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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.

（應該是在方向選擇方面。想象這樣的畫面，在密林中，抬起頭環(huán)顧四周，選擇一個能夠到達目的地的方向，或者漫游在叢林中，選擇一個喜歡的、食物可能出現(xiàn)的方向。在這個過程中，我感受到了DA system的活動，所以我認為dorsal tegmental nucleus?與ventral tegmental area有密切聯(lián)系，這種dorsal tegmental nucleus?主導下的方向選擇是一個激發(fā)DA system的途徑。）

Contents

·?1Anatomy

·?1.1Circuitry

·?1.2Projections

·?2Function

·?3References

Anatomy[edit]

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[edit]

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

·?the septal nuclei,

·?diagonal band of Broca,

·?preoptic area,

·?anterior and lateral hypothalamus,

·?lateral and medial habenular nuclei,

·?medial mammillary nucleus and

·?brainstem reticular formation?[9]

Projections[edit]

Dorsal tegmental fibres project to

·?lateral mammillary neurons (LMN)?[4]?[2]?[3]?[5]

·?dorsal noradrenergic bundle?[10]

·?nuclei medialis profundus

·?centralis superior,

·?the tegmental reticular nucleus,

·?the ventral tegmental area of Tsai,?and

·?the posterior hypothalamic nucleus. The nucleus is a major synaptic station for the pathways of the dorsal longitudinal fasciculus between the diencephalon and lower brain stem?[11]

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[edit]

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.

（Dorsal tegmental nucleus與很多重要的結(jié)構(gòu)有連接關系，但是詞條中在結(jié)構(gòu)方面的記載很少，很不詳細，說明現(xiàn)在對它了解不多。在功能方面，明確指出與spatial navigation and orientation有關，這樣一來我能通過自身的經(jīng)歷明確感受到Dorsal tegmental nucleus起作用時的效果，尤其是發(fā)現(xiàn)它與ventral tegmental area有密切關系，在方向選擇過程中我感受到了快感，在漫游移動狀態(tài)下（比如老虎在領地中漫游），必然是通過Dorsal tegmental nucleus選擇方向（既然是漫游，就沒有明確的目的地），走動的過程中必然是快樂無憂的一種狀態(tài)，這樣的話就將Dorsal tegmental nucleus與DA system聯(lián)系在一起了。除此之外，我對它的研究成果就基本沒有了，不過我覺得這是個重要結(jié)構(gòu)。）