Fig. 3

The SNR profile of the data records. (a) The change in SNRs with respect to the stimulus frequency. (b) The change in SNRs with respect to the block number in the experiment. (c) The joint and marginal distributions of SNRs and ages. (d) An overview of a representative participant with high SNR. In this case, the SNRs were distributed toward high values and there was a pattern of dense distribution in the occipital region. (e) An overview of a representative participant with low SNR. In this case, the histogram has a distribution of low SNRs and no specific pattern could be observed in the topographic maps. In (d) and (e), upper left panel: topographic maps of SNR; bottom left panel: temporal waves of average SSVEPs; middle panel: topographic maps of spectral amplitude at the fundamental frequency, 2nd, 3rd and 4th harmonics; right panel: histogram of SNRs. Note that (a), (b) and (c) are from all participants and all trials, while (d) and (e) are from all trials for a specific participant. (Best view in color).