Critical closing pressure as a new hemodynamic marker of cerebral small vessel diseases burden

PurposeTo investigate cerebrovascular hemodynamics, including critical closing pressure (CrCP) and pulsatility index (PI), and their independent relationship with cerebral small vessel disease (CSVD) burden in patients with small-vessel occlusion (SVO).MethodsWe recruited consecutive patients with SVO of acute cerebral infarction who underwent brain magnetic resonance imaging (MRI), transcranial Doppler (TCD) and CrCP during admission. Cerebrovascular hemodynamics were assessed using TCD. We used the CSVD score to rate the total MRI burden of CSVD. Multiple regression analysis was used to determine parameters related to CSVD burden or CrCP.ResultsNinety-seven of 120 patients (mean age, 64.51 ± 9.99 years; 76% male) completed the full evaluations in this study. We observed that CrCP was an independent determinant of CSVD burden in four models [odds ratio, 1.41; 95% confidence interval (CI), 1.17–1.71; P < 0.001] and correlated with CSVD burden [β (95% CI): 0.05 (0.04–0.06); P < 0.001]. In ROC analysis, CrCP was considered as a predictor of CSVD burden, and AUC was 86.2% (95% CI, 78.6–93.9%; P < 0.001). Multiple linear regression analysis showed that CrCP was significantly correlated with age [β (95% CI): 0.27 (0.06 to 0.47); P = 0.012], BMI [β (95% CI): 0.61 (0.00–1.22)] and systolic BP [β (95% CI): 0.16 (0.09–0.23); P < 0.001].ConclusionsCrCP representing cerebrovascular tension is an independent determinant and predictor of CSVD burden. It was significantly correlated with age, BMI and systolic blood pressure. These results provide new insights in the mechanism of CSVD development

What does touch tell us about emotions in touchscreen-based gameplay?

This is the post-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2012 ACM. It is posted here by permission of ACM for your personal use. Not for redistribution.Nowadays, more and more people play games on touch-screen mobile phones. This phenomenon raises a very interesting question: does touch behaviour reflect the player’s emotional state? If possible, this would not only be a valuable evaluation indicator for game designers, but also for real-time personalization of the game experience. Psychology studies on acted touch behaviour show the existence of discriminative affective profiles. In this paper, finger-stroke features during gameplay on an iPod were extracted and their discriminative power analysed. Based on touch-behaviour, machine learning algorithms were used to build systems for automatically discriminating between four emotional states (Excited, Relaxed, Frustrated, Bored), two levels of arousal and two levels of valence. The results were very interesting reaching between 69% and 77% of correct discrimination between the four emotional states. Higher results (~89%) were obtained for discriminating between two levels of arousal and two levels of valence

Behavioral correlates of activity of optogenetically identified locus coeruleus noradrenergic neurons in rats performing T-maze tasks

Abstract The nucleusLocus Coeruleus (LC) is the major source of forebrain norepinephrine. LC is implicated in arousal, response to novelty, and cognitive functions, including decision-making and behavioral flexibility. One hypothesis is that LC activation promotes rapid shifts in cortical attentional networks following changes in environmental contingencies. Recent recordings further suggest LC is critical for mobilizing resources to deal with challenging situations. In the present study optogenetically identified LC neuronal activity was recorded in rats in a self-paced T-maze. Rats were trained on visual discrimination; then place-reward contingencies were instated. In the session where the animal shifted tasks the first time, the LC firing rate after visual cue onset increased significantly, even as the animal adhered to the previous rule. Firing rate also increased prior to crossing photodetectors that controlled stimulus onset and offset, and this was positively correlated with accelerations, consistent with a role in mobilizing effort. The results contribute to the growing evidence that the noradrenergic LC is essential for behavioral adaptation by promoting cognitive flexibility and mobilizing effort in face of changing environmental contingencies

Locus coeruleus noradrenergic neurons phase-lock to prefrontal and hippocampal infra-slow rhythms that synchronize to behavioral events

The locus coeruleus (LC) is the primary source of noradrenergic projections to the forebrain, and, in prefrontal cortex, is implicated in decision-making and executive function. LC neurons phase-lock to cortical infra-slow wave oscillations during sleep. Such infra-slow rhythms are rarely reported in awake states, despite their interest, since they correspond to the time scale of behavior. Thus, we investigated LC neuronal synchrony with infra-slow rhythms in awake rats performing an attentional set-shifting task. Local field potential (LFP) oscillation cycles in prefrontal cortex and hippocampus on the order of 0.4 Hz phase-locked to task events at crucial maze locations. Indeed, successive cycles of the infra-slow rhythms showed different wavelengths, as if they are periodic oscillations that can reset phase relative to salient events. Simultaneously recorded infra-slow rhythms in prefrontal cortex and hippocampus could show different cycle durations as well, suggesting independent control. Most LC neurons (including optogenetically identified noradrenergic neurons) recorded here were phase-locked to these infra-slow rhythms, as were hippocampal and prefrontal units recorded on the LFP probes. The infra-slow oscillations also phase-modulated gamma amplitude, linking these rhythms at the time scale of behavior to those coordinating neuronal synchrony. This would provide a potential mechanism where noradrenaline, released by LC neurons in concert with the infra-slow rhythm, would facilitate synchronization or reset of these brain networks, underlying behavioral adaptation

The direct and mediating effects of cognitive impairment on the occurrence of falls: a cohort study based on community-dwelling old adults

BackgroundCognitive impairment has been reported to be associated with falls in older adults. However, the complex relationship among falls, cognitive impairment and its associated factors, which could be targeted with specific interventions, remains to be elucidated. This study aimed to examine the direct effects of cognitive impairment on falls, to identify the factors associated with cognitive impairment and to explore the mediation role of cognitive impairment in the association of fall with cognition related factors.MethodsThis 1-year follow-up cohort study enrolled old adults aged 60  years or over. Information about demographic and anthropometric characteristics, fall outcomes, function and nutritional status were collected through face-to-face interview. Cognitive function was evaluated by the Montreal Cognitive Assessment (MoCA). Multivariable regression analyses were used to test the association between cognitive impairment and falls and to identify the factors related to cognitive impairment. Additionally, we conduct causal mediation analyses to estimate the mediation effects of cognitive impairment in the pathways of fall occurrence.ResultsOf the 569 participants included in this study, 366 (64.32%) had cognitive impairment, 96 (16.87%) had fall history in the past 1  year, 81 (14.24%) experienced fall and 47 (8.26%) received treatment because of falling during the 1-year follow-up. The association between cognitive impairment and 1-year fall risk was confirmed after adjusting for multiple covariates [odds ratio (OR):2.03, 95% confidence interval (CI): 1.13–3.80]. IADL disability, depression and low grip strength were associated with a higher prevalence of cognitive impairment. While overweight, higher education and higher income level were found to be related to a lower risk of cognitive impairment. Among these associated factors, cognitive impairment mediated the positive association of falling with IADL ability and depression, and a negative relationship with education and income level.ConclusionOur study not only confirmed the direct influence of cognitive impairment on fall risk in older adults, but also suggested a mediating role that cognitive impairment played in the pathways of fall occurrence. Our finding could help develop more specific interventions for fall prevention

Production Scheduling Requirements to Smart Manufacturing

The production scheduling has attracted a lot of researchers for many years, however most of the approaches are not targeted to deal with real manufacturing environments, and those that are, are very particular for the case study. It is crucial to consider important features related with the factories, such as products and machines characteristics and unexpected disturbances, but also information such as when the parts arrive to the factory and when should be delivered. So, the purpose of this paper is to identify some important characteristics that have been considered independently in a lot of studies and that should be considered together to develop a generic scheduling framework to be used in a real manufacturing environment.authorsversionpublishe

Organisation de l'activité neuronale cérébelleuse lors de d'une tâche de préhension et reste dans des rats déplaçant librement

The cerebellum is a brain structure involved in coordination complex motor actions such as voluntary movements. To achieve this function, the precise temporal control of a large population of neurons is required. While a large number of patterned population activity has been characterized in many major brain structures (thalamo-cortical system, basal ganglia, hippocampal formation, etc...), very little is currently known in the cerebellum. Therefore, I investigated the presence and characteristics of such an organization in freely-moving rats, especially when they perform a reach-and-grasp task. The cerebellar cortex has a strong topographical organization, such that neighboring cells share similar input sources and output targets. Therefore, studying the local network properties in the cerebellar cortex allows to access to functionally-relevant population activity. First, I demonstrated that multi-wire electrodes, tetrodes, may be used to record multiple neighboring cells in chronic recordings of freely behaving animals using a custom-made microdrive. Second, I examined in the area of the cerebellar cortex controlling limb movements how the principle cells (the Purkinje cells) coordinate their firing during rest and fast forelimb motor action. Using simultaneous electrophysiological recordings of multiple single cells, I found that neighboring Purkinje cells exhibit consistently a co-modulation of their firing rate at time scale of a few milliseconds. This correlated firing is observed during sleep and active exploration, and increases during motor execution. Our results thus indicate that during a fast and complex movement, local assemblies of Purkinje cells form dynamically at short time scales and will produce very transient episodes of inhibition in the deep cerebellar nuclei. Third, in a collaboration with the group of Richard Courtemanche, we studied the link between neuronal firing and slow local field oscillations that are observed in the cerebellum at rest. We found that a large proportion of Golgi cells and Purkinje cells are modulated during the oscillations. These results indicate that these slow oscillations, that may be also observed in the motor cortex, are propagated in the cerebellar cortex. Overall, my work has identified and characterized a number of state-dependent population activity patterns in the cerebellar cortex. How these patterns impact on the motor system largely remains to be understood and should be examined in future studies.Le cervelet est une structure du cerveau impliquée dans la coordination des actions motrices complexes telles que les mouvements volontaires. Pour remplir cette fonction, le contrôle temporel précis d'une large population de neurones est nécessaire. Alors qu'un grand nombre d'études ont été consacrées à l'étude de l'activité de réseau dans la plupart des grandes structures cérébrales (système thalamo-cortical, les noyaux gris centraux, hippocampe, etc ...), le cervelet reste très peu étudié. Par conséquent, j'ai examiné la présence et les caractéristiques d'une telle organisation chez les rats libres de leurs mouvements, en particulier lorsqu'ils accomplissent une tâche de préhension. Le cortex cérébelleux a une organisation topographique marquée, de sorte que les cellules voisines reçoivent les mêmes afférences et ont des efférences convergentes. Par conséquent, l'étude des propriétés du réseau local dans le cortex cérébelleux permet d'accéder à une activité populationnelle qui est fonctionnellement pertinente. Tout d'abord, j'ai démontré que les multi-électrodes et particulièrement les tétrodes peuvent être utilisées, grâce à un " micro-drive " que j'ai conçu et réalisé, pour enregistrer plusieurs cellules voisines dans des enregistrements chroniques de comportement de rongeurs libres de leurs mouvements.Deuxièmement, j'ai examiné dans la zone du cortex cérébelleux qui contrôle les mouvements des membres la façon dont les cellules principales (les cellules de Purkinje) coordonnent leur décharge pendant le repos et durant une action motrice des membres antérieurs. Par des enregistrements électrophysiologiques simultanés de plusieurs cellules individuelles, j'ai trouvé que les cellules de Purkinje voisines présentent toujours un co-modulation de leur taux de décharge à l'échelle de quelques millisecondes. Cette décharge corrélée est observée pendant le sommeil et d'exploration active, mais elle est accrue au cours de l'exécution de mouvements. Nos résultats indiquent donc que lors d'un mouvement rapide et complexe, les assemblées locales des cellules de Purkinje se forment dynamiquement à des échelles de temps courtes et produisent donc des épisodes très transitoires d'inhibition dans leur cible postsynaptique dans les noyaux cérébelleux. Troisièmement, dans une collaboration avec le groupe de Richard Courtemanche, nous avons étudié le lien entre la décharge neuronale et les oscillations lentes du potentiel de champ local qui sont observées dans le cervelet au repos. Nous avons constaté qu'une grande proportion de cellules de Golgi et les cellules de Purkinje sont modulées pendant les oscillations. Ces résultats indiquent que ces oscillations lentes, qui peuvent également être observées dans le cortex moteur, se propagent dans le cortex cérébelleux. Dans l'ensemble, mon travail a identifié et caractérisé un certain nombre de patrons d'activité populationnelle dans le cortex cérébelleux. L'impact de ces patrons sur le système moteur reste en grande partie à être compris et devrait faire l'objet de futures travaux

Effect of Acidithiobacillus ferrooxidans on Humic-Acid Passivation Layer on Pyrite Surface

The effect of Acidithiobacillus ferrooxidans on the humic-acid passivation layer on pyrite surfaces was studied by atomic-force microscopy, leaching experiments, and adsorption experiments. Atomic-force-microscopy results showed that humic-acid was adsorbed onto the pyrite surface. The bacteria grew and reproduced on the humic-acid layer. Leaching experiments showed that the humic-acid passivation layer prevented the oxidation of pyrite by Fe3+ under aseptic conditions. Bacteria destroyed the humic-acid layer, promoted pyrite oxidation, and increased the oxidation of pyrite from 1.64% to 67.9%. Bacterial adsorption experiments showed that the humic-acid passivation layer decreased the speed of bacterial adsorption on the pyrite surface but had no effect on the number of bacteria adsorbed on the pyrite surface. The maximum number of bacteria adsorbed by pyrite with and without the humic-acid layer was 4.17 × 1010 cells∙mL−1 and 4.4 × 1010 cells∙mL−1, respectively. Extracellular polymeric stratum layer of bacteria cultured at different concentrations of humic-acid was extracted and analyzed. This layer could destroy the humic-acid layer and promote pyrite oxidation