Anatomical constraints on functional architecture during learning

First, we asked whether group constraints on brain activity and functional connectivity are homogeneous across brain areas, or whether some areas are more constrained than others. We hypothesized that the strongest constraints would exist primarily in sensory and motor systems, as well as in regions associated with the learning of value, as these regions are either constrained across subjects in general(sensory and motor) or are constrained because of similar leaning processes (regions associated with value learning).  We first assessed which brain regions exhibited ISC values that were significantly greater than expected (t-test, \(p<0.05\), corrected for multiple comparisons with 10000 random permutations \cite{Kemp_1997} )  across all task sessions (Fig. 2A). We observed significant ISC broadly across the occipital lobe, particularly in the lateral occipital cortex, lingual gyrus, pericalcarine, and fusiform gyrus. We also observed significant ISC among sensorimotor regions, including supramarginal gyrus, right superior frontal region, and superior motor areas. In additional analyses reported in the Supplementary Information, we verified that these same brain regions also exhibited significant ISC during each individual experimental session (Fig. S3A-B). 
Next, we assessed which brain regions exhibited ISFC values that were significantly greater than expected (t-test, \(p<0.05\), corrected for multiple comparisons) across all task sessions (Fig. 2B). We observed significant ISFC in the left frontal pole, middle and superior frontal gyri, inferior temporal gyrus, sensorimotor, temporoparietal region, anterior cingulate gyrus, amygdala, thalamus and brain regions between occipital and temporal lobes. In additional analyses reported in the Supplementary Information, we separately verified that these same brain regions exhibited significant ISFC during each individual experimental session (Fig. S3D-E). While some differences existed between in the brain regions displaying high ISC and those displaying high ISFC, in general we observed a positive correlation between regions' ISFC and ISC (r=0.45, p=0.0465). Collectively, these results suggest that some brain regions are more constrained in their activity and connectivity than others, and that, in general, similar group constraints exists on activity and connectivity.