scholarly journals The impact of ischemic stroke on connectivity gradients

2018 ◽  
Author(s):  
Şeyma Bayrak ◽  
Ahmed A. Khalil ◽  
Kersten Villringer ◽  
Jochen B. Fiebach ◽  
Arno Villringer ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Three Dimensional ◽  
Connectivity Matrix ◽  
Continuous Space ◽  
Functional Deficits ◽  
Stroke Research ◽  
Low Dimensional ◽  
The Impact ◽  
The Relationship ◽  
The Brain

AbstractUnderstanding the relationship between localized anatomical damage, reorganization, and functional deficits is a major challenge in stroke research. Previous work has shown that localized lesions cause widespread functional connectivity alterations in structurally intact areas, thereby affecting a whole network of interconnected regions. Recent advances suggest an alternative to discrete functional networks by describing a connectivity space based on a low-dimensional embedding of the full connectivity matrix. The dimensions of this space, described as connectivity gradients, capture the similarity of areas’ connections along a continuous space. Here, we defined a three-dimensional connectivity space template based on functional connectivity data from healthy controls. By projecting lesion locations into this space, we demonstrate that ischemic strokes resulted in dimension-specific alterations in functional connectivity over the first week after symptoms onset. Specifically, changes in functional connectivity were captured along connectivity Gradients 1 and 3. The degree of change in functional connectivity was determined by the distance from the lesion along these connectivity gradients regardless of the anatomical distance from the lesion. Together, these results provide a novel framework to study reorganization after stroke and suggest that, rather than only impacting on anatomically proximate areas, the indirect effects of ischemic strokes spread along the brain relative to the space defined by its connectivity.

scholarly journals Comparing Functional Connectivity Matrices: A Geometry-Aware Approach applied to Participant Identification

2019 ◽  
Author(s):  
Manasij Venkatesh ◽  
Joseph Jaja ◽  
Luiz pessoa
Keyword(s):  
Functional Connectivity ◽  
Resting State ◽  
Geodesic Distance ◽  
Pearson Correlation ◽  
Identification Accuracy ◽  
Correlation Structure ◽  
Connectivity Matrix ◽  
Low Dimensional ◽  
Brain Measurements ◽  
The Brain

AbstractUnderstanding the correlation structure associated with multiple brain measurements informs about potential “functional groupings” and network organization. The correlation structure can be conveniently captured in a matrix format that summarizes the relationships among a set of brain measurements involving two regions, for example. Such functional connectivity matrix is an important component of many types of investigation focusing on network-level properties of the brain, including clustering brain states, characterizing dynamic functional states, performing participant identification (so-called “fingerprinting”) understanding how tasks reconfigure brain networks, and inter-subject correlation analysis. In these investigations, some notion of proximity or similarity of functional connectivity matrices is employed, such as their Euclidean distance or Pearson correlation (by correlating the matrix entries). Here, we propose the use of a geodesic distance metric that reflects the underlying non-Euclidean geometry of functional correlation matrices. The approach is evaluated in the context of participant identification (fingerprinting): given a participant’s functional connectivity matrix based on resting-state or task data, how effectively can the participant be identified? Using geodesic distance, identification accuracy was over 95% on resting-state data, and exceeded the Pearson correlation approach by 20%. For whole-cortex regions, accuracy improved on a range of tasks by between 2% and as much as 20%. We also investigated identification using pairs of subnetworks (say, dorsal attention plus default mode), and particular combinations improved accuracy over whole-cortex participant identification by over 10%. The geodesic distance also outperformed Pearson correlation when the former employed a fourth of the data as the latter. Finally, we suggest that low-dimensional distance visualizations based on the geodesic approach help uncover the geometry of task functional connectivity in relation to that during resting-state. We propose that the use of the geodesic distance is an effective way to compare the correlation structure of the brain across a broad range of studies.

scholarly journals Multistage Impacts of the Heavy Rain Process on the Travel Speeds of Urban Roads

2021 ◽  
Vol 10 (8) ◽  
pp. 557
Author(s):  
Qiuping Li ◽  
Haowen Luo ◽  
Xuechen Luan
Keyword(s):  
Traffic Management ◽  
Urban Transportation ◽  
Three Dimensional ◽  
Heavy Rain ◽  
The Road ◽  
Road Surfaces ◽  
Speed Change ◽  
The Impact ◽  
The Relationship ◽  
Personal Travel

Heavy rain causes the highest drop in travel speeds compared with light and moderate rain because it can easily induce flooding on road surfaces, which can continue to hinder urban transportation even after the rainfall is over. However, very few studies have specialized in researching the multistage impacts of the heavy rain process on urban roads, and the cumulative effects of heavy rain in road networks are often overlooked. In this study, the heavy rain process is divided into three consecutive stages, i.e., prepeak, peak, and postpeak. The impact of heavy rain on a road is represented by a three-dimensional traffic speed change ratio vector. Then, the k-means clustering method is implemented to reveal the distinct patterns of speed change ratio vectors. Finally, the characteristics of the links in each cluster are analyzed. An empirical study of Shenzhen, China suggests that there are three major impact patterns in links. The differences among links associated with the three impact patterns are related to the road category, travel speeds in no rain days, and the number of transportation facilities. The findings in this research can contribute to a more in-depth understanding of the relationship between the heavy rain process and the travel speeds of urban roads and provide valuable information for traffic management and personal travel in heavy rain weather.

scholarly journals Three-dimensional approach to understanding the relationship between the Plio-Quaternary stress field and tectonic inversion in the Triassic Cuyo Basin, Argentina

2015 ◽  
Vol 7 (1) ◽  
pp. 459-494
Author(s):  
L. Giambiagi ◽  
S. Spagnotto ◽  
S. M. Moreiras ◽  
G. Gómez ◽  
E. Stahlschmidt ◽  
...  
Keyword(s):  
Stress Field ◽  
Three Dimensional ◽  
Sedimentary Basins ◽  
Strike Slip ◽  
Stress Regime ◽  
Basin Inversion ◽  
Structural Style ◽  
Tectonic Inversion ◽  
The Impact ◽  
The Relationship

Abstract. The Cacheuta sub-basin of the Triassic Cuyo Basin is an example of rift basin inversion contemporaneous to the advance of the Andean thrust front, during the Plio-Quaternary. This basin is one of the most important sedimentary basins in a much larger Triassic NNW-trending depositional system along the southwestern margin of the Pangea supercontinent. The amount and structural style of inversion is provided in this paper by three-dimensional insights into the relationship between inversion of rift-related structures and spatial variations in late Cenozoic stress fields. The Plio-Quaternary stress field exhibits important N–S variations in the foreland area of the Southern Central Andes, between 33 and 34° S, with a southward gradually change from pure compression with σ1 and σ2 being horizontal, to a strike-slip type stress field with σ2 being vertical. We present a 3-D approach for studying the tectonic inversion of the sub-basin master fault associated with strike-slip/reverse to strike-slip faulting stress regimes. We suggest that the inversion of Triassic extensional structures, striking NNW to WNW, occurred during the Plio–Pleistocene in those areas with strike-slip/reverse to strike-slip faulting stress regime, while in the reverse faulting stress regime domain, they remain fossilized. Our example demonstrates the impact of the stress regime on the reactivation pattern along the faults.

Prevalence of ADHD in children born by mothers consuming Frankincense during pregnancy

2021 ◽  
Author(s):  
Alimohammad Ranjbar ◽  
Elahe Kamali Ardakani ◽  
Rahele Zareshahi
Keyword(s):  
Data Gathering ◽  
Control Group ◽  
Case Group ◽  
Dsm V ◽  
History Of ◽  
The Difference ◽  
The Impact ◽  
The Relationship ◽  
The Brain ◽  
Positive Effect

Aims: In Iranian culture, due to some narratives from the prophet Mohammad about the use of frankincense during pregnancy for increasing IQ in children, some women consume frankincense during expectancy. This study's goal is to evaluate the relationship between frankincense used during pregnancy and the incidence of ADHD. Methods: In this study, the case group comprised children 4-17 years old referring to Shahid Chamran Pharmacy in Yazd from summer to winter 2018 for receiving Methylphenidate, those with whom a psychologist had identified ADHD based on DSM-V factors.  The control group included children of the same age group but without ADHD. For data gathering, a checklist was used with some questions on smoking, family history of ADHD, presence/absence of a specific disease during pregnancy, frankincense used during pregnancy, and a chemical medication consumed during pregnancy. Results: The main result demonstrated that the children whose mothers used frankincense during pregnancy were 0.67 times less likely to be affected by ADHD than those whose mothers did not use this substance. However, the difference failed to be statistically significant (P>0.05). Conclusion: Some studies report that frankincense can bear a positive effect on the development of the brain and possibly adequate formation of dendrites trees, axons and induce proper communication between them, so the impact of frankincense on the brain may be justified by its protective effect against the hyperactive child.

scholarly journals Homelessness, Empowerment and Self-reliance in Scotland and Ireland: The Impact of Legal Rights to Housing for Homeless People

2014 ◽  
Vol 43 (4) ◽  
pp. 793-810 ◽  
Author(s):  
BETH WATTS
Keyword(s):  
Service Providers ◽  
Three Dimensional ◽  
Homeless People ◽  
Legal Rights ◽  
Qualitative Comparison ◽  
Social Partnership ◽  
Partnership Model ◽  
Self Reliance ◽  
The Impact ◽  
The Relationship

AbstractThis paper explores the impact of legal rights to housing for homeless people, focusing on the capacity of such rights to ‘empower’ those experiencing homelessness. Lukes’ (2005) three-dimensional view of power, complemented by Bourdieu's (1972) concept of ‘habitus’, is used to distinguish between conceptualisations of empowerment. A distinction is drawn between ‘traditional’ understandings of empowerment, which focus on people's capacity to realise their ‘subjective interests’, and on understandings that foreground ‘real interests’. These latter ‘radical’ perspectives direct attention to people's ‘habitus’ – their internalised dispositions to perceive situations and act in particular ways. Empirically, the paper draws on a qualitative comparison of approaches to homelessness in Scotland and Ireland. Whereas in Scotland virtually all those who are homeless now have a legal right to settled accommodation, Ireland has rejected such a ‘legalistic’ approach, pursuing a consensus driven ‘social partnership’ model. Based on primary research with national experts, service providers and homeless single men in both countries, it is argued that legal rights can effectively empower homeless people. These findings call into question popular and political understandings of the relationship between legal welfare rights and self-reliance.

Insights into the relationship between the haem-binding pocket and the redox potential ofc6cytochromes: four atomic resolution structures ofc6andc6-like proteins fromSynechococcussp. PCC 7002

2014 ◽  
Vol 70 (11) ◽  
pp. 2823-2832 ◽  
Author(s):  
Wojciech Bialek ◽  
Szymon Krzywda ◽  
Pawel Zatwarnicki ◽  
Mariusz Jaskolski ◽  
Piotr Kolesinski ◽  
...  
Keyword(s):  
Redox Potential ◽  
Dipole Moments ◽  
Three Dimensional ◽  
Binding Pocket ◽  
High Similarity ◽  
Surface Charge Distribution ◽  
Function Relationship ◽  
Relationship Of ◽  
The Impact ◽  
The Relationship

The structure of cytochromec6Cfrom the mesophilic cyanobacteriumSynechococcussp. PCC 7002 has been determined at 1.03 Å resolution. This is the first structural report on the recently discovered cyanobacterial cytochromec6-like proteins found in marine and nitrogen-fixing cyanobacteria. Despite high similarity in the overall three-dimensional fold between cytochromesc6andc6C, the latter shows saliently different electrostatic properties in terms of surface charge distribution and dipole moments. Its midpoint redox potential is less than half of the value for typicalc6cytochromes and results mainly from the substitution of one residue in the haem pocket. Here, high-resolution crystal structures of mutants of both cytochromesc6andc6Care presented, and the impact of the mutation of specific residues in the haem-binding pocket on the redox potential is discussed. These findings contribute to the elucidation of the structure–function relationship ofc6-like cytochromes.

scholarly journals Multi-Hops Functional Connectivity Improves Individual Prediction of Fusiform Face Activation via a Graph Neural Network

2021 ◽  
Vol 14 ◽  
Author(s):  
Dongya Wu ◽  
Xin Li ◽  
Jun Feng
Keyword(s):  
Neural Network ◽  
Functional Connectivity ◽  
Brain Connectivity ◽  
Face Area ◽  
The Face ◽  
The Individual ◽  
The Right ◽  
And Function ◽  
The Relationship ◽  
The Brain

Brain connectivity plays an important role in determining the brain region’s function. Previous researchers proposed that the brain region’s function is characterized by that region’s input and output connectivity profiles. Following this proposal, numerous studies have investigated the relationship between connectivity and function. However, this proposal only utilizes direct connectivity profiles and thus is deficient in explaining individual differences in the brain region’s function. To overcome this problem, we proposed that a brain region’s function is characterized by that region’s multi-hops connectivity profile. To test this proposal, we used multi-hops functional connectivity to predict the individual face activation of the right fusiform face area (rFFA) via a multi-layer graph neural network and showed that the prediction performance is essentially improved. Results also indicated that the two-layer graph neural network is the best in characterizing rFFA’s face activation and revealed a hierarchical network for the face processing of rFFA.

scholarly journals Kynurenines increase MRS metabolites in basal ganglia and decrease resting-state connectivity in frontostriatal reward circuitry in depression

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xiangchuan Chen ◽  
Diana J. Beltran ◽  
Valeriya D. Tsygankova ◽  
Bobbi J. Woolwine ◽  
Trusharth Patel ◽  
...  
Keyword(s):  
Basal Ganglia ◽  
Functional Connectivity ◽  
Resting State ◽  
Kynurenine Pathway ◽  
Self Report ◽  
Resonance Spectroscopy ◽  
Neural Function ◽  
Brain Chemistry ◽  
The Impact ◽  
The Brain

AbstractInflammation is associated with the development of anhedonia in major depression (MD), but the pathway by which inflammatory molecules gain access to the brain and lead to anhedonia is not clear. Molecules of the kynurenine pathway (KP), which is activated by inflammation, readily influx into the brain and generate end products that alter brain chemistry, disrupt circuit functioning, and result in the expression of inflammatory behaviors such as anhedonia. We examined the impact of plasma and CSF KP metabolites on brain chemistry and neural function using multimodal neuroimaging in 49 depressed subjects. We measured markers of glial dysfunction and distress including glutamate (Glu) and myo-inositol in the left basal ganglia using magnetic resonance spectroscopy (MRS); metrics of local activity coherence (regional homogeneity, ReHo) and functional connectivity from resting-state functional MRI measures; and anhedonia from the Inventory for Depressive Symptoms-Self Report Version (IDS-SR). Plasma kynurenine/tryptophan (KYN/TRP) ratio and cerebrospinal fluid (CSF) 3-hydroxykynurenine (3HK) were associated with increases in left basal ganglia myo-inositol. Plasma kynurenic acid (KYNA) and KYNA/QA were associated with decreases and quinolinic acid (QA) with increases in left basal ganglia Glu. Plasma and CSF KP were associated with decreases in ReHo in the basal ganglia and dorsomedial prefrontal regions (DMPFC) and impaired functional connectivity between these two regions. DMPFC-basal ganglia mediated the effect of plasma and CSF KP on anhedonia. These findings highlight the pathological impact of KP system dysregulation in mediating inflammatory behaviors such as anhedonia.

Functional connectivity and microstructural changes of the brain in primary Sjögren syndrome: the relationship with depression

2020 ◽  
Vol 61 (12) ◽  
pp. 1684-1694
Author(s):  
Artemis Andrianopoulou ◽  
Anastasia K Zikou ◽  
Loukas G Astrakas ◽  
Nafsika Gerolymatou ◽  
Vasileios Xydis ◽  
...  
Keyword(s):  
White Matter ◽  
Functional Connectivity ◽  
Resting State ◽  
Pulse Sequence ◽  
Sjogren Syndrome ◽  
White Matter Tracts ◽  
Microstructural Changes ◽  
Primary Sjögren Syndrome ◽  
The Relationship ◽  
The Brain

Background Fatigue and depression are among the most common manifestations of primary Sjögren syndrome (pSS), but information is lacking on the relationship with brain function and microstructural changes. Purpose To investigate microstructural changes and brain connectivity in pSS, and to evaluate their relationship with fatigue and depression. Material and Methods The study included 29 patients with pSS (mean age 61.2 ± 12.1 years; disease duration 10.5 ± 5.9 years) and 28 controls (mean age 58.4 ± 9.2 years). All the patients completed the Beck’s depression and Fatigue Assessment Scale questionnaires. The imaging protocol consisted of: (i) standard magnetic resonance imaging (MRI) pulse sequences (FLAIR, 3D T1W); (ii) a diffusion tensor imaging pulse sequence; and (iii) a resting state functional MRI pulse sequence. Resting state brain networks and maps of diffusion metrics were calculated and compared between patients and controls. Results Compared with the controls, the patients with pSS and depression showed increased axial, radial, and mean diffusivity and decreased fractional anisotropy; those without depression showed decreased axial diffusivity in major white matter tracts (superior longitudinal fasciculus, inferior longitudinal fasciculus, corticospinal tract, anterior thalamic radiation, inferior fronto-occipital fasciculus, cingulum, uncinate fasciculus, and forceps minor-major). Decreased brain activation in the sensorimotor network was observed in the patients with pSS compared with the controls. No correlation was found between fatigue and structural or functional changes of the brain. Conclusion pSS is associated with functional connectivity abnormalities of the somatosensory cortex and microstructural abnormalities in major white matter tracts, which are more pronounced in depression.

scholarly journals Long-term consequences of childhood maltreatment: Altered amygdala functional connectivity

2015 ◽  
Vol 27 (4pt2) ◽  
pp. 1577-1589 ◽  
Author(s):  
Kelly Jedd ◽  
Ruskin H. Hunt ◽  
Dante Cicchetti ◽  
Emily Hunt ◽  
Raquel A. Cowell ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Functional Connectivity ◽  
Childhood Maltreatment ◽  
Brain Regions ◽  
Healthy Development ◽  
Early Stress ◽  
History Of ◽  
The Impact ◽  
The Relationship

AbstractChildhood maltreatment is a serious individual, familial, and societal threat that compromises healthy development and is associated with lasting alterations to emotion perception, processing, and regulation (Cicchetti & Curtis, 2005; Pollak, Cicchetti, Hornung, & Reed, 2000; Pollak & Tolley-Schell, 2003). Individuals with a history of maltreatment show altered structural and functional brain development in both frontal and limbic structures (Hart & Rubia, 2012). In particular, previous research has identified hyperactive amygdala responsivity associated with childhood maltreatment (e.g., Dannlowski et al., 2012). However, less is known about the impact of maltreatment on the relationship between the amygdala and other brain regions. The present study employed an emotion processing functional magnetic resonance imaging task to examine task-based activation and functional connectivity in adults who experienced maltreatment as children. The sample included adults with a history of substantiated childhood maltreatment (n = 33) and comparison adults (n = 38) who were well matched on demographic variables, all of whom have been studied prospectively since childhood. The maltreated group exhibited greater activation than comparison participants in the prefrontal cortex and basal ganglia. In addition, maltreated adults showed increased amygdala connectivity with the hippocampus and prefrontal cortex. The results suggest that the intense early stress of childhood maltreatment is associated with lasting alterations to frontolimbic circuitry.

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