This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Psychiatry
The site of lesion in korsakoff psychosis is 
Select and explain. 
A. Frontal lobe, B. Corpus striatum, C. Mamillary body, D. Cingulated gyrus
C: Mamillary body
Answer: C: Mamillary body 
Explanation: Wernicke-Korsakoff syndrome is associated with periventricular lesions surround the third ventricle, aqueduct, and fouh ventricle, with petechial haemorrhages in occasional acute cases and atrophy of the mammillary bodies in most chronic cases. There is frequently endothelial proliferation, demyelination, and some neuronal loss. These changes may be detected by MRI scanning. The amnestic defect is related to lesions in the dorsalmedial nuclei of the thalamus. Reference: Harrison19e pg: 1783