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. 2004 Jun 2;24(22):5269–5282. doi: 10.1523/JNEUROSCI.5626-03.2004

Figure 2.

Figure 2.

A, Data processing stream. Ten-channel EMGs filtered by RMS 40-point moving average were down-sampled to 250 Hz, periods of inactivity were excised, and activity periods were concatenated. The resultant 10 × 262,144 matrix of EMG data (>1000 sec of activity) was subject to ICA. The mixing matrix and 10 activation time courses were then analyzed. B, Top left, Raw EMG. Top right, Sample raw EMG and filtered EMG on expanded ordinate and time scale. Bottom left, Rectified EMGs (E) after filtering. Bottom right, These are a linear combination of IC activations (C). W is a 10 × 10 matrix, called the mixing matrix, transforming components C into EMG E: E = WC. Some EMG traces outlined in gray at the left are similar. Much of this similarity comes from the first ICA component in the activations on the right. Muscles are numbered left 1–5 and right 6–10 from top to bottom. Component 1 projects heavily to muscles 3, 6, 7, and 8 (shaded and outlined; left). The muscles are ordered: 1, rectus anticus (RA); 2, rectus internus (RI); 3, adductor magnus (AD); 4, semimembranosus (SM); 5, gluteus (GL); 6, vastus internus (VI); 7, biceps femoris (illiofibularis) (BI); 8, sartorius (SA); 9, vastus externus (VE); 10, semitendinosus (ST).