R 2007 Prefrontal involvement in imitation learning of hand actions: effects of practice and expertise Neuroimage 37 1371-83 Wahnoun R, He J and Helms Tillery S I 2006 Selection and parameterization of cortical neurons for neuroprosthetic control J. Neural Eng. 3 162-71 Walden S. Preissl H, Demandt E. Brau