Both Pyramidal Tracts and Extrapyramidal Both Starts from Cortex
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NS201C Anatomy 1: Sensory and Motor Systems
NS201C Anatomy 1: Sensory and Motor Systems 25th January 2017 Peter Ohara Department of Anatomy [email protected] The Subdivisions and Components of the Central Nervous System Axes and Anatomical Planes of Sections of the Human and Rat Brain Development of the neural tube 1 Dorsal and ventral cell groups Dermatomes and myotomes Neural crest derivatives: 1 Neural crest derivatives: 2 Development of the neural tube 2 Timing of development of the neural tube and its derivatives Timing of development of the neural tube and its derivatives Gestational Crown-rump Structure(s) age (Weeks) length (mm) 3 3 cerebral vesicles 4 4 Optic cup, otic placode (future internal ear) 5 6 cerebral vesicles, cranial nerve nuclei 6 12 Cranial and cervical flexures, rhombic lips (future cerebellum) 7 17 Thalamus, hypothalamus, internal capsule, basal ganglia Hippocampus, fornix, olfactory bulb, longitudinal fissure that 8 30 separates the hemispheres 10 53 First callosal fibers cross the midline, early cerebellum 12 80 Major expansion of the cerebral cortex 16 134 Olfactory connections established 20 185 Gyral and sulcul patterns of the cerebral cortex established Clinical case A 68 year old woman with hypertension and diabetes develops abrupt onset numbness and tingling on the right half of the face and head and the entire right hemitrunk, right arm and right leg. She does not experience any weakness or incoordination. Physical Examination: Vitals: T 37.0° C; BP 168/87; P 86; RR 16 Cardiovascular, pulmonary, and abdominal exam are within normal limits. Neurological Examination: Mental Status: Alert and oriented x 3, 3/3 recall in 3 minutes, language fluent. -
Corticospinal Fibers
151 Brain stem Pyramids/Corticospinal Tract 1 PYRAMIDS - CORTICOSPINAL FIBERS The pyramids are two elongated swellings on the ventral aspect of the medulla. Each pyramid contains approximately 1,000,000 CORTICOSPINAL AXONS. As the name suggests, these axons arise from the cerebral cortex and descend to terminate within the spinal cord. The cortical cells that give rise to corticospinal axons are called Betz cells. As corticospinal axons descend from the cortex, they course through the internal capsule, the cerebral peduncle of the midbrain, and the ventral pons (you will learn about these structures later in the course so don’t worry about them now) and onto the ventral surface of the medulla as the pyramids (see below). When corticospinal axons reach the medulla they lie within the pyramids. The pyramids are just big fiber bundles that lie on the ventral surface of the caudal medulla. The fibers in the pyramids are corticospinal. It is important to REMEMBER: THERE HAS BEEN NO CROSSING YET! in this system. The cell bodies of corticospinal axons within the pyramids lie within the IPSILATERAL cerebral cortex. Brain stem 152 Pyramids/Corticospinal Tract At the most caudal pole of the pyramids the corticospinal axons cross over the midline and now continue their descent on the contralateral (to the cell of origin) side. This crossover point is called the PYRAMIDAL DECUSSATION. The crossing fibers enter the lateral funiculus of the spinal cord where they are called the LATERAL CORTICOSPINAL TRACT (“corticospinal” is not good enough, you have to call them lateral corticospinal; LCST - remember this one??). LCST axons exit the tract to terminate upon neurons in the spinal cord gray matter along its entire length. -
The Brain Stem Medulla Oblongata
Chapter 14 The Brain Stem Medulla Oblongata Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Central sulcus Parietal lobe • embryonic myelencephalon becomes Cingulate gyrus leaves medulla oblongata Corpus callosum Parieto–occipital sulcus Frontal lobe Occipital lobe • begins at foramen magnum of the skull Thalamus Habenula Anterior Epithalamus commissure Pineal gland • extends for about 3 cm rostrally and ends Hypothalamus Posterior commissure at a groove between the medulla and Optic chiasm Mammillary body pons Cerebral aqueduct Pituitary gland Fourth ventricle Temporal lobe • slightly wider than spinal cord Cerebellum Midbrain • pyramids – pair of external ridges on Pons Medulla anterior surface oblongata – resembles side-by-side baseball bats (a) • olive – a prominent bulge lateral to each pyramid • posteriorly, gracile and cuneate fasciculi of the spinal cord continue as two pair of ridges on the medulla • all nerve fibers connecting the brain to the spinal cord pass through the medulla • four pairs of cranial nerves begin or end in medulla - IX, X, XI, XII Medulla Oblongata Associated Functions • cardiac center – adjusts rate and force of heart • vasomotor center – adjusts blood vessel diameter • respiratory centers – control rate and depth of breathing • reflex centers – for coughing, sneezing, gagging, swallowing, vomiting, salivation, sweating, movements of tongue and head Medulla Oblongata Nucleus of hypoglossal nerve Fourth ventricle Gracile nucleus Nucleus of Cuneate nucleus vagus -
Meninges,Cerebrospinal Fluid, and the Spinal Cord
The Nervous System SPINAL CORD Spinal Cord Continuation of CNS inferior to foramen magnum (medulla) Simpler Conducts impulses to and from brain Two way conduction pathway Reflex actions Spinal Cord Passes through vertebral canal Foramen magnum L2 Conus medullaris Filum terminale Cauda equina Cervical Cervical spinal nerves enlargement Dura and arachnoid Thoracic mater spinal nerves Lumbar enlargement Conus medullaris Lumbar Cauda spinal nerves equina Filum (a) The spinal cord and its nerve terminale Sacral roots, with the bony vertebral spinal nerves arches removed. The dura mater and arachnoid mater are cut open and reflected laterally. Figure 12.29a Spinal Cord Spinal nerves 31 pairs Cervical and lumbar enlargements The nerves serving the upper and lower limbs emerge here Cervical Cervical spinal nerves enlargement Dura and arachnoid Thoracic mater spinal nerves Lumbar enlargement Conus medullaris Lumbar Cauda spinal nerves equina Filum (a) The spinal cord and its nerve terminale Sacral roots, with the bony vertebral spinal nerves arches removed. The dura mater and arachnoid mater are cut open and reflected laterally. Figure 12.29a Spinal Cord Protection Bone, meninges, and CSF Spinal tap-inferior to second lumbar vertebra T12 Ligamentum flavum L5 Lumbar puncture needle entering subarachnoid space L4 Supra- spinous ligament L5 Filum terminale S1 Inter- Cauda equina vertebral Arachnoid Dura in subarachnoid disc matter mater space Figure 12.30 Spinal Cord Cross section Central gray matter Cortex of white matter Epidural -
Visualization of the Pyramidal Decussation Utilizing Diffusion
OPEN ACCESS RESEARCH Visualization of the pyramidal decussation utilizing diffusion tensor imaging: a feasibility study utilizing generalized q-sampling imaging Erik H Middlebrooks1,*, Jeffrey A Bennett1, Sharatchandra Bidari1, and Alissa Old Crow1 1Department of Radiology, University of Florida College of Medicine, Gainesville, Florida, USA *corresponding author ([email protected]) Abstract Background: The delineating point of the end of the brainstem and beginning of the spinal cord is known as the cervicomedullary junction (CMJ). This point is defined by the decussation of the pyramidal tracts. Abnormal configuration and location of the CMJ have both been implicated in disease processes such as Chiari malformation. Unfortunately, the CMJ is not directly visualized on contemporary imaging techniques. Diffusion tensor imaging (DTI) has given us the ability to directly visualize white matter tracts, but suffers from difficulties with visualizing crossing fibers. Many advanced techniques for visualizing crossing fibers utilize substantially long imaging times or non-clinical magnet strengths making clinical applicability limited. Objective: This study inves- tigates the use of generalized q-sampling imaging with diffusion decomposition on standard DTI acquisitions at 3 Tesla to demonstrate the pyramidal decussation. Methods: Three differing DTI protocols were analyzed in vivo with scan times of 17 minutes, 10 minutes, and 5.5 minutes. Data was processed with standard DTI post-processing, as well as generalized q-sampling imaging with diffusion decomposition. Results: The results of the study show that the pyramidal decussation can be reliably visualized using generalized q-sampling imaging and diffusion decomposition with scan times as low at 10 minutes. Conclusion: Utilizing generalized q-sampling post-processing, the pyramidal decussation can be reliably visualized using clinically feasible DTI sequences with scan times as low as 10 minutes. -
White Matter Tracts - Brain A143 (1)
WHITE MATTER TRACTS - BRAIN A143 (1) White Matter Tracts Last updated: August 8, 2020 CORTICOSPINAL TRACT .......................................................................................................................... 1 ANATOMY .............................................................................................................................................. 1 FUNCTION ............................................................................................................................................. 1 UNCINATE FASCICULUS ........................................................................................................................... 1 ANATOMY .............................................................................................................................................. 1 DTI PROTOCOL ...................................................................................................................................... 4 FUNCTION .............................................................................................................................................. 4 DEVELOPMENT ....................................................................................................................................... 4 CLINICAL SIGNIFICANCE ........................................................................................................................ 4 ARTICLES .............................................................................................................................................. -
Review of Spinal Cord Basics of Neuroanatomy Brain Meninges
Review of Spinal Cord with Basics of Neuroanatomy Brain Meninges Prof. D.H. Pauža Parts of Nervous System Review of Spinal Cord with Basics of Neuroanatomy Brain Meninges Prof. D.H. Pauža Neurons and Neuroglia Neuron Human brain contains per 1011-12 (trillions) neurons Body (soma) Perikaryon Nissl substance or Tigroid Dendrites Axon Myelin Terminals Synapses Neuronal types Unipolar, pseudounipolar, bipolar, multipolar Afferent (sensory, centripetal) Efferent (motor, centrifugal, effector) Associate (interneurons) Synapse Presynaptic membrane Postsynaptic membrane, receptors Synaptic cleft Synaptic vesicles, neuromediator Mitochondria In human brain – neurons 1011 (100 trillions) Synapses – 1015 (quadrillions) Neuromediators •Acetylcholine •Noradrenaline •Serotonin •GABA •Endorphin •Encephalin •P substance •Neuronal nitric oxide Adrenergic nerve ending. There are many 50-nm-diameter vesicles (arrow) with dark, electron-dense cores containing norepinephrine. x40,000. Cell Types of Neuroglia Astrocytes - Oligodendrocytes – Ependimocytes - Microglia Astrocytes – a part of hemoencephalic barrier Oligodendrocytes Ependimocytes and microglial cells Microglia represent the endogenous brain defense and immune system, which is responsible for CNS protection against various types of pathogenic factors. After invading the CNS, microglial precursors disseminate relatively homogeneously throughout the neural tissue and acquire a specific phenotype, which clearly distinguish them from their precursors, the blood-derived monocytes. The ´resting´ microglia -
Brainstem and Its Associated Cranial Nerves
Brainstem and its Associated Cranial Nerves Anatomical and Physiological Review By Sara Alenezy With appreciation to Noura AlTawil’s significant efforts Midbrain (Mesencephalon) External Anatomy of Midbrain 1. Crus Cerebri (Also known as Basis Pedunculi or Cerebral Peduncles): Large column of descending “Upper Motor Neuron” fibers that is responsible for movement coordination, which are: a. Frontopontine fibers b. Corticospinal fibers Ventral Surface c. Corticobulbar fibers d. Temporo-pontine fibers 2. Interpeduncular Fossa: Separates the Crus Cerebri from the middle. 3. Nerve: 3rd Cranial Nerve (Oculomotor) emerges from the Interpeduncular fossa. 1. Superior Colliculus: Involved with visual reflexes. Dorsal Surface 2. Inferior Colliculus: Involved with auditory reflexes. 3. Nerve: 4th Cranial Nerve (Trochlear) emerges caudally to the Inferior Colliculus after decussating in the superior medullary velum. Internal Anatomy of Midbrain 1. Superior Colliculus: Nucleus of grey matter that is associated with the Tectospinal Tract (descending) and the Spinotectal Tract (ascending). a. Tectospinal Pathway: turning the head, neck and eyeballs in response to a visual stimuli.1 Level of b. Spinotectal Pathway: turning the head, neck and eyeballs in response to a cutaneous stimuli.2 Superior 2. Oculomotor Nucleus: Situated in the periaqueductal grey matter. Colliculus 3. Red Nucleus: Red mass3 of grey matter situated centrally in the Tegmentum. Involved in motor control (Rubrospinal Tract). 1. Inferior Colliculus: Nucleus of grey matter that is associated with the Tectospinal Tract (descending) and the Spinotectal Tract (ascending). Tectospinal Pathway: turning the head, neck and eyeballs in response to a auditory stimuli. 2. Trochlear Nucleus: Situated in the periaqueductal grey matter. Level of Inferior 3. -
ON-LINE FIG 1. Selected Images of the Caudal Midbrain (Upper Row
ON-LINE FIG 1. Selected images of the caudal midbrain (upper row) and middle pons (lower row) from 4 of 13 total postmortem brains illustrate excellent anatomic contrast reproducibility across individual datasets. Subtle variations are present. Note differences in the shape of cerebral peduncles (24), decussation of superior cerebellar peduncles (25), and spinothalamic tract (12) in the midbrain of subject D (top right). These can be attributed to individual anatomic variation, some mild distortion of the brain stem during procurement at postmortem examination, and/or differences in the axial imaging plane not easily discernable during its prescription parallel to the anterior/posterior commissure plane. The numbers in parentheses in the on-line legends refer to structures in the On-line Table. AJNR Am J Neuroradiol ●:●●2019 www.ajnr.org E1 ON-LINE FIG 3. Demonstration of the dentatorubrothalamic tract within the superior cerebellar peduncle (asterisk) and rostral brain stem. A, Axial caudal midbrain image angled 10° anterosuperior to posteroinferior relative to the ACPC plane demonstrates the tract traveling the midbrain to reach the decussation (25). B, Coronal oblique image that is perpendicular to the long axis of the hippocam- pus (structure not shown) at the level of the ventral superior cerebel- lar decussation shows a component of the dentatorubrothalamic tract arising from the cerebellar dentate nucleus (63), ascending via the superior cerebellar peduncle to the decussation (25), and then enveloping the contralateral red nucleus (3). C, Parasagittal image shows the relatively long anteroposterior dimension of this tract, which becomes less compact and distinct as it ascends toward the thalamus. ON-LINE FIG 2. -
Closed-Loop Neuromodulation Restores Network Connectivity And
RESEARCH ARTICLE Closed-loop neuromodulation restores network connectivity and motor control after spinal cord injury Patrick D Ganzer1,2*, Michael J Darrow1, Eric C Meyers1,2, Bleyda R Solorzano2, Andrea D Ruiz2, Nicole M Robertson2, Katherine S Adcock3, Justin T James2, Han S Jeong2, April M Becker4, Mark P Goldberg4, David T Pruitt1,2, Seth A Hays1,2,3, Michael P Kilgard1,2,3, Robert L Rennaker II1,2,3* 1Erik Jonsson School of Engineering and Computer Science, The University of Texas at Dallas, Richardson, United States; 2Texas Biomedical Device Center, Richardson, United States; 3School of Behavioral Brain Sciences, The University of Texas at Dallas, Richardson, United States; 4Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, United States Abstract Recovery from serious neurological injury requires substantial rewiring of neural circuits. Precisely-timed electrical stimulation could be used to restore corrective feedback mechanisms and promote adaptive plasticity after neurological insult, such as spinal cord injury (SCI) or stroke. This study provides the first evidence that closed-loop vagus nerve stimulation (CLV) based on the synaptic eligibility trace leads to dramatic recovery from the most common forms of SCI. The addition of CLV to rehabilitation promoted substantially more recovery of forelimb function compared to rehabilitation alone following chronic unilateral or bilateral cervical SCI in a rat model. Triggering stimulation on the most successful movements is critical to maximize recovery. CLV enhances recovery by strengthening synaptic connectivity from remaining motor *For correspondence: networks to the grasping muscles in the forelimb. The benefits of CLV persist long after the end of [email protected] stimulation because connectivity in critical neural circuits has been restored. -
Spinal Cord, Spinal Nerves, and the Autonomic Nervous System
ighapmLre21pg211_216 5/12/04 2:24 PM Page 211 impos03 302:bjighapmL:ighapmLrevshts:layouts: NAME ___________________________________ LAB TIME/DATE _______________________ REVIEW SHEET Spinal Cord, Spinal Nerves, exercise and the Autonomic Nervous System 21 Anatomy of the Spinal Cord 1. Match the descriptions given below to the proper anatomical term: Key: a. cauda equina b. conus medullaris c. filum terminale d. foramen magnum d 1. most superior boundary of the spinal cord c 2. meningeal extension beyond the spinal cord terminus b 3. spinal cord terminus a 4. collection of spinal nerves traveling in the vertebral canal below the terminus of the spinal cord 2. Match the key letters on the diagram with the following terms. m 1. anterior (ventral) hornn 6. dorsal root of spinal nervec 11. posterior (dorsal) horn k 2. arachnoid materj 7. dura materf 12. spinal nerve a 3. central canalo 8. gray commissure i 13. ventral ramus of spinal nerve h 4. dorsal ramus of spinald 9. lateral horne 14. ventral root of spinal nerve nerve g l 5. dorsal root ganglion 10. pia materb 15. white matter o a b n c m d e l f g k h j i Review Sheet 21 211 ighapmLre21pg211_216 5/12/04 2:24 PM Page 212 impos03 302:bjighapmL:ighapmLrevshts:layouts: 3. Choose the proper answer from the following key to respond to the descriptions relating to spinal cord anatomy. Key: a. afferent b. efferent c. both afferent and efferent d. association d 1. neuron type found in posterior hornb 4. fiber type in ventral root b 2. -
The Nervous System: Sensory and Motor Tracts of the Spinal Cord
15 The Nervous System: Sensory and Motor Tracts of the Spinal Cord PowerPoint® Lecture Presentations prepared by Steven Bassett Southeast Community College Lincoln, Nebraska © 2012 Pearson Education, Inc. Introduction • Millions of sensory neurons are delivering information to the CNS all the time • Millions of motor neurons are causing the body to respond in a variety of ways • Sensory and motor neurons travel by different tracts within the spinal cord © 2012 Pearson Education, Inc. Sensory and Motor Tracts • Communication to and from the brain involves tracts • Ascending tracts are sensory • Deliver information to the brain • Descending tracts are motor • Deliver information to the periphery © 2012 Pearson Education, Inc. Sensory and Motor Tracts • Naming the tracts • If the tract name begins with “spino” (as in spinocerebellar), the tract is a sensory tract delivering information from the spinal cord to the cerebellum (in this case) • If the tract name ends with “spinal” (as in vestibulospinal), the tract is a motor tract that delivers information from the vestibular apparatus (in this case) to the spinal cord © 2012 Pearson Education, Inc. Sensory and Motor Tracts • There are three major sensory tracts • The posterior column tract • The spinothalamic tract • The spinocerebellar tract © 2012 Pearson Education, Inc. Sensory and Motor Tracts • The three major sensory tracts involve chains of neurons • First-order neuron • Delivers sensations to the CNS • The cell body is in the dorsal or cranial root ganglion • Second-order neuron • An interneuron with the cell body in the spinal cord or brain • Third-order neuron • Transmits information from the thalamus to the cerebral cortex © 2012 Pearson Education, Inc.