Fig. 3.

Segmentation of the thalamus according to probabilistic tractography streamlines seeded in various cortical ROIs. Segmentation was made using unilateral ROIs in the somatosensory, visual, motor, auditory and the ventrolateral cortices (Supp. Fig. 1). A–C, Wholebrain CSD at 1 streamline seeded per voxel failed to map the entire thalamus, unlike 50 streamlines seeded per voxel (D–F). The same ROIs were employed for segmentation using the FSL ROI tractography approach seeded at 500 streamlines per voxel (G–I) or 5000 streamlines per voxel (J–L). Under the conditions employed, CSD probabilistic tractography produces a hard segmentation of the entire thalamic ROI, unlike FSL probabilistic tractography. Segmentation of the thalamic ROI by CSD probabilistic tractography follows the anatomical cortico-thalamic topography. The coronal plane shown correlates to Bregma - 2.06 mm, the sagittal plane corresponds to 2mm from the midline, and the horizontal plane corresponds to 2.5 mm from the interaural line from the mouse brain atlas (Franklin and Paxinos, 1997). The inserts are at 4× zoom. For similar planes, scale bars = 1 mm.