A 32-year-old woman with Urbach-Wiethe disease has selective bilateral calcification of the amygdala. On testing she cannot acquire conditioned fear responses to a tone previously paired with an electric shock, although her declarative memory for the tone-shock pairing is intact. Which structure accounts for her preserved declarative memory?

• A Caudate nucleus
• B Hippocampus ✓
• C Cingulate gyrus
• D Mammillary body

Explanation

Fear conditioning depends on the lateral amygdala, whose damage abolishes conditioned autonomic fear responses. Declarative knowledge of the pairing depends on the medial temporal lobe memory system centered on the hippocampus, which is intact here, giving a clean double dissociation. The caudate mediates habit learning, the cingulate participates in attention and emotion expression, and mammillary body damage causes anterograde amnesia rather than loss of fear conditioning.

Reference: Kandel, Principles of Neural Science, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.