Figure 6.

The single-regressor NIRS model R² plotted against the reference model R² for 100 voxels selected using the value of the baseline NIRS-fMRI correlation for each voxel. The data is separated into three bands on the basis of ${\text{R}}_{\text{base}}^2$. The average increase in R² for all data points is shown in figure 6d. The value of R² between the synthetic and recovered HRFs increases as a function of ${\text{R}}_{\text{base}}^2$. The error bars in figure 6d show the standard deviation across all data points of figures 6a–6c.