Figure 3.

Analysis of centering of cardiorespiratory coordination towards 4 : 1 during exposure to red and blue color lights. (a), (c) During red light the significant negative correlation coefficient r for HRR and PCR indicates a centering towards 4 : 1. (b), (d) During blue light a centring does not occur; that is, the correlation is not significant. Note that in diagram (d) the high correlation r is spuriously caused by the outlier in the lower right part of the diagram. Dashed lines indicate average HRR_{bef_col} (and PCR_{bef_col}) and average HRR_{dur_col} − HRR_{bef_col} (and PCR_{dur_col} − PCR_{bef_col}), respectively.