scholarly journals Multiple dimensions underlying the functional organisation of the language network

2021 ◽  
Author(s):  
Victoria J. Hodgson ◽  
Matthew A. Lambon Ralph ◽  
Rebecca L. Jackson

ABSTRACTUnderstanding the different neural networks that support human language is an ongoing challenge for cognitive neuroscience. Which divisions are capable of distinguishing the functional significance of regions across the language network? A key separation between semantic cognition and phonological processing was highlighted in early meta-analyses, yet these seminal works did not formally test this proposition. Moreover, organisation by domain is not the only possibility. Regions may be organised by the type of process performed, as in the separation between representation and control processes proposed within the Controlled Semantic Cognition framework. The importance of these factors was assessed in a series of activation likelihood estimation meta-analyses that investigated which regions of the language network are consistently recruited for semantic and phonological domains, and for representation and control processes. Whilst semantic and phonological processing consistently recruit many overlapping regions, they can be dissociated (by differential involvement of bilateral anterior temporal lobes and superior temporal gyri) only when using both formal analysis methods and sufficient data. Both semantic and phonological regions are further dissociable into control and representation regions, highlighting this as an additional, distinct dimension on which the language network is functionally organised. Furthermore, some of these control regions overlap with multiple-demand network regions critical for control beyond the language domain, suggesting the relative level of domain-specificity is also informative. Multiple, distinct dimensions are critical to understand the role of language regions. Here we present a proposal as to the core principles underpinning the functional organisation of the language network.SIGNIFICANCE STATEMENTTraditional theories of the organisation of the cortical language network separate areas based on the type of information processed, such as distinct regions representing the meaning of words or their sounds. Here, we re-analyse and update a seminal study, to directly compare these networks. This differentiates some language regions, yet a high degree of overlap is found, suggesting this division alone, does not provide a full mapping of the language network. Additional dimensions, reflecting different kinds of information, are demonstrated to underlie the functional organisation of the language network. First, representation and control processes engage distinct regions in each subdomain. Secondly, comparison outside of language highlights the importance of a ‘domain-specificity’ dimension, distinguishing subdomain-specific semantic control and domain-general control regions.

2019 ◽  
Vol 73 (3) ◽  
pp. 384-395
Author(s):  
Maria Montefinese ◽  
Glyn Hallam ◽  
Hannah Elizabeth Thompson ◽  
Elizabeth Jefferies

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.


2018 ◽  
Author(s):  
Maria Montefinese ◽  
Glyn Hallam ◽  
Hannah Thompson ◽  
Beth Jefferies

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.


Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 2146
Author(s):  
Manuel Andrés Vélez-Guerrero ◽  
Mauro Callejas-Cuervo ◽  
Stefano Mazzoleni

Processing and control systems based on artificial intelligence (AI) have progressively improved mobile robotic exoskeletons used in upper-limb motor rehabilitation. This systematic review presents the advances and trends of those technologies. A literature search was performed in Scopus, IEEE Xplore, Web of Science, and PubMed using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) methodology with three main inclusion criteria: (a) motor or neuromotor rehabilitation for upper limbs, (b) mobile robotic exoskeletons, and (c) AI. The period under investigation spanned from 2016 to 2020, resulting in 30 articles that met the criteria. The literature showed the use of artificial neural networks (40%), adaptive algorithms (20%), and other mixed AI techniques (40%). Additionally, it was found that in only 16% of the articles, developments focused on neuromotor rehabilitation. The main trend in the research is the development of wearable robotic exoskeletons (53%) and the fusion of data collected from multiple sensors that enrich the training of intelligent algorithms. There is a latent need to develop more reliable systems through clinical validation and improvement of technical characteristics, such as weight/dimensions of devices, in order to have positive impacts on the rehabilitation process and improve the interactions among patients, teams of health professionals, and technology.


2020 ◽  
Vol 41 (S1) ◽  
pp. s438-s438
Author(s):  
Mark Stibich ◽  
Sarah Simmons ◽  
Deborah Passey

Background: Ultraviolet light (UV) disinfection using low-pressure mercury lamps has been around since the 1940s. The advent of pulsed-xenon UV for hospital use in 2010 has provided a nontoxic and novel technology for hospital disinfection with the first data presented at the 2010 SHEA Decennial. The purpose of this systematic review and meta-analysis is to examine the current body of evidence for pulsed xenon UV disinfection. Methods: The literature search criteria included the following: research conducted in domestic and international settings using pulsed-xenon for surface disinfection, published between 2000 and 2019, and reporting on environmental effectiveness or hospital-acquired reductions (HAIs). We searched PubMed, Google Scholar, and Web of Science. The meta-analysis included 24 studies: 12 HAI outcome studies and 12 environmental effectiveness studies. Meta-analyses were conducted by calculating the percentage reductions for environmental effectiveness, and for the HAI outcome studies, we used a random-effects model to pool the relative risk of HAI. The outcome studies used 272 and 299 months of data for the experimental and control groups, respectively. Results: There was an overall benefit of using pulsed-xenon UV. The overall relative risk of infection decreased compared to the control arm (RR, 0.64; 95% CI, 0.54–0.76). The percentage reductions in environmental studies were as follows: Clostridioides difficile (94.8%), methicillin-resistant Staphylococcus aureus (91.5%), vancomycin-resistant Enterococcus (99.2%), and aerobic bacteria (94.2%). Conclusions: Overall, pulsed-xenon UV was effective for reducing environmental contamination and had the ability to significantly reduce HAIs.Funding: Xenex, Inc., funded this study.Disclosures: Mark Stibich receives a salary from Xenex and is a shareholder of Xenex. Deborah Passey receives a salary from Xenex Disinfection Services.


2015 ◽  
Vol 25 (4) ◽  
pp. 301-308 ◽  
Author(s):  
N. Solomonov ◽  
J. P. Barber

In the past several decades, increasing evidence supports the efficacy of psychotherapies for depression. The vast majority of findings from meta-analyses, randomized clinical trials (RCTs) and naturalistic studies have demonstrated that well-established psychotherapies (behavioural activation, problem-solving therapy, psychodynamic therapy, cognitive-behavioural therapy, interpersonal therapy and emotion-focused therapy) are superior to no-treatment and control conditions, and are in most cases equally effective in treating depression. However, despite this abundant support for psychotherapies, studies have also consistently shown high drop-out rates, high percentages of non-respondent patients who experience treatment failures, and mixed findings regarding the enduring effects of psychotherapy. Thus, there is a need to develop more personalised treatment models tailored to patients’ needs. A new integrative sequential stepwise approach to the treatment of depression is suggested.


Sign in / Sign up

Export Citation Format

Share Document