Table 2.

Information obtained from an IC output by FLICA.

Parameters	Meaning	Utility in this study
IC value	IC value: representing the weight of each subject's intensity explained by the corresponding IC	Used to find out the IC that has the strongest negative relationship with age (see results in Section 3.1.1)
SI	Spatial information: representing the regions that correspond to each IC (Figure 1)	Used to define initial brain regions
VV	Voxel value: the probability operation results of each voxel within the regions of IC (Figure 1)	-
σ	The thresholds of VV	Used to determine the more accurate age-related regions (see details in Section 2.4.2)