The medial dorsal nucleus (or dorsomedial nucleus of thalamus) is a large
nucleus
Nucleus ( : nuclei) is a Latin word for the seed inside a fruit. It most often refers to:
*Atomic nucleus, the very dense central region of an atom
*Cell nucleus, a central organelle of a eukaryotic cell, containing most of the cell's DNA
Nucle ...
in the
thalamus.
It is believed to play a role in
memory.
Structure
It relays inputs from the amygdala and olfactory cortex and projects to the
prefrontal cortex and the
limbic system
The limbic system, also known as the paleomammalian cortex, is a set of brain structures located on both sides of the thalamus, immediately beneath the medial temporal lobe of the cerebrum primarily in the forebrain.Schacter, Daniel L. 2012. ''Ps ...
and in turn relays them to the prefrontal
association cortex
The cerebral cortex, also known as the cerebral mantle, is the outer layer of neural tissue of the cerebrum of the brain in humans and other mammals. The cerebral cortex mostly consists of the six-layered neocortex, with just 10% consisting of ...
. As a result, it plays a crucial role in attention, planning, organization, abstract thinking, multi-tasking, and active memory.
The connections of the medial dorsal nucleus have even been used to delineate the prefrontal cortex of the
Göttingen minipig
The Göttingen minipig (also known as the ''Göttinger'' or "Goettingen" minipig) is a breed of small swine. The Göttingen minipig is the smallest domestic pig breed known in the world; as an adult, they weigh around . Beside being known for the ...
brain.
By
stereology the number of
brain cells in the region has been estimated to around 6.43 million
neurons in the adult human brain and 36.3 million
glial cells, and with the newborn having quite different numbers: around 11.2 million neurons and 10.6 million glial cells.
Function
Pain processing
While both the ventral and medial dorsal nuclei process pain, the medial dorsal nucleus bypasses primary cortices, sending their axons directly to secondary and association cortices. The cells also send axons directly to many parts of the brain, including nuclei of the limbic system such as the lateral nucleus of the amygdala, the anterior cingulate, and the hippocampus. This part of the sensory system, known as the non-classical or
extralemniscal system is less accurate, and less detailed in regards to sensory signal analysis. This processing is known colloquially as "fast and dirty" rather than the "slow and accurate" system of classical or lemniscal system. This pathway activates parts of the brain that evoke emotional responses.
Saccadic efference copy
This nucleus is also presumed to play a role in monitoring internal movements of the eye. Specifically, its function is to relay the information about how the eyes will be moved (efference copy, also known as corollary discharge) from the superior colliculus to the frontal eye fields (FEF) in order to aid the neurons in FEF to change their receptive fields to where the visual stimuli will appear after the saccade.
Clinical significance
Damage to the medial dorsal nucleus has been associated with
Korsakoff's syndrome
Korsakoff syndrome (KS) is a disorder of the central nervous system characterized by amnesia, deficits in explicit memory, and confabulation. This neurological disorder is caused by a deficiency of thiamine (vitamin B1) in the brain, and it is ...
.
Additional images
File:Constudthal.gif, Thalamus
File:Territoriostalamo.svg, Thalamus
References
* Aage R. Moller "Pain: Its anatomy, physiology and treatment" 2012
External links
*
{{DEFAULTSORT:Medial Dorsal Nucleus
Thalamic nuclei