Final answer:
Haloperidol affects dopamine activity in the basal nuclei, specifically in the substantia nigra pars compacta. It activates the direct pathway and inhibits the indirect pathway. The side effects of haloperidol primarily affect motor control and fine movements.
Step-by-step explanation:
The effects of haloperidol on the nigrostriatal pathway and tuberoinfundibular pathway in the brain are significant. Haloperidol affects dopamine activity in the basal nuclei, particularly in the substantia nigra pars compacta. The direct pathway, responsible for increasing cortical movement commands, is activated by dopamine, while the indirect pathway is inhibited by dopamine. Haloperidol's side effects primarily affect motor control and fine movements, making it a focus of attention when considering medication-related changes in motor control.