One popular noninvasive method of analyzing cortical circuits at the voxel level is functional connectivity based on resting state fMRI [24]. Resting state functional connectivity (FC) has been shown to be sensitive to alterations in neural circuits in various mental disorders [25–30] as well as correlated with behavioral performance in healthy individuals [31–33]. Recent literature employing resting state fMRI based characterization of the human brain’s functional connectome suggests that resting state fMRI is grounded in underlying anatomical connections [34–37]. For example, simulations have shown that spatially distinct functional networks emerge in resting state data when they are constrained by the structural connectome [38, 39]. The close correspondence between functional and structural connectivity has also been confirmed with fMRI and diffusion tensor imaging (DTI) data [40]. This has been further confirmed in case reports of deficient inter-hemispheric functional connectivity in subjects with complete agenesis of the corpus callosum [41]. However, it is noteworthy that resting state functional connectivity can be sensitive to multi-synaptic interactions, and hence, regions that are not directly connected structurally could still be functionally connected. These data suggest
