Mathematics in Independent Component Analysis

Chapter 19. LNCS 3195:977-984, 2004 257
982 Ingo R. Keck et al.
Fig. 3. Independent component which correspond to a proposed subsystem for word
detection.
Fig. 4. Independent component with activation in Broca’s area (speech motor area).
The most interesting finding was an IC which represents a network of three
simultaneously active areas in the inferior frontal gyrus (figure 3) in one subject.
This network was suggested to be a center for the perception of speech in [8].
Figure 4 shows an IC (of the same subject) that we assume to be a network for
the decision to press the button. All other subjects except one had ICs that correspond
to these networks, although often separated into different components.
The time course of both components matches visually very well (figure 5) while
their correlation coefficient remains rather low (kcorr =0.36), apparently due to
temporary time- and baseline-shifts.