Neuroanatomy, Cerebellar Dysfunction


Article Author:
Mahmut Unverdi


Article Editor:
Khalid Alsayouri


Editors In Chief:
Kranthi Sitammagari
Mayank Singhal


Managing Editors:
Avais Raja
Orawan Chaigasame
Carrie Smith
Abdul Waheed
Khalid Alsayouri
Trevor Nezwek
Radia Jamil
Patrick Le
Anoosh Zafar Gondal
Saad Nazir
William Gossman
Hassam Zulfiqar
Hussain Sajjad
Steve Bhimji
Muhammad Hashmi
John Shell
Matthew Varacallo
Heba Mahdy
Ahmad Malik
Sarosh Vaqar
Mark Pellegrini
James Hughes
Beata Beatty
Beenish Sohail
Nazia Sadiq
Hajira Basit
Phillip Hynes


Updated:
8/6/2019 9:36:32 AM

Introduction

The cerebellum, meaning "little brain" in Latin, is primarily responsible for the coordination of movement, maintaining posture and balance, muscle tone, and motor learning. Recent research has shown that the cerebellum may also have cognitive functions, but the exact mechanism and pathways are still unclear. In this chapter, we present the gross and functional anatomy of the cerebellum and then focus on the structures that are involved in clinical presentations and syndromes.

Structure and Function

Gross Anatomy

The cerebellum is in the posterior cranial fossa posterior to the brainstem and the fourth ventricle. It is covered by the tentorium cerebelli anteriorly and superiorly. When looking at the cerebellum from behind, it has two hemispheres which are joined together by a longitudinal depression running down the midline of both hemispheres called the vermis. The cerebellar cortical surface is convoluted into numerous folia. The midsagittal view of these folia resembles a branching tree, called the arbor vitae, meaning tree of life in Latin.[1]

When looking at the cerebellum from the side, it's divided into three anatomical lobes, anterior, posterior and flocculonodular lobes, separated by two fissures, the primary and posterolateral fissures. The anterior and posterior lobes are separated from each other by the primary fissure, and the posterolateral fissure separates the posterior and flocculonodular lobe. The flocculonodular lobe lies on the inferior surface of the cerebellum. The cerebellar tonsils are round lobes situated on the undersurface of the cerebellar hemispheres, just inferior to the flocculonodular lobe.[1]

There are four pairs of gray matter nuclei (or deep cerebellar nuclei) in the cerebellum. Starting from the most lateral to the most medial nuclei, they are called dentate, emboliform, globose and fastigial nuclei. Together, the emboliform and globose nuclei have the collective name of the nuclei interpositum.[2] The deep cerebellar nuclei are the primary source of information output from the cerebellum. One exception to this is that the flocculonodular lobe synapses with the vestibular nuclei and these synapses do not pass through the deep cerebellar nuclei before leaving the cerebellum. 

Functionally, the cerebellum divides into three zones, the vestibulocerebellum, cerebrocerebellum, and spinocerebellum (Figure 1).[1]

Vestibulocerebellum

The flocculonodular lobe, also called the vestibulocerebellum, mainly receives input from the ipsilateral vestibular nuclei. It receives additional input from the pretectal area of the midbrain and the visual cortex. Efferents from the flocculonodular lobe relay signals directly to the vestibular nuclei, bypassing the deep cerebellar nuclei. This area is primarily responsible for balance and ocular movements. While the medial part of the flocculonodular lobe (the nodulus) helps maintain balance, the flocculus mediates the vestibulo-ocular adaptation contributing to the smooth pursuit eye movements such as following a slow-moving object with one's eyes. The vestibulo-ocular reflex, a reflex that functions to stabilize the image on the retina during head movement by causing the eyes to move in the opposite direction of the head, is also part of the vestibulo-ocular adaptation.[3]

Spinocerebellum

The spinocerebellum is made up of the vermis (a longitudinal depression in the medial part of the cerebellar hemispheres) and paravermis (intermediate portions of the cerebellar hemispheres; just lateral to the vermis). The spinocerebellum receives somatosensory input from both the ipsilateral face (through the trigeminal nucleus) and body (through the dorsal column of the spinal cord). The primary function of the spinocerebellum is coordination of motor movements and maintenance of muscular tone.

The vermis area coordinates the movements of the central body (e.g., trunk, head, proximal limbs) and the paravermis area coordinates movement from the distal limbs (e.g., arms, legs, fingers, toes). 

The dorsal vermis connects to the fastigial nuclei, both of which modulate saccadic eye movements, (eye movements that rapidly move both eyes from one object to another) and vergence eye movements (moving both eyes away from each other to focus on an image in the distance; opposite of divergence).[4] 

The spinocerebellum has connections to the rubrospinal tract thus modulating muscular tone in the flexor muscles of the body as well as connections to the vestibulospinal tract thus modulating muscular tone in the extensor muscles of the body as well.

Cerebrocerebellum

The cerebellar hemispheres (excluding the vermis and paravermis) are called the cerebrocerebellum. The cerebellar hemispheres function in motor planning, the timing of the onset of movements, and their coordination. Cerebrocerebellum mainly receives input from the primary cerebral motor cortex and the supplementary motor areas via the contralateral corticopontocerebellar fibers. It receives additional input from the contralateral inferior olivary nucleus.

The Purkinje cells send outputs to the dentate and interposed nuclei which project fibers to the contralateral red nucleus (via the cerebellorubral fibers) and ventrolateral thalamic nuclei (via the cerebellothalamic fibers). The ventrolateral thalamic nucleus then relays the signals to the cerebral premotor, and motor cortex and the red nucleus relays the signals to the olivary nuclei. 

The cerebellum is connected to the brainstem by the superior, middle, and inferior peduncles. The largest of the three is the middle peduncle, which contains the pontocerebellar tract. This tract provides afferent information from the contralateral pontine nuclei, which obtain their input from the primary motor cortex and supplementary motor areas. The inferior cerebellar peduncle contains afferent fibers, including dorsal spinocerebellar tract, cuneocerebellar tract, olivocerebellar tract, and vestibulocerebellar tract. The superior cerebellar peduncle conveys efferent information from the deep cerebellar nuclei to the motor nuclei of the thalamus and the red nucleus.

Microstructure

Three layers comprise the cerebellar cortex as opposed to the six layers of the cerebral cortex. These are the granular layer, Purkinje cell layer, and the molecular layer. Purkinje cells provide inhibitory signals to the deep cerebellar nuclei, whereas the deep cerebellar nuclei provide excitatory signals to the efferent nerve fiber tracts.[5]

Embryology

During the third week of embryogenesis, the blastocyst reorganizes into a three-layer structure, a process known as gastrulation. The layers are the endoderm, mesoderm, and ectoderm. The notochord (a transient embryonic structure just below the ectoderm which later becomes the nucleus pulposus of the intervertebral disk in adults) induces the overlying ectoderm to differentiate into the neural plate. The neural plate then gives rise to the neural tube and neural crest cells. The neural tube gives rise to three vesicles, the prosencephalon, mesencephalon, and rhombencephalon, which will ultimately develop into the brain. The prosencephalon gives rise to the telencephalon (which develops into the cerebral hemispheres and lateral ventricles) and the diencephalon (which develops into the thalamus, hypothalamus, and the third ventricle). The mesencephalon develops into the midbrain and aqueduct of Sylvius. The rhombencephalon gives rise to the metencephalon (which develops into the pons, cerebellum and the upper part of the fourth ventricle) and the myelencephalon (which develops into the medulla and lower part of the fourth ventricle). During weeks 7-9, the rhombic lip, which is the posterior section of the metencephalon,

In the first week of the embryo, the epiblast forms the epidermis. The central portion of the epidermis forms the neural plate and into the neural tube. Prosencephalon, mesencephalon, rhombencephalon are formed at week 3. Rhombencephalon becomes metencephalon and myelencephalon. Cerebellum and pons formed from metencephalon. At Week 6, the rudimentary basis of the cerebellum appears near the fourth ventricle. At weeks 7 and 9, the rhombic lip makes its specific movements (protrudes dorsally, bent laterally, extended ventrolaterally and fused with the medially located midbrain) and cerebellar hemispheres starts to form from the primitive choroid plexus in that process. Vermis develops later than hemispheres, possibly from midline dark cell cluster close the aqueduct. At weeks 11 and 12, cerebellar hemispheres become thick as the midbrain. In the midline, fissures of the future vermis are visible. At weeks 16 and 17, vermis becomes as thick as hemispheres and contains deep fissures. The flocculus and nodule can be detected, and inside the cerebellar hemispheres, a pair of primitive dentate nuclei, start appearing.[6]

Blood Supply and Lymphatics

Cerebellum receives its blood supply from the vertebrobasilar system by three pairs of arteries;

Superior Cerebellar Arteries (SCA): These branch off from the lateral sides of the basilar artery and supply the superior part of the cerebellum.

Anterior Inferior Cerebellar Arteries (AICA): These arteries branch off from the lateral sides of the basilar artery just inferior to the posterior cerebral arteries and immediately distal to the convergence of the vertebral arteries. AICA covers the blood supply of the anterior-inferior segment of the cerebellum.

Posterior Inferior Cerebellar Arteries (PICA): Arise from the distal vertebral arteries. The majority of them are intradural. These arteries give branches to supply medulla before reaching to the cerebellum to cover blood supply of posterior cerebellum and inferior cerebellar peduncle. This arrangement explains why the occlusion of PICA results in lateral medullary syndrome (Wallenberg syndrome).

Watershed areas exist between these arteries.[7]

Clinical Significance

Clinical Presentation

Ataxia: Lack of normal coordination of movements.[8]

Gait problems: Lesions of the cerebellum typically affect the same side of the body, and patients fall toward the side of the lesion.

Intention Tremor: Tremor starts when the fine movement starts, especially while reaching the object (cerebellar tremor).[9] The tremor is not present at rest (Parkinsonian tremor).

Dysdiadochokinesia: This is the inability to perform fast, alternating movements.

Decomposition of Movement (abnormal coordination): Movement cannot occur smoothly and gets divided into its components.

Dysmetria: Overshooting or undershooting the target. Patients are unable to reach the target at the first attempt and make corrections.

Dysarthria: This is the inability to articulate words properly.

Signs of Cerebellar Vermis and Flocculonodular Lobe Lesions

Gait Ataxia: Abnormal coordination of movements while walking. Patients have wide-based, drunk like unsteady, stumbling gait, which is also called “staggering gait.” The patient will be unable to walk on toes or heels and in tandem; also known as truncal ataxia.

Titubation: Tremor (noodling) of the head or axial body. If severe, the patient can’t sit or stand without help.

Nystagmus: Commonly bilateral, these are involuntary, rapid, repetitive eye movements, which can be horizontal or vertical.

Signs of Cerebellar Hemisphere (Cerebrocerebellum) Lesions

Limb ataxia: Also referred to as appendicular ataxia. This condition presents with lesions of the intermediate and lateral portions of the cerebellar hemisphere. The degree and locations of ataxia depend on the somatotopic projection of the body parts of the involved cerebellar hemisphere. It can present as dysmetria, dysdiadochokinesis, hypotonia or intention tremor in one or both extremities. Patients can also present with dysarthria.

Developmental Abnormalities

Dandy-Walker syndrome is cerebellar hypoplasia and upward rotation of the cerebellar vermis with cystic dilation of the fourth ventricle.[6]

Joubert Syndrome and rhombencephalosynapsis are rare conditions and seen with cerebellar vermis agenesis.

Pontocerebellar hypoplasias are rare, progressive, familial neurodegenerative disorders, which include PCH gene mutations (tRNA splicing endonuclease subunit genes). There are eleven known subgroups.[10] Signs include cerebellar hypoplasia or atrophy, progressive microcephaly, and different degree of cerebral involvement. 

Medulloblastoma is a common tumor of childhood and roots from embryological cells (granular cells).[11]

Chiari I malformation: This is the caudal location of the cerebellar tonsils. Most of the time, it is asymptomatic. Patients may present with headaches. In severe form Chiari I malformation may cause syringomyelia.


  • Image 11214 Not availableImage 11214 Not available
    Contributed by Mahmut Unverdi, MD
Attributed To: Contributed by Mahmut Unverdi, MD

Interested in Participating?

We are looking for contributors to author, edit, and peer review our vast library of review articles and multiple choice questions. In as little as 2-3 hours you can make a significant contribution to your specialty. In return for a small amount of your time, you will receive free access to all content and you will be published as an author or editor in eBooks, apps, online CME/CE activities, and an online Learning Management System for students, teachers, and program directors that allows access to review materials in over 500 specialties.

Improve Content - Become an Author or Editor

This is an academic project designed to provide inexpensive peer-reviewed Apps, eBooks, and very soon an online CME/CE system to help students identify weaknesses and improve knowledge. We would like you to consider being an author or editor. Please click here to learn more. Thank you for you for your interest, the StatPearls Publishing Editorial Team.

Neuroanatomy, Cerebellar Dysfunction - Questions

Take a quiz of the questions on this article.

Take Quiz
An 80-year-old male patient comes to the clinic with complaints of shaking movements in his hands while reaching an object or trying to drink water. In the physical exam, you found that the patient has overshooting and undershooting an intended action. Which of the following cerebellar nuclei receives input from the most likely injured cerebellar part in this case?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Which is not an adequate statement regarding cerebellar cortex function?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A 60-year-old male presents to the emergency department with sudden onset nausea, vomiting, vertigo, and nystagmus. The patient also complains dysphagia and dysarthria. Physical exam shows respiratory distress, tachycardia, right-sided analgesia of the face, and right-sided constricted pupil, drooping of the upper eyelid and loss of sweating. In addition, the patient cannot abduct his right eye. He is unable to feel pain, hot and cold on the left side of his body and has right-sided limb ataxia. Medical history includes diabetes and hypercholesterolemia. Which of the following arteries is most likely affected in this patient?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A 25-year-old male patient presents to the clinic and complains of breaking objects such as glasses while drinking, unable to drink water properly, shaking movements in his hands while starting the movement, especially while reaching for the object. These shaking movements do not appear at rest. His past medical, surgical, and family history are unremarkable. He is not taking any medications. In the physical exam, finger to nose test is abnormal in addition to abnormal heel to knee test. An MRI shows an abnormality in the cerebellum. Which deep cerebellar nuclei receive input from the most likely injured structure?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A 50-year-old male patient presents to the clinic with his son at post-stroke. His son reports the patient has non-motor cognitive function loss, besides nystagmus. In cognitive tests, even though the Mini-Mental State Exam is normal, executive function loss, linguistic deficits, behavioral changes since the last visit are appreciated. An MRI shows only abnormalities in the cerebellum. A diagnosis of cerebellar cognitive affective syndrome is made. Which of the following deep cerebellar nuclei should receive abnormal input from the cerebellum to cause nystagmus?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A 45-year-old male is brought to the emergency department after passing out. He is taken to the stabilization room and is given glucose without thiamine. He regains consciousness but does not remember what he has been doing in the last few days. During his physical examination, he is stumbling, is unable to walk in a straight line, has a broad-based gait, and visible jerkiness in his eye movements when the head is rotated to sideways. Which of the following areas may be the cause of his symptoms?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A 3-year-old female is brought to the clinic by her parents due to a head-shaking and walking problem. Patient’s prenatal, birth, and postnatal history is unknown because the family has immigrated. Mother complains of the patient’s gait and balance. Per mother, the patient has been unable to catch her peers because she falls while moving. Her big brother has not had any problems while walking at age 2. The patient appears to noodle her head from side to side repeatedly. Physical exam shows horizontal nystagmus in her eyes and a broad-based, unsteady gait. MRI confirms an abnormality in the central nervous system. An in-utero defect is suspected. Which of the following embryological tissue is most likely affected?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up

Neuroanatomy, Cerebellar Dysfunction - References

References

Roostaei T,Nazeri A,Sahraian MA,Minagar A, The human cerebellum: a review of physiologic neuroanatomy. Neurologic clinics. 2014 Nov     [PubMed]
Schmahmann JD, The cerebellum and cognition. Neuroscience letters. 2019 Jan 1     [PubMed]
Ito M, Cerebellar control of the vestibulo-ocular reflex--around the flocculus hypothesis. Annual review of neuroscience. 1982     [PubMed]
Robinson FR,Fuchs AF, The role of the cerebellum in voluntary eye movements. Annual review of neuroscience. 2001     [PubMed]
Voogd J,Glickstein M, The anatomy of the cerebellum. Trends in neurosciences. 1998 Sep     [PubMed]
Butts T,Green MJ,Wingate RJ, Development of the cerebellum: simple steps to make a 'little brain'. Development (Cambridge, England). 2014 Nov     [PubMed]
Savoiardo M,Bracchi M,Passerini A,Visciani A, The vascular territories in the cerebellum and brainstem: CT and MR study. AJNR. American journal of neuroradiology. 1987 Mar-Apr     [PubMed]
Javalkar V,Khan M,Davis DE, Clinical manifestations of cerebellar disease. Neurologic clinics. 2014 Nov     [PubMed]
Puschmann A,Wszolek ZK, Diagnosis and treatment of common forms of tremor. Seminars in neurology. 2011 Feb     [PubMed]
van Dijk T,Baas F,Barth PG,Poll-The BT, What's new in pontocerebellar hypoplasia? An update on genes and subtypes. Orphanet journal of rare diseases. 2018 Jun 15     [PubMed]
Roussel MF,Hatten ME, Cerebellum development and medulloblastoma. Current topics in developmental biology. 2011     [PubMed]
Cho KH,Rodríguez-Vázquez JF,Kim JH,Abe H,Murakami G,Cho BH, Early fetal development of the human cerebellum. Surgical and radiologic anatomy : SRA. 2011 Aug;     [PubMed]

Disclaimer

The intent of StatPearls is to provide practice questions and explanations to assist you in identifying and resolving knowledge deficits. These questions and explanations are not intended to be a source of the knowledge base of all of medicine, nor is it intended to be a board or certification review of PA-Hospital Medicine. The authors or editors do not warrant the information is complete or accurate. The reader is encouraged to verify each answer and explanation in several references. All drug indications and dosages should be verified before administration.

StatPearls offers the most comprehensive database of free multiple-choice questions with explanations and short review chapters ever developed. This system helps physicians, medical students, dentists, nurses, pharmacists, and allied health professionals identify education deficits and learn new concepts. StatPearls is not a board or certification review system for PA-Hospital Medicine, it is a learning system that you can use to help improve your knowledge base of medicine for life-long learning. StatPearls will help you identify your weaknesses so that when you are ready to study for a board or certification exam in PA-Hospital Medicine, you will already be prepared.

Our content is updated continuously through a multi-step peer review process that will help you be prepared and review for a thorough knowledge of PA-Hospital Medicine. When it is time for the PA-Hospital Medicine board and certification exam, you will already be ready. Besides online study quizzes, we also publish our peer-reviewed content in eBooks and mobile Apps. We also offer inexpensive CME/CE, so our content can be used to attain education credits while you study PA-Hospital Medicine.