Dorsal tegmental nucleus

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The dorsal tegmental nucleus (DTN), also known as dorsal tegmental nucleus of Gudden (DTg), is a group of neurons located in the brain stem, which are involved in spatial navigation and orientation.

Contents

Anatomy

The dorsal tegmental nucleus is located in the brain stem near the midline. Two nuclei exist in both hemispheres. The DTN is generally subdivided into four parts called partes centralis, ventromedialis, anterior, and posterior. [1]

DTN contains a dense population of GABAergic cells. [2] [3] In the rat, few also express calbindin (CB) or calretinin (CR). Many of the DTN GABAergic cells do express parvalbumin (PV) with the densest expression in the pars ventralis portion. [4] [5] DTN neurons in rats contain small number of neuropeptide Y positive (NPY) neurons implicating a role in hunger and feeding. In rats, the DTN contains a small number of enkephalin, substance p, and glutamatergic neurons which project to mammillary. [6]

Circuitry

As part of the Papez circuit, the DTN receives input from habenula neurons [1] and lateral mammillary neurons. [7] DTN especially the central part of the DTN receives projections from the G-protein coupled receptor GPR151 containing habenula neurons. [8]

The pars centralis of the DTN receives input from the prepositus hypoglossi and the supragenualis nucleus. [9] Pars ventromedialis of the DTN receives inputs from

Projections

Dorsal tegmental fibres project to

DTN is a major source of fibers in the mammillary peduncle. Rostral DTN cells that project to the LMN are localized within pars dorsalis and caudal cells that project to the LMN are located in the pars ventralis.

Function

This nucleus is involved in landmark and directional navigation. [12] Subpopulations of DTN neurons respond differently to changes in angular head velocity (AHV) and head direction (HD). [13] [14] [15] [16] Some cells respond to changes in head movement in specific directions such as to the left, right, or both. The firing activity of these cells are also affected by the speed of the movement of the head as well. DTN lesions permanently impaired landmark navigation, but only transiently impaired directional navigation.


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<span class="mw-page-title-main">Hippocampus anatomy</span>

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<span class="mw-page-title-main">HSD2 neuron</span>

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References

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  6. ↑ Gonzalo-Ruiz A, Romero JC, Sanz JM, Morte L (1999). "Localization of amino acids, neuropeptides and cholinergic neurotransmitter markers in identified projections from the mesencephalic tegmentum to the mammillary nuclei of the rat". J Chem Neuroanat. 16 (2): 117–33. doi:10.1016/s0891-0618(98)00063-5. PMID   10223311. S2CID   916774.
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  10. ↑ Faiers AA, Mogenson GJ (1976). "Electrophysiological identification of neurons in locus coeruleus". Exp Neurol. 53 (1): 254–66. doi:10.1016/0014-4886(76)90295-8. PMID   964341. S2CID   35982595.
  11. ↑ MOREST DK (1961). "Connexions of the dorsal tegmental nucleus in rat and rabbit". J Anat. 95 (Pt 2): 229–46. PMC   1244467 . PMID   13772534.
  12. ↑ Clark BJ, Rice JP, Akers KG, Candelaria-Cook FT, Taube JS, Hamilton DA (2013). "Lesions of the dorsal tegmental nuclei disrupt control of navigation by distal landmarks in cued, directional, and place variants of the Morris water task". Behav Neurosci. 127 (4): 566–81. doi:10.1037/a0033087. PMC   3997071 . PMID   23731069.
  13. ↑ Bassett JP, Taube JS (2001). "Neural correlates for angular head velocity in the rat dorsal tegmental nucleus". J Neurosci. 21 (15): 5740–51. doi: 10.1523/jneurosci.21-15-05740.2001 . PMC   6762668 . PMID   11466446.
  14. ↑ Sharp PE, Tinkelman A, Cho J (2001). "Angular velocity and head direction signals recorded from the dorsal tegmental nucleus of gudden in the rat: implications for path integration in the head direction cell circuit". Behav Neurosci. 115 (3): 571–88. doi:10.1037/0735-7044.115.3.571. PMID   11439447.
  15. ↑ Taube JS (2007). "The head direction signal: origins and sensory-motor integration". Annu Rev Neurosci. 30: 181–207. doi:10.1146/annurev.neuro.29.051605.112854. PMID   17341158.
  16. ↑ Bassett JP, Tullman ML, Taube JS (2007). "Lesions of the tegmentomammillary circuit in the head direction system disrupt the head direction signal in the anterior thalamus". J Neurosci. 27 (28): 7564–77. doi: 10.1523/JNEUROSCI.0268-07.2007 . PMC   6672597 . PMID   17626218.
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