Neurology Motor Neurone Tracts & Posturing

Total Page：16

File Type：pdf, Size：1020Kb

NEUROLOGY MOTOR NEURONE TRACTS & POSTURING Upper motor neurones originate at either the motor cortex or brainstem nuclei. They travel, via the brainstem and spinal cord to the anterior horn of their target spinal level where they synapse with a target lower motor neurone This continues the motor signal to the target muscle group leading to voluntary movement Upper motor neurone tracts are divided anatomically into pyramidal and extrapyramidal tracts based on whether they pass through the “pyramids” of the medulla Pyramidal tracts are: o Corticospinal- main motor tracts to most of the body, 90% of neurons, which control limb and fine motor movement, cross over at the medulla o Corticobulbar- controls non- oculomotor cranial nerve motor functions. Most CN get bilateral UMN innervation, except for lower branches of CN VII & CN XII. Extrapyramidal tracts include: rubrospinal tract upper limb flexors medial reticulospinal tract upper limb flexors lateral reticulospinal tract upper limb extensors vestibulospinal tract posture and lower limb extensors tectospinal tract coordinates reflex head/ eye movements CMP 6 HMP 5 Kevin Gervin 7/2/17 “POSTURING” Decorticate posturing is caused by a lesion above the red nucleus. Rubrospinal tract starts at the red nucleus (rubro) & terminates in the cervical spine, it facilitates upper limb flexion Lesion above the red nucleus removes inhibition of rubrospinal tract overcoming upper limb extensors Lesion of corticospinal tract causes unopposed vestibulospinal (leg extension) action Decerebrate posturing is caused by a lesion below the red nucleus No rubrospinal action so unopposed lateral reticulospinal tract action Lesion of corticospinal tract causes unopposed vestibulospinal (leg extension) action Decerebrate posturing is commonly seen in pontine strokes Progression of decorticate to decrebrate posturing is ominous or indicative for uncal (transtentoral) or tonsillar brain herniation CMP 6 HMP 5 Kevin Gervin 7/2/17 .

Copy Link

Recommended publications

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.
[Show full text]
Magnetic Resonance Imaging Techniques for Visualization of the Subthalamic Nucleus
J Neurosurg 115:971–984, 2011 Magnetic resonance imaging techniques for visualization of the subthalamic nucleus A review ELLEN J. L. BRUNENbeRG, M.SC.,1 BRAM PLATEL, PH.D.,2 PAUL A. M. HOFMAN, PH.D., M.D.,3 BART M. TER HAAR ROmeNY, PH.D.,1,4 AND VeeRLE VIsseR-VANdeWALLE, PH.D., M.D.5,6 1Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven; Departments of 3Radiology, 4Biomedical Engineering, and 5Neurosurgery, and 6Maastricht Institute for Neuromodulative Development, Maastricht University Medical Center, Maastricht, The Netherlands; and 2Fraunhofer MEVIS, Bremen, Germany The authors reviewed 70 publications on MR imaging–based targeting techniques for identifying the subtha- lamic nucleus (STN) for deep brain stimulation in patients with Parkinson disease. Of these 70 publications, 33 presented quantitatively validated results. There is still no consensus on which targeting technique to use for surgery planning; methods vary greatly between centers. Some groups apply indirect methods involving anatomical landmarks, or atlases incorporating ana- tomical or functional data. Others perform direct visualization on MR imaging, using T2-weighted spin echo or inver- sion recovery protocols. The combined studies do not offer a straightforward conclusion on the best targeting protocol. Indirect methods are not patient specific, leading to varying results between cases. On the other hand, direct targeting on MR imaging suffers from lack of contrast within the subthalamic region, resulting in a poor delineation of the STN. These defi- ciencies result in a need for intraoperative adaptation of the original target based on test stimulation with or without microelectrode recording. It is expected that future advances in MR imaging technology will lead to improvements in direct targeting.
[Show full text]
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
[Show full text]
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.
[Show full text]
Auditory and Vestibular Systems Objective • to Learn the Functional
Auditory and Vestibular Systems Objective • To learn the functional organization of the auditory and vestibular systems • To understand how one can use changes in auditory function following injury to localize the site of a lesion • To begin to learn the vestibular pathways, as a prelude to studying motor pathways controlling balance in a later lab. Ch 7 Key Figs: 7-1; 7-2; 7-4; 7-5 Clinical Case #2 Hearing loss and dizziness; CC4-1 Self evaluation • Be able to identify all structures listed in key terms and describe briefly their principal functions • Use neuroanatomy on the web to test your understanding ************************************************************************************** List of media F-5 Vestibular efferent connections The first order neurons of the vestibular system are bipolar cells whose cell bodies are located in the vestibular ganglion in the internal ear (NTA Fig. 7-3). The distal processes of these cells contact the receptor hair cells located within the ampulae of the semicircular canals and the utricle and saccule. The central processes of the bipolar cells constitute the vestibular portion of the vestibulocochlear (VIIIth cranial) nerve. Most of these primary vestibular afferents enter the ipsilateral brain stem inferior to the inferior cerebellar peduncle to terminate in the vestibular nuclear complex, which is located in the medulla and caudal pons. The vestibular nuclear complex (NTA Figs, 7-2, 7-3), which lies in the floor of the fourth ventricle, contains four nuclei: 1) the superior vestibular nucleus; 2) the inferior vestibular nucleus; 3) the lateral vestibular nucleus; and 4) the medial vestibular nucleus. Vestibular nuclei give rise to secondary fibers that project to the cerebellum, certain motor cranial nerve nuclei, the reticular formation, all spinal levels, and the thalamus.
[Show full text]
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 ..............................................................................................................................................
[Show full text]
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
[Show full text]
Hypertrophic Olivary Degeneration Secondary to Traumatic Brain Injury: a Unique Form of Trans-Synaptic Degeneration Raman Mehrzad,1 Michael G Ho2
… Images in BMJ Case Reports: first published as 10.1136/bcr-2015-210334 on 2 July 2015. Downloaded from Hypertrophic olivary degeneration secondary to traumatic brain injury: a unique form of trans-synaptic degeneration Raman Mehrzad,1 Michael G Ho2 1Department of Medicine, DESCRIPTION haemorrhagic left superior cerebellar peduncle, all Steward Carney Hospital, Tufts A 33-year-old man with a history of traumatic brain consistent with his prior TBI. Moreover, the right University School of Medicine, Boston, Massachusetts, USA injury (TBI) from a few years prior, secondary to a inferior olivary nucleus was enlarged, which is 2Department of Neurology, high-speed motor vehicle accident, presented with exemplified in unilateral right hypertrophic olivary Steward Carney Hospital, Tufts worsening right-sided motor function. Brain MRI degeneration (HOD), likely secondary to the haem- University School of Medicine, showed diffuse axonal injury, punctuate microbleed- orrhagic lesion within the left superior cerebellar Boston, Massachusetts, USA ings, asymmetric Wallerian degeneration along the peduncle, causing secondary degeneration of the fi – Correspondence to left corticospinal tract in the brainstem and contralateral corticospinal tracts ( gures 1 6). Dr Raman Mehrzad, [email protected] Accepted 11 June 2015 http://casereports.bmj.com/ fl Figure 3 Brain axial gradient echo MRI showing Figure 1 Brain axial uid-attenuated inversion recovery haemosiderin products in the left superior cerebellar MRI showing hypertrophy of the right inferior olivary peduncle. nucleus. on 25 September 2021 by guest. Protected copyright. To cite: Mehrzad R, Ho MG. BMJ Case Rep Published online: [please include Day Month Year] Figure 2 Brain axial T2 MRI showing increased T2 Figure 4 Brain axial gradient echo MRI showing doi:10.1136/bcr-2015- signal change and hypertrophy of the right inferior evidence of haemosiderin products in the left>right 210334 olivary nucleus.
[Show full text]
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.
[Show full text]
Metabolic Activity of Red Nucleus and Its Correlation with Cerebral Cortex and Cerebellum: a Study Using a High-Resolution Semiconductor PET System
Metabolic Activity of Red Nucleus and Its Correlation with Cerebral Cortex and Cerebellum: A Study Using a High-Resolution Semiconductor PET System Kenji Hirata1,2, Naoya Hattori3, Wataru Takeuchi4, Tohru Shiga1, Yuichi Morimoto4, Kikuo Umegaki5, Kentaro Kobayashi1, Osamu Manabe1, Shozo Okamoto1, and Nagara Tamaki1 1Department of Nuclear Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan; 2Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, California; 3Department of Molecular Imaging, Hokkaido University Graduate School of Medicine, Sapporo, Japan; 4Research and Development Group, Hitachi Ltd., Tokyo, Japan; and 5Division of Quantum Science and Engineering, Faculty of Engineering, Hokkaido University, Sapporo, Japan (1). The rubrospinal tract mainly controls limb musculature, whereas The red nucleus (RN) is a pair of small gray matter structures located the pyramidal tract can act on the whole musculature (1). A recent in the midbrain and involved in muscle movement and cognitive anatomic study indicated that a signiﬁcant amount of rubrospinal tract functions. This retrospective study aimed to investigate the metabo- is present in the human brain (2). Because neuronal activity of the RN lism of human RN and its correlation to other brain regions. Methods: in Parkinson disease is known to be increased during passive and We developed a high-resolution semiconductor PET system to image voluntary movements (3), the RN may play a role in the coordination small brain structures. Twenty patients without neurologic disorders of muscular movement. Cognitive symptoms, such as intellectual underwent whole-brain scanning after injection of 400 MBq of fatigability, decreased verbal ﬂuency, and discrete memory impair- 18F-FDG.
[Show full text]
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.
[Show full text]
6.25 Fish Vestibulospinal Circuits Vfinal
Cover Page Title Vestibulospinal circuits and the development of balance in fish Authors Yunlu Zhu, Kyla R. Hamling, David Schoppik Affiliation Department of Otolaryngology, Department of Neuroscience & Physiology, and the Neuroscience Institute, New York University School of Medicine, New York, United States; Contact Information Yunlu Zhu Address: 435 E 30th st, Rm 1145R, New York, NY 10016, United States. Email: [email protected] Phone: 434-242-7311 Kyla R. Hamling Address: 435 E 30th st, Rm 1138, New York, NY 10016, United States. Email: [email protected] Phone: 707-853-7689 David Schoppik Address: 435 E 30th st, Rm 1103, New York, NY 10016, United States. Email: [email protected] Phone: 646-501-4555 Keywords Balance; Hindbrain; Inner ear; Lamprey; Locomotion; Magnocellular; Neural circuit; Octavomotor; Otolith; Teleost; Vestibular; Vestibulospinal; Zebrafish Synopsis The ability to maintain balance and adjust posture through reflexive motor control is vital for animal locomotion. The vestibulospinal nucleus residing in the hindbrain is responsible for relaying inner ear vestibular information to spinal motoneurons and is remarkably conserved from fish to higher vertebrates. Taking the advantage of relatively simple body plan and locomotor behavior, studies in fish have significantly contributed to our understanding of the of the anatomy, connectivity, and function of the vestibulospinal circuits and the development of balance control. Abstract During locomotion, animals engage reflexive motor control to adjust posture and maintain balance. The vestibulospinal nucleus responsible for transmitting vestibular information to the spinal cord is vital for corrective postural adjustments and is remarkably conserved from fish to higher vertebrates. However, little is known about how the vestibulospinal circuitry contributes to balance control.
[Show full text]