Final answer:
The correct sequence is C) Excitatory, excites, suppressing as the motor cortex's excitatory connection to the subthalamic nucleus excites the globus pallidus internal, which suppresses movement through the indirect pathway of the basal nuclei.
Step-by-step explanation:
The motor cortex has an excitatory connection to the subthalamic nucleus, which excites the globus pallidus internal, ultimately suppressing movement.
Therefore, the correct answer is C) Excitatory, excites, suppressing. In the basal nuclei of the brain, there are two main paths: the direct and indirect pathways. The indirect pathway involves the striatum projecting to the globus pallidus external segment (GPe), then to the subthalamic nucleus (STN), and finally to the globus pallidus internal segment (GPi) or substantia nigra pars compacta (SNr).
The end result of this pathway is the inhibition of the thalamus, which in turn decreases cortical control of movement, thus suppressing movement. Contrastingly, the direct pathway causes the disinhibition of the thalamus, leading to increased cortical control of movement and promoting movement.