GRAPH ANALYSIS OF FMRI DATA
Graph analysis can be used to examine the relationships between different regions of the brain with a high degree of nuance. Below is an overview of graph analysis of fMRI data by Eleanor Collier. For a more basic intro to graph theory in general, this video series may be helpful.
If you are interested in analyzing your fMRI data with a graph theoretical approach, BRAPH is a great tool (see also this paper by the creators of BRAPH).