Which pathway is linked to extrapyramidal symptoms with increased acetylcholine and decreased dopamine?

• A. Nigrostriatal pathway
• B. Mesolimbic pathway
• C. Mesocortical pathway
• D. Tuberoinfundibular pathway

Answer: (A)

The nigrostriatal pathway is the one linked to extrapyramidal symptoms when acetylcholine rises relative to dopamine. This pathway runs from the substantia nigra to the striatum and is essential for normal movement control. Dopamine in the striatum normally helps inhibit acetylcholine activity; when dopamine is decreased or D2 receptors are blocked (as occurs with many antipsychotics), acetylcholine effects become relatively unchecked. That cholinergic predominance disrupts motor signaling, producing extrapyramidal symptoms such as tremor, rigidity, and slowed movements. Treatments that counter EPS often use anticholinergic medications to rebalance this neurotransmitter interaction. Other pathways, like the mesolimbic, mesocortical, and tuberoinfundibular, are associated with different aspects of psychiatric symptoms and functions, not EPS.