scholarly journals MEG Node Degree Differences in Patients with Focal Epilepsy vs. Controls—Influence of Experimental Conditions

2021 ◽  
Vol 11 (12) ◽  
pp. 1590
Author(s):  
Stephan Vogel ◽  
Martin Kaltenhäuser ◽  
Cora Kim ◽  
Nadia Müller-Voggel ◽  
Karl Rössler ◽  
...  
Keyword(s):  
Focal Epilepsy ◽  
Neurological Diseases ◽  
Intraclass Correlation ◽  
Node Degree ◽  
Experimental Conditions ◽  
Whole Brain ◽  
Potential Applications ◽  
Therapy Option ◽  
Drug Resistant Epilepsy ◽  
Correlation Statistics

Drug-resistant epilepsy can be most limiting for patients, and surgery represents a viable therapy option. With the growing research on the human connectome and the evidence of epilepsy being a network disorder, connectivity analysis may be able to contribute to our understanding of epilepsy and may be potentially developed into clinical applications. In this magnetoencephalographic study, we determined the whole-brain node degree of connectivity levels in patients and controls. Resting-state activity was measured at five frequency bands in 15 healthy controls and 15 patients with focal epilepsy of different etiologies. The whole-brain all-to-all imaginary part of coherence in source space was then calculated. Node degree was determined and parcellated and was used for further statistical evaluation. In comparison to controls, we found a significantly higher overall node degree in patients with lesional and non-lesional epilepsy. Furthermore, we examined the conditions of high/reduced vigilance and open/closed eyes in controls, to analyze whether patient node degree levels can be achieved. We evaluated intraclass-correlation statistics (ICC) to evaluate the reproducibility. Connectivity and specifically node degree analysis could present new tools for one of the most common neurological diseases, with potential applications in epilepsy diagnostics.

scholarly journals Unusual Structural Features in the Adduct of Dirhodium Tetraacetate with Lysozyme

2021 ◽  
Vol 22 (3) ◽  
pp. 1496
Author(s):  
Domenico Loreto ◽  
Giarita Ferraro ◽  
Antonello Merlino
Keyword(s):  
Anticancer Agents ◽  
Structural Features ◽  
Side Chain ◽  
Side Chains ◽  
Valuable Insight ◽  
Experimental Conditions ◽  
Egg White Lysozyme ◽  
Potential Applications ◽  
Model Protein ◽  
Hen Egg White

The structures of the adducts formed upon reaction of the cytotoxic paddlewheel dirhodium complex [Rh2(μ-O2CCH3)4] with the model protein hen egg white lysozyme (HEWL) under different experimental conditions are reported. Results indicate that [Rh2(μ-O2CCH3)4] extensively reacts with HEWL:it in part breaks down, at variance with what happens in reactions with other proteins. A Rh center coordinates the side chains of Arg14 and His15. Dimeric Rh–Rh units with Rh–Rh distances between 2.3 and 2.5 Å are bound to the side chains of Asp18, Asp101, Asn93, and Lys96, while a dirhodium unit with a Rh–Rh distance of 3.2–3.4 Å binds the C-terminal carboxylate and the side chain of Lys13 at the interface between two symmetry-related molecules. An additional monometallic fragment binds the side chain of Lys33. These data, which are supported by replicated structural determinations, shed light on the reactivity of dirhodium tetracarboxylates with proteins, providing useful information for the design of new Rh-containing biomaterials with an array of potential applications in the field of catalysis or of medicinal chemistry and valuable insight into the mechanism of action of these potential anticancer agents.

The Effect of General Anesthesia On Test-Retest Reliability of Resting-State FMRI Metrics And Optimization of Scan Length

2021 ◽  
Author(s):  
Faezeh Vedaei ◽  
Mahdi Alizadeh ◽  
Victor M Romo ◽  
Feroze B. Mohamed ◽  
Chengyuan Wu
Keyword(s):  
Resting State ◽  
Intraclass Correlation ◽  
Resting State Fmri ◽  
Frequency Fluctuation ◽  
Retest Reliability ◽  
Factors Affecting ◽  
Fractional Frequency ◽  
Drug Resistant Epilepsy ◽  
Test Retest Reliability ◽  
Scan Length

Abstract Resting-state functional magnetic resonance imaging (rs-fMRI) has been known as a powerful tool in neuroscience. However, exploring the test-retest reliability of the metrics derived from rs-fMRI BOLD signal is essential particularly in the studies of patients with neurological development. Two factors affecting reliability of rs-fMRI measurements including the effect of anesthesia and scan length have been estimated in this study. A total of 9 patients with drug-resistant epilepsy (DRE) of requiring interstitial thermal therapy (LITT) were scanned in two states of awake and under anesthesia. At each state, two rs-fMRI sessions were obtained that each one lasted 15 minutes, and the effect of scan length was evaluated. Voxel-wise rs-fMRI metrics including amplitude of low fractional frequency fluctuation (ALFF), amplitude of low fractional frequency fluctuation (fALFF), functional connectivity (FC), and regional homogeneity (ReHo) were measured. Intraclass correlation coefficient (ICC) was calculated to estimate the reliability between two sessions of scanning for both states. Overall, our finding revealed that reliability improves under anesthesia as well as by increasing the scanning length of the scanning sessions. Furthermore, we showed that the optimal scan length to achieve reliable rs-fMRI measurements was 3.1 – 7.5 minutes shorter in an anesthetized, compared to wakeful state.

SYMPOSIUM: BEHAVIOR MODIFICATION BY DRUGS

PEDIATRICS ◽  
1972 ◽  
Vol 49 (5) ◽  
pp. 702-708 ◽  
Author(s):  
C. Keith Conners
Keyword(s):  
Task Force ◽  
Neurological Diseases ◽  
Brain Dysfunction ◽  
Magnesium Pemoline ◽  
Experimental Conditions ◽  
Drug Study ◽  
Stimulant Medications ◽  
Hyperkinetic Child ◽  
Historical Accident

A number of myths have grown up regarding the behavioral effects and use of stimulant medications with children. The first is that there is a type of child uniquely responsive to stimulant compounds, namely, the hyperkinetic child. The second is that the hyperkinetic child is any child who is sufficiently overactive to be considered a menace by adults. The third is that the stimulant medications act primarily to reduce motor activity in a paradoxical "sedative" fashion; and finally, that the drugs do not influence cognitive and perceptual functioning in these children. I believe that these myths are due partly to the historical accident of the manner in which they were first studied, partly to the imprecision in diagnosis and terminology of classification of patients, and partly to the paucity of systematic data on sufficiently large samples under sufficiently varied experimental conditions. I would like to present the results of studies which bear on these issues, and try to draw some general conclusions regarding the present state of knowledge with regard to the use of the various psychostimulants. In this paper I will deal with dextroamphetamine, methylphenidate, and magnesium pemoline. I. METHYLPHENIDATE AND DEXTROAMPHETAMINE The children for this study were referred from schools, pediatricians, and social agencies for either academic or behavioral difficulties, or both. The subjects retained for the drug study comprised about ⅔ of the original referral sample. They were selected to fit the description of the child with "minimal brain dysfunction" as defined by the National Institute of Neurological Diseases and Stroke (NINDS) Task Force I report.

Identification of a specific functional network altered in poststroke cognitive impairment

Neurology ◽  
2018 ◽  
Vol 90 (21) ◽  
pp. e1879-e1888 ◽  
Author(s):  
Clément Bournonville ◽  
Hilde Hénon ◽  
Thibaut Dondaine ◽  
Christine Delmaire ◽  
Stephanie Bombois ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Clustering Coefficient ◽  
Functional Network ◽  
Cognitive Domain ◽  
Cortical Atrophy ◽  
Node Degree ◽  
Resting State Functional Connectivity ◽  
Stroke Patients ◽  
Whole Brain ◽  
Cognitive Domains

ObjectiveTo study the association between poststroke cognitive impairment and defining a specific resting functional marker.MethodsThe resting-state functional connectivity 6 months after an ischemic stroke in 56 patients was investigated. Twenty-nine of the patients who had an impairment of one or several cognitive domains were compared to 27 without any cognitive deficit. We studied the whole-brain connectivity using 2 complementary approaches: graph theory to study the functional network organization and network-based statistics to explore connectivity between brain regions. We assessed the potential cortical atrophy using voxel-based morphometry analysis.ResultsThe overall topological organization of the functional network was not altered in cognitively impaired stroke patients, who had the same mean node degree, average clustering coefficient, and global efficiency as cognitively healthy stroke patients. Network-based statistics analysis showed that poststroke cognitive impairment was associated with dysfunction of a whole-brain network composed of 167 regions and 178 connections, and functional disconnections between superior, middle, and inferior frontal gyri and the superior and inferior temporal gyri. These regions had connections that were specifically and positively correlated with cognitive domain scores. No intergroup differences in overall gray matter thickness and ischemic infarct topography were observed. To assess the effect of prestroke white matter hyperintensities on connectivity, we included the initial Fazekas scale in the regression model for a second network-based analysis. The resulting network was associated with the same key alterations but had fewer connections.ConclusionsThe observed functional network alterations suggest that the appearance of a cognitive impairment following stroke may be associated with a particular functional alteration, shared specifically between cognitive domains.

scholarly journals Association of physical activity and sedentary time with structural brain networks—The Maastricht Study

GeroScience ◽  
2020 ◽  
Author(s):  
Laura W. M. Vergoossen ◽  
J. F. A. Jansen ◽  
J. J. A. de Jong ◽  
C. D. A. Stehouwer ◽  
N. C. Schaper ◽  
...  
Keyword(s):  
Physical Activity ◽  
Basal Ganglia ◽  
Motor Function ◽  
Sedentary Time ◽  
Brain Regions ◽  
Node Degree ◽  
Whole Brain ◽  
Diabetes Status ◽  
Objectively Measured ◽  
Structural Brain

Abstract We assessed whether objectively measured low- and high-intensity physical activity (LPA and HPA) and sedentary time (ST) were associated with white matter connectivity, both throughout the whole brain and in brain regions involved in motor function. In the large population-based Maastricht Study (n = 1715, age 59.6 ± 8.1 (mean ± standard deviation) years, and 48% women), the amounts of LPA, HPA, and ST were objectively measured during 7 days by an activPAL accelerometer. In addition, using 3T structural and diffusion MRI, we calculated whole brain node degree and node degree of the basal ganglia and primary motor cortex. Multivariable linear regression analysis was performed, and we report standardized regression coefficients (stβ) adjusted for age, sex, education level, wake time, diabetes status, BMI, office systolic blood pressure, antihypertensive medication, total-cholesterol-to-HDL-cholesterol ratio, lipid-modifying medication, alcohol use, smoking status, and history of cardiovascular disease. Lower HPA was associated with lower whole brain node degree after full adjustment (stβ [95%CI] = − 0.062 [− 0.101, − 0.013]; p = 0.014), whereas lower LPA (stβ [95%CI] = − 0.013 [− 0.061, 0.034]; p = 0.580) and higher ST (stβ [95%CI] = − 0.030 [− 0.081, 0.021]; p = 0.250) was not. In addition, lower HPA was associated with lower node degree of the basal ganglia after full adjustment (stβ [95%CI] = − 0.070 [− 0.121, − 0.018]; p = 0.009). Objectively measured lower HPA, but not lower LPA and higher ST, was associated with lower whole brain node degree and node degree in specific brain regions highly specialized in motor function. Further research is needed to establish whether more HPA may preserve structural brain connectivity.

scholarly journals Magnetic Nanoparticles as In Vivo Tracers for Alzheimer’s Disease

2020 ◽  
Vol 6 (1) ◽  
pp. 13
Author(s):  
Bhargy Sharma ◽  
Konstantin Pervushin
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Early Diagnosis ◽  
Contrast Agents ◽  
Neurological Diseases ◽  
Pulse Sequences ◽  
Experimental Conditions ◽  
Magnetic Resonance Imaging Mri ◽  
The Brain

Drug formulations and suitable methods for their detection play a very crucial role in the development of therapeutics towards degenerative neurological diseases. For diseases such as Alzheimer’s disease, magnetic resonance imaging (MRI) is a non-invasive clinical technique suitable for early diagnosis. In this review, we will discuss the different experimental conditions which can push MRI as the technique of choice and the gold standard for early diagnosis of Alzheimer’s disease. Here, we describe and compare various techniques for administration of nanoparticles targeted to the brain and suitable formulations of nanoparticles for use as magnetically active therapeutic probes in drug delivery targeting the brain. We explore different physiological pathways involved in the transport of such nanoparticles for successful entry in the brain. In our lab, we have used different formulations of iron oxide nanoparticles (IONPs) and protein nanocages as contrast agents in anatomical MRI of an Alzheimer’s disease (AD) brain. We compare these coatings and their benefits to provide the best contrast in addition to biocompatibility properties to be used as sustainable drug-release systems. In the later sections, the contrast enhancement techniques in MRI studies are discussed. Examples of contrast-enhanced imaging using advanced pulse sequences are discussed with the main focus on important studies in the field of neurological diseases. In addition, T1 contrast agents such as gadolinium chelates are compared with the T2 contrast agents mainly made of superparamagnetic inorganic metal nanoparticles.

The intraclass correlation coefficient applied for evaluation of data correction, labeling methods, and rectal biopsy sampling in DNA microarray experiments

2003 ◽  
Vol 16 (1) ◽  
pp. 99-106 ◽  
Author(s):  
Linette Pellis ◽  
Nicole L. W. Franssen-van Hal ◽  
Jan Burema ◽  
Jaap Keijer
Keyword(s):  
Gene Expression ◽  
Correlation Coefficient ◽  
Intraclass Correlation Coefficient ◽  
Microarray Analysis ◽  
Dna Microarray ◽  
Microarray Data ◽  
Intraclass Correlation ◽  
Experimental Conditions ◽  
Data Correction ◽  
Dna Microarray Analysis

We show that the intraclass correlation coefficient (ICC) can be used as a relatively simple statistical measure to assess methodological and biological variation in DNA microarray analysis. The ICC is a measure that determines the reproducibility of a variable, which can easily be calculated from an ANOVA table. It is based on the assessment of both systematic deviation and random variation, and it facilitates comparison of multiple samples at once. We used the ICC first to optimize our microarray data normalization method and found that the use of median values instead of mean values improves data correction. Then the reproducibility of different labeling methods was evaluated, and labeling by indirect fluorescent dye incorporation appeared to be more reproducible than direct labeling. Finally, we determined optimal biopsy sampling by analyzing overall variation in gene expression. The variation in gene expression of rectal biopsies within persons decreased when two biopsies were taken instead of one, but it did not considerably improve when more than two biopsies were taken from one person, indicating that it is sufficient to use two biopsies per person for DNA microarray analysis under our experimental conditions. To optimize the accuracy of the microarray data, biopsies from at least six different persons should be used per group.

scholarly journals Chronic subthreshold cortical stimulation for adult drug-resistant focal epilepsy: safety, feasibility, and technique

2018 ◽  
Vol 129 (2) ◽  
pp. 533-543 ◽  
Author(s):  
Panagiotis Kerezoudis ◽  
Sanjeet S. Grewal ◽  
Matthew Stead ◽  
Brian Nils Lundstrom ◽  
Jeffrey W. Britton ◽  
...  
Keyword(s):  
Focal Epilepsy ◽  
Cortical Stimulation ◽  
Adult Patients ◽  
Therapeutic Trial ◽  
Drug Resistant ◽  
Surgical Safety ◽  
Institutional Experience ◽  
Eloquent Cortex ◽  
Drug Resistant Epilepsy ◽  
Seizure Foci

OBJECTIVEEpilepsy surgery is effective for lesional epilepsy, but it can be associated with significant morbidity when seizures originate from eloquent cortex that is resected. Here, the objective was to describe chronic subthreshold cortical stimulation and evaluate its early surgical safety profile in adult patients with epilepsy originating from seizure foci in cortex that is not amenable to resection.METHODSAdult patients with focal drug-resistant epilepsy underwent intracranial electroencephalography monitoring for evaluation of resection. Those with seizure foci in eloquent cortex were not candidates for resection and were offered a short therapeutic trial of continuous subthreshold cortical stimulation via intracranial monitoring electrodes. After a successful trial, electrodes were explanted and permanent stimulation hardware was implanted.RESULTSTen patients (6 males) who underwent chronic subthreshold cortical stimulation between 2014 and 2016 were included. Based on radiographic imaging, intracranial pathologies included cortical dysplasia (n = 3), encephalomalacia (n = 3), cortical tubers (n = 1), Rasmussen encephalitis (n = 1), and linear migrational anomaly (n = 1). The duration of intracranial monitoring ranged from 3 to 20 days. All patients experienced an uneventful postoperative course and were discharged home with a median length of stay of 10 days. No postoperative surgical complications developed (median follow-up length 7.7 months). Seizure severity and seizure frequency improved in all patients.CONCLUSIONSThe authors’ institutional experience with this small group shows that chronic subthreshold cortical stimulation can be safely and effectively performed in appropriately selected patients without postoperative complications. Future investigation will provide further insight to recently published results regarding mechanism and efficacy of this novel and promising intervention.

scholarly journals Robotic Assessment of Wrist Proprioception During Kinaesthetic Perturbations: A Neuroergonomic Approach

2021 ◽  
Vol 15 ◽  
Author(s):  
Erika D'Antonio ◽  
Elisa Galofaro ◽  
Jacopo Zenzeri ◽  
Fabrizio Patané ◽  
Jürgen Konczak ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Neurological Diseases ◽  
External Perturbation ◽  
Recovery Process ◽  
Position Sense ◽  
Matching Task ◽  
Experimental Conditions ◽  
Clinical Scales ◽  
Flexion Extension ◽  
Presentation Sequence

Position sense refers to an aspect of proprioception crucial for motor control and learning. The onset of neurological diseases can damage such sensory afference, with consequent motor disorders dramatically reducing the associated recovery process. In regular clinical practice, assessment of proprioceptive deficits is run by means of clinical scales which do not provide quantitative measurements. However, existing robotic solutions usually do not involve multi-joint movements but are mostly applied to a single proximal or distal joint. The present work provides a testing paradigm for assessing proprioception during coordinated multi-joint distal movements and in presence of kinaesthetic perturbations: we evaluated healthy subjects' ability to match proprioceptive targets along two of the three wrist's degrees of freedom, flexion/extension and abduction/adduction. By introducing rotations along the pronation/supination axis not involved in the matching task, we tested two experimental conditions, which differed in terms of the temporal imposition of the external perturbation: in the first one, the disturbance was provided after the presentation of the proprioceptive target, while in the second one, the rotation of the pronation/ supination axis was imposed during the proprioceptive target presentation. We investigated if (i) the amplitude of the perturbation along the pronation/supination would lead to proprioceptive miscalibration; (ii) the encoding of proprioceptive target, would be influenced by the presentation sequence between the target itself and the rotational disturbance. Eighteen participants were tested by means of a haptic neuroergonomic wrist device: our findings provided evidence that the order of disturbance presentation does not alter proprioceptive acuity. Yet, a further effect has been noticed: proprioception is highly anisotropic and dependent on perturbation amplitude. Unexpectedly, the configuration of the forearm highly influences sensory feedbacks, and significantly alters subjects' performance in matching the proprioceptive targets, defining portions of the wrist workspace where kinaesthetic and proprioceptive acuity are more sensitive. This finding may suggest solutions and applications in multiple fields: from general haptics where, knowing how wrist configuration influences proprioception, might suggest new neuroergonomic solutions in device design, to clinical evaluation after neurological damage, where accurately assessing proprioceptive deficits can dramatically complement regular therapy for a better prediction of the recovery path.

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