Fig. 4: The distribution of marmoset olfactory nerves depicted by diffusion tensor tractography (DTT).

a DTT was performed using the whole skull of a marmoset. The reconstructed three-dimensional images show oblique-sagittal, coronal and axial views. The colored fibers were visualized with DTT, and b0 images were used as the background images. The olfactory bulbs of the marmoset were set as the region of interest (ROI) so that the depicted fibers reflected the neurons projecting from the nasal cavity to the olfactory bulbs. The fibers are color-coded according to their directionality: anterior-posterior axis, blue; medial-lateral axis, red; and superior-inferior axis, green. A anterior, L lateral, M medial, P posterior. b Oblique-sagittal views of the fiber tracts projecting from the main anatomical structures in the nasal cavity. The nerve tracts identified by DTT were color-coded according to the structure selected as the ROI (septum, middle turbinate, nasoturbinate or superior turbinate). MT middle turbinate, NT nasoturbinate, ST superior turbinate. c The track counting function of TrackVis was used to measure the density of fibers distributed in the septum and turbinates. Each value is expressed as the percentage of the total track counts. Bars show the mean and standard deviation. Individual data points are shown in dots (n = 10; 10 nasal cavities from 5 biologically independent specimens). d The percentage of all track counts of the fibers distributed to each of the turbinates. MT middle turbinate, NT nasoturbinate, ST superior turbinate. Bars show the mean and standard deviation. Individual data points are shown in dots (n = 10; 10 nasal cavities from 5 biologically independent specimens). ***p < 0.001.