At the base of the brain, there are right and left mammillary bodies. These also go by their Latin name, corpus mamillare. Each “body” has a round and smooth shape. They are part of the limbic system.

Each mammillary body joins the pretectum, thalamus, and other parts to make up the greater diencephalon part of the brain. These bodies are connected directly to the brain, and they relay impulses to the thalamus. The overall route, from the amygdalae to the thalamus, is often referred to as the Papez circuit.

Along with the dorsomedial and anterior nuclei of the thalamus, each mammillary body plays in active role in how recognitional memory (like seeing someone’s face and remembering you’ve met before) is processed. Some believe the bodies add sensory smell detail to stored memories.

Memory loss could result from damage to either mammillary body. Typically, damage results from prolonged thiamine (vitamin B1) shortages in the body. Some symptoms and complications of Wernicke-Korsakoff syndrome may also play a role. Wernicke-Korsakoff syndrome is a spectrum of brain disorders caused by thiamine deficiency. This is usually the result of alcoholism. Wernicke encephalopathy is an earlier stage of Korsakoff’s syndrome. Symptoms include loss of muscle coordination, vision problems, memory loss, and inability to form new memories.