lead to spurious EEG coherence (e.g., Fein et al., 1988; Guevara et al., 2005; Roach & Mathalon, 2008; Schiff, 2005), although these issues have an even wider impact on EEG spectral analysis (cf. Fig. 1 in Tenke & Kayser, 2005). For these reasons, the present study extends the temporal (e.g., Kayser & Tenke, 2006a) and frequency (e.g., Tenke & Kayser, 2005) CSD-PCA approach to time-frequency EEG analysis in an effort to confirm the MEG findings of Koh et al. (2011), which are also, by virtue of the imaging technique, unaffected by choice of EEG reference. However, given that our a priori hypotheses concerned alpha desynchronization, the present time-frequency analysis was restricted to low-frequency components characterizing alpha or theta, despite the ability of this unbiased, data-driven approach to concisely summarize any spectral activation pattern within the time-frequency data space.
