Neurodegenerative Diseases USMLE Step 1 Practice Question
A 71-year-old woman presents with a 3-year history of progressive memory loss. She repeatedly asks the same questions, frequently misplaces objects, and has become lost while driving in previously familiar neighborhoods. Vital signs are stable (BP 138/82, HR 78, RR 16, Temp 37°C). Mini-Cog score is 2/3. MRI brain shows hippocampal atrophy without focal lesions. Neurologic examination is otherwise normal; gait and tremor are absent. Which neurotransmitter system is most depleted in this disorder?
Answer choices
- ADopamine in the substantia nigra
- BGlycine in the ventral horn
- CAcetylcholine in the nucleus basalis of MeynertCorrect answer
- DSerotonin in the raphe nuclei
- EGamma aminobutyric acid in the caudate
- FGlutamate in the hippocampal CA1 pyramidal neurons
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