Exam #2: Cerebellum Flashcards
How do you know the difference between tremor that is Basal Ganglia in origin or Cerebellum in origin?
Basal Ganglia= tremor AT REST
Cerebellum= tremor WITH MOVEMENT
What is the function of the cerebellum?
1) Coordination of motor movement
2) Procedural memory
Specifically, what are the aspects of motor functions that are coordinated by the cerebellum?
- Velocity
- Force
- Duration
- Timing
- Trajectory
What is the structure that goes between the two cerebellar hemispheres?
Vermis
What is the floculaonodular lobe?
This is a bilateral structure on the ventral surface of the cerebellum & vermis that connects to the vestibular system
- Flocculus= cerebellum
- Nodulus= vermis
What is the function of the floculonodular lobe?
Balance
**Note that this is also called the vestibulocerebellar lobe
What is the spinocerebellum?
This is the “paravermal” area that receives input from the spinal cord– maintains muscle tone & adjusts movements of the axial trunk/ proximal limbs
*****“Reciprocally connected to the spinal cord”
What is the cerebrocerebellum?
Lateral areas of the cerebellum that receives information from the cerebral cortex; functions in precise control of executed movements
*****“Reciprocally connected to the cerebral cortex”
How is the “homoculus” of the cerebellum organized?
There are 2x homunculi:
1) Anterior= head is posterior & feet are anterior
- ONE homunculus
2) Posterior= head is anterior & LE are posterior
- TWO homunculi
**Both are oriented in a medial to lateral fashion; axial & proximal limb medial; distal limbs lateral
Name the deep cerebellar nuclei from medial to lateral.
- Fastigial nucleus (midline)
- Globose nucleus
- Emboliform nucleus
- Dentate nucleus
**Note that these are listed from medial to lateral
What are the interposed nuclei?
Globose & emboliform nuceli together
What cerebellar cortical zone is associated with the spinocerebellar tract?
Vermis
Paravermal
What nuclei are associated with the spinocerebellar tract?
Fastigial nuclei
Interposed nuceli
What cerebellar cortical zone is associated with the cerebrocerebellar tract?
Hemispheric (cerebellar)
What nuclei are associated with the cerebrocerebellar tract?
Dentate nuclei
What cerebellar cortical zone is associated with the vestibulocerebellar tract?
Flocculonodular lobe
What nuclei are associated with the vestibulocerebellar tract?
Vestibular nuceli
*****I.e. Floculonodular lobe DOES NOT synapse with the deep cerebellar nuclei
What information does the cerebellum need to function? Where does the cerebellum receive that information from?
- Cerebral cortex needs to send the “instructions” to the cerebellum via the “CORTICOPONTO-CEREBELLAR” tract
- Proprioceptive information about the “current state” of the body from the “SPINOCEREBELLAR TRACT”
- Cerebellum needs to send information BACK to the cortex; occurs via the “DENTORUBROTHALAMIC” tract
What is the function of the dentorubrothalamic tract?
Sends information back up to the thalamus after the execution of an action
What tract is associated with the inferior peduncle?
Spinocerebellar
*Current state of the body
What tract is associated with the middle peduncle?
Corticoponto-cerebellar
*Instructions from the cortex
What tract is associated with the superior peduncle?
Dentorubrothalamic
*Information from the cerebellum back to the cortex
What are the two basic functions of the vestibulocerebellum?
1) Balance & equilibrium
2) Coordination of eye & head movements
Where does the input of the vestibulocerebellum come from?
Vestibular system
*Inferior Olivary Nucleus
Where does the vestibulocerebellum send output to?
1) Vestibular nuclei
2) Vestibulospinal tracts
3) Medial longitudinal fasiculus
What cranial nerves does the Medial Longitudinal Fasciulus connect?
CN:
- III
- IV
- VI
What are the two major functions of the spinocerebellum?
1) Adjust movement based on proprioception
2) Posture & muscle tone
Where does the input to the spinocerebellum come from?
- Dorsal & ventral spinocerebellar tracts
- Cuneocerebellar tract
- Trigeminocerebellar tract
What is the output of the spinocerebellum?
- Vestibulospinal tract
- Reticulospinal tract
What are the general functions of the cerebrocerebellum?
1) Preparation
2) Fine coordination of motor commands w/ sensory input–especially the arm & hand
Where does the input to the cerebrocerebellum come from?
- Corticopontocerebellar tract
- Olivocerebellar tract
What is the output of the cerebrocerebellum?
- Dentorubrothalamic tract
- Rubrospinal tract
What are the three cortical layers of the cerebellum?
- Molcular
- Purkinje
- Granular
Draw the schematic of the cerebellar layers.
N/A
What is the function of the inferior olivary nucleus?
Procedural learning
- Reinforcing motor skills
- Practice makes perfect
What is the Cortico-olivocerebellar pathway?
Input from the inferior olivary nucleus to ?????
What aspects of the basal ganglia and cerebellum are alike?
1) Both influence motor movement
2) Both modifty or adjust motor commands
3) NO PARALYSIS W? LESION
Generally, how do the Basal Ganglia and Cerebellum differ?
Basal Ganglia= Permissive
Cerebellum= Execution
Define ataxia.
Lack of coordination of movement
Define dysmetria.
Individual that is unable to estimate the distance between the moving body part & target
**Also called “past-pointing”
Define dysdiadochokinesia.
Inability to carry out rapid alternating movements
Define nystagmus.
Rhythmic oscillation of one or both eyes
In patients with a cerebellar stroke, which side of the body will symptoms manifest? How does this differ from other brain lesions?
IPSILATERAL
What are the manifestations of a cerebellar infarct?
Ataxia
Dysmetria (past-pointing) of limb
Ocular dysfunction/ nystagmus/ diplopia
Vertigo
What artery is typically occluded in cases of a cerebellar infarct?
PICA (Posterior Inferior Cerebellar Artery)
