Following a brain injury, a patient can accurately describe events from several years earlier but cannot remember conversations that occurred after the injury. Over repeated trials, the patient nevertheless improves at a new motor task without remembering having practiced it. Damage to which brain structure most likely produced this pattern of deficits?
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Answer: C (Hippocampus)
The patient retains previously formed memories but cannot form new declarative memories, indicating anterograde amnesia. The hippocampus is required for the consolidation of new declarative memories, so damage to this structure best explains the deficit. Improvement on the motor task shows that procedural learning remains intact. The amygdala primarily processes emotional significance, the basal ganglia contribute to movement and procedural learning, and the medulla oblongata regulates vital autonomic functions.