Mammillotegmental fasciculus
The mammillotegmental fasciculus (mammillotegmental tract, or mammillotegmental bundle of Gudden) is a small bundle of efferent fibers from the hypothalamus running from the mammillary body to the tegmentum. Its functions are not well defined for humans, but based on animal studies it seems to be related to regulating visceral function and processing spatial information.
Source: Wikipedia — Mammillotegmental fasciculus (CC BY-SA 4.0)