Long-Term BCI Training of a Tetraplegic User: Adaptive Riemannian Classifiers and User Training.

While often presented as promising assistive technologies for motor-impaired users, electroencephalography (EEG)-based Brain-Computer Interfaces (BCIs) remain barely used outside laboratories due to low reliability in real-life conditions. There is thus a need to design long-term reliable BCIs that can be used outside-of-the-lab by end-users, e.g., severely motor-impaired ones. Therefore, we propose and evaluate the design of a multi-class Mental Task (MT)-based BCI for longitudinal training (20 sessions over 3 months) of a tetraplegic user for the CYBATHLON BCI series 2019. In this BCI championship, tetraplegic pilots are mentally driving a virtual car in a racing video game. We aimed at combining a progressive user MT-BCI training with a newly designed machine learning pipeline based on adaptive Riemannian classifiers shown to be promising for real-life applications. We followed a two step training process: the first 11 sessions served to train the user to control a 2-class MT-BCI by performing either two cognitive tasks (REST and MENTAL SUBTRACTION) or two motor-imagery tasks (LEFT-HAND and RIGHT-HAND). The second training step (9 remaining sessions) applied an adaptive, session-independent Riemannian classifier that combined all 4 MT classes used before. Moreover, as our Riemannian classifier was incrementally updated in an unsupervised way it would capture both within and between-session non-stationarity. Experimental evidences confirm the effectiveness of this approach. Namely, the classification accuracy improved by about 30% at the end of the training compared to initial sessions. We also studied the neural correlates of this performance improvement. Using a newly proposed BCI user learning metric, we could show our user learned to improve his BCI control by producing EEG signals matching increasingly more the BCI classifier training data distribution, rather than by improving his EEG class discrimination. However, the resulting improvement was effective only on synchronous (cue-based) BCI and it did not translate into improved CYBATHLON BCI game performances. For the sake of overcoming this in the future, we unveil possible reasons for these limited gaming performances and identify a number of promising future research directions. Importantly, we also report on the evolution of the user's neurophysiological patterns and user experience throughout the BCI training and competition.

Lipid peroxidative damage on Cisplatin exposure and alterations in antioxidant defense system in rat kidneys: a possible protective effect of selenium.

Cisplatin (Cis-diamminedichloroplatinum II, CP) is an important chemotherapeutic agent, useful in the treatment of several cancers, but with several side effects such as nephrotoxicity. The present study investigated the possible protective effect of selenium (Se) against CP-induced oxidative stress in the rat kidneys. Male Wistar albino rats were injected with a single dose of cisplatin (7 mg CP/kg b.m., i.p.) and selenium (6 mg Se/kg b.m, as Na(2)SeO(3), i.p.), alone or in combination. The obtained results showed that CP increased lipid peroxidation (LPO) and decreased reduced glutathione (GSH) concentrations, suggesting the CP-induced oxidative stress, while Se treatment reversed this change to control values. Acute intoxication of rats with CP was followed by statistically significant decreased activity of antioxidant defense enzymes: superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione reductase (GR) and glutathione-S-transferase (GST). Treatment with Se reversed CP-induced alterations of antioxidant defense enzyme activities and significantly prevented the CP-induced kidney damage.

Phenolic compounds and biological activity of Kitaibelia vitifolia.

This study was aimed at evaluating the antioxidant activity and efficacy of the ethanolic extract of the endemic plant species Kitaibelia vitifolia in inhibiting the growth of selected fungi and bacteria. Antimicrobial activity was tested using the broth dilution procedure for determination of minimum inhibitory concentration (MIC). MICs were determined for eight selected indicator strains. The highest susceptibility to K. vitifolia ethanolic extract among the bacteria tested was exhibited by Bacillus subtilis ATCC 6633, Staphylococcus aureus ATCC 25923, and Klebsiella pneumoniae ATCC 13883 (MIC=15.62 µg/mL), followed by Escherichia coli ATCC 25922 and Proteus mirabilis ATCC 14153 (MIC=31.25 µg/mL), and Proteus vulgaris ATCC 13315 (MIC=62.50 µg/mL). Of the fungi, Candida albicans ATCC 10231 (MIC=15.62 µg/mL) showed the highest susceptibility, and Aspergillus niger ATCC 16404 (MIC=31.25 µg/mL) had the lowest. Results showed that K. vitifolia extract possesses antioxidant activity, with total antioxidant capacity of 75.45±0.68 µg of ascorbic acid/g and 50% inhibition concentration values of 47.45±0.55 µg/mL for 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity, 35.35±0.68 µg/mL for inhibitory activity against lipid peroxidation, 95.25±0.52 µg/mL for hydroxyl radical scavenging activity, and 31.50±0.35 µg/mL for metal chelating activity. Total phenolics, flavonoids, condensed tannins, and gallotannins were 85.25±0.69 mg of gallic acid (GA)/g, 45.32±0.55 mg of rutin/g, 54.25±0.75 mg of GA/g, and 41.74±0.55 mg of GA/g, respectively. The phenolic composition of K. vitifolia extract was determined by high-performance liquid chromatography. Rosmarinic acid was found to be the dominant phenolic compound of the extract.