Mammillotegmental tract in the human brain: diffusion tensor tractography study

Several animal studies have been conducted for the identification of the mammillotegmental tract (MTT); however, no study has been reported in the human brain. In the current study, using diffusion tensor tractography (DTT), we attempted to identify the MTT in the human brain. We recruited 31 healthy volunteers for this study. Diffusion tensor images were acquired using 1.5 T, and the MTT was obtained using a probabilistic tractography method based on a multi-fiber model. Values of fractional anisotropy, mean diffusivity, and tract volume of the MTT were measured. MTTs of all subjects, which originated from the mammillary body, ascended posteriorly to the bicommissural level along the third ventricle and then turned caudally and terminated at the tegmentum of the midbrain. No significant differences were observed in terms of fractional anisotropy, mean diffusivity, and tract volume according to hemisphere and sex (P < 0.05). Using DTT, we identified the MTT in the human brain. We believe that the methodology and results of this study would be helpful in research on the MTT in the human brain.