scholarly journals The role of the angular gyrus in semantic cognition – A synthesis of five functional neuroimaging studies

2021 ◽  
Author(s):  
Philipp Kuhnke ◽  
Curtiss A. Chapman ◽  
Vincent K.M. Cheung ◽  
Sabrina Turker ◽  
Astrid Graessner ◽  
...  
Keyword(s):  
Task Difficulty ◽  
Semantic Processing ◽  
Functional Neuroimaging ◽  
Semantic Knowledge ◽  
Human Cognition ◽  
Angular Gyrus ◽  
Semantic Features ◽  
Semantic Cognition ◽  
Independent Effects

Semantic knowledge is central to human cognition. The angular gyrus (AG) is widely considered a key brain region for semantic cognition. However, the role of the AG in semantic processing is controversial. Key controversies concern response polarity (activation vs. deactivation) and its relation to task difficulty, lateralization (left vs. right AG), and functional-anatomical subdivision (PGa vs. PGp subregions). Here, we combined the fMRI data of five studies on semantic processing (n = 172) and analyzed the response profiles from the same anatomical regions-of-interest for left and right PGa and PGp. We found that the AG was consistently deactivated during non-semantic conditions, whereas response polarity during semantic conditions was inconsistent. However, the AG consistently showed relative response differences between semantic and non-semantic conditions, and between different semantic conditions. A combined analysis across all studies revealed that AG responses could be best explained by independent effects of both task difficulty and semantic processing demand. Task difficulty effects were stronger in PGa than PGp, regardless of hemisphere. Semantic effects were stronger in left than right AG, regardless of subregion. These results suggest that the AG is independently engaged in both domain-general task-difficulty-related processes and domain-specific semantic processes. In semantic processing, we propose that left AG acts as a "multimodal convergence zone" that binds different semantic features associated with the same concept, enabling efficient access to task-relevant features.

scholarly journals The Role of the Angular Gyrus in Semantic Cognition – A Synthesis of Five Functional Neuroimaging Studies

2021 ◽  
Author(s):  
Philipp Kuhnke ◽  
Curtiss A. Chapman ◽  
Vincent K.M. Cheung ◽  
Sabrina Turker ◽  
Astrid Graessner ◽  
...  
Keyword(s):  
Task Difficulty ◽  
Semantic Processing ◽  
Functional Neuroimaging ◽  
Semantic Knowledge ◽  
Human Cognition ◽  
Angular Gyrus ◽  
Semantic Features ◽  
Semantic Cognition ◽  
Independent Effects

Abstract Semantic knowledge is central to human cognition. The angular gyrus (AG) is widely considered a key brain region for semantic cognition. However, the role of the AG in semantic processing is controversial. Key controversies concern response polarity (activation vs. deactivation) and its relation to task difficulty, lateralization (left vs. right AG), and functional-anatomical subdivision (PGa vs. PGp subregions). Here, we combined the fMRI data of five studies on semantic processing (n = 172) and analyzed the response profiles from the same anatomical regions-of-interest for left and right PGa and PGp. We found that the AG was consistently deactivated during non-semantic conditions, whereas response polarity during semantic conditions was inconsistent. However, the AG consistently showed relative response differences between semantic and non-semantic conditions, and between different semantic conditions. A combined analysis across all studies revealed that AG responses could be best explained by independent effects of both task difficulty and semantic processing demand. Task difficulty effects were stronger in PGa than PGp, regardless of hemisphere. Semantic effects were stronger in left than right AG, regardless of subregion. These results suggest that the AG is independently engaged in both domain-general task-difficulty-related processes and domain-specific semantic processes. In semantic processing, we propose that left AG acts as a “multimodal convergence zone” that binds different semantic features associated with the same concept, enabling efficient access to task-relevant features.

Semantic Cognition: Semantic Memory and Semantic Control

2021 ◽  
Author(s):  
Elizabeth Jefferies ◽  
Xiuyi Wang
Keyword(s):  
Semantic Memory ◽  
Semantic Processing ◽  
Inferior Frontal Gyrus ◽  
Semantic Knowledge ◽  
Human Cognition ◽  
Factual Knowledge ◽  
Conceptual Representations ◽  
Semantic Cognition ◽  
Control Processes ◽  
Functional Features

Semantic processing is a defining feature of human cognition, central not only to language, but also to object recognition, the generation of appropriate actions, and the capacity to use knowledge in reasoning, planning, and problem-solving. Semantic memory refers to our repository of conceptual or factual knowledge about the world. This semantic knowledge base is typically viewed as including “general knowledge” as well as schematic representations of objects and events distilled from multiple experiences and retrieved independently from their original spatial or temporal context. Semantic cognition refers to our ability to flexibly use this knowledge to produce appropriate thoughts and behaviors. Semantic cognition includes at least two interactive components: a long-term store of semantic knowledge and semantic control processes, each supported by a different network. Conceptual representations are organized according to the semantic relationships between items, with different theories proposing different key organizational principles, including sensory versus functional features, domain-specific theory, embodied distributed concepts, and hub-and-spoke theory, in which distributed features are integrated within a heteromodal hub in the anterior temporal lobes. The activity within the network for semantic representation must often be controlled to ensure that the system generates representations and inferences that are suited to the immediate task or context. Semantic control is thought to include both controlled retrieval processes, in which knowledge relevant to the goal or context is accessed in a top-down manner when automatic retrieval is insufficient for the task, and post-retrieval selection to resolve competition between simultaneously active representations. Control of semantic retrieval is supported by a strongly left-lateralized brain network, which partially overlaps with the bilateral network that supports domain-general control, but extends beyond these sites to include regions not typically associated with executive control, including anterior inferior frontal gyrus and posterior middle temporal gyrus. The interaction of semantic control processes with conceptual representations allows meaningful thoughts and behavior to emerge, even when the context requires non-dominant features of the concept to be brought to the fore.

scholarly journals The Neural Representations of Movement across Semantic Categories

2019 ◽  
Vol 31 (6) ◽  
pp. 791-807 ◽  
Author(s):  
Valentina Borghesani ◽  
Marianna Riello ◽  
Benno Gesierich ◽  
Valentina Brentari ◽  
Alessia Monti ◽  
...  
Keyword(s):  
Semantic Processing ◽  
Univariate Analysis ◽  
Temporal Cortex ◽  
Representational Content ◽  
Semantic Category ◽  
Semantic Knowledge ◽  
Angular Gyrus ◽  
Semantic Features ◽  
Frontoparietal Network ◽  
Semantic Judgment

Previous evidence from neuropsychological and neuroimaging studies suggests functional specialization for tools and related semantic knowledge in a left frontoparietal network. It is still debated whether these areas are involved in the representation of rudimentary movement-relevant knowledge regardless of semantic domains (animate vs. inanimate) or categories (tools vs. nontool objects). Here, we used fMRI to record brain activity while 13 volunteers performed two semantic judgment tasks on visually presented items from three different categories: animals, tools, and nontool objects. Participants had to judge two distinct semantic features: whether two items typically move in a similar way (e.g., a fan and a windmill move in circular motion) or whether they are usually found in the same environment (e.g., a seesaw and a swing are found in a playground). We investigated differences in overall activation (which areas are involved) as well as representational content (which information is encoded) across semantic features and categories. Results of voxel-wise mass univariate analysis showed that, regardless of semantic category, a dissociation emerges between processing information on prototypical location (involving the anterior temporal cortex and the angular gyrus) and movement (linked to left inferior parietal and frontal activation). Multivoxel pattern correlation analyses confirmed the representational segregation of networks encoding task- and category-related aspects of semantic processing. Taken together, these findings suggest that the left frontoparietal network is recruited to process movement properties of items (including both biological and nonbiological motion) regardless of their semantic category.

Segregating Semantic from Phonological Processes during Reading

1997 ◽  
Vol 9 (6) ◽  
pp. 727-733 ◽  
Author(s):  
C. J. Price ◽  
C. J. Moore ◽  
G. W. Humphreys ◽  
R. J. S. Wise
Keyword(s):  
Semantic Processing ◽  
Functional Neuroimaging ◽  
Temporal Cortex ◽  
Semantic Knowledge ◽  
Task Demands ◽  
Angular Gyrus ◽  
Phonological Processes ◽  
Positron Emission ◽  
Semantic Decision ◽  
Neuropsychological Evidence

A number of previous functional neuroimaging studies have linked activation of the left inferior frontal gyms with semantic processing, yet damage to the frontal lobes does not critically impair semantic knowledge. This study distinguishes between semantic knowledge and the strategic processes required to make verbal decisions. Using positron emission tomography (PET), we identify the neural correlates of semantic knowledge by contrasting semantic decision on visually presented words to phonological decision on the same words. Both tasks involve identical stimuli and a verbal decision on central lingual codes (semantics and phonology), but the explicit task demands directed attention either to meaning or to the segmentation of phonology. Relative to the phonological task, the semantic task was associated with activations in left extrasylvian temporal cortex with the highest activity in the left temporal pole and a posterior region of the left middle temporal cortex (BA 39) close to the angular gyrus. The reverse contrast showed increased activity in both supramarginal gyri, the left precentral sulcus, and the cuneus with a trend toward enhanced activation in the inferior frontal cortex. These results fit well with neuropsychological evidence, associating semantic knowledge with the extrasylvian left temporal cortex and the segmentation of phonology with the perisylvian cortex.

scholarly journals Validated measures of semantic knowledge and semantic control: Normative data from young and older adults for more than 300 semantic judgements

2021 ◽  
Author(s):  
Wei Wu ◽  
Paul Hoffman
Keyword(s):  
Normative Data ◽  
Semantic Processing ◽  
Feature Matching ◽  
Cognitive Architecture ◽  
Later Life ◽  
Semantic Knowledge ◽  
Matching Task ◽  
Large Set ◽  
Semantic Cognition ◽  
Control Processes

Recent studies suggest that knowledge representations and control processes are the two key components underpinning semantic cognition, and are also crucial indicators of the shifting cognitive architecture of semantics in later life. Although there are many standardized assessments that provide measures of the quantity of semantic knowledge participants possess, normative data for tasks that probe semantic control processes are not yet available. Here, we present normative data from more than 200 young and older participants on a large set of stimuli in two semantic tasks, which probe controlled semantic processing (feature-matching task) and semantic knowledge (synonym judgement task). We verify the validity of our norms by replicating established age- and psycholinguistic-property-related effects on semantic cognition. Specifically, we find that older people have more detailed semantic knowledge than young people but have less effective semantic control processes. We also obtain expected effects of word frequency and inter-item competition on performance. Parametrically varied difficulty levels are defined for half of the stimuli based on participants’ behavioral performance, allowing future studies to produce customized sets of experimental stimuli based on our norms. We provide all stimuli, data and code used for analysis, in the hope that they are useful to other researchers.

scholarly journals Syntactic and Semantic Modulation of Neural Activity during Auditory Sentence Comprehension

2006 ◽  
Vol 18 (4) ◽  
pp. 665-679 ◽  
Author(s):  
Colin Humphries ◽  
Jeffrey R. Binder ◽  
David A. Medler ◽  
Einat Liebenthal
Keyword(s):  
Temporal Lobe ◽  
Word Order ◽  
Semantic Processing ◽  
Sentence Comprehension ◽  
Functional Neuroimaging ◽  
Syntactic Structure ◽  
Imaging Study ◽  
Angular Gyrus ◽  
Semantic Structure ◽  
Word Lists

In previous functional neuroimaging studies, left anterior temporal and temporal-parietal areas responded more strongly to sentences than to randomly ordered lists of words. The smaller response for word lists could be explained by either (1) less activation of syntactic processes due to the absence of syntactic structure in the random word lists or (2) less activation of semantic processes resulting from failure to combine the content words into a global meaning. To test these two explanations, we conducted a functional magnetic resonance imaging study in which word order and combinatorial word meaning were independently manipulated during auditory comprehension. Subjects heard six different stimuli: normal sentences, semantically incongruent sentences in which content words were randomly replaced with other content words, pseudoword sentences, and versions of these three sentence types in which word order was randomized to remove syntactic structure. Effects of syntactic structure (greater activation to sentences than to word lists) were observed in the left anterior superior temporal sulcus and left angular gyrus. Semantic effects (greater activation to semantically congruent stimuli than either incongruent or pseudoword stimuli) were seen in widespread, bilateral temporal lobe areas and the angular gyrus. Of the two regions that responded to syntactic structure, the angular gyrus showed a greater response to semantic structure, suggesting that reduced activation for word lists in this area is related to a disruption in semantic processing. The anterior temporal lobe, on the other hand, was relatively insensitive to manipulations of semantic structure, suggesting that syntactic information plays a greater role in driving activation in this area.

scholarly journals Going beyond Inferior Prefrontal Involvement in Semantic Control: Evidence for the Additional Contribution of Dorsal Angular Gyrus and Posterior Middle Temporal Cortex

2013 ◽  
Vol 25 (11) ◽  
pp. 1824-1850 ◽  
Author(s):  
Krist A. Noonan ◽  
Elizabeth Jefferies ◽  
Maya Visser ◽  
Matthew A. Lambon Ralph
Keyword(s):  
Functional Neuroimaging ◽  
Semantic Network ◽  
Temporal Cortex ◽  
Case Series ◽  
Regulatory Control ◽  
Angular Gyrus ◽  
Additional Contribution ◽  
Middle Temporal ◽  
Semantic Cognition ◽  
Semantic Impairment

Semantic cognition requires a combination of semantic representations and executive control processes to direct activation in a task- and time-appropriate fashion [Jefferies, E., & Lambon Ralph, M. A. Semantic impairment in stroke aphasia versus semantic dementia: A case-series comparison. Brain, 129, 2132–2147, 2006]. We undertook a formal meta-analysis to investigate which regions within the large-scale semantic network are specifically associated with the executive component of semantic cognition. Previous studies have described in detail the role of left ventral pFC in semantic regulation. We examined 53 studies that contrasted semantic tasks with high > low executive requirements to determine whether cortical regions beyond the left pFC show the same response profile to executive semantic demands. Our findings revealed that right pFC, posterior middle temporal gyrus (pMTG) and dorsal angular gyrus (bordering intraparietal sulcus) were also consistently recruited by executively demanding semantic tasks, demonstrating patterns of activation that were highly similar to the left ventral pFC. These regions overlap with the lesions in aphasic patients who exhibit multimodal semantic impairment because of impaired regulatory control (semantic aphasia)—providing important convergence between functional neuroimaging and neuropsychological studies of semantic cognition. Activation in dorsal angular gyrus and left ventral pFC was consistent across all types of executive semantic manipulation, regardless of whether the task was receptive or expressive, whereas pMTG activation was only observed for manipulation of control demands within receptive tasks. Second, we contrasted executively demanding tasks tapping semantics and phonology. Our findings revealed substantial overlap between the two sets of contrasts within left ventral pFC, suggesting this region underpins domain-general control mechanisms. In contrast, we observed relative specialization for semantic control within pMTG as well as the most ventral aspects of left pFC (BA 47), consistent with our proposal of a distributed network underpinning semantic control.

scholarly journals Functional MRI Investigation on Paradigmatic and Syntagmatic Lexical Semantic Processing

2020 ◽  
Author(s):  
Songsheng Ying ◽  
Sabine Ploux
Keyword(s):  
Semantic Processing ◽  
Inferior Frontal Gyrus ◽  
Knowledge Bases ◽  
Angular Gyrus ◽  
Semantic Features ◽  
Temporal Pole ◽  
Story Listening ◽  
Contrast Pattern ◽  
Middle Occipital Gyrus ◽  
Ranking Tasks

AbstractThe word embeddings related to paradigmatic and syntagmatic axes are applied in an fMRI encoding experiment to explore human brain’s activity pattern during story listening. This study proposes the construction of paradigmatic and syntagmatic semantic embeddings respectively by transforming WordNet-alike knowledge bases and subtracting paradigmatic information from a statistical word embedding. It evaluates the semantic embeddings by leveraging word-pair proximity ranking tasks and contrasts voxel encoding models trained with the two types of semantic features to reveal the brain’s spatial pattern for semantic processing. Results indicate that in listening comprehension, paradigmatic and syntagmatic semantic operations both recruit inferior (ITG) and middle temporal gyri (MTG), angular gyrus, superior parietal lobule (SPL), inferior frontal gyrus. A non-continuous voxel line is found in MTG with a predominance of paradigmatic processing. The ITG, middle occipital gyrus and the surrounding primary and associative visual areas are more engaged by syntagmatic processing. The comparison of two semantic axes’ brain map does not suggest a neuroanatomical segregation for paradigmatic and syntagmatic processing. The complex yet regular contrast pattern starting from temporal pole, along MTG to SPL necessitates further investigation.

scholarly journals Age-related changes in the neural networks supporting semantic cognition: A meta-analysis of 47 functional neuroimaging studies

2017 ◽  
Author(s):  
Paul Hoffman ◽  
Alexa M. Morcom
Keyword(s):  
Young People ◽  
Semantic Processing ◽  
Functional Neuroimaging ◽  
Semantic Network ◽  
Meta Analysis ◽  
Later Life ◽  
Cognitive Domain ◽  
Neural Basis ◽  
Semantic Cognition ◽  
Age Related

AbstractSemantic cognition is central to understanding of language and the world and, unlike many cognitive domains, is thought to show little age-related decline. We investigated age-related differences in the neural basis of this critical cognitive domain by performing an activation likelihood estimation (ALE) meta-analysis of functional neuroimaging studies comparing young and older people. On average, young people outperformed their older counterparts during semantic tasks. Overall, both age groups activated similar left-lateralised regions. However, older adults displayed less activation than young people in some elements of the typical left-hemisphere semantic network, including inferior prefrontal, posterior temporal and inferior parietal cortex. They also showed greater activation in right frontal and parietal regions, particularly those held to be involved in domain-general controlled processing, and principally when they performed more poorly than the young. Thus, semantic processing in later life is associated with a shift from semantic-specific to domain-general neural resources, consistent with the theory of neural dedifferentiation, and a performance-related reduction in prefrontal lateralisation, which may reflect a response to increased task demands.

scholarly journals The left angular gyrus is causally involved in information buffering and context formation: evidence from a narrative reading task

2019 ◽  
Author(s):  
Francesca M. Branzi ◽  
Gorana Pobric ◽  
JeYoung Jung ◽  
Matthew A. Lambon Ralph
Keyword(s):  
Semantic Processing ◽  
Contextual Information ◽  
Memory Task ◽  
Semantic Integration ◽  
Angular Gyrus ◽  
Reading Task ◽  
Context Dependent ◽  
Human Participants ◽  
Left Angular Gyrus

AbstractThe role of the left angular gyrus (Ag) in semantic processing remains unclear. In this study, we used transcranial magnetic stimulation (TMS) to test the hypothesis that the left Ag supports the information buffering processes necessary for context-dependent semantic integration (narrative reading task). We applied online TMS to the left Ag to disrupt the buffering processes while female and male human participants integrated information between two paragraphs of text presented sequentially (i.e., context and target conditions). We assessed the effect of TMS on the left Ag by recording reading times for target conditions during the reading task and by asking participants to retrieve contextual information given the target condition as cue in a successive memory task. TMS applied over the left Ag during the reading task impaired the retrieval of contextual information in the memory task without affecting reading times. These results suggest that the Ag supports information buffering and context formation. This study provides the first evidence of a causal role of the left Ag in language tasks that require context-dependent semantic integration.Significance statementThe present study offers novel insights into the processes that are associated with the left angular gyrus (Ag) activation during context-dependent naturalistic language processing. We used TMS while human participants read written narratives to interfere with online language integration. We measured how TMS over the left Ag was affecting reading times and retrieval of integrated narrative representations. We were able to show that the left Ag is causally involved in information buffering and context formation.

Sign in / Sign up

Export Citation Format

Share Document