Motor imagery-based brain-computer interfaces (MI-BCIs) rely on interactions between humans and machines. Therefore, the (learning) characteristics of both components are key to understand and improve performances. Data-driven methods are often used to select/extract features with very little neurophysiological prior. Should such approach include prior knowledge and, if so, which one? This paper studies the relationship between BCI performances and characteristics of the subject-specific Most Discriminant Frequency Band (MDFB) selected by a popular heuristic algorithm. First, our results showed a correlation between the selected MDFB characteristics (mean and width) and performances. Then, to investigate a possible causality link, we compared, online, performances obtained with a constrained (enforcing characteristics associated to high performances) and an unconstrained algorithm. Although we could not conclude on causality, average performances using the constrained algorithm were the highest. Finally, to understand the relationship between MDFB characteristics and performances better, we used machine learning to 1) predict MI-BCI performances using MDFB characteristics and 2) select automatically the optimal algorithm (constrained or unconstrained) for each subject. Our results revealed that the constrained algorithm could improve performances for subjects with either clearly distinct or no distinct EEG patterns.

Serum IgM has been shown to participate in the control of IgG autoreactivity in healthy subjects. We have recently shown that an immunoglobulin preparation of pooled normal human IgM (IVIgM) contains anti-idiotypic antibodies against disease-associated IgG autoantibodies in autoimmune patients and protects rats from experimental autoimmunity. The aim of the present study was to asses the in vitro and in vivo immunomodulatory effects of IVIgM in comparison with IgG, in SCID mice reconstituted with thymic cells from a myasthenia gravis patient. Non-leaky SCID mice were injected i.p. with 60 x 10(6) thymic cells from a patient with myasthenia gravis and 1 day later boosted with 10(6) irradiated acetylcholine receptor (AchR)-expressing TE671 cells. On days 14, 21 and 28, mice were treated with IVIgM or with equimolar amounts of human serum albumin. The level of anti-AchR antibodies in the sera of three out of four IgM-treated animals was less than 1 nM. Further, there was a significant decrease in the loss of endplate AchR on the diaphragms of IgM-treated SCID mice. These findings indicate that pooled normal IgM exerts an immunoregulatory role in experimental myasthenia gravis, and suggests that IgM may be considered as an alternative approach in the therapy of autommune diseases.

Serum IgM has been shown to participate in the control of IgG autoreactivity in healthy subjects. We have recently shown that an immunoglobulin preparation of pooled normal human IgM (IVIgM) contains anti‐idiotypic antibodies against disease‐associated IgG autoantibodies in autoimmune patients and protects rats from experimental autoimmunity. The aim of the present study was to asses the in vitro and in vivo immunomodulatory effects of IVIgM in comparison with IgG, in SCID mice reconstituted with thymic cells from a myasthenia gravis patient. Non‐leaky SCID mice were injected i.p. with 60 × 106 thymic cells from a patient with myasthenia gravis and 1 day later boosted with 106 irradiated acetylcholine receptor (AchR)‐expressing TE671 cells. On days 14, 21 and 28, mice were treated with IVIgM or with equimolar amounts of human serum albumin. The level of anti‐AchR antibodies in the sera of three out of four IgM‐treated animals was less than 1 nM. Further, there was a significant decrease in the loss of endplate AchR on the diaphragms of IgM‐treated SCID mice. These findings indicate that pooled normal IgM exerts an immunoregulatory role in experimental myasthenia gravis, and suggests that IgM may be considered as an alternative approach in the therapy of autommune diseases.