Review Question - QID 109603

A 20-year-old male is brought to a psychiatrist by his parents for bizarre behavior. His parents report that over the past two semesters in school, his personality and behavior have changed noticeably. He refuses to leave his room because he believes people are spying on him. He hears voices that are persecutory and is convinced that people at school have chips implanted in their brains to spy on him. Screenings for depression and mania are negative. His past medical history is unremarkable. His family history is notable for a maternal uncle with bipolar disorder. He does not drink alcohol or smoke. His temperature is 98.8°F (37.1°C), blood pressure is 115/70 mmHg, pulse is 85/min, and respirations are 18/min. On examination, he appears to be responding to internal stimuli. Which of the following pathways is primarily responsible for these symptoms?