The subthalamus connects to the globus pallidus, a subcortical nucleus of the basal ganglia.

[2] The subthalamus is located ventral to the thalamus, medial to the internal capsule and lateral to the hypothalamus.

Caudally, the subthalamus or prethalamus is separated from the thalamus by the zona limitans intrathalamica.

[citation needed] Postnatally, the subthalamus lies beneath the thalamus, hence 'sub' (meaning below) 'thalamus'.

The subthalamus develops efferent (output) connections to the striatum (caudate nucleus and putamen) in the telencephalon, to the dorsal thalamus (medial and lateral nuclear groups) in the diencephalon, and to the red nucleus and substantia nigra in the mesencephalon.