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 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 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.

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.

The interplay between control processes and feature relevance: Evidence from dual-task methodology

2019 ◽  
Vol 73 (3) ◽  
pp. 384-395
Author(s):  
Maria Montefinese ◽  
Glyn Hallam ◽  
Hannah Elizabeth Thompson ◽  
Elizabeth Jefferies
Keyword(s):  
Divided Attention ◽  
Dual Task ◽  
Conceptual Knowledge ◽  
Semantic Representation ◽  
Semantic Knowledge ◽  
Semantic Retrieval ◽  
Semantic Cognition ◽  
Control Processes ◽  
And Control ◽  
Healthy Participants

Neuropsychological studies suggest a distinction between (a) semantic knowledge and (b) control processes that shape the retrieval of conceptual information to suit the task or context. These aspects of semantic cognition are specifically impaired in patients with semantic dementia and semantic aphasia, respectively. However, interactions between the structure of knowledge and control processes that are expected during semantic retrieval have not been fully characterised. In particular, domain-general executive resources may not have equal relevance for the capacity to promote weak yet task relevant features (i.e., “controlled retrieval) and to ignore or suppress distracting information (i.e., “selection”). Here, using a feature selection task, we tested the contribution of featural relevance to semantic performance in healthy participants under conditions of divided attention. Healthy participants showed greater dual-task disruption as the relevance value of the distractor feature linearly increased, supporting the emerging view that semantic relevance is one of the organising principles of the structure of semantic representation. Moreover, word frequency, and inter-correlational strength affected overall performance, but they did not show an interaction with dual-task conditions. These results suggest that domain-general control processes, disrupted by divided attention, are more important to the capacity to efficiently avoid distracting information during semantic decision-making than to the promotion of weak target features. The present study therefore provides novel information about the nature of the interaction between structured conceptual knowledge and control processes that support the retrieval of appropriate information and relates these results to a new theoretical framework, termed controlled semantic cognition.

scholarly journals Executive Semantic Processing Is Underpinned by a Large-scale Neural Network: Revealing the Contribution of Left Prefrontal, Posterior Temporal, and Parietal Cortex to Controlled Retrieval and Selection Using TMS

2012 ◽  
Vol 24 (1) ◽  
pp. 133-147 ◽  
Author(s):  
Carin Whitney ◽  
Marie Kirk ◽  
Jamie O'Sullivan ◽  
Matthew A. Lambon Ralph ◽  
Elizabeth Jefferies
Keyword(s):  
Semantic Processing ◽  
Large Scale ◽  
Semantic Representation ◽  
Inferior Frontal Gyrus ◽  
Semantic Knowledge ◽  
Middle Temporal Gyrus ◽  
Neural Basis ◽  
Healthy Human ◽  
Left Posterior ◽  
Domain Dependence

To understand the meanings of words and objects, we need to have knowledge about these items themselves plus executive mechanisms that compute and manipulate semantic information in a task-appropriate way. The neural basis for semantic control remains controversial. Neuroimaging studies have focused on the role of the left inferior frontal gyrus (LIFG), whereas neuropsychological research suggests that damage to a widely distributed network elicits impairments of semantic control. There is also debate about the relationship between semantic and executive control more widely. We used TMS in healthy human volunteers to create “virtual lesions” in structures typically damaged in patients with semantic control deficits: LIFG, left posterior middle temporal gyrus (pMTG), and intraparietal sulcus (IPS). The influence of TMS on tasks varying in semantic and nonsemantic control demands was examined for each region within this hypothesized network to gain insights into (i) their functional specialization (i.e., involvement in semantic representation, controlled retrieval, or selection) and (ii) their domain dependence (i.e., semantic or cognitive control). The results revealed that LIFG and pMTG jointly support both the controlled retrieval and selection of semantic knowledge. IPS specifically participates in semantic selection and responds to manipulations of nonsemantic control demands. These observations are consistent with a large-scale semantic control network, as predicted by lesion data, that draws on semantic-specific (LIFG and pMTG) and domain-independent executive components (IPS).

scholarly journals An individual differences approach to semantic cognition: Divergent effects of age on representation, retrieval and selection

2017 ◽  
Author(s):  
Paul Hoffman
Keyword(s):  
Older People ◽  
Executive Control ◽  
Semantic Information ◽  
Later Life ◽  
Semantic Knowledge ◽  
Semantic Representations ◽  
Semantic Cognition ◽  
Control Processes ◽  
The Relationship ◽  
Representation Of Knowledge

AbstractSemantic cognition refers to the appropriate use of acquired knowledge about the world. This requires representation of knowledge as well as control processes which ensure that currently-relevant aspects of knowledge are retrieved and selected. Although these abilities can be impaired selectively following brain damage, the relationship between them in healthy individuals is unclear. It is also commonly assumed that semantic cognition is preserved in later life, because older people have greater reserves of knowledge. However, this claim overlooks the possibility of decline in semantic control processes. Here, semantic cognition was assessed in 100 young and older adults. Despite having a broader knowledge base, older people showed specific impairments in semantic control, performing more poorly than young people when selecting among competing semantic representations. Conversely, they showed preserved controlled retrieval of less salient information from the semantic store. Breadth of semantic knowledge was positively correlated with controlled retrieval but was unrelated to semantic selection ability, which was instead correlated with non-semantic executive function. These findings indicate that three distinct elements contribute to semantic cognition: semantic representations that accumulate throughout the lifespan, processes for controlled retrieval of less salient semantic information, which appear age-invariant, and mechanisms for selecting task-relevant aspects of semantic knowledge, which decline with age and may relate more closely to domain-general executive control.

scholarly journals The interplay between semantic control processes and feature relevance: Evidence from dual task methodology

2018 ◽  
Author(s):  
Maria Montefinese ◽  
Glyn Hallam ◽  
Hannah Thompson ◽  
Beth Jefferies
Keyword(s):  
Divided Attention ◽  
Dual Task ◽  
Conceptual Knowledge ◽  
Semantic Representation ◽  
Semantic Knowledge ◽  
Semantic Retrieval ◽  
Semantic Cognition ◽  
Control Processes ◽  
And Control ◽  
Healthy Participants

Neuropsychological studies suggest a distinction between (i) semantic knowledge and (ii) control processes that shape the retrieval of conceptual information to suit the task or context. These aspects of semantic cognition are specifically impaired in patients with semantic dementia and semantic aphasia respectively. However, interactions between the structure of knowledge and control processes that are expected during semantic retrieval have not been fully characterised. In particular, domain-general executive resources may not have equal relevance for the capacity to promote weak yet relevant features (i.e., “controlled retrieval), and to ignore or suppress distracting information (i.e., “selection”). Here, using a feature selection task, we tested the contribution of featural relevance to semantic performance in healthy participants under conditions of divided attention. Healthy participants showed greater dual-task disruption as the relevance value of the distracter feature linearly increased, supporting the emerging view that semantic relevance is one of the organizing principles of the structure of semantic representation. Moreover, target relevance, word frequency and inter-correlational strength affected overall performance, but they did not show an interaction with dual-task conditions. These results suggest that domain-general control processes, disrupted by divided attention, are more relevant to the capacity to efficiently avoid distracting information during semantic decision-making than to the promotion of weak target features. The present study therefore provides novel information about the nature of the interaction between structured conceptual knowledge and control processes that support the retrieval of appropriate information, and relates these results to a new theoretical framework, termed controlled semantic cognition.

scholarly journals Neural correlates of lexical-semantic memory: A voxel-based morphometry study in mild AD, aMCI and normal aging

2011 ◽  
Vol 5 (2) ◽  
pp. 69-77
Author(s):  
Marcio L.F. Balthazar ◽  
Clarissa L. Yasuda ◽  
Tátila M. Lopes ◽  
Fabrício R.S. Pereira ◽  
Benito Pereira Damasceno ◽  
...  
Keyword(s):  
Semantic Memory ◽  
Semantic Processing ◽  
Brain Area ◽  
Semantic Networks ◽  
Normal Aging ◽  
Human Cognition ◽  
Semantic Representations ◽  
Voxel Based Morphometry ◽  
Lexical Semantic ◽  
Semantic Errors

Abstract Neuroanatomical correlations of naming and lexical-semantic memory are not yet fully understood. The most influential approaches share the view that semantic representations reflect the manner in which information has been acquired through perception and action, and that each brain area processes different modalities of semantic representations. Despite these anatomical differences in semantic processing, generalization across different features that have similar semantic significance is one of the main characteristics of human cognition. Methods: We evaluated the brain regions related to naming, and to the semantic generalization, of visually presented drawings of objects from the Boston Naming Test (BNT), which comprises different categories, such as animals, vegetables, tools, food, and furniture. In order to create a model of lesion method, a sample of 48 subjects presenting with a continuous decline both in cognitive functions, including naming skills, and in grey matter density (GMD) was compared to normal young adults with normal aging, amnestic mild cognitive impairment (aMCI) and mild Alzheimer's disease (AD). Semantic errors on the BNT, as well as naming performance, were correlated with whole brain GMD as measured by voxel-based morphometry (VBM). Results: The areas most strongly related to naming and to semantic errors were the medial temporal structures, thalami, superior and inferior temporal gyri, especially their anterior parts, as well as prefrontal cortices (inferior and superior frontal gyri). Conclusion: The possible role of each of these areas in the lexical-semantic networks was discussed, along with their contribution to the models of semantic memory organization.

scholarly journals Neural bases of phonological and semantic processing in early childhood

2019 ◽  
Author(s):  
Avantika Mathur ◽  
Douglas Schultz ◽  
Yingying Wang
Keyword(s):  
Early Childhood ◽  
Phonological Processing ◽  
Reading Ability ◽  
Semantic Processing ◽  
Inferior Frontal Gyrus ◽  
Early Period ◽  
Semantic Knowledge ◽  
Typically Developing ◽  
Typically Developing Children ◽  
Neural Bases

AbstractDuring the early period of reading development, children gain phonological (letter-to-sound mapping) and semantic knowledge (storage and retrieval of word meaning). Their reading ability changes rapidly, accompanied by their learning-induced brain plasticity as they learn to read. This study aims to identify the specialization of phonological and semantic processing in early childhood using a combination of univariate and multivariate pattern analysis. Nineteen typically developing children between the age of five to seven performed visual word-level phonological (rhyming) and semantic (related meaning) judgment tasks during functional magnetic resonance imaging (fMRI) scans. Our multivariate analysis showed that young children with good reading ability have already recruited the left hemispheric regions in the brain for phonological processing, including the inferior frontal gyrus (IFG), superior and middle temporal gyrus, and fusiform gyrus. Additionally, our multivariate results suggested that the sub-regions of the left IFG were specialized for different tasks. Our results suggest the left lateralization of fronto-temporal regions for phonological processing and bilateral activations of parietal regions for semantic processing during early childhood. Our findings indicate that the neural bases of reading have already begun to be shaped in early childhood for typically developing children, which can be used as a control baseline for comparison of children at-risk for reading difficulties.

scholarly journals Patterns of Regional Brain Hypometabolism Associated with Knowledge of Semantic Features and Categories in Alzheimer's Disease

2006 ◽  
Vol 18 (12) ◽  
pp. 2138-2151 ◽  
Author(s):  
Roland Zahn ◽  
Peter Garrard ◽  
Jochen Talazko ◽  
Matthias Gondan ◽  
Philine Bubrowski ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Semantic Memory ◽  
Functional Properties ◽  
Functional Property ◽  
Semantic Knowledge ◽  
Brain Areas ◽  
Functional Features ◽  
Property Verification ◽  
Living Objects

The study of semantic memory in patients with Alzheimer's disease (AD) has raised important questions about the representation of conceptual knowledge in the human brain. It is still unknown whether semantic memory impairments are caused by localized damage to specialized regions or by diffuse damage to distributed representations within nonspecialized brain areas. To our knowledge, there have been no direct correlations of neuroimaging of in vivo brain function in AD with performance on tasks differentially addressing visual and functional knowledge of living and nonliving concepts. We used a semantic verification task and resting 18-fluorodeoxyglucose positron emission tomography in a group of mild to moderate AD patients to investigate this issue. The four task conditions required semantic knowledge of (1) visual, (2) functional properties of living objects, and (3) visual or (4) functional properties of nonliving objects. Visual property verification of living objects was significantly correlated with left posterior fusiform gyrus metabolism (Brodmann's area [BA] 37/19). Effects of visual and functional property verification for non-living objects largely overlapped in the left anterior temporal (BA 38/20) and bilateral premotor areas (BA 6), with the visual condition extending more into left lateral precentral areas. There were no associations with functional property verification for living concepts. Our results provide strong support for anatomically separable representations of living and nonliving concepts, as well as visual feature knowledge of living objects, and against distributed accounts of semantic memory that view visual and functional features of living and nonliving objects as distributed across a common set of brain areas.

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