Week 11 Content Flashcards
Where does the cerebellum sit
- Posterior to brainstem
- Inferior to occipital and temporal lobes
- Within the posterior fossa
How is the cerebellum separated from the occipital and temporal lobes
By the tentorium cerebelli
How is the cerebellum separated from the brainstem
By the fourth ventricle
Orientation of white and gray matter for cerebellum
- White matter on the inside
- Gray matter on the outside
What are the three major cerebellum lobes
- Anterior
- Posterior
- Flocculo-nodular
How are the major lobes divided
- Primary fissure (anterior and posterior)
- Posterolateral fissure (flocculo-nodular and posterior)
What are folia
Outward and inward folds on the surface of the cerebellum that increase its surface area
What are the four functional regions/zones of the cerebellum
- Vermis
- Intermediate
- Lateral
- Flocculo-motor
How are the functional regions/zone oriented
- Vermis = central
- Intermediate = inner 1/3 of the big lobe
- Lateral = outer 1/3 of the big lobe
- Flocculo-motor = encompasses the nodule and flocculus
How many nodules are there
One
How many flocculus are there
Two
What is deep within the cerebellum
Deep cerebellar nuclei
What is the order of the deep cerebellar nuclei (later to medial)
- Dentate
- Emboliform (interposed)
- Globose (interposed)
- Fastigial
- Don’t Eat Greasy Foods
Where do the deep cerebellar nuclei sit
- Dentate = lateral zone
- Interposed (emboliform and globose) = intermediate zone
- Fastigial = vermis + intermediate zone
What wraps around the pons at the level of the brainstem that then enters the cerebellum
White matter called the cerebellar peduncles
What are the three cerebellar peduncles
- Superior
- Middle
- Inferior
What are the functions of the cerebellar peduncles
- Superior = carries cerebellar outputs
- Middle/inferior = carries cerebellar inputs
What are the three inputs to the cerebellum
- Efferent copy of descending motor commands
- Afferent copy from sensory receptors
- Vestibular system inputs
How does the cerebellum get efferent copies of descending motor commands
- Corticopontine fibers from cortical motor areas travel to and synapse on the ipsilateral pontine nuclei
- Pontocerebellar fibers immediately cross the midline and enter the contralateral cerebellum through middle cerebellar peduncles
What are the two tracts that carry afferent copies to the cerebellum
- Cuneocerebellar tract
- Dorsal spinal-cerebellar tract
Cuneocerebellar tract (what and how)
Carries sensory information from the arms and upper trunk
- Synapses onto the external cuneate nucleus (lateral to the nucleus cuneatus)
- Enters cerebellum via inferior cerebellar peduncle
Dorsal spinal-cerebellar tract (what and how)
Carries sensory information from the lower trunk and legs
- Synapses onto the nucleus dorsalis of Clark (found in intermediate zone of spinal cord)
- Enters cerebellum via inferior cerebellar peduncle
What side of the body is the cerebellum receiving sensory information from
The ipsilateral side
How does the cerebellum receive vestibular system inputs
The primary vestibular sensory neurons and vestibular nuclei project to the ipsilateral cerebellum via the juxtarestiform body
What is the juxtarestiform body
It is an area for vestibular input in the inferior cerebellar peduncles
Cerebellar output pathways
- Dentate nucleus
- Interposed nucleus
- Fastigial nucleus
- Inferior vermis and flocculonodular lobe
Dentate nucleus output pathway
Travels via contralateral thalamus to:
- Pre-motor cortex
- Supplementary motor area
- Primary motor cortex
- Parietal cortex
- Exits superior cerebellar peduncle
- Crosses midline at the level of the midbrain
- Travels to contralateral thalamus
Bonus Pathway
- Exits superior cerebellar peduncle
- Synapse onto contralateral red nucleus
What is the dentate nucleus output involved in
Motor planning and coordination for the ipsilateral lateral corticospinal tract
Some motor learning
Interposed nucleus output pathway
Via contralateral thalamus to:
- Pre-motor cortex
- Supplementary motor area
- Primary motor cortex
- Exits superior cerebellar peduncle
- Crosses midline at the level of the midbrain
Bonus Pathway
- Exits superior cerebellar peduncle to contralateral red nucleus
What is the interposed nucleus output involved in
Influences online coordination of movement and distal limbs via the ipsilateral lateral corticospinal tract
Influences arms via ipsilateral rubrospinal tract
Fastigial nucleus output pathway
Via contralateral thalamus
- Exit superior cerebellar peduncle
- Crosses midline at level of midbrain
- Goes to contralateral thalamus
- Then goes to motor areas of the cortex
Bilateral projections to the vestibular nuclei
Bilateral projections to the reticular formation
What is the fastigial nucleus involved in
Controlling trunk/neck movements
Influences vestibulospinal tract and vestibular reflexes (balance/tone)
Influences reticular reflexes (balance/tone)
Inferior Vermis and flocculonodular lobe output pathway
Projects ipsilaterally to the vestibular nuclei
What are the inferior Vermis and flocculonodular lobe involved in
Influencing balance and eye movement
Somatotopic organization of the cerebellum
Two body orientations:
- One in anterior lobe
- One in posterior lobe
Organization found in the upper portion of the vermis and the intermediate zone of the cerebellum as it controls online control of movement
Where is limb representation found in the cerebellum
The intermediate zone
Where is trunk and limb representation found in the cerebellum
The vermis
Main role of the cerebellum
- Receives a copy of both efferent and afferent information
- Compares intended goal of movement to the actual motor response
- Projects this information back to the motor cortex and motor areas to allow for a correction of the movement
Where would cerebellar deficits show up
On the ipsilateral side of the injury due to double cross over
