Cerebellum

Front 1

General function?

Back 1

Tone, Posture + balance, Co-ordination of movement

Front 2

Correlate the function to each area

Back 2

Tone= spinocerebellar= anterior lobe (paleocerebellum)

Balance= Vestibulocerebellar= Flocculonodular lobe (archicerebellum)

Coordination= Cerebrocerebellar = posterior lobe (neocerebellum)

Front 3

What is the Vermis and paravermis function?

Back 3

Vermis and paravermis involved in the spinocerebllum tract
Vermis represents the head neck and trunk
Paravermis represents the limbs
Tonotopically organised!

Front 4

I am picking up a cup of tea... what does the cerebellum do?

Back 4

Cerebellum firing before movement starts
Compares the Intended movement from the cortex with the actual movement from the muscle
Sends the comparison back to the cortex and the cortex adjusts the movement accordingly

Front 5

How does the cerebellum know what the muscles are doing?

Back 5

Stretch receptors, golgi tendon organs and other sensory receptors detect movement and send sensory info to the spine.... SPINOCEREBELLAR TRACT
Spinocerebellar tract= dorsospino cerebellar tract (clarke's nucleus) through the inferior cerebellar peduncle to the vermis (axial) and paravermis (distal limbs)
OR cuneospino cerebellar tract (paracuneate nucleus) from upper limbs
OR ventrspino cerebellar tract from head and neck (through superior cerebellar peduncle)

Front 6

What nuclei are involved with the spinocerebellar tract?

Back 6

Emboliform nucleus and globus nucleus (together make the interposed nuclei)

Front 7

When the fibres enter through the inferior cerebellar peduncle what type are they?

Back 7

MOSSY fibres

Front 8

What happens in the cerebellum when the fibers enter?

Back 8

Mossy fibres branch to the interposed nuclei and excite! (glutamate)
The mossy fibre synapses on the granule cell in the granule layer
Fibres from the granule cell extend up into the outer cortex layer and BIFURCATE
They become parallel fibres.
Each mossy fiber can synapse with millions of purkije fibers in the purkinje layer
They stimulate the purkinje cells which in turn inhibit the interposed nuclei

Front 9

Where do the fibers go when they leave the cerebellum (spinocerebellum)?

Back 9

Cerebellar rubro tract to red nucleus to thalamus OR cerebellothalamic tract (direct) to ventro medial and lateral nuclei. Thalamus to cortext for modification.
Some rubrospinal fibres from the red nucleus down

Front 10

How does the cerebellum receive information from the vestibulospinal tract?

Back 10

The vestibule of the ear contains the utricle and the saccule (otilith organs) which are in the sensory epithelium. (static movement)
Send signals to the vestibular nerve which travels to the cerebellum through the inferior cerebellar peduncle
Nucleus involved= Fastidual

Front 11

Where do the fibres go when leaving the cerebellum?

Back 11

Cerebellar vestibulo fibers stimulate the vestibular nuclear complex
Down= vestibulo spinal tract= Anti gravity/ extensor muscles for balance!
Some synapse at the reticular nuclei and descend as reticulospinal tract
Up= Fibers within the medical longitudinal fasciclus stimulate CN 3/4/6 nuclei for extra occular movements to coordinate with head movement

Front 12

What enters the middle cerebellar peduncle?

Back 12

Fibres from the cortex enter the pons to the pontine nuclei (corticopontine fibers)
From here fibres enter the middle cerebellar peduncle
This is the main pathway in which the cortex communicates with the cerebellum (Cortico pontine cerebellar pathway)
They enter the cerebrocerebellum where they synapse at the dentate nucleus
They then leave as dento- rubral OR dento- thalamic fibres to the cortex
This is for PLANNING MOVEMENT!

Front 13

What other fibers enter the cerebellum which are NOT Mossy fibers?

Back 13

Climbing fibres from the inferior olivary nucleus. Remember the Spartans! The spartan climbed the olive tree to the outer layer of cortex and released Aspartate!
Aspartate excites purkinje cells (1:1 ratio) which in turn inhibit the deep cerebellar nuclei

Front 14

What are the mechanisms of information control?

Back 14

Golgi cells in granule layer
Stellate cells
Basket cells

Front 15

How do these mechanisms work?

Back 15

Golgi cells are excited by granule cells (glutamate). The golgi cell then auto inhibits the granule cell by releasing GABA
Mossy fibres can also stimulate golgi cells directly to inhibit the granule cell
This is to prevent over stimulation
Parallel fibres stimulate stellate and basket fibres which inhibit neighbouring purkinje cells (GABA) and therefore focus a response

Front 16

What affects the vermis quickly?

Back 16

Alcohol
Results in little co ordination and no balance!

Front 17

What happens if there is cerebellar damage?

Back 17

VANISHED
V = Vertigo
A = Ataxia
N = Nystagmus
I = Intention tremor
S = Slurred speech
H = Hypotonic reflexes
E = Exaggerated broad based gait
D = Dysdiodochokinesia