Mammillary body

Gray1180 Corpus Mamillare highlighted

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Mammillary bodies are small, round bodies located on the undersurface of the brain, forming part of the diencephalon region. They are part of the limbic system, which is involved in the processing of memory and emotional responses. The mammillary bodies are connected to the hippocampus via the mammillothalamic tract and play a crucial role in memory consolidation, particularly in the conversion of short-term memory to long-term memory.

Structure

The mammillary bodies are a pair of small, round structures located at the base of the brain, posterior to the hypothalamus. Each mammillary body can be divided into two parts: the medial mammillary nucleus and the lateral mammillary nucleus. These nuclei have different connections and functions. The mammillary bodies are part of the posterior hypothalamus and are connected to various parts of the brain involved in memory and spatial memory processing.

Function

The primary function of the mammillary bodies is related to memory. They are particularly important in the recollection of past experiences. The mammillary bodies receive signals from the hippocampus via the fornix and project to the thalamus through the mammillothalamic tract. This pathway is crucial for the encoding of episodic memory. Additionally, the mammillary bodies are involved in spatial memory and navigation, likely due to their connections with the anterodorsal nucleus of the thalamus.

Clinical Significance

Damage to the mammillary bodies can lead to memory disorders. One of the most well-known conditions associated with mammillary body dysfunction is Wernicke-Korsakoff syndrome, a neurological disorder caused by thiamine (vitamin B1) deficiency, commonly seen in chronic alcoholism. This syndrome is characterized by confabulation, anterograde amnesia (inability to form new memories), and retrograde amnesia (loss of pre-existing memories).

Research

Research on the mammillary bodies has focused on their role in memory and spatial navigation. Studies involving lesions in the mammillary bodies of animals have shown deficits in spatial memory, suggesting their importance in the internal representation of the environment. Neuroimaging studies in humans have also implicated the mammillary bodies in memory processing, particularly in the context of neurological diseases that affect memory.

See Also

• Limbic System
• Memory
• Hippocampus
• Thalamus
• Wernicke-Korsakoff Syndrome