Relational vs. attributive interpretation of nominal compounds differentially engages angular gyrus and anterior temporal lobe

Disruption of Anterior Temporal Lobe Reduces Distortions in Memory From Category Knowledge

Memory retrieval does not provide a perfect recapitulation of past events, but instead an imperfect reconstruction of event-specific details and general knowledge. However, it remains unclear whether this reconstruction relies on mixtures of signals from different memory systems, including one supporting general knowledge. Here, we investigate whether the anterior temporal lobe (ATL) distorts new memories because of prior category knowledge. In this preregistered experiment (n = 36), participants encoded and retrieved image-location associations. Most images' locations were clustered according to their category, but some were in random locations. With this protocol, we previously demonstrated that randomly located images were retrieved closer to their category cluster relative to their encoded locations, suggesting an influence of category knowledge. We combined this procedure with TMS delivered to the left ATL before retrieval. We separately examined event-specific details (error) and category knowledge (bias) to identify distinct signals attributable to different memory systems. We found that TMS to ATL attenuated bias in location memory, but this effect was limited to exploratory analyses of atypical category members of animal categories. The magnitude of error was not impacted, suggesting that a memory's fidelity can be decoupled from its distortion by category knowledge. This raises the intriguing possibility that retrieval is jointly supported by separable memory systems.

Constructing complex social categories under uncertainty

Conceptual combination is the act of building complex concepts from simpler ones. Although research has examined how inferences about compound objects (e.g., fuzzy chair) are produced from their constituent concepts, little is known about the combinatorial processes that produce inferences about compound social categories (e.g., Irish musician). Using a computational approach, we investigated the relationship between ratings of 25 nationality-occupation combinations and ratings of their constituent concepts along the attribute dimensions of warmth and competence. We found that people incorporate uncertainty into their perceptions of compound social categories. Further, people are more likely to use a linear combination strategy when they are more certain about the attributes of the constituents and less familiar with the combination. Conversely, when social combinations are more familiar, their judged attributes deviate further from the predictions of a combinatorial model and are shared across participants, suggesting that stereotype-based knowledge plays a central role in the representation of complex social groups. Twenty-five non-human animal combinations (e.g., circus snake) serve as a comparison and were rated on size and ferocity. We found evidence that familiarity has different effects on the strategies used to combine person concepts and animal concepts, pointing to the possible existence of both common and distinct mechanisms for constructing social and non-social categories.

Conceptual Combination in the LATL With and Without Syntactic Composition

The relationship among syntactic, semantic, and conceptual processes in language comprehension is a central question to the neurobiology of language. Several studies have suggested that conceptual combination in particular can be localized to the left anterior temporal lobe (LATL), while syntactic processes are more often associated with the posterior temporal lobe or inferior frontal gyrus. However, LATL activity can also correlate with syntactic computations, particularly in narrative comprehension. Here we investigated the degree to which LATL conceptual combination is dependent on syntax, specifically asking whether rapid (∼200 ms) magnetoencephalography effects of conceptual combination in the LATL can occur in the absence of licit syntactic phrase closure and in the absence of a semantically plausible output for the composition. We find that such effects do occur: LATL effects of conceptual combination were observed even when there was no syntactic phrase closure or plausible meaning. But syntactic closure did have an additive effect such that LATL signals were the highest for expressions that composed both conceptually and syntactically. Our findings conform to an account in which LATL conceptual composition is influenced by local syntactic composition but is also able to operate without it.

Composition within and between Languages in the Bilingual Mind: MEG Evidence from Korean/English Bilinguals

The ability of the human brain to build complex expressions from simpler parts is fascinating, but the ability of the bilingual brain to do so is perhaps even more remarkable. When highly proficient bilinguals converse, they can fluidly switch from one language to another even inside sentences. Thus, they build expressions using words from more than one language. How are bilinguals able to compose words across different languages in real time? While robust evidence has implicated the left anterior temporal lobe (LATL) for the composition of words within one language, we do not know how the LATL, or other regions implicated for composition, operates when the language switches. We also do not know whether prefrontal regions associated with language control are recruited for language switching during composition. We addressed these questions with magnetoencephalography measurements in bilinguals who are fluent in two typologically distant languages, English and Korean. We observed early composition effects in the LATL at ∼200 ms that were unaffected by either language or orthography switching, which was also varied (Hangul vs Roman alphabet). Thus, the combinatory mechanism at 200 ms housed in the anterior temporal cortex appears blind to the language in which its input concepts are expressed. However, in later time windows, language and orthography switching interacted both in regions implicated for composition [LATL, ventromedial prefrontal cortex, left inferior frontal gyrus (LIFG)] as well as in regions associated with language control (ACC, LIFG). This establishes a starting point for understanding how bilingual brains code switch: words are initially combined without consideration of which language they come from, but language switching affects later processing.

Commonalities and Asymmetries in the Neurobiological Infrastructure for Language Production and Comprehension

The neurobiology of sentence production has been largely understudied compared to the neurobiology of sentence comprehension, due to difficulties with experimental control and motion-related artifacts in neuroimaging. We studied the neural response to constituents of increasing size and specifically focused on the similarities and differences in the production and comprehension of the same stimuli. Participants had to either produce or listen to stimuli in a gradient of constituent size based on a visual prompt. Larger constituent sizes engaged the left inferior frontal gyrus (LIFG) and middle temporal gyrus (LMTG) extending to inferior parietal areas in both production and comprehension, confirming that the neural resources for syntactic encoding and decoding are largely overlapping. An ROI analysis in LIFG and LMTG also showed that production elicited larger responses to constituent size than comprehension and that the LMTG was more engaged in comprehension than production, while the LIFG was more engaged in production than comprehension. Finally, increasing constituent size was characterized by later BOLD peaks in comprehension but earlier peaks in production. These results show that syntactic encoding and parsing engage overlapping areas, but there are asymmetries in the engagement of the language network due to the specific requirements of production and comprehension.

Dissociating nouns and verbs in temporal and perisylvian networks: Evidence from neurodegenerative diseases

Naming of nouns and verbs can be selectively impaired in neurological disorders, but the specificity of the neural and cognitive correlates of such dissociation remains unclear. Functional imaging and stroke research sought to identify cortical regions selectively recruited for nouns versus verbs, yet findings are inconsistent. The present study investigated this issue in neurodegenerative diseases known to selectively affect different brain networks, thus providing new critical evidence of network specificity. We examined naming performances on nouns and verbs in 146 patients with different neurodegenerative syndromes (Primary Progressive Aphasia - PPA, Alzheimer's disease - AD, and behavioral variant Frontotemporal Dementia - FTD) and 30 healthy adults. We then correlated naming scores with MRI-derived cortical thickness values as well as with performances in semantic and syntactic tasks, across all subjects. Results indicated that patients with the semantic variant PPA named significantly fewer nouns than verbs. Instead, nonfluent/agrammatic PPA patients named fewer verbs than nouns. Across all subjects, performance on nouns (adjusted for verbs) specifically correlated with cortical atrophy in left anterior temporal regions, and performance on verbs (adjusted for nouns) with atrophy in left inferior and middle frontal, inferior parietal and posterior temporal regions. Furthermore, lower lexical-semantic abilities correlated with deficits in naming both nouns and verbs, while lower syntactic abilities only correlated with naming verbs. Our results show that different neural and cognitive mechanisms underlie naming of specific grammatical categories in neurodegenerative diseases. Importantly, our findings showed that verb processing depends on a widespread perisylvian networks, suggesting that some regions might be involved in processing different types of action knowledge. These findings have important implications for early differential diagnosis of neurodegenerative disorders.

From letters to composed concepts: A magnetoencephalography study of reading

Language comprehension requires the recognition of individual words and the combination of their meanings to yield complex concepts or interpretations. This combinatory process often requires the insertion of unstated semantic material between words, based on thematic or feature knowledge. For example, the phrase horse barn is not interpreted as a blend of a horse and a barn, but specifically a barn where horses are kept. Previous neuroscientific evidence suggests that left posterior and anterior temporal cortex underpin thematic and feature‐based concept knowledge, respectively, but much remains unclear about how these areas contribute to combinatory language processing. Using magnetoencephalography, we contrasted source‐localized responses to modifier‐noun phrases involving thematic relations versus feature modifications, while also examining how lower‐level orthographic processing fed composition. Participants completed three procedures examining responses to letter‐strings, adjective‐noun phrases, and noun–noun combinations that varied the semantic relations between words. We found that sections of the left anterior temporal lobe, posterior temporal lobe, and cortex surrounding the angular gyrus were all engaged in the minimal composition of adjective‐noun phrases, a more distributed network than in most prior studies of minimal composition. Of these regions, only the left posterior temporal lobe was additionally sensitive to implicit thematic relations between composing words, suggesting that it houses a specialized relational processing component in a wider composition network. We additionally identified a left occipitotemporal progression from orthographic to lexical processing, feeding ventral anterior areas engaged in the combination of word meanings. Finally, by examining source signal leakage, we characterized the degree to which these responses could be distinguished from one another using source estimation.

Asymmetric Underlying Mechanisms of Relation-Based and Property-Based Noun-Noun Conceptual Combination

Conceptual combination is a fundamental human cognitive ability by which people can experience infinite thinking by artfully combining finite knowledge. For example, one can instantly combine “cactus” and “fish” together as “prickly fish” even if one has never previously heard of a “cactus fish.” Although two major combinatorial types—property and relational combinations—have been identified, the underlying processes of each remain elusive. This study investigates the asymmetric processing mechanisms underlying property and relational combinations by examining differential semantic activation during noun–noun conceptual combination. Across two experiments utilizing each combinatorial process as semantic priming and implementing a lexical decision task immediately after combination, we measure and compare the semantic activation patterns of intrinsic and extrinsic semantic features in these two combinatorial types. We found converging evidence that property and relational combinations involve asymmetric semantic information and entail distinct processing mechanisms. In property combination, the intrinsic feature in the modifier concept showed greater activation than the semantic feature of the same dimension in the head concept. In contrast, in relational combination, the extrinsic semantic feature in the head concept and the whole modifier concept showed similar levels of activation. Moreover, our findings also showed that these patterns of semantic activation occurred only when the combinatorial process was complete, indicating that accessing the same lexical-semantic information is not sufficient to observe asymmetric patterns. These findings demonstrate that property combination involves replacing a specific semantic feature of the head noun with that of the modifier noun, whereas relational combination involves completing the semantic feature of the head noun with the whole modifier concept. We discuss the implications of these findings, research limitations, and future research directions.

Differential contributions of left-hemispheric language regions to basic semantic composition

Semantic composition, the ability to combine single words to form complex meanings, is a core feature of human language. Despite growing interest in the basis of semantic composition, the neural correlates and the interaction of regions within this network remain a matter of debate. We designed a well-controlled two-word fMRI paradigm in which phrases only differed along the semantic dimension while keeping syntactic information alike. Healthy participants listened to meaningful ("fresh apple"), anomalous ("awake apple") and pseudoword phrases ("awake gufel") while performing an implicit and an explicit semantic task. We identified neural signatures for distinct processes during basic semantic composition. When lexical information is kept constant across conditions and the evaluation of phrasal plausibility is examined (meaningful vs. anomalous phrases), a small set of mostly left-hemispheric semantic regions, including the anterior part of the left angular gyrus, is found active. Conversely, when the load of lexical information-independently of phrasal plausibility-is varied (meaningful or anomalous vs. pseudoword phrases), conceptual combination involves a wide-spread left-hemispheric network comprising executive semantic control regions and general conceptual representation regions. Within this network, the functional coupling between the left anterior inferior frontal gyrus, the bilateral pre-supplementary motor area and the posterior angular gyrus specifically increases for meaningful phrases relative to pseudoword phrases. Stronger effects in the explicit task further suggest task-dependent neural recruitment. Overall, we provide a separation between distinct nodes of the semantic network, whose functional contributions depend on the type of compositional process under analysis.

Common and distinct neural substrates of sentence production and comprehension

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

Feature Uncertainty Predicts Behavioral and Neural Responses to Combined Concepts

The cognitive and neural structure of conceptual knowledge affects how concepts combine in language and thought. Examining the principles by which individual concepts (e.g., diamond, baseball) combine into more complex phrases (e.g., "baseball diamond") can illuminate not only how the brain combines concepts but also the key ingredients of conceptual structure. Here we specifically tested the role of feature uncertainty in the modulation of conceptual brightness evoked by adjective-noun combinations (e.g., "dark diamond") in male and female human subjects. We collected explicit ratings of conceptual brightness for 45 noun concepts and their "dark" and "light" combinations, resulting in a measure reflecting the degree of conceptual brightness modulation in each noun concept. Feature uncertainty was captured in an entropy measure, as well as in a predictive Bayesian model of feature modulation. We found that feature uncertainty (i.e., entropy) and the Bayesian model were both strong predictors of these behavioral effects. Using fMRI, we observed the neural responses evoked by the concepts and combinations in a priori ROIs. Feature uncertainty predicted univariate responses in left inferior frontal gyrus, and multivariate responses in left anterior temporal lobe were predicted by degree of conceptual brightness modulation. These findings suggest that feature uncertainty is a key ingredient of conceptual structure, and inform cognitive neuroscience theories of conceptual combination by highlighting the role of left inferior frontal gyrus and left anterior temporal lobe in the process of flexible feature modulation during comprehension of complex language.SIGNIFICANCE STATEMENT The meaning of a word depends on the words surrounding it. The challenge of understanding how flexible meaning emerges in language can be simplified by studying adjective-noun phrases. We tested whether the uncertainty of a feature (i.e., brightness) in a given noun concept (e.g., diamond) influences how the adjective and noun concepts combine. We analyzed feature uncertainty using two probabilistic measures, and found that feature uncertainty predicted people's explicit interpretations of adjective-noun phrases (e.g., "dark diamond"). Using fMRI, we found that combined concepts evoked responses in left inferior frontal gyrus and left anterior temporal lobe that related to our measures of feature modulation and uncertainty. These findings reveal the cognitive and neural processes supporting conceptual combination and complex language use.

The Cortical Organization of Syntax

Syntax, the structure of sentences, enables humans to express an infinite range of meanings through finite means. The neurobiology of syntax has been intensely studied but with little consensus. Two main candidate regions have been identified: the posterior inferior frontal gyrus (pIFG) and the posterior middle temporal gyrus (pMTG). Integrating research in linguistics, psycholinguistics, and neuroscience, we propose a neuroanatomical framework for syntax that attributes distinct syntactic computations to these regions in a unified model. The key theoretical advances are adopting a modern lexicalized view of syntax in which the lexicon and syntactic rules are intertwined, and recognizing a computational asymmetry in the role of syntax during comprehension and production. Our model postulates a hierarchical lexical-syntactic function to the pMTG, which interconnects previously identified speech perception and conceptual-semantic systems in the temporal and inferior parietal lobes, crucial for both sentence production and comprehension. These relational hierarchies are transformed via the pIFG into morpho-syntactic sequences, primarily tied to production. We show how this architecture provides a better account of the full range of data and is consistent with recent proposals regarding the organization of phonological processes in the brain.

Dissociating the neural correlates of the sociality and plausibility effects in simple conceptual combination

Neuroimaging studies have indicated that a brain network distributed in the supramodal cortical regions of the frontal, temporal, and parietal lobes plays a central role in conceptual processing. The activation of this network is modulated by two orthogonal dimensions in conceptual processing-the semantic features of individual concepts and the meaningfulness of conceptual combinations-but it remains unclear how the network is functionally organized along these two dimensions. In this fMRI study, we focused on two specific factors, i.e. the social semantic richness of words and the semantic plausibility of word combinations, along the two dimensions. In literature, the distributions of the effects of the two factors are very similar, but have not been rigorously compared in one study. We orthogonally manipulated the two factors in a phrase comprehension task and found a clear dissociation between their effects. The combination of these results with our previous findings reveals three adjacently distributed subnetworks of the supramodal semantic network, associated with the sociality effect, imageability effect, and semantic plausibility effect, respectively. Further analysis of the resting-state functional connectivity data indicated that the functional dissociation among the three subnetworks is associated with their underlying intrinsic connectivity structures.

Relational processing in the semantic domain is impaired in medial temporal lobe amnesia

It has been argued that the hippocampus supports cognition by virtue of its role in flexibly binding together distinct elements of experience. Such 'relational processing' enables us to (re)construct episodic representations of real or imagined events. The present study examined whether hippocampally mediated relational processing also contributes to the construction of semantic representations. To do so, we asked amnesic individuals with medial temporal lobe (MTL) lesions including the hippocampus to generate hypothetical meanings for novel word compounds (e.g., cactus carpet), a task that requires existing concepts to be flexibly linked. The quality of definitions and number of features generated for the novel compounds were lower in patients with MTL lesions than in control participants. Whereas the subset of patients with lesions extending into lateral temporal cortex had additional difficulty generating meanings for pre-existing compounds (e.g., bus station), patients with lesions limited to the MTL showed no such deficit, indicating that their impairment in the novel compound condition was not due to reduced access to semantic information. These findings suggest that the role of hippocampally mediated relational processing extends beyond the episodic domain to include the generation of novel semantic representations.

Adult Age Differences in the Use of Conceptual Combination as an Associative Encoding Strategy

It is well-established that aging impairs memory for associations more than it does memory for single items. Aging also impacts processes involved in online language comprehension, including the ability to form integrated, message-level representations. These changes in comprehension processes could impact older adults’ associative memory performance, perhaps by reducing or altering the effectiveness of encoding strategies that encourage semantic integration. The present study examined age differences in the use of a strategy termed conceptual combination, which involves integrating two words (e.g., “winter” and “salad”) into a single concept (“a salad for winter”). We recorded ERPs while participants studied unrelated noun pairs using a strategy that either did or did not encourage conceptual combination. We also varied the concreteness of the first noun in each pair in order to measure compositional concreteness effects, or ERP differences at the second noun due to the concreteness of the first noun. At the first nouns, older adults showed word-level concreteness effects that were similar to those of younger adults. However, compositional concreteness effects were diminished in older adults, consistent with reduced semantic integration. Older adults’ associative memory performance was better for word pairs studied during the conceptual combination task versus the non-combinatory encoding task; however, the magnitude of the age-related associative memory deficit did not differ between tasks. Finally, analyses of both memory accuracy and trial-by-trial ratings of perceived combination success suggested that older adults had disproportionate difficulty applying the conceptual combination strategy to word pairs that began with abstract nouns. Overall, these results indicate that changes to integrative language processing that occur with age are not independent of – and may sometimes exacerbate – age-related memory decline.

Neural Connectivity in Syntactic Movement Processing

Linguistic theory suggests non-canonical sentences subvert the dominant agent-verb-theme order in English via displacement of sentence constituents to argument (NP-movement) or non-argument positions (wh-movement). Both processes have been associated with the left inferior frontal gyrus and posterior superior temporal gyrus, but differences in neural activity and connectivity between movement types have not been investigated. In the current study, functional magnetic resonance imaging data were acquired from 21 adult participants during an auditory sentence-picture verification task using passive and active sentences contrasted to isolate NP-movement, and object- and subject-cleft sentences contrasted to isolate wh-movement. Then, functional magnetic resonance imaging data from regions common to both movement types were entered into a dynamic causal modeling analysis to examine effective connectivity for wh-movement and NP-movement. Results showed greater left inferior frontal gyrus activation for Wh > NP-movement, but no activation for NP > Wh-movement. Both types of movement elicited activity in the opercular part of the left inferior frontal gyrus, left posterior superior temporal gyrus, and left medial superior frontal gyrus. The dynamic causal modeling analyses indicated that neither movement type significantly modulated the connection from the left inferior frontal gyrus to the left posterior superior temporal gyrus, nor vice-versa, suggesting no connectivity differences between wh- and NP-movement. These findings support the idea that increased complexity of wh-structures, compared to sentences with NP-movement, requires greater engagement of cognitive resources via increased neural activity in the left inferior frontal gyrus, but both movement types engage similar neural networks.

The temporal dynamics of structure and content in sentence comprehension: Evidence from fMRI-constrained MEG

Humans have a striking capacity to combine words into sentences that express new meanings. Previous research has identified key brain regions involved in this capacity, but little is known about the time course of activity in these regions, as hemodynamic methods such as fMRI provide little insight into temporal dynamics of neural activation. We performed an MEG experiment to elucidate the temporal dynamics of structure and content processing within four brain regions implicated by fMRI data from the same experiment: the temporo-parietal junction (TPJ), the posterior temporal lobe (PTL), the anterior temporal lobe (ATL), and the anterior inferior frontal gyrus (IFG). The TPJ showed increased activity for both structure and content near the end of the sentence, consistent with a role in incremental interpretation of event semantics. The PTL, a region not often associated with core aspects of syntax, showed a strong early effect of structure, consistent with predictive parsing models, and both structural and semantic context effects on function words. These results provide converging evidence that the PTL plays an important role in lexicalized syntactic processing. The ATL and IFG, regions traditionally associated with syntax, showed minimal effects of sentence structure. The ATL, PTL and IFG all showed effects of semantic content: increased activation for real words relative to nonwords. Our fMRI-guided MEG investigation therefore helps identify syntactic and semantic aspects of sentence comprehension in the brain in both spatial and temporal dimensions.

Neural networks for sentence comprehension and production: An ALE-based meta-analysis of neuroimaging studies

Comprehending and producing sentences is a complex endeavor requiring the coordinated activity of multiple brain regions. We examined three issues related to the brain networks underlying sentence comprehension and production in healthy individuals: First, which regions are recruited for sentence comprehension and sentence production? Second, are there differences for auditory sentence comprehension vs. visual sentence comprehension? Third, which regions are specifically recruited for the comprehension of syntactically complex sentences? Results from activation likelihood estimation (ALE) analyses (from 45 studies) implicated a sentence comprehension network occupying bilateral frontal and temporal lobe regions. Regions implicated in production (from 15 studies) overlapped with the set of regions associated with sentence comprehension in the left hemisphere, but did not include inferior frontal cortex, and did not extend to the right hemisphere. Modality differences between auditory and visual sentence comprehension were found principally in the temporal lobes. Results from the analysis of complex syntax (from 37 studies) showed engagement of left inferior frontal and posterior temporal regions, as well as the right insula. The involvement of the right hemisphere in the comprehension of these structures has potentially important implications for language treatment and recovery in individuals with agrammatic aphasia following left hemisphere brain damage.

What does the functional organization of cortico-hippocampal networks tell us about the functional organization of memory?

Historically, research on the cognitive processes that support human memory proceeded, to a large extent, independently of research on the neural basis of memory. Accumulating evidence from neuroimaging, however, has enabled the field to develop a broader and more integrative perspective. Here, we briefly outline how advances in cognitive neuroscience can potentially shed light on concepts and controversies in human memory research. We argue that research on the functional properties of cortico-hippocampal networks informs us about how memories might be organized in the brain, which, in turn, helps to reconcile seemingly disparate perspectives in cognitive psychology. Finally, we discuss several open questions and directions for future research.

Implication of N400 and P600 waves in the Linguistic Code Change in Monolinguals and Bilinguals

There is evidence of the importance of N400 and P600 waves in linguistic processes, theses brain waves are related to syntax. This work proposes to evaluate learning process through the analysis of responses generated when formulation of word is requested, an artificial grammar test (AGT) is developed and N400 and P600 peaks are taken as indicators of performance; and two different groups of subjects took the AGT, 5 monolinguals and 5 bilinguals.The AGT is composed by 30 hybrids, each hybrid defines rules to formulate words; then if this word accomplished the rules, it is considered as grammatical. The N400 and P600 waves are computed by each word letter, and the mean for all 30 hybrids is compared between both two groups by electrode.Greater amplitudes for N400 and P600 peaks was found for monolinguals in comparison with bilinguals.