RESUMO
Sentence processing is affected by the sentence context and word expectancy. To investigate sentence comprehension experimentally, it is useful to have sentence completion norms with both context constraint and word expectancy measures. In this study, two experiments were conducted to collect norms for completion of 807 European Portuguese sentences. Context constraint was measured through type-token ratio and proportion idiosyncratic responses, while word expectancy was assessed by cloze probability. Besides establishing norms for a large sample of sentences, the study investigated the impact of the production procedure and method of analysis. In Experiment 1, a single-production procedure was used, i.e., participants completed each sentence fragment with only a single response, whereas in Experiment 2, a multiple-production procedure was used, i.e., participants have to provide up to three completion words for each sentence fragment. In Experiment 2, the analyses were obtained using two distinct methods: first-response analysis and combined-response analysis. The results showed that cloze and context measures are comparable between production paradigms and that the results from both analysis methods were correlated. The advantages of each production procedure and analysis method are discussed.
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Previous findings indicate that reducing brain insulin-like growth factor I receptor (IGF-IR) activity promotes ample neuroprotection. We now examined a possible action of IGF-IR on brain glucose transport to explain its wide protective activity, as energy availability is crucial for healthy tissue function. Using (18) FGlucose PET we found that shRNA interference of IGF-IR in mouse somatosensory cortex significantly increased glucose uptake upon sensory stimulation. In vivo microscopy using astrocyte specific staining showed that after IGF-IR shRNA injection in somatosensory cortex, astrocytes displayed greater increases in glucose uptake as compared to astrocytes in the scramble-injected side. Further, mice with the IGF-IR knock down in astrocytes showed increased glucose uptake in somatosensory cortex upon sensory stimulation. Analysis of underlying mechanisms indicated that IGF-IR interacts with glucose transporter 1 (GLUT1), the main facilitative glucose transporter in astrocytes, through a mechanism involving interactions with the scaffolding protein GIPC and the multicargo transporter LRP1 to retain GLUT1 inside the cell. These findings identify IGF-IR as a key modulator of brain glucose metabolism through its inhibitory action on astrocytic GLUT1 activity. GLIA 2016;64:1962-1971.
Assuntos
Astrócitos/metabolismo , Glucose/metabolismo , Fator de Crescimento Insulin-Like I/metabolismo , 4-Cloro-7-nitrobenzofurazano/análogos & derivados , 4-Cloro-7-nitrobenzofurazano/farmacologia , Animais , Animais Recém-Nascidos , Biotinilação , Encéfalo/citologia , Encéfalo/diagnóstico por imagem , Células Cultivadas , Proteína Glial Fibrilar Ácida/genética , Proteína Glial Fibrilar Ácida/metabolismo , Glucosamina/análogos & derivados , Glucosamina/farmacologia , Transportador de Glucose Tipo 1/metabolismo , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Fator de Crescimento Insulin-Like I/deficiência , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Estimulação Física , Transporte Proteico/genética , RNA Mensageiro/metabolismo , Transfecção , Vibrissas/fisiologiaRESUMO
Various noncanonical sentence constructions are derived from basic sentence structures by a phrase displacement called Movement. The moved phrase (filler) leaves a silent copy at the extracted position (gap) and is reactivated when the hearer/reader passes over the gap. Consequently, memory operations are assumed to occur to establish the filler-gap link. For languages that have a relatively free word order like German, a distinct linguistic operation called Scrambling is proposed. Although Movement and Scrambling are assumed to be different linguistic operations, they both involve memory prone filler-gap processes. To clarify whether filler-gap memory processes in Scrambling and Movement differ neuroanatomically, we designed a functional magnetic resonance imaging study and compared the effect of memory load parameterized by filler-gap distance in the 2 sentence types. Here, we show that processing of the 2 sentence types commonly relies on a left hemispheric network consisting of the inferior frontal gyrus, middle part of the middle temporal gyrus, and intraparietal sulcus. However, we found differences for the 2 sentence types in the linearity of filler-gap distance effect. Thus, the present results suggest that the same neural substrate supports the memory processes of sentences constructed by Movement and Scrambling, although differentially modulated by memory load.
Assuntos
Mapeamento Encefálico , Compreensão/fisiologia , Lobo Frontal/fisiologia , Idioma , Percepção da Fala/fisiologia , Adulto , Feminino , Humanos , Interpretação de Imagem Assistida por Computador , Linguística , Imageamento por Ressonância Magnética , Masculino , Estimulação Luminosa , Adulto JovemRESUMO
Disrupted GABAergic neurons have been extensively described in brain tissues from individuals with autism spectrum disorder (ASD) and animal models for ASD. However, the contribution of these aberrant inhibitory neurons to autism-related behavioral phenotypes is not well understood. We examined ASD-related behaviors in mice with conditional Pten knockout in parvalbumin (PV)-expressing or somatostatin (Sst)-expressing neurons, two common subtypes of GABAergic neurons. We found that mice with deletion of Pten in either PV-neurons or Sst-neurons displayed social deficits, repetitive behaviors and impaired motor coordination/learning. In addition, mice with one copy of Pten deletion in PV-neurons exhibited hyperlocomotion in novel open fields and home cages. We also examined anxiety behaviors and found that mice with Pten deletion in Sst-neurons displayed anxiety-like behaviors, while mice with Pten deletion in PV-neurons exhibited anxiolytic-like behaviors. These behavioral assessments demonstrate that Pten knockout in the subtype of inhibitory neurons sufficiently gives rise to ASD-core behaviors, providing evidence that both PV- and Sst-neurons may play a critical role in ASD symptoms.
Assuntos
Transtorno Autístico/metabolismo , Comportamento Animal , Neurônios/metabolismo , PTEN Fosfo-Hidrolase/deficiência , Parvalbuminas/metabolismo , Somatostatina/metabolismo , Animais , Ansiedade/complicações , Transtorno Autístico/complicações , Asseio Animal , Camundongos Endogâmicos C57BL , Camundongos Knockout , Atividade Motora , PTEN Fosfo-Hidrolase/metabolismo , Fenótipo , Comportamento SocialRESUMO
The current fMRI adaptation study sought to elucidate the dimensions of syntactic complexity and their underlying neural substrates. For the first time with fMRI, we investigated repetition suppression (i.e., fMRI adaptation) for two orthogonal dimensions of sentence complexity: embedding position (right-branching vs. center-embedding) and movement type (subject vs. object). Two novel results were obtained: First, we found syntactic adaptation in Broca's area and second, this adaptation was structured. Anterior Broca's area (BA 45) selectively adapted to movement type, while posterior Broca's area (BA 44) demonstrated adaptation to both movement type and embedding position (as did left posterior superior temporal gyrus and right inferior precentral sulcus). The functional distinction within Broca's area is critical not only to an understanding of the functional neuroanatomy of language, but also to theoretical accounts of syntactic complexity, demonstrating its multi-dimensional nature. These results implicate that during syntactic comprehension, a large network of areas is engaged, but that only anterior Broca's area is selective to syntactic movement.
Assuntos
Adaptação Fisiológica/fisiologia , Imageamento por Ressonância Magnética/métodos , Psicolinguística/métodos , Estimulação Acústica , Adulto , Comportamento/fisiologia , Córtex Cerebral/anatomia & histologia , Córtex Cerebral/fisiologia , Feminino , Lobo Frontal/anatomia & histologia , Lobo Frontal/fisiologia , Humanos , Processamento de Imagem Assistida por Computador , Idioma , Masculino , Pessoa de Meia-Idade , Movimento , Oxigênio/sangue , Estimulação Luminosa , Leitura , Adulto JovemRESUMO
Platinum is a promising candidate for the realization of blocking electrical contacts on cadmium-zinc-telluride (CdZnTe or CZT) radiation detectors. However, the poor mechanical adhesion of this metal often shortens the lifetime of the final device. In this work, a simple and effective procedure to obtain robust platinum contacts by electroless deposition is presented. Microscopical analysis revealed the final thickness and composition of the contact layer and its adhesion to the bulk crystal. The blocking nature of the Pt-CdZnTe junction, essential to obtain low noise devices, was confirmed by current-voltage measurements. The planar Pt-CdZnTe-Pt detectors showed good room temperature spectroscopic performance with energy resolution of 4% (2.4 keV) and 3% (3.7 keV) FWHM at 59.5 and 122.1 keV, respectively. Finally, we showed, for the first time, that platinum contacts allow the estimation of the carrier lifetime and mobility of both holes and electrons by using current transient measurements. This demonstrated the optimal hole extraction capability of such contacts.
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The intense effort to characterize Broca's region has produced many views on its anatomy and function. Here, we present the leading approaches and consider ways to adjudicate among them empirically. Anatomically, we focus on the cytoarchitecture of Brodmann areas 44 and 45, which constitute Broca's region. Functionally, we discuss four views: action perception, working memory, syntactic complexity and syntactic movement. We compare these views, reflect on how they can be distinguished experimentally and review relevant aphasia and functional magnetic resonance imaging (fMRI) studies. Although no single hypothesis accounts for all of the data, the role of Broca's region in language comprehension is best explained by the syntactic movement account. This conclusion opens the door for an attempt to define general principles for the neural representation of linguistic knowledge.
Assuntos
Afasia de Broca/fisiopatologia , Lobo Frontal/fisiopatologia , Mapeamento Encefálico , Humanos , Idioma , Imageamento por Ressonância Magnética , Memória de Curto Prazo/fisiologia , Percepção de Movimento/fisiologia , Psicolinguística , Leitura , Semântica , Percepção da Fala , Comportamento Verbal/fisiologiaRESUMO
Increasing evidence supports the notion that Alzheimer's disease (AD), a condition that presents heterogeneous pathological disturbances, is also associated to perturbed metabolic function affecting insulin and insulin-like growth factor I (IGF-I). While impaired insulin activity leading to insulin resistance has been associated to AD, whether altered IGF-I function affects the disease is not entirely clear. Despite the limitations of mouse models to mimic AD pathology, we took advantage that serum IGF-I deficient mice (LID mice) present many functional perturbations present in AD, most prominently cognitive loss, which is reversed by treatment with systemic IGF-I. We analyzed whether these mice display other pathological traits that are usual co-morbidities of AD. We found that LID mice not only display cognitive disturbances, but also show altered mood and sociability, increased susceptibility to epileptiform activity, and a disturbed sleep/wake cycle. Collectively, these data suggest that reduced IGF-I activity contributes to heterogeneous deficits commonly associated to AD. We suggest that impaired IGF-I activity needs to be taken into consideration when modeling this condition.
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Doença de Alzheimer/etiologia , Fator de Crescimento Insulin-Like I/deficiência , Doença de Alzheimer/complicações , Animais , Transtornos Cognitivos/complicações , Modelos Animais de Doenças , Feminino , Humanos , Fator de Crescimento Insulin-Like I/análise , Masculino , Aprendizagem em Labirinto , Camundongos , Camundongos Endogâmicos C57BL , Transtornos do Humor/complicações , Comportamento SocialRESUMO
BACKGROUND: Despite the benefits of aerobic exercise on body composition, runners with high body mass index (BMI) remain understudied. We examined body composition differences between sedentary insulin-resistant [obese insulin-resistant sedentary (OS-IR)], sedentary insulin-sensitive [obese insulin-sensitive sedentary (OS-IS)], and trained [obese trained (OT)] individuals with high BMI (≥25 kg/m2). We hypothesized that after matching for high BMI, OT individuals would have less fat mass (absolute and relative) and greater lean mass than OS-IR or OS-IS individuals. METHODS: This is a retrospective analysis of OS-IR, OS-IS, and OT participants selected for similar age, sex, and BMI. Activity was self-reported. OT participants exercised at least 30 min/day (predominantly running) for 3-5 days/week. OS-IS and OS-IR participants actively exercised <0.5 hr/week. Body composition was measured by dual X-ray absorptiometry. RESULTS: Thirty-three participants were recruited [n = 11/group, mean age 31.7 years (standard error): (0.9)], 7 females/group, overall BMI [31.6 kg/m2 (0.7)]. Insulin resistance, quantified by the homeostatic model assessment for insulin resistance, was higher in the OS-IR [3.3 (0.2)] than the OS-IS [0.9 (0.2): P < 0.0001] or OT [1.6 (0.2): P < 0.0001] groups. We found the following: (i) Compared to the OS-IR group, the OT group had lower region-specific fat mass as measured by percent fat (trunk) or absolute fat mass (trunk, android region, and abdominal visceral region). (ii) OT and OS-IS groups had similar body composition. (iii) Total fat mass and percent body fat correlated with BMI, (iv) Visceral fat correlated with BMI (r = 0.80, P = 0.003) only in the OS-IR (P = 0.03 for BMI × group interaction). CONCLUSIONS: Using BMI to classify obesity masks body composition differences in high BMI individuals discrepant for insulin resistance and physical activity status.
Assuntos
Composição Corporal , Índice de Massa Corporal , Exercício Físico , Estilo de Vida Saudável , Obesidade/diagnóstico , Comportamento Sedentário , Absorciometria de Fóton , Adiposidade , Adulto , Biomarcadores/sangue , Glicemia/metabolismo , Feminino , Humanos , Insulina/sangue , Resistência à Insulina , Masculino , Obesidade/sangue , Obesidade/fisiopatologia , Valor Preditivo dos Testes , Reprodutibilidade dos Testes , Estudos RetrospectivosRESUMO
Brain activity requires a flux of glucose to active regions to sustain increased metabolic demands. Insulin, the main regulator of glucose handling in the body, has been traditionally considered not to intervene in this process. However, we now report that insulin modulates brain glucose metabolism by acting on astrocytes in concert with IGF-I. The cooperation of insulin and IGF-I is needed to recover neuronal activity after hypoglycemia. Analysis of underlying mechanisms show that the combined action of IGF-I and insulin synergistically stimulates a mitogen-activated protein kinase/protein kinase D pathway resulting in translocation of GLUT1 to the cell membrane through multiple protein-protein interactions involving the scaffolding protein GAIP-interacting protein C terminus and the GTPase RAC1. Our observations identify insulin-like peptides as physiological modulators of brain glucose handling, providing further support to consider the brain as a target organ in diabetes.
Assuntos
Astrócitos/metabolismo , Glucose/metabolismo , Animais , Transporte Biológico/fisiologia , Transportador de Glucose Tipo 1/metabolismo , Glicogênio/metabolismo , Imunoensaio , Insulina/metabolismo , Fator de Crescimento Insulin-Like I/metabolismo , Ácido Láctico/metabolismo , Masculino , Camundongos , Neurônios/metabolismo , Plasmídeos , Reação em Cadeia da Polimerase , Tomografia por Emissão de PósitronsRESUMO
For decades concept typicality has been recognized as critical to structuring conceptual knowledge, but only recently has typicality been applied in better understanding the processes engaged by the neurological network underlying semantic memory. This previous work has focused on one region within the network - the Anterior Temporal Lobe (ATL). The ATL responds negatively to concept typicality (i.e., the more atypical the item, the greater the activation in the ATL). To better understand the role of typicality in the entire network, we ran an fMRI study using a category verification task in which concept typicality was manipulated parametrically. We argue that typicality is relevant to both amodal feature integration centers as well as category-specific regions. Both the Inferior Frontal Gyrus (IFG) and ATL demonstrated a negative correlation with typicality, whereas inferior parietal regions showed positive effects. We interpret this in light of functional theories of these regions. Interactions between category and typicality were not observed in regions classically recognized as category-specific, thus, providing an argument against category specific regions, at least with fMRI.
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Encéfalo/fisiologia , Formação de Conceito/fisiologia , Memória/fisiologia , Semântica , Adolescente , Adulto , Mapeamento Encefálico , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Vias Neurais/fisiologia , Testes Neuropsicológicos , Tempo de Reação , Adulto JovemRESUMO
Mood homeostasis present sexually dimorphic traits which may explain sex differences in the incidence of mood disorders. We explored whether diverse behavioral-setting components of mood may be differentially regulated in males and females by exercise, a known modulator of mood. We found that exercise decreases anxiety only in males. Conversely, exercise enhanced resilience to stress and physical arousal, two other important components of mood, only in females. Because exercise increases brain input of circulating insulin-like growth factor I (IGF-I), a potent modulator of mood, we explored whether sex-specific actions of exercise on mood homeostasis relate to changes in brain IGF-I input. We found that exercise increased hippocampal IGF-I levels only in cycling females. Underlying mechanism involved activation of estrogen (E2) receptors in brain vessels that led to increased uptake of serum IGF-I as E2 was found to stimulate IGF-I uptake in brain endothelial cells. Indeed, modulatory effects of exercise on mood were absent in female mice with low serum IGF-I levels or after either ovariectomy or administration of an E2 receptor antagonist. These results suggest that sex-specific brain IGF-I responses to physiological stimuli such as exercise contribute to dimorphic mood homeostasis that may explain sex differences in affective disorders.
Assuntos
Encéfalo/metabolismo , Estradiol/metabolismo , Fator de Crescimento Insulin-Like I/metabolismo , Transtornos do Humor/metabolismo , Animais , Células Cultivadas , Modelos Animais de Doenças , Exercício Físico , Feminino , Humanos , Masculino , Camundongos , Receptores de Estrogênio/metabolismo , Resiliência Psicológica , Caracteres SexuaisRESUMO
Grillo and Costa (2014) claim that Relative-Clause attachment ambiguity resolution is largely dependent on whether or not a Pseudo-Relative interpretation is available. Data from Italian, and other languages allowing Pseudo-Relatives, support this hypothesis. Pseudo-Relative availability, however, covaries with the semantics of the main predicate (e.g., perceptual vs. stative). Experiment 1 assesses whether this predicate distinction alone can account for prior attachment results by testing it with a language that disallows Pseudo-Relatives (i.e. English). Low Attachment was found independent of Predicate-Type. Predicate-Type did however have a minor modulatory role. Experiment 2 shows that English, traditionally classified as a Low Attachment language, can demonstrate High Attachment with sentences globally ambiguous between a Small-Clause and a reduced Relative-Clause interpretation. These results support a grammatical account of previous effects and provide novel evidence for the parser's preference of a Small-Clause over a Restrictive interpretation, crosslinguistically.
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Idioma , Linguística , Humanos , LeituraRESUMO
Behavioral studies of sentence comprehension suggest that processing long-distance dependencies is subject to interference effects when Noun Phrases (NP) similar to the dependency head intervene in the dependency. Neuroimaging studies converge in localizing such effects to Broca's area, showing that activity in Broca's area increases with the number of NP interveners crossed by a moved NP of the same type. To test if NP interference effects are modulated by adding an intervening clause boundary, which should by hypothesis increase the number of successive-cyclic movements, we conducted an fMRI study contrasting NP interveners with clausal (CP) interveners. Our design thus had two components: (I) the number of NP interveners crossed by movement was parametrically modulated; (II) CP-intervention was contrasted with NP-intervention. The number of NP interveners parametrically modulated a cluster straddling left BA44/45 of Broca's area, replicating earlier studies. Adding an intervening clause boundary did not significantly modulate the size of the NP interference effect in Broca's area. Yet, such an interaction effect was observed in the Superior Frontal Gyrus (SFG). Therefore, the involvement of Broca's area in processing syntactic movement is best captured by memory mechanisms affected by a grammatically instantiated type-identity (i.e., NP) intervention.
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Recent research has suggested that lateralization of aggressive behaviors could follow an homogeneous pattern among all vertebrates. A left eye/right hemisphere dominance in eliciting aggressive responses has been demonstrated for all groups of tetrapods but teleost fish for which data is lacking. Here we studied differential eye use during aggressive interactions in three species of teleosts: Gambusia holbrooki, Xenotoca eiseni and Betta splendens. In the first experiment we checked for lateralization in the use of the eyes while the subject was attacking its own mirror image. In order to confirm the results, other tests were performed on two species and eye preference was scored during attacks or displays directed toward a live rival. All three species showed a marked preference for using the right eye when attacking a mirror image or a live rival. Thus, the direction of asymmetry in fish appears the opposite to that shown by all the other groups of vertebrates. Hypotheses on the origin of the difference are discussed.
Assuntos
Agressão/fisiologia , Peixes/fisiologia , Lateralidade Funcional/fisiologia , Animais , Ciprinodontiformes/fisiologia , Masculino , Especificidade da EspécieRESUMO
Tadpoles of five anuran species were tested for preferences in the use of the eyes during inspection of their own visual image in a mirror. When tested in a tank with several small mirrors, tadpoles of five different species (Bufo bufo, Bufo viridis, Rana temporaria, Rana esculenta, Bombina variegata) preferentially approached and positioned themselves with the mirror located on their left side, thus looking at the image with the monocular field of their left eye. Similar results were obtained with tadpoles of R. temporaria tested in a simple task in which they had to choose approaching one or other of two large mirrors located on their left and right side. Control experiment showed that the behavioural asymmetry was not due to motor preferences and that it was independent of morphological asymmetries in the positions of the spiracles. This is the first demonstration of a functional visual lateralisation among juvenile amphibia before metamorphosis.
Assuntos
Anuros/fisiologia , Lateralidade Funcional/fisiologia , Larva/fisiologia , Comportamento Social , Meio Social , Animais , Bufonidae , Iluminação , Atividade Motora/fisiologia , Ranidae , Especificidade da EspécieRESUMO
The aversive properties of naloxone-precipitated morphine withdrawal from acutely administered morphine were assessed following a single conditioning trial using both the place conditioning and the taste conditioning paradigm. In both paradigms, the aversive properties of naloxone-precipitated morphine withdrawal were evident up to 48 h after a single injection of morphine. In neither paradigm did naloxone treatment alone produce an aversion after a single conditioning trial. These results suggest that a single morphine exposure produces long-lasting effects that persist at least 48 h beyond the agonist effects of the opiate.
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Aprendizagem da Esquiva/efeitos dos fármacos , Condicionamento Psicológico/efeitos dos fármacos , Dependência de Morfina , Morfina/administração & dosagem , Paladar/efeitos dos fármacos , Animais , Aprendizagem da Esquiva/fisiologia , Condicionamento Psicológico/fisiologia , Masculino , Naloxona/farmacologia , Ratos , Ratos Sprague-Dawley , Paladar/fisiologia , Fatores de TempoRESUMO
The current rapid event-related fMRI study used optional parasitic-gap constructions, such as [Which paper] did the tired student submit [(gap)--] after reviewing [(p-gap)--/it]?, to test 3 potential roles for Broca's area in sentence processing. These 3 functional options are: I. any intra-sentential Dependency relation activates Broca's area. II. This region specifically processes syntactic Displacement or movement. III. Broca's area handles any dependency relation, as long as it is predictable at an early stage of processing. Broca's area was only activated by the contrast that tested predictability within BA 45, as determined by its overlap with cytoarchitectonic probability maps. These results imply that an alternative or modified functional account of Broca's area, from those presently available, is required. Constraints on either a displacement account to movements that are not parasitic or a Working Memory one to predicted dependencies that cross verbal arguments or noun phrases would achieve the necessary consistency. Further, the results from the minimal contrasts investigating displacement and dependency have implications to potential language regions outside of Broca's area. The minimal contrast investigating displacement activated the left anterior Middle Temporal Gyrus, which has more recently been claimed to play a role in syntactic operations.
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Mapeamento Encefálico , Compreensão/fisiologia , Lobo Frontal/fisiologia , Lateralidade Funcional/fisiologia , Idioma , Adulto , Feminino , Lobo Frontal/irrigação sanguínea , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Memória de Curto Prazo , Oxigênio/sangue , Valor Preditivo dos Testes , Probabilidade , Psicolinguística , Adulto JovemRESUMO
Comprehension of filler-gap dependency relations (as in this is the man who the woman is touching) is supported by Broca's area. There are two views regarding the processing role of this brain region in comprehending these dependencies. Specifists hold that Broca's area plays a specific syntactic role in processing filler-gaps. Generalists maintain that as the on-line linking of fillers and gaps taxes Working Memory (WM) resources, Broca's area supports a domain general WM. The current fMRI study tested these two views in a grammaticality judgment task, where participants were presented with two syntactically distinct dependency relations: (a) Filler-Gap and (b) Reflexive Binding. The distance between the dependent elements within each of the constructions was varied, to parametrically vary WM demands. The Generalists would expect parametric variation of distance in both dependencies to lead to a linear increase in activation of Broca's area. Our results support the specifists' view, however: the left inferior frontal gyrus demonstrated an interaction between distance and dependency type with a positive linear effect only for Filler-Gaps. A positive linear effect of distance across both dependencies was only found in the bilateral parahippocampal/fusiform gyri. Therefore the role of Broca's area in WM is syntactically specific to filler-gap relations.
Assuntos
Compreensão/fisiologia , Lobo Frontal/fisiologia , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Memória de Curto Prazo/fisiologia , Semântica , Adulto , Mapeamento Encefálico , Dominância Cerebral/fisiologia , Feminino , Humanos , Modelos Lineares , Masculino , Tempo de Reação/fisiologia , Percepção da Fala/fisiologiaRESUMO
Motivated by claims that relegate the syntactic functions of Broca's region to working memory (WM) and not to language-specific mechanisms, we conducted an fMRI and an aphasia study that featured two varieties of intrasentential dependency relations: One was syntactic movement (e.g., Which boy does the girl think [symbol in text] examined Steven?), the other was antecedent-reflexive binding (e.g., Jill thinks the boy examined himself). In both, WM is required to link two nonadjacent positions. Syntactically, they are governed by distinct rule systems. In health, the two dependencies modulated activity in distinct brain regions within the left inferior frontal gyrus and the left middle temporal gyrus. Binding uniquely modulated activation in the right frontal lobe. Receptive abilities in brain damaged patients likewise distinguished among these syntactic types. The results indicate that sentence comprehension is governed by syntactically carved neural chunks and provide hints regarding a language related region in the right hemisphere.