Mammillothalamic tract in human brain: diffusion tensor tractography study

Abstract

The mammillothalamic tract (MTT) is a part of the Papez circuit and connects the mammillary body and anterior thalamus. No studies of the MTT have been performed using diffusion tensor tractography (DTT). In the current study, we attempted to identify the MTT in the human brain using DTT. We recruited 25 healthy volunteers for this study. Diffusion tensor images (DTIs) were scanned using 1.5-T, and the MTT was obtained using FMRIB software. Values of fractional anisotropy (FA), mean diffusicity (MD), and tract volume of the MTT were measured. The location of the highest probability point of the MTT was measured at the bicommissural level. MTTs of all subjects, which originated from the mammillary body, ascended posteriorly to the bicommissural level, along the third ventricle, and then ascended to the anterior thalamus in the antero-lateral direction. Average location of the MTT was 37.15% from the most posterior border of the anterior commissure to the most posterior border of the third ventricle at the bicommissural level. We identified the MTT in the human brain using DTT. These methods and results would be helpful to both clinicians and researchers in this field.