scholarly journals Divergent effects of healthy ageing on semantic knowledge and control: Evidence from novel comparisons with semantically-impaired patients

2017 ◽  
Author(s):  
Paul Hoffman
Keyword(s):  
Young People ◽  
Older People ◽  
Low Frequency ◽  
Poor Performance ◽  
Semantic Knowledge ◽  
Semantic Dementia ◽  
Control Processes ◽  
Dementia Patients ◽  
Abstract Words ◽  
And Control

AbstractEffective use of semantic knowledge requires a set of conceptual representations and control processes which ensure that currently-relevant aspects of this knowledge are retrieved and selected. It is well-established that levels of semantic knowledge increase across the lifespan. However, the effects of ageing on semantic control processes have not been assessed. I addressed this issue by comparing the performance profiles of young and older people on a verbal comprehension test. Two sets of variables were used to predict accuracy and RT in each group: (a) the psycholinguistic properties of words probed in each trial, (b) the performance on each trial by two groups of semantically-impaired neuropsychological patients. Young people demonstrated poor performance for low frequency and abstract words, suggesting that they had difficulty processing words with intrinsically weak semantic representations. Indeed, performance in this group was strongly predicted by the performance of patients with semantic dementia, who suffer from degradation of semantic knowledge. In contrast, older adults performed poorly on trials where the target semantic relationship was weak and distractor relationships strong – conditions which require high levels of controlled processing. Their performance was not predicted by the performance of semantic dementia patients, but was predicted by the performance of patients with semantic control deficits. These findings indicate that the effects of ageing on semantic cognition are more complex than has previously been assumed. While older people have larger stores of knowledge than young people, they appear to be less skilled at exercising control over the activation of this knowledge.

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 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 Cocaine Rituals in Club Culture: Intensifying and Controlling Alcohol Intoxication

2021 ◽  
pp. 002204262098651
Author(s):  
Marit Edland-Gryt
Keyword(s):  
Young Adult ◽  
Young People ◽  
Alcohol Intoxication ◽  
Qualitative Interviews ◽  
Cocaine Use ◽  
Interaction Rituals ◽  
Collective Effervescence ◽  
Drinking Culture ◽  
Cocaine Users ◽  
And Control

Clubbing is an important part of the nighttime economy, and cocaine use is, for some young people, an essential part of this clubbing culture. However, the interaction rituals around the use of powder cocaine in this context remain understudied. This study is based on qualitative interviews with young adult recreational cocaine users ( n = 28) and explores how they use cocaine in club settings, in relation to rituals and drinking culture. The analysis identified three main explanations for using cocaine: (a) unity with friends because of shared transgression, (b) the high as a “collective effervescence,” and (c) the possibility to control, extend, and intensify drinking to intoxication. These three explanations illustrate how cocaine rituals were deeply integrated in drinking-to-intoxication rituals, and how the illegality of cocaine use reinforced feelings of unity with friends. In the nighttime economy, cocaine use and its related rituals are used to intensify and control alcohol-fuelled partying.

scholarly journals The Australian labour market in 2020

2021 ◽  
pp. 002218562110022
Author(s):  
Elisa Birch ◽  
Alison Preston
Keyword(s):  
Young People ◽  
Older People ◽  
Labour Market ◽  
Minimum Wage ◽  
Job Loss ◽  
Food Services ◽  
Hours Worked ◽  
The Future

This article provides a review of the Australian labour market in 2020. It outlines the monetary and fiscal responses to COVID-19 (including JobKeeper, JobSeeker and JobMaker policies), describes trends in employment, unemployment and underemployment and summarises the Fair Work Commission’s 2020 minimum wage decision. Data show that in the year to September 2020, total monthly hours worked fell by 5.9% for males and 3.8% for females. Job loss was proportionately larger amongst young people (aged 20–29) and older people. It was also disproportionately higher in female-dominated sectors such as Accommodation and Food Services. Unlike the earlier recession (1991), when more than 90% of jobs lost were previously held by males, a significant share (around 40%) of the job loss in the 2020 recession (year to August 2020) were jobs previously held by females. Notwithstanding a pick-up in employment towards year’s end, the future remains uncertain.

scholarly journals Anhedonia in Semantic Dementia—Exploring Right Hemispheric Contributions to the Loss of Pleasure

2021 ◽  
Vol 11 (8) ◽  
pp. 998
Author(s):  
Siobhán R. Shaw ◽  
Hashim El-Omar ◽  
Siddharth Ramanan ◽  
Olivier Piguet ◽  
Rebekah M. Ahmed ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Temporal Lobe ◽  
Rating Scale ◽  
Right Hemisphere ◽  
Semantic Knowledge ◽  
Semantic Dementia ◽  
Anterior Cingulate ◽  
Functional Impairments ◽  
Lobe Atrophy

Semantic dementia (SD) is a younger-onset neurodegenerative disease characterised by progressive deterioration of the semantic knowledge base in the context of predominantly left-lateralised anterior temporal lobe (ATL) atrophy. Mounting evidence indicates the emergence of florid socioemotional changes in SD as atrophy encroaches into right temporal regions. How lateralisation of temporal lobe pathology impacts the hedonic experience in SD remains largely unknown yet has important implications for understanding socioemotional and functional impairments in this syndrome. Here, we explored how lateralisation of temporal lobe atrophy impacts anhedonia severity on the Snaith–Hamilton Pleasure Scale in 28 SD patients presenting with variable right- (SD-R) and left-predominant (SD-L) profiles of temporal lobe atrophy compared to that of 30 participants with Alzheimer’s disease and 30 healthy older Control participants. Relative to Controls, SD-R but not SD-L or Alzheimer’s patients showed clinically significant anhedonia, representing a clear departure from premorbid levels. Overall, anhedonia was more strongly associated with functional impairment on the Frontotemporal Dementia Functional Rating Scale and motivational changes on the Cambridge Behavioural Inventory in SD than in Alzheimer’s disease patients. Voxel-based morphometry analyses revealed that anhedonia severity correlated with reduced grey matter intensity in a restricted set of regions centred on right orbitofrontal and temporopolar cortices, bilateral posterior temporal cortices, as well as the anterior cingulate gyrus and parahippocampal gyrus, bilaterally. Finally, regression and mediation analysis indicated a unique role for right temporal lobe structures in modulating anhedonia in SD. Our findings suggest that degeneration of predominantly right-hemisphere structures deleteriously impacts the capacity to experience pleasure in SD. These findings offer important insights into hemispheric lateralisation of motivational disturbances in dementia and suggest that anhedonia may emerge at different timescales in the SD disease trajectory depending on the integrity of the right hemisphere.

scholarly journals Association between Metabolic Syndrome Components and Cardiac Autonomic Modulation among Children and Adolescents: A Systematic Review and Meta-Analysis

Biology ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 699
Author(s):  
Rashmi Supriya ◽  
Fei-Fei Li ◽  
Yi-De Yang ◽  
Wei Liang ◽  
Julien S. Baker
Keyword(s):  
Risk Factors ◽  
Young People ◽  
Correlation Coefficient ◽  
High Frequency ◽  
Meta Analysis ◽  
Low Frequency ◽  
Autonomic Modulation ◽  
Cross Sectional ◽  
Cross Sectional Studies ◽  
Positive Correlations

Background: the clustering of metabolic syndrome (MetS) risk factors is becoming more prevalent in children, leading to the development of type 2 diabetes (T2D) and cardiovascular diseases in early adulthood. The impact of MetS risk factors on cardiac autonomic modulation (CAM) or vice versa has been noted to track from childhood to pre-adolescence and adolescence. Understating associations in this age group may help to improve the clinical outcomes of the MetS, even when MetS symptoms are not visible. Potential damage from each individual MetS component and the ability to predict early cardiac damage or upcoming cardiovascular events is very important. Therefore, the present systematic review and meta-analysis investigated the associations between CAM and MetS risk factors individually to verify which of the MetS risk components were significantly correlated with heart rate variability (HRV) indices before or at the onset of the MetS among young people. The purpose of this review was to outline the importance of potentially screening HRV indices in young people even with only one MetS risk factor, as a pre-indicator for early cardiovascular risk stratification. Methods: cross-sectional studies that examined the relationship of MetS risk factors with HRV indices were searched using four databases including PubMed, the Cochrane clinical trials library, Medline and the Web of Science. Correlation coefficients with 95% confidence intervals (95% CI), and random effects meta-analyses of the association between MetS risk factors with HRV indices were performed. Results: out of 14 cross-sectional studies and one case-control study, 8 studies (10 data sets) provided association data for the meta-analysis. Our results indicated significant positive correlations for systolic blood pressure (SBP) (correlation coefficient 0.13 (95%CI: 0.06; 0.19), I2 = 47.26%) and diastolic blood pressure (DBP) (correlation coefficient 0.09 (95%CI: −0.01; 0.18), I2 = 0%) with a Low Frequency/High Frequency ratio (LF/HF). Significant negative correlations for waist circumference (WC) (correlation coefficient −0.12 (95%CI: −0.19; −0.04), I2 = 51.50%), Triglycerides (TGs) (correlation coefficient −0.09 (95%CI: −0.15; −0.02), I2 = 0%) and ≥2 MetS risk factors (correlation coefficient −0.10 (95%CI: −0.16; −0.03), I2 = 0%); with high frequency (HF) were revealed. Significant positive correlations for high density lipoprotein (HDL) (correlation coefficient 0.08 (95%CI: 0.05; 0.11), I2 = 0%) and significant negative correlations of ≥2 MetS risk (correlation coefficient −0.04 (95%CI: −0.12; 0.03), I2 = 0.0%) with low frequency (LF) were revealed. Significant negative correlations for TGs (correlation coefficient −0.09 (95%CI: −0.23; 0.05), I2 = 2.01%) with a mean square root of the sum of differences between mean time between two successive intervals (rMSSD) and significant positive correlation of HDL (correlation coefficient 0.09 (95%CI: −0.01; 0.19), I2 = 0.33%) with standard deviation of the time between two successive intervals (SDNN) were also revealed. An Egger’s test indicated that there was no obvious publication bias for any of the above relationships except for TGs and rMSSD. The significance level stipulated for the meta-analysis was p < 0.05. Conclusions: lipid profiles (HDL and TGs), WC and BP were associated with CAM in young people up to the age of 19 years. The use of HRV indices to predict future MetS risk, and relationships with individual risk factors including HDL, BP, WC and TGs, were established. Future studies related to young people (up to the age of 19 years) are recommended to explore the associations reported here further.

scholarly journals Acoustic source localization using the open spherical microphone array in the low-frequency range

2019 ◽  
Vol 283 ◽  
pp. 04001
Author(s):  
Boquan Yang ◽  
Shengguo Shi ◽  
Desen Yang
Keyword(s):  
Source Localization ◽  
Generalized Inverse ◽  
Microphone Array ◽  
Low Frequency ◽  
Poor Performance ◽  
Microphone Arrays ◽  
Three Dimension ◽  
Frequency Range ◽  
Array Aperture ◽  
Regularization Matrix

Recently, spherical microphone arrays (SMA) have become increasingly significant for source localization and identification in three dimension due to its spherical symmetry. However, conventional Spherical Harmonic Beamforming (SHB) based on SMA has limitations, such as poor resolution and high side-lobe levels in image maps. To overcome these limitations, this paper employs the iterative generalized inverse beamforming algorithm with a virtual extrapolated open spherical microphone array. The sidelobes can be suppressed and the main-lobe can be narrowed by introducing the two iteration processes into the generalized inverse beamforming (GIB) algorithm. The instability caused by uncertainties in actual measurements, such as measurement noise and configuration problems in the process of GIB, can be minimized by iteratively redefining the form of regularization matrix and the corresponding GIB localization results. In addition, the poor performance of microphone arrays in the low-frequency range due to the array aperture can be improved by using a virtual extrapolated open spherical array (EA), which has a larger array aperture. The virtual array is obtained by a kind of data preprocessing method through the regularization matrix algorithm. Both results from simulations and experiments show the feasibility and accuracy of the method.

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