Medial dorsal nucleus

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Medial dorsal nucleus
ThalamicNuclei.svg
Thalamic nuclei: (left thalamus from left)
MNG = Midline nuclear group
AN = Anterior nuclear group
MD = Medial dorsal nucleus
VNG = Ventral nuclear group
VA = Ventral anterior nucleus
VL = Ventral lateral nucleus
VPL = Ventral posterolateral nucleus
VPM = Ventral posteromedial nucleus
LNG = Lateral nuclear group
PUL = Pulvinar
MTh = Metathalamus
LG = Lateral geniculate nucleus
MG = Medial geniculate nucleus
Thalmus.png
right thalamus nuclei (above right view)
Details
Identifiers
Latin nucleus mediodorsalis thalami
MeSH D020645
NeuroNames 312
NeuroLex ID birnlex_1543
TA98 A14.1.08.622
TA2 5681
FMA 62156
Anatomical terms of neuroanatomy

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.

Contents

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.[ citation needed ]

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.[ citation needed ]

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]

Additional images

References

  1. ↑ Mitchell AS, Chakraborty S (2013). "What does the mediodorsal thalamus do?". Front Syst Neurosci. 7: 37. doi: 10.3389/fnsys.2013.00037 . PMC   3738868 . PMID   23950738.
  2. ↑ Georgescu IA, Popa D, Zagrean L (September 2020). "The Anatomical and Functional Heterogeneity of the Mediodorsal Thalamus". Brain Sci. 10 (9): 624. doi: 10.3390/brainsci10090624 . PMC   7563683 . PMID   32916866.
  3. ↑ Vanderah, Todd W.; Gould, Douglas J.; Nolte, John (2016). Nolte's The human brain: an introduction to its functional anatomy (7th ed.). Philadelphia, PA: Elsevier. pp. 408–409. ISBN   978-1-4557-2859-6.
  4. ↑ Li XB, Inoue T, Nakagawa S, Koyama T (May 2004). "Effect of mediodorsal thalamic nucleus lesion on contextual fear conditioning in rats". Brain Res. 1008 (2): 261–72. doi:10.1016/j.brainres.2004.02.038. PMID   15145764. S2CID   36284389.
  5. ↑ Hall, Michael E.; Hall, John E. (2021). Guyton and Hall textbook of medical physiology (14th ed.). Philadelphia, PA: Elsevier. pp. 681–682. ISBN   978-0-323-59712-8.
  6. ↑ Brodal, Per (2016). The Central Nervous System (5th ed.). New York: Oxford University Press. p. 315. ISBN   978-0-19-022895-8.
  7. ↑ Jacob Jelsing; Anders Hay-Schmidt; Tim Dyrby; Ralf Hemmingsen; Harry B. M. Uylings; Bente Pakkenberg (2006). "The prefrontal cortex in the Göttingen minipig brain defined by neural projection criteria and cytoarchitecture". Brain Research Bulletin . 70 (4–6): 322–336. doi:10.1016/j.brainresbull.2006.06.009. PMID   17027768. S2CID   38174266.
  8. ↑ Maja Abitz; Rune Damgaard Nielsen; Edward G. Jones; Henning Laursen; Niels Graem & Bente Pakkenberg (2007). "Excess of Neurons in the Human Newborn Mediodorsal Thalamus Compared with That of the Adult". Cerebral Cortex . 17 (11): 2573–2578. doi: 10.1093/cercor/bhl163 . PMID   17218480.
  9. ↑ 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. doi:10.1146/annurev.neuro.31.060407.125627. ISSN   0147-006X. PMC   2813694 . PMID   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?" (PDF). Neuroscience & Biobehavioral Reviews. The Cognitive Thalamus. 54: 46–56. doi: 10.1016/j.neubiorev.2014.08.014 . ISSN   0149-7634. PMID   25218758.
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