L18 Cerebellum: Motor Control/Disease Flashcards
Vestibulocerebellum Afferents and Efferents
2 Afferents from Vestibular System=> Flocculonodular Lobe:
- Afferents from Vestibular Nucleus => IPSILATERAL Cerebellum via Inferior Peduncle => FLOCCULUS (Lateral) as Mossy Fiber Inputs
- Direct Input from Vestibular Nerve (ONLY first-order axons w/ direct access to the cerebellar cortex!!) => NODULUS (Center) + VERMIS
Efferents*:
- Minority of Flocculonodular Purkinje Axons project to Fastigial Nucleus => Axial Muscle Control
- Majority project to Vestibular Nucleus via INFERIOR PEDUNCLE (bypassing deep cerebellar nucelli) => Eye Movement Control
ONLY first-order axons w/ direct access to the cerebellar cortex?
Flocculonodular Lobe receives direct Input from Vestibular Nerve**
=> NODULUS (Center) + VERMIS
Errors of the Vestibulo-Occular Reflex?
Retinal Slip
Vestibulo-Ocular Reflex
3 Afferent Tracts of the Spinocerebellum
Posterior Spinocerebellar Trac (PSC): Legs and lower trunk
Cuneocerebellar Tract (CC): Arms and upper trunk
Anterior Spinocerebellar Tract
Posterior Spinocerebellar Tract (PSC):
- 1a afferents enter the cord and synapse on _____________________
- 2º ascend ipsilaterally and enter the cerebellum by the _____________ Peduncle (Mossy Fibres)
- Information Relayed?
Posterior Spinocerebellar Tract (PSC):
- 1a afferents enter cord and synapse on Clarke’s nucleus.
- 2º ascend ipsilaterally and enter the cerebellum by the INFERIOR PEDUNCLE (Mossy Fibres)
- Relays information about muscle and joint position/movement (Legs and lower trunk) to the cerebellum
Cuneocerebellar Tract (CC):
- 1a axons traveling through the ________________synapse in _________________.
- 2º ascend ipsilaterally and enter the cerebellum by the _____________ Peduncle (Mossy Fibres)
- Information Relayed?
Cuneocerebellar Tract (CC):
- 1a axons traveling through the Fasciculus Cuneatus synapse in Accessory Cuneate Nucleus.
- 2º ascend ipsilaterally and enter the cerebellum by the INFERIOR PEDUNCLE (Mossy Fibres)
- Relays information about muscle and joint position/movement (Arms and Upper Trunk) to the cerebellum
Anterior Spinocerebellar Tract
- Tract originates in ____________________________
- Fibres cross the cord and ascend in the anterior spinocerebellar tract to the ______________________
- Enter the cerebellum through _____________________ after which they Cross again in _______________
Anterior Spinocerebellar Tract
- Tract originates in the motor region of grey matter
- Fibres cross the cord and ascend in the anterior spinocerebellar tract to the Lower Midbrain
- Enter the cerebellum through SUPERIOR PEDUNCLE after which they Cross again in cerebellum
- While the spinal tract is contralateral, fibers end up on the same side as they originate.
In the Spinocerebellum Purkinje axons from_________ synapse in ________________ Nucleus then:
=> Thalamus: _________________ via __________ PEDUNCLE => _______________________________________
=> Brainstem: __________________ and ______________ via INFERIOR _____________________
Gives rise to ___________________ and ____________________ Tracts => strong effects on muscle tone
In the Spinocerebellum Purkinje axons from Vermis synapse in Fastigial Nucleus then:
=> Thalamus: Ventrolateral Nucleus via SUPERIOR PEDUNCLE => IPSILATERAL Motor Cortex
=> Brainstem: Medullary Reticular Formation and Lateral Vestibular Nucleus via INFERIOR PEDUNCLE
Gives rise to Lateral Vestibulospinal and Reticulospinal Tracts => strong effects on muscle tone
Cerebrocerebellum receives input from Cortex via ___________________
Purkinje fibers project to_______________ => ____________ PEDUNCLE
Project to _______LATERAL ________________________ of Thalamus.
Cerebrocerebellum receives input from Cortex via Pontine Nuclei
Purkinje fibers project to Dentate Nucleus => SUPERIOR PEDUNCLE
Project to CONTRALATERAL Ventrolateral Nucleus of Thalamus.
2 Circuits of the Cerebrocerebellum
- Sensory/Association Cortex: Pathway?
- Motor Cortex and Red Nucleus: Pathway?
- Sensory and Association Cortex: Pontine Nucleus => Cerebrocerebellum => Thalamus => Motor Cortex
- Motor Cortex and Red Nucleus: Inferior Olive (Motor Learning: Climbing fibers change strength of synaptic connection) =>Cerebrocerebellum => Red Nucleus/Motor Cortex
Pathway Involved in Motor Learning/Procedural Memory?
Motor Cortex and Red Nucleus: Inferior Olive (Motor Learning: Climbing fibers change strength of synaptic connection) =>Cerebrocerebellum => Red Nucleus/Motor Cortex
Various Types of Ataxia?
_________________________
□ Wide based gait
□ Uneven steps, lateral movement
□ ___________________ (Error in judgment of the passage of time)
□ Associated with SCA1. Subsequent genes named SCA2, SCA3 etc
□ Many forms are polyglutamine (CAG) repeats (Severity depends on number of repeats)
Spinocerebellar Ataxia
□ Wide based gait
□ Uneven steps, lateral movement
□ Dyschronometria (Error in judgement of the passage of time)
□ Associated with SCA1. Subsequent genes named SCA2, SCA3 etc
□ Many forms are polyglutamine (CAG) repeats (Severity depends on number of repeats)
____________________________
□ Intention Tremor
□ Handwriting Abnormalities
□ ______________ (Slurring, Irregular Rhythm)
□ ______________ (Error in judgement of the passage of time)
Cerebrocerebellar Ataxia
□ Intention Tremor
□ Handwriting Abnormalities
□ Dysarthria (Slurring, Irregular Rhythm)
□ Dyschronometria (Error in judgement of the passage of time)
____________________
□ Postural Instability
□ Negative _______________ (Uncorrected by visual input- Visual input cannot be integrated)
Vestibulocerebellar Ataxia
□ Postural Instability
□ Negative Romberg’s Test (Uncorrected by visual input- Visual input cannot be integrated)
_________________________
□ Wide based gait
□ Uneven steps, lateral movement
□ ___________________ (Error in judgment of the passage of time)
□ Associated with SCA1. Subsequent genes named SCA2, SCA3 etc
□ Many forms are ______________ repeats (Severity depends on number of repeats)
Spinocerebellar Ataxia
□ Wide-based gait
□ Uneven steps, lateral movement
□ Dyschronometria (Error in judgement of the passage of time)
□ Associated with SCA1. Subsequent genes named SCA2, SCA3 etc
□ Many forms are ______________repeats (Severity depends on number of repeats)
Purkinje Cell’s function in controlling motion?
_______________________: Impairment of movements exibiting a rapid change in motion. Caused by a failure to switch on/off antagonizing muscle groups?
Damage to which part of the Brain is this characteristic of?
Dysdiadochokinesia: Impairment of movements exibiting a rapid change in motion. Caused by a failure to switch on/off antagonizing muscle groups.
Characteristic of damage to LATERAL CEREBELLUM
______________________: Difficulty in judging scale
Dysmetria: Difficulty in judging scale:
- Hypermetria: Movements overshoot
- Hypometria: Movements undershoot
_________________:
- When lost as an adult is catastrophic
- When lost congenitally, cortex takes over limiting ataxia => better with age
Cerebellar Agenesis:
- When lost as an adult is catastrophic
- When lost congenitally, cortex takes over limiting ataxia => better with age
Olivopontocerebellar Atrophy:
□ ___________ (alpha-synuclein abnormalities) and _______ (RARE) forms
□ White matter loss (LOSS OF ______, NOT ______)
□ Purkinje cell loss
□ Loss of _______________ => Parkinsonian Gait occasionally
□ _________ (pain while swallowing) and ________ (Speech disorder)
□ _________ (sudden, unintended, and uncontrollable jerky movements of the arms, legs, and facial muscles)
□ _______ (Slow writing of hands and feet)
□_________________=> Hyperactive tendon reflexes
Olivopontocerebellar Atrophy
□ Sporadic(alpha-synuclein abnormalities) and Inherited (RARE) forms
□ White matter loss (LOSS OF AXON, NOT MYELIN)
□ Purkinje cell loss
□ Loss in substantia nigra => Parkinsonian Gait occasionally
□ Dysphagia (pain while swallowing) and Dysarthria (Speech disorder)
□ Chorea (sudden, unintended, and uncontrollable jerky movements of the arms, legs, and facial muscles)
□ Atheosis (Slow writing of hands and feet)
□ Pyramidal Tract Dysfunction=> Hyperactive tendon reflexes
_________________________________________:
□ Results from Thiamine (Vitamin B1) Deficiency => Loss/Shrinkage of _____________
□ Thalamus and ____________ Affected
□ Seen in conjunction with __________________ (anterograde and retrograde amnesia, confabulation)
Symptoms?
Wernicke’s Encephalopathy
□ Results from Thiamine (Vitamin B1) Deficiency => Loss/Shrinkage of Purkinje Cells
- Associated with chronic alcohol abuse (Alchohol inhibits intestinal absorption of thiamine) and HIV
□ Thalamus and Raphe Nucleus Affected
□ Seen in conjunction with Korsakoff’s Syndrome (anterograde and retrograde amnesia, confabulation)
Symptoms:
- Nystagmus (vestibulocerebellum)
- Anisocoria (unequal pupil size)
- Ophthalmoplegia
- Conjugate gaze palsies
- Confusion
- Gait ataxia
