Low Agreement pictures were named less accurately and slower than High Agreement pictures in both Groups. The magnitude of the Agreement effect on naming RTs was larger in AWS versus TFA. Delta-plot analysis revealed that the Agreement effect was positively correlated with individual differences in inhibition in TFA but not in AWS. Moreover, Low Agreement pictures elicited negative-going ERP activity relative to High Agreement pictures in both Groups. However, the scalp topography of this effect was markedly reduced in AWS versus TFA. For the Flanker task, Congruency affected push-button accuracy and RTs, and N2 amplitudes, similarly between groups.

CONCLUSIONS

Results point to a selective deficit in inhibitory control of lexical selection in AWS. Potential pathways between diminished inhibitory control of lexical selection, speech motor control and stuttering are discussed.

How the speed of word finding depends on ventral tract integrity in primary progressive aphasia

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Noise words influence naming time, but not accuracy, more in PPA than in controls.

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Noise effect difference between PPA and controls reflects ventral tract integrity.

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The noise effect is smaller when ventral tract integrity is lower in the individuals with PPA.

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Simulations reveal that propagation of noise is reduced when tract integrity is low.

Primary progressive aphasia (PPA) is a clinical neurodegenerative syndrome with word finding problems as a core clinical symptom. Many aspects of word finding have been clarified in psycholinguistics using picture naming and a picture-word interference (PWI) paradigm, which emulates naming under contextual noise. However, little is known about how word finding depends on white-matter tract integrity, in particular, the atrophy of tracts located ventrally to the Sylvian fissure. To elucidate this question, we examined word finding in individuals with PPA and healthy controls employing PWI, tractography, and computer simulations using the WEAVER++ model of word finding. Twenty-three individuals with PPA and twenty healthy controls named pictures in two noise conditions. Mixed-effects modelling was performed on naming accuracy and reaction time (RT) and fixel-based tractography analyses were conducted to assess the relation between ventral white-matter integrity and naming performance. Naming RTs were longer for individuals with PPA compared to controls and, critically, individuals with PPA showed a larger noise effect compared to controls. Moreover, this difference in noise effect was differentially related to tract integrity. Whereas the noise effect did not depend much on tract integrity in controls, a lower tract integrity was related to a smaller noise effect in individuals with PPA. Computer simulations supported an explanation of this paradoxical finding in terms of reduced propagation of noise when tract integrity is low. By using multimodal analyses, our study indicates the significance of the ventral pathway for naming and the importance of RT measurement in the clinical assessment of PPA.

Towards a New Model of Verbal Monitoring

As all human activities, verbal communication is fraught with errors. It is estimated that humans produce around 16,000 words per day, but the word that is selected for production is not always correct and neither is the articulation always flawless. However, to facilitate communication, it is important to limit the number of errors. This is accomplished via the verbal monitoring mechanism. A body of research over the last century has uncovered a number of properties of the mechanisms at work during verbal monitoring. Over a dozen routes for verbal monitoring have been postulated. However, to date a complete account of verbal monitoring does not exist. In the current paper we first outline the properties of verbal monitoring that have been empirically demonstrated. This is followed by a discussion of current verbal monitoring models: the perceptual loop theory, conflict monitoring, the hierarchical state feedback control model, and the forward model theory. Each of these models is evaluated given empirical findings and theoretical considerations. We then outline lacunae of current theories, which we address with a proposal for a new model of verbal monitoring for production and perception, based on conflict monitoring models. Additionally, this novel model suggests a mechanism of how a detected error leads to a correction. The error resolution mechanism proposed in our new model is then tested in a computational model. Finally, we outline the advances and predictions of the model.

Age-related differences in the neural bases of phonological and semantic processes in the context of task-irrelevant information

As we age we have increasing difficulty with phonological aspects of language production. Yet semantic processes are largely stable across the life span. This suggests a fundamental difference in the cognitive and potentially neural architecture supporting these systems. Moreover, language processes such as these interact with other cognitive processes that also show age-related decline, such as executive function and inhibition. The present study examined phonological and semantic processes in the presence of task-irrelevant information to examine the influence of such material on language production. Older and younger adults made phonological and semantic decisions about pictures in the presence of either phonologically or semantically related words, which were unrelated to the task. FMRI activation during the semantic condition showed that all adults engaged typical left-hemisphere language regions, and that this activation was positively correlated with efficiency across all adults. In contrast, the phonological condition elicited activation in bilateral precuneus and cingulate, with no clear brain-behavior relationship. Similarly, older adults exhibited greater activation than younger adults in several regions that were unrelated to behavioral performance. Our results suggest that as we age, brain-behavior relations decline, and there is an increased reliance on both language-specific and domain-general brain regions that are seen most prominently during phonological processing. In contrast, the core semantic system continues to be engaged throughout the life span, even in the presence of task-irrelevant information.

Brain Activation During Conceptual Processing of Action and Sound Verbs

Grounded cognition approaches to conceptual representations postulate a close link between conceptual knowledge and the sensorimotor brain systems. The present fMRI study tested, whether a feature-specific representation of concepts, as previously demonstrated for nouns, can also be found for action- and sound-related verbs. Participants were presented with action- and soundrelated verbs along with pseudoverbs while performing a lexical decision task. Sound-related verbs activated auditory areas in the temporal cortex, whereas action-related verbs activated brain regions in the superior frontal gyrus and the cerebellum, albeit only at a more liberal threshold. This differential brain activation during conceptual verb processing partially overlapped with or was adjacent to brain regions activated during the functional localizers probing sound perception or action execution. Activity in brain areas involved in the processing of action information was parametrically modulated by ratings of action relevance. Comparisons of action- and sound-related verbs with pseudoverbs revealed activation for both verb categories in auditory and motor areas. In contrast to proposals of strong grounded cognition approaches, our study did not demonstrate a considerable overlap of activations for action- and sound-related verbs and for the corresponding functional localizer tasks. However, in line with weaker variants of grounded cognition theories, the differential activation pattern for action- and sound-related verbs was near corresponding sensorimotor brain regions depending on conceptual feature relevance. Possibly, action-sound coupling resulted in a mutual activation of the motor and the auditory system for both action- and sound-related verbs, thereby reducing the effect sizes for the differential contrasts.

The Brain Differentially Prepares Inner and Overt Speech Production: Electrophysiological and Vascular Evidence

Speech production not only relies on spoken (overt speech) but also on silent output (inner speech). Little is known about whether inner and overt speech are processed differently and which neural mechanisms are involved. By simultaneously applying electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS), we tried to disentangle executive control from motor and linguistic processes. A preparation phase was introduced additionally to the examination of overt and inner speech directly during naming (i.e., speech execution). Participants completed a picture-naming paradigm in which the pure preparation phase of a subsequent speech production and the actual speech execution phase could be differentiated. fNIRS results revealed a larger activation for overt rather than inner speech at bilateral prefrontal to parietal regions during the preparation and at bilateral temporal regions during the execution phase. EEG results showed a larger negativity for inner compared to overt speech between 200 and 500 ms during the preparation phase and between 300 and 500 ms during the execution phase. Findings of the preparation phase indicated that differences between inner and overt speech are not exclusively driven by specific linguistic and motor processes but also impacted by inhibitory mechanisms. Results of the execution phase suggest that inhibitory processes operate during phonological code retrieval and encoding.

Brain response to food brands correlates with increased intake from branded meals in children: an fMRI study

Food branding is ubiquitous, however, not all children are equally susceptible to its effects. The objectives of this study were to 1) determine whether food brands evoke differential response than non-food brands in brain areas related to motivation and inhibitory control using blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) and 2) determine the association between brain response and energy intake at test-meals presented with or without brands. Twenty-eight 7-10 year-old children completed four visits as part of a within-subjects design where they consumed three multi-item test-meals presented with familiar food brands, novel food brand, and no brand. On the fourth visit an fMRI was performed where children passively viewed food brands, non-food brands and control images. A whole-brain analysis was conducted to compare BOLD response between conditions. Pearson's correlations were calculated to determine the association between brain response and meal intake. Relative to non-food brands, food brand images were associated with increased activity in the right lingual gyrus. Relative to control, food and non-food brand images were associated with greater response in bilateral fusiform gyri and decreased response in the cuneus, precuneus, lingual gyrus, and supramarginal gyrus. Less activation in the bilateral fusiform gyrus to both food and non-food brands was associated with greater energy intake of the branded vs unbranded meal. These findings may help explain differences in the susceptibility to the intake-promoting effects of food advertising in children.

Neural correlates of positive and negative symptoms through the illness course: an fMRI study in early psychosis and chronic schizophrenia

Psychotic illness is associated with cognitive control deficits and abnormal recruitment of neural circuits subserving cognitive control. It is unclear to what extent this dysfunction underlies the development and/or maintenance of positive and negative symptoms typically observed in schizophrenia. In this study we compared fMRI activation on a standard Stroop task and its relationship with positive and negative symptoms in early psychosis (EP, N = 88) and chronic schizophrenia (CHR-SZ, N = 38) patients. CHR-SZ patients showed reduced frontal, striatal, and parietal activation across incongruent and congruent trials compared to EP patients. Higher positive symptom severity was associated with reduced activation across both trial types in supplementary motor area (SMA), middle temporal gyrus and cerebellum in EP, but not CHR-SZ patients. Higher negative symptom severity was associated with reduced cerebellar activation in EP, but not in CHR-SZ patients. A negative correlation between negative symptoms and activation in SMA and precentral gyrus was observed in EP patients and in CHR-SZ patients. The results suggest that the neural substrate of positive symptoms changes with illness chronicity, and that cognitive control related neural circuits may be most relevant in the initial development phase of positive symptoms. These findings also highlight a changing role for the cerebellum in the development and later maintenance of both positive and negative symptoms.

Neural Mechanisms for Monitoring and Halting of Spoken Word Production

During conversation, speakers monitor their own and others' output so they can alter their production adaptively, including halting it if needed. We investigated the neural mechanisms of monitoring and halting in spoken word production by employing a modified stop signal task during fMRI. Healthy participants named target pictures and withheld their naming response when presented with infrequent auditory words as stop signals. We also investigated whether the speech comprehension system monitors inner (i.e., prearticulatory) speech via the output of phonological word form encoding as proposed by the perceptual loop theory [Levelt, W. J. M. Speaking: From intention to articulation. Cambridge, MA: MIT Press, 1989] by presenting stop signals phonologically similar to the target picture name (e.g., cabbage-CAMEL). The contrast of successful halting versus naming revealed extensive BOLD signal responses in bilateral inferior frontal gyrus, preSMA, and superior temporal gyrus. Successful versus unsuccessful halting of speech was associated with increased BOLD signal bilaterally in the posterior middle temporal, frontal, and parietal lobes and decreases bilaterally in the posterior and left anterior superior temporal gyrus and right inferior frontal gyrus. These results show, for the first time, the neural mechanisms engaged during both monitoring and interrupting speech production. However, we failed to observe any differential effects of phonological similarity in either the behavioral or neural data, indicating monitoring of inner versus external speech might involve different mechanisms.

Task difficulty modulates brain-behavior correlations in language production and cognitive control: Behavioral and fMRI evidence from a phonological go/no-go picture-naming paradigm

Language production and cognitive control are complex processes that involve distinct yet interacting brain networks. However, the extent to which these processes interact and their neural bases have not been thoroughly examined. Here, we investigated the neural and behavioral bases of language production and cognitive control via a phonological go/no-go picture-naming task. Naming difficulty and cognitive control demands (i.e., conflict monitoring and response inhibition) were manipulated by varying the proportion of naming trials (go trials) and inhibition trials (no-go trials) across task runs. The results demonstrated that as task demands increased, participants' behavioral performance declined (i.e., longer reaction times on naming trials, more commission errors on inhibition trials) whereas brain activation generally increased. Increased activation was found not only within the language network but also in domain-general control regions. Additionally, right superior and inferior frontal and left supramarginal gyri were sensitive to increased task difficulty during both language production and response inhibition. We also found both positive and negative brain-behavior correlations. Most notably, increased activation in sensorimotor regions, such as precentral and postcentral gyri, was associated with better behavioral performance, in both successful picture naming and successful inhibition. Moreover, comparing the strength of correlations across conditions indicated that the brain-behavior correlations in sensorimotor regions that were associated with improved performance became stronger as task demands increased. Overall, our results suggest that cognitive control demands affect language production, and that successfully coping with increases in task difficulty relies on both language-specific and domain-general cognitive control regions.

Aberrant activity in conceptual networks underlies N400 deficits and unusual thoughts in schizophrenia

Background

The N400 event-related potential (ERP) is triggered by meaningful stimuli that are incongruous, or unmatched, with their semantic context. Functional magnetic resonance imaging (fMRI) studies have identified brain regions activated by semantic incongruity, but their precise links to the N400 ERP are unclear. In schizophrenia (SZ), N400 amplitude reduction is thought to reflect overly broad associations in semantic networks, but the abnormalities in brain networks underlying deficient N400 remain unknown. We utilized joint independent component analysis (JICA) to link temporal patterns in ERPs to neuroanatomical patterns from fMRI and investigate relationships between N400 amplitude and neuroanatomical activation in SZ patients and healthy controls (HC).

Methods

SZ patients (n = 24) and HC participants (n = 25) performed a picture-word matching task, in which words were either matched (APPLE→apple) by preceding pictures, or were unmatched by semantically related (in-category; IC, APPLE→lemon) or unrelated (out of category; OC, APPLE→cow) pictures, in separate ERP and fMRI sessions. A JICA “data fusion” analysis was conducted to identify the fMRI brain regions specifically associated with the ERP N400 component. SZ and HC loading weights were compared and correlations with clinical symptoms were assessed.

Results

JICA identified an ERP-fMRI “fused” component that captured the N400, with loading weights that were reduced in SZ. The JICA map for the IC condition showed peaks of activation in the cingulate, precuneus, bilateral temporal poles and cerebellum, whereas the JICA map from the OC condition was linked primarily to visual cortical activation and the left temporal pole. Among SZ patients, fMRI activity from the IC condition was inversely correlated with unusual thought content.

Conclusions

The neural networks associated with the N400 ERP response to semantic violations depends on conceptual relatedness. These findings are consistent with a distributed network underlying neural responses to semantic incongruity including unimodal visual areas as well as integrative, transmodal areas. Unusual thoughts in SZ may reflect impaired processing in transmodal hub regions such as the precuneus, leading to overly broad semantic associations.

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Hemodynamic activity linked to N400 responses is distributed across the brain.

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N400 linked networks depend on conceptual relatedness.

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Magnitude of the N400 ERP-fMRI fused component is reduced in schizophrenia.

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N400 linked network activity inversely correlates with unusual thought content.

Interference during the retrieval of arithmetic and lexico-semantic knowledge modulates similar brain regions: Evidence from functional magnetic resonance imaging (fMRI)

Single-digit multiplications are mainly solved by memory retrieval. However, these problems are also prone to errors due to systematic interference (i.e., co-activation of interconnected but incorrect solutions). Semantic control processes are crucial to overcome this type of interference and to retrieve the correct information. Previous research suggests the importance of several brain regions such as the left inferior frontal cortex and the intraparietal sulcus (IPS) for semantic control. But, this evidence is mainly based on tasks measuring interference during the processing of lexico-semantic information (e.g., pictures or words). Here, we investigated whether semantic control during arithmetic problem solving (i.e., multiplication fact retrieval) draws upon similar or different brain mechanisms as in other semantic domains (i.e., lexico-semantic). The brain activity of 46 students was measured with fMRI while participants performed an operand-related-lure (OR) and a picture-word (PW) task. In the OR task participants had to verify the correctness of a given solution to a single-digit multiplication. Similarly, in the PW task, participants had to judge whether a presented word matches the concept displayed in a picture or not. Analyses showed that resolving interference in these two tasks modulates the activation of a widespread fronto-parietal network (e.g., left/right IFG, left insula lobe, left IPS). Importantly, conjunction analysis revealed a neural overlap in the left inferior frontal gyrus (IFG) pars triangularis and left IPS. Additional Bayesian analyses showed that regions that are thought to store lexico-semantic information (e.g., left middle temporal gyrus) did not show evidence for an arithmetic interference effect. Overall, our findings not only indicate that semantic control plays an important role in arithmetic problem solving but also that it is supported by common brain regions across semantic domains. Additionally, by conducting Bayesian analysis we confirmed the hypothesis that the semantic control network contributes differently to semantic tasks of various domains.

Cortical Dynamics of Semantic Priming and Interference during Word Production: An Intracerebral Study

Language production requires that semantic representations are mapped to lexical representations on the basis of the ongoing context to select the appropriate words. This mapping is thought to generate two opposing phenomena, “semantic priming,” where multiple word candidates are activated, and “interference,” where these word activities are differentiated to make a goal-relevant selection. In previous neuroimaging and neurophysiological research, priming and interference have been associated to activity in regions of a left frontotemporal network. Most of such studies relied on recordings that either have high temporal or high spatial resolution, but not both. Here, we employed intracerebral EEG techniques to explore with both high resolutions, the neural activity associated with these phenomena. The data came from nine epileptic patients who were stereotactically implanted for presurgical diagnostics. They performed a cyclic picture-naming task contrasting semantically homogeneous and heterogeneous contexts. Of the 84 brain regions sampled, 39 showed task-evoked activity that was significant and consistent across two patients or more. In nine of these regions, activity was significantly modulated by the semantic manipulation. It was reduced for semantically homogeneous contexts (i.e., priming) in eight of these regions, located in the temporal ventral pathway as well as frontal areas. Conversely, it was increased only in the pre-SMA, notably at an early poststimulus temporal window (200–300 msec) and a preresponse temporal window (700–800 msec). These temporal effects respectively suggest the pre-SMA's role in initial conflict detection (e.g., increased response caution) and in preresponse control. Such roles of the pre-SMA are traditional from a history of neural evidence in simple perceptual tasks, yet are also consistent with recent cognitive lexicosemantic theories that highlight top–down processes in language production. Finally, although no significant semantic modulation was found in the ACC, future intracerebral EEG work should continue to inspect ACC with the pre-SMA.

Roles of ventral versus dorsal pathways in language production: An awake language mapping study

Human language is organized along two main processing streams connecting posterior temporal cortex and inferior frontal cortex in the left hemisphere, travelling dorsal and ventral to the Sylvian fissure. Some views propose a dorsal motor versus ventral semantic division. Others propose division by combinatorial mechanism, with the dorsal stream responsible for combining elements into a sequence and the ventral stream for forming semantic dependencies independent of sequential order. We acquired data from direct cortical stimulation in the left hemisphere in 17 neurosurgical patients and subcortical resection in a subset of 10 patients as part of awake language mapping. Two language tasks were employed: a sentence generation (SG) task tested the ability to form sequential and semantic dependencies, and a picture-word interference (PWI) task manipulated semantic interference. Results show increased error rates in the SG versus PWI task during subcortical testing in the dorsal stream territory, and high error rates in both tasks in the ventral stream territory. Connectivity maps derived from diffusion imaging and seeded in the tumor sites show that patients with more errors in the SG than in the PWI task had tumor locations associated with a dorsal stream connectivity pattern. Patients with the opposite pattern of results had tumor locations associated with a more ventral stream connectivity pattern. These findings provide initial evidence using fiber tract disruption with electrical stimulation that the dorsal pathways are critical for organizing words in a sequence necessary for sentence generation, and the ventral pathways are critical for processing semantic dependencies.

Task difficulty modulates age-related differences in the behavioral and neural bases of language production

Older adults typically show decline in a variety of cognitive functions including inhibitory control and language production, with corresponding age-related increases in fMRI activation. However, it remains unclear whether such increases are compensatory or whether they reflect neural decline. One factor that may influence these brain-behavior relationships is difficulty. The current study investigated the effect of difficulty on age-related differences in the behavioral and neural bases of language production and inhibitory control using a phonological Go/No-Go picture naming task. Task demands were manipulated by varying the proportion of naming trials (Go trials) and inhibition trials (No-Go trials) across runs. All participants showed task-difficulty related declines in behavioral performance and increases in fMRI activation. Behaviorally, older adults were more sensitive to task difficulty, and elicited more fMRI activation than younger adults. Older adults were less neurally responsive to additional task demands (i.e., picture naming alone vs. Go/No-Go picture naming), but interestingly showed similar within-task increases as younger adults (e.g., Go Bias vs. No-Go Bias). Moreover, the relationships between fMRI activation and behavioral performance in older adults were multifaceted and the strength of these relations changed as a function of task difficulty. Specifically, activation in pre- and post- central gyri, right supramarginal and angular gyri was negatively correlated with naming reaction times, suggesting that activation in these regions may help mitigate age-related declines in language production. These findings are partially consistent with the CRUNCH model, highlighting the important influence of task difficulty on older adults' behavioral performance and their patterns of fMRI activation during language production.

The Shape of Things to Come in Speech Production: A Functional Magnetic Resonance Imaging Study of Visual Form Interference during Lexical Access

Studies of context effects in speech production have shown that semantic feature overlap produces interference in naming of categorically related objects. In neuroimaging studies, this semantic interference effect is consistently associated with involvement of left superior and middle temporal gyri. However, at least part of this effect has recently been shown to be attributable to visual form similarity, as categorically related objects typically share visual features. This fMRI study examined interference produced by visual form overlap in the absence of a category relation in a picture-word interference paradigm. Both visually similar and visually dissimilar distractors led to increased BOLD responses in the left inferior frontal gyrus compared with the congruent condition. Naming pictures in context with a distractor word denoting an object visually similar in form slowed RTs compared with unrelated words and was associated with reduced activity in the left posterior middle temporal gyrus. This area is reliably observed in lexical level processing during language production tasks. No significant differential activity was observed in areas typically engaged by early perceptual or conceptual feature level processing or in areas proposed to be engaged by postlexical language processes, suggesting that visual form interference does not arise from uncertainty or confusion during perceptual or conceptual identification or after lexical processing. We conclude that visual form interference has a lexical locus, consistent with the predictions of competitive lexical selection models.

The Artery of Aphasia, A Uniquely Sensitive Posterior Temporal Middle Cerebral Artery Branch that Supplies Language Areas in the Brain: Anatomy and Report of Four Cases

BACKGROUND

Arterial disruption during brain surgery can cause devastating injuries to wide expanses of white and gray matter beyond the tumor resection cavity. Such damage may occur as a result of disrupting blood flow through en passage arteries. Identification of these arteries is critical to prevent unforeseen neurologic sequelae during brain tumor resection. In this study, we discuss one such artery, termed the artery of aphasia (AoA), which when disrupted can lead to receptive and expressive language deficits.

METHODS

We performed a retrospective review of all patients undergoing an awake craniotomy for resection of a glioma by the senior author from 2012 to 2018. Patients were included if they experienced language deficits secondary to postoperative infarction in the left posterior temporal lobe in the distribution of the AoA. The gross anatomy of the AoA was then compared with activation likelihood estimations of the auditory and semantic language networks using coordinate-based meta-analytic techniques.

RESULTS

We identified 4 patients with left-sided posterior temporal artery infarctions in the distribution of the AoA on diffusion-weighted magnetic resonance imaging. All 4 patients developed substantial expressive and receptive language deficits after surgery. Functional language improvement occurred in only 2/4 patients. Activation likelihood estimations localized parts of the auditory and semantic language networks in the distribution of the AoA.

CONCLUSIONS

The AoA is prone to blood flow disruption despite benign manipulation. Patients seem to have limited capacity for speech recovery after intraoperative ischemia in the distribution of this artery, which supplies parts of the auditory and semantic language networks.

Lexical selection with competing distractors: Evidence from left temporal lobe lesions

According to the competition account of lexical selection in word production, conceptually driven word retrieval involves the activation of a set of candidate words in left temporal cortex and competitive selection of the intended word from this set, regulated by frontal cortical mechanisms. However, the relative contribution of these brain regions to competitive lexical selection is uncertain. In the present study, five patients with left prefrontal cortex lesions (overlapping in ventral and dorsal lateral cortex), eight patients with left lateral temporal cortex lesions (overlapping in middle temporal gyrus), and 13 matched controls performed a picture-word interference task. Distractor words were semantically related or unrelated to the picture, or the name of the picture (congruent condition). Semantic interference (related vs. unrelated), tapping into competitive lexical selection, was examined. An overall semantic interference effect was observed for the control and left-temporal groups separately. The left-frontal patients did not show a reliable semantic interference effect as a group. The left-temporal patients had increased semantic interference in the error rates relative to controls. Error distribution analyses indicated that these patients had more hesitant responses for the related than for the unrelated condition. We propose that left middle temporal lesions affect the lexical activation component, making lexical selection more susceptible to errors.

Cognitive style modulates semantic interference effects: evidence from field dependency

The so-called semantic interference effect is a delay in selecting an appropriate target word in a context where semantic neighbours are strongly activated. Semantic interference effect has been described to vary from one individual to another. These differences in the susceptibility to semantic interference may be due to either differences in the ability to engage in lexical-specific selection mechanisms or to differences in the ability to engage more general, top-down inhibition mechanisms which suppress unwanted responses based on task-demands. However, semantic interference may also be modulated by an individual's disposition to separate relevant perceptual signals from noise, such as a field-independent (FI) or a field-dependent (FD) cognitive style. We investigated the relationship between semantic interference in picture naming and in an STM probe task and both the ability to inhibit responses top-down (measured through a Stroop task) and a FI/FD cognitive style measured through the embedded figures test (EFT). We found a significant relationship between semantic interference in picture naming and cognitive style-with semantic interference increasing as a function of the degree of field dependence-but no associations with the semantic probe and the Stroop task. Our results suggest that semantic interference can be modulated by cognitive style, but not by differences in the ability to engage top-down control mechanisms, at least as measured by the Stroop task.

Functional reorganization of the conceptual brain system after deafness in early childhood

The neurodevelopmental consequences of deafness on the functional neuroarchitecture of the conceptual system have not been intensively investigated so far. Using functional magnetic resonance imaging (fMRI), we therefore identified brain areas involved in conceptual processing in deaf and hearing participants. Conceptual processing was probed by a pictorial animacy decision task. Furthermore, brain areas sensitive to observing verbal signs and to observing non-verbal visual hand actions were identified in deaf participants. In hearing participants, brain areas responsive to environmental sounds and the observation of visual hand actions were determined. We found a stronger recruitment of superior and middle temporal cortex in deaf compared to hearing participants during animacy decisions. This region, which forms auditory cortex in hearing people according to the sound listening task, was also activated in deaf participants, when they observed sign language, but not when they observed non-verbal hand actions. These results indicate that conceptual processing in deaf people more strongly depends on language representations compared to hearing people. Furthermore, additionally enhanced activation in visual and motor areas of deaf versus hearing participants during animacy decisions and a more frequent report of visual and motor features in the property listing task suggest that the loss of the auditory channel is partially compensated by an increased importance of visual and motor information for constituting object knowledge. Hence, our results indicate that conceptual processing in deaf compared to hearing people is more strongly based on the language system, complemented by an enhanced contribution of the visuo-motor system.

Convergence of spoken and written language processing in the superior temporal sulcus

Spoken and written language processing streams converge in the superior temporal sulcus (STS), but the functional and anatomical nature of this convergence is not clear. We used functional MRI to quantify neural responses to spoken and written language, along with unintelligible stimuli in each modality, and employed several strategies to segregate activations on the dorsal and ventral banks of the STS. We found that intelligible and unintelligible inputs in both modalities activated the dorsal bank of the STS. The posterior dorsal bank was able to discriminate between modalities based on distributed patterns of activity, pointing to a role in encoding of phonological and orthographic word forms. The anterior dorsal bank was agnostic to input modality, suggesting that this region represents abstract lexical nodes. In the ventral bank of the STS, responses to unintelligible inputs in both modalities were attenuated, while intelligible inputs continued to drive activation, indicative of higher level semantic and syntactic processing. Our results suggest that the processing of spoken and written language converges on the posterior dorsal bank of the STS, which is the first of a heterogeneous set of language regions within the STS, with distinct functions spanning a broad range of linguistic processes.

Monitoring and Control in Language Production

Language research has provided insight into how speakers translate a thought into a sequence of sounds that ultimately becomes words, phrases, and sentences. Despite the complex stages involved in this process, relatively little is known about how we avoid and handle production and comprehension errors that would otherwise impede communication. We review current research on the mechanisms underlying monitoring and control of the language system, especially production, with particular emphasis on whether such monitoring is issued by domain-general or domain-specific procedures.

Neural evidence for phonologically based language production deficits in older adults: An fMRI investigation of age-related differences in picture-word interference

INTRODUCTION

Older adults often show declines in phonological aspects of language production, particularly for low-frequency words, but maintain strong semantic systems. However, there are different theories about the mechanism that may underlie such age-related differences in language (e.g., age-related declines in transmission of activation or inhibition).

METHODS

This study used fMRI to investigate whether age-related differences in language production are associated with transmission deficits or inhibition deficits. We used the picture-word interference paradigm to examine age-related differences in picture naming as a function of both target frequency and the relationship between the target picture and distractor word.

RESULTS

We found that the presence of a categorically related distractor led to greater semantic elaboration by older adults compared to younger adults, as evidenced by older adults' increased recruitment of regions including the left middle frontal gyrus and bilateral precuneus. When presented with a phonologically related distractor, patterns of neural activation are consistent with previously observed age deficits in phonological processing, including age-related reductions in the recruitment of regions such as the left middle temporal gyrus and right supramarginal gyrus. Lastly, older, but not younger, adults show increased brain activation of the pre- and postcentral gyri as a function of decreasing target frequency when target pictures are paired with a phonological distractor, suggesting that cuing the phonology of the target disproportionately aids production of low-frequency items.

CONCLUSIONS

Overall, this pattern of results is generally consistent with the transmission deficit hypothesis, illustrating that links within the phonological system, but not the semantic system, are weakened with age.

Feature-Specific Event-Related Potential Effects to Action- and Sound-Related Verbs during Visual Word Recognition

Grounded cognition theories suggest that conceptual representations essentially depend on modality-specific sensory and motor systems. Feature-specific brain activation across different feature types such as action or audition has been intensively investigated in nouns, while feature-specific conceptual category differences in verbs mainly focused on body part specific effects. The present work aimed at assessing whether feature-specific event-related potential (ERP) differences between action and sound concepts, as previously observed in nouns, can also be found within the word class of verbs. In Experiment 1, participants were visually presented with carefully matched sound and action verbs within a lexical decision task, which provides implicit access to word meaning and minimizes strategic access to semantic word features. Experiment 2 tested whether pre-activating the verb concept in a context phase, in which the verb is presented with a related context noun, modulates subsequent feature-specific action vs. sound verb processing within the lexical decision task. In Experiment 1, ERP analyses revealed a differential ERP polarity pattern for action and sound verbs at parietal and central electrodes similar to previous results in nouns. Pre-activation of the meaning of verbs in the preceding context phase in Experiment 2 resulted in a polarity-reversal of feature-specific ERP effects in the lexical decision task compared with Experiment 1. This parallels analogous earlier findings for primed action and sound related nouns. In line with grounded cognitions theories, our ERP study provides evidence for a differential processing of action and sound verbs similar to earlier observation for concrete nouns. Although the localizational value of ERPs must be viewed with caution, our results indicate that the meaning of verbs is linked to different neural circuits depending on conceptual feature relevance.

The Brain Effective Connectivity of Chinese during Rhyming Task

With regard to brain language processing, the activation patterns have been well studied, and recently there are great interest in the connectivity models. The crucial brain areas for phonological processing involves left inferior frontal gyrus (LIFG), left inferior parietal lobule (LIPL) and left posterior middle temporal gyrus (LpMTG). Specially in Chinese processing, the left middle frontal gyrus (LMFG) is considered as an essential region. However, the connectivity pattern among these brain areas is not well understood. In this study, a rhyming experiment of Chinese was conducted, and the Dynamic causal modeling (DCM) and the Bayesian model selection (BMS) were used to examine the interaction between brain regions and choose the best model for rhyming task of Chinese. By examining the interactions, it was found that LMFG exerted inhibitory modulation on LIPL and LIFG; the phonological processing enhanced the connection from LIPL to LIFG and LMFG, which suggested the important roles of these connections for the increased phonological load; And LpMTG modulated LIFG and LMFG negatively, and LIPL positively under rhyming judgment task.