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• Oliva I, Wanat MJ. Ventral Tegmental Area Afferents and Drug-Dependent Behaviors. Front Psychiatry. 2016;7:30. [PMC free article] [
PubMed]
• 2.
• Samineni VK, Premkumar LS, Faingold CL. Neuropathic pain-induced enhancement of spontaneous and pain-evoked neuronal
activity in the periaqueductal gray that is attenuated by gabapentin. Pain. 2017 Jul;158(7):1241-1253. [PMC free article] [PubMed]
• 3.
• Zelenin PV, Beloozerova IN, Sirota MG, Orlovsky GN, Deliagina TG. Activity of red nucleus neurons in the cat during postural
corrections. J Neurosci. 2010 Oct 27;30(43):14533-42. [PMC free article] [PubMed]
• 4.
• Mather M, Harley CW. The Locus Coeruleus: Essential for Maintaining Cognitive Function and the Aging Brain. Trends Cogn Sci. 2016
Mar;20(3):214-226. [PMC free article] [PubMed]
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• Dutschmann M, Dick TE. Pontine mechanisms of respiratory control. Compr Physiol. 2012 Oct;2(4):2443-69. [PMC free article] [
PubMed]
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• Angeles Fernández-Gil M, Palacios-Bote R, Leo-Barahona M, Mora-Encinas JP. Anatomy of the brainstem: a gaze into the stem of life.
Semin Ultrasound CT MR. 2010 Jun;31(3):196-219. [PubMed]
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• Brown RE, Basheer R, McKenna JT, Strecker RE, McCarley RW. Control of sleep and wakefulness. Physiol Rev. 2012 Jul;92(3):1087-187.
[PMC free article] [PubMed]
• 8.
• Javed K, Reddy V, Lui F. StatPearls [Internet]. StatPearls Publishing; Treasure Island (FL): Jul 24, 2023. Neuroanatomy, Lateral
Corticospinal Tract. [PubMed]](https://image.slidesharecdn.com/brainstem-250725070339-15b96b58/85/Brain_stem_Medulla-oblongata_functions-of-pons_mid-brain-14-320.jpg)
![• 9.
• Al-Chalabi M, Reddy V, Gupta S. StatPearls [Internet]. StatPearls Publishing; Treasure Island (FL): Aug 14, 2023.
Neuroanatomy, Spinothalamic Tract. [PubMed]
• 10.
• Navarro-Orozco D, Bollu PC. StatPearls [Internet]. StatPearls Publishing; Treasure Island (FL): Aug 7, 2023.
Neuroanatomy, Medial Lemniscus (Reils Band, Reils Ribbon) [PubMed]
• 11.
• Saldaña E, Aparicio MA, Fuentes-Santamaría V, Berrebi AS. Connections of the superior paraolivary nucleus of the rat:
projections to the inferior colliculus. Neuroscience. 2009 Sep 29;163(1):372-87. [PMC free article] [PubMed]
• 12.
• Bressan M, Davis P, Timmer J, Herzlinger D, Mikawa T. Notochord-derived BMP antagonists inhibit endothelial cell
generation and network formation. Dev Biol. 2009 Feb 01;326(1):101-11. [PMC free article] [PubMed]
• 13.
• Dupont G, Schmidt C, Yilmaz E, Oskouian RJ, Macchi V, de Caro R, Tubbs RS. Our current understanding of the
lymphatics of the brain and spinal cord. Clin Anat. 2019 Jan;32(1):117-121. [PubMed]
• 14.
• Lipovsek M, Wingate RJ. Conserved and divergent development of brainstem vestibular and auditory nuclei. Elife. 2018
Dec 19;7 [PMC free article] [PubMed]
• 15.
• Tortora F, Caranci F, Belfiore MP, Manzi F, Pagliano P, Cirillo S. Brainstem variant of posterior reversible
encephalopathy syndrome: A case report. Neuroradiol J. 2015 Dec;28(6):634-7. [PMC free article] [PubMed]](https://image.slidesharecdn.com/brainstem-250725070339-15b96b58/85/Brain_stem_Medulla-oblongata_functions-of-pons_mid-brain-15-320.jpg)
Brain_stem_Medulla oblongata_functions of pons_mid brain
- 1. BRAIN STEM Dr. E. Muralinath, Dr. M. Guruprasad, Dr. K. Sravani Pragna, Dr. C. Kalyan, Dr. P. Manjari, Dr. D. Kusumalatha, Dr. K. Sridevi , Dr. Ch. Ramya Sudha and R. Gnana Lahari
- 2. • INTRODUCTION • Brainstem is the part of brain and it is formed by medulla oblongata, pons and midbrain. 2)Brainstem consists of ascending and descending tracts between brain and • spinal cord. • 3)It also consists of many centers for regulation of vital functions in the body. • MEDULLA OBLONGATA • Medulla oblongata or medulla is the lowermost part of brain. • It is located below pons and is continued downwards as spinal cord. • Medulla forms the main pathway for ascending and descending tracts of the spinal cord. • It also consists of many important centers which regulate the vital functions.
- 3. • 1. Respiratory Centers • Dorsal and ventral group of neurons form the medullary respiratory centers, which control normal rhythmic respiration. • 2. Vasomotor Center • Vasomotor center regulates blood pressure and heart rate. • 3. Deglutition Center • Deglutition center controls the pharyngeal and esophageal stages of deglutition. • 4. Vomiting Center • Vomiting center causes vomiting particularly during irritation or inflammation of gastrointestinal (GI) tract.
- 4. • 5. Superior and Inferior Salivatory Nuclei • Salivatory nuclei regulate the secretion of saliva. • 6. Cranial Nerve Nuclei • A) Nuclei of 12th, 11th, 10th and some nuclei of 8th and 5th cranial nerves are situated in the medulla oblongata. • B) 12th cranial (hypoglossal) nerve regulates the movements of tongue. • C) 11th cranial (accessory) nerve regulates the movements of shoulder and 10th cranial (vagus) nerve controls almost all the vital functions in the body, viz. cardiovascular system, respiratory system, GI system, etc. • D) 8th cranial nerve (the cochlear division of this nerve), which has the relay in medulla oblongata, is associated with with the auditory function.
- 5. • 7. Vestibular Nuclei • A) Vestibular nuclei consist of the second order neurons of vestibular nerve. • B) There are four vestibular nuclei, located in the rostral part of medulla and caudal part of pons, namely superior, medial, lateral and inferior vestibular nuclei. Medial and inferior vestibular nuclei extend into medulla. • C) Inferior colliculus is the center for auditory reflexes. • D) Activation of this also produces reflex vocalization. •
- 6. • PONS • Pons leads to the formation of a bridge between medulla and midbrain. • Functions of Pons • 1. Axons of pontine nuclei join to form the middle cerebellar peduncle or the brachium pontis. Pons forms the pathway that connects cerebellum along with cerebral cortex. • 2. Pyramidal tracts pass through the pons • 3. Medial lemniscus is joined by the fibers of 10th, 9th, 7th and 5th cranial nerves in pons • 4. Nuclei of 8th, 7th, 6th and 5th cranial nerves are • located in pons • 5. Pons consists of the pneumotaxic and apneustic centers for regulation of respiration • 6. It also contains the vestibular nuclei, which are already mentioned in medulla oblongata.
- 7. • MIDBRAIN • Midbrain is located between pons and diencephalon. It • Contains two parts: • A. Tectum • B. Cerebral peduncles. • TECTUM • The formatiom of tectum takes place by two structures: • 1. Superior colliculus • 2. Inferior colliculus.
- 8. • 1. Superior Colliculus • A) Superior colliculus is a small structure and is an important center for reflexes. • B) Through tectospinal tract, superior colliculus regulates the movements of the eyes, head, trunk and limbs, in response to visual impulses. • C) Efferent fibers from superior colliculus going to the nucleus of III cranial (oculomotor) nerve result in constriction of pupil during light reflex. Thus, it forms the center for light reflex. • D) Superior colliculus also receives afferents from optic tract, which assists in the integration of optical and postural reflexes. • 2. Inferior Colliculus • Inferior colliculus contains single layer of neurons to which the lateral lemniscus (auditory fibers) synapses. •
- 9. • CEREBRAL PEDUNCLES • Cerebral peduncles include: • 1. Basis pedunculi • 2. Substantia nigra • 3. Tegmentum, which includes red nucleus. • 1. Basis Pedunculus • Basis pedunculus contains pyramidal tract fibers in the middle, temporopontine fibers laterally and frontopontine fibers medially. • 2. Substantia Nigra • Substantia nigra is located below the red nucleus. Substantia nigra is treated as one of the components of basal ganglia . • 3. Tegmentum • Tegmentum lies dorsal to substantia nigra and is actually the upward continuation of the reticular formation in pons. Tegmentum consists of three decussations and red nucleus.
- 10. • Decussations in tegmentum • i. Superior cerebellar peduncle, which is formed by fibers between cerebellum and other parts of CNS. These fibers are predominantly efferent fibers from dentate nucleus of cerebellum; few fibers are from other cerebellar nuclei namely nucleus globosus and nucleus emboliformis. • ii. Forel decussation, which is due to the crossing of rubrospinal tracts from either side • iii. Meynert decussation, which is because of the crossing of medial longitudinal bundle that is formed by efferent fibers of 3rd, 4th and 6th cranial nerves.
- 11. • Red Nucleus • Red nucleus is a large oval or round mass of gray matter, extending between the superior colliculus and hypothalamus. • Parts of red nucleus • Red nucleus has two parts: • 1. Nucleus magnocellularis, which is formed by large cells. Fibers from this form the rubrospinal and rubrobulbar tracts. All the medullary centers and nuclei of cranial nerves • are controlled by higher centers, situated in cerebral cortex and hypothalamus. • 2. Nucleus parvocellularis, which is formed by smaller cells. Fibers from this form mainly the rubroreticular tract.
- 12. • Connections of red nucleus • Afferent connections: Red nucleus receives fibers from: • 1. Nucleus parvocellularis, which receives fibers from motor cortex (area 6) – corticorubral fibers . • 2. Nucleus magnocellularis, which receives fibers from motor cortex (area 6) – pallidorubral fibers • 3. Nucleus magnocellularis, which receives fibers from dentate nucleus (of opposite side) – cerebellorubral or dentatorubral tract. • Efferent connections: • Red nucleus sends efferent fibers to various parts of brain and spinal cord: • 1. Rubrospinal tract to spinal cord . • 2. Rubrobulbar tract to medulla • 3. Rubroreticular fibers to reticular formation • 4. Rubrothalamic tract to lateral ventral nucleus of • thalamus • 5. Rubro olivary tract to inferior olivary nucleus • 6. Fibers to nuclei of 3rd, 4th and 6th cranial nerves. •
- 13. • Functions of red nucleus • 1. Control of muscle tone: Due to its connections • with cerebellum, vestibular apparatus and skeletal muscle, the red nucleus plays an important role regarding the facilitation of the muscle tone. • 2. Control of complex muscular movements: • Red nucleus regulates the complex muscular movements. It plays an important role in the • integration of various impulses received from many important areas of brain. • 3. Control of righting reflexes: Red nucleus is the center for all righting reflexes except optical righting reflexes . • 4. Control of movements of eyeball: Through its efferent connections with nuclei of 3rd, 4th and 6th cranial nerves, red nucleus plays an important role regarding the regulation of ocular movements (Chapter 165). • 5. Control of skilled movements: Red nucleus plays an important role in controlling the skilled muscular movements by its connections with spinal cord as well as cerebral cortex.
- 14. References • 1. • Oliva I, Wanat MJ. Ventral Tegmental Area Afferents and Drug-Dependent Behaviors. Front Psychiatry. 2016;7:30. [PMC free article] [ PubMed] • 2. • Samineni VK, Premkumar LS, Faingold CL. Neuropathic pain-induced enhancement of spontaneous and pain-evoked neuronal activity in the periaqueductal gray that is attenuated by gabapentin. Pain. 2017 Jul;158(7):1241-1253. [PMC free article] [PubMed] • 3. • Zelenin PV, Beloozerova IN, Sirota MG, Orlovsky GN, Deliagina TG. Activity of red nucleus neurons in the cat during postural corrections. J Neurosci. 2010 Oct 27;30(43):14533-42. [PMC free article] [PubMed] • 4. • Mather M, Harley CW. The Locus Coeruleus: Essential for Maintaining Cognitive Function and the Aging Brain. Trends Cogn Sci. 2016 Mar;20(3):214-226. [PMC free article] [PubMed] • 5. • Dutschmann M, Dick TE. Pontine mechanisms of respiratory control. Compr Physiol. 2012 Oct;2(4):2443-69. [PMC free article] [ PubMed] • 6. • Angeles Fernández-Gil M, Palacios-Bote R, Leo-Barahona M, Mora-Encinas JP. Anatomy of the brainstem: a gaze into the stem of life. Semin Ultrasound CT MR. 2010 Jun;31(3):196-219. [PubMed] • 7. • Brown RE, Basheer R, McKenna JT, Strecker RE, McCarley RW. Control of sleep and wakefulness. Physiol Rev. 2012 Jul;92(3):1087-187. [PMC free article] [PubMed] • 8. • Javed K, Reddy V, Lui F. StatPearls [Internet]. StatPearls Publishing; Treasure Island (FL): Jul 24, 2023. Neuroanatomy, Lateral Corticospinal Tract. [PubMed]
- 15. • 9. • Al-Chalabi M, Reddy V, Gupta S. StatPearls [Internet]. StatPearls Publishing; Treasure Island (FL): Aug 14, 2023. Neuroanatomy, Spinothalamic Tract. [PubMed] • 10. • Navarro-Orozco D, Bollu PC. StatPearls [Internet]. StatPearls Publishing; Treasure Island (FL): Aug 7, 2023. Neuroanatomy, Medial Lemniscus (Reils Band, Reils Ribbon) [PubMed] • 11. • Saldaña E, Aparicio MA, Fuentes-Santamaría V, Berrebi AS. Connections of the superior paraolivary nucleus of the rat: projections to the inferior colliculus. Neuroscience. 2009 Sep 29;163(1):372-87. [PMC free article] [PubMed] • 12. • Bressan M, Davis P, Timmer J, Herzlinger D, Mikawa T. Notochord-derived BMP antagonists inhibit endothelial cell generation and network formation. Dev Biol. 2009 Feb 01;326(1):101-11. [PMC free article] [PubMed] • 13. • Dupont G, Schmidt C, Yilmaz E, Oskouian RJ, Macchi V, de Caro R, Tubbs RS. Our current understanding of the lymphatics of the brain and spinal cord. Clin Anat. 2019 Jan;32(1):117-121. [PubMed] • 14. • Lipovsek M, Wingate RJ. Conserved and divergent development of brainstem vestibular and auditory nuclei. Elife. 2018 Dec 19;7 [PMC free article] [PubMed] • 15. • Tortora F, Caranci F, Belfiore MP, Manzi F, Pagliano P, Cirillo S. Brainstem variant of posterior reversible encephalopathy syndrome: A case report. Neuroradiol J. 2015 Dec;28(6):634-7. [PMC free article] [PubMed]