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. Author manuscript; available in PMC: 2012 Feb 14.
Published in final edited form as: Neuroimage. 2010 Nov 1;54(4):2808–2821. doi: 10.1016/j.neuroimage.2010.10.069

Figure 4.

Figure 4

Mean and distribution of fMRI-NIRS correlations. (A) The mean and standard error of correlations between BOLD and oxy-Hb, deoxy-Hb, and total-Hb are 0.26±0.008, 0.23±0.008, and 0.19±0.008, respectively. The BOLD-oxy-Hb correlation is significantly higher than BOLD-deoxy-Hb correlation (p=2.6×10−4, paired T-test, df=1175) and the BOLD-total-Hb correlation (p<10−10). (B) The mean and standard error of the top 100 values are 0.74±0.006, 0.74±0.005, and 0.66±0.006 for oxy-, deoxy-, and total-Hb, respectively. (C,D,E) The distribution of BOLD-NIRS correlations. The percentage of high correlation (higher than 0.5) instances are 25%, 20%, and 15% for oxy-Hb, deoxy-Hb, and total-Hb, respectively. Vertical dotted lines indicate 0 NIRS-fMRI correlation. Oxy-Hb and deoxy-Hb yield similar correlations with the BOLD signal, while total-Hb shows lower correlations.