Subthalamic nucleus, one on hay. and one on the left. side, belongs to the midbrain (diencephalon) and is located below the thalamus itself in the subthalamus region at the transition downward towards the midbrain (mesencephalon). The nucleus is counted among the basal ganglia and is excitatory with a tonic eigenfrequency of 20 Hz.
The subthalamic nucleus receives excitatory (glutamate-ergic) signals partly from the thalamus (CM-PF complex) and partly from the cerebral cortex, especially the frontal lobe, and drives GPi-SNr which has a slowing effect on the thalamus.
The subthalamic nucleus is included as a switching center both in the "Hyperdirect Pathway" and in the "Indirect Pathway" through the basal ganglia towards the thalamus.