Medial dorsal nucleus explained

Medial dorsal nucleus should not be confused with Dorsomedial hypothalamic nucleus.

Medial dorsal nucleus
Latin:nucleus mediodorsalis thalami

The medial dorsal nucleus (or mediodorsal nucleus of thalamus, dorsomedial nucleus, dorsal medial nucleus, or medial nucleus group) is a large nucleus in the thalamus.[1] [2] It is separated from the other thalamic nuclei by the internal medullary lamina.

The medial dorsal nucleus is interconnected with the prefrontal cortex, therefore involved in prefrontal functions. Damage to the interconnected tract or the nucleus itself will result in similar damage to the prefrontal cortex.[3] It is also believed to play a role in memory.[4]

Structure

The medial dorsal nucleus relays inputs from the amygdala and olfactory cortex and projects to the prefrontal cortex and the limbic system,[5] [6] 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.[7]

By stereology the number of brain cells in the region has been estimated at around 6.43 million neurons in the adult human brain and 36.3 million glial cells, with the newborn having quite different numbers: around 11.2 million neurons and 10.6 million glial cells.[8]

Parts of nucleus

The medial dorsal nucleus has four parts.[9]

  1. paralaminar part of the medial dorsal nucleus
  2. magnocellular part of the medial dorsal nucleus
  3. parvicellular/parvocellular part of the medial dorsal nucleus
  4. densocellular part of the medial dorsal nucleus

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" processing of the classical or lemniscal system. This pathway activates parts of the brain that evoke emotional responses.

Saccadic efference copy

The medial dorsal 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.[10]

Clinical significance

Damage to the medial dorsal nucleus has been associated with Korsakoff's syndrome.[11]

References

Notes and References

  1. Mitchell AS, Chakraborty S . What does the mediodorsal thalamus do? . Front Syst Neurosci . 7 . 37 . 2013 . 23950738 . 3738868 . 10.3389/fnsys.2013.00037 . free .
  2. Georgescu IA, Popa D, Zagrean L . The Anatomical and Functional Heterogeneity of the Mediodorsal Thalamus . Brain Sci . 10 . 9 . September 2020 . 624 . 32916866 . 7563683 . 10.3390/brainsci10090624 . free .
  3. Book: Vanderah . Todd W. . Nolte's The human brain: an introduction to its functional anatomy . Gould . Douglas J. . Nolte . John . 2016 . Elsevier . 978-1-4557-2859-6 . 7th . Philadelphia, PA . 408–409.
  4. Li XB, Inoue T, Nakagawa S, Koyama T . Effect of mediodorsal thalamic nucleus lesion on contextual fear conditioning in rats . Brain Res. . 1008 . 2 . 261–72 . May 2004 . 15145764 . 10.1016/j.brainres.2004.02.038 . 36284389 .
  5. Book: Hall . John E. . Hall . Michael E. . Guyton and Hall textbook of medical physiology . 2021 . Elsevier . Philadelphia, PA . 978-0-323-59712-8 . 14th . 681–682.
  6. Book: Brodal . Per . The Central Nervous System . Oxford University Press . New York . 2016 . 5th . 978-0-19-022895-8 . 315.
  7. Jacob Jelsing. Anders Hay-Schmidt. Tim Dyrby. Ralf Hemmingsen. Harry B. M. Uylings. Bente Pakkenberg. The prefrontal cortex in the Göttingen minipig brain defined by neural projection criteria and cytoarchitecture. Brain Research Bulletin. 2006. 70. 4 - 6. 322 - 336. 10.1016/j.brainresbull.2006.06.009. 17027768. 38174266.
  8. Maja Abitz . Rune Damgaard Nielsen . Edward G. Jones . Henning Laursen . Niels Graem . Bente Pakkenberg. amp. Excess of Neurons in the Human Newborn Mediodorsal Thalamus Compared with That of the Adult. Cerebral Cortex. 17. 11. 2007. 2573 - 2578. 10.1093/cercor/bhl163 . 17218480 . free .
  9. http://braininfo.rprc.washington.edu/whereisit.aspx?language=0&requestID=ID312&parentID=ID312&originalID=ID312 BrainInfo NeuroName 312 parts
  10. Sommer. Marc A.. Wurtz. Robert H.. 2008. Brain circuits for the internal monitoring of movements. Annual Review of Neuroscience. 31. 317–338. 10.1146/annurev.neuro.31.060407.125627. 0147-006X. 2813694. 18558858.
  11. Kopelman. Michael D.. 2015-07-01. What does a comparison of the alcoholic Korsakoff syndrome and thalamic infarction tell us about thalamic amnesia?. Neuroscience & Biobehavioral Reviews. The Cognitive Thalamus. 54. 46–56. 10.1016/j.neubiorev.2014.08.014. 25218758. 0149-7634. free.

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Medial dorsal nucleus".

Except where otherwise indicated, Everything.Explained.Today is © Copyright 2009-2025, A B Cryer, All Rights Reserved. Cookie policy.