Towards Zero Training for Brain-Computer Interfacing

Electroencephalogram (EEG) signals are highly subject-specific and vary considerably even between recording sessions of the same user within the same experimental paradigm. This challenges a stable operation of Brain-Computer Interface (BCI) systems. The classical approach is to train users by neurofeedback to produce fixed stereotypical patterns of brain activity. In the machine learning approach, a widely adapted method for dealing with those variances is to record a so called calibration measurement on the beginning of each session in order to optimize spatial filters and classifiers specifically for each subject and each day. This adaptation of the system to the individual brain signature of each user relieves from the need of extensive user training. In this paper we suggest a new method that overcomes the requirement of these time-consuming calibration recordings for long-term BCI users. The method takes advantage of knowledge collected in previous sessions: By a novel technique, prototypical spatial filters are determined which have better generalization properties compared to single-session filters. In particular, they can be used in follow-up sessions without the need to recalibrate the system. This way the calibration periods can be dramatically shortened or even completely omitted for these ‘experienced’ BCI users. The feasibility of our novel approach is demonstrated with a series of online BCI experiments. Although performed without any calibration measurement at all, no loss of classification performance was observed

Spatial Orientation in Japanese Quails (Coturnix coturnix japonica)

Finding a given location can be based on a variety of strategies, for example on the estimation of spatial relations between landmarks, called spatial orientation. In galliform birds, spatial orientation has been demonstrated convincingly in very young domestic chicks. We wanted to know whether adult Japanese quails (Coturnix coturnix japonica) without food deprivation are also able to use spatial orientation. The quails had to learn the relation of a food location with four conspicuous landmarks which were placed in the corners of a square shaped arena. They were trained to find mealworms in three adjacent food cups in a circle of 20 such cups. The rewarded feeders were located during training between the same two landmarks each of which showed a distinct pattern. When the birds had learned the task, all landmarks were displaced clockwise by 90 degrees. When tested in the new situation, all birds redirected their choices with respect to the landmark shift. In subsequent tests, however, the previously correct position was also chosen. According to our results, quails are using conspicuous landmarks as a first choice for orientation. The orientation towards the previously rewarded location, however, indicates that the neuronal representation of space which is used by the birds also includes more fine grain, less conspicuous cues, which are probably also taken into account in uncertain situations. We also presume that the rare orientation towards never rewarded feeders may be due to a foraging strategy instead of being mistakes

Downregulation of microRNA-34a* in rheumatoid arthritis synovial fibroblasts promotes apoptosis resistance

OBJECTIVE: We investigated the expression and the impact of the microRNA-34 (miR-34) family on apoptosis in synovial fibroblasts (SF) of rheumatoid arthritis (RA) patients. METHODS: Expression of the miR-34 family was analyzed by real-time PCR in SF with or without stimulation with Toll-like receptor (TLR) ligands, TNF-α, IL-1β, hypoxia and 5-azacytidine. Promoter methylation was studied by combined bisulfite restriction analysis. Overexpression and silencing of miR-34a and miR-34a* was used to analyze their effect on apoptosis by annexin V/PI staining. Production of XIAP (X-linked inhibitor of apoptosis protein) was analyzed by real-time PCR and immunohistochemistry. Reporter gene assay was used to study the signaling pathways of miR-34a*. RESULTS: Basal expression levels of miR-34a*, but not of miR-34a, miR-34b/b* and miR-34c/c*, were found to be reduced in SF from RA compared to osteoarthritis. Neither TNF-α, IL-1β, TLR ligands nor hypoxia altered miR-34a* expression. However, we identified the promoter of miR-34a/34a* to be methylated and showed that transcription of the miR-34a duplex is induced upon treatment with demethylating agents. Enforced expression of miR-34a* led to an increased rate of FasL and TRAIL mediated apoptosis in RASF. Moreover, levels of miR-34a* highly correlated with the expression of XIAP, which was found to be upregulated in RA synovial cells. Finally, our study identified XIAP as a direct target of miR-34a*. CONCLUSION: Our data provide evidence for a methylation specific downregulation of pro-apoptotic miR-34a* in RASF. Decreased expression of miR-34a* results in upregulation of its direct target XIAP, thereby contributing to apoptosis resistance of RASF