This article is in need of attention from a psychologist/academic expert on the subject. Please help recruit one, or improve this page yourself if you are qualified. This banner appears on articles that are weak and whose contents should be approached with academic caution. Brain: Raphe nuclei Section of the medulla oblongata at about the middle of the olive. (Raphe nuclei not labeled, but 'raphe' labeled at left.) [[Image:|250px|center|]] Latin nuclei raphes Gray's subject # Part of Components Artery Vein BrainInfo/UW - MeSH A08.186.211.132.659.632 The raphe nuclei (Latin: raphe = 'seam'; nuclei = cell 'clusters'; pronounced RAY-fee) are a moderate-size cluster of nuclei found in the pons part of the hindbrain portion of the brain stem. Their main function is to release serotonin to the rest of the brain. Selective serotonin reuptake inhibitor (SSRI) antidepressants are believed to act in these nuclei, as well as at their targets. Contents 1 Anatomy 2 Projections 3 Function 4 Further reading 5 Additional images 6 See also 7 References 8 Extenal links Anatomy The raphe nuclei are traditionally considered to be the medial portion of the reticular formation, and they appear as a ridge of cells in the center and most medial portion of the brain stem. In order from caudal to rostral, the raphe nuclei are known as the nucleus raphe obscurus, the raphe magnus, the raphe pontis, the raphe pallidus, the nucleus centralis superior, nucleus raphe dorsalis, nuclei linearis intermedius and linearis rostralis. Some scientists chose to group the linearis nuclei into one nucleus, shrinking the number of raphe to seven, e.g., NeuroNames makes the following ordering: Raphe nuclei of medulla Nucleus raphe obscurus (nucleus raphe obscurus) Nucleus raphe magnus (raphe magnus) Nucleus pallidus (raphe pallidus) Raphe nuclei of the pontine reticular formation Pontine raphe nucleus (raphe pontis) Inferior central nucleus Raphe nuclei of the midbrain reticular formation Superior central nucleus (nucleus centralis superior) Dorsal raphe nucleus (nucleus raphe dorsalis) Projections All of these nuclei have fascinating interactions with almost every pertinent portion of the brain, but only a few of them have specifically independent interaction worth exploring in their own right. These select nuclei are discussed as follows. Overall, the caudal raphe nuclei, including the raphe magnus, pallidus and raphe obscurus, all project towards the spinal cord and brain stem. The more-rostral nuclei, including the raphe pontis, centralis (also called median), dorsal, tend to project towards the brain areas of higher function. The 7 raphe nuclei receive afferent connections from some of the most fascinating spots in the brain, only to project back to them and alter their processes. Function The raphe nuclei have a vast impact upon the central nervous system. The raphe nuclei can be of particular interest to neurologists and psychologists since many of the neurons in the nuclei (but not the majority) are serotonergic, i.e., contain serotonin - a type of monoamine neurotransmitter. Serotonin, also called 5-HT, seems to be the culprit in many of our modern psycho-pharmaceutical problems, such as anorexia, depression, and sleep disorders. It is not the sole culprit in the aforementioned disorders, but it is the area that the pharmacologists know how to affect in the best manner. It is important to note that pharmacology traditionally affects global serotonin levels, while the actions of the raphe nuclei are dependent on the complex interplay between nuclei. Projections from the raphe nuclei also terminate in the dorsal horn of spinal gray matter where they regulate the release of enkephalins, which inhibit pain sensation. Further reading Currie, David (2005). A Lecture, Higher Brain Function: Activation of the Brain and Levels of Consciousness. East Tennessee State University. Sari, Youssef (October 2004). Serotonin1B receptors: from protein to physiological function and behavior. Neuroscience & Biobehavioral Reviews 28 (6): 565–582. Additional images Dopamineseratonin.gif Dopamine and serotonin See also List of regions in the human brain Limbic system Locus ceruleus Reticular formation Substantia nigra Pedunculopontine nucleus References ↑ (1999) "Understanding the neuroanatomical organization of serotonergic cells in brain provides insight into the functions of this neurotransmitter" George J. Siegel Basic Neurochemistry, Bernard W. Agranoff, Stephen K. Fisher, R. Wayne Albers, Michael D. Uhler, Sixth, Lippincott Williams and Wilkins. ISBN 0-397-51820-X. "In 1964, Dahlstrom and Fuxe (discussed in ), using the Falck-Hillarp technique of histofluorescence, observed that the majority of serotonergic soma are found in cell body groups, which previously had been designated as the raphe nuclei." ↑ Briley, M (October 1993). Neurobiological mechanisms involved in antidepressant therapies. Clin Neuropharmacol 16 (5): 387–400. ↑ (1998). Fig. 5. The midsagittal section of the brain stem indicating the position of the raphe nuclei. (GIF) ↑ BrainInfo at the University of Washington ancil-190 ↑ BilZ0r, Erowid (2005). Figure 4. Diagram of the human brain showing the divergent serotonergic projections of the raphe nuclei to both cortical and subcortical locations throughout the brain.. (PNG) The Neuropharmacology of Hallucinogens: a technical overview. Erowid Pharmacology Vaults. Extenal links [Nextbio v·d·e Brain: rhombencephalon (hindbrain) Metencephalon/ pons Dorsal/ (tegmentum) surface: Locus ceruleus Trigeminal lemniscus (Dorsal trigeminal tract, Ventral trigeminal tract) cranial nuclei: GSA: Principal V/Spinal V - VIII-c (Dorsal, Anterior)/VIII-v (Lateral, Superior, Medial, Inferior) - SVE: Motor V - VII - GSE: VI - GVE: VII: Superior salivary nucleus MLF, III, IV and VI (vestibulo-oculomotor fibers, medial vestibulospinal tract) sensory/ascending: Trapezoid body/VIII - Superior olivary nucleus Inferior cerebellar peduncle (Vestibulocerebellar tract) motor/descending: Apneustic center • Pneumotaxic center (Medial parabrachial nucleus) - Lateral parabrachial nucleus Ventral/ (base) Middle cerebellar peduncles (Pontocerebellar fibers) - Pontine nuclei motor/descending: Corticospinal tract - Corticobulbar tract - Corticopontine fibers Raphe/reticular Reticular formation (Caudal, Oral, Tegmental, Paramedian) • Raphe nuclei (Median) Myelencephalon/ medulla Dorsal surface: Posterior median sulcus - Postero-lateral sulcus - Area postrema cranial nuclei: GVA: VII,IX,X: Solitary/tract • SVA: Gustatory nucleus • GSE: XII • GVE: IX,X,XI: Ambiguus • SVE: X: Dorsal • IX: Inferior salivatory nucleus - MLF, III, IV and VI sensory/ascending: Gracile nucleus • Cuneate nucleus (Accessory cuneate nucleus) • Sensory decussation • Medial lemniscus motor/descending: Dorsal respiratory group Ventral motor/descending: Ventral respiratory group - Pyramid (Motor decussation) - Inferior olivary nucleus (Olivocerebellar tract, Rubro-olivary tract) surface: Anterior median fissure - Antero-lateral sulcus - Arcuate nucleus of medulla - Olivary body Raphe/reticular Reticular formation (Gigantocellular, Parvocellular, Ventral, Lateral, Paramedian) • Raphe nuclei (Obscurus, Magnus, Pallidus) This page uses Creative Commons Licensed content from Wikipedia (view authors).
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