Ansa lentiformis

The superior layer of the substantia innominata of Meynert is named the ansa lenticularis (ansa lentiformis in older texts), and its fibers, derived from the medullary lamina of the lentiform nucleus, pass medially to end in the thalamus and subthalamic region, while others are said to end in the tegmentum and red nucleus.

It is classified by NeuroNames as part of the subthalamus.