The Cz reference produced atypical results for men and null findings for women, yet this is not inconsistent with the fact that a majority of significant effects for the Cz reference in depression-related studies (e.g., 19 in the Thibodeau et al., 2006 meta-analysis) used infants or children as participants, not young adults. Only four studies with adults from the Thibodeau et al. (2006) meta-analysis demonstrated Cz-related differences in depressed groups (and two of the four consisted of small samples of middle-aged adult participants: Baehr, Rosenfeld, Baehr, & Earnest, 1998; Henriques & Davidson, 1991), whereas here we replicate larger studies that reported null results with the Cz reference in young adults (e.g., Bruder et al., 1997; Reid et al., 1998). EEG asymmetry researchers have shown that there is little convergence between Cz and other references (e.g., Hagemann et al., 2001; Reid et al., 1998) and have advocated the use of references other than Cz since variations in power at this active EEG site can distort the direction and strength of asymmetry recorded from lateral sites in either hemisphere (e.g., Davidson, 1998; Hagemann et al., 2001).
