Mammillary body explained

Mammillary body
Latin:corpus mamillare
(plural: corpora mamillaria)
Ispartof:Diencephalon
System:Limbic
Components:medial mammillary nucleus
lateral mammillary nucleus
Acronym:mmb

The mammillary bodies are a pair of small round bodies, located on the undersurface of the brain that, as part of the diencephalon, form part of the limbic system. They are located at the ends of the anterior arches of the fornix.[1] They consist of two groups of nuclei, the medial mammillary nuclei and the lateral mammillary nuclei.[2]

Neuroanatomists have often categorized the mammillary bodies as part of the posterior part of hypothalamus.[3]

Structure

Connections

They are connected to other parts of the brain (as shown in the schematic, below left), and act as a relay for impulses coming from the amygdalae and hippocampi, via the mamillo-thalamic tract to the thalamus.

Function

Mammillary bodies, and their projections to the anterior thalamus via the mammillothalamic tract, are important for recollective memory.[4] According to studies of rats with mammillary body lesions, damage to the medial mammillary nucleus lead to spatial memory deficits.[4]

Clinical significance

Damage to the mammillary bodies due to thiamine deficiency is implied in pathogenesis of Wernicke–Korsakoff syndrome. Symptoms include impaired memory, also called anterograde amnesia, suggesting that the mammillary bodies may be important for memory. Lesions of the medial dorsal and anterior nuclei of the thalami and lesions of the mammillary bodies are commonly involved in amnesic syndromes in humans.[5]

Mammillary body atrophy is present in several other conditions, such as colloid cysts in the third ventricle, Alzheimer's disease, schizophrenia, heart failure, and sleep apnea. In spite of this the exact function of the mammillary bodies is still not clear.[4]

See also

External links

Notes and References

  1. Web site: Mammillary Bodies . Springer Reference . 2013-06-03.
  2. Vann SD, Aggleton JP . The mammillary bodies: two memory systems in one? . Nature Reviews. Neuroscience . 5 . 1 . 35–44 . January 2004 . 14708002 . 10.1038/nrn1299 . 15027244 . .
  3. M.B. Carpenter and J. Sutin: Human Neuroanatomy (8th edition) 1983
  4. Vann SD . Re-evaluating the role of the mammillary bodies in memory . Neuropsychologia . 48 . 8 . 2316–27 . July 2010 . 19879886 . 10.1016/j.neuropsychologia.2009.10.019 . 10.1.1.372.1373 . 2424758 .
  5. Duprez TP, Serieh BA, Raftopoulos C . Absence of memory dysfunction after bilateral mammillary body and mammillothalamic tract electrode implantation: preliminary experience in three patients . AJNR. American Journal of Neuroradiology . 26 . 1 . 195–7; author reply 197–8 . January 2005 . 15661728 . 7975039 .