Mammillary body
Encyclopedia
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. They consist of two groups of nuclei, the medial mammillary nuclei and the lateral mammillary nuclei.
Neuroanatomists have often categorized the mammillary bodies as part of the hypothalamus
.
e and hippocampi
, via the mamillo-thalamic tract to the thalamus
.
This circuit, from amygdalae to mammillary bodies, and then on to the thalamus, is part of the larger 'Papez circuit
'.
They are believed to add the element of smell to memories.
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.
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...
, that, as part of the diencephalon
Diencephalon
The diencephalon is the region of the vertebrate neural tube which gives rise to posterior forebrain structures. In development, the forebrain develops from the prosencephalon, the most anterior vesicle of the neural tube which later forms both the diencephalon and the...
form part of the limbic system
Limbic system
The limbic system is a set of brain structures including the hippocampus, amygdala, anterior thalamic nuclei, septum, limbic cortex and fornix, which seemingly support a variety of functions including emotion, behavior, long term memory, and olfaction. The term "limbic" comes from the Latin...
. They are located at the ends of the anterior arches of the fornix. They consist of two groups of nuclei, the medial mammillary nuclei and the lateral mammillary nuclei.
Neuroanatomists have often categorized the mammillary bodies as part of the hypothalamus
Hypothalamus
The Hypothalamus is a portion of the brain that contains a number of small nuclei with a variety of functions...
.
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 amygdalaAmygdala
The ' are almond-shaped groups of nuclei located deep within the medial temporal lobes of the brain in complex vertebrates, including humans. Shown in research to perform a primary role in the processing and memory of emotional reactions, the amygdalae are considered part of the limbic system.-...
e and hippocampi
Hippocampus
The hippocampus is a major component of the brains of humans and other vertebrates. It belongs to the limbic system and plays important roles in the consolidation of information from short-term memory to long-term memory and spatial navigation. Humans and other mammals have two hippocampi, one in...
, via the mamillo-thalamic tract to the thalamus
Thalamus
The thalamus is a midline paired symmetrical structure within the brains of vertebrates, including humans. It is situated between the cerebral cortex and midbrain, both in terms of location and neurological connections...
.
This circuit, from amygdalae to mammillary bodies, and then on to the thalamus, is part of the larger 'Papez circuit
Papez circuit
Described by James Papez in 1937, the Papez circuit of the brain is one of the major pathways of the limbic system and is chiefly involved in the cortical control of emotion. The Papez circuit plays a role in storing memory....
'.
Function
They, along with the anterior and dorsomedial nuclei in the thalamus, are involved with the processing of recognition memory.They are believed to add the element of smell to memories.
Pathology
Damage to the mammillary bodies due to thiamineThiamine
Thiamine or thiamin or vitamin B1 , named as the "thio-vitamine" is a water-soluble vitamin of the B complex. First named aneurin for the detrimental neurological effects if not present in the diet, it was eventually assigned the generic descriptor name vitamin B1. Its phosphate derivatives are...
deficiency is implied in pathogenesis of Wernicke-Korsakoff syndrome
Wernicke-Korsakoff syndrome
Wernicke–Korsakoff syndrome is a manifestation of thiamine deficiency, or beriberi. This is usually secondary to alcohol abuse...
. Symptoms include impaired memory
Memory
In psychology, memory is an organism's ability to store, retain, and recall information and experiences. Traditional studies of memory began in the fields of philosophy, including techniques of artificially enhancing memory....
, also called anterograde amnesia
Anterograde amnesia
Anterograde amnesia is a loss of the ability to create new memories after the event that caused the amnesia, leading to a partial or complete inability to recall the recent past, while long-term memories from before the event remain intact. This is in contrast to retrograde amnesia, where memories...
, 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
Amnesia
Amnesia is a condition in which one's memory is lost. The causes of amnesia have traditionally been divided into categories. Memory appears to be stored in several parts of the limbic system of the brain, and any condition that interferes with the function of this system can cause amnesia...
syndromes in humans.
External links
- TheFreeDictionary.com - 'Mammillary body'