Supplemental material, Supplementary for β-Oscillations Reflect Recovery of the Paretic Upper Limb in Subacute Stroke by Chih-Wei Tang, Fu-Jung Hsiao, Po-Lei Lee, Yun-An Tsai, Ya-Fang Hsu, Wei-Ta Chen, Yung-Yang Lin, Charlotte J. Stagg and I-Hui Lee in Neurorehabilitation and Neural Repair