DOCSLIB.ORG

The Cerebellum

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Cerebellum 2014/4/11 General View of Cerebellum 10 % total volume of the brain, but >50% of all its neurons The Cerebellum Provided with extensive information (40 times more axons project into the cerebellum than exit from it) Not necessary to basic elements of perception or movement. 陽明大學醫學院 腦科所 Damage to the cerebellum disrupts the spatial accuracy 陳昌明 副教授 and temporal coordination of movement. It impairs balance and reduces muscle tone and motor learning and certain cognitive functions. Position Lies above and behind the medullar and pons and occupies posterior cranial fossa Cerebellum Cerebellum external configuration • Located in posterior cranial fossa • Tentorium cerebelli (cerebrum), 4th ventricle (brain stem) • Communicate with other structure via •superior, middle, and inferior cerebellar peduncle 1 2014/4/11 External features External features Consists of two cerebellar hemisphere united in the Three peduncles midline by the vermis Inferior cerebellar peduncle 下小腦脚 －connect with medulla and with spinal cord, contain both afferent and efferent fibers Middle cerebellar peduncle 中小腦脚－connect with pons, contain afferent fibers Superior cerebellar peduncle 上小腦脚－connect with midbrain, contain mostly efferent fibers Cerebellum Lobes Anterior lobe corpus of Primary fissure cerebellar Longitudinal division Posterior lobe Vermis, Paravermal Region, Cerebellar Hemisphere Transverse division Flocculonodular lobe Anterior Lobe Posterolateral fissure Posterior Lobe Flocculonodular Lobe Lobes External features Superior surface Two deep fissures Primary fissure Tonsil of cerebellum 小腦扁桃体 two elevated Posterosuperior fissure masses on inferior Three lobs surface of hemispheral Flocculonodular lobe 絨球小結葉 portion just nearby flocculus and nodule foramen magnum Anterior lobe Corpus of cerebellar Posterior lobe Tonsil View from below 2 2014/4/11 External features Cerebellum & Brainstem, Inferior Surface, Anterior View Internal structures Deep Nuclei Gray matter Cerebellar cortex Cerebellar nuclei Dentate nucleus 齒狀核 1. fastigial Fastigial nucleus 頂核 nucleus Interposed nucleus 中間核 2. globose Emboliform nucleus 栓狀核 nucleus Globose nucleus球狀核 3. emboliform White matter－medullary nucleus center 髓体 4. dentate nucleus Internal structures Cerebellar cortex Fastigial nucleus Globose nucleus Dentate nucleus Emboliform nucleus medullary center 3 2014/4/11 1. Purkinje cell 2. granule cell 3. basket cell 4. Golgi cell 5. stellate cell 6. climbing fiber 7. mossy fiber 8. parallel fiber 9. inferior olivary nucleus 10. deep cerebellar nuclei Neurons in the cerebellar cortex are organized Cerebellar Cortex into three layers Inputs Climbing fibers •from Inferior olive Mossy fibers Output Purkinje neurons Interneurons Granule neurons Stellate neurons Basket neurons Molecular Golgi neurons Purkinje Granular NTA Fig. 13-11 The Purkinje Cells Receive Excitatory Input From Two Geometrical Plan of Afferent Fiber Parallel and Systems and Are Climbing fibers Inhibited by Three Local Interneurons 4 2014/4/11 Mossy and Climbing Fibers Encode Peripheral Climbing Fiber Activity Produces Long-Lasting and Descending Information Differently Effects on the Synaptic Efficacy of Parallel Fiber Simple and complex spikes recorded intracellularly from Purkinje cells Complex spikes (right bracket) are evoked by climbing fiber synapses, while simple spikes (left bracket) are produced by mossy fiber input. Cerebellum ：Internal Configurations Cerebellar Cortex Molecular Layer Stellate Cell --- taurine (inhibitory) afferent: parallel fiber efferent: Purkinje cell dendrite Basket Cell ---- GABA (inhibitory) afferent: parallel fiber efferent: Purkinje cell soma Parallel Fiber granule cell axon Purkinje Cell Dendrite Mossy fibers A mossy fiber is an axon terminal that ends in a large, bulbous swelling. Enter the granule cell layer and synapse on the dendrites of granule cells (right) In fact the granule cells reach out with little "claws" to grasp the terminals. The granule cells then send their axons up to the molecular layer, where they end in a T and run parallel to the surface, thus called parallel fibers. The parallel fibers synapse on the huge dendritic arrays of the Purkinje cells. 5 2014/4/11 Mossy fibers The climbing fiber Although each parallel fiber touches each It goes straight to the Purkinje cell layer and Purkinje cell only once, the thousands of parallel snake up the Purkinje dendrites, like ivy climbing fibers working together can drive the Purkinje a trellis. cells to fire like mad. Each climbing fiber associates with only one Purkinje cell, but when the climbing fiber fires, it provokes a large response in the Purkinje cell. Cerebellar cortex Cerebellum: Internal Configurations Cerebellar Cortex Purkinje Cell Layer interneurons All are inhibitory interneurons. Purkinje Cell The Golgi cell is found among the granule cells. -- 15,000,000 in number The stellate and basket cells live in the molecular layer. -- GABA (inhibitory) The basket cell (right) drops axon branches down into afferent from: parallel fiber the Purkinje cell layer where the branches wrap around climbing fiber the cell bodies like baskets. stellate cell basket cell efferent to: deep cortical nuclei Bergman’s glial cell 6 2014/4/11 Cerebellum: Internal Configurations Cerebellar Cortex Granular Layer Granular Cell -- 50,000,000,000 in number -- glutamic acid (excitatory) afferent: mossy fiber efferent: Purkinje cell dendrite basket cell, stellate cell Golgi cell Golgi Cell -- GABA (inhibitory) afferent: parallel fiber, mossy fiber rosette efferent: granule cell dendrite Cerebellum: Internal Configurations Neurons in the Cerebellar Cortex Synaptic Glomerulus Afferent terminals on granular layer Mossy Fiber Rosette -- afferent fibers except inferior olivary input -- 2/3 of medullary center Granular Cell Dendrite A glomerulus is a -- main afferent input clear space where the bulbous terminal of a Golgi Cell Axon mossy fiber makes -- synapse on granule cell dendrite synaptic contact with -- GABA (inhibitory) Golgi and granule cells. - Surrounded by Astrocyte Foot Process Synaptic Glomerulus Cerebellum Classifications Classification by Phylogenetic and Ontogenic Development Archicerebellum Paleocerebllum Neocerebellum Classification by Afferent Connection Vestibulocerebellum Spinocerebellum Pontocerebellum Classification by Efferent Connection Vermis Paravermal Region Cerebellar Hemisphere 7 2014/4/11 Archicerebellum (nodulus) Spinocerebellum Archicerebellum (flocculus) Pontocerebellum Paleocerebellum Neocerebellum Vestibulocerebellum Cerebellum Connections Cerebellum Connections Afferent Connections (2): Afferent Connections (1): 2. Middle Cerebellar Peduncle 1. Inferior Cerebellar Peduncle Pontocerebellar fiber Restiform Body Corticopontocerebellar Fiber Posterior Spinocerebellar Tract Reticulocerebellar Fiber Olivocerebellar tract 3. Superior Cerebellar Peduncle Cuneocerebellar Tract Anterior Spinocerebellar Tract Reticulocerebellar Tract Cerulocerebellar fiber Juxtarestiform Body Raphecerebellar fiber Vestibulocerebellar Tract Rubrocerebellar fiber Primary Vestibular Fiber Hypothalamocerebellar fiber Cerebellum Connections Three functional divisions Efferent Connections : Vestibulocerebellum 1. Superior Cerebellar Peduncle 前庭小腦 Archicerebellum 原小腦 Cerebellothalamic fiber Flocculonodular lobe Intermediate zone Intermediate Vermis - from 3 deep nuclei to VPLo, VLc, CL Spinocerebellum zone Lateral 脊髓小腦 Cerebellorubral fiber Paleocerebellum 舊小腦 - from nucleus interpositus & dentate nucleus Vermis and Ascending portion of uncinate fasciculus of Russell intermediate zone 2. Inferior Cerebellar Peduncle Cerebrocerebellum 大腦小腦 Flocculonodular lobe Fastigiovestibular fiber Neocerebellum 新小腦 Descending portion of uncinate fasciculus of Russell Lateral zone 8 2014/4/11 Functional divisions of cerebellar cortex The Cerebellum Has Three Functionally Distinct Regions The Three Functionally Distinct Regions Cerebellar divisions Have different inputs and outputs Spinocerebellum: Vermis Spinocerebellum Intermediate hem. (Vermis + Intermed. Hem) Cerebrocerebellum: Lateral hem. Control of limbs and trunk Cerebrocerebellum (Lateral hemisphere) Planning of movement+ Vermis IVth vent Vestibulo-cerebellum Intermediate hem. (Floculo-nodular lobe) Lateral hem. Control of eye & head movements Balance NTA Fig. 13-1 Floculo-nodular lobe Connections and function of cerebellum Vestibulo-cerebellum Vestibulocerebellum Connections Input: Afferents: receive input from vestibular nuclei and vestibular primary vestibular nuclei Efferents: projects to the vestibular nucleus → Output: (1) vestibulospinal tract → motor neurons of anterior horn vestibular for reflexively control of equilibrium nuclei (2) vestibulo-ocular tract → medial longitudinal fasciculus → CN nucleus 3, 4, 6 for EOM control. Function: involved in eye movements and maintain balance 9 2014/4/11 Main Connections of the Vestibulocerebellum Vestibular Organ Floculonodular Lobe BILATERAL VESTIBULAR NUCLEUS Vestibulospinal Tract MLF FASTIGIAL NUCLEUS Lower motor neuron ARCHICEREBELLUM LMN Spinocerebellum (vermis & intermediate) Spinocerebellum Input: periphery and spinal cord Output: cortex Afferents: Spinocerebellar tracts The Ventral and dorsal spinocerebellar End mainly in the anterior lobe, the paramedian lobule, and the pyramis of the posterior lobe tracts 10 2014/4/11 The efferents Connections and Function of Neo- cerebellum Vermis projects to the fastigial nucleus → vestibular nuclei and
Load more

Recommended publications
  • Anatomy of Cerebellum Rajasekhar Sajja Srinivasa Siva Naga
    Chapter Anatomy of Cerebellum Rajasekhar Sajja Srinivasa Siva Naga Abstract The cerebellum receives inputs from spinal cord, cerebrum, brainstem, and sensory systems of the body and controls the motor system of the body. The Cerebellum harmonizes the voluntary motor activities such as maintenance of posture and equilibrium, and coordination of voluntary muscular activity including learning of the motor behaviours. Cerebellum occupies posterior cranial fossa, and it is relatively a small part of the brain. It weighs about one tenth of the total brain. Cerebellar lesions do not cause motor or cognitive impairment. However, they cause slowing of movements, tremors, lack of equilibrium/balance. Complex motor action becomes shaky and faltering. Keywords: Cerebellum, Spinocerebellar ataxia, Cortex, Medulla, Peduncles, Nuclei 1. Introduction The Cerebellum is the largest part of the hindbrain and develops from the alar plates (rhombic lips) of the metencephalon. It lies between the temporal and occipital lobes of cerebrum and the brainstem in the posterior cranial fossa. It is attached to the posterior surface of the brainstem by three large white fibre bundles. It is attached to the midbrain by superior cerebel- lar peduncle, pons by middle cerebellar peduncle, and medulla by inferior cerebellar peduncle. Cerebellum is concerned with three primary functions: a) coordination of voluntary motor functions of the body initiated by the cerebral cortex at an uncon- scious level, b) maintenance of balance, and posture, c) Maintenance of muscle tone. It receives and integrates the sensory inputs from the cerebrum and the spinal cord necessary for a planning and smooth coordination of the movements [1]. Cerebellar lesions result in irregular and uncoordinated, awkward intentional muscle movements.
    [Show full text]
  • Anatomy of Cerebellum and Relevant Connections
    Anatomy of Cerebellum and Relevant Connections Lecture (14) . Important . Doctors Notes Please check our Editing File . Notes/Extra explanation هذا العمل مبني بشكل أساسي على عمل دفعة 436 مع المراجعة {ومنْْيتو َ ّكْْع َلْْا ِّْللْفَهُوْْحس بهْ} َ َ َ َ َ َ َ َ َ ُ ُ والتدقيق وإضافة المﻻحظات وﻻ يغني عن المصدر اﻷساسي للمذاكرة . Objectives At the end of the lecture, students should be able to: Describe the External features of the cerebellum (lobes, fissures). Describe briefly the Internal structure of the cerebellum. List the name of Cerebellar Nuclei. Relate the Anatomical to the Functional Subdivisions of the cerebellum. Describe the Important connections of each subdivision. Describe briefly the Main Effects in case of lesion of the cerebellum. Cerebellum o Origin: from Hindbrain. Playlist o Position: lies behind Pons & Medulla Separated from them by Fourth ventricle. o Connection: to the brainstem by Inferior, Middle & Superior Cerebellar Peduncles. (medulla) (pons) (midbrain) Extra Cerebellum has 3 fissures: - 2 main (primary) fissures (related to lobes): primary and secondary Cerebellum (posterolateral) - Horizontal fissure (largest/deepest) External Features and not related to lobes o Superior It consists of two Cerebellar Hemispheres joined vermis in midline by the Vermis. and paravermis (intermediate zone) is between vermis and hemisphere inferior o Its surface is highly convoluted forming Folia vermis (like gyri), separated by Fissures (like sulci). Anatomical Subdivision 1. Anterior lobe: in front of primary fissure, on the superior surface. 2. Posterior (middle) lobe: behind primary fissure (Between Primary & Secondary/posterolateral fissures). 3. Flocculonodular lobe: in front of secondary (Posterolateral) fissure, on the inferior surface .
    [Show full text]
  • The Stellate Cells of the Rat's Cerebellar Cortex*
    Z. Anat. Entwickl.-Gesch. 136, 224--248 (1972) by Springer-Verlag 1972 The Stellate Cells of the Rat's Cerebellar Cortex* Victoria Chan-Palay and Sanford L. Palay Departments of Neurobiology and Anatomy, Harvard Medical School, Boston, Massachusetts Received February 18, 1972 Summary. Stellate cells were studied in rapid Golgi preparations and in electron micro- graphs. These small neurons can be classified on the basis of their position in the molecular layer and the patterns of their dendritic and axonal arborizations as follows: (1) superficial cells with short, contorted dendrites and a circumscribed axonal arbor (upper third of the molecular layer) ; (2) deep stellate cells with radiating, twisted dendrites and with long axons giving rise to thin, varicose collaterals (middle third of the molecular layer); (3) deep stellate cells with similar dendrites and long axons giving collaterals to the basket around the Purkinje cell bodies (middle third of the molecular layer). An important characteristic of the stellate cell axon is that it generates most of its collaterals close to its origin. Even in long axon cells, only a few collaterals issue from the more distant parts of the axon. These forms contrast with the basket cell, which sends out long, straighter dendrites, and an extended axon that first emits branches at some distance from its origin. Furthermore, basket cell axon collaterals are usually stout in contrast to the frail, beaded collaterals of the stellate cell axon. The two cell types are considered to be distinct. In electron micrographs stellate cells display folded nuclei and sparse cytoplasm with the characteristics usual for small neurons.
    [Show full text]
  • 14-Anatomy of the Cerebellum and the Relevant Connections
    Dr. Ahmed Fathalla Ibrahim Professor of Anatomy OBJECTIVES At the end of the lecture, students should: qDescribe the External features of the cerebellum (lobes, fissures). qDescribe briefly the Internal structure of the cerebellum. qList the name of Cerebellar Nuclei. qRelate the Anatomical to the Functional Subdivisions of the cerebellum. qDescribe the Important connections of each subdivision. qDescribe briefly the Main Effects in case of lesion of the cerebellum. • ORIGIN : CEREBELLUM • From Hindbrain. • Position : • lies behind Pons & Medulla Separated from them by Fourth ventricle. THE CEREBELLUM qCONNECTION TO BRAIN STEM: qby Inferior, Middle & Superior Cerebellar Peduncles. EXTERNAL FEATURES qIt consists of two Cerebellar Hemispheres joined in midline by the Vermis. qIts surface is highly convoluted forming Folia, separated by Fissures. ANATOMICAL SUBDIVISION Primary Fissure Superior Surface Posterolateral = Secondary Fissure Anterroinferior Surface 1. Anterior lobe: in front of primary fissure, on the superior surface. 2. Posterior (middle) lobe: behind primary fissure (Between Primary & Secondary fissures = posterolateral). 3. Flocculonodular lobe: in front of secondary (Posterolateral) fissure, on the inferior surface . ANATOMICAL SUBDIVISION CONSTITUENTS (Internal Structure and Nuclei of Cerebellum) 1. Outer grey matter: cerebellar cortex. 2. Inner white matter: cerebellar medulla. 3. Deeply seated nuclei in white matter: from medial to lateral: • Fastigial nucleus. • Globose nucleus. • Emboliform nucleus. • Dentate nucleus: largest one. CEREBELLAR CORTEX q Divided into 3 layers: 1. Outer molecular layer 2. Intermediate Purkinje cell layer 3. Inner granular layer CEREBELLAR MEDULLA AFFERENT FIBRES: q Climbing fibres: from inferior olivary nucleus, relay to purkinje cells q Mossy fibres: rest of fibres: 1. From vestibular nuclei 2. From spinal cord 3. From pons • They relay to granule cells which in turn relay to purkinje cells.
    [Show full text]
  • Homo Sapiens (445) MEDIUM (=IQR) HIGH
    Dataset: 445 anatomical parts from data selection: HS_mRNASeq_HUMAN_GL-1 Showing 2 measure(s) of 2 gene(s) on selection: HS-0 TMPRSS2 ACE2 Level of expression Homo sapiens (445) MEDIUM (=IQR) HIGH 0 1 2 3 4 5 6 7 8 9 10 11 samples avg. expr. Tissue 3435 1.42 gestational structure 4 1.92 extraembryonic tissue / fluid 4 1.92 placenta 4 1.92 alimentary system 721 3.93 gastrointestinal tract 519 4.83 mouth (oral cavity) 7 0.87 oral mucosa (unspecified) 4 1.13 salivary gland 3 0.54 stomach 34 2.82 gastric (stomach) region 31 2.90 stomach cardia 11 2.13 stomach body 11 4.06 pyloric antrum 9 2.42 intestine 463 5.14 large intestine 294 3.48 caecum (cecum) 7 3.17 apex of caecum (appendix) 3 1.96 colorectum 287 3.49 colon 207 3.60 colonic mucosa 84 3.43 proximal colon 35 3.20 proximal colonic mucosa 35 3.20 ascending colon 30 3.32 transverse colon 5 2.53 distal colon 31 2.94 distal colonic mucosa 31 2.94 descending colon 6 2.51 sigmoid colon 25 3.05 rectosigmoid colon 5 2.33 rectosigmoid junction 6 3.47 rectum 62 3.00 small intestine 168 8.07 ileum 157 8.36 ileal mucosa 76 8.78 esophagus (oesophagus) 15 1.60 liver and biliary system 130 1.50 liver 119 1.36 gall bladder 3 6.94 bile duct 8 1.56 intrahepatic bile duct 8 1.56 pancreas 72 1.83 pancreatic islet (islet of Langerhans) 70 1.87 circulatory system 791 0.21 cardiovascular system 26 3.51 heart 19 3.39 heart muscle (myocardium, cardiac muscle) 7 4.10 heart ventricle 3 3.88 heart left ventricle 3 3.88 left ventricle free wall 3 3.88 vascular system 7 3.83 blood vessel 7 3.83 artery 7 3.83 coronary
    [Show full text]
  • Nervous System
    Nervous system 1 CELLS IN CNS Ectodermal origin • Astrocytes Oligodendrocytes • Astrocytes: • blood brain barrier • 2 types • Fibrous astrocytes in white matter • Protoplasmic astrocytes in gray matter • Oligodendrocytes • Form myelin in CNS 2 Mesodermal origin Microglia • do not develop from cells of neural tube • They come from bone marrow. • These are called microglia • They resemble tissue macrophages. 3 NEURON 4 • Nerve has axon and dendrites and a cell body • Axon starts from axon hillock and ends in terminal buttons which contains vesicles with neurotransmitters. • Nodes of Ranvier: 1 micro metre constrictions, 1mm apart. • Nerve surrounded by myelin sheath . • Myelin formed by schwann cells in PNS but in CNS it is formed by Oligodendrogliocytes. • Transmisssion of transmitters by axoplasmic flow. 5 • Electric Potentials • Non Propagative Propagative. • ALL OR NONE LAW: If the threshold is attained, no change in action potential even if intensity of stimulus is increased. • Refractory Period • Absolute Relative • From firing level to 1/3 from this pt. to start of • Repolarisation after depolarisation. 6 • Myelinated fibres conduct faster • SALTATORY CONDUCTION: Jumping from one node to the other • Depolarisation due to entry of Na ions • Repolarisation due to efflux of K ions • Action potentials starts in axon hillock due to increased Na channels • Energy source is Na K ATP ase. 7 • In CNS neurons are surrounded by glial cells. • 3 types of neuroglia • 1) Microglia - Scavenger cells • 2)Oligodendrocytes :- Forms myelin • 3)Astrocytes: 2 types, Forms blood brain barrier • A) Fibrous • B) Protoplasmic 8 AP reaches pre synaptic terminal Ca Channels open Ca influx Fusion of vesicles with plasma memb Exocytosis 9 Release of neurotransmitter Endocytosis Endosome formation Budding of vesicles from endosome 10 PRESYNAPTIC INHIBITION: Axo axonal synapse Activation of Opening of Direct Presynaptic K channels inhibition Receptors Inc.Cl entry Inc.
    [Show full text]
  • Cerebellum and Activation of the Cerebellum IO ST During Nonmotor Tasks
    Cerebellum (Kandel & Schwartz & Jessell, 4th ed.) Granule186 cells are irreducibly smallChapter (6-8 7 μm) stellate cell basket cell outer synaptic layer PC rs cap PC layer grc Go inner 6 μm synaptic layer Figure 7.15 Largest cerebellar neuron occupies more than a 1,000-fold greater volume than smallest neuron. Thin section (~1 μ m) through monkey cerebellar cortex. Purkinje cell body (PC) and nucleus are far larger than those of granule cell (grc). The latter cluster to leave space for mossy fiber terminals to form glomeruli with grc dendritic claws and space for Golgi cells (Go). Note rich network of capillaries (cap). Fine, scat- tered dots are mitochondria. Courtesy of E. Mugnaini. brain ’ s most numerous neuron, this small cost grows large (see also chapter 13). Much of the inner synaptic layer is occupied by the large axon terminals of mossy fibers (figures 7.1 and 7.16). A terminal interlaces with multiple (~15) dendritic claws, each from a different but neighboring granule cell, and forms a complex knot (glomerulus ), nearly as large as a granule cell body (figures 7.1 and 7.16). The mossy fiber axon fires at an unusually high mean rate (up to 200 Hz) and is therefore among the brain’ s thickest (figure 4.6). To match the axon’ s high rate, a terminal expresses 150 active zones, 10 per postsynaptic granule cell (figure 7.16). These sites are capable of driving … and most expensive. 190 Chapter 7 10 4 8 3 9 19 10 10 × 6 × 2 2 4 ATP/s/cell ATP/s/cell ATP/s/m 1 2 0 0 astrocyte astrocyte Golgi cell Golgi cell basket cell basket cell stellate cell stellate cell granule cell granule cell mossy fiber mossy fiber Purkinje cell Purkinje Purkinje cell Purkinje Bergman glia Bergman glia climbing fiber climbing fiber Figure 7.18 Energy costs by cell type.
    [Show full text]
  • The Modifiable Neuronal Network of the Cerebellum
    Japanese Journal of Physiology, 34, 781-792, 1984 MINIREVIEW The Modifiable Neuronal Network of the Cerebellum M asao ITO Department of Physiology, Faculty of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, 113 Japan An outstanding feature of the cerebellum known since the classic histological work of Ramon y Cajal is the relative simplicity and highly ordered geometry of its neuronal network. The cerebellar neuronal network consists of five major types of cortical neurons (Purkinje, basket, stellate, Golgi, and granule cells), two major types of afferents (mossy and climbing fibers), and the subcortical cells in the vestibular and cerebellar nuclei. When the neuronal network structure of the cerebellum was comprehensively dissected and described in great detail in the 1960s, and summarized by ECCLES,ITO, and SZ.ENTAGOTHAI[8], it was taken as a challenge to understand more completely the complex functions of the central nervous system using these fundamental studies of the brain as groundwork for future elucidation. As the gap between our understanding of the brain and our knowledge of neuronal networks is in general so large, hope has arisen that cere- bellar physiology may successfully fill the gap rather soon. Rigorous efforts using numerous newly-introduced techniques have been devoted during the past two decades, yielding remarkable progress that meets expectations at least to some extent. A number of problems remain to be solved, however, before we fully understand the cerebellum. It seems important at this point to review the major achievements of the past two decades in order to gain a clearer perspective of cerebellar physiology for the coming decade.
    [Show full text]
  • Anatomy of Cerebellum & Relevant Connections
    Anatomy of Cerebellum & Relevant Connections Neuroanatomy block-Anatomy-Lecture 14 Editing file Objectives At the end of the lecture, students should be able to: ● Describe the external features of the cerebellum (lobes, fissures). ● Describe briefly the internal structure of the cerebellum. ● List the name of cerebellar nuclei. ● Relate the anatomical to the functional subdivisions of the cerebellum. ● Describe the important connections of each subdivision. ● Describe briefly the main effects in case of lesion of the cerebellum. Color guide ● Only in boys slides in Green ● Only in girls slides in Purple ● important in Red ● Notes in Grey The Cerebellum Origin : from hindbrain,lies behind Pons & Medulla Separated from them by Fourth ventricle. Connection To Brain Stem : by inferior, middle & superior cerebellar peduncles. External Features: It consists of two cerebellar hemispheres joined in midline by the vermis Its surface is highly convoluted forming folia separated by fissures. Anatomical Subdivision Posterior (middle) lobe: Flocculonodular lobe : Anterior lobe: in front behind primary fissure in front of secondary of primary fissure on (Between Primary & (Posterolateral) the superior surface. Secondary fissures fissure on the inferior = posterolateral) surface . 3 Constituents Internal Structure and Nuclei of Cerebellum Inner white matter: cerebellar medulla. Afferent Fibres: (4 afferent fibers) Deeply seated nuclei in ● Outer grey matter: Climbing fibres: (direct to purkinje cells). from inferior olivary nucleus, relay to purkinje cells white matter: ● cerebellar cortex Mossy fibres: (indirect to purkinje cells) rest of fibres: from medial to lateral: Divided into 3 layers: 1. From vestibular nuclei 2. From spinal cord 3. From pons 1. Fastigial: smallest one 1. Outer molecular layer They relay to granule cells which in turn relay to purkinje cells and most medial Finally all afferent fibres passing through the medulla relay to purkinje cells in the cortex.
    [Show full text]
  • Pathology of the Central Autonomic Nervous System in Stillbirth Luigi Matturri* and Anna Maria Lavezzi
    The Open Pediatric Medicine Journal, 2007, 1, 1-8 1 Pathology of the Central Autonomic Nervous System in Stillbirth Luigi Matturri* and Anna Maria Lavezzi “Lino Rossi” Research Center, Institute of Pathology, University of Milan, Italy Abstract: The aim of this study was to identify in stillbirth a possible involvement of morphological and/or physiological alterations of structures of the central autonomic nervous system in the mechanism of death. The study, including the in- depth histological examination of brainstem and cerebellum, was performed on 42 stillbirths, aged from 22 to 40 gesta- tional weeks, 12 of which were explained and 30 were unexplained deaths. In the sudden unexplained stillbirths a variety of morphological and/or biological abnormalities of different structures and nuclei was found, above all the hypoplasia of the parafacial complex, frequently associated with hypoplasia of the arcuate and pre-Bötzinger nuclei, and with thyrosine-hydroxylase immunonegativity in the locus coeruleus. A significant correla- tion was also observed between the neuropathologic findings and mother’s smoking habit. Keywords: Stillbirth, central autonomic nervous system, brainstem, neuropathology, developmental alterations. INTRODUCTION applied immunohistochemical methods to analyze the ex- pression of neurotransmitters (namely catecholamines and While society displays an increased awareness of sudden somatostatin) regulating important physiological functions infant death syndrome (SIDS), less attention has been fo- already from the first weeks of gestation [7-10] and gliosis, a cused on another form of unexplained death that occurs with process of astrocytic activation, indicative of a response to a greater frequency in late pregnancy, namely “stillbirth”. In central nervous system injury [11,12].
    [Show full text]
  • Spontaneous Activity Signatures of Morphologically Identified Interneurons in the Vestibulocerebellum
    712 • The Journal of Neuroscience, January 12, 2011 • 31(2):712–724 Behavioral/Systems/Cognitive Spontaneous Activity Signatures of Morphologically Identified Interneurons in the Vestibulocerebellum Tom J. H. Ruigrok,1 Robert A. Hensbroek,2 and John I. Simpson2 1Department of Neuroscience, Erasmus Medical Center Rotterdam, 3000 CA Rotterdam, The Netherlands, and 2Department of Physiology and Neuroscience, New York University School of Medicine, New York, New York 10016 Cerebellar cortical interneurons such as Golgi cells, basket cells, stellate cells, unipolar brush cells, and granule cells play an essential role in the operations of the cerebellum. However, detailed functional studies of the activity of these cells in both anesthetized and behaving animals have been hampered by problems in recognizing their physiological signatures. We have extracellularly recorded the spontane- ous activity of vestibulocerebellar interneurons in ketamine/xylazine-anesthetized rats and subsequently labeled them with Neurobiotin using the juxtacellular technique. After recovery and morphological identification of these cells, they were related to statistical measures of their spontaneous activity. Golgi cells display a somewhat irregular firing pattern with relatively low average frequencies. Unipolar brush cells are characterized by more regular firing at higher rates. Basket and stellate cells are alike in their firing characteristics, which mainly stand out by their irregularity; some of them are set apart by their very slow average rate. The spontaneous activity of interneurons examined in the ketamine/xylazine rabbit fit within this general pattern. In the rabbit, granule cells were identified by the spontaneous occurrence of extremely high-frequency bursts of action potentials, which were also recognized in the rat.
    [Show full text]
  • Cerebellar Cells
    NAME: AWOSAN SAMUEL OLUWAGBENGA MATRIC NUMBER: 17/MHS01/071 MEDICINE AND SURGERY ASSIGNMENT Write a concise review on the developmental genetics of the cerebellum and highlight the genetic bases of known cerebellar disorders Cerebellar Cells These drawings of cerebellar cells were based upon electron micrograph images from the rat cerebellum. • granule cell • Bergmann astrocyte • oligodendrocyte Purkinje Cell Search: Purkinje cell Development Historic Description Gray H. Anatomy of the human body . (1918) Philadelphia: Lea & Febiger. "The cerebellum is developed in the roof of the anterior part of the hind-brain (Figs. 649 to 654). The alar laminæ of this region become thickened to form two lateral plates which soon fuse in the middle line and produce a thick lamina which roofs in the upper part of the cavity of the hind- brain vesicle; this constitutes the rudiment of the cerebellum, the outer surface of which is originally smooth and convex. The fissures of the cerebellum appear first in the vermis and floccular region, and traces of them are found during the third month; the fissures on the cerebellar hemispheres do not appear until the fifth month. The primitive fissures are not developed in the order of their relative size in the adult—thus the horizontal sulcus in the fifth month is merely a shallow groove. The best marked of the early fissures are: (a) the fissura prima between the developing culmen and declive, and (b) the fissura secunda between the future pyramid and uvula. The flocculus and nodule are developed from the rhombic lip, and are therefore recognizable as separate portions before any of the other cerebellar lobules.
    [Show full text]