Interpeduncular nucleus

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Interpeduncular nucleus
Details
PartsApical subnucleus (IPA), Central subnucleus (IPC), Dorsolateral subnucleus (IPDL)x2, Dorsomedial subnucleus (IPDM)x2, Intermediate subnucleus (IPI)x2, Lateral subnucleus (IPL)x2, Rostral subnucleus (IPR)
Identifiers
Latin nucleus interpeduncularis
MeSH D066268
NeuroNames 522
NeuroLex ID birnlex_1000
TA98 A14.1.06.313
TA2 5897
FMA 72439
Anatomical terms of neuroanatomy

The interpeduncular nucleus (IPN) is an unpaired, ovoid group of neurons at the base of the midbrain tegmentum. In the midbrain it lies below the interpeduncular fossa. As the name suggests, the interpeduncular nucleus lies in between the cerebral peduncles.

Contents

Composition

The Interpeduncular nucleus is primarily GABAergic and contains at least two neuron clusters of different morphologies. [1] The region is divided into 7 paired and unpaired subnuclei

Subdivisions

The presence of non-homologous subdivisions of the Interpeduncular nucleus was first noticed by Cajal over a hundred years ago. [2] The currently recognized standard subdivision notation was mostly established by Hammill and Lenn in 1984 by combining the work and notations of four groups. [3] Although most of their proposed convention stuck, at some point the proposed "rostral lateral" sub-nucleus was renamed "dorsomedial" and became immortalized in brain atlases.

Unpaired sub-nucleus. Former names include: "caudal dorsal", "dorsal", and "pars dorsalis magnocellularis". [3]

Unpaired sub-nucleus. Former names include: "rostral ventral", "caudal central", "posterior inter", and "pars medianus". [3]

Paired sub-nucleus.

Paired sub-nucleus. Former names include: "rostral lateral" and "interstitial". [3]

Paired sub-nucleus. Former names include: "caudal intermediate", "posterior inner" and "pars medianus". [3]

Paired sub-nucleus. Former names include: "caudal lateral", "paramedian" and "pars lateralis". [3]

Unpaired sub-nucleus. Former names include: "central" and "pars dorsalis". [3]

Inputs

The major input to the IPN arrives via the fasciculus retroflex from the medial habenula. This pathway presents the IPN with several excitatory neurotransmitters including ACh and Substance P. Other brain regions that project to the Interpeduncular nucleus include: the Nucleus of diagonal band, the dorsal Tegmentum, the Raphe nuclei, the Central grey, and the Locus coeruleus. [4]

Outputs

The major output pathways are inhibitory and project to the dorsal Tegmental area, the Periaqueductal gray and also the Raphe nuclei. In addition, output is sent to the following: the mediodorsal nucleus of the Thalamus, the lateral Habenula, the Septal nuclei, the anterior Mammillary nuclei, the Nucleus of diagonal band, the Preoptic area, the Ventral tegmental area, and in some species the dorsal and/or lateral Hypothalamus. [4]

Function

The Interpeduncular nucleus is thought to have a broad inhibitory effects on many other brain regions. IPN activity is linked with decreased dopamine release and utilization from dopamine producing regions. [5] The Interpeduncular nucleus is implicated with a role in the regulation of Rapid eye movement sleep. [6] Activation of the GAD2 expressing sub-population of the IPN produced the physical symptoms of nicotine withdrawal suggesting that the misfunction of this region may be an active component of withdrawal. [7]

See also

Related Research Articles

<span class="mw-page-title-main">Basal ganglia</span> Group of subcortical nuclei involved in the motor and reward systems

The basal ganglia (BG) or basal nuclei are a group of subcortical nuclei found in the brains of vertebrates. In humans and other primates, differences exist, primarily in the division of the globus pallidus into external and internal regions, and in the division of the striatum. Positioned at the base of the forebrain and the top of the midbrain, they have strong connections with the cerebral cortex, thalamus, brainstem and other brain areas. The basal ganglia are associated with a variety of functions, including regulating voluntary motor movements, procedural learning, habit formation, conditional learning, eye movements, cognition, and emotion.

<span class="mw-page-title-main">Brainstem</span> Posterior part of the brain, adjoining and structurally continuous

The brainstem is the posterior stalk-like part of the brain that connects the cerebrum with the spinal cord. In the human brain the brainstem is composed of the midbrain, the pons, and the medulla oblongata. The midbrain is continuous with the thalamus of the diencephalon through the tentorial notch, and sometimes the diencephalon is included in the brainstem.

<span class="mw-page-title-main">Midbrain</span> Forward-most portion of the brainstem

The midbrain or mesencephalon is the uppermost portion of the brainstem connecting the diencephalon and cerebrum with the pons. It consists of the cerebral peduncles, tegmentum, and tectum.

<span class="mw-page-title-main">Raphe nuclei</span> Moderate-size cluster of nuclei found in brain stem

The raphe nuclei are a moderate-size cluster of nuclei found in the brain stem. They have 5-HT1 receptors which are coupled with Gi/Go-protein-inhibiting adenyl cyclase. They function as autoreceptors in the brain and decrease the release of serotonin. The anxiolytic drug Buspirone acts as partial agonist against these receptors. Selective serotonin reuptake inhibitor (SSRI) antidepressants are believed to act in these nuclei, as well as at their targets.

<span class="mw-page-title-main">Ventral tegmental area</span> Group of neurons on the floor of the midbrain

The ventral tegmental area (VTA), also known as the ventral tegmental area of Tsai, or simply ventral tegmentum, is a group of neurons located close to the midline on the floor of the midbrain. The VTA is the origin of the dopaminergic cell bodies of the mesocorticolimbic dopamine system and other dopamine pathways; it is widely implicated in the drug and natural reward circuitry of the brain. The VTA plays an important role in a number of processes, including reward cognition and orgasm, among others, as well as several psychiatric disorders. Neurons in the VTA project to numerous areas of the brain, ranging from the prefrontal cortex to the caudal brainstem and several regions in between.

<span class="mw-page-title-main">Periaqueductal gray</span> Nucleus surrounding the cerebral aqueduct

The periaqueductal gray (PAG), also known as the central gray, is a brain region that plays a critical role in autonomic function, motivated behavior and behavioural responses to threatening stimuli. PAG is also the primary control center for descending pain modulation. It has enkephalin-producing cells that suppress pain.

<span class="mw-page-title-main">Reticular formation</span> Spinal trigeminal nucleus

The reticular formation is a set of interconnected nuclei in the brainstem that spans from the lower end of the medulla oblongata to the upper end of the midbrain. The neurons of the reticular formation make up a complex set of neural networks in the core of the brainstem. The reticular formation is made up of a diffuse net-like formation of reticular nuclei which is not well-defined. It may be seen as being made up of all the interspersed cells in the brainstem between the more compact and named structures.

<span class="mw-page-title-main">Pontine tegmentum</span>

The pontine tegmentum, or dorsal pons, is the dorsal part of the pons located within the brainstem. The ventral part or ventral pons is known as the basilar part of the pons, or basilar pons. Along with the dorsal surface of the medulla oblongata, it forms part of the rhomboid fossa – the floor of the fourth ventricle.

<span class="mw-page-title-main">Habenula</span> Small bilateral neuronal structure in the brain of vertebrates

The habenula is a small bilateral neuronal structure in the brain of vertebrates, that has also been called a microstructure since it is no bigger than a pea. The naming as little rein describes its elongated shape in the epithalamus, where it borders the third ventricle, and lies in front of the pineal gland.

The zona incerta (ZI) is a horizontally elongated small nucleus that separates the larger subthalamic nucleus from the thalamus. Its connections project extensively over the brain from the cerebral cortex down into the spinal cord.

<span class="mw-page-title-main">Tegmentum</span> Part of the brain stem

The tegmentum is a general area within the brainstem. The tegmentum is the ventral part of the midbrain and the tectum is the dorsal part of the midbrain. It is located between the ventricular system and distinctive basal or ventral structures at each level. It forms the floor of the midbrain (mesencephalon) whereas the tectum forms the ceiling. It is a multisynaptic network of neurons that is involved in many subconscious homeostatic and reflexive pathways. It is a motor center that relays inhibitory signals to the thalamus and basal nuclei preventing unwanted body movement.

<span class="mw-page-title-main">Dorsal raphe nucleus</span>

The dorsal raphe nucleus is one of the raphe nuclei. It is situated in the brainstem at the midline. It has rostral and caudal subdivisions:

<span class="mw-page-title-main">Median raphe nucleus</span> Brain region having polygonal, fusiform, piriform neurons

The median raphe nucleus(MRN), also known as the superior central nucleus, is a nucleus in the brainstem composed of polygonal, fusiform, and piriform neurons, which exists rostral to the pontine raphe nucleus. The median raphe nucleus is one of several raphe nuclei that lies on the brainstem midline. It is one of two nuclei that are situated more superior to the others. The second of these nuclei is the dorsal raphe nucleus (DRN). The MRN extends from the lower part of the dorsal raphe nucleus to an approximate position at the decussation of the superior cerebellar peduncle.

Dopaminergic cell groups, DA cell groups, or dopaminergic nuclei are collections of neurons in the central nervous system that synthesize the neurotransmitter dopamine. In the 1960s, dopaminergic neurons or dopamine neurons were first identified and named by Annica Dahlström and Kjell Fuxe, who used histochemical fluorescence. The subsequent discovery of genes encoding enzymes that synthesize dopamine, and transporters that incorporate dopamine into synaptic vesicles or reclaim it after synaptic release, enabled scientists to identify dopaminergic neurons by labeling gene or protein expression that is specific to these neurons.

Serotonergic cell groups refer to collections of neurons in the central nervous system that have been demonstrated by histochemical fluorescence to contain the neurotransmitter serotonin (5-hydroxytryptamine). Since they are for the most part localized to classical brainstem nuclei, particularly the raphe nuclei, they are more often referred to by the names of those nuclei than by the B1-9 nomenclature. These cells appear to be common across most mammals and have two main regions in which they develop; one forms in the mesencephlon and the rostral pons and the other in the medulla oblongata and the caudal pons.

The rostromedial tegmental nucleus (RMTg), also known as the tail of the ventral tegmental area (tVTA), is a GABAergic nucleus which functions as a "master brake" for the midbrain dopamine system. This region was discovered by the researchers, M. Barrot, J.Kaufling and T. Jhou. It is poorly differentiated from the rest of the ventral tegmental area (VTA) and possesses robust functional and structural links to the dopamine pathways. Notably, both acute and chronic exposure to psychostimulants have been shown to induce FosB and ΔFosB expression in the RMTg; no other drug type has been shown to induce these proteins in the RMTg.

The parafacial zone (PZ) is a brain structure located in the brainstem within the medulla oblongata believed to be heavily responsible for non-rapid eye movement (non-REM) sleep regulation, specifically for inducing slow-wave sleep.

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

The fasciculus retroflexus (FR) also known as the habenulointerpeduncular tract is a bundle of fibers located at the base of the midbrain in vertebrates. Connected to the habenula (Hbn) and the interpeduncular nucleus (IPN), the fasciculus retroflexus is involved in a variety of bodily phenomena, some being sleep retention. and drug addiction. It acts as a channel through which messages are sent between the stria medullaris and the mid- and hindbrain. The fasciculus retroflexus, along with the stria medullaris, the habenula, and the medial forebrain bundle forms a unit for the transfer of neurological impulses. In this unit, the fasciculus retroflexus mediates the transfer of information for processes such as pain, pleasure, and motor control

References

  1. Gioia, Magda (1994), "A cluster analysis of the neurons of the rat interpeduncular nucleus", Journal of Anatomy, 185 ( Pt 3), University of Milan, Italy: Wiley-Blackwell: 459–464, PMC   1166650 , PMID   7649781
  2. Ramón y Cajal, Santiago (1909). Histologie du Système Nerveux de l'Homme et des Vertébrés, L. Azoulay, trans. Paris: Maloine. Translated into English as Histology of the Nervous System of Man and Vertebrates (1995). New York: Oxford University Press.
  3. 1 2 3 4 5 6 7 Lenn, NJ; Hamill, GS (July 1984). "Subdivisions of the interpeduncular nucleus: a proposed nomenclature". Brain Research Bulletin. 13 (1): 203–4. doi:10.1016/0361-9230(84)90023-6. PMID   6478267.
  4. 1 2 Morley, BJ (1986). "The interpeduncular nucleus". International Review of Neurobiology. 28: 157–82. doi:10.1016/s0074-7742(08)60108-7. ISBN   9780123668288. PMID   2433243.
  5. Nishikawa, T; Fage, D; Scatton, B (May 14, 1986). "Evidence for, and nature of, the tonic inhibitory influence of habenulointerpeduncular pathways upon cerebral dopaminergic transmission in the rat". Brain Research. 373 (1–2): 324–36. doi:10.1016/0006-8993(86)90347-1. PMID   2424555.
  6. Funato, Hiromasa (2010), Loss of Goosecoid-like and DiGeorge syndrome critical region 14 in interpeduncular nucleus results in altered regulation of rapid eye movement sleep, University of Texas Southwestern Medical Center, Dallas: PNAS
  7. Zhao-Shea, R; Liu, L; Pang, X; Gardner, PD; Tapper, AR (Nov 13, 2013). "Activation of GABAergic Neurons in the Interpeduncular Nucleus Triggers Physical Nicotine Withdrawal Symptoms". Current Biology. 23 (23): 2327–35. doi:10.1016/j.cub.2013.09.041. PMC   3855889 . PMID   24239118.