Brain-Computer Interface: comparison of two control modes to drive a virtual robot

A Brain-Computer Interface (BCI) is a system that enables communication and control that is not based on muscular movements, but on brain activity. Some of these systems are based on discrimination of different mental tasks; usually they match the number of mental tasks to the number of control commands. Previous research at the University of Málaga (UMA-BCI) have proposed a BCI system to freely control an external device, letting the subjects choose among several navigation commands using only one active mental task (versus any other mental activity). Although the navigation paradigm proposed in this system has been proved useful for continuous movements, if the user wants to move medium or large distances, he/she needs to keep the effort of the MI task in order to keep the command. In this way, the aim of this work was to test a navigation paradigm based on the brain-switch mode for ‘forward’ command. In this mode, the subjects used the mental task to switch their state on /off: they stopped if they were moving forward and vice versa. Initially, twelve healthy and untrained subjects participated in this study, but due to a lack of control in previous session, only four subjects participated in the experiment, in which they had to control a virtual robot using two paradigms: one based on continuous mode and another based on switch mode. Preliminary results show that both paradigms can be used to navigate through virtual environments, although with the first one the times needed to complete a path were notably lower.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Études des modifications de la réponse apoptotique induites par le virus de l'hépatite C dans des foies normaux et infectés et dans la lignée cellulaire HuH7 contenant ou non un réplicon sous-génomique du virus

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal

Introduction of statistical information in a syntactic analyser for document image recognition

International audienceThis paper presents an improvement to document layout analysis systems, oering a possible solution to Sayre's paradox (which states that an element must be recognized before it can be segmented; and it must be segmented before it can be recognized). This improvement, based on stochastic parsing, allows integration of statistical information, obtained from recognizers, during syntactic layout analysis. We present how this fusion of numeric and symbolic information in a feedback loop can be applied to syntactic methods to improve document description expressiveness. To limit combinatorial explosion during exploration of solutions, we devised an operator that allows optional activation of the stochastic parsing mechanism. Our evaluation on 1250 handwritten business letters shows this method allows the improvement of global recognition scores

How to Improve and Refine the Elevated Plus Maze for Laboratory Mice

peer reviewedThe daily light-dark cycles synchronize behavioural and physiological processes to the external environment. Light is the most important environmental cue that coordinates many aspects such as activity, maintenance behaviours, hormonal regulation or long-term potentiation. Mice are among the main animals used in behavioural neuroscience and preclinical research laboratories. Although nocturnal, they are generally tested during day (i.e. during their resting phase). Even if convenient for the experimenter, a perturbation of the sleep-wake cycle such as manipulations during day can generate some stress to the animal, produce few reliable data, contributing to reproducibility issue, and may lead to negative consequences for health, physiology, behaviour and cognition. Then the testing moment could be an important variable affecting animal behavior. It appears that rodents are less anxious during the dark phase, however, a lack of data regarding the effect the testing moment on behavior has recently been highlighted. Additionally, several studies evaluating the effects of the testing moment have shown conflicting results; these differences can be explained by various methodological aspects such as parameters related to the procedure but also by the way of collecting and interpreting behavioral data. In this study, we focused on an anxiety test. We tested 4 different testing moment to determine if there is a more appropriate testing moment where mice show the less anxiety. Previously, we have shown that the way of analyzing behavior can affect the results. Here, we refined our observation method to improve the data interpretation

Evaluation of three broth microdilution systems to determine colistin susceptibility of Gram-negative bacilli

The broth microdilution (BMD) method is currently the recommended technique to determine susceptibility to colistin.Objectives: We evaluated the accuracy of three commercialized BMD panels [Sensititre (ThermoFisher Diagnostics), UMIC (Biocentric) and MicroScan (Beckman Coulter)] to determine colistin susceptibility.Methods: A collection of 185 isolates of Gram-negative bacilli (133 colistin resistant and 52 colistin susceptible) was tested. Manual BMD according to EUCAST guidelines was used as the reference method, and EUCAST 2017 breakpoints were used for susceptibility categorization.Results:The UMIC system gave the highest rate of very major errors (11.3%) compared with the Sensititre and MicroScan systems (3% and 0.8%, respectively). A high rate of major errors (26.9%) was found with the MicroScan system due to an overestimation of the MICs for the non-fermenting Gram-negative bacilli, whereas no major errors were found with the Sensititre and UMIC systems.Conclusions: The UMIC system was easy to use, but failed to detect >10% of colistin-resistant isolates. The MicroScan system showed excellent results for enterobacterial isolates, but non-susceptible results for non- fermenters should be confirmed by another method and the range of MICs tested was narrow. The Sensititre system was the most reliable marketed BMD panel with a categorical agreement of 97.8%

Time to switch off lights? Effects of testing moment in the circadian sleep-wake rhythm

peer reviewedThe daily light-dark cycle allows the synchronization of behavioural and physiological processes to the external environment. Light is the most important environmental cue or zeitgeber that coordinate many aspects of physiology and behaviour such as activity, maintenance behaviours, alertness, body temperature, hormonal regulation or long-term potentiation (i.e. a process that plays a key role in memory consolidation). Mice are among the main animals used in behavioural neuroscience and preclinical research laboratories. Although they are nocturnal animals, mice are generally tested during day (i.e. their resting phase). Thus, the testing moment might be a predominant variable that can affect animal behaviour and cognition and from there, all the inferences we make about behavioural and cognitive processes. In this study, several behavioural and cognitive components such as activity, motivation, learning and behavioural flexibility have been evaluated. We assumed that C57/BL6 mice should perform better and show higher activity rate while tested during night. Although we didn’t find any differences between testing conditions in behavioural or cognitive performance, several factors can explain this absence of effects such as nature of the task, presence of zeitgeber, modulation of arousal, light pollution as well as light conditions during the test itself

Assessment of executive functions in mice with the Fixed-Ratio schedule of reinforcement

The simplest operant schedule of reinforcement is the Fixed Ratio (FR). In this task, animals must provide a determined number of responses (i.e., a ratio of responses) to obtain each food reward. In FR1, a single response is required, 2 responses in a FR2, 5 in a FR5 and so on. The FR is often used only to shape the operant response before to go further with another task, but of course, it can be used with more interesting goals. Classically, measures such as inter-responses time (IRT), latency to collect the delivered food reward, response or reward rate, but also post reinforcement pause are collected. Together, they allow to obtain information about motor ability, learning and motivation. However, there is a lack of interest in the executive aspect potentially implied by the FR3, especially in situations where the ratio is held constant across multiple training sessions. Indeed, in such situations, as training progress the subject can learn that a certain quantity of responses is required before the reward is available. And hence, checking the food tray to see if the reward is available should be more probable as the animal progress in the ratio. With this operant procedure, it seems therefore possible to investigate the animal’s executive function. In this study, we thus focused on the premature head entries into the empty food tray (PHE, i.e., when the reward was not delivered yet) and their evolution across sessions of FR30. The analysis of the distribution of PHE could offer a way to analyze the subject’s ability to optimize its operant behavior. We also compared this aspect of the operant behavior between young and old mice as the age is factor affecting the executive function

Numerical modelling of the sediment dynamics in Saint-Martin-la-Porte reservoir, France

Water Qualit