<prompt> Which of the following sites is responsible for the amnestic defect in Wernicke;s Korsakoff syndrome:Mamillary bodyThalamusPeriventricular Grey matterHippocampus  <response>: The Amnestic effect in Wernicke;s Korsakoff Syndrome is related to lesions in the dorso-medial nuclei of the thalamus. REF: Harrison book of internal medicine 21ST EDITION 