RESUMO
Damage to the posterior language area (PLA), or Wernicke's area causes cortical reorganization in the corresponding regions of the contralateral hemisphere. However, the details of reorganization within the ipsilateral hemisphere are not fully understood. In this context, direct electrical stimulation during awake surgery can provide valuable opportunities to investigate neuromodulation of the human brain in vivo, which is difficult through the non-invasive approaches. Thus, in this study, we aimed to investigate the characteristics of the cortical reorganization of the PLA within the ipsilateral hemisphere. Sixty-two patients with left hemispheric gliomas were divided into groups depending on whether the lesion extended to the PLA. All patients underwent direct cortical stimulation with a picture-naming task. We further performed functional connectivity analyses using resting-state functional magnetic resonance imaging (MRI) in a subset of patients and calculated betweenness centrality, an index of the network importance of brain areas. During direct cortical stimulation, the regions showing positive (impaired) responses in the non-PLA group were localized mainly in the posterior superior temporal gyrus (pSTG), whereas those in the PLA group were widely distributed from the pSTG to the posterior supramarginal gyrus (pSMG). Notably, the percentage of positive responses in the pSMG was significantly higher in the PLA group (47%) than in the non-PLA group (8%). In network analyses of functional connectivity, the pSMG was identified as a hub region with high betweenness centrality in both the groups. These findings suggest that the language area can spread beyond the PLA to the pSMG, a hub region, in patients with lesion progression to the pSTG. The change in the pattern of the language area may be a compensatory mechanism to maintain efficient brain networks.
Assuntos
Neoplasias Encefálicas , Imageamento por Ressonância Magnética , Rede Nervosa , Área de Wernicke , Humanos , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/fisiopatologia , Masculino , Feminino , Pessoa de Meia-Idade , Adulto , Área de Wernicke/diagnóstico por imagem , Área de Wernicke/fisiopatologia , Área de Wernicke/fisiologia , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/fisiopatologia , Glioma/diagnóstico por imagem , Glioma/fisiopatologia , Glioma/cirurgia , Glioma/patologia , Estimulação Elétrica , Idoso , Idioma , Conectoma , Lobo Parietal/diagnóstico por imagem , Lobo Parietal/fisiopatologia , Mapeamento Encefálico , Adulto JovemRESUMO
Imaging and neurocognitive studies have searched for the brain areas involved in speech perception, specifically when speech is accompanied by noise, attempting to identify the underlying neural mechanism(s). Transcranial direct current stimulation (tDCS), a noninvasive, painless cortical neuromodulation technique, has been used to either excite or inhibit brain activity in order to better understand the neural mechanism underlying speech perception in noise. In the present study, anodal (excitatory) and cathodal (inhibitory) stimulations were performed on 48 participants, either over the left Inferior Frontal Gyrus (IFG), which includes Broca's area (n = 10 anodal, and n = 10 cathodal) or over the left Superior Temporal Gyrus (STG), which includes Wernicke's area (n = 13 anodal, n = 15 cathodal). Speech perception was measured using a sentence recognition task accompanied by white noise with a signal-to-noise ratio of -10 dB. Speech perception performance was measured four times: at baseline, after each of the two sessions of stimulation (one active and one sham session, the order of which was randomized between participants), and at a two-week follow-up session. Groups receiving anodal and cathodal stimulation over the left IFG did not show an effect of stimulation type. For groups receiving left STG stimulation, anodal stimulation resulted in higher scores, regardless of whether it was given before or after sham stimulation. However, cathodal stimulation showed an effect only when active stimulation was applied following sham stimulation. These results showed that tDCS had a direct effect on improving speech perception only over left STG. Furthermore, while anodal stimulation was effective in whatever order it was given, cathodal stimulation was effective only following sham stimulation, thereby allowing some amount of training. These findings carry both theoretical and clinical implications for the relationship between the DMN's left IFG and left STG areas during speech perception accompanied by background noise.
Assuntos
Área de Broca , Percepção da Fala , Lobo Temporal , Estimulação Transcraniana por Corrente Contínua , Humanos , Masculino , Percepção da Fala/fisiologia , Feminino , Adulto , Adulto Jovem , Área de Broca/fisiologia , Lobo Temporal/fisiologia , Córtex Pré-Frontal/fisiologia , Área de Wernicke/fisiologia , RuídoRESUMO
Numerous studies have shown robust evidence of the right hemisphere's involvement in the language function, for instance in the processing of intonation, grammar, word meanings, metaphors, etc. However, its role in lexicon acquisition remains obscure. We applied transcranial direct current stimulation (tDCS) over the right-hemispheric homologue of Wernicke's area to assess its putative involvement in the processing of different types of novel semantics. After receiving 15 min of anodal, cathodal, or sham (placebo) tDCS, three groups of healthy participants learnt novel concrete and abstract words in the context of short stories. Learning outcomes were assessed using a battery of tests immediately after this contextual learning session and 24 h later. As a result, an inhibitory effect of cathodal tDCS and a facilitatory effect of anodal tDCS were found for abstract word acquisition only. We also found a significant drop in task performance on the second day of the assessment for both word types in all the stimulation groups, suggesting no significant influence of tDCS on the post-learning consolidation of new memory traces. The results suggest an involvement of Wernicke's right-hemispheric counterpart in initial encoding (but not consolidation) of abstract semantics, which may be explained either by the right hemispheres direct role in processing lexical semantics or by an indirect impact of tDCS on contralateral (left-hemispheric) cortical areas through cross-callosal connections.
Assuntos
Estimulação Transcraniana por Corrente Contínua , Humanos , Estimulação Transcraniana por Corrente Contínua/métodos , Área de Wernicke/fisiologia , Idioma , Aprendizagem , SemânticaRESUMO
The Wernicke area, also known as Brodmann area 22, is located in the posterior segment of the superior temporal gyrus in the dominant hemisphere. Carl Wernicke, a German neurologist, described this area in 1874. The life story of Carl Wernicke, a 19th-century medical genius, remains an inspiration for all neuroscientists even a hundred years later. We outline Wernicke's life story and academic achievements in neurosurgery, neurology, and psychiatry. We explore his remarkable ability to turn his many setbacks into steps forward, his controversial foray into psychiatry, and his wide-ranging set of contributions, including his work on external ventricular drainage for hydrocephalus and encephalopathy; his description of the eponymous Wernicke area; and his field-defining work on aphasia. This historical review attempts to bring to life a seminal figure in the neurosciences, providing an insight into his visionary thought process.
Assuntos
Área de Wernicke , História do Século XIX , Humanos , História do Século XX , Área de Wernicke/anatomia & histologia , Alemanha , Neurocirurgia/história , Neurologia/história , Hidrocefalia/história , Hidrocefalia/cirurgiaRESUMO
The posterior superior temporal gyrus (pSTG) has been implicated in the integration of auditory feedback and motor system for controlling vocal production. However, the question as to whether and how the pSTG is causally involved in vocal feedback control is currently unclear. To this end, the present study selectively stimulated the left or right pSTG with continuous theta burst stimulation (c-TBS) in healthy participants, then used event-related potentials to investigate neurobehavioral changes in response to altered auditory feedback during vocal pitch regulation. The results showed that, compared to control (vertex) stimulation, c-TBS over the right pSTG led to smaller vocal compensations for pitch perturbations accompanied by smaller cortical N1 and larger P2 responses. Enhanced P2 responses received contributions from the right-lateralized temporal and parietal regions as well as the insula, and were significantly correlated with suppressed vocal compensations. Surprisingly, these effects were not found when comparing c-TBS over the left pSTG with control stimulation. Our findings provide evidence, for the first time, that supports a causal relationship between right, but not left, pSTG and auditory-motor integration for vocal pitch regulation. This lends support to a right-lateralized contribution of the pSTG in not only the bottom-up detection of vocal feedback errors but also the involvement of driving motor commands for error correction in a top-down manner.
Assuntos
Fala , Voz , Humanos , Fala/fisiologia , Área de Wernicke , Retroalimentação , Percepção da Altura Sonora/fisiologia , Voz/fisiologia , Retroalimentação Sensorial/fisiologia , Estimulação Acústica/métodosRESUMO
Context modulates sensory neural activations enhancing perceptual and behavioral performance and reducing prediction errors. However, the mechanism of when and where these high-level expectations act on sensory processing is unclear. Here, we isolate the effect of expectation absent of any auditory evoked activity by assessing the response to omitted expected sounds. Electrocorticographic signals were recorded directly from subdural electrode grids placed over the superior temporal gyrus (STG). Subjects listened to a predictable sequence of syllables, with some infrequently omitted. We found high-frequency band activity (HFA, 70-170 Hz) in response to omissions, which overlapped with a posterior subset of auditory-active electrodes in STG. Heard syllables could be distinguishable reliably from STG, but not the identity of the omitted stimulus. Both omission- and target-detection responses were also observed in the prefrontal cortex. We propose that the posterior STG is central for implementing predictions in the auditory environment. HFA omission responses in this region appear to index mismatch-signaling or salience detection processes.
Assuntos
Córtex Auditivo , Humanos , Córtex Auditivo/fisiologia , Área de Wernicke , Estimulação Acústica , Potenciais Evocados Auditivos/fisiologia , Mapeamento Encefálico , Percepção Auditiva/fisiologiaRESUMO
The spoken word does not fossilize. Despite this, scientists have long sought to unearth the origins of language within the human lineage. One of the lines of evidence they have pursued is functional brain areas, such as Broca's and Wernicke's areas, which are associated with speech production and comprehension, respectively. Sulcal layout of Broca's area clearly differs between humans and our closest living relatives, the chimpanzees, enabling its homolog in fossil hominins to be deemed more chimpanzee-like (i.e., closer to the ancestral form) or more human-like (i.e., derived form) with relative ease. Yet, no such differences have been found for Wernicke's area. This study compares sulcal and gyral organization of Wernicke's area across extant human brains (n=4), extant chimpanzee brains (n=5) and fossil hominin endocasts (n=4). Some chimpanzee brains had indications of leftward Wernicke's area asymmetry in the form of a shorter Sylvian fissure and/or caudal superior temporal gyral bulging in the left hemisphere. Overlap between the superior and middle temporal sulci in human but not chimpanzee brains may be due to a relatively larger Wernicke's area in humans. Fragmentation of the main body of the superior temporal sulcus exclusively in human left hemispheres was ascribed to a leftward Wernicke's area asymmetry in this species. Endocast examination found that, while Paranthropus robustus exhibit human-like overlap between the superior and middle temporal sulci, Australopithecus africanus do not, although they do exhibit chimpanzee-like caudal superior temporal gyral bulging. Such findings signal, albeit loosely, a more human-like Wernicke's area in Paranthropus than Australopithecus.
Assuntos
Hominidae , Área de Wernicke , Animais , Humanos , Idioma , Encéfalo , Córtex Cerebral , Pan troglodytesRESUMO
Perinatal stroke affects child's language development and can change language lateralization. Language generation and comprehension tasks in functional magnetic resonance imaging were used to determine language lateralization in term born children with perinatal left-side arterial ischemic stroke (AIS) (nâ¯=â¯9, mean age (SD) 13.4 (3.1) y.) and periventricular venous infarction (PVI) (nâ¯=â¯12, 11.8 (2.8) y.), and in healthy right-handed controls (nâ¯=â¯30, 11.6 (2.6) y.). Lateralization index was calculated for the Broca and Wernicke areas and correlated with language and cognitive outcomes measured by the Kaufman Assessment Battery for Children II ed. Language outcome in children with perinatal stroke is poorer compared to healthy controls. Children with small AIS lesions and most children with PVI showed left-side language activation. Most children with large AIS lesions and one child with large PVI had language activation reorganized to the right hemisphere. Language reorganization to the unlesioned right hemisphere did not ensure normal language outcome.
Assuntos
Idioma , Acidente Vascular Cerebral , Criança , Feminino , Mãos , Humanos , Imageamento por Ressonância Magnética/métodos , Gravidez , Acidente Vascular Cerebral/complicações , Acidente Vascular Cerebral/diagnóstico por imagem , Área de WernickeRESUMO
An accumulating body of evidence suggests that transcranial direct current stimulation (tDCS) can be used to affect language processing, including word acquisition. There has been, however, no comprehensive study of effects of tDCS of the core language areas in relation to the main word-learning mechanisms. Two principal strategies have been posited as important for natural word acquisition: explicit encoding (EE) which relies on direct instructions and repetition of material, and fast mapping (FM) which operates implicitly, via context-based inference or deduction. We used anodal and cathodal tDCS of Broca's and Wernicke's areas to assess effects of stimulation site and polarity on novel word acquisition in both EE and FM regimes. 160 participants, divided into five groups, received 15 min of cathodal or anodal tDCS over one of the two areas or a sham (placebo) stimulation before learning eight novel words, presented ten times each in a short naturalistic audio-visual word-picture association session, fully counterbalanced across different learning regimes. The outcome of novel word acquisition was measured immediately after the training using a free recall task. The results showed elevated accuracy in all real stimulation groups in comparison with sham stimulation; however, this effect only reached full significance after anodal tDCS of Broca's area. Comparisons between the two learning modes indicated that Broca's anodal tDCS significantly improved both implicit and explicit acquisition of novel vocabulary in comparison with sham tDCS, without, however, any significant differences between EE and FM regimes as such. The results indicate involvement of the left inferior-frontal neocortex in the learning of novel vocabulary and suggest a possibility to promote different types of word acquisition using anodal tDCS of this area.
Assuntos
Estimulação Transcraniana por Corrente Contínua , Área de Broca/fisiologia , Humanos , Estimulação Transcraniana por Corrente Contínua/métodos , Aprendizagem Verbal/fisiologia , Vocabulário , Área de WernickeRESUMO
Aim: This investigation aims to advance the understanding of neural dynamics that underlies live and natural interactions during spoken dialogue between two individuals. Introduction: The underlying hypothesis is that functional connectivity between canonical speech areas in the human brain will be modulated by social interaction. Methods: Granger causality was applied to compare directional connectivity across Broca's and Wernicke's areas during verbal conditions consisting of interactive and noninteractive communication. Thirty-three pairs of healthy adult participants alternately talked and listened to each other while performing an object naming and description task that was either interactive or not during hyperscanning with functional near-infrared spectroscopy (fNIRS). In the noninteractive condition, the speaker named and described a picture-object without reference to the partner's description. In the interactive condition, the speaker performed the same task but included an interactive response about the preceding comments of the partner. Causality measures of hemodynamic responses from Broca's and Wernicke's areas were compared between real, surrogate, and shuffled trials within dyads. Results: The interactive communication was characterized by bidirectional connectivity between Wernicke's and Broca's areas of the listener's brain. Whereas this connectivity was unidirectional in the speaker's brain. In the case of the noninteractive condition, both speaker's and listener's brains showed unidirectional top-down (Broca's area to Wernicke's area) connectivity. Conclusion: Together, directional connectivity as determined by Granger analysis reveals bidirectional flow of neuronal information during dynamic two-person verbal interaction for processes that are active during listening (reception) and not during talking (production). Findings are consistent with prior contrast findings (general linear model) showing neural modulation of the receptive language system associated with Wernicke's area during a two-person live interaction. Impact statement The neural dynamics that underlies real-life social interactions is an emergent topic of interest. Dynamically coupled cross-brain neural mechanisms between interacting partners during verbal dialogue have been shown within Wernicke's area. However, it is not known how within-brain long-range neural mechanisms operate during these live social functions. Using Granger causality analysis, we show bidirectional neural activity between Broca's and Wernicke's areas during interactive dialogue compared with a noninteractive control task showing only unidirectional activity. Findings are consistent with an Interactive Brain Model where long-range neural mechanisms process interactive processes associated with rapid and spontaneous spoken social cues.
Assuntos
Área de Broca , Área de Wernicke , Adulto , Encéfalo , Mapeamento Encefálico , Humanos , IdiomaRESUMO
Determining the impact that the KIAA0319 gene has on primate brain morphology can provide insight into the evolution of human cognition and language systems. Here, we tested whether polymorphisms in KIAA0319 in chimpanzees account for gray matter volumetric variation in brain regions implicated in language and communication (particularly within the posterior superior temporal gyrus and inferior frontal gyrus). First, we identified the nature and frequencies of single nucleotide variants (SNVs) in KIAA0319 in a sample of unrelated chimpanzees (Pan troglodytes spp.). Next, we genotyped a subset of SNVs (those important for gene regulation or likely to alter protein structure/function) in a sample of chimpanzees for which in vivo T1-structural magnetic resonance imaging scans had been obtained. We then used source-based morphometry (SBM) to test for whole-brain gray matter covariation differences between chimpanzees with different KIAA0319 alleles. Finally, using histologic sections of 15 postmortem chimpanzee brains, we analyzed microstructural variation related to KIAA0319 polymorphisms in the posterior superior temporal cortex. We found that the SNVs were associated with variation in gray matter within several brain regions, including the posterior superior temporal gyrus (a region associated with language comprehension and production in humans). The microstructure analysis further revealed hemispheric differences in neuropil fraction, indicating that KIAA0319 expression may be involved in regulation of processes related to the formation and maintenance of synapses, dendrites, or axons within regions associated with communication.
Assuntos
Substância Cinzenta , Pan troglodytes , Animais , Encéfalo/diagnóstico por imagem , Córtex Cerebral , Substância Cinzenta/diagnóstico por imagem , Imageamento por Ressonância Magnética , Área de WernickeRESUMO
RATIONALE: We report on a patient whose arcuate fasciculus (AF) and corticobulbar tract (CBT) recovered following an infarct in the middle cerebral artery (MCA) territory, demonstrated on serial diffusion tensor tractography (DTT). PATIENT CONCERNS: The patient showed moderate conduction aphasia on the Western Aphasia Battery with an aphasia quotient of 46.5 (spontaneous speech: 35.0, auditory comprehension: 36.0, and naming: 53.1) at 1 month after onset. His aphasia improved with an aphasia quotient of 49 (spontaneous speech: 71.0, auditory comprehension: 52.0, and naming: 59.0) at 10 months after onset. DIAGNOSIS: A 44-year-old right-handed male patient presented with aphasia and quadriplegia, which occurred at the onset of an infarct in the left MCA territory. INTERVENTION: Diffusion tensor imaging data were acquired twice (1 month and 10 months after onset). OUTCOMES: On one-month DTT, the discontinuation of the left AF and severe narrowing of the right CBT were observed. However, on ten-month DTT, the left AF was connected to the opposite AF by a new tract that passed through the splenium of corpus callosum, and the right CBT had become thicker. LESSONS: We believe that our results suggest a recovery mechanism of injured AF and CBT in stroke patients.
Assuntos
Afasia , Encéfalo , Área de Broca , Infarto da Artéria Cerebral Média , Área de Wernicke , Adulto , Afasia/diagnóstico , Afasia/etiologia , Afasia/reabilitação , Encéfalo/irrigação sanguínea , Encéfalo/diagnóstico por imagem , Imagem de Tensor de Difusão/métodos , Humanos , Infarto da Artéria Cerebral Média/diagnóstico , Infarto da Artéria Cerebral Média/fisiopatologia , Infarto da Artéria Cerebral Média/reabilitação , Masculino , Vias Neurais/patologia , Vias Neurais/fisiopatologia , Reabilitação Neurológica/métodos , Tratos Piramidais/patologia , Recuperação de Função Fisiológica , Fonoterapia/métodos , Resultado do TratamentoRESUMO
OBJECTIVE: Patients with brain tumors frequently present neurocognitive deficits. Aiming at better understanding the impact of tumor localization on neurocognitive processes, we evaluated neurocognitive function prior to glioma surgery within one of four specific regions in the left speech-dominant hemisphere. METHODS: Between 04/2011 and 12/2019, 43 patients undergoing neurocognitive evaluation prior to awake surgery for gliomas (WHO grade I: 2; II: 6; III: 23; IV: 11) in the inferior frontal gyrus (IFG; n = 20), the anterior temporal lobe (ATL; n = 6), the posterior superior temporal region/supramarginal gyrus (pST/SMG; n = 7) or the posterior middle temporal gyrus (pMTG; n = 10) of the language dominant left hemisphere were prospectively included in the study. Cognitive performances were analyzed regarding an influence of patient characteristics and tumor localization. RESULTS: Severe impairment in at least one neurocognitive domain was found in 36 (83.7%) patients. Anxiety and depression were observed most frequently, followed by verbal memory impairments. Verbal memory was more strongly affected in patients with ATL or pST/SMG tumors compared to IFG tumors (p = 0.004 and p = 0.013, resp.). Overall, patients suffering from tumors in the ATL were most frequently and severely impaired. CONCLUSION: Patients suffering from gliomas involving different regions within the language dominant hemisphere frequently present impairments in neurocognitive domains also other than language. Considering individual functions at risk may help in better advising patients prior to treatment and in tailoring the individual therapeutic strategy to preserve patients' quality of life.
Assuntos
Neoplasias Encefálicas/patologia , Disfunção Cognitiva/etiologia , Disfunção Cognitiva/patologia , Glioma/patologia , Adolescente , Adulto , Idoso , Neoplasias Encefálicas/complicações , Feminino , Lateralidade Funcional , Glioma/complicações , Humanos , Masculino , Pessoa de Meia-Idade , Córtex Pré-Frontal/patologia , Lobo Temporal/patologia , Área de Wernicke/patologia , Adulto JovemRESUMO
BACKGROUND: Functional connectivity abnormalities between Broca's and Wernicke's areas and the putamen revealed by functional magnetic resonance imaging (fMRI) are related to auditory hallucinations (AH). In long-term schizophrenia, reduced white matter structural integrity revealed by diffusion imaging in left arcuate fasciculus (connecting Broca's and Wernicke's areas) is likely related to AH. The structural integrity of connections with putamen and their relation to AH are unknown. Little is known about this relationship in first-episode psychosis (FEP), although auditory transcallosal connections were reported to play a role. White matter in the Broca's-Wernicke's-putamen language-related circuit and auditory transcallosal fibers was examined to investigate associations with AH in FEP. METHODS: White matter connectivity was measured in 40 FEP and 32 matched HC using generalized fractional anisotropy (gFA) derived from diffusion spectrum imaging (DSI). RESULTS: FEP and HC did not differ in gFA in any fiber bundle. In FEP, AH severity was significantly inversely related to gFA in auditory transcallosal fibers and left arcuate fasciculus. Although the right hemisphere arcuate fasciculus-AH association did not attain significance, the left and right arcuate fasciculus associations were not significantly different. CONCLUSIONS: Despite overall normal gFA in FEP, AH severity was significantly related to gFA in transcallosal auditory fibers and the left hemisphere connection between Broca's and Wernicke's areas. Other bilateral tracts' gFA were weakly associated with AH. At the first psychotic episode, AH are more robustly associated with left hemisphere arcuate fasciculus and interhemispheric auditory fibers microstructural deficits, likely reflecting mistiming of information flow between language-related cortical centers.
Assuntos
Transtornos Psicóticos Afetivos/patologia , Percepção Auditiva , Área de Broca/patologia , Corpo Caloso/patologia , Alucinações/patologia , Transtornos Psicóticos/patologia , Putamen/patologia , Esquizofrenia/patologia , Área de Wernicke/patologia , Substância Branca/patologia , Adolescente , Adulto , Transtornos Psicóticos Afetivos/diagnóstico por imagem , Área de Broca/diagnóstico por imagem , Corpo Caloso/diagnóstico por imagem , Imagem de Difusão por Ressonância Magnética , Feminino , Alucinações/diagnóstico por imagem , Humanos , Masculino , Vias Neurais/diagnóstico por imagem , Vias Neurais/patologia , Transtornos Psicóticos/diagnóstico por imagem , Putamen/diagnóstico por imagem , Esquizofrenia/diagnóstico por imagem , Área de Wernicke/diagnóstico por imagem , Substância Branca/diagnóstico por imagem , Adulto JovemRESUMO
This study used structural magnetic resonance imaging to examine whether specific anatomical features of Broca's and Wernicke's areas are related to language functions in typically developing older subjects with no specific language expertize. Data from 231 subjects from the Zurich LHAB-study are used for this study. For these subjects, we obtained several psychometric measures from which we calculated performance measures reflecting specific psychological functions (language comprehension, verbal fluency, perceptual speed, visual memory, recognition of regularities, and logical thinking). From the MRI measurements, we calculated the cortical thickness and cortical surface of Broca's and Wernicke's areas. Applying multiple regression analyses, we identified a moderately strong relationship between language comprehension and the brain metrics from Broca's and Wernicke's areas and showed that approximately 10% of the variance in language comprehension performance is explained by the linear combination of all perisylvian brain metrics. The other psychological functions (verbal fluency, perceptual speed, visual memory, recognition of regularities, and logical thinking) are not related to these brain metrics. Subsequent detailed analyses revealed that the cortical thickness of Wernicke's area, in particular, contributed most to this structure-function relationship. The better performance in the language comprehension tests was related to a thicker cortex in Wernicke's area. Thus, this study demonstrates a structure-function relationship between the anatomical features of the perisylvian language areas and language comprehension, suggesting that particular anatomical features are associated with better language performance.
Assuntos
Idioma , Área de Wernicke , Encéfalo , Mapeamento Encefálico , Humanos , Imageamento por Ressonância Magnética , Área de Wernicke/diagnóstico por imagemRESUMO
BACKGROUND: Surgical resection of diffuse low-grade gliomas (DLGGs) involving cortical eloquent areas and subcortical functional pathways represents a challenge in neurosurgery. Patient-specific, 3-dimensional (3D)-printed models of head and brain structures have emerged in recent years as an educational and clinical tool for patients, doctors, and surgical residents. METHODS: Using multimodal high-definition magnetic resonance imaging data, which incorporates information from specific task-based functional neuroimaging and diffusion tensor imaging tractography and rapid prototyping technologies with specialized software and "in-house" 3D printing, we were able to generate 3D-printed head models that were used for preoperative patient education and consultation, surgical planning, and resident training in 2 complicated DLGG surgeries. RESULTS: This 3D-printed model is rapid prototyped and shows a means to model individualized, diffuse, low-level glioma in 3D space with respect to cortical eloquent areas and subcortical pathways. Survey results from 8 surgeons with different levels of expertise strongly support the use of this model for surgical planning, intraoperative surgical guidance, doctor-patient communication, and surgical training (>95% acceptance). CONCLUSIONS: Spatial proximity of DLGG to cortical eloquent areas and subcortical tracts can be readily assessed in patient-specific 3D printed models with high fidelity. 3D-printed multimodal models could be helpful in preoperative patient consultation, surgical planning, and resident training.
Assuntos
Astrocitoma/cirurgia , Neoplasias Encefálicas/cirurgia , Procedimentos Neurocirúrgicos/métodos , Adulto , Astrocitoma/diagnóstico por imagem , Astrocitoma/patologia , Mapeamento Encefálico , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/patologia , Área de Broca/diagnóstico por imagem , Imagem de Tensor de Difusão , Feminino , Neuroimagem Funcional , Glioma/diagnóstico por imagem , Glioma/patologia , Glioma/cirurgia , Humanos , Período Intraoperatório , Imageamento por Ressonância Magnética , Masculino , Modelos Anatômicos , Gradação de Tumores , Vias Neurais/diagnóstico por imagem , Procedimentos Neurocirúrgicos/educação , Educação de Pacientes como Assunto , Modelagem Computacional Específica para o Paciente , Impressão Tridimensional , Tratos Piramidais/diagnóstico por imagem , Vigília , Área de Wernicke/diagnóstico por imagem , Adulto JovemRESUMO
Word-production theories argue that during language production, a concept activates multiple lexical candidates in left temporal cortex, and the intended word is selected from this set. Evidence for theories on spoken-word production comes, for example, from the picture-word interference task, where participants name pictures superimposed by congruent (e.g., picture: rabbit, distractor "rabbit"), categorically related (e.g., distractor "sheep"), or unrelated (e.g., distractor "fork") words. Typically, whereas congruent distractors facilitate naming, related distractors slow down picture naming relative to unrelated distractors, resulting in semantic interference. However, the neural correlates of semantic interference are debated. Previous neuroimaging studies have shown that the left mid-to-posterior STG (pSTG) is involved in the interference associated with semantically related distractors. To probe the functional relevance of this area, we targeted the left pSTG with focal repetitive transcranial magnetic stimulation (rTMS) while subjects performed a picture-word interference task. Unexpectedly, pSTG stimulation did not affect the semantic interference effect but selectively increased the congruency effect (i.e., faster naming with congruent distractors). The facilitatory TMS effect selectively occurred in the more difficult list with an overall lower name agreement. Our study adds new evidence to the causal role of the left pSTG in the interaction between picture and distractor representations or processing streams, only partly supporting previous neuroimaging studies. Moreover, the observed unexpected condition-specific facilitatory rTMS effect argues for an interaction of the task- or stimulus-induced brain state with the modulatory TMS effect. These issues should be systematically addressed in future rTMS studies on language production.
Assuntos
Reconhecimento Visual de Modelos/fisiologia , Lobo Temporal/efeitos da radiação , Estimulação Magnética Transcraniana/métodos , Área de Wernicke/fisiologia , Adulto , Animais , Atenção/efeitos da radiação , Feminino , Humanos , Idioma , Reconhecimento Visual de Modelos/efeitos da radiação , Coelhos , Tempo de Reação/efeitos da radiação , Fala/efeitos da radiação , Área de Wernicke/efeitos da radiaçãoRESUMO
INTRODUCCIÓN: Los tumores neuroepiteliales disembrioplásicos (DNET) son un tipo de neoplasia glioneuronal benigna de localización típicamente temporal que producen crisis epilépticas resistentes al tratamiento farmacológico en niños y adultos jóvenes. OBJETIVO: Se muestran 4 casos valorando la utilidad de la resonancia magnética funcional en el estudio prequirúrgico de pacientes con tumores neuroepiteliales disembrionarios. Para la obtención de imágenes se utilizó un equipo de resonancia magnética Philipps Intera de 3.0 Tesla y la técnica Blood Oxygenation Level-Dependent, permitiendo localizar las áreas elocuentes de lenguaje y motora mediante la aplicación de paradigmas específicos. RESULTADOS: En un caso el tumor se encontraba adyacente al área de Broca, en 2 casos coincidía con Wernicke, en un paciente estaba menos de 1cm del área motora de la mano y en otro próximo a la memoria. Solo 2 de los pacientes fueron operados, no produciéndose déficit funcional postoperatorio. Se observó activación hemisférica contralateral al tumor sugestivo de neuroplasticidad en uno de los pacientes. CONCLUSIONES: La resonancia magnética funcional supone un método no invasivo que permite evaluar la proximidad de las lesiones a las áreas elocuentes, clave en la evaluación del riesgo quirúrgico. Además, ha permitido detectar probable neuroplasticidad en un caso, la cual ha garantizado el éxito de la cirugía
INTRODUCTION: Dysembryoplastic neuroepithelial tumours (DNET) are a type of benign glioneuronal neoplasia of typically temporal location that produce drug-resistant epileptic seizures in children and young adults. OBJECTIVE: This work aims to assess the usefulness of functional magnetic resonance imaging (fMRI) in the preoperative study in four patients with DNET. A Philips Intera 3.0 Tesla magnetic resonance imaging scanner and the Blood-Oxygen-Level-Dependent (BOLD) technique were used to obtain the images, making it possible to locate the eloquent areas for language and motor areas through the application of specific paradigms. RESULTS: In one case the tumour was adjacent to Broca's area, in two cases it coincided with Wernicke's area, in one patient it was < 1cm from the motor area for the hand and in another close to memory. Only two of the patients were operated on, without postoperative functional deficit. Hemispheric activation contralateral to the tumour suggestive of neuroplasticity was observed in one of the patients. CONCLUSIONS: fMRI is a non-invasive method that allows us to assess the proximity of lesions to eloquent areas, which is key in the evaluation of surgical risk. In addition, it allowed the detection of probable neuroplasticity in one case, which guaranteed the success of the surgery
Assuntos
Humanos , Neoplasias Neuroepiteliomatosas/diagnóstico por imagem , Neoplasias Neuroepiteliomatosas/fisiopatologia , Encefalopatias/patologia , Lateralidade Funcional/fisiologia , Neuroimagem Funcional/métodos , Imageamento por Ressonância Magnética/instrumentação , Área de Wernicke/diagnóstico por imagem , Encefalopatias/fisiopatologiaRESUMO
BACKGROUND: Although the safety and feasibility of awake craniotomy are well established for epilepsy and brain tumor surgery, its application for resection of vascular lesions, including arteriovenous malformations (AVMs) and cavernomas, is still limited. Apart from the usual challenges of awake craniotomy, vascular lesions pose several additional problems. Our goal is to determine the safety and practicality of awake craniotomy in patients with cerebral vascular malformations located near the eloquent areas, using a refined anesthetic protocol. METHODS: A retrospective case series was performed on 7 patients who underwent awake craniotomy for resection of AVMs or cavernomas located in the eloquent language and motor areas. Our protocol consisted of achieving deep sedation, without a definitive airway, using a combination of propofol, dexmedetomidine, and remifentanil/fentanyl during scalp block placement and surgical exposure, then transitioning to a wakeful state during the resection. RESULTS: Six patients had intracranial AVMs, and 1 patient had a cavernoma. Six patients had complete resection; however, 1 patient underwent repeat awake craniotomy for residual AVM nidus. The patients tolerated the resection under continuous awake neurologic and neurophysiologic testing without significant perioperative complications or the need to convert to general anesthesia with a definitive airway. CONCLUSIONS: Awake craniotomy for excision of intracranial vascular malformations located near the eloquent areas, in carefully selected patients, can facilitate resection by allowing close neuromonitoring and direct functional assessment. A balanced combination of sedative and analgesic medications can provide both adequate sedation and rapid wakeup, facilitating the necessary patient interaction and tolerance of the procedure.
Assuntos
Neoplasias Encefálicas/cirurgia , Área de Broca/cirurgia , Sedação Profunda/métodos , Hemangioma Cavernoso do Sistema Nervoso Central/cirurgia , Malformações Arteriovenosas Intracranianas/cirurgia , Córtex Motor/cirurgia , Procedimentos Neurocirúrgicos/métodos , Vigília , Área de Wernicke/cirurgia , Adolescente , Adulto , Analgésicos Opioides/uso terapêutico , Anestésicos Intravenosos/uso terapêutico , Neoplasias Encefálicas/diagnóstico por imagem , Angiografia Cerebral , Angiografia por Tomografia Computadorizada , Craniotomia/métodos , Dexmedetomidina/uso terapêutico , Feminino , Fentanila/uso terapêutico , Hemangioma Cavernoso do Sistema Nervoso Central/diagnóstico por imagem , Humanos , Hipnóticos e Sedativos/uso terapêutico , Malformações Arteriovenosas Intracranianas/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Bloqueio Nervoso/métodos , Propofol/uso terapêutico , Remifentanil/uso terapêutico , Adulto JovemRESUMO
The arcuate fasciculus (AF) has been implicated in the pathology behind schizophrenia and auditory verbal hallucinations (AVHs). White matter tracts forming the arcuate fasciculus can be quantified and visualized using diffusion tensor imaging (DTI) tractography. Although there have been a number of studies on this topic, the results have been conflicting. Studying the underlying white matter structure of the AF could shed light on the constrains for interaction between temporal and frontal language areas in AVHs. The participants were 66 patients with a schizophrenia diagnosis, where AVHs were defined from the Positive and Negative Syndrome Scale (PANSS), and compared with a healthy control group. DTI was performed on a 3T MR scanner, and tensor estimation was done using deterministic streamline tractography. Statistical analysis of the data showed significantly longer reconstructed tracks along the AF in patients with severe and frequent AVHs, as well as an overall significant asymmetry with longer tracks in the left compared to the right side. In addition, there were significant positive correlations between PANSS scores and track length, track volume, and number of track streamlines for the posterior AF segment on the left side. It is concluded that the present DTI results may have implications for interpretations of functional imaging results.