Figure 3
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Figure 3. Invariance of the ICA decomposition to changes in source distribution. Decomposition of the six same ECoG input source epochs as in Fig. 2 (a, upper left) projected through six one- and two-dipole simulated sources (c, lower left) with different locations and orientations than in the first simulation (Fig. 2c, lower left), produces a new simulated ERP data epoch (b, upper right). ICA decomposition of this new simulated data yields the ICA component waveforms shown in (d, lower right). The near-perfect correlations between each component waveform and its matching component waveform in the first simulation (Fig. 2d, lower right) are shown on the right side of (d, lower right), demonstrating that when the numbers of sources and data channels are equal, ICA decomposition is independent of the spatial distribution of the underlying sources.