Ranking fMRI time courses by minimum spanning trees: assessing coactivation in fMRI.
In fMRI, time courses with similar temporal "activation" patterns may belong to different brain regions (i.e., these regions are functionally connected, coactivated). A group of time courses (TCs) corresponding to a particular type of temporal activation pattern should be maximally self-consistent (homogeneous). We demonstrate that ordering a group of multidimensional fMRI time courses by a minimum spanning tree (MST) may be used to investigate the temporal homogeneity of a group of TCs. We show the utility of MST ranking for data-driven analysis methods in investigating coactivation in fMRI. MST ranking is equally useful for hypothesis-led methods. Furthermore, MST ranking enables pairwise comparisons of groups/clusters (i.e., any collection of TCs, no matter how derived) of fMRI time courses.
Baumgartner
R
R
Institute for Biodiagnostics, National Research Council Canada, 435 Ellice Avenue, Winnipeg, Manitoba, R3B 1Y6, Canada.
Somorjai
R
R
Summers
R
R
Richter
W
W
D001921:Brain / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D003198:Computer Simulation; D005385:Fingers / Q000502:physiology; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008606:Mental Processes; D008959:Models, Neurological; D009043:Motor Activity / Q000502:physiology; D013997:Time Factors