Quantitative mapping of diffusion characteristics under the cortical surface.

Recent studies have demonstrated regional segregations on several peripheral white matter (WM) regions, which may imply different anatomical or functional characteristics [Cereb Cortex 17(4) 2007 816-25; Neuroimage 37(2) 2007 599-610; J Cogn Neurosci 16(7) 2004 1227-33]. Nonetheless, little is known about overall patterns of peripheral WM across the regions. In this study, diffusion tensor imaging with 2-mm isovoxel resolution and cortical surface mapping were combined to determine peripheral WM structure. Fractional anisotropy (FA) mapping showed consistent regional patterns across the young normal subjects while significant high or low FA values were shown in the motor-somatosensory cortex, prefrontal cortex, temporal, and medial occipital cortex. By adopting both region of interest and connectivity analysis, results were then discussed with structural network properties as well as WM maturation process.