Voxels in the default mode network (DMN) show the highest agreement between structural and functional connectivity in the human brain. Using fMRI and DTI data, structural connectivity was measured with probabilistic and global fiber-tracking, while functional connectivity used full and partial correlations of voxel timecourses. Bilateral precuneal and inferior parietal regions were identified by all methods; global tracking additionally revealed medial prefrontal cortices and early visual areas. Full and partial correlations yielded no significant differences. The DMN appears to use the most direct structural connections, suggesting the brain's anatomy shapes its functional repertoire.
Subcortical arousal systems help control sustained changes in attention and conscious awareness, and recent studies suggest they also influence short-term dynamic modulation of visual attention, but their role across sensory modalities is unclear. Analyzing fMRI data from 1561 participants performing visual, auditory, tactile, and taste perception tasks, a shared circuit of subcortical arousal systems was identified. This circuit shows early transient increases in activity in the midbrain reticular formation and central thalamus across all sensory modalities, with less consistent increases in the pons, hypothalamus, basal forebrain, and basal ganglia. Identifying these networks is critical for understanding normal attention and consciousness and may aid subcortical targeting for therapeutic neuromodulation.