Новые данные о соединениях в инсульте и их роль при выборе лечения

Universitatea de Stat de Medicină şi Farmacie Nicolae TestemiţanuNew research methods of nervous impulse conveyance paths in the human brain, allowed to create a new branch of neuroscience – connectomics, a branch that aims to search for connectivity changes and methods of infl uencing these networks, either for therapeutic goals, or for remodelation. Cerebral vascular accident (stroke) is a localized lesion, usually uni-hemispherical. Still, brain’s remodelation due to this lesion, in order to reestablish normal functionality, implies plastic changes both in neuronal structure, and in cerebral functional connectivity of both hemispheres.Новые методы исследования путей трансмиссии нервного импульса в человеческом мозгу обусловили появление новой ветви в области нейронауки – коннектомика, ветвь, которая изучает изменения соединений и методы влияния этих сетей, как в терапевтических целях, так и в целях перемоделирования. Инсульт является локализованным поражением, как правило однополушарным. И все же перемоделирование мозга, обусловленное этим поражением, для восстановления нормальной функциональности, подразумевает пластические преобразования как в нейрональной структуре, так и в церебральных функциональных соединениях обеих полушарий

Functional and structural connectivity in the motor system in healthy people and in patients with Parkinson’s disease

Parkinson’s disease is the second most frequent chronic neurodegenerative disorder affecting up to 2% of individuals aged 65 years and older. This pathology affects the motor processes determining the patients to have significant difficulties in daily chores. We analysed the influence of transcranial magnetic stimulation on the reaction time in 14 patients with Parkinson’s disease and 13 healthy controls. In a second study we measured the cortical thickness, cortical area and the volumes of thalamus, caudate nucleus, putamen and pallidum of 84 patients and 43 healthy controls. Our results revealed a slower reaction time in patients with Parkinson’s disease when compared to healthy controls. The reaction time was quicker in both groups after applying the magnetic stimulation pulse but patients with Parkinson’s disease still had a slower reaction time compared to healthy controls. Reaction time parameters correlated with a higher cortical thickness in the cingulate motor region and with a lower cortical thickness in the temporal and parietal regions. The second study showed decreased cortical thickness and surface area in Parkinson’s disease patients in the primary motor area, ventral premotor area and the supplementary motor cortex. Decreased cortical area in the motor regions correlated positively with the volumes of the caudate nucleus, putamen and pallidum. The present study shows a different pattern of functional and structural interactions in the motor regions in patients with Parkinson’s disease. Specifically functional and structural connectivity changes due to impaired reaction time were detected in the cingulate motor area, ventral premotor and supplementary motor areas Furthermore, cortical remodelling in PD are associated with changes in the volumes of the caudate nucleus, putamen and pallidum. Both degeneration processes as well as compensatory mechanisms of the brain can explain these changes

Noţiuni de conectivitate şi rezultatele studiilor de conectivitate în epilepsie

Căile din creierul nostru sunt reţele de comunicare și starea lor fi zică infl uenţează efi cienţa comunicaţiei și, respectiv, manifestarea comportamentală. Schimbările din structura substanţei albe, datorită proceselor de plasticitate și adaptare la factorii extrinseci și intrinseci, pot amplifi ca sau pot diminua efi cienţa comunicării, determinând modificări comportamentale. Descărcările epileptice cu certitudine provoacă și, de asemenea, determină schimbările secundare din aceste reţele de comunicare, cu reorganizare funcţională și structurală. Studiile recente atestă schimbări ale conectivităţii structurale în regiunile epileptogenice și ariile interconectate. Reţelele talamocorticale ar putea juca un rol important în cadrul acestei interacţiuni. Articolul dat prezintă o revizuire a studiilor recente de conectivitate în epilepsii. Sunt prezentate problemele de conectivitate structurală și funcţională

Revised Temperament and Character Inventory factors predict neuropsychiatric symptoms and aging-related cognitive decline across 25 years

IntroductionPersonality traits and neuropsychiatric symptoms such as neuroticism and depression share genetic overlap and have both been identified as risks factors for development of aging-related neurocognitive decline and Alzheimer’s disease (AD). This study aimed to examine revised personality factors derived from the Temperament and Character Inventory, previously shown to be associated with psychiatric disorders, as predictors of neuropsychiatric, cognitive, and brain trajectories of participants from a population-based aging study.MethodsMixed-effect linear regression analyses were conducted on data for the full sample (Nmax = 1,286), and a healthy subsample not converting to AD-dementia during 25-year follow-up (Nmax = 1,145), complemented with Cox proportional regression models to determine risk factors for conversion to clinical AD.ResultsTwo personality factors, Closeness to Experience (CE: avoidance of new stimuli, high anxiety, pessimistic anticipation, low reward seeking) and Tendence to Liabilities (TL: inability to change, low autonomy, unaware of the value of their existence) were associated with higher levels of depressive symptoms, stress (CE), sleep disturbance (TL), as well as greater decline in memory, vocabulary and verbal fluency in the full sample. Higher CE was additionally associated with greater memory decline across 25 years in the healthy subsample, and faster right hippocampal volume reduction across 8 years in a neuroimaging subsample (N = 216). Most, but not all, personality-cognition associations persisted after controlling for diabetes, hypertension and cardiovascular disease. Concerning risks for conversion to AD, higher age, and APOE-ε4, but none of the personality measures, were significant predictors.ConclusionThe results indicate that personality traits associated with psychiatric symptoms predict accelerated age-related neurocognitive declines even in the absence of neurodegenerative disease. The attenuation of some personality effects on cognition after adjustment for health indicators suggests that those effects may be partly mediated by somatic health. Taken together, the results further emphasize the importance of personality traits in neurocognitive aging and underscore the need for an integrative (biopsychosocial) perspective of normal and pathological age-related cognitive decline

Evaluación de la presión de fallo del edificio de contención de una central nuclear tipo PWR-W tres lazos. Parte 1: Metodología

Se presenta en este artículo la metodología seguida para la evaluación de la presión de fallo del edificio de contención de una central nuclear PWR-W tres lazos. El análisis debe ser totalmente tridimensional para permitir la consideración de los elementos estructurales más significativos, tener en cuenta el comportamiento no lineal de los materiales y estudiar la sensibilidad de los resultados ante ciertas incertidumbres asociadas a algunos parámetros. El modelo computacional incluye las ecuaciones constitutivas para el hormigón y las armaduras de acero, la discretización espacial (elementos isoparamétricos con armado) y la resolución del problema estructural no lineal mediante algoritmos incrementales-iterativos con aceleradores de convergencia. Se describen los modelos estructurales utilizados y los análisis llevados a cabo para su calibración.Peer Reviewe

Evaluación de la presión de fallo del edificio de contención de una central nuclear tipo PWR-W tres lazos. Parte II: Simulación numérica

En este articulo se presentan los resultados de la simulación numérica efectuada para evaluar la presión de fallo debida a un accidente del edificio de contención de una central nuclear PWR- W tres lazos. El modelo computacional tridimensional de elementos finitos utilizado ha sido descrito en la primera parte del artículo1. En esta segunda parte se analiza la influencia que tiene sobre la presión de fallo de la contención tanto la inclusión en el modelo estructural de la losa de cimentación como los efectos térmicos. El estudio numérico demuestra que puede llevarse a cabo la simulación del proceso de fallo utilizando un modelo estructural que no incluya la losa de cimentación y la carga de temperatura. Finalmente, se presentan y se discuten los resultados de un estudio probabilista de simulación de la presión de fallo y se resumen las conclusiones.Peer Reviewe

Why Is Aging a Risk Factor for Cognitive Impairment in Parkinson's Disease?—A Resting State fMRI Study

Using resting-state functional MRI (rsfMRI) data of younger and older healthy volunteers and patients with Parkinson's disease (PD) with and without mild cognitive impairment (MCI) and applying two different analytic approaches, we investigated the effects of age, pathology, and cognition on brain connectivity. When comparing rsfMRI connectivity strength of PD patients and older healthy volunteers, reduction between multiple brain regions in PD patients with MCI (PD-MCI) compared with PD patients without MCI (PD-non-MCI) was observed. This group difference was not affected by the number and location of clusters but was reduced when age was included as a covariate. Next, we applied a graph-theory method with a cost-threshold approach to the rsfMRI data from patients with PD with and without MCI as well as groups of younger and older healthy volunteers. We observed decreased hub function (measured by degree and betweenness centrality) mainly in the medial prefrontal cortex (mPFC) in older healthy volunteers compared with younger healthy volunteers. We also found increased hub function in the posterior medial structure (precuneus and the cingulate cortex) in PD-non-MCI patients compared with older healthy volunteers and PD-MCI patients. Hub function in these posterior medial structures was positively correlated with cognitive function in all PD patients. Together these data suggest that overlapping patterns of hub modifications could mediate the effect of age as a risk factor for cognitive decline in PD, including age-related reduction of hub function in the mPFC, and recruitment availability of the posterior medial structure, possibly to compensate for impaired basal ganglia function

The Influence of Cold Rolling on the Microstructure for Drawing Steels

The paper presents the structural changes that appeared in steel for deep drawing, as a result of cold rolling and of recrystallization thermal treatment. The research was conducted on samples taken from the rolled strap, treated and rerolled after the present technology in Arcelor Mittal. For comparison samples sampled from the steel strap before cold deforming (hot rolled) were used as blank tests. The thermal processing was done under industrial conditions in bell furnace. For the chosen steel the critical deformation degree was around the value of 6.5%