Cerebellum

What does the cerebellum do?

• maintains equilibrium, coordinates muscle contractions

• synergy of muscle action

• timing of muscle contraction and appropriate force

What is ataxia

Lack of coordination, wide unsteady gait

Dysdiadochokinesia

inability to perform rapid and coordinated movements smoothly

what are folia similar in structure to?

gyrus

what is the purpose of folia?

timing and coordination for spacial awareness

Where are purkinje cells located in the cerebellum?

between the dense (dark grey) and less dense (light grey) neurons

what is contained in a folia

neurons and axons

is damage to the cortex more or less problematic

less

What are the 4 deep cerebellar nuclei?

emboliform, dentate, globose,

What info does the pontocerebellar tract carry?

motor info about what you are about to do

what is the region near the midline know as?

vermis

which part of the vermin is demylinated?

inferior vermis

what separates the main cerebellar lobe from the focculonodular lobe?

posterolateral fissure

how much of the cortical surface is concealed in the intervening sulci?

85%

how large is the cortical area compared to the cerebral cortex?

about ¾ the size

What are the 3 layers of the cerebellar cortex?

molecular layer

purkinje layer

granule layer

Which layer of the cerebellar cortex is mainly axons and small cells?

modular layer

Which layer of the cerebellar cortex is a single layer of cells?

purkinje layer

Which layer is the most cell dense layer of the cerebellar cortex?

granular layer

What cells are in the granular cell layer?

granular cells (excitatory) and golgi cells (inhibitory)

What cells are found in the molecular cell layer?

basket cells and stellate cells

what neurotransmitter is associated with purkinje cells?

GABA (inhibitory)

what is the ONLY excitatory cell?

granular cells

What are granular cell axons known as?

parallel fibers (telephone pole wire)

How do purkinje cells have their dendritic arbor run compared to the folium?

Perpendicular 

What is the neurotransmitter for granule cells?

Glutamate

What fibers excite deep cerebellar nuclei then excite a purkinje cell?

Climbing fibers

What fibers will stimulate the deep cerebellar nuclei then excite granular cells?

Mossy fibers

What information do climbing fibers carry?

Motor info

What cell has axons that leave the cortex?

Purkinje cells

What is the one exception of fibers that leave the cortex to go to the brainstem?

Vestibular nuclei

Where do climbing fibers originate from?

Inferior olivary complex

Where do mossy fibers synapse?

Glomerulus

What do both the mossy fibers and climbing fibers send collateral fibers to?

Central cerebellar nucleus

What are the 4 nuclei of the deep cerebellar matter?

Fastigial, globose, emboliform, dentate

What tracts contain extrinsic input to the cerebellum?

Pontocerebellar, spinocerebellar, olivocerebellar

Crudely processed information in the central nuclei is refined by _____ signals received by the cortex

Inhibitory

The combination of the two inputs maintains a ______ discharge from the central nuclei to the brainstem and thalamus

Tonic

What neurotransmitters relay all information to the deep nuclei via excitation?

Aspartate and glutamate

What are the inferior peduncle cerebellar afferents?

• Olivocerebellar fibers,

• dorsal spinocerebellar tract,

• cuneocerebellar tract,

• vestibulocerebellar fibers,

• trigeminal sensory nuclei

What are inferior peduncle cerebellar efferents?

• Cerebellar corticovestibular fibers,

• cerebelloreticular fibers

What are middle peduncle cerebellar afferents?

Pontocerebellar fibers

What are middle peduncle cerebellar efferents?

None

What are superior peduncle cerebellar afferents?

• Ventral spinocerebellar tract,

• trigeminothalamic,

• rostral spinocerebellar tract

What are superior peduncle cerebellar efferents?

• Cerebellothalamic fibers,

• cerebellorubral fibers

What is the vestibulocerebellum also known as

Flocculonodular lobe

What information does the focculonodular lobe receive?

Vestibular

What motor neurons does the vestibulocerebllaum influence?

• Vestibulospinal tract,

• medial longitudinal fasciculus,

• reticulospinal fibers

What tracts convey proprioception, and other sensory information terminate in the cerebellum?

Spinocerebellar tracts and cuneocerebellar fibers

What is spinocerebellum output primarily control?

• Axial musculature through vermal cortex and fastigial nucleus efferents

• Limb musculature through efferents of the globose and emboliform nuclei

Where does the pontocerebellum get information from?

Contralateral pontine nuclei, pontocerebellar fibers (these fibers synapse on dentate nucleus and terminate on the VL)

Some of the pontine nuclei receive afferents from the ______ and may relay data used by the cerebellum in the control of ______

Superior colliculi, visually guided movements

A cerebellar hemisphere influences the musculature on the ____ side of the body

Same

What does the pontocerebellum do?

Ensures smooth and orderly sequence of muscle contraticion with accurate percision and force

Decomposition on movement

Breakdown of movement into individual components 

Ataxia

Unsteady, wide based gait, tendency to fall to the side of lesion

Dysmetria

Past pointing, tend to move past or short of an object when trying to point at it

Tremor

Intention tremor, finger to nose, more difficult as the finger approaches the nose, no tremor at rest

Dysdiadochokinesia

Difficulty with rapid alternating movements

What vessel supplies the superior cerebellum?

Superior cerebellar arteries

What vessels supply the inferior cerebellum?

Posterior inferior and anterior inferior cerebellar arteries

Where do the afferent fibers synapse as they enter the flocculonodular lobe?

fastigial nucleus

Archi =

vestibulocerebellum

Paleo =

Spinocerebellum

Neo =

Pontocerebellum

What does the vestibulocerebellum influence?

coordinates the actions of muscles that maintain equilibrium and participates in other motor responses, including those of the eyes, to vestibular stimulation

The spinocerebellum gets input from

• ant. and post. spinocerebellar tracts,

• cuneocerebellar tracts,

• olivocerebellar tract

where do the spinocerebellum fibers synapse on the way to the cortex?

fastigial, globose, and emboliform nuclei