Lateral perspective of deep white matter tracts. The superior longitudinal fasciculus is a major association tract of the brain located lateral to the corona radiata.  It connects the frontal lobe with the ipsilateral parietal, temporal and occipital lobes. The sagittal stratum is a major cortico-subcortical white matter bundle situated deep to the superior longitudinal fasciculus and lateral to the tapetum of the corpus callosum. It is a neural crossroad traversed by several white matter tracts, including, the middle and inferior longitudinal fasciculi, the inferior fronto-occipital fasciculus, and the optic radiations.  The external capsule lies lateral to the sagittal stratum, sandwiched in between the putamen and claustrum.  The dorsal part of the external capsule contains corticoclaustral fibers, while its ventral part contains the uncinate fasciculus and inferior fronto-occipital fasciculus.  (Image courtesy of PA Rubino)