Cerebellum Flashcards
Name the 3 lobes of the cerebellum
Anterior
Posterior
Floculonodular lobe
What is the function of the penduncles in the cerebellum?
they connect the brainstem to the cerebellum
Identify where the cerebellum is located within the brain.
Dorsal (behind) the brainstem and below the occipital lobe
What is the function of the vermis in the cerebellum?
Divides the 2 cerebral hemispheres (right and left) of the cerebellum.
What are the two fissures of the cerebellum?
Primary (separating anterior and posterior lobes)
Horizontal
Describe where the flocculonodular lobe gets its name.
2 flocculi at either side of the vermis with the nodulus in the centre of the 2 flocculi
Name and describe the peduncles of the cerebellum
Superior cerebellar connects the midbrain to the cerebellum (info leaving cerebellum goes out through the superior peduncle)
Middle cerebellar connects the pons (sensory information coming in) to the cerebellum
Inferior cerebellar connects the medulla to the cerebellum. Is the main sensory input route from the body
Name the 4 deep nuclei of the cerebellum
Denate nuclei, Emboliform nucleus, Globose nucleus (interposed nucleus = emboliform nucleus+globose nucleus), Fastigial nuclei
What is the role of the deep nuclei?
Information relay centres
They receive both excitatory and inhibitory inputs from within the cerebellar cortex
Most output from the cerebellum originate from these nuclei
What is the main role of the cerebellum?
Subconscious control of smooth movement
Ensures movement is coordinated, well timed, spatially coherent and matches the motor plan
How does the cerebellum control smooth movement?
It compares what the motor plan is to what’s happening in the real world in real time
• Detect errors
• Send out corrections
What are afferent tracts?
Name all the afferent tracts of the cerebellum.
Relay incoming info from the body to the cerebellum
- Reticulocerebellar tract
- Corticopontinecerebellar tract
- Vestibulocerebellar tract
- Olivarycerebellar tract
- Anterior spinocerebellar and rostrospinocerebellar tract
- Posterior spinocerebellar and cuneocerebellar tract
Describe the reticulocerebellar tract
Origin: reticular formation and enters the cerebellum Via: superior peduncle
Describe the olivarycerebellar tract
Origin: olivary nuclei
Via: inferior peduncle (medulla)
Function: info related to unexpected movement e.g. loss of balance, reflex activity from spinal cord
Area of cerebellum: spinocerebellum (vermis), cerebrocerebellum (lateral zone)
What 4 tracts give information on where the body is in space? What are the other general functions of these tracts?
Anterior spinocerebellar tract, rostrospinocerebellar tract, posterior spinocerebellar tract and cuneocerebellar tract
They are direct as information comes directly from sensory organs through these tracts to the cerebellum
What peduncle do the anterior spinocerebellar tract, rostrospinocerebellar tract, posterior spinocerebellar tract and cuneocerebellar tract go through to reach the cerebellum?
Anterior spinocerebellar + rostrocerebellar tract go through superior peduncle
Posterior spinocerebellar + cuneocerebellar tract go through the inferior peduncle
Describe the vestibulocerebellar tract
Origin: Vestibular nuclei and (in brainstem)
Via: enters the cerebellum at the inferior peduncle.
Function: Give info on where the head is in relation to space, balance and gravity and influences head and eye movement relative to gaze
Area in cerebellum: goes to flocunodular lobe and vermis
Describe the corticopontinecerebellar tract.
Origin: motor cortex and pontine nuclei
Via: middle peduncle
Relays programming and execution of intended movement
Describe the cuneocerebellar tract
Comes from joint receptors and muscle spindles, reports on position, velocity and force of muscle contraction from the upper limb (via inferior peduncle)
Describe the posterior spinocerebellar tract
Brings subconscious proprioceptive info (from muscles, joints and skin mechanoreceptors) from the lower limb (via inferior peduncle)
Describe the rostrospinocerebellar tract
Brings info from upper limbs about ongoing spinal cord activity (is less specific)
What part of the body does the anterior spinocerebellar relay info from?
Lower limbs
Name all the efferent tracts from the cerebellum (8)
Cerebellothalamocortical tract Globose-emboliform-rubro tract Cerebelloreticular tract Cerebellovestibular tract Vestibulospinal tract Corticospinal tract Reticulospinal tract Rubrospinal tract
Describe the cerebellovesticular tract
Origin: fastigial nucleus
Via: inferior peduncle (as this is shortest path)
Ends: vestibular nuclei
Function: Control eye movement, Contributes to postural control via vestibulospinal tracts
(Goes from cerebellum to vestibular nuclei. Vestibulospinal tract arises from the vestibular nuclei - cerebellum can influence the output of the vestibulospinal tract via the vestibular nuclei)
Describe globose-emboliform-rubro tract
Origin: Interpose nuclei (i.e. globose and emboliform nuclei).
Via: superior peduncle
Ends: red nucleus.
Functions: Influences rubrospinal tract
Describe the cerebellothalamocortical tract
Origin: dentate nucleus
Via: superior peduncle and thalamus
Ends: cortex
Function: Updates output of motor cortex, updates the motor plan, indirectly influences the tract that comes from the cortex (i.e. the corticospinal tract)
Describe the cerebellorecticular tract
Origin: fastigial nucleus
Via: superior peduncle
Ends: reticular formation
Function: Contributes to postural control via reticulospinal tract
(Reticulospinal tract arises form the reticular formation so the cerebellum can indirectly influence the reticulospinal tract)
What nuclei in cerebellum does the cerebellothalamocortical tract leave?
Dentate nuclei
What nuclei in cerebellum does the globose-emboliform-rubro tract leave?
Interpose nuclei (i.e. globose and emboliform nuclei).
What nuclei in cerebellum does the cerebellovestibular tract leave?
All fibres come from fastigal nuclei
What nuclei in cerebellum does the cerebelloreticular tract leave?
Fastigal nucleus. Some fibres come from globose-emboliform-rubro tract
How does the cerebellum influence the corticospinal tracts? What are corticospinal tracts
There are no direct cerebellar-spinal tracts. The cerebellum indirectly influences the corticospinal tract via nuclei of the cerebellum
Tracts that start in the cortex and end in the spinal cord - they influence movement of limbs/trunk
What is the overall function of the
a) lateral pathways
b) medial pathways
a) goal-directed movements
b) basic postural control
Whats another name for the floculonodular lobe?
Vestibulocerebellum
Name the 4 functional regions of the cerebellum
Floculonodular lobe
Medial zone: vermis/spinocerebellum
Intermediate zone: spinocerebellum
Lateral zone: cerebellum
What causes disruption to the cerebellar functioning?
Cerebellar stroke, MS, tumour, head injury, spinocerebellar
conditions, Friedreich’s ataxia
Sensory ataxia
Vestibular ataxia
Define ataxia
Greek for “lack of order” or “disorder”
Causes errors in direction, amplitude, force, Timing, Velocity
What impairments does a disruption in cerebellar functioning cause?
Impairment of afferent input: insufficient data
Impaired processing : within cerebellum
Impairment of efferent output: incomplete output
For what conditions is ataxia an umbrella term?
Dysmetria, dyssynergia, rebound phenomenon, hypotonia, intention tremor, dysdiadochokinesia, dysarthria, nystagmus
Define dysarthria
Disorder of speech articulation
Define nystagmus
Involuntary movement of the eyes, often up and down but also side to side and rarely rotary
Define hypotonia
Reduced resistance to passive movement
Define intention tremor
Oscillation about a joint
• Finger-nose test
• Postural tremor
• Head tremor
Define dysdiadochokinesia
Difficulty with rapid alternating movement
Define dysmetria
Inaccurate amplitude • Misplaced force • Hypermetria • Hypometria
Define dyssynergia
Decomposition of movement
• Errors in the relative timing of segmental components of multi-joint movements
Define rebound phenomenon
lack of check, problems with braking
Name all clinical assessments
Romberg test Rebound test Rapid alternating movement Hell-to-shin test Finger-nose test
Where in the cerebellum is the head and trunk of the somatotopic map located?
Where are the limb representations located?
Vermis
In the intermediate regions (at either side of the vermis)
Describe the inputs/outputs of the floculonodular lobe
Inputs: from the vestibular nuclei
Via: vestibulocerebellar tract
Function: where the head is in space (as the head of the homunculus is here)
