The medial dorsal nucleus (or dorsomedial nucleus of thalamus) is a large nucleus in the

thalamus The thalamus (from Greek θάλαμος, "chamber") is a large mass of gray matter located in the dorsal part of the diencephalon (a division of the forebrain). Nerve fibers project out of the thalamus to the cerebral cortex in all directions, ...

. It is believed to play a role in

memory Memory is the faculty of the mind by which data or information is encoded, stored, and retrieved when needed. It is the retention of information over time for the purpose of influencing future action. If past events could not be remembered ...

Structure

It relays inputs from the amygdala and olfactory cortex and projects to the

prefrontal cortex In mammalian brain anatomy, the prefrontal cortex (PFC) covers the front part of the frontal lobe of the cerebral cortex. The PFC contains the Brodmann areas BA8, BA9, BA10, BA11, BA12, BA13, BA14, BA24, BA25, BA32, BA44, BA45, BA46 ...

and the limbic system and in turn relays them to the prefrontal association cortex. 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 brain. By

stereology Stereology is the three-dimensional interpretation of two-dimensional cross sections of materials or tissues. It provides practical techniques for extracting quantitative information about a three-dimensional material from measurements made on two ...

the number of

brain cell Brain cells make up the functional tissue of the brain. The rest of the brain tissue is structural or connective called the stroma which includes blood vessels. The two main types of cells in the brain are neurons, also known as nerve cells, an ...

s in the region has been estimated to around 6.43 million

neuron A neuron, neurone, or nerve cell is an electrically excitable cell that communicates with other cells via specialized connections called synapses. The neuron is the main component of nervous tissue in all animals except sponges and placozoa. ...

s in the adult human brain and 36.3 million

glial cell Glia, also called glial cells (gliocytes) or neuroglia, are non-neuronal cells in the central nervous system (brain and spinal cord) and the peripheral nervous system that do not produce electrical impulses. They maintain homeostasis, form myel ...

s, 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.

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