Functional vs anatomical cortico-striatal connectivity in the macaque brain.

The cerebral cortex provides the main input to the striatum, constituting the first step in cortico-basal ganglia loops. Decades of careful anatomical tract-tracing research have established the exquisite topography of each cortical region's projection to the striatum in nonhuman primates. In parallel, neuroimaging research has demonstrated the relationship between cortico-striatal resting-state functional connectivity and specific cognitive, behavioral, psychiatric, and neurological states in humans. However, still unclear is the extent to which functional connectivity recapitulates the specific topographies of cortico-striatal anatomical connectivity. Here, we combined datasets of cortico-striatal anatomical and functional connectivity in macaques to determine the degree of overlap between the two. Across multiple metrics of similarity, we found that anatomical and functional connectivity demonstrated higher correspondence in the frontal and primary somatosensory cortices, with lower correspondence in other brain regions. This suggests that there are many regions in the brain in which cortico-striatal functional connectivity may not be driven by direct anatomical connectivity.