Closely Spaced MEG Source Localization and Functional Connectivity Analysis Using a New Prewhitening Invariance of Noise Space Algorithm

Figure 5

Source reconstruction using sLORETA, LCMV beamformer, and PW-INN. Source locations were the same as those in Figure 2. Real MEG noise was added such that SNR = 18. Two simulated source time courses have phase difference of 90 degrees. The correlation between sources is 0. (a)–(c) Source distribution estimated from sLORETA (a), LCMV beamformer (b), and PW-INN (c). White crosses indicate the true source locations. (d)–(f) Source time courses at the peak locations estimated from sLORETA (d), LCMV beamformer (e), and PW-INN (f). The time courses in (d)–(f) are the norm of the original time courses over -axis (i.e., collecting time courses, CTC). Bold lines in light red and light blue indicate the true source time courses and thin lines in red and blue indicate the estimated ones. The purple color line in (d) indicates the time course from the wrongly estimated equivalent source.