A 62-year-old man is evaluated for progressive slowness and difficulty initiating voluntary movements. He reports that when he tries to start walking, it feels like his feet are “stuck to the floor.” Neurologic examination shows bradykinesia and decreased facial expression. A researcher explains to the patient that some of his symptoms can be understood by reduced activity in a basal ganglia circuit that normally facilitates movement by disinhibiting the thalamus.

Which of the following sequences of neurotransmitters and effects best describes the key synaptic steps in this movement-facilitating (direct) pathway from motor cortex to thalamus?

(Assume ipsilateral connections.)