The labelled components belong to which structure?
cerebellum
The smallest folds, which form the ridges visible on the outside of the cerebellum, are called folia. Groups of adjacent folia form lobules that are divided by fissures
What are the lobes and major fissures of the cerebellum?
anterior lobe
primary fissure
posterior lobe
flocularnodular lobe
posterolateral fissure
Why is the anterior lobe of the cerebellum, or the paleocerebellum, also described as the "spinal cerebellum"?
because the anterior lobe of the cerebellum receives its primary input from the spinal cord
What is the primary input of the posterior lobe of the cerebellum, or neocerebellum, and what tract transmits it?
primary input: cerebral cortex
signals from the cerebral cortex are transmitted to the cerebellum via relay neurons in the pontine nuclei
What two sub-components make the vestibulocerebellum?
nodulus of cerebellum
floculus of cerebellum
What is the primary input of the flocularnodular lobe of the cerebellum, or vestibulocerebellum?
primary input: vestibular labrynth/nerve and vestibular nuclei
What structure does the bottom of the cerebellum form?
4th ventricle
Which statement is false?
C. cerebellar damage always causes paralysis
What is the function of the cerebellum?
to make our movements as fast, accurate, consistent, and fluid as possible
What is the "vermis" and what 2 structures does it separate?
the vermis is the midline region of the cerebellum and it is in between the cerebellar hemispheres
What part of the cerebellum is not visible from this view?
floccularnodular lobe
What is the "tonsil" of the cerebellum and why is it clinically important?
the "tonsil" of the cerebellum is portion of the cerebellum adjacent to the medulla
the tonsil is clinically important because if there is trauma or chemical insult to the brain that results in brain swelling, the tonsil is forced through the foramen magnum (tonsil herniation) where it compresses the medulla, reducing blood supply to the medulla, kills patient by suppressing respiratory centers
Which area(s) of the cerebellum influence leg movements?
E. parts of anterior lobe and parts of the posterior lobe
What are the names of the cerebellar peduncles? Are they paired structures?
superior cerebellar peduncle (i.e. brachium conjunctivum)
Where do the fibers of the middle cerebellar peduncle originate and terminate?
originate: pontine nuclei (relaying info from cerebral cortex)
terminate: cerebellum
Which is the most lateral set of cerebellar peduncles?
D. middle cerebellar peduncles
What two types of fibers contribute to the inferior cerebellar peduncle?
climbing fibers
mossy fibers
What are the names of the input fibers that enter the cerebellum via the inferior peduncle and where do they originate? What types of information do they each transmit?
olivocerebellar: inferior olivary nuclei (contralateral somatosensory and proprioception)
reticulocerebellar: lateral reticular nucleus (ipsilateral movement of body in space)
vestibulocerebellar: vestibular nucleus (ipsilateral movement of head in space)
cuneocerebellar: lateral (external) cuneate nucleus (ipsilateral proprioception of arm)
posterior spinocerebellar: spinal cord (ipsilateral proprioception of leg)
What two nuclei within the inferior olive relay information to the cerebellum via the inferior peduncle? What types of information do they transmit, respectively?
medial accessory nerve (CN IX) nucleus: (contralateral) somatosensory information
dorsal accessory nerve (CN IX) nucleus: (contralateral) proprioceptive information
Which of the following inferior cerebellar peduncle tracts relays information to the cerebellum from the contralateral side of the body?
a. olivocerebellar
b. reticulocerebellar
c. vestibulocerebellar
d. cuneocerebellar
e. posterior spinocerebellar
a. olivocerebellar
Where do the fibers that travel to the cerebellum via the middle peduncle originate and terminate?
(cortico-ponto-cerebellar pathway)
fibers originate in the cortex (each from frontal, temporal, parietal, occipital lobes)
fibers from the cortex synapse on the ipsilateral pontine nuclei
postsynaptic fibers from the pontine nuclei cross to the contralateral cerebellar cortex (i.e. to contralateral middle peduncle)
the fibers terminate as mossy fibers in the granular layer of the cerebellar cortex
At what level do the signals carried in the cortico-ponto-cerebellar pathway cross to the contralateral side of the body?
at the level of the pontine nuclei
Which statement is false?
A. the dentate nucleus of the cerebellum is the smallest of the nuclei
What are the names of the cerebellar nuclei and how are the aligned? What areas of the cerebellar cortex are they connected to?
white matter layer: mossy and climbing fibers (going towards cortex); axons of dendritic cells
(deep)
In which direction do the parallel fibers of the molecular layer of the cerebellar cortex run? What are they parallel with?
the parallel fibers of the cerebellar cortex run medially-laterally
they are parallel to the long-axis of the folia of the cerebellum
True or False: The axons of the Purkinje cells in the cerebellar cortex project superficially towards the corex surface, not deep
False
What are the two components of the parallel fibers in the molecular layer of the cerebellar cortex?
dendrites of Purkinje cells
axons of granule cells
True or False: All output from the cerebellar cortex leaves the cortex via Purkinje cell axons.
True
From which structures do mossy fibers entering the cerebellum originate?
pontine nuclie
(spinal cord) external cuneate (forelimb)
(spinal cord) Clarke's column (hindlimb)
vestibular nuclei
vestibular nerve
reticular nuclei
trigeminal nucleus (head)
From which structures do climbing fibers entering the cerebellum originate?
inferior olive
medial accessory nerve nucleus
dorsal accessory nerve nucleus
True or False: In the cerebellar cortex, the molecular layer is mostly densely packed cells and the granular layer is mostly fibers with a few scattered cells.
False
In which cerebellar cortex layer does a mossy fiber terminate?
granular layer
Where do the fibers of the superior cerebellar peduncle originate and terminate?
originate: cerebellar nuclei
terminate: in structures that send signals down spinal cord to spinal motoneurons
motor regions of cerebral cortex (via thalamus relay)
red nuclei
vestibular nuclei
reticular nuclei
At what level is the ventral tegmental decussation? What tracts cross in this region?
midbrain
rubrobulbar, rubrospinal, tegmentospinal tracts
Where do the fibers from the dentate and interpositus nucleui of the cerebellum terminate?
red nucleus
thalamus
What are the 6 major signs associated with cerebellar damage?
postural instability (static: unable to maintain posture standing; dynamic: unable to maintain posture while walking --> ataxia)
delayed movement (start/stop)
deficit in performing continuous/repetitive movements (alternating movements)
movement dysmetria (wrong movement size)
movement decomposition (movements that require several simultaneous joint rotations)
motor learning/adaptation deficit (movement is repeatedly inaccurate)
Damage to which area of the cerebellum is responsible for postural instability?
vestibulocerebellum
i.e. flocculonodular lobe of cerebellum
Damage to which area of the cerebellum is responsible for delayed movment (start/stop), deficit in performing continuous/repetitive movements?
neocerebellum
i.e. posterior lobe of cerebellum
Patients who present with dysdiadochokinesis (difficulty with rapidly alternating movements) may have damage to which area of the cerebellum?
neocerebellum
Damage to which are of the cerebellum is responsible for dysmetria (wrong movement size)?
neocerebellum and/or paleocerebellum
(damage to any area of the cerebellum may ultimately lead to dysmetria in different areas of body)
Damage to which area of the cerebellum is responsible for movement decomposition (can only rotate one joint at a time in a sequence)?
neocerebellum and/or paleocerebellum
Damage to which cerebellar area will cause motor learning/adaptation deficit (movement is repeatedly inaccurate)?
damage to any part of the cerebellum will result in motor learning deficits
Does the cerebellum exhibit somatotopy?
Yes, the cerebellum exhibits somatotopy
the somatotopy of the cerebellum is not as well-defined as in the motor or somatosensory cortex
(e.g. the visual and auditory area also relates to eye movements)
Which brain structures are bigger in higher animals?
dentate nucleus of cerebellum
cerebral cortex
lateral cerebellar cortex
pontine nuclei
principle nucleus of inferior olive (supplies climbing fibers to lateral cerebellar cortex)
