scholarly journals Moving Beyond Processing and Analysis-Related Variation in Neuroscience

2021 ◽  
Author(s):  
Xinhui Li ◽  
Lei Ai ◽  
Steve Giavasis ◽  
Hecheng Jin ◽  
Eric Feczko ◽  
...  
Keyword(s):  
Functional Mri ◽  
Functional Neuroimaging ◽  
Critical Evaluation ◽  
Marked Variation ◽  
Related Variation ◽  
Analytic Methods ◽  
Exact Data ◽  
Global Signal ◽  
The Impact

AbstractWhen fields lack consensus standards and ground truths for their analytic methods, reproducibility tends to be more of an ideal than a reality. Such has been the case for functional neuroimaging, where there exists a sprawling space of tools from which scientists can construct processing pipelines and draw interpretations. We provide a critical evaluation of the impact of differences observed in results across five independently developed functional MRI minimal preprocessing pipelines. We show that even when handling the same exact data, inter-pipeline agreement was only moderate, with the specific steps that contribute to the lack of agreement varying across pipeline comparisons. Using a densely sampled test-retest dataset, we show that the limitations imposed by inter-pipeline agreement mainly become appreciable when the reliability of the underlying data is high. We highlight the importance of comparison among analytic tools and parameters, as both widely debated (e.g., global signal regression) and commonly overlooked (e.g., MNI template version) decisions were each found to lead to marked variation. We provide recommendations for incorporating tool-based variability in functional neuroimaging analyses and a supporting infrastructure.

scholarly journals Test-retest reliability of the human functional connectome over consecutive days: identifying highly reliable portions and assessing the impact of methodological choices

2020 ◽  
Vol 4 (3) ◽  
pp. 925-945
Author(s):  
Leonardo Tozzi ◽  
Scott L. Fleming ◽  
Zachary D. Taylor ◽  
Cooper D. Raterink ◽  
Leanne M. Williams
Keyword(s):  
Human Brain ◽  
Functional Neuroimaging ◽  
Intraclass Correlation ◽  
Good Reliability ◽  
Retest Reliability ◽  
Methodological Choices ◽  
Functional Connectome ◽  
Global Signal ◽  
Test Retest Reliability ◽  
The Impact

Countless studies have advanced our understanding of the human brain and its organization by using functional magnetic resonance imaging (fMRI) to derive network representations of human brain function. However, we do not know to what extent these “functional connectomes” are reliable over time. In a large public sample of healthy participants ( N = 833) scanned on two consecutive days, we assessed the test-retest reliability of fMRI functional connectivity and the consequences on reliability of three common sources of variation in analysis workflows: atlas choice, global signal regression, and thresholding. By adopting the intraclass correlation coefficient as a metric, we demonstrate that only a small portion of the functional connectome is characterized by good (6–8%) to excellent (0.08–0.14%) reliability. Connectivity between prefrontal, parietal, and temporal areas is especially reliable, but also average connectivity within known networks has good reliability. In general, while unreliable edges are weak, reliable edges are not necessarily strong. Methodologically, reliability of edges varies between atlases, global signal regression decreases reliability for networks and most edges (but increases it for some), and thresholding based on connection strength reduces reliability. Focusing on the reliable portion of the connectome could help quantify brain trait-like features and investigate individual differences using functional neuroimaging.

Functional MRI in Neurosurgery and Neurology

2018 ◽  
pp. 49-63
Author(s):  
S. Kathleen Bandt ◽  
Dennis D. Spencer
Keyword(s):  
Functional Mri ◽  
Neurological Disorders ◽  
Clinical Medicine ◽  
Functional Neuroimaging ◽  
Brain Activity ◽  
Clinical Care ◽  
Rehabilitation Potential ◽  
Magnetic Resonance Imaging Mri ◽  
The Impact ◽  
The Relationship

The relationship between neuroimaging and the care of patients with neurosurgical and neurological disorders has long been a close one. The integration of these fields dates back to neuroimaging’s earliest days in the 20th century. However, no single imaging technique has had the enduring impact on clinical medicine that magnetic resonance imaging (MRI) has. The impact of MRI has resulted not only from an enhanced understanding of structural abnormalities but also the functional implications of those abnormalities. Beyond this, advances in functional neuroimaging have improved our understanding not only of the functional correlates of lesion disorders but also of non-lesion conditions including developmental, degenerative and movement disorders as well as predicting rehabilitation potential following stroke or traumatic brain injury. The advent of functional MRI (fMRI), which capitalizes on the relationship between cerebral blood flow and neuronal activity, combines all of these advantages together with the ability to define regions of brain activity, or function, and has further revolutionized the clinical care of patients with neurosurgical and neurological disorders. Here, we discuss current fMRI techniques as well as their clinical application to the care of patients with neurosurgical and neurological disorders. We also briefly review other functional imaging modalities beyond fMRI.

scholarly journals Professionals’ views on working in the field of domestic violence and abuse during the first wave of COVID-19: a qualitative study in the Netherlands

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Nicole E. van Gelder ◽  
Ditte L. van Haalen ◽  
Kyra Ekker ◽  
Suzanne A. Ligthart ◽  
Sabine Oertelt-Prigione
Keyword(s):  
Domestic Violence ◽  
The Netherlands ◽  
Working Conditions ◽  
Critical Evaluation ◽  
Physical Contact ◽  
Structured Interviews ◽  
Online Tools ◽  
The Impact ◽  
Domestic Violence And Abuse

Abstract Background The COVID-19 pandemic and lockdown evoked great worries among professionals in the field of domestic violence and abuse (DVA) as they expected a rise of the phenomenon. While many countries reported increased DVA, the Netherlands did not. To understand this discrepancy and the overall impact of the lockdown on DVA support services, we interviewed DVA professionals about their experiences with DVA during the rise of COVID-19, the impact of the lockdown on clients and working conditions, and views on eHealth and online tools. Methods Semi-structured interviews were conducted among 16 DVA professionals with various specializations. This data was analyzed using open thematic coding and content analysis. Results Most professionals did not see an increase in DVA reports but they did notice more severe violence. They experienced less opportunities to detect DVA and worried about their clients’ wellbeing and the quality of (online) care. Furthermore, their working conditions rapidly changed, with working from home and online, and they expressed frustration, insecurity and loneliness. Professionals feel eHealth and online tools are not always suitable but they do see them as an opportunity to increase reach and maintain services when physical contact is not possible. Conclusion This study suggests DVA was probably under-detected during the lockdown rather than not having increased. The Dutch system heavily relies on professionals to detect and report DVA, suggesting a need for critical evaluation of the accessibility of professional help. Professionals experienced significant challenges and should themselves be supported psychologically and in their changed work practices to maintain their ability to aid survivors.

scholarly journals Dynamics of language reorganization after left temporo-parietal and frontal stroke

Brain ◽  
2020 ◽  
Vol 143 (3) ◽  
pp. 844-861 ◽  
Author(s):  
Anika Stockert ◽  
Max Wawrzyniak ◽  
Julian Klingbeil ◽  
Katrin Wrede ◽  
Dorothee Kümmerer ◽  
...  
Keyword(s):  
Functional Mri ◽  
Chronic Phase ◽  
Global Network ◽  
Lesion Location ◽  
Post Stroke ◽  
Language Functions ◽  
Language Recovery ◽  
Patient Groups ◽  
The Impact ◽  
General Networks

Abstract The loss and recovery of language functions are still incompletely understood. This longitudinal functional MRI study investigated the neural mechanisms underlying language recovery in patients with post-stroke aphasia putting particular emphasis on the impact of lesion site. To identify patterns of language-related activation, an auditory functional MRI sentence comprehension paradigm was administered to patients with circumscribed lesions of either left frontal (n = 17) or temporo-parietal (n = 17) cortex. Patients were examined repeatedly during the acute (≤1 week, t1), subacute (1–2 weeks, t2) and chronic phase (>6 months, t3) post-stroke; healthy age-matched control subjects (n = 17) were tested once. The separation into two patient groups with circumscribed lesions allowed for a direct comparison of the contributions of distinct lesion-dependent network components to language reorganization between both groups. We hypothesized that activation of left hemisphere spared and perilesional cortex as well as lesion-homologue cortex in the right hemisphere varies between patient groups and across time. In addition, we expected that domain-general networks serving cognitive control independently contribute to language recovery. First, we found a global network disturbance in the acute phase that is characterized by reduced functional MRI language activation including areas distant to the lesion (i.e. diaschisis) and subsequent subacute network reactivation (i.e. resolution of diaschisis). These phenomena were driven by temporo-parietal lesions. Second, we identified a lesion-independent sequential activation pattern with increased activity of perilesional cortex and bilateral domain-general networks in the subacute phase followed by reorganization of left temporal language areas in the chronic phase. Third, we observed involvement of lesion-homologue cortex only in patients with frontal but not temporo-parietal lesions. Fourth, irrespective of lesion location, language reorganization predominantly occurred in pre-existing networks showing comparable activation in healthy controls. Finally, we detected different relationships of performance and activation in language and domain-general networks demonstrating the functional relevance for language recovery. Our findings highlight that the dynamics of language reorganization clearly depend on lesion location and hence open new perspectives for neurobiologically motivated strategies of language rehabilitation, such as individually-tailored targeted application of neuro-stimulation.

Seed-based dual regression: An illustration of the impact of dual regression's inherent filtering of global signal

2021 ◽  
pp. 109410
Author(s):  
Robert E. Kelly, Jr. ◽  
Matthew J. Hoptman ◽  
Soojin Lee ◽  
George S. Alexopoulos ◽  
Faith M. Gunning ◽  
...  
Keyword(s):  
Global Signal ◽  
Dual Regression ◽  
The Impact

Removal of Confounding Effects of Global Signal in Functional MRI Analyses

NeuroImage ◽  
2001 ◽  
Vol 13 (4) ◽  
pp. 751-758 ◽  
Author(s):  
Adrien E. Desjardins ◽  
Kent A. Kiehl ◽  
Peter F. Liddle
Keyword(s):  
Functional Mri ◽  
Global Signal

A review on membrane applications and transport mechanisms in vacuum membrane distillation

2017 ◽  
Vol 34 (1) ◽  
Author(s):  
Rakesh Baghel ◽  
Sushant Upadhyaya ◽  
Kailash Singh ◽  
Satyendra P. Chaurasia ◽  
Akhilendra B. Gupta ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Membrane Separation ◽  
Critical Evaluation ◽  
Experimental Studies ◽  
Membrane Distillation ◽  
Permeate Flux ◽  
Separation Processes ◽  
Vacuum Membrane Distillation ◽  
Polarization Coefficient ◽  
The Impact

AbstractThe main aim of this article is to provide a state-of-the-art review of the experimental studies on vacuum membrane distillation (VMD) process. An introduction to the history of VMD is carried out along with the other membrane distillation configurations. Recent developments in process, characterization of membrane, module design, transport phenomena, and effect of operating parameters on permeate flux are discussed for VMD in detail. Several heat and mass transfer correlations obtained by various researchers for different VMD modules have been discussed. The impact of membrane fouling with its control in VMD is discussed in detail. In this paper, temperature polarization coefficient and concentration polarization coefficient are elaborated in detail. Integration of VMD with other membrane separation processes/industrial processes have been explained to improve the performance of the system and make it more energy efficient. A critical evaluation of the VMD literature is incorporated throughout this review.

Analytic Methods for Bilirubin in Blood Plasma

1961 ◽  
Vol 7 (6) ◽  
pp. 603-625 ◽  
Author(s):  
Derek Watson
Keyword(s):  
Blood Plasma ◽  
Critical Evaluation ◽  
Coupling Reaction ◽  
Spectrophotometric Methods ◽  
Analytic Methods ◽  
Diazo Coupling ◽  
Diazo Coupling Reaction ◽  
In Blood Plasma

Abstract A critical evaluation of existing colorimetric and spectrophotometric methods for the determination of bilirubin in blood plasma is presented. The stoichiometric equivalences of the reagents used in the diazo coupling reaction are re-evaluated. The elimination of turbidity is discussed, as well as methods using diazo-coupling promoters. Recommendations are made concerning the preservation of specimens to prevent oxidation and procedures that give maximal specificity for the type of bilirubin pigment being assayed.

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