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1.
Neuropsychologia ; 195: 108815, 2024 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-38311112

RESUMO

Functional brain responses are strongly influenced by connectivity. Recently, we demonstrated a major example of this: category discriminability within occipitotemporal cortex (OTC) is enhanced for voxel sets that share strong functional connectivity to distal brain areas, relative to those that share lesser connectivity. That is, within OTC regions, sets of 'most-connected' voxels show improved multivoxel pattern discriminability for tool-, face-, and place stimuli relative to voxels with weaker connectivity to the wider brain. However, understanding whether these effects generalize to other domains (e.g. body perception network), and across different levels of the visual processing streams (e.g. dorsal as well as ventral stream areas) is an important extension of this work. Here, we show that this so-called connectivity-guided decoding (CGD) effect broadly generalizes across a wide range of categories (tools, faces, bodies, hands, places). This effect is robust across dorsal stream areas, but less consistent in earlier ventral stream areas. In the latter regions, category discriminability is generally very high, suggesting that extraction of category-relevant visual properties is less reliant on connectivity to downstream areas. Further, CGD effects are primarily expressed in a category-specific manner: For example, within the network of tool regions, discriminability of tool information is greater than non-tool information. The connectivity-guided decoding approach shown here provides a novel demonstration of the crucial relationship between wider brain connectivity and complex local-level functional responses at different levels of the visual processing streams. Further, this approach generates testable new hypotheses about the relationships between connectivity and local selectivity.


Assuntos
Imageamento por Ressonância Magnética , Lobo Temporal , Humanos , Lobo Temporal/fisiologia , Percepção Visual , Encéfalo/diagnóstico por imagem , Mapeamento Encefálico , Reconhecimento Visual de Modelos/fisiologia
2.
Sci Rep ; 14(1): 3757, 2024 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-38355712

RESUMO

Many species learn temporal regularities in their visual environment, demonstrating visual statistical learning. In this study, we explored the sensitivity of macaque inferior temporal (IT) cortical neurons to transition probabilities of sequentially presented visual images, presented at different locations in the visual field. We exposed monkeys to sequences of two images, where the first image was presented either foveally or peripherally, and the second image was consistently presented foveally. Following several weeks of exposure, we recorded IT responses to assess differences between the exposed (Fixed) and new, Deviant sequences, where the identity of the first image in a sequence differed from the exposure phase. While enhanced responses to Deviant sequences were observed when both images of a pair were foveally presented during exposure, no such deviant responses were present when the first image was presented peripherally. This finding challenges the notion that mere exposure to image sequences always leads to deviant responses in macaque IT. The results highlight the complexity of the mechanisms underlying statistical learning in primates, particularly in the context of peripheral image presentations, emphasizing the need for further investigation into the origins of these responses in the IT cortex.


Assuntos
Lobo Temporal , Campos Visuais , Animais , Macaca mulatta , Lobo Temporal/diagnóstico por imagem , Lobo Temporal/fisiologia , Neurônios/fisiologia , Estimulação Luminosa , Aprendizagem Espacial
3.
Hum Brain Mapp ; 45(2): e26603, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38339900

RESUMO

Reading, naming, and repetition are classical neuropsychological tasks widely used in the clinic and psycholinguistic research. While reading and repetition can be accomplished by following a direct or an indirect route, pictures can be named only by means of semantic mediation. By means of fMRI multivariate pattern analysis, we evaluated whether this well-established fundamental difference at the cognitive level is associated at the brain level with a difference in the degree to which semantic representations are activated during these tasks. Semantic similarity between words was estimated based on a word association model. Twenty subjects participated in an event-related fMRI study where the three tasks were presented in pseudo-random order. Linear discriminant analysis of fMRI patterns identified a set of regions that allow to discriminate between words at a high level of word-specificity across tasks. Representational similarity analysis was used to determine whether semantic similarity was represented in these regions and whether this depended on the task performed. The similarity between neural patterns of the left Brodmann area 45 (BA45) and of the superior portion of the left supramarginal gyrus correlated with the similarity in meaning between entities during picture naming. In both regions, no significant effects were seen for repetition or reading. The semantic similarity effect during picture naming was significantly larger than the similarity effect during the two other tasks. In contrast, several regions including left anterior superior temporal gyrus and left ventral BA44/frontal operculum, among others, coded for semantic similarity in a task-independent manner. These findings provide new evidence for the dynamic, task-dependent nature of semantic representations in the left BA45 and a more task-independent nature of the representational activation in the lateral temporal cortex and ventral BA44/frontal operculum.


Assuntos
Leitura , Semântica , Humanos , Mapeamento Encefálico , Lobo Temporal/diagnóstico por imagem , Lobo Temporal/fisiologia , Encéfalo , Imageamento por Ressonância Magnética
4.
Hum Brain Mapp ; 45(3): e26605, 2024 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-38379447

RESUMO

The lateral occipitotemporal cortex (LOTC) has been shown to capture the representational structure of a smaller range of actions. In the current study, we carried out an fMRI experiment in which we presented human participants with images depicting 100 different actions and used representational similarity analysis (RSA) to determine which brain regions capture the semantic action space established using judgments of action similarity. Moreover, to determine the contribution of a wide range of action-related features to the neural representation of the semantic action space we constructed an action feature model on the basis of ratings of 44 different features. We found that the semantic action space model and the action feature model are best captured by overlapping activation patterns in bilateral LOTC and ventral occipitotemporal cortex (VOTC). An RSA on eight dimensions resulting from principal component analysis carried out on the action feature model revealed partly overlapping representations within bilateral LOTC, VOTC, and the parietal lobe. Our results suggest spatially overlapping representations of the semantic action space of a wide range of actions and the corresponding action-related features. Together, our results add to our understanding of the kind of representations along the LOTC that support action understanding.


Assuntos
Lobo Occipital , Lobo Temporal , Humanos , Lobo Occipital/fisiologia , Lobo Temporal/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Mapeamento Encefálico/métodos , Estimulação Luminosa/métodos , Imageamento por Ressonância Magnética
6.
Hum Brain Mapp ; 45(1): e26569, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38224540

RESUMO

Successful visual word recognition requires the integration of phonological and semantic information, which is supported by the dorsal and ventral pathways in the brain. However, the functional specialization or interaction of these pathways during phonological and semantic processing remains unclear. Previous research has been limited by its dependence on correlational functional magnetic resonance imaging (fMRI) results or causal validation using patient populations, which are susceptible to confounds such as plasticity and lesion characteristics. To address this, the present study employed continuous theta-burst stimulation combined with fMRI in a within-subject design to assess rapid adaptation in regional activity and functional connectivity of the dorsal and ventral pathways during phonological and semantic tasks. This assessment followed the precise inhibition of the left inferior parietal lobule and anterior temporal lobe in the dorsal and ventral pathways, respectively. Our results reveal that both the dorsal and ventral pathways were activated during phonological and semantic processing, while the adaptation activation and interactive network were modulated by the task type and inhibited region. The two pathways exhibited interconnectivity in phonological processing, and disruption of either pathway led to rapid adaptation across both pathways. In contrast, only the ventral pathway exhibited connectivity in semantic processing, and disruption of this pathway alone resulted in adaptive effects primarily in the ventral pathway. These findings provide essential evidence supporting the interactive theory, phonological information processing in particular, potentially providing meaningful implications for clinical populations.


Assuntos
Imageamento por Ressonância Magnética , Semântica , Humanos , Imageamento por Ressonância Magnética/métodos , Mapeamento Encefálico/métodos , Encéfalo/diagnóstico por imagem , Encéfalo/fisiologia , Lobo Temporal/fisiologia
7.
Sci Data ; 11(1): 89, 2024 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-38238342

RESUMO

We present a dataset of 1809 single neurons recorded from the human medial temporal lobe (amygdala and hippocampus) and medial frontal lobe (anterior cingulate cortex, pre-supplementary motor area, ventral medial prefrontal cortex) across 41 sessions from 21 patients that underwent seizure monitoring with depth electrodes. Subjects performed a screening task (907 neurons) to identify images for which highly selective cells were present. Subjects then performed a working memory task (902 neurons), in which they were sequentially presented with 1-3 images for which highly selective cells were present and, following a maintenance period, were asked if the probe was identical to one of the maintained images. This Neurodata Without Borders formatted dataset includes spike times, extracellular spike waveforms, stimuli presented, behavior, electrode locations, and subject demographics. As validation, we replicate previous findings on the selectivity of concept cells and their persistent activity during working memory maintenance. This large dataset of rare human single-neuron recordings and behavior enables the investigation of the neural mechanisms of working memory in humans.


Assuntos
Memória de Curto Prazo , Córtex Motor , Humanos , Tonsila do Cerebelo/fisiologia , Memória de Curto Prazo/fisiologia , Córtex Motor/fisiologia , Neurônios/fisiologia , Lobo Temporal/fisiologia
8.
Neuroimage ; 287: 120520, 2024 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-38242489

RESUMO

The human ventral occipito-temporal cortex (VOTC) has evolved into specialized regions that process specific categories, such as words, tools, and animals. The formation of these areas is driven by bottom-up visual and top-down nonvisual experiences. However, the specific mechanisms through which top-down nonvisual experiences modulate category-specific regions in the VOTC are still unknown. To address this question, we conducted a study in which participants were trained for approximately 13 h to associate three sets of novel meaningless figures with different top-down nonvisual features: the wordlike category with word features, the non-wordlike category with nonword features, and the visual familiarity condition with no nonvisual features. Pre- and post-training functional MRI (fMRI) experiments were used to measure brain activity during stimulus presentation. Our results revealed that training induced a categorical preference for the two training categories within the VOTC. Moreover, the locations of two training category-specific regions exhibited a notable overlap. Remarkably, within the overlapping category-specific region, training resulted in a dissociation in activation intensity and pattern between the two training categories. These findings provide important insights into how different nonvisual categorical information is encoded in the human VOTC.


Assuntos
Aprendizagem , Lobo Temporal , Humanos , Lobo Temporal/diagnóstico por imagem , Lobo Temporal/fisiologia , Reconhecimento Psicológico , Imageamento por Ressonância Magnética/métodos , Mapeamento Encefálico/métodos , Reconhecimento Visual de Modelos/fisiologia , Estimulação Luminosa/métodos
9.
Cereb Cortex ; 34(2)2024 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-38183184

RESUMO

Auditory sensory processing is assumed to occur in a hierarchical structure including the primary auditory cortex (A1), superior temporal gyrus, and frontal areas. These areas are postulated to generate predictions for incoming stimuli, creating an internal model of the surrounding environment. Previous studies on mismatch negativity have indicated the involvement of the superior temporal gyrus in this processing, whereas reports have been mixed regarding the contribution of the frontal cortex. We designed a novel auditory paradigm, the "cascade roving" paradigm, which incorporated complex structures (cascade sequences) into a roving paradigm. We analyzed electrocorticography data from six patients with refractory epilepsy who passively listened to this novel auditory paradigm and detected responses to deviants mainly in the superior temporal gyrus and inferior frontal gyrus. Notably, the inferior frontal gyrus exhibited broader distribution and sustained duration of deviant-elicited responses, seemingly differing in spatio-temporal characteristics from the prediction error responses observed in the superior temporal gyrus, compared with conventional oddball paradigms performed on the same participants. Moreover, we observed that the deviant responses were enhanced through stimulus repetition in the high-gamma range mainly in the superior temporal gyrus. These features of the novel paradigm may aid in our understanding of auditory predictive coding.


Assuntos
Córtex Auditivo , Eletrocorticografia , Humanos , Eletroencefalografia , Potenciais Evocados Auditivos/fisiologia , Córtex Auditivo/fisiologia , Lobo Temporal/fisiologia , Estimulação Acústica , Percepção Auditiva/fisiologia
10.
Cereb Cortex ; 34(2)2024 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-38185997

RESUMO

Semantic knowledge includes understanding of objects and their features and also understanding of the characteristics of events. The hub-and-spoke theory holds that these conceptual representations rely on multiple information sources that are integrated in a central hub in the ventral anterior temporal lobes. The dual-hub theory expands this framework with the claim that the ventral anterior temporal lobe hub is specialized for object representation, while a second hub in angular gyrus is specialized for event representation. To test these ideas, we used representational similarity analysis, univariate and psychophysiological interaction analyses of fMRI data collected while participants processed object and event concepts (e.g. "an apple," "a wedding") presented as images and written words. Representational similarity analysis showed that angular gyrus encoded event concept similarity more than object similarity, although the left angular gyrus also encoded object similarity. Bilateral ventral anterior temporal lobes encoded both object and event concept structure, and left ventral anterior temporal lobe exhibited stronger coding for events. Psychophysiological interaction analysis revealed greater connectivity between left ventral anterior temporal lobe and right pMTG, and between right angular gyrus and bilateral ITG and middle occipital gyrus, for event concepts compared to object concepts. These findings support the specialization of angular gyrus for event semantics, though with some involvement in object coding, but do not support ventral anterior temporal lobe specialization for object concepts.


Assuntos
Mapeamento Encefálico , Lobo Temporal , Humanos , Lobo Temporal/diagnóstico por imagem , Lobo Temporal/fisiologia , Lobo Parietal/fisiologia , Semântica , Imageamento por Ressonância Magnética/métodos
11.
Neurosci Biobehav Rev ; 158: 105535, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38191080

RESUMO

Face-selective regions in the human ventral occipito-temporal cortex (VOTC) have been defined for decades mainly with functional magnetic resonance imaging. This face-selective VOTC network is traditionally divided in a posterior 'core' system thought to subtend face perception, and regions of the anterior temporal lobe as a semantic memory component of an extended general system. In between these two putative systems lies the anterior fusiform gyrus and surrounding sulci, affected by magnetic susceptibility artifacts. Here we suggest that this methodological gap overlaps with and contributes to a conceptual gap between (visual) perception and semantic memory for faces. Filling this gap with intracerebral recordings and direct electrical stimulation reveals robust face-selectivity in the anterior fusiform gyrus and a crucial role of this region, especially in the right hemisphere, in identity recognition for both familiar and unfamiliar faces. Based on these observations, we propose an integrated theoretical framework for human face (identity) recognition according to which face-selective regions in the anterior fusiform gyrus join the dots between posterior and anterior cortical face memories.


Assuntos
Reconhecimento Facial , Prosopagnosia , Humanos , Lobo Temporal/fisiologia , Reconhecimento Facial/fisiologia , Reconhecimento Psicológico , Imageamento por Ressonância Magnética , Reconhecimento Visual de Modelos/fisiologia , Mapeamento Encefálico/métodos , Estimulação Luminosa
12.
Brain Lang ; 249: 105369, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38150793

RESUMO

The perceptual symbol theory proposes a sensorimotor simulation in language processing, emphasizing the role of motor experience. However, the neural basis of motor experience on lexical-level language processing remains little known. In the current fMRI study, we compared brain activation and task-based functional connectivity in 28 rugby players and 28 novices during rugby- specialized and daily verb processing. Distinct differences were observed between the two groups in the bilateral superior temporal gyrus and left angular gyrus regions during specialized verb processing. Notably, intergroup functional connectivity was evident between the left superior temporal gyrus and the right precentral gyrus during specialized verb processing. This study contributes insights into the neural responses and connectivity patterns associated with motor experience at the lexical level, highlighting its potential impact on language processing.


Assuntos
Mapeamento Encefálico , Rugby , Humanos , Idioma , Encéfalo/diagnóstico por imagem , Encéfalo/fisiologia , Lobo Temporal/fisiologia , Imageamento por Ressonância Magnética
13.
Curr Biol ; 34(1): 46-55.e4, 2024 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-38096819

RESUMO

Voices are the most relevant social sounds for humans and therefore have crucial adaptive value in development. Neuroimaging studies in adults have demonstrated the existence of regions in the superior temporal sulcus that respond preferentially to voices. Yet, whether voices represent a functionally specific category in the young infant's mind is largely unknown. We developed a highly sensitive paradigm relying on fast periodic auditory stimulation (FPAS) combined with scalp electroencephalography (EEG) to demonstrate that the infant brain implements a reliable preferential response to voices early in life. Twenty-three 4-month-old infants listened to sequences containing non-vocal sounds from different categories presented at 3.33 Hz, with highly heterogeneous vocal sounds appearing every third stimulus (1.11 Hz). We were able to isolate a voice-selective response over temporal regions, and individual voice-selective responses were found in most infants within only a few minutes of stimulation. This selective response was significantly reduced for the same frequency-scrambled sounds, indicating that voice selectivity is not simply driven by the envelope and the spectral content of the sounds. Such a robust selective response to voices as early as 4 months of age suggests that the infant brain is endowed with the ability to rapidly develop a functional selectivity to this socially relevant category of sounds.


Assuntos
Percepção Auditiva , Voz , Adulto , Lactente , Humanos , Percepção Auditiva/fisiologia , Encéfalo/fisiologia , Lobo Temporal/fisiologia , Estimulação Acústica , Mapeamento Encefálico
14.
J Cogn Neurosci ; 36(1): 24-45, 2024 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-37847811

RESUMO

When preparing to name an object, semantic knowledge about the object and its attributes is activated, including perceptual properties. It is unclear, however, whether semantic attribute activation contributes to lexical access or is a consequence of activating a concept irrespective of whether that concept is to be named or not. In this study, we measured neural responses using fMRI while participants named objects that are typically green or red, presented in black line drawings. Furthermore, participants underwent two other tasks with the same objects, color naming and semantic judgment, to see if the activation pattern we observe during picture naming is (a) similar to that of a task that requires accessing the color attribute and (b) distinct from that of a task that requires accessing the concept but not its name or color. We used representational similarity analysis to detect brain areas that show similar patterns within the same color category, but show different patterns across the two color categories. In all three tasks, activation in the bilateral fusiform gyri ("Human V4") correlated with a representational model encoding the red-green distinction weighted by the importance of color feature for the different objects. This result suggests that when seeing objects whose color attribute is highly diagnostic, color knowledge about the objects is retrieved irrespective of whether the color or the object itself have to be named.


Assuntos
Solanum lycopersicum , Humanos , Encéfalo/diagnóstico por imagem , Lobo Temporal/fisiologia , Mapeamento Encefálico , Semântica , Percepção , Percepção de Cores/fisiologia
15.
Neuroscience ; 538: 59-67, 2024 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-38145822

RESUMO

Prosocial behavior is a common and important aspect of everyday social life. To behave prosocially, we need to learn the consequences of our actions for other people, known as prosocial learning. Previous studies have identified the right temporoparietal junction (rTPJ) as the critical neurological substrate for prosocial behavior. However, little is known about the causal role of the rTPJ in prosocial learning. To clarify the role of the rTPJ in prosocial learning, we used a reinforcement learning paradigm and transcranial direct current stimulation (tDCS). A total of 75 participants were recruited and randomly assigned to the anodal or sham tDCS group. While receiving tDCS stimulation over the rTPJ, participants were instructed to choose between different stimuli that were probabilistically associated with rewards for themselves in the self-learning condition or for another person in the prosocial-learning condition. Participants were able to learn to obtain rewards for themselves or others, and learning performance in the self-learning condition was better than that in the prosocial-learning condition. However, anodal tDCS over the rTPJ significantly improved learning performance in the prosocial-learning condition. These results indicate that the rTPJ plays a causal role in prosocial learning.


Assuntos
Lobo Temporal , Estimulação Transcraniana por Corrente Contínua , Humanos , Lobo Temporal/fisiologia , Lobo Parietal/fisiologia , Estimulação Transcraniana por Corrente Contínua/métodos , Reforço Psicológico , Recompensa
16.
Nat Commun ; 14(1): 8010, 2023 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-38049393

RESUMO

Regions in ventral temporal cortex that are involved in visual recognition of categories like words and faces undergo differential development during childhood. However, categories are also represented in distributed responses across high-level visual cortex. How distributed category representations develop and if this development relates to behavioral changes in recognition remains largely unknown. Here, we used functional magnetic resonance imaging to longitudinally measure the development of distributed responses across ventral temporal cortex to 10 categories in school-age children over several years. Our results reveal both strengthening and weakening of category representations with age, which was mainly driven by changes across category-selective voxels. Representations became particularly more distinct for words in the left hemisphere and for faces bilaterally. Critically, distinctiveness for words and faces across category-selective voxels in left and right lateral ventral temporal cortex, respectively, predicted individual children's word and face recognition performance. These results suggest that the development of distributed representations in ventral temporal cortex has behavioral ramifications and advance our understanding of prolonged cortical development during childhood.


Assuntos
Reconhecimento Facial , Córtex Visual , Criança , Humanos , Reconhecimento Facial/fisiologia , Mapeamento Encefálico/métodos , Lobo Temporal/diagnóstico por imagem , Lobo Temporal/fisiologia , Córtex Visual/diagnóstico por imagem , Córtex Visual/fisiologia , Face , Imageamento por Ressonância Magnética/métodos , Reconhecimento Visual de Modelos/fisiologia , Estimulação Luminosa
17.
Soc Cogn Affect Neurosci ; 18(1)2023 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-38048419

RESUMO

Recognizing facial expressions is dependent on multiple brain networks specialized for different cognitive functions. In the current study, participants (N = 20) were scanned using functional magnetic resonance imaging (fMRI), while they performed a covert facial expression naming task. Immediately prior to scanning thetaburst transcranial magnetic stimulation (TMS) was delivered over the right lateral prefrontal cortex (PFC), or the vertex control site. A group whole-brain analysis revealed that TMS induced opposite effects in the neural responses across different brain networks. Stimulation of the right PFC (compared to stimulation of the vertex) decreased neural activity in the left lateral PFC but increased neural activity in three nodes of the default mode network (DMN): the right superior frontal gyrus, right angular gyrus and the bilateral middle cingulate gyrus. A region of interest analysis showed that TMS delivered over the right PFC reduced neural activity across all functionally localised face areas (including in the PFC) compared to TMS delivered over the vertex. These results suggest that visually recognizing facial expressions is dependent on the dynamic interaction of the face-processing network and the DMN. Our study also demonstrates the utility of combined TMS/fMRI studies for revealing the dynamic interactions between different functional brain networks.


Assuntos
Lobo Temporal , Estimulação Magnética Transcraniana , Humanos , Estimulação Magnética Transcraniana/métodos , Lobo Temporal/fisiologia , Expressão Facial , Rede de Modo Padrão , Mapeamento Encefálico/métodos , Córtex Pré-Frontal/diagnóstico por imagem , Córtex Pré-Frontal/fisiologia , Imageamento por Ressonância Magnética/métodos
18.
Cereb Cortex ; 33(22): 11010-11024, 2023 11 04.
Artigo em Inglês | MEDLINE | ID: mdl-37782936

RESUMO

Social and nonsocial directional stimuli (such as gaze and arrows, respectively) share their ability to trigger attentional processes, although the issue of whether social stimuli generate other additional (and unique) attentional effects is still under debate. In this study, we used the spatial interference paradigm to explore, using functional magnetic resonance imaging, shared and dissociable brain activations produced by gaze and arrows. Results showed a common set of regions (right parieto-temporo-occipital) similarly involved in conflict resolution for gaze and arrows stimuli, which showed stronger co-activation for incongruent than congruent trials. The frontal eye field showed stronger functional connectivity with occipital regions for congruent as compared with incongruent trials, and this effect was enhanced for gaze as compared with arrow stimuli in the right hemisphere. Moreover, spatial interference produced by incongruent (as compared with congruent) arrows was associated with increased functional coupling between the right frontal eye field and a set of regions in the left hemisphere. This result was not observed for incongruent (as compared with congruent) gaze stimuli. The right frontal eye field also showed greater coupling with left temporo-occipital regions for those conditions in which larger conflict was observed (arrow incongruent vs. gaze incongruent trials, and gaze congruent vs. arrow congruent trials). These findings support the view that social and nonsocial stimuli share some attentional mechanisms, while at the same time highlighting other differential effects. Highlights Attentional orienting triggered by social (gaze) and nonsocial (arrow) cues is comparable. When social and nonsocial stimuli are used as targets, qualitatively different behavioral effects are observed. This study explores the neural bases of shared and dissociable neural mechanisms for social and nonsocial stimuli. Shared mechanisms were found in the functional coupling between right parieto-temporo-occipital regions. Dissociable mechanisms were found in the functional coupling between right frontal eye field and ipsilateral and contralateral occipito-temporal regions.


Assuntos
Atenção , Fixação Ocular , Atenção/fisiologia , Lobo Occipital/diagnóstico por imagem , Lobo Occipital/fisiologia , Lobo Temporal/fisiologia , Lobo Frontal/diagnóstico por imagem , Lobo Frontal/fisiologia
19.
Hum Brain Mapp ; 44(17): 5547-5566, 2023 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-37787648

RESUMO

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


Assuntos
Semântica , Lobo Temporal , Humanos , Lobo Temporal/diagnóstico por imagem , Lobo Temporal/fisiologia , Lobo Parietal/fisiologia , Córtex Pré-Frontal/fisiologia , Idioma , Mapeamento Encefálico/métodos , Imageamento por Ressonância Magnética/métodos
20.
Nat Commun ; 14(1): 6336, 2023 10 24.
Artigo em Inglês | MEDLINE | ID: mdl-37875526

RESUMO

Language depends critically on the integration of lexical information across multiple words to derive semantic concepts. Limitations of spatiotemporal resolution have previously rendered it difficult to isolate processes involved in semantic integration. We utilized intracranial recordings in epilepsy patients (n = 58) who read written word definitions. Descriptions were either referential or non-referential to a common object. Semantically referential sentences enabled high frequency broadband gamma activation (70-150 Hz) of the inferior frontal sulcus (IFS), medial parietal cortex, orbitofrontal cortex (OFC) and medial temporal lobe in the left, language-dominant hemisphere. IFS, OFC and posterior middle temporal gyrus activity was modulated by the semantic coherence of non-referential sentences, exposing semantic effects that were independent of task-based referential status. Components of this network, alongside posterior superior temporal sulcus, were engaged for referential sentences that did not clearly reduce the lexical search space by the final word. These results indicate the existence of complementary cortical mosaics for semantic integration in posterior temporal and inferior frontal cortex.


Assuntos
Mapeamento Encefálico , Semântica , Humanos , Mapeamento Encefálico/métodos , Encéfalo/fisiologia , Idioma , Lobo Temporal/fisiologia , Imageamento por Ressonância Magnética/métodos
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