Search

Published: 01 February 2023 The intention to name an object modulates neural responses during object recognition tasks. However, the nature of this modulation is still unclear. We established whether a core operation in language, i.e. lexical access, can be observed even when the task does not require language (size-judgment task), and whether response selection in verbal versus non-verbal semantic tasks relies on similar neuronal processes. We measured and compared neuronal oscillatory activities and behavioral responses to the same set of pictures of meaningful objects, while the type of task participants had to perform (picture-naming versus size-judgment) and the type of stimuli to measure lexical access (cognate versus non-cognate) were manipulated. Despite activation of words was facilitated when the task required explicit word-retrieval (picture-naming task), lexical access occurred even without the intention to name the object (non-verbal size-judgment task). Activation of words and response selection were accompanied by beta (25–35 Hz) desynchronization and theta (3–7 Hz) synchronization, respectively. These effects were observed in both picture-naming and size-judgment tasks, suggesting that words became activated via similar mechanisms, irrespective of whether the task involves language explicitly. This finding has important implications to understand the link between core linguistic operations and performance in verbal and non-verbal semantic tasks. This work was supported by a Sir Henry Wellcome Postdoctoral Fellowship awarded to E.B. (Grant reference number: 210924/Z/18/Z). C.D.M received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant Agreement No: 819093) and the Spanish Ministry of Economy and Competitiveness (PID2020-113926GB-I00). The authors acknowledge the Basque Government through the BERC 2022-2025 program and the Spanish State Research Agency through BCBL Severo Ochoa excellence accreditation CEX2020-001010-S.

Recent research has highlighted the importance of domain-general processes and brain regions for language and semantic cognition. Yet, this has been mainly observed in executively demanding tasks, leaving open the question of the contribution of domain-general processes to natural language and semantic cognition. Using fMRI, we investigated whether neural processes reflecting context integration and context update – two key aspects of naturalistic language and semantic processing – are domain-specific versus domain-general. Thus, we compared neural responses during integration of contextual information across semantic and non-semantic tasks. Whole-brain results revealed both shared (left posterior-dorsal inferior frontal gyrus, left posterior inferior temporal gyrus, and left dorsal angular gyrus/intraparietal sulcus) and distinct (left anterior-ventral inferior frontal gyrus, left anterior ventral angular gyrus, left posterior middle temporal gyrus for semantic control only) regions involved in context integration and update. Furthermore, data-driven functional connectivity analysis clustered domain-specific versus domain-general brain regions into distinct but interacting functional neural networks. These results provide a first characterization of the neural processes required for context-dependent integration during language processing along the domain-specificity dimension, and at the same time, they bring new insights on the role of left posterior lateral temporal cortex and left angular gyrus for semantic cognition.

A long history of neuropsychology and neuroimaging has implicated the angular gyrus (AG) with a myriad of cognitive functions. We investigated the functional engagement of AG by three forms of memory: 1) episodic/autobiographical memory 2) object semantic-memory, and 3) event-semantic processing using the previously under-examined naturalistic task of propositional speech production. We conducted an ALE meta-analysis of imaging studies of propositional speech, followed by an fMRI study in which we conducted direct cross-domain comparisons. The results from the meta-analysis suggest that the AG is only engaged as part of the propositional speech network when the task carries an autobiographical component. This conclusion was strongly supported by the results from the fMRI study. The key fMRI findings were: 1) AG was positively engaged during autobiographical memory retrieval. 2) The AG was strongly deactivated for definitions of object semantics and non-propositional speech. 3) The level of AG activation increased with the degree to which the event descriptions relied on input from the episodic memory system. 4) Critically, the AG showed a very different pattern to that of known semantic representation regions (the anterior temporal lobe; ATL) - whilst AG activation increased with the autobiographical nature of the task, the ATL was equally responsive to all conditions. These results provide clear evidence that the AG is not acting as a semantic hub. In contrast, the AG activation profile directly mirrored that found in the wider autobiographical retrieval network. We propose that information stored elsewhere in the episodic system is temporally buffered online in the AG during autobiographical retrieval/memory construction.

Published:17 December 2021 The left ventral occipito-temporal cortex (vOTC) supports extraction and processing of visual features. However, it has remained unclear whether left vOTC-based functional connectivity (FC) differs according to task-relevant representations (e.g., lexical, visual) and control demands imposed by the task, even when similar visual-semantic processing is required for object identification. Here, neural responses to the same set of pictures of meaningful objects were measured, while the type of task that participants had to perform (picture naming versus size-judgment task), and the level of cognitive control required by the picture naming task (high versus low interference contexts) were manipulated. Explicit retrieval of lexical representations in the picture naming task facilitated activation of lexical/phonological representations, modulating FC between left vOTC and dorsal anterior-cingulate-cortex/pre-supplementary-motor-area. This effect was not observed in the size-judgment task, which did not require explicit word-retrieval of object names. Furthermore, retrieving the very same lexical/phonological representation in the high versus low interference contexts during picture naming increased FC between left vOTC and left caudate. These findings support the proposal that vOTC functional specialization emerges from interactions with task-relevant brain regions. Francesca M. Branzi was supported by a H2020 European Research Council grant (GAP: 670428-BRAIN2 MIND_NEUROCOMP). Clara D. Martin was supported by grants from the H2020 European Research Council [ERC Consolidator Grant ERC-2018-COG-819093], the Spanish Ministry of Economy and Competitiveness [PID2020-113926GB-I00], the Basque Government [PIBA18-29]. Pedro M. Paz-Alonso was supported by grants from the Spanish Ministry of Science and Innovation [RYC-2014-15440; PGC2018-093408-B-I00], Neuroscience projects from the Fundación Tatiana Pérez de Guzmán el Bueno, and the Basque Government [PIBA-2021-1-0003]. BCBL acknowledges support by the Basque Government through the BERC 2018-2021 program and by the Spanish State Research Agency through BCBL Severo Ochoa excellence accreditation SEV-2015-0490. The authors also acknowledge the Medical Research intramural funding (MC_UU_00005/18).

The role of the left angular gyrus (AG) in language processing remains unclear. In this study, we used TMS to test the hypothesis that the left AG causally supports the processes necessary for context-dependent integration and encoding of information during language processing. We applied on-line TMS over the left AG to disrupt the on-line context-dependent integration during a language reading task, specifically while human participants integrated information between two sequentially presented paragraphs of text (“context” and “target” paragraphs). We assessed the effect of TMS on the left AG by asking participants to retrieve integrated contextual information when given the target condition as cue in a successive memory task. Results from the memory task showed that TMS applied over the left AG during reading impaired the formation of integrated context-target representation. These results provide the first evidence of a causal link between the left AG function, on-line information integration, and associative encoding during language processing.

During picture naming, the ease with which humans generate words is dependent upon the context in which they are named. For instances, naming previously presented items results in facilitation. Instead, naming a picture semantically related to previous items displays persistent interference effects (i.e., cumulative semantic interference, CSI). The neural correlates of CSI are still unclear and it is a matter of debate whether semantic control, or cognitive control more in general, is necessary for the resolution of CSI. We carried out an event-related fMRI experiment to assess the neural underpinnings of the CSI effect and the involvement and nature of semantic control. Both left inferior frontal gyrus (LIFG) and the left caudate nucleus (LCN) showed a linear increase of BOLD response positively associated with the consecutive number of presentations of semantically related pictures independently of task-load. The generalized psychophysiological interaction analysis showed that LIFG demonstrated a quantitative neural connectivity difference with the left supramarginal and angular gyri for increases of task-load and with the fusiform gyri for linear CSI increases. Furthermore, seed-to-voxel functional connectivity showed that LIFG activity coupled with different regions involved in cognitive control and lexicosemantic processing when semantic interference was elicited to a minimum or maximum degree. Our results are consistent with the lexical-competitive nature of the CSI effect, and we provide novel evidence that semantic control lies upon a more general cognitive control network (i.e., LIFG and LCN) responsible for resolving interference between competing semantically related items through connectivity with different brain areas in order to guarantee the correct response.

The bilingual population nowadays represents a global majority. Hence, the need of elaborating comprehensive theories of lexical access reflecting this reality is becoming increasingly relevant. This chapter presents a critical overview of the most prominent psycholinguistic models of bilingual language production and it tackles different theoretical issues that are currently controversial in the field. The first one concerns whether bilingual lexical access is competitive. Does competition occur between nodes in all of a speaker’s languages, or only between nodes in the target language? A second issue concerns the nature of the mechanisms applied during lexical access (i.e. is language selection resolved through domain-general or language-specific mechanisms?). If bilingual lexical access is competitive and language-non-specific, do the current theories account for the data or do we need to update them? This chapter tries to answer these questions by providing the most recent evidence on mechanisms of bilingual language production.

In one task-switching experiment, we compared bilinguals and monolinguals to explore the reliability of the bilingualism effect on the n-2 repetition cost. In a second taskswitching experiment, we tested another group of bilinguals and monolinguals and measured both the n-1 shift cost and the n-2 repetition cost to test the hypothesis that bilingualism should confer a general greater efficiency of the executive control functioning. According to this hypothesis, we expected a reduced n-1 shift cost and an enhanced n-2 repetition cost for bilinguals compared to monolinguals. However, we did not observe such results. Our findings suggest that previous results cannot be replicated and that the n-2 repetition cost is another index that shows no reliable bilingualism effect. Finally, we observed a negative correlation between the two switch costs among bilinguals only. This finding may suggest that the two groups employ different strategies to cope with interference in task-switching paradigms. We are grateful to Dr. Kenneth Paap and Dr. Mireia Hernández for their useful comments on the previous versions of this manuscript. This work was supported by grants from the Spanish Government (PSI2014-54500, PSI2008-01191, PSI2011-23033, PSI2014-53427-P, Consolider Ingenio 2010 CSD2007-00012), the Catalan Government (Consolidat SGR 2009-1521 and SGR 2014-1210), by one grant from the European Research Council under the European Community’s Seventh Framework (FP7/2007-2013 Cooperation grant agreement 613465-AThEME), by one grant from Fundación Séneca (19267/PI/14) and by the Severo Ochoa program grant SEV-2015-049. Francesca M. Branzi was supported by a predoctoral fellowship from the Spanish Government (FPU-2009-2013) and by a postdoctoral fellowship from the European Union’s Horizon 2020 research and innovation programme, under the Marie Sklodowska-Curie grant agreement No 658341. Marco Calabria was supported by a postdoctoral fellowship from the Spanish Government (Ramón y Cajal Fellowship).

The aim of the present study is two-fold. First, we investigate age-related changes to bilingual language control (bLC) mechanisms across lifespan. Second, we explore the relation between bLC mechanisms and those of the domain-general executive (EC) system by looking at age effects on these two systems. To do so, we compare the performances of the three age groups of bilinguals (young, middle-aged and elderly) in a language switching task to those of non-linguistic switching task. We found an age-related change in the non-linguistic switch cost but not in the language switch cost. Moreover, we did not find any correlation between the magnitudes of the switch costs. Taken together these results indicate that bLC is not affected by age as the EC system is, and interestingly, we add new evidence that the bLC mechanisms are not fully subsidiary to those of the domain-general EC system.

How does the bilingual brain distinguish and control which language to use? A large body of research has been dedicated to answering this question by mainly using the language switching paradigm that taps into different language control mechanisms. This research has been fruitful in revealing both the time course and the brain areas involved in bilingual language control. In this chapter, we review this research and derive two main conclusions. First, the cognitive and neural mechanisms involved in bilingual language control seem to be influenced by various sociolinguistic factors, including language proficiency. Second, “sustained” and “transient” components of control are differently involved in the control of the two languages because they recruit different brain networks. This observation may suggest that different qualitative processes are applied to dominant and nondominant languages to ensure successful speech production in bilinguals.

Available online 1 April 2016 We explored the overlap between bilingual language control (bLC) and domain-general executive control (EC) by focusing on inhibitory control processes. We tested 62 bilinguals in linguistic and non-linguistic switching tasks for two types of costs, such as the n−1 shift cost and the n−2 repetition cost. In order to explore the involvement of inhibitory control in bLC and EC, we assessed the pattern of switch costs in the two tasks and then we correlated them between tasks. Results showed reduced n − 2 repetition costs as compared to n − 1 shift costs in the linguistic task only, suggesting that small amount of inhibition were deployed when switching between languages. Importantly, neither the n − 1 shift costs nor the n − 2 repetition costs were correlated between tasks. These results, supported by additional evidence fromthe ex-Gaussian analysis, suggest that inhibitory control is differently involved in bLC and in EC. This work was supported by grants from the Spanish Government (PSI2014-54500, PSI2008-01191, PSI2011-23033, PSI2011-23340, Consolider Ingenio 2010 CSD2007-00012), the Catalan Government (Consolidat SGR 2009-1521and SGR 2014-1210) and by one grant from the European Research Council under the European Community’s Seventh Framework (FP7/2007-2013 Cooperation grant agreement 613465-AThEME). This research received partial financial assistance as a Severo Ochoa Center of Excellence SEV-2015-0490. FrancescaM. Branziwas supported by a predoctoral fellowship from the Spanish Government (FPU-2009-2013) and by a postdoctoral fellowship fromthe European Union’s Horizon 2020 research and innovation programme, under the Marie Sklodowska-Curie grant agreement No 658341. Marco Calabria was supported by a postdoctoral fellowship from the Spanish Government (Ramón y Cajal Fellowship).

We explored the temporal course of bilingual language control after-effects to shed light on the scope of language control (local vs. global) and on the way in which language control is implemented (L1 inhibition or L2 over-activation). High-proficient bilinguals named objects across three blocks, first in their L1, then in their L2, and then again in their L1 (and conversely) while event-related brain potentials (ERPs) were recorded. Behaviorally we found only the L1 as being hindered by previous naming in the L2. In the ERPs we did not observe inhibitory effects in the N2 component time-window. However, the P2 component showed more positive-going deflections when the previous language slowed down naming latencies of the successive language. The P2 mean amplitude predicted naming latencies whereas the N2 did not. We conclude that in high-proficient bilinguals the P2 component is the marker of language control mechanisms other than inhibition, which are applied globally.