scholarly journals U-shape short-range extrinsic connectivity organisation around the human central sulcus

2020 ◽  
Author(s):  
Alexandre Pron ◽  
Christine Deruelle ◽  
Olivier Coulon
Keyword(s):  
Diffusion Mri ◽  
Short Range ◽  
Spatial Organization ◽  
Structural Connectivity ◽  
Phenotypic Traits ◽  
Group Level ◽  
Central Sulcus ◽  
Fibre Bundles ◽  
Functional Scores ◽  
The Individual

AbstractThe central sulcus is probably one of the most studied folds in the human brain, owing to its clear relationship with primary sensory-motor functional areas. However, due to the difficulty of estimating the trajectories of the U-shape fibres from diffusion MRI, the short structural connectivity of this sulcus remains relatively unknown. In this context, we studied the spatial organization of these U-shape fibres along the central sulcus. Based on high quality diffusion MRI data of 100 right-handed subjects and state-of-the-art pre-processing pipeline, we first define a connectivity space that provide a comprehensive and continuous description of the short-range anatomical connectivity around the central sulcus at both the individual and group levels. We then infer the presence of five major U-shape fibre bundles at the group level in both hemispheres by applying unsupervised clustering in the connectivity space. We propose a quantitative investigation of their position and number of streamlines as a function of phenotypic traits such as sex and hemispheres and functional scores such as handedness and manual dexterity. Main findings of this study are twofold: a description of U-shape short-range connectivity along the central sulcus at group level and the evidence of a significant relationship between the position of three hand related U-shape fibre bundles and the handedness score of subjects.

scholarly journals A functional-structural connectivity metric detects ipsilateral connections with distinct functional specialisation in each hemisphere

2020 ◽  
Author(s):  
Oren Civier ◽  
Marion Sourty ◽  
Fernando Calamante
Keyword(s):  
Functional Connectivity ◽  
Functional Mri ◽  
Measurement Errors ◽  
Diffusion Mri ◽  
Right Hemisphere ◽  
Structural Connectivity ◽  
Joint Analysis ◽  
Fibre Bundles ◽  
Human Connectome Project ◽  
The Brain

AbstractWe introduce a connectomics metric that integrates information on structural connectivity (SC) from diffusion MRI tractography and functional connectivity (FC) from resting-state functional MRI, at individual subject level. The metric is based on the ability of SC to broadly predict FC using a simple linear predictive model; for each connection in the brain, the metric quantifies the deviation from that model. For the metric to capture underlying physiological properties, we minimise systematic measurement errors and processing biases in both SC and FC, and address several challenges with the joint analysis. This also includes a data-driven normalisation approach. The combined metric may provide new information by indirectly assessing white matter structural properties that cannot be inferred from diffusion MRI alone, and/or complex interregional neural interactions that cannot be inferred from functional MRI alone. To demonstrate the utility of the metric, we used young adult data from the Human Connectome Project to examine all bilateral pairs of ipsilateral connections, i.e. each left-hemisphere connection in the brain was paired with its right-hemisphere homologue. We detected a minority of bilateral pairs where the metric value is significantly different across hemispheres, which we suggest reflects cases of ipsilateral connections that have distinct functional specialisation in each hemisphere. The pairs with significant effects spanned all cortical lobes, and also included several cortico-subcortical connections. Our findings highlight the potential in a joint analysis of structural and functional measures of connectivity, both for clinical applications and to help in the interpretation of results from standard functional connectivity analysis.Significance StatementBased on the notion that structure predicts function, the scientific community sought to demonstrate that structural information on fibre bundles that connect brain regions is sufficient to estimate the strength of interregional interactions. However, an accurate prediction using MRI has proved elusive. This paper posits that the failure to predict function from structure originates from limitations in measurement or interpretation of either diffusion MRI (to assess fibre bundles), fMRI (to assess functional interactions), or both. We show that these limitations can be nevertheless beneficial, as the extent of divergence between the two modalities may reflect hard-to-measure properties of interregional connections, such as their functional role in the brain. This provides many insights, including into the division of labour between hemispheres.

scholarly journals Impact of long- and short-range fiber depletion on the cognitive deficits of fronto-temporal dementia

2020 ◽  
Author(s):  
Melissa Savard ◽  
Tharick A. Pascoal ◽  
Thijs Dhollander ◽  
Yasser Iturria-Medina ◽  
Paolo Vitali ◽  
...  
Keyword(s):  
Risk Factors ◽  
White Matter ◽  
Diffusion Mri ◽  
Short Range ◽  
Large Scale ◽  
Structural Connectivity ◽  
Executive Dysfunction ◽  
Cognitive Symptoms ◽  
Whole Brain ◽  
Relative Contribution

AbstractFronto-temporal dementia (FTD) is a neurodegenerative disease characterized by focal atrophy of the gray matter (GM), especially in the frontal and temporal regions. Recent studies suggest a framework where white matter (WM) atrophy plays an important role in FTD pathophysiology. However, these studies often overlook the fact that WM tracts bridging different brain regions may have different vulnerabilities to the disease and the relative contribution of GM atrophy to this WM model, resulting in a less comprehensive understanding of the relationship between clinical symptoms and pathology. Here, by leveraging the sensitivity of advanced diffusion MRI modelling and metrics to precise white matter microstructural properties, we aim to clarify the relative contributions of WM fibers and GM atrophy to the cognitive symptoms typically found in FTD. A total of 155 participant from the Frontotemporal Lobar Degeneration Neuroimaging Initiative (FTLDNI) were analysed, including 68 normal elderly controls (CN), 28 behavioral variants (BV), 26 sematic variants (SV) and 30 progressive non fluent aphasia variants (PNFA) of FTD. Diffusion MRI analysis was performed using two complementary techniques: whole brain fixel-based analysis (FBA) and structural connectivity based on probabilistic tractography. Whole brain GM atrophy was assessed using voxel-based morphometry (VBM). Using a common factor analysis to extract a semantic and an executive factor, we aim to test the relative contribution of WM and GM of specific tracts in predicting cognition. We found that semantic symptoms were mainly dependent on short-range WM fiber disruption, while damage to long-range WM fibers was preferentially associated to executive dysfunction with the GM contribution to cognition being predominant for local processing. Our results support the importance of the disruption of specific WM tracts to the core cognitive symptoms associated with FTD. As large-scale WM tracts, which are particularly vulnerable to vascular disease, were highly associated with executive dysfunction, our findings highlight the importance of controlling for risk factors associated with deep white matter disease, such as vascular risk factors, in patients with FTD in order not to potentiate underlying executive dysfunction.

scholarly journals Cultural behaviours can be experimentally induced in wild baboons despite constraints on social information transmission

2021 ◽  
Author(s):  
Alecia Carter ◽  
Guy Cowlishaw
Keyword(s):  
Social Learning ◽  
Information Transmission ◽  
Social Information ◽  
Phenotypic Traits ◽  
Group Level ◽  
Papio Ursinus ◽  
Individual Level ◽  
Diffusion Of Information ◽  
The Social ◽  
The Individual

The formation of culture in animal societies, including humans, relies on the social transmission of information amongst individuals. This spread depends upon the transmission of social information, or social learning, between individuals. However, not all information spreads. To better understand how constraints at the individual-, dyad- and group-level might influence the formation of culture, we experimentally introduced four innovations (novel behaviours) across three troops of wild chacma baboons (Papio ursinus). At the individual-level, different phenotypic traits constrained individuals' use of social information about the innovations. At the dyad-level, we found evidence for social reinforcement and directed social learning affecting who learnt and from whom. Group-level characteristics also limited the diffusion of information, which spread more slowly through social networks that showed less mixing across age classes. Nevertheless, despite these multi-level limitations, the four innovations quickly spread through all the social groups in which they were tested, suggesting that the formation of animal cultures can be surprisingly resilient to constraints on information transmission.

QUALITY OF INDIVIDUAL AND GROUP LEVEL INTERVENTIONS FOR FIRST EPISODE PSYCHOSIS AT THE TERTIARY PSYCHIATRIC HOSPITAL IN UGANDA.

2020 ◽  
Author(s):  
Emmanuel Kiiza Mwesiga ◽  
Noeline Nakasujja ◽  
Lawrence Nankaba ◽  
Juliet Nakku ◽  
Seggane Musisi
Keyword(s):  
Psychiatric Hospital ◽  
Psychotic Disorders ◽  
First Episode Psychosis ◽  
First Episode ◽  
Group Level ◽  
Group Interventions ◽  
Episode Psychosis ◽  
Essential Components ◽  
The Individual

Introduction: Individual and group level interventions have the largest effect on outcomes in patients with the first episode of psychosis. The quality of these individual and group level interventions provided to first-episode psychosis patients in Uganda is unclear.Methods: The study was performed at Butabika National Psychiatric Teaching and referral hospital in Uganda. A retrospective chart review of recently discharged adult in-patients with the first episode of psychosis was first performed to determine the proportion of participants who received the different essential components for individual and group level interventions. From the different proportions, the quality of the services across the individual and group interventions was determined using the first-Episode Psychosis Services Fidelity Scale (FEPS-FS). The FEPS-FS assigns a grade of 1-5 on a Likert scale depending on the proportion of patients received the different components of the intervention. Results: The final sample included 156 first-episode psychosis patients. The median age was 27 years [IOR (24-36)] with 55% of participants of the female gender. 13 essential components across the individual and group interventions were assessed and their quality quantified. All 13 essential components had poor quality with the range of scores on the FEPS-FS of 1-3. Only one essential component assessed (use of single antipsychotics) had moderate quality.Discussion: Among current services at the National psychiatric hospital of Uganda, the essential for individual and group level interventions for psychotic disorders are of low quality. Further studies are required on how the quality of these interventions can be improved.

Reply to Connor and Evers (2020): Critique of the Bias of Crowds Model Simply Restates the Model

2020 ◽  
Author(s):  
Keith Payne ◽  
Heidi A. Vuletich ◽  
Kristjen B. Lundberg
Keyword(s):  
Implicit Bias ◽  
Group Level ◽  
Systemic Racism ◽  
Individual Level ◽  
The Core ◽  
Psychological Science ◽  
Implicit Biases ◽  
The Individual

The Bias of Crowds model (Payne, Vuletich, & Lundberg, 2017) argues that implicit bias varies across individuals and across contexts. It is unreliable and weakly associated with behavior at the individual level. But when aggregated to measure context-level effects, the scores become stable and predictive of group-level outcomes. We concluded that the statistical benefits of aggregation are so powerful that researchers should reconceptualize implicit bias as a feature of contexts, and ask new questions about how implicit biases relate to systemic racism. Connor and Evers (2020) critiqued the model, but their critique simply restates the core claims of the model. They agreed that implicit bias varies across individuals and across contexts; that it is unreliable and weakly associated with behavior at the individual level; and that aggregating scores to measure context-level effects makes them more stable and predictive of group-level outcomes. Connor and Evers concluded that implicit bias should be considered to really be noisily measured individual construct because the effects of aggregation are merely statistical. We respond to their specific arguments and then discuss what it means to really be a feature of persons versus situations, and multilevel measurement and theory in psychological science more broadly.

The Epistemology of Groups

2020 ◽  
Author(s):  
Jennifer Lackey
Keyword(s):  
Group Level ◽  
Social Significance ◽  
Individual Group ◽  
Key Concepts ◽  
Normative Requirements ◽  
Group Members ◽  
The Individual ◽  
Belief Justification ◽  
In Virtue Of ◽  
Trump Administration

Groups are often said to bear responsibility for their actions, many of which have enormous moral, legal, and social significance. The Trump Administration, for instance, is said to be responsible for the U.S.’s inept and deceptive handling of COVID-19 and the harms that American citizens have suffered as a result. But are groups subject to normative assessment simply in virtue of their individual members being so, or are they somehow agents in their own right? Answering this question depends on understanding key concepts in the epistemology of groups, as we cannot hold the Trump Administration responsible without first determining what it believed, knew, and said. Deflationary theorists hold that group phenomena can be understood entirely in terms of individual members and their states. Inflationary theorists maintain that group phenomena are importantly over and above, or otherwise distinct from, individual members and their states. It is argued that neither approach is satisfactory. Groups are more than their members, but not because they have “minds of their own,” as the inflationists hold. Instead, this book shows how group phenomena—like belief, justification, and knowledge—depend on what the individual group members do or are capable of doing while being subject to group-level normative requirements. This framework, it is argued, allows for the correct distribution of responsibility across groups and their individual members.

scholarly journals Examining the Effects of Three Group-Level Metacognitive Scaffoldings on In-Service Teachers’ Knowledge Building

2021 ◽  
pp. 073563312110308
Author(s):  
Fan Ouyang ◽  
Si Chen ◽  
Yuqin Yang ◽  
Yunqing Chen
Keyword(s):  
Small Groups ◽  
Mixed Method ◽  
Peer Interactions ◽  
Knowledge Building ◽  
Group Level ◽  
Question Asking ◽  
Individual Level ◽  
The Individual ◽  
Task Oriented ◽  
Metacognitive Scaffolding

Group-level metacognitive scaffolding is critical for productive knowledge building. However, previous research mainly focuses on the individual-level metacognitive scaffoldings in helping learners improve knowledge building, and little effort has been made to develop group-level metacognitive scaffolding (GMS) for knowledge building. This research designed three group-level metacognitive scaffoldings of general, task-oriented, and idea-oriented scaffoldings to facilitate in-service teachers’ knowledge building in small groups. A mixed method is used to examine the effects of the GMSs on groups’ knowledge building processes, performances, and perceptions. Results indicate a complication of the effects of GMSs on knowledge building. The idea-oriented scaffolding has potential to facilitate question-asking and perspective-proposing inquiry through peer interactions; the general scaffolding does not necessarily lessen teachers’ idea-centered explanation and elaboration on the individual level; the task-oriented scaffolding has the worst effect. Pedagogical and research implications are discussed to foster knowledge building with the support of GMSs.

scholarly journals Comparative physical activity as a global question to assess physical activity among university students

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Katharina Diehl ◽  
Alessia Brassat ◽  
Jennifer Hilger-Kolb
Keyword(s):  
Physical Activity ◽  
University Students ◽  
Online Survey ◽  
Group Level ◽  
Comparative Measurement ◽  
Cross Sectional ◽  
Physically Active ◽  
Comparative Optimism ◽  
Individual Assessment ◽  
The Individual

Abstract Background To assess physical activity (PA), a comparative measurement – evaluating one’s own PA compared to others – may be an appropriate method. In previous studies, the use of comparative measurements led to an effect known as unrealistic comparative optimism (UCO) – people being unrealistically optimistic about their behavior. Our aim was to use this comparative measurement in university students to quantify the prevalence of UCO at the group level and to draw conclusions on its validity. Methods We used data from the Nutrition and Physical Activity in Adolescence Study (NuPhA), a cross-sectional online survey that included only self-reports (n = 689). To assess PA among students, they were asked to rate their PA level compared to that of their same-aged fellow students. In addition, we used the Godin-Shephard leisure-time PA questionnaire and other questions on PA for comparisons. We used bivariate and cluster-based analyses to identify potential UCO. Results We found that UCO at the group level led to an uneven distribution, with a higher proportion of students who rated themselves as being more physically active than average. However, the individual assessment of PA with a single and simple comparative question seemed to be valid. Discussion A global single comparative question seems useful for studies where PA is measured as a covariate in university students.

scholarly journals Isolated individuals and groups show opposite preferences toward humidity

2018 ◽  
Author(s):  
Mariano Calvo Martín ◽  
Stamatios C. Nicolis ◽  
Isaac Planas-Sitjà ◽  
Jean-Christophe de Biseau ◽  
Jean-Louis Deneubourg
Keyword(s):  
Relative Humidity ◽  
Environmental Conditions ◽  
Group Level ◽  
Individual Level ◽  
Negative Effect ◽  
Multi Level ◽  
The Individual ◽  
Shed Light ◽  
Selection Of

AbstractCockroaches, like most social arthropods, are led to choose collectively among different alternative resting places. These decisions are modulated by different factors, such as environmental conditions (temperature, relative humidity) and sociality (groups size, nature of communications). The aim of this study is to establish the interplay between environmental conditions and the modulation of the interactions between individuals within a group leading to an inversion of preferences. We show that the preferences of isolated cockroaches and groups of 16 individuals, on the selection of the relative humidity of a shelter are inversed and shed light on the mechanisms involved. We suggest that the relative humidity has a multi-level influence on cockroaches, manifested as an attractant effect at the individual level and as a negative effect at the group level, modulating the interactions.

scholarly journals The Online Elicitation of Personal Utility Functions (OPUF) tool: a new method for valuing health states

2022 ◽  
Vol 7 ◽  
pp. 14
Author(s):  
Paul Schneider ◽  
Ben van Hout ◽  
Marike Heisen ◽  
John Brazier ◽  
Nancy Devlin
Keyword(s):  
Utility Functions ◽  
Health State ◽  
Group Level ◽  
Health States ◽  
Online Tool ◽  
Value Set ◽  
Individual Level ◽  
Personal Utility ◽  
Value Sets ◽  
The Individual

Introduction Standard valuation methods, such as TTO and DCE are inefficient. They require data from hundreds if not thousands of participants to generate value sets. Here, we present the Online elicitation of Personal Utility Functions (OPUF) tool; a new type of online survey for valuing EQ-5D-5L health states using more efficient, compositional elicitation methods, which even allow estimating value sets on the individual level. The aims of this study are to report on the development of the tool, and to test the feasibility of using it to obtain individual-level value sets for the EQ-5D-5L. Methods We applied an iterative design approach to adapt the PUF method, previously developed by Devlin et al., for use as a standalone online tool. Five rounds of qualitative interviews, and one quantitative pre-pilot were conducted to get feedback on the different tasks. After each round, the tool was refined and re-evaluated. The final version was piloted in a sample of 50 participants from the UK. A demo of the EQ-5D-5L OPUF survey is available at: https://eq5d5l.me Results On average, it took participants about seven minutes to complete the OPUF Tool. Based on the responses, we were able to construct a personal EQ-5D-5L value set for each of the 50 participants. These value sets predicted a participants' choices in a discrete choice experiment with an accuracy of 80%. Overall, the results revealed that health state preferences vary considerably on the individual-level. Nevertheless, we were able to estimate a group-level value set for all 50 participants with reasonable precision. Discussion We successfully piloted the OPUF Tool and showed that it can be used to derive a group-level as well as personal value sets for the EQ-5D-5L. Although the development of the online tool is still in an early stage, there are multiple potential avenues for further research.

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