09-13-2006, 02:44 PM
correct answer is D. Resting tremor, rigidity, and akinesia is the triad of neurologic signs characterizing Parkinson disease. This condition is caused by degeneration and death of dopaminergic neurons in the substantia nigra that project to the striatum (nigrostriatal pathway). Striatal neurons projecting back to the substantia nigra (choice E) are not affected.